Patent Application
20240327802
The instant application contains a Sequence Listing which has been submitted herewith and is hereby incorporated by reference in its entirety. Said .xml file, created on Jun. 26, 2024, is named 749363_BEAM9-005_ST26.xml and is 640.494 bytes in size.
Gene therapies largely involve the use of viral gene delivery systems in order to transduce a cell of interest and express a transgene. Viral systems that are commonly used for gene therapy are derived from viruses and suffer from significant disadvantages. The challenges in using current viral systems include: limited, small packaging capacities; unintended resultant consequences such as genomic integration; limited tissue tropism; pre-existing immunity and/or immune responses in the target population, limited ability for re-dosing; and limited durability due to genome instability, immune clearance, and cellular toxicity. For example, while adenoviral vector-mediated gene therapy demonstrates high transduction efficiency and can be used to infect many different cell types, certain disadvantages include non-integration and high immunogenicity. Disadvantages of adeno-associated viral vector-mediated gene therapy include high immunogenicity, and limited packaging capacity. As another example, retroviral vector-mediated gene therapy suffers from low transduction efficiency and the inactivation by complement.
Accordingly, there is a need for novel viral gene delivery systems that are advantages over current viral systems.
In one aspect, the disclosure provides a pseudotyped recombinant rabies virus (RABV) particle, comprising a chimeric envelope protein and a recombinant RABV genome, wherein:
In certain embodiments, the chimeric envelope protein retains target receptor binding activity compared to a wild-type version of the non-RABV envelope protein.
In certain embodiments, the chimeric envelope protein retains target receptor binding activity and fusion activity compared to a wild-type version of the non-RABV envelope protein.
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain are from the same envelope protein.
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 90% identity to SEQ ID NO: 390 (RRVNRSEPTQHNLRGTGREVSVTPQSGKIISSWESHKSGGETRL). In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 390 (RRVNRSEPTQHNLRGTGREVSVTPQSGKIISSWESHKSGGETRL). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 390 (RRVNRSEPTQHNLRGTGREVSVTPQSGKIISSWESHKSGGETRL).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 90% identity to SEQ ID NO: 391 (RRANRPESKQRSFGGTGGNVSVTSQSGKVIPSWESYKSGGEIRL). In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 391 (RRANRPESKQRSFGGTGGNVSVTSQSGKVIPSWESYKSGGEIRL). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 391 (RRANRPESKQRSFGGTGGNVSVTSQSGKVIPSWESYKSGGEIRL).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 90% identity to SEQ ID NO: 392 (KKGGRRNSPTNRPDLPIGLSTTPQPKSKVISSWESYKGTSNV). In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 392 (KKGGRRNSPTNRPDLPIGLSTTPQPKSKVISSWESYKGTSNV). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 392 (KKGGRRNSPTNRPDLPIGLSTTPQPKSKVISSWESYKGTSNV).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 90% identity to SEQ ID NO: 393 (GRVNRPKSTQRNLGGTERKVSVTSQSGKVISSWESYKSGGETRL). In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: SEQ ID NO: 393 (GRVNRPKSTQRNLGGTERKVSVTSQSGKVISSWESYKSGGETRL). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 393 (GRVNRPKSTQRNLGGTERKVSVTSQSGKVISSWESYKSGGETRL).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 90% identity to SEQ ID NO: 394 (LRCRAGRNRRTIRSNHRSLSHDVVFHKDKDKVITSWESYKGQTAQ). In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 394 (LRCRAGRNRRTIRSNHRSLSHDVVFHKDKDKVITSWESYKGQTAQ). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 394 (LRCRAGRNRRTIRSNHRSLSHDVVFHKDKDKVITSWESYKGQTAQ).
In certain embodiments, the non-RABV envelope protein ectodomain and/or the non-RABV envelope protein transmembrane domain are not from a lyssavirus.
In certain embodiments, the non-RABV envelope protein ectodomain comprises an envelope protein ectodomain from a Rhabdoviridae family virus.
In certain embodiments, the non-RABV envelope protein transmembrane domain comprises an envelope protein transmembrane domain from a Rhabdoviridae family virus.
In certain embodiments, the Rhabdoviridae family virus comprises an ephemerovirus, a tibrovirus, an almendravirus, a novirhabdovirus, a tupavirus, or a moussa virus (MOUV).
In certain embodiments, the ephemerovirus is bovine ephemeral fever virus (BEFV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a BEFV amino acid sequence comprising at least 90% identity to SEQ ID NO: 395
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a BEFV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 395.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 396
In certain embodiments, the certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 396.
In certain embodiments, the tibrovirus is an ekpoma virus 1 (EKV1) or an ekpoma virus 2 (EKV2).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a EKV1 amino acid sequence comprising at least 90% identity to SEQ ID NO: 397
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a EKV1 amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 397.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 398
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 398.
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a EKV2 amino acid sequence comprising at least 90% identity to SEQ ID NO: 399
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a EKV2 amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 399.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO. 400
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 400.
In certain embodiments, the tibrovirus is a Bas-Congo tibrovirus (BASV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a BASV amino acid sequence comprising at least 90% identity, to SEQ ID NO: 401
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a BASV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 401.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 402
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO; 402.
In certain embodiments, the tibrovirus is a tibrogargan virus (TIBV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a TIBV amino acid sequence comprising at least 90% identity to SEQ ID NO: 403
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a TIBV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 403.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 404
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 404.
In certain embodiments, the almendravirus is arboretum virus (ABTV) or balsa virus (BALV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an ABTV amino acid sequence comprising at least 90% identity to SEQ ID NO: 405
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an ABTV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 405.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO; 406
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO; 4016.
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an BALV amino acid sequence comprising at least 90% identity to SEQ ID NO: 407
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an BALV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO. 407.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 408
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 408.
In certain embodiments, the novirhabdovirus is viral hemorrhagic septicemia virus (VSHV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an VSHV amino acid sequence comprising at least 90% identity to SEQ ID NO: 409
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an VSHV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 409.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 410
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 410.
In certain embodiments, the tupavirus is tupaia Virus (TUPV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an TUPV amino acid sequence comprising at least 90% identity to SEQ ID NO: 411
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an TUPV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 411.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 412
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 412.
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an MOUV amino acid sequence comprising at least 90% identity to SEQ ID NO: 413
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an MOUV amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 413.
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 414
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to SEQ ID NO: 414.
In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than: about 300 bp, about 400 bp, about 500 bp, about 600 bp, about 700 bp, about 800 bp, about 900 bp, about 1,000 bp, about 1,100 bp, about 1,200 bp, about 1,300 bp, about 1,400 bp, about 1,500 bp, about 1,600 bp, about 1,700 bp, about 1,800 bp, about 1,900 bp, about 2,000 bp, about 2,100 bp, about 2,200 bp, about 2,300 bp, about 2,400 bp, about 2,500 bp, about 2,600 bp, about 2,700 bp, about 2,800 bp, about 2,900 bp, or about 3,000 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 300 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 650 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 1,000 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 3,000 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 4,500 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 8,500 bp. In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 10,000 bp.
In certain embodiments, the therapeutic transgene comprises a nucleic acid editing system or a component thereof.
In certain embodiments, the nucleic acid editing system or component thereof is selected from the group consisting of a Clustered Regulatory Interspaced Short Palindromic Repeat (CRISPR) system, a zinc finger protein (ZF), a meganuclease, and a Transcription Activator-Like Effector-based protein (TALE).
In certain embodiments, the nucleic acid editing system is a CRISPR system.
In certain embodiments, the CRISPR-system comprises a nucleobase editor comprising a polynucleotide programmable nucleotide binding domain and a nucleobase editing domain.
In certain embodiments, the nucleobase editing domain is an adenosine deaminase, cytidine deaminase, cytosine deaminase, or a functional variant thereof.
In certain embodiments, the nucleobase editing domain is an adenosine deaminase.
In certain embodiments, the adenosine deaminase is selected from the group consisting of: ABE 0.1, ABE 0.2, ABE 1.1, ABE 1.2, ABE2.1, ABE2.2, ABE2.3, ABE2.4, ABE2.5, ABE2.6, ABE2.7, ABE2.8, ABE2.9, ABE2.10, ABE2.11, ABE2.12, ABE3.1, ABE3.2, ABE3.3, ABE3.4, ABE3.5, ABE3.6, ABE3.7, ABE3.8, ABE4.1, ABE4.2, ABE4.3, ABE5.1, ABE5.2, ABE5.3, ABE5.4, ABE5.5, ABE5.6, ABE5.7, ABE5.8, ABE5.9, ABE5.10, ABE5.11, ABE5.12, ABE5.13, ABE5.14, ABE6.1, ABE6.2, ABE6.3, ABE6.4, ABE6.5, ABE6.6, ABE7.1, ABE7.2, ABE7.3, ABE7.4, ABE7.5, ABE7.6, ABE7.7, ABE7.8, ABE 7.9, ABE7.10, ABE8.1-m, ABE8.2-m, ABE8.3-m, ABE8.4-m, ABE8.5-m, ABE8.6-m, ABE8.7-m, ABE8.8-m, ABE8.9-m, ABE8.10-m, ABE8.11-m, ABE8.12-m, ABE8.13-m, ABE8.14-m, ABE8.15-m, ABE8.16-m, ABE8.17-m, ABE8.18-m, ABE8.19-m, ABE8.20-m, ABE8.21-m, ABE8.22-m, ABE8.23-m, ABE8.24-m, ABE8.l-d, ABE8.2-d, ABE8.3-d, ABE8.4-d, ABE8.5-d, ABE8.6-d, ABE8.7-d, ABE8.8-d, ABE8.9-d, ABE8.10-d, ABE8.11-d, ABE8.12-d, ABE8.13-d, ABE8.14-d, ABE8.15-d, ABE8.16-d, ABE8.17-d, ABE8.18-d, ABE8.19-d, ABE8.20-d, ABE8.21-d, ABE8.22-d, ABE8.23-d, ABE8.24-d, ABE8a-m, ABE8b-m, ABE8c-m, ABE8d-m, ABE8e-m, ABE8a-d, ABE8b-d, ABE8c-d, ABE8d-d, ABE8e-d, ABE9.1, ABE9.2, ABE9.3, ABE9.4, ABE9.5, ABE9.6, ABE9.7, ABE9.8, ABE9.9, ABE9.10, ABE9.11, ABE9.12, ABE9.13, ABE9.14, ABE9.15, ABE9.16, ABE9.17, ABE9.18, ABE9.19, ABE9.2, ABE9.21, ABE9.22, ABE9.23, ABE9.24, ABE9.25, ABE9.26, ABE9.27, ABE9.28, ABE9.29, ABE9.30, ABE9.31, ABE9.32, ABE9.33, ABE9.34, ABE9.35, ABE9.36, ABE9.37, ABE9.38, ABE9.39, ABE9.40, ABE9.41, ABE9.42, ABE9.43, ABE9.44, ABE9.45, ABE9.46, ABE9.47, ABE9.48, ABE9.49, ABE9.50, ABE9.51, ABE9.52, ABE9.53, ABE9.54, ABE9.55, ABE9.56, ABE9.57, and ABE9.58. In certain embodiments, the adenosine deaminase is ABE7.10.
In certain embodiments, the polynucleotide programmable nucleotide binding domain is a Cas9 polypeptide, a Cas12 polypeptide, or a functional variant thereof.
In certain embodiments, the CRISPR-system further comprises a guide RNA (gRNA) or a nucleic acid sequence encoding a gRNA.
In certain embodiments, the therapeutic transgene comprises a therapeutic polypeptide and/or a therapeutic nucleic acid.
In certain embodiments, the therapeutic transgene is operably linked to a transcriptional regulatory element.
In certain embodiments, the transcriptional regulatory element comprises a transcription initiation signal.
In certain embodiments, the transcription initiation signal is exogenous to the rabies virus
In certain embodiments, the transcription initiation signal is endogenous to the rabies virus.
In certain embodiments, the therapeutic transgene is operably linked to a transcription termination polyadenylation signal.
In certain embodiments, the recombinant RABV genome lacks a G gene encoding for a envelope protein or a functional variant thereof, and/or the genome lacks an L gene encoding for a polymerase or a functional variant thereof.
In certain embodiments, the recombinant RABV genome lacks a G gene encoding for a envelope protein or a functional variant thereof.
In certain embodiments, the recombinant RABV genome lacks a G gene encoding for a envelope protein or a functional variant thereof, and wherein the genome lacks an L gene encoding for a polymerase or a functional variant thereof.
In certain embodiments, the recombinant RABV genome comprises:
In certain embodiments, the recombinant RABV genome lacks:
In certain embodiments, the recombinant RABV particle is capable of transducing a human cell, wherein the human cell expresses the therapeutic transgene.
In certain embodiments, the recombinant RABV genome does not encode an envelope protein or fragment thereof.
In one aspect, the disclosure provides a pharmaceutical composition comprising the pseudotyped particle described herein.
In another aspect, the disclosure provides a method for expressing a therapeutic transgene in a target cell, comprising transducing a target cell with the pseudotyped particle described herein. In certain embodiments, the target cell is a human cell. In certain embodiments, the target cell is in a human.
In another aspect, the disclosure provides a method for delivering a therapeutic transgene to a subject, comprising administering to the subject the pseudotyped particle described herein, or the pharmaceutical composition described herein.
Unless defined otherwise, all technical and scientific terms used herein have the meaning commonly understood by a person skilled in the art to which this invention belongs. The following references provide one of skill with a general definition of many of the terms used in this invention: Singleton et al., Dictionary of Microbiology and Molecular Biology (2nd ed. 1994): The Cambridge Dictionary of Science and Technology (Walker ed., 1988): The Glossary of Genetics, 5th Ed., R. Rieger et al. (eds.). Springer Verlag (1991); and Hale & Marham, The Harper Collins Dictionary of Biology (1991). As used herein, the following terms have the meanings ascribed to them below, unless specified otherwise.
By “adenine” or “9H-Purin-6-amine” is meant a purine nucleobase with the molecular formula C5H5N5, having the structure
and corresponding to CAS No. 73-24-5.
By “adenosine” or “4-Amino-1-[(2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]pyrimidin-2(1H)-one” is meant an adenine molecule attached to a ribose sugar via a glycosidic bond, having the structure
and corresponding to CAS No. 65-46-3. Its molecular formula is C10H13N5O4.
By “adenosine deaminase” or “adenine deaminase” is meant a polypeptide or fragment thereof capable of catalyzing the hydrolytic deamination of adenine or adenosine. In some embodiments, the deaminase or deaminase domain is an adenosine deaminase catalyzing the hydrolytic deamination of adenosine to inosine or deoxy adenosine to deoxyinosine. In some embodiments, the adenosine deaminase catalyzes the hydrolytic deamination of adenine or adenosine in deoxyribonucleic acid (DNA). The adenosine deaminases (e.g. engineered adenosine deaminases, evolved adenosine deaminases) provided herein may be from any organism (e.g., eukaryotic, prokaryotic), including but not limited to algae, bacteria, fungi, plants, invertebrates (e.g., insects), and vertebrates (e.g., amphibians, mammals). In some embodiments, the adenosine deaminase is an adenosine deaminase variant with one or more alterations and is capable of deaminating both adenine and cytosine in a target polynucleotide (e.g., DNA, RNA) and may be referred to as a “dual deaminase”. Non-limiting examples of dual deaminases include those described in PCT/US22/22050. In some embodiments, the target polynucleotide is single or double stranded. In some embodiments, the adenosine deaminase variant is capable of deaminating both adenine and cytosine in DNA. In some embodiments, the adenosine deaminase variant is capable of deaminating both adenine and cytosine in single-stranded DNA. In some embodiments, the adenosine deaminase variant is capable of deaminating both adenine and cytosine in RNA. In embodiments, the adenosine deaminase variant is selected from those described in PCT/US2020/018192, PCT/US2020/049975, PCT/US2017/045381, and PCT/US2020/028568, the full contents of which are each incorporated herein by reference in their entireties for all purposes.
By “adenosine deaminase activity” is meant catalyzing the deamination of adenine or adenosine to guanine in a polynucleotide. In some embodiments, an adenosine deaminase variant as provided herein maintains adenosine deaminase activity (e.g., at least about 30%, 40%, 50%, 60%, 70%, 80%, 90% or more of the activity of a reference adenosine deaminase (e.g., TadA*8.20 or TadA*8.19)).
By “Adenosine Base Editor (ABE)” is meant a base editor comprising an adenosine deaminase.
By “Adenosine Base Editor (ABE) polynucleotide” is meant a polynucleotide encoding an ABE. By “Adenosine Base Editor 8 (ABE8) polypeptide” or “ABE8” is meant a base editor as defined herein comprising an adenosine deaminase or adenosine deaminase variant comprising one or more of the alterations listed in Table 13, one of the combinations of alterations listed in Table 13, or an alteration at one or more of the amino acid positions listed in Table 13, such alterations are relative to the following reference sequence: MSEVEFSHEYWMRHALTLAKRARDEREVPVGAVLVLNNRVIGEGWNRAIGLHDPTAHAEIMALR QGGLVMQNYRLIDATLYVTFEPCVMCAGAMIHSRIGRVVFGVRNAKTGAAGSLMDVLHYPGMNH RVEITEGILADECAALLCYFFRMPRQVFNAQKKAQSSTD (SEQ ID NO: 1), or a corresponding position in another adenosine deaminase. In embodiments, ABE8 comprises alterations at amino acids 82 and/or 166 of SEQ ID NO: 1 In some embodiments, ABE8 comprises further alterations, as described herein, relative to the reference sequence.
By “Adenosine Base Editor 8 (ABE8) polynucleotide” is meant a polynucleotide encoding an ABE8 polypeptide.
“Administering” is referred to herein as providing one or more compositions described herein to a patient or a subject. By way of example and without limitation, composition administration (e.g., injection) can be performed by intravenous (i.v.) injection, sub-cutaneous (s.c.) injection, intradermal (i.d.) injection, intraperitoneal (i.p.) injection, or intramuscular (i.m.) injection. One or more such routes can be employed. Parenteral administration can be, for example, by bolus injection or by gradual perfusion over time. In some embodiments, parenteral administration includes infusing or injecting intravascularly, intravenously, intramuscularly, intraarterially, intrathecally, intratumorally, intradermally, intraperitoneally, transtracheally, subcutaneously, subcuticularly, intraarticularly, subcapsularly, subarachnoidly and intrastemally. Alternatively, or concurrently, administration can be by the oral route.
By “agent” is meant any small molecule chemical compound, antibody, nucleic acid molecule, or polypeptide, or fragments thereof.
By “alteration” is meant a change in the level, structure, or activity of an analyte, gene or polypeptide as detected by standard art known methods such as those described herein. As used herein, an alteration includes a change (e.g. increase or decrease) in expression levels. In embodiments, the increase or decrease in expression levels is by 10%, 25%, 40%, 50% or greater. In some embodiments, an alteration includes an insertion, deletion, or substitution of a nucleobase or amino acid (by, e.g., genetic engineering).
By “ameliorate” is meant decrease, suppress, attenuate, diminish, arrest, or stabilize the development or progression of a disease.
By “analog” is meant a molecule that is not identical, but has analogous functional or structural features. For example, a polypeptide analog retains the biological activity of a corresponding naturally-occurring polypeptide, while having certain biochemical modifications that enhance the analog's function relative to a naturally occurring polypeptide. Such biochemical modifications could increase the analog's protease resistance, membrane permeability, or half-life, without altering, for example, ligand binding. An analog may include an unnatural amino acid.
As used herein, the term “antibody” refers to an immunoglobulin molecule that specifically binds to, or is immunologically reactive with, a particular antigen, and includes polyclonal, monoclonal, genetically engineered, and otherwise modified forms of antibodies, including but not limited to chimeric antibodies, humanized antibodies, heteroconjugate antibodies (e.g., bi- tri- and quad-specific antibodies, diabodies, triabodies, and tetrabodies), and antigen binding fragments of antibodies, including, for example, Fab′, F(ab′)2, Fab, Fv, rIgG, and scFv fragments. Unless otherwise indicated, the term “monoclonal antibody” (mAb) is meant to include both intact molecules, as well as antibody fragments (including, for example, Fab and F(ab′)2 fragments) that are capable of specifically binding to a target protein. As used herein, the Fab and F(ab′)2 fragments refer to antibody fragments that lack the Fc fragment of an intact antibody.
Antibodies (immunoglobulins) comprise two heavy chains linked together by disulfide bonds, and two light chains, with each light chain being linked to a respective heavy chain by disulfide bonds in a “Y” shaped configuration. Each heavy chain has at one end a variable domain (VH) followed by a number of constant domains (CH). Each light chain has a variable domain (VL) at one end and a constant domain (CL) at its other end. The variable domain of the light chain (VL) is aligned with the variable domain of the heavy chain (VL), and the light chain constant domain (CL) is aligned with the first constant domain of the heavy chain (CH1). The variable domains of each pair of light and heavy chains form the antigen binding site. The isotype of the heavy chain (gamma, alpha, delta, epsilon or mu) determines the immunoglobulin class (IgG, IgA, IgD, IgE or IgM, respectively). The light chain is either of two isotypes (kappa (κ) or lambda (λ)) found in all antibody classes. The terms “antibody” or “antibodies” include intact antibodies, such as polyclonal antibodies or monoclonal antibodies (mAbs), as well as proteolytic portions or fragments thereof, such as the Fab or F(ab′)2 fragments, that are capable of specifically binding to a target protein. Antibodies may include chimeric antibodies; recombinant and engineered antibodies, and antigen binding fragments thereof. Exemplary functional antibody fragments comprising whole or essentially whole variable regions of both the light and heavy chains are defined as follows: (i) Fv, defined as a genetically engineered fragment consisting of the variable region of the light chain and the variable region of the heavy chain expressed as two chains; (ii) single-chain Fv (“scFv”), a genetically engineered single-chain molecule including the variable region of the light chain and the variable region of the heavy chain, linked by a suitable polypeptide linker; (iii) Fab, a fragment of an antibody molecule containing a monovalent antigen-binding portion of an antibody molecule, obtained by treating an intact antibody with the enzyme papain to yield the intact light chain and the Fd fragment of the heavy chain, which consists of the variable and CH1 domains thereof; (iv) Fab′, a fragment of an antibody molecule containing a monovalent antigen-binding portion of an antibody molecule, obtained by treating an intact antibody with the enzyme pepsin, followed by reduction (two Fab′ fragments are generated per antibody molecule); and (v) F(ab′)2, a fragment of an antibody molecule containing a monovalent antigen-binding portion of an antibody molecule, obtained by treating an intact antibody with the enzyme pepsin (i.e., a dimer of Fab′ fragments held together by two disulfide bonds).
By “base editor (BE),” or “nucleobase editor polypeptide (NBE)” is meant an agent that binds a polynucleotide and has nucleobase modifying activity. In various embodiments, the base editor comprises a nucleobase modifying polypeptide (e.g., a deaminase) and a polynucleotide programmable nucleotide binding domain (e.g., Cas9 or Cpf1) in conjunction with a guide polynucleotide (e.g., guide RNA (gRNA)). Representative nucleic acid and protein sequences of base editors include those sequences with about or at least about 85% sequence identity to any base editor sequence provided in the sequence listing, such as those corresponding to SEQ ID NOs: 2-11.
By “BE4 cytidine deaminase (BE4) polypeptide,” is meant a base editor comprising a nucleic acid programmable DNA binding protein (napDNAbp) domain, a cytidine deaminase domain, and two uracil glycosylase inhibitor domains (UGIs). In embodiments, the napDNAbp is a Cas9n(D10A) polypeptide. Non-limiting examples of cytidine deaminase domains include rAPOBEC, ppAPOBEC, RrA3F, AmAPOBEC1, and SsAPOBEC3B.
By “BE4 cytidine deaminase (BE4) polynucleotide,” is meant a polynucleotide encoding a BE4 polypeptide.
By “base editing activity” is meant acting to chemically alter a base within a polynucleotide. In one embodiment, a first base is converted to a second base. In one embodiment, the base editing activity is cytidine deaminase activity. e.g., converting target C·G to T·A. In another embodiment, the base editing activity is adenosine or adenine deaminase activity, e.g., converting A·T to G·C.
The term “base editor system” refers to an intermolecular complex for editing a nucleobase of a target nucleotide sequence. In various embodiments, the base editor (BE) system comprises (1) a polynucleotide programmable nucleotide binding domain, a deaminase domain (e.g., cytidine deaminase or adenosine deaminase) for deaminating nucleobases in the target nucleotide sequence; and (2) one or more guide polynucleotides (e.g., guide RNA) in conjunction with the polynucleotide programmable nucleotide binding domain. In various embodiments, the base editor (BE) system comprises a nucleobase editor domain selected from an adenosine deaminase or a cytidine deaminase, and a domain having nucleic acid sequence specific binding activity. In some embodiments, the base editor system comprises (1) a base editor (BE) comprising a polynucleotide programmable DNA binding domain and a deaminase domain for deaminating one or more nucleobases in a target nucleotide sequence; and (2) one or more guide RNAs in conjunction with the polynucleotide programmable DNA binding domain. In some embodiments, the polynucleotide programmable nucleotide binding domain is a polynucleotide programmable DNA binding domain. In some embodiments, the base editor is a cytidine base editor (CBE). In some embodiments, the base editor is an adenine or adenosine base editor (ABE). In some embodiments, the base editor is an adenine or adenosine base editor (ABE) or a cytidine or cytosine base editor (CBE). In some embodiments, the base editor system (e.g., a base editor system comprising a cytidine deaminase) comprises a uracil glycosylase inhibitor or other agent or peptide (e.g., a uracil stabilizing protein such as provided in WO2022015969, the disclosure of which is incorporated herein by reference in its entirety for all purposes) that inhibits the inosine base excision repair system.
The term “Cas9” or “Cas9 domain” refers to an RNA guided nuclease comprising a Cas9 protein, or a fragment thereof (e.g., a protein comprising an active, inactive, or partially active DNA cleavage domain of Cas9, and/or the gRNA binding domain of Cas9). A Cas9 nuclease is also referred to sometimes as a casnl nuclease or a CRISPR (clustered regularly interspaced short palindromic repeat) associated nuclease.
By “chimeric antigen receptor” or “CAR” is meant a synthetic or engineered receptor comprising an extracellular antigen binding domain operationally joined to one or more intracellular signaling domains that confers specificity for an antigen onto an immune effector cell. In some cases, the intracellular signaling domain is a T cell signaling domain. In embodiments, the immune effector cell is a T cell, an NK cell, or a macrophage. In embodiments, the CAR is a SUPRA CAR, an anti-tag CAR, a TCR-CAR, or a TCR-like CAR (see, e.g., Guedan, et al. “Engineering and Design of Chimeric Antigen Receptors,” Methods and Clinical Development, 12:145-156 (2019); Poorebrahim, et al., “TCR-like CARs and TCR-CARs targeting neoepitopes: an emerging potential,” Cancer Gene Therapy, 28:581-589 (2021); and Minutolo, et al. “The Emergence of Universal Immune Receptor T Cell Therapy for Cancer,” Front Oncol., 9:176 (2019), the disclosures of which are incorporated herein by reference in their entireties for all purposes).
By “chimeric antigen receptor (CAR) T cell” or “CAR-T cell” is meant a T cell expressing a CAR that has antigen specificity determined by the antibody-derived targeting domain of the CAR. As used herein, “CAR-T cells” includes T cells, regulatory T cells (Tux), or NK cells. As used herein, “CAR-T cells” include cells engineered to express a CAR or a T cell receptor (TCR, sometimes referred to as TCR-CARs or TCR-like CARs). Methods of making CARs (e.g., for treatment of cancer) are publicly available (see, e.g., Park et al., Trends Biotechnol., 29:550-557, 2011; Grupp et al., N Engl J Med., 368:1509-1518, 2013; Han et al., J. Hematol Oncol. 6:47, 2013: Haso et al., (2013) Blood, 121, 1165-1174; Mohseni, et al., (2020) Front. Immunol., 11, art. 1608, doi: 10.3389/fimmu.2020.01608; Eggenhuizen, et al. Int. J. Mol. Sci. (2020), 21:7015, doi: 10.3390/ijms2l 197015; Poorebrahim, et al., Cancer Gene Ther 28, 581-589 (2021), doi.org/10.1038/s41417-021-00307-7, PCT Pubs. WO2012/079000, WO2013/059593; and U.S. Pub. 2012/0213783, the disclosure of each of which is incorporated herein by reference herein in its entirety). The term “conservative amino acid substitution” or “conservative mutation” refers to the replacement of one amino acid by another amino acid with a common property. A functional way to define common properties between individual amino acids is to analyze the normalized frequencies of amino acid changes between corresponding proteins of homologous organisms (Schulz, G. E. and Schirmer, R. H., Principles of Protein Structure, Springer-Verlag, New York (1979)). According to such analyses, groups of amino acids can be defined where amino acids within a group exchange preferentially with each other, and therefore resemble each other most in their impact on the overall protein structure (Schulz. G. E. and Schirmer, R. H., supra). Non-limiting examples of conservative mutations include amino acid substitutions of amino acids, for example, lysine for arginine and vice versa such that a positive charge can be maintained; glutamic acid for aspartic acid and vice versa such that a negative charge can be maintained; serine for threonine such that a free —OH can be maintained; and glutamine for asparagine such that a free —NH2 can be maintained.
The term “coding sequence” or “protein coding sequence” as used interchangeably herein refers to a segment of a polynucleotide that codes for a protein. Coding sequences can also be referred to as open reading frames. The region or sequence is bounded nearer the 5′ end by a start codon and nearer the 3′ end with a stop codon. Stop codons useful with the base editors described herein include the following;
CAG → TAG Stop codon
CAA → TAA
By “complex” is meant a combination of two or more molecules whose interaction relies on inter-molecular forces. Non-limiting examples of inter-molecular forces include covalent and non-covalent interactions. Non-limiting examples of non-covalent interactions include hydrogen bonding, ionic bonding, halogen bonding, hydrophobic bonding, van der Waals interactions (e.g., dipole-dipole interactions, dipole-induced dipole interactions, and London dispersion forces), and a-effects. In an embodiment, a complex comprises polypeptides, polynucleotides, or a combination of one or more polypeptides and one or more polynucleotides. In one embodiment, a complex comprises one or more polypeptides that associate to form a base editor (e.g., base editor comprising a nucleic acid programmable DNA binding protein, such as Cas9, and a deaminase) and a polynucleotide (e.g., a guide RNA). In an embodiment, the complex is held together by hydrogen bonds. It should be appreciated that one or more components of a base editor (e.g., a deaminase, or a nucleic acid programmable DNA binding protein) may associate covalently or non covalently. As one example, a base editor may include a deaminase covalently linked to a nucleic acid programmable DNA binding protein (e.g., by a peptide bond).
Alternatively, a base editor may include a deaminase and a nucleic acid programmable DNA binding protein that associate noncovalently (e.g., where one or more components of the base editor are supplied in trans and associate directly or via another molecule such as a protein or nucleic acid). In an embodiment, one or more components of the complex are held together by hydrogen bonds.
By “cytosine” or “4-Aminopyrimidin-2(1H)-one” is meant a purine nucleobase with the molecular formula C4H5N3O, having the structure
and corresponding to CAS No. 71-30-7.
By “cytidine” is meant a cytosine molecule attached to a ribose sugar via a glycosidic bond, having the structure
and corresponding to CAS No. 65-46-3. Its molecular formula is C9H13N3O5.
By “Cytidine Base Editor (CBE)” is meant a base editor comprising a cytidine deaminase.
By “Cytidine Base Editor (CBE) polynucleotide” is meant a polynucleotide encoding a CBE.
By “cytidine deaminase” or “cytosine deaminase” is meant a polypeptide or fragment thereof capable of deaminating cytidine or cytosine. In embodiments, the cytidine or cytosine is present in a polynucleotide. In one embodiment, the cytidine deaminase converts cytosine to uracil or 5-methylcytosine to thymine. The terms “cytidine deaminase” and “cytosine deaminase” are used interchangeably throughout the application. Petromyzon marinus cytosine deaminase 1 (PmCDA1) (SEQ ID NO: 13-14), Activation-induced cytidine deaminase (AICDA) (SEQ ID NOs: 15-21), and APOBEC (SEQ ID NOs: 12-61) are exemplary cytidine deaminases. Further exemplary cytidine deaminase (CDA) sequences are provided in the Sequence Listing as SEQ ID NOs: 62-66 and SEQ ID NOs: 67-189. Non-limiting examples of cytidine deaminases include those described in PCT/US20/16288, PCT/US2018/021878, 180802-021804/PCT, PCT/US2018/048969, and PCT/US2016/058344.By “cytosine deaminase activity” is meant catalyzing the deamination of cytosine or cytidine. In one embodiment, a polypeptide having cytosine deaminase activity converts an amino group to a carbonyl group. In an embodiment, a cytosine deaminase converts cytosine to uracil (i.e., C to U) or 5-methylcytosine to thymine (i.e., 5mC to T). In some embodiments, a cytosine deaminase as provided herein has increased cytosine deaminase activity (e.g., at least 10-fold, 20-fold, 30-fold, 40-fold. 50-fold, 60-fold, 70-fold, 80-fold, 90-fold, 100-fold or more) relative to a reference cytosine deaminase.
The term “deaminase” or “deaminase domain,” as used herein, refers to a protein or fragment thereof that catalyzes a deamination reaction.
“Detect” refers to identifying the presence, absence or amount of the analyte to be detected. In one embodiment, a sequence alteration in a polynucleotide or polypeptide is detected. In another embodiment, the presence of indels is detected.
By “detectable label” is meant a composition that when linked to a molecule of interest renders the latter detectable, via spectroscopic, photochemical, biochemical, immunochemical, or chemical means. For example, useful labels include radioactive isotopes, magnetic beads, metallic beads, colloidal particles, fluorescent dyes, electron-dense reagents, enzymes (for example, as commonly used in an enzyme linked immunosorbent assay (ELISA)), biotin, digoxigenin, or haptens.
By “dual editing activity” or “dual deaminase activity” is meant having adenosine deaminase and cytidine deaminase activity. In one embodiment, a base editor having dual editing activity has both A→G and C→T activity, wherein the two activities are approximately equal or are within about 10% or 20% of each other. In another embodiment, a dual editor has A→G activity that no more than about 10% or 20% greater than C→T activity. In another embodiment, a dual editor has A→G activity that is no more than about 10% or 20% less than C→T activity. In some embodiments, the adenosine deaminase variant has predominantly cytosine deaminase activity, and little, if any, adenosine deaminase activity. In some embodiments, the adenosine deaminase variant has cytosine deaminase activity, and no significant or no detectable adenosine deaminase activity.
The term “exonuclease” refers to a protein or polypeptide capable of removing successive nucleotides from either the 5′ or 3′ end of a polynucleotide.
The term “endonuclease” refers to a protein or polypeptide capable of catalyzing the cleavage of internal regions in a polynucleotide.
By “fragment” is meant a portion of a polypeptide or nucleic acid molecule. This portion contains, at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the entire length of the reference nucleic acid molecule or polypeptide. A fragment may contain 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100, 200, 300, 400, 500, 600, 700, 800, 900, or 1000 nucleotides or amino acids. In some embodiments, the fragment is a functional fragment. By “guide polynucleotide” is meant a polynucleotide or polynucleotide complex which is specific for a target sequence and can form a complex with a polynucleotide programmable nucleotide binding domain protein (e.g., Cas9 or Cpf1). In an embodiment, the guide polynucleotide is a guide RNA (gRNA). gRNAs can exist as a complex of two or more RNAs, or as a single RNA molecule.
By “heterologous,” or “exogenous” is meant a polynucleotide or polypeptide that 1) has been experimentally incorporated to a polynucleotide or polypeptide sequence to which the polynucleotide or polypeptide is not normally found in nature; or 2) has been experimentally placed into a cell that does not normally comprise the polynucleotide or polypeptide. In some embodiments, “heterologous” means that a polynucleotide or polypeptide has been experimentally placed into a non-native context. In some embodiments, a heterologous polynucleotide or polypeptide is derived from a first species or host organism, and is incorporated into a polynucleotide or polypeptide derived from a second species or host organism. In some embodiments, the first species or host organism is different from the second species or host organism. In some embodiments the heterologous polynucleotide is DNA. In some embodiments the heterologous polynucleotide is RNA.
“Hybridization” means hydrogen bonding, which may be Watson-Crick, Hoogsteen or reversed Hoogsteen hydrogen bonding, between complementary nucleobases. For example, adenine and thymine are complementary nucleobases that pair through the formation of hydrogen bonds.
By “increases” is meant a positive alteration of at least 10%, 25%, 50%, 75%, or 100%, or about 1.5 fold, about 2 fold, about 3-fold, about 4-fold, about 5-fold, about 6-fold, about 7-fold, about 8-fold, about 9-fold, about 10-fold, about 15-fold, about 20-fold, about 25-fold, about 30-fold, about 35-fold, about 40-fold, about 45-fold, about 50-fold, or about 100-fold.
The terms “inhibitor of base repair”. “base repair inhibitor”, “IBR” or their grammatical equivalents refer to a protein that is capable in inhibiting the activity of a nucleic acid repair enzyme, for example a base excision repair enzyme.
The terms “isolated,” “purified,” or “biologically pure” refer to material that is free to varying degrees from components which normally accompany it as found in its native state. “Isolate” denotes a degree of separation from original source or surroundings. “Purify” denotes a degree of separation that is higher than isolation. A “purified” or “biologically pure” protein is sufficiently free of other materials such that any impurities do not materially affect the biological properties of the protein or cause other adverse consequences. That is, a nucleic acid or peptide of this invention is purified if it is substantially free of cellular material, viral material, or culture medium when produced by recombinant DNA techniques, or chemical precursors or other chemicals when chemically synthesized. Purity and homogeneity are typically determined using analytical chemistry techniques, for example, polyacrylamide gel electrophoresis or high performance liquid chromatography. The term “purified” can denote that a nucleic acid or protein gives rise to essentially one band in an electrophoretic gel. For a protein that can be subjected to modifications, for example, phosphorylation or glycosylation, different modifications may give rise to different isolated proteins, which can be separately purified.
By “isolated polynucleotide” is meant a nucleic acid molecule that is free of the genes which, in the naturally-occurring genome of the organism from which the nucleic acid molecule of the invention is derived, flank the gene. The term therefore includes, for example, a recombinant DNA that is incorporated into a vector; into an autonomously replicating plasmid or virus, or into the genomic DNA of a prokaryote or eukaryote; or that exists as a separate molecule (for example, a cDNA or a genomic or cDNA fragment produced by PCR or restriction endonuclease digestion) independent of other sequences. In addition, the term includes an RNA molecule that is transcribed from a DNA molecule, as well as a recombinant DNA that is part of a hybrid gene encoding additional polypeptide sequence.
By an “isolated polypeptide” is meant a polypeptide of the invention that has been separated from components that naturally accompany it. Typically, the polypeptide is isolated when it is at least 60%, by weight, free from the proteins and naturally-occurring organic molecules with which it is naturally associated. Preferably, the preparation is at least 75%, more preferably at least 90%, and most preferably at least 99%, by weight, a polypeptide of the invention. An isolated polypeptide of the invention may be obtained, for example, by extraction from a natural source, by expression of a recombinant nucleic acid encoding such a polypeptide; or by chemically synthesizing the protein. Purity can be measured by any appropriate method, for example, column chromatography, polyacrylamide gel electrophoresis, or by HPLC analysis.
The term “linker”, as used herein, refers to a molecule that links two moieties. In one embodiment, the term “linker” refers to a covalent linker (e.g., covalent bond) or a non-covalent linker.
By “marker” is meant any protein or polynucleotide having an alteration in expression, level, structure, or activity that is associated with a disease or disorder.
The term “mutation,” as used herein, refers to a substitution of a residue within a sequence, e.g., a nucleic acid or amino acid sequence, with another residue, or a deletion or insertion of one or more residues within a sequence. Mutations are typically described herein by identifying the original residue followed by the position of the residue within the sequence and by the identity of the newly substituted residue. Various methods for making the amino acid substitutions (mutations) provided herein are well known in the art, and are provided by, for example, Green and Sambrook, Molecular Cloning: A Laboratory Manual (4th ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (2012)).
The terms “nucleic acid” and “nucleic acid molecule,” as used herein, refer to a compound comprising a nucleobase and an acidic moiety. e.g., a nucleoside, a nucleotide, or a polymer of nucleotides. Typically, polymeric nucleic acids, e.g., nucleic acid molecules comprising three or more nucleotides are linear molecules, in which adjacent nucleotides are linked to each other via a phosphodiester linkage. In some embodiments, “nucleic acid” refers to individual nucleic acid residues (e.g. nucleotides and/or nucleosides). In some embodiments, “nucleic acid” refers to an oligonucleotide chain comprising three or more individual nucleotide residues. As used herein, the terms “oligonucleotide” and “polynucleotide” can be used interchangeably to refer to a polymer of nucleotides (e.g., a string of at least three nucleotides). In some embodiments, “nucleic acid” encompasses RNA as well as single and/or double-stranded DNA. Nucleic acids may be naturally occurring, for example, in the context of a genome, a transcript, an mRNA, tRNA, rRNA, siRNA, snRNA, a plasmid, cosmid, chromosome, chromatid, or other naturally occurring nucleic acid molecule. On the other hand, a nucleic acid molecule may be a non-naturally occurring molecule. e.g., a recombinant DNA or RNA, an artificial chromosome, an engineered genome, or fragment thereof, or a synthetic DNA, RNA, DNA/RNA hybrid, or including non-naturally occurring nucleotides or nucleosides. Furthermore, the terms “nucleic acid,” “DNA,” “RNA,” and/or similar terms include nucleic acid analogs, e.g., analogs having other than a phosphodiester backbone. Nucleic acids can be purified from natural sources, produced using recombinant expression systems and optionally purified, chemically synthesized, etc. Where appropriate, e.g., in the case of chemically synthesized molecules, nucleic acids comprise nucleoside analogs such as analogs having chemically modified bases or sugars, and backbone modifications. A nucleic acid sequence is presented in the 5′ to 3′ direction unless otherwise indicated. In some embodiments, a nucleic acid is or comprises natural nucleosides (e.g. adenosine, thymidine, guanosine, cytidine, uridine, deoxyadenosine, deoxythymidine, deoxyguanosine, and deoxycytidine): nucleoside analogs (e.g., 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3-methyl adenosine, 5-methylcytidine, 2-aminoadenosine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-propynyl-uridine, C5-propynyl-cytidine, C5-methylcytidine, 2-aminoadenosine, 7-deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, 0(6)-methylguanine, and 2-thiocytidine); chemically modified bases; biologically modified bases (e.g., methylated bases); intercalated bases; modified sugars (2′-e.g., fluororibose, ribose, 2′-deoxyribose, arabinose, and hexose); and/or modified phosphate groups (e.g., phosphorothioates and 5′-N-phosphoramidite linkages).
The term “nuclear localization sequence,” “nuclear localization signal,” or “NLS” refers to an amino acid sequence that promotes import of a protein into the cell nucleus. Nuclear localization sequences are known in the art and described, for example, in Plank et al., International PCT application, PCT/EP2000/011690, filed Nov. 23, 2000, published as WO/2001/038547 on May 31, 2001, the contents of which are incorporated herein by reference for their disclosure of exemplary nuclear localization sequences. In other embodiments, the NLS is an optimized NLS described, for example, by Koblan et al., Nature Biotech. 2018 doi:10.1038/nbt.4172. In some embodiments, an NLS comprises the amino acid sequence
The term “nucleobase,” “nitrogenous base,” or “base,” used interchangeably herein, refers to a nitrogen-containing biological compound that forms a nucleoside, which in turn is a component of a nucleotide. The ability of nucleobases to form base pairs and to stack one upon another leads directly to long-chain helical structures such as ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Five nucleobases—adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U)—are called primary or canonical. Adenine and guanine are derived from purine, and cytosine, uracil, and thymine are derived from pyrimidine. DNA and RNA can also contain other (non-primary) bases that are modified. Non-limiting exemplary modified nucleobases can include hypoxanthine, xanthine, 7-methylguanine, 5,6-dihydrouracil, 5-methylcytosine (m5C), and 5-hydromethylcytosine. Hypoxanthine and xanthine can be created through mutagen presence, both of them through deamination (replacement of the amine group with a carbonyl group). Hypoxanthine can be modified from adenine. Xanthine can be modified from guanine. Uracil can result from deamination of cytosine. A “nucleoside” consists of a nucleobase and a five carbon sugar (either ribose or deoxyribose). Examples of a nucleoside include adenosine, guanosine, uridine, cytidine, 5-methyluridine (m5U), deoxyadenosine, deoxyguanosine, thymidine, deoxyuridine, and deoxycytidine. Examples of a nucleoside with a modified nucleobase includes inosine (I), xanthosine (X), 7-methylguanosine (m7G), dihydrouridine (D), 5-methylcytidine (m5C), and pseudouridine (Ψ). A “nucleotide” consists of a nucleobase, a five carbon sugar (either ribose or deoxyribose), and at least one phosphate group. Non-limiting examples of modified nucleobases and/or chemical modifications that a modified nucleobase may include are the following: pseudo-uridine, 5-Methyl-cytosine, 2′-O-methyl-3′-phosphonoacetate. 2′-O-methyl thioPACE (MSP), 2′-O-methyl-PACE (MP), 2′-fluoro RNA (2′-F-RNA), constrained ethyl (S-cEt), 2′-O-methyl (‘M’), 2′-O-methyl-3′-phosphorothioate (‘MS’), 2′-O-methyl-3′-thiophosphonoacetate (‘MSP’), 5-methoxyuridine, phosphorothioate, and N1-Methylpseudouridine.
The term “nucleic acid programmable DNA binding protein” or “napDNAbp” may be used interchangeably with “polynucleotide programmable nucleotide binding domain” to refer to a protein that associates with a nucleic acid (e.g., DNA or RNA), such as a guide nucleic acid or guide polynucleotide (e.g., gRNA), that guides the napDNAbp to a specific nucleic acid sequence. In some embodiments, the polynucleotide programmable nucleotide binding domain is a polynucleotide programmable DNA binding domain. In some embodiments, the polynucleotide programmable nucleotide binding domain is a polynucleotide programmable RNA binding domain. In some embodiments, the polynucleotide programmable nucleotide binding domain is a Cas9 protein. A Cas9 protein can associate with a guide RNA that guides the Cas9 protein to a specific DNA sequence that is complementary to the guide RNA. In some embodiments, the napDNAbp is a Cas9 domain, for example a nuclease active Cas9, a Cas9 nickase (nCas9), or a nuclease inactive Cas9 (dCas9). Non-limiting examples of nucleic acid programmable DNA binding proteins include, Cas9 (e.g., dCas9 and nCas9), Cas12a/Cpf1, Cas12b/C2c1, Cas12c/C2c3, Cas12d/CasY, Cas12e/CasX, Cas12g, Cas12h, Cas12i, and Cas12j/CasΦ (Cas12j/Casphi). Non-limiting examples of Cas enzymes include Cas1, Cas1B, Cas2, Cas3, Cas4, Cas5, Cas5d, Cas5t, Cas5h, Cas5a, Cas6, Cas7, Cas8, Cas8a, Cas8b, Cas8c. Cas9 (also known as Csn1 or Csx12), Cas10, Cas10d, Cas12a/Cpf1, Cas12b/C2c1, Cas12c/C2c3, Cas12d/CasY, Cas12e/CasX, Cas12g, Cas12h, Cas12i, Cas12j/Cas4, Cpf1, Csy1, Csy2, Csy3, Csy4, Cse1, Cse2, Cse3, Cse4, Cse5e, Csc1, Csc2, Csa5, Csn1, Csn2, Csm1, Csm2, Csm3, Csm4, Csm5, Csm6, Cmr1, Cmr3, Cmr4, Cmr5, Cmr6, Csb1, Csb2, Csb3, Csx17, Csx14, Csx10, Csx16, CsaX, Csx3, Csx1, Csx1S, Csx11, Csf1, Csf2, CsO, Csf4, Csd1, Csd2, Cst1, Cst2, Csh1, Csh2, Csa1, Csa2, Csa3, Csa4, Csa5, Type II Cas effector proteins, Type V Cas effector proteins, Type VI Cas effector proteins, CARF, DinG, homologues thereof, or modified or engineered versions thereof. Other nucleic acid programmable DNA binding proteins are also within the scope of this disclosure, although they may not be specifically listed in this disclosure. See, e.g., Makarova et al. “Classification and Nomenclature of CRISPR-Cas Systems: Where from Here?” CRISPR J. 2018 October:1:325-336. doi. 10.1089/crispr.2018.0033; Yan et al., “Functionally diverse type V CRISPR-Cas systems” Science. 2019 Jan. 4:363(6422):88-91. doi: 10.1126/science.aav7271, the entire contents of each are hereby incorporated by reference. Exemplary nucleic acid programmable DNA binding proteins and nucleic acid sequences encoding nucleic acid programmable DNA binding proteins are provided in the Sequence Listing as SEQ ID NOs: 197-230, and 378.
The terms “nucleobase editing domain” or “nucleobase editing protein,” as used herein, refers to a protein or enzyme that can catalyze a nucleobase modification in RNA or DNA, such as cytosine (or cytidine) to uracil (or uridine) or thymine (or thymidine), and adenine (or adenosine) to hypoxanthine (or inosine) deaminations, as well as non-templated nucleotide additions and insertions. In some embodiments, the nucleobase editing domain is a deaminase domain (e.g., an adenine deaminase or an adenosine deaminase; or a cytidine deaminase or a cytosine deaminase).
As used herein, “obtaining” as in “obtaining an agent” includes synthesizing, purchasing, or otherwise acquiring the agent.
By “subject” or “patient” is meant a mammal, including, but not limited to, a human or non-human mammal. In embodiments, the mammal is a bovine, equine, canine, ovine, rabbit, rodent, nonhuman primate, or feline. In an embodiment, “patient” refers to a mammalian subject with a higher than average likelihood of developing a disease or a disorder. Exemplary patients can be humans, non-human primates, cats, dogs, pigs, cattle, cats, horses, camels, llamas, goats, sheep, rodents (e.g., mice, rabbits, rats, or guinea pigs) and other mammalians that can benefit from the therapies disclosed herein. Exemplary human patients can be male and/or female.
The terms “protein”, “peptide”, “polypeptide”, and their grammatical equivalents are used interchangeably herein, and refer to a polymer of amino acid residues linked together by peptide (amide) bonds. A protein, peptide, or polypeptide can be naturally occurring, recombinant, or synthetic, or any combination thereof.
The term “fusion protein” as used herein refers to a hybrid polypeptide which comprises protein domains from at least two different proteins.
The term “recombinant” as used herein in the context of proteins or nucleic acids refers to proteins or nucleic acids that do not occur in nature, but are the product of human engineering. For example, in some embodiments, a recombinant protein or nucleic acid molecule comprises an amino acid or nucleotide sequence that comprises at least one, at least two, at least three, at least four, at least five, at least six, or at least seven mutations as compared to any naturally occurring sequence.
By “reduces” is meant a negative alteration of at least 10%, 25%, 50%, 75%, or 100%.
By “reference” is meant a standard or control condition. In one embodiment, the reference is a wild-type or healthy cell. In other embodiments and without limitation, a reference is an untreated cell that is not subjected to a test condition, or is subjected to placebo or normal saline, medium, buffer, and/or a control vector that does not harbor a polynucleotide of interest.
A “reference sequence” is a defined sequence used as a basis for sequence comparison. A reference sequence may be a subset of or the entirety of a specified sequence; for example, a segment of a full-length cDNA or gene sequence, or the complete cDNA or gene sequence. For polypeptides, the length of the reference polypeptide sequence will generally be at least about 16 amino acids, at least about 20 amino acids, at least about 25 amino acids, about 35 amino acids, about 50 amino acids, or about 100 amino acids. For nucleic acids, the length of the reference nucleic acid sequence will generally be at least about 50 nucleotides, at least about 60 nucleotides, at least about 75 nucleotides, about 100 nucleotides or about 300 nucleotides or any integer thereabout or therebetween. In some embodiments, a reference sequence is a wild-type sequence of a protein of interest. In other embodiments, a reference sequence is a polynucleotide sequence encoding a wild-type protein.
The term “RNA-programmable nuclease,” and “RNA-guided nuclease” refer to a nuclease that forms a complex with (e.g., binds or associates with) one or more RNA(s) that is not a target for cleavage. In some embodiments, an RNA-programmable nuclease, when in a complex with an RNA, may be referred to as a nuclease-RNA complex. Typically, the bound RNA(s) is referred to as a guide RNA (gRNA). In some embodiments, the RNA-programmable nuclease is the (CRISPR-associated system) Cas9 endonuclease, for example. Cas9 (Csn1) from Streptococcus pyogenes (e.g., SEQ ID NO: 197), Cas9 from Neisseria meningitidis (NmeCas9; SEQ ID NO: 208), Nme2Cas9 (SEQ ID NO: 209), Streptococcus constellatus (ScoCas9), or derivatives thereof (e.g. a sequence with at least about 85% sequence identity to a Cas9, such as Nme2Cas9 or spCas9).
The term “single nucleotide polymorphism (SNP)” is a variation in a single nucleotide that occurs at a specific position in the genome, where each variation is present to some appreciable degree within a population (e.g., >1%). SNPs can fall within coding regions of genes, non-coding regions of genes, or in the intergenic regions (regions between genes). In some embodiments, SNPs within a coding sequence do not necessarily change the amino acid sequence of the protein that is produced, due to degeneracy of the genetic code. SNPs in the coding region are of two types: synonymous and nonsynonymous SNPs. Synonymous SNPs do not affect the protein sequence, while nonsynonymous SNPs change the amino acid sequence of protein. The nonsynonymous SNPs are of two types: missense and nonsense. SNPs that are not in protein-coding regions can still affect gene splicing, transcription factor binding, messenger RNA degradation, or the sequence of noncoding RNA. Gene expression affected by this type of SNP is referred to as an eSNP (expression SNP) and can be upstream or downstream from the gene. A single nucleotide variant (SNV) is a variation in a single nucleotide without any limitations of frequency and can arise in somatic cells. A somatic single nucleotide variation can also be called a single-nucleotide alteration.
By “specifically binds” is meant a nucleic acid molecule, polypeptide, polypeptide/polynucleotide complex, compound, or molecule that recognizes and binds a polypeptide and/or nucleic acid molecule of the invention, but which does not substantially recognize and bind other molecules in a sample, for example, a biological sample.
By “substantially identical” is meant a polypeptide or nucleic acid molecule exhibiting at least 50% identity to a reference amino acid sequence. In one embodiment, a reference sequence is a wild-type amino acid or nucleic acid sequence. In another embodiment, a reference sequence is any one of the amino acid or nucleic acid sequences described herein. In one embodiment, such a sequence is at least about 60%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or even 99.99%, identical at the amino acid level or nucleic acid level to the sequence used for comparison.
Sequence identity is typically measured using sequence analysis software (for example, Sequence Analysis Software Package of the Genetics Computer Group, University of Wisconsin Biotechnology Center, 1710 University Avenue, Madison, Wis. 53705, BLAST, BESTFIT, GAP, or PILEUP/PRETTYBOX programs). Such software matches identical or similar sequences by assigning degrees of homology to various substitutions, deletions, and/or other modifications. Conservative substitutions typically include substitutions within the following groups; glycine, alanine; valine, isoleucine, leucine; aspartic acid, glutamic acid, asparagine, glutamine; serine, threonine; lysine, arginine; and phenylalanine, tyrosine.
Nucleic acid molecules useful in the methods of the invention include any nucleic acid molecule that encodes a polypeptide of the invention or a functional fragment thereof. Such nucleic acid molecules need not be 100% identical with an endogenous nucleic acid sequence, but will typically exhibit substantial identity. Polynucleotides having “substantial identity” to an endogenous sequence are typically capable of hybridizing with at least one strand of a double-stranded nucleic acid molecule. Nucleic acid molecules useful in the methods of the invention include any nucleic acid molecule that encodes a polypeptide of the invention or a functional fragment thereof. Such nucleic acid molecules need not be 100% identical with an endogenous nucleic acid sequence, but will typically exhibit substantial identity. Polynucleotides having “substantial identity” to an endogenous sequence are typically capable of hybridizing with at least one strand of a double-stranded nucleic acid molecule. By “hybridize” is meant pair to form a double-stranded molecule between complementary polynucleotide sequences (e.g., a gene described herein), or portions thereof, under various conditions of stringency. (See, e.g., Wahl, G. M. and S. L. Berger (1987) Methods Enzymol. 152:399; Kimmel, A. R. (1987) Methods Enzymol. 152:507).
By “split” is meant divided into two or more fragments.
A “split Cas9 protein” or “split Cas9” refers to a Cas9 protein that is provided as an N-terminal fragment and a C-terminal fragment encoded by two separate nucleotide sequences. The polypeptides corresponding to the N-terminal portion and the C-terminal portion of the Cas9 protein may be spliced to form a “reconstituted” Cas9 protein.
The term “target site” refers to a nucleotide sequence or nucleobase of interest within a nucleic acid molecule that is modified. In embodiments, the modification is deamination of a base. The deaminase can be a cytidine or an adenine deaminase. The fusion protein or base editing complex comprising a deaminase may comprise a dCas9-adenosine deaminase fusion protein, a Cas12b-adenosine deaminase fusion, or a base editor disclosed herein.
By “uracil glycosylase inhibitor” or “UGI” is meant an agent that inhibits the uracil-excision repair system. Base editors comprising a cytidine deaminase convert cytosine to uracil, which is then converted to thymine through DNA replication or repair. In various embodiments, a uracil DNA glycosylase (UGI) prevent base excision repair which changes the U back to a C.
In some instances, contacting a cell and/or polynucleotide with a UGI and a base editor prevents base excision repair which changes the U back to a C. An exemplary UGI comprises an amino acid sequence as follows:
In some embodiments, the agent inhibiting the uracil-excision repair system is a uracil stabilizing protein (USP). See, e.g., WO 2022015969 A1, incorporated herein by reference.
As used herein, the term “vector” refers to a means of introducing a nucleic acid sequence into a cell, resulting in a transformed cell. Vectors include plasmids, transposons, phages, viruses, liposomes, lipid nanoparticles, and episomes.
Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50.
The recitation of a listing of chemical groups in any definition of a variable herein includes definitions of that variable as any single group or combination of listed groups. The recitation of an embodiment for a variable or aspect herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.
All terms are intended to be understood as they would be understood by a person skilled in the art. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure pertains
In this application, the use of the singular includes the plural unless specifically stated otherwise. It must be noted that, as used in the specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. In this application, the use of “or” means “and/or” unless stated otherwise. Furthermore, use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting.
As used in this specification and claim(s), the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. Any embodiments specified as “comprising” a particular component(s) or element(s) are also contemplated as “consisting of” or “consisting essentially of” the particular component(s) or element(s) in some embodiments. It is contemplated that any embodiment discussed in this specification can be implemented with respect to any method or composition of the present disclosure, and vice versa. Furthermore, compositions of the present disclosure can be used to achieve methods of the present disclosure.
The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system.
Reference in the specification to “some embodiments,” “an embodiment,” “one embodiment” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the present disclosures.
Pseudotyped Recombinant Rabies Virus with Chimeric Envelope Proteins
Provided herein are pseudotyped recombinant rabies virus (RABV) particles comprising a chimeric envelope protein that are useful for transducing a target cell. In one aspect, a pseudotyped RABV particle of the present disclosure comprises a recombinant RABV genome, wherein the recombinant RABV genome comprises a nucleic acid comprising a therapeutic transgene. As such, pseudotyped RABV particles of the present disclosure can be employed in a method for transducing a target cell. Upon transduction of a target cell, the transgene comprised within the recombinant RABV genome is expressed and a transgene product is produced. While RABV particles have a natural tropism for neuronal cell types, the pseudotyped recombinant RABV particles described herein adopt the tropism of the pseudotyping (i.e., chimeric) envelope protein. As such, the pseudotyped recombinant RABV particles described herein can exhibit tropism for neuronal as well as non-neuronal cell types, and find use in delivering a transgene to a wide variety of cell types.
The chimeric envelope proteins described herein comprise a non-RABV envelope protein ectodomain and a non-RABV envelope protein transmembrane domain while retaining the RABV C terminal domain (CTD), also known as the cytoplasmic domain. These chimeric envelop proteins are capable of functioning in a RABV particle at least in part though the retention of the RABV CTD. The presence of the RABV CTD enhances the pseudotyping capacity of the envelope proteins (i.e., glycoproteins), and multiple RABV chimeric envelope proteins pseudotyped better than wild-type envelope proteins. The use of the RABV CTD enhanced pseudotyping for non-lyssavirus derived envelope proteins (e.g., ephemerovirus and tibrovirus) that would not otherwise generate infectious viral particles, thereby expanding the tropism beyond RABV.
In certain embodiments, the chimeric envelope protein retains target receptor binding activity compared to a wild-type version of the non-RABV envelope protein.
In certain embodiments, the chimeric envelope protein retains target receptor binding activity and fusion activity compared to a wild-type version of the non-RABV envelope protein.
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 60% identity (e.g., about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 390 (RRVNRSEPTQHNLRGTGREVSVTPQSGKIISSWESHKSGGETRL). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 390 (RRVNRSEPTQHNLRGTGREVSVTPQSGKIISSWESHKSGGETRL).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 60% identity (e.g., about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 391 (RRANRPESKQRSFGGTGGNVSVTSQSGKVIPSWESYKSGGEIRL). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 391 (RRANRPESKQRSFGGTGGNVSVTSQSGKVIPSWESYKSGGEIRL).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 60% identity (e.g., about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 392 (KKGGRRNSPTNRPDLPIGLSTTPQPKSKVISSWESYKGTSNV). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 392 (KKGGRRNSPTNRPDLPIGLSTTPQPKSKVISSWESYKGTSNV).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 60% identity (e.g., about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 393 (GRVNRPKSTQRNLGGTERKVSVTSQSGKVISSWESYKSGGETRL). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 393 (GRVNRPKSTQRNLGGTERKVSVTSQSGKVISSWESYKSGGETRL).
In certain embodiments, the RABV C-terminal domain comprises an amino acid sequence with at least 60% identity (e.g., about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 394 (LRCRAGRNRRTIRSNHRSLSHDVVFHKDKDKVITSWESYKGQTAQ). In certain embodiments, the RABV C-terminal domain consists of an amino acid sequence SEQ ID NO: 394 (LRCRAGRNRRTIRSNHRSLSHDVVFHKDKDKVITSWESYKGQTAQ).
Also known as Rabies lyssavirus, rabies virus (RABV) is a negative sense single stranded RNA virus of the Lyssavirus genus of the Rhabdoviridae family. Rabies virus has a cylindrical morphology, and the structure includes a lipoprotein envelope composed of envelope protein G surrounding a helical ribonucleoprotein core. Like other lyssaviruses, the rabies virus genome contains five genes that encode for proteins that promote transcription and replication of the genome and proteins that make up the structural components of the virus. The five genes are: the N gene encoding for a rabies virus nucleoprotein: the P gene encoding for a rabies virus phosphoprotein; the M gene encoding for a rabies virus matrix protein; the G gene encoding for a rabies virus envelope protein (also known as the glycoprotein); and the L gene encoding for a rabies virus polymerase. Viral genome RNA and the nucleoprotein together form a ribonucleoprotein that functions as a template for replication and transcription by the rabies virus polymerase (an RNA-dependent RNA polymerase).
In certain embodiments, the recombinant RABV genome does not encode a envelope protein or a functional variant thereof (i.e., the RABV G gene is absent from the recombinant RABV genome). Recombinant RABV genomes that lack a G gene encoding for a RABV envelope protein prevents the virus from being able to endogenously produce envelope protein. Because the envelope protein is only required for the final steps of the viral life cycle, this deletion prevents the virus from spreading beyond initially infected cells, but it does not prevent the virus from completing the entirety of its replication cycle up to that point.
In certain embodiments, a recombinant RABV genome of the present disclosure has one or more additional RABV genes removed. For example, the N gene, the P gene, the M gene, and/or the L gene may be absent from the recombinant RABV genome. In certain embodiments, the recombinant RABV genome lacks an L gene encoding for a lyssavirus polymerase or a functional variant thereof. The L gene product is required both for transcription of viral genes and for replication of the viral genome, and deletion of the L gene may result in less cytotoxicity of a target transduced cell. See, e.g., Chatterjee et al., Nat. Neurosci. (2018) 21(4): 638-646, the disclosure of which is herein incorporated by reference in its entirety. In certain embodiments, the recombinant RABV genome lacks a G gene encoding for a RABV envelope protein or a functional variant thereof, and lacks an L gene encoding for a RABV polymerase or a functional variant thereof.
It is readily appreciated by those of ordinary skill in the art that a recombinant RABV genome that lacks a RABV gene, as described herein, refers to a RABV genome that lacks all or a portion of the RABV gene. For example, a recombinant RABV genome that lacks a G gene may lack all or a portion of the G gene, wherein the portion of the G gene is required for the function of the G gene product. In certain embodiments, lacking a portion of the G gene that is required for the function of the G gene product may result in the production of a truncated, non-functional envelope protein. In certain embodiments, a recombinant RABV genome that lacks an L gene may lack all or a portion of the L gene, wherein the portion of the L gene is required for the function of the L gene product. In certain embodiments, lacking a portion of the L gene that is required for the function of the L gene product may result in the production of a truncated, non-functional RNA-dependent RNA polymerase.
In certain embodiments, a recombinant RABV genome of the present disclosure encodes a nucleic acid comprising a transgene (e.g., a therapeutic transgene). In certain embodiments, the nucleic acid comprising a transgene replaces the one or more RABV genes that are removed, as described herein. For example, the nucleic acid comprising a transgene may replace all or a portion of a RABV gene. In certain embodiments, the nucleic acid comprising a transgene replaces all or a portion of a G gene, wherein the portion of the G gene is required for the function of the G gene product. In certain embodiments, the nucleic acid comprising a transgene replaces all or a portion of an L gene, wherein the portion of the L gene is required for the function of the L gene product. In certain embodiments, the nucleic acid comprising a transgene replaces all or a portion of an L gene, wherein the portion of the L gene is required for the function of the L gene product; and all or a portion of a G gene, wherein the portion of the G gene is required for the function of the G gene product.
In certain embodiments, a recombinant RABV genome of the present disclosure encodes a nucleic acid comprising a transgene, wherein the transgene replaces the one or more RABV genes that are removed, as described herein. In certain embodiments, the recombinant RABV genome comprises an N gene encoding for a RABV nucleoprotein or a functional variant thereof, a P gene encoding for a RABV phosphoprotein or a functional variant thereof, and/or an M gene encoding for a RABV matrix protein or a functional variant thereof.
As used herein, the term “chimeric envelope protein” refers to an envelope protein (i.e., a glycoprotein) that is made up of domains from separate and distinct viruses. In particular, the chimeric envelope protein comprises, from N-terminus to C-terminus, a non-RABV envelope protein ectodomain, a non-RABV envelope protein transmembrane domain, and a RABV C-terminal domain.
As used herein, the term “non-RABV envelope protein ectodomain” or “non-RABV extracellular domain” refers to an envelope protein ectodomain from a virus that is different from the natural envelope protein of the RABV particle (i.e., the envelope protein that is encoded by the RABV genome).
As used herein, the term “non-RABV envelope protein transmembrane domain” refers to an envelope protein transmembrane domain from a virus that is different from the natural envelope protein of the RABV particle (i.e., the envelope protein that is encoded by the RABV genome).
By way of example, but in no way limiting, a pseudotyped recombinant RABV particle comprises a chimeric envelope protein with a non-RABV envelope protein ectodomain and/or a non-RABV envelope protein transmembrane domain that is from any virus other than rabies virus (e.g., a pseudotyped recombinant RABV particle comprising a chimeric envelope protein with a Rhabdoviridae family envelope protein ectodomain and/or a Rhabdoviridae family envelope protein transmembrane domain).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain are from the same envelope protein (e.g., the envelope protein ectodomain and envelope protein transmembrane domain from bovine ephemeral fever virus (BEFV)). In other embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain are from different envelope proteins (e.g., the envelope protein ectodomain from BEFV and the envelope protein transmembrane domain from ekpoma virus 1 (EKV1)).
In certain embodiments, the non-RABV envelope protein ectodomain and/or the non-RABV envelope protein transmembrane domain are of a virus in the Rhabdoviridae family (with the exception of RABV, which is a part of the Rhabdoviridae family). The Rhabdoviridae family comprises several genera, including lyssavirus, tibrovirus, vesiculovirus, ephemerovirus, novirhabdovirus, perhabdovirus, sigmavirus, sprivivirus, and tupavirus. Rhabdoviruses belong to group V of the Baltimore classification of viruses, with a negative-sense, single-stranded RNA genome. The rhabdoviruses have a cylindrical morphology of about 75 nm wide and about 180 nm long.
In certain embodiments, the non-RABV envelope protein ectodomain and/or the non-RABV envelope protein transmembrane domain are not from a lyssavirus.
In certain embodiments, the Rhabdoviridae family virus comprises an ephemerovirus, a tibrovirus, an almendravirus, a novirhabdovirus, a tupavirus, or a moussa virus (MOUV).
In certain embodiments, the ephemerovirus is bovine ephemeral fever virus (BEFV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a BEFV amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 395
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 396
In certain embodiments, the tibrovirus is an ekpoma virus 1 (EKV1) or an ekpoma virus 2 (EKV2).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a EKV1 amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 397
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 90%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 398
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a EKV2 amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 399
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 400
In certain embodiments, the tibrovirus is a Bas-Congo tibrovirus (BASV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a BASV amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 401
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 402
In certain embodiments, the tibrovirus is a tibrogargan virus (TIBV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises a TIBV amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 403
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity (e.g., 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% identity) to SEQ ID NO: 404
In certain embodiments, the almendravirus is arboretum virus (ABTV) or balsa virus (BALV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an ABTV amino acid sequence comprising at least 90% identity to SEQ ID NO: 405
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 406
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an BALV amino acid sequence comprising at least 90% identity to SEQ ID NO: 407
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 408
In certain embodiments, the novirhabdovirus is viral hemorrhagic septicemia virus (VSHV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an VSHV amino acid sequence comprising at least 90% identity to SEQ ID NO. 409
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 410
In certain embodiments, the tupavirus is tupaia Virus (TUPV).
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an TUPV amino acid sequence comprising at least 90% identity to SEQ ID NO: 411
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 412
In certain embodiments, the non-RABV envelope protein ectodomain and the non-RABV envelope protein transmembrane domain comprises an MOUV amino acid sequence comprising at least 90% identity to SEQ ID NO: 413
In certain embodiments, the chimeric envelope protein comprises an amino acid sequence comprising at least 90% identity to SEQ ID NO: 414
In certain embodiments, a recombinant RABV genome of the present disclosure encodes a nucleic acid comprising a therapeutic transgene. As used herein, the term “therapeutic” refers to treatment and/or prophylaxis. As used herein, the term “therapeutic transgene” refers to a transgene that encodes a transgene product that is capable of effecting treatment and/or prophylaxis to a subject in need. In certain embodiments, the therapeutic effect is accomplished by suppression, remission, or eradication of a disease state suffered by the subject. The therapeutic transgene may encode any therapeutic agent that is capable of effecting treatment and/or prophylaxis in a subject in need, resulting in suppression, remission, or eradication of a disease state in the subject.
In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than: about 300 bp, about 400 bp, about 50) bp, about 600 bp, about 700 bp, about 800 bp, about 900 bp, about 1,000 bp, about 1,100 bp, about 1,200 bp, about 1,300 bp, about 1,400 bp, about 1.500 bp, about 1,600 bp, about 1,700 bp, about 1,800 bp, about 1,900 bp, about 2,000 bp, about 2,100 bp, about 2,200 bp, about 2,300 bp, about 2,400 bp, about 2,500 bp, about 2,600 bp, about 2,700 bp, about 2,800 bp, about 2,900 bp, or about 3,000 bp.
In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 300 bp (e.g., the therapeutic transgene is about 350 bp, about 400 bp, about 450 bp, about 500 bp, about 550 bp, about 600 bp, or about 650 bp). In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 650 bp (e.g., the therapeutic transgene is about 700 bp, about 750 bp, about 800 bp, about 850 bp, about 900 bp, about 950 bp, or about 1,000 bp). In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 1,000 bp (e.g., the therapeutic transgene is about 1,500 bp, about 2,000 bp, about 2,500 bp, or about 3,000 bp). In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 3,000 bp (e.g., the therapeutic transgene is about 3,500 bp, about 4,000 bp, or about 4,500 bp).
In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 4,500 bp (e.g., the therapeutic transgene is about 5,000 bp, about 5,500 bp, about 6,000 bp, about 6,500 bp, about 7,000 bp, about 7,500 bp, about 8,000 bp, or about 8,500 bp).
In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 8,500 bp (e.g., the therapeutic transgene is about 9,000 bp, about 9,500 bp, or about 10,000 bp).
In certain embodiments, the nucleic acid encoding the therapeutic transgene is greater than about 10,000 bp (e.g., the therapeutic transgene is about 10,500 bp, about 11,000 bp, about 11,500 bp, about 12,000 bp, about 12,500 bp, about 13,000 bp, about 13,500 bp, about 14,000 bp, about 14,500 bp, or about 15,000 bp).
In certain embodiments, the nucleic acid encoding the therapeutic transgene is between about 4,000 bp and about 6,000 bp (e.g., the therapeutic transgene is about 4,000 bp, about 4,500 bp, about 5,000 bp, about 5,500 bp, or about 6,000 bp).
In certain embodiments, the therapeutic transgene encodes a therapeutic nucleic acid. The therapeutic transgene may encode any therapeutic nucleic acid known in the art, for example, without limitation, any antisense RNA (single-stranded RNA), any small interfering RNA (double-stranded RNA), any RNA aptamer, and/or any messenger RNA (mRNA). For example, the therapeutic transgene can encode, without limitation, a miRNA, a miRNA mimic, a siRNA, a shRNA, a gRNA, a long noncoding RNA, an enhancer RNA, a RNA aptazyme, a RNA aptamer, an antagomiR, and/or a synthetic RNA. In certain embodiments, a therapeutic nucleic acid may be a RNA binding site, e.g., a miRNA binding site. Various other types of therapeutic nucleic acids are known to those of ordinary skill in the art.
In certain embodiments, the therapeutic transgene encodes a therapeutic polypeptide. The therapeutic transgene may encode any therapeutic polypeptide known in the art, for example, without limitation, a therapeutic polypeptide that can replace a deficient or abnormal protein: a therapeutic polypeptide that can augment an existing pathway; a therapeutic polypeptide that can provide a novel function or activity (e.g., a novel function or activity beneficial to a subject suffering from the lack thereof), a therapeutic polypeptide that interferes with a molecule or an organism (e.g., an organism that is different to the organism that hosts the target cell); and/or a therapeutic polypeptide that delivers other compounds or proteins (e.g., a radionuclide, a cytotoxic drug, and/or an effector protein). For example, the therapeutic transgene can encode, without limitation, a nucleic acid editing protein (e.g., an adenine or cytidine base editor) or system, an antibody or antibody-based drug, an anticoagulant, a blood factor, a bone morphogenetic protein, an engineered protein scaffold, an enzyme, an Fc fusion protein, a growth factor, a hormone, an interferon, an interleukin, and/or a thrombolytic. Various other types of therapeutic polypeptides are known to those of ordinary skill in the art.
In certain embodiments, the therapeutic transgene encodes a nucleic acid editing system or components thereof. In some embodiments the therapeutic transgene encodes a protein comprising a nucleic acid binding protein (e.g., a zinc finger, a TALE, or a nucleic acid programmable nucleic acid binding protein, such as Cas9). In some embodiments, the nucleic acid editing system component is a nucleic acid programmable nucleic acid binding protein (e.g., Cas9). In some embodiments, the nucleic acid editing system component is a guide RNA (gRNA).
In some embodiments, the therapeutic transgene encodes a CRISPR system. In some embodiments, the CRISPR system comprises a nucleobase editor comprising a polynucleotide programmable nucleotide binding domain and a nucleobase editing domain. In some embodiments, the nucleobase editing domain is an adenosine deaminase, cytidine deaminase, cytosine deaminase, or a functional variant thereof (e.g. a functional variant capable of deaminating a nucleobase in a nucleic acid molecule such as DNA or RNA). In some embodiments, the nucleobase editing domain is an adenosine deaminase. In some embodiments, the adenosine deaminase is ABE7.10. In some embodiments, the polynucleotide programmable nucleotide binding domain is a Cas9 polypeptide, a Cas12 polypeptide, or a functional variant thereof. In some embodiments, the CRISPR system further comprises a guide RNA (gRNA) or a nucleic acid encoding a gRNA.
In some embodiments the therapeutic transgene encodes a nucleobase modifying protein (e.g., a base editor protein). In some embodiments the therapeutic transgene encodes an adenosine base editor (e.g., ABE7.10). In some embodiments the therapeutic transgene encodes a cytidine base editor. In some embodiments the therapeutic transgene encodes a cytosine base editor capable of deaminating a cytosine in DNA or RNA.
In certain embodiments, the therapeutic transgene encodes a nucleic acid editing system, e.g., a base editor system further described herein.
It will be readily apparent to those of ordinary skill in the art that a recombinant RABV genome of the present disclosure described herein encodes a nucleic acid comprising a therapeutic transgene, wherein the therapeutic transgene encodes a therapeutic polypeptide and/or a therapeutic nucleic acid, e.g., in certain embodiments, the therapeutic transgene encodes a combination of the therapeutic polypeptide and the therapeutic nucleic acid. In certain embodiments, the therapeutic transgene encodes one or more therapeutic polypeptides. In certain embodiments, the therapeutic transgene encodes one or more therapeutic nucleic acids. In certain embodiments, the therapeutic transgene encodes a combination of one or more therapeutic polypeptides and one or more therapeutic nucleic acids. Delivery of a combination of a therapeutic polypeptide and therapeutic nucleic acid into a target cell may serve various purposes known to those of ordinary skill in the art. In certain embodiments, a therapeutic polypeptide may be delivered to a target cell, wherein the delivery is detargeted to certain other cell types. For example, a therapeutic transgene can encode a therapeutic polypeptide and/or therapeutic nucleic acid, and also comprise a miRNA binding site. The miRNA binding site may function for cell type detargeting. For example, miRNA122a, which is expressed exclusively in liver, can be employed for hepatocyte detargeting. See, e.g., Dhungel et al., Molecules (2018) 23(7): 1500.
In certain embodiments, the therapeutic transgene further encodes one or more reporter sequences. Reporter sequences when expressed in the target cell, produces a directly or an indirectly detectable signal. Examples of suitable reporter sequences include, without limitation, sequences encoding for fluorescent proteins (e.g., GFP, RFP, YFP), alkaline phosphatase, thymidine kinase, chloramphenicol acetyltransferase (CAT), luciferase, β-galactosidase (LacZ), and β-lactamase. Sequences encoding for cell surface membrane-bound proteins may also be suitable as reporter sequences, for example, membrane-bound proteins to which high affinity antibodies bind, e.g., influenza hemagglutinin protein (HA), CD2, CD4, CD8, and others known to those of ordinary skill in the art, including, e.g., membrane-bound proteins tagged with an antigen domain (e.g., an HA tag, a FLAG tag, a Myc tag, a polyhistidine tag).
In certain embodiments, the therapeutic transgene does not encode a reporter gene and/or a selectable marker. In certain embodiments, the therapeutic transgene does not encode a fluorescent reporter protein (e.g., GFP, YFP, RFP, tdTomato). In certain embodiments, the therapeutic transgene does not encode β-galactosidase (LacZ). In certain embodiments, the therapeutic transgene does not encode chloramphenicol acetyltransferase (CAT).
In certain embodiments, the therapeutic transgene doe not encode a polymerase (e.g., DNA polymerase, DNA-directed RNA polymerase, RNA-directed DNA polumerase (RT), telomerase).
In certain embodiments, the therapeutic transgene does not encode a site-specific recombinase (e.g., Cre, FLP, Hin, or Tre recombinases).
In certain embodiments, the therapeutic transgene does not encode a viral antigen.
In certain embodiments, the therapeutic transgene does not encode a pro-apoptotic protein (e.g., cytochrome c).
In certain embodiments, the therapeutic transgene does not encode an immunoglobulin (e.g., an immunoglobulin heavy and/or light chain.
In certain embodiments, a recombinant RABV genome of the present disclosure comprises a transcriptional regulatory element operably linked to the nucleic acid encoding a transgene. The transcriptional regulatory element is capable of controlling the expression of the transgene (e.g., expression of the encoded therapeutic polypeptide and/or nucleic acid) that is operably linked thereto. In certain embodiments, the transcriptional regulatory element comprises a transcription initiation signal. The transcription initiation signal can be endogenous or exogenous to RABV. In certain embodiments, the transcription initiation signal is a synthetic transcription initiation signal. In certain embodiments, the nucleic acid encoding a transgene is further operably linked to a transcription termination polyadenylation signal. The transcription termination polyadenylation signal can be endogenous or exogenous to the RABV. In certain embodiments, the transcription termination polyadenylation signal is a synthetic transcription termination polyadenylation signal. Examples of suitable transcription initiation signals and transcriptional termination polyadenylaton signals are known to those of ordinary skill in the art, and are described in, e.g., Albertini et al., Adv. Virus. Res. (2011) 79: 1-22; Ogino and Green, Viruses (2019) 11(6): 504; and Ogino and Green, Front. Microbiol. (2019) 10: 1490, the disclosures of which are herein incorporated by reference in their entireties.
A recombinant RABV genome of the present disclosure comprising a nucleic acid comprising a therapeutic transgene may further comprise any elements known to those of ordinary skill in the art that aid and/or enhance in the expression of the therapeutic transgene.
Recombinant RABV genomes of the present disclosure are incorporated into a pseudotyped recombinant RABV particle by methods described herein.
Useful in the methods and compositions described herein are nucleobase editors that edit, modify or alter a target nucleotide sequence of a polynucleotide. Nucleobase editors described herein typically include a polynucleotide programmable nucleotide binding domain and a nucleobase editing domain (e.g., adenosine deaminase, cytidine deaminase, or a dual deaminase). A polynucleotide programmable nucleotide binding domain, when in conjunction with a bound guide polynucleotide (e.g., gRNA), can specifically bind to a target polynucleotide sequence and thereby localize the base editor to the target nucleic acid sequence desired to be edited.
Polynucleotide programmable nucleotide binding domains bind polynucleotides (e.g., RNA, DNA). A polynucleotide programmable nucleotide binding domain of a base editor can itself comprise one or more domains (e.g., one or more nuclease domains). In some embodiments, the nuclease domain of a polynucleotide programmable nucleotide binding domain comprises an endonuclease or an exonuclease. An endonuclease can cleave a single strand of a double-stranded nucleic acid or both strands of a double-stranded nucleic acid molecule. In some embodiments, a nuclease domain of a polynucleotide programmable nucleotide binding domain can cut zero, one, or two strands of a target polynucleotide.
Non-limiting examples of a polynucleotide programmable nucleotide binding domain which can be incorporated into a base editor include a CRISPR protein-derived domain, a restriction nuclease, a meganuclease, TAL nuclease (TALEN), and a zinc finger nuclease (ZFN). In some embodiments, a base editor comprises a polynucleotide programmable nucleotide binding domain comprising a natural or modified protein or portion thereof which via a bound guide nucleic acid is capable of binding to a nucleic acid sequence during CRISPR (i.e., Clustered Regularly Interspaced Short Palindromic Repeats)-mediated modification of a nucleic acid. Such a protein is referred to herein as a “CRISPR protein.” Accordingly, disclosed herein is a base editor comprising a polynucleotide programmable nucleotide binding domain comprising all or a portion (e.g., a functional portion) of a CRISPR protein (i.e. a base editor comprising as a domain all or a portion (e.g., a functional portion) of a CRISPR protein, also referred to as a “CRISPR protein-derived domain” of the base editor). A CRISPR protein-derived domain incorporated into a base editor can be modified compared to a wild-type or natural version of the CRISPR protein. For example, as described below a CRISPR protein-derived domain can comprise one or more mutations, insertions, deletions, rearrangements and/or recombinations relative to a wild-type or natural version of the CRISPR protein.
Cas proteins that can be used herein include class 1 and class 2. Non-limiting examples of Cas proteins include Cas1, Cas1B, Cas2, Cas3, Cas4, Cas5, Cas5d, Cas5t, Cas5h, Cas5a, Cas6, Cas7, Cas8, Cas9 (also known as Csn1 or Csx12), Cas10, Csy1, Csy2, Csy3, Csy4, Cse1, Cse2, Cse3, Cse4, Cse5e, Csc1, Csc2, Csa5, Csn1, Csn2, Csm1, Csm2, Csm3, Csm4, Csm5, Csm6, Cmr1, Cmr3, Cmr4, Cmr5, Cmr6, Csb1, Csb2, Csb3, Csx17, Csx14, Csx10, Csx16, CsaX, Csx3, Csx1, Csx1S, Csf1, Csf2, CsO, Csf4, Csd1, Csd2, Cst1, Cst2, Csh1, Csh2, Csa1, Csa2, Csa3, Csa4, Csa5, Cas12a/Cpf1, Cas12b/C2c1 (e.g., SEQ ID NO: 232), Cas12c/C2c3, Cas12d/CasY, Cas12e/CasX, Cas12g, Cas12h, Cas12i, and Cas12j/CasΦ, CARF, DinG, homologues thereof, or modified versions thereof. A CRISPR enzyme can direct cleavage of one or both strands at a target sequence, such as within a target sequence and/or within a complement of a target sequence. For example, a CRISPR enzyme can direct cleavage of one or both strands within about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 50, 100, 200, 500, or more base pairs from the first or last nucleotide of a target sequence.
A vector that encodes a CRISPR enzyme that is mutated to with respect to a corresponding wild-type enzyme such that the mutated CRISPR enzyme lacks the ability to cleave one or both strands of a target polynucleotide containing a target sequence can be used. A Cas protein (e.g., Cas9, Cas12) or a Cas domain (e.g., Cas9, Cas12) can refer to a polypeptide or domain with at least or at least about 50%, 60%, 70%, 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity and/or sequence homology to a wild-type exemplary Cas polypeptide or Cas domain. Cas (e.g., Cas9, Cas12) can refer to the wild-type or a modified form of the Cas protein that can comprise an amino acid change such as a deletion, insertion, substitution, variant, mutation, fusion, chimera, or any combination thereof.
In some embodiments, a CRISPR protein-derived domain of a base editor can include all or a portion (e.g., a functional portion) of Cas9 from Corynebacterium ulcerans (NCBI Refs: NC_015683.1, NC_017317.1): Corynebacterium diphtheria (NCBI Refs: NC_016782.1, NC_016786.1): Spiroplasma syrphidicola (NCBI Ref: NC_021284.1): Prevotella intermedia (NCBI Ref: NC_017861.1): Spiroplasma taiwanense (NCBI Ref: NC_021846.1); Streptococcus iniae (NCBI Ref NC_021314.1); Belliella baltica (NCBI Ref: NC_018010.1): Psychroflexus torquis (NCBI Ref: NC_018721.1); Streptococcus thermophilus (NCBI Ref: YP_820832.1); Listeria innocua (NCBI Ref: NP_472073.1): Campylobacter jejuni (NCBI Ref: YP_002344900.1); Neisseria meningitidis (NCBI Ref: YP_002342100.1), Streptococcus pyogenes, or Staphylococcus aureus.
Cas9 nuclease sequences and structures are well known to those of skill in the art (See, e.g., “Complete genome sequence of an Ml strain of Streptococcus pyogenes.” Ferretti et al., Proc. Natl. Acad. Sci. U.S.A. 98:4658-4663(2001): “CRISPR RNA maturation by trans-encoded small RNA and host factor RNase III.” Deltcheva E., et al., Nature 471:602-607(2011); and “A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity.” Jinek M., et al., Science 337:816-821(2012), the entire contents of each of which are incorporated herein by reference). Cas9 orthologs have been described in various species, including, but not limited to, S. pyogenes and S. thermophilus. Additional suitable Cas9 nucleases and sequences will be apparent to those of skill in the art based on this disclosure, and such Cas9 nucleases and sequences include Cas9 sequences from the organisms and loci disclosed in Chylinski. Rhun, and Charpentier, “The tracrRNA and Cas9 families of type II CRISPR-Cas immunity systems” (2013) RNA Biology 10:5, 726-737: the entire contents of which are incorporated herein by reference.
Some aspects of the disclosure provide high fidelity Cas9 domains. High fidelity Cas9 domains are known in the art and described, for example, in Kleinstiver, B. P., et al. “High-fidelity CRISPR-Cas9 nucleases with no detectable genome-wide off-target effects.” Nature 529, 490-495 (2016); and Slaymaker. I. M., et al. “Rationally engineered Cas9 nucleases with improved specificity.” Science 351, 84-88 (2015), the entire contents of each of which are incorporated herein by reference. An Exemplary high fidelity Cas9 domain is provided in the Sequence Listing as SEQ ID NO: 233. In some embodiments, high fidelity Cas9 domains are engineered Cas9 domains comprising one or more mutations that decrease electrostatic interactions between the Cas9 domain and the sugar-phosphate backbone of a DNA, relative to a corresponding wild-type Cas9 domain. High fidelity Cas9 domains that have decreased electrostatic interactions with the sugar-phosphate backbone of DNA have less off-target effects. In some embodiments, the Cas9 domain (e.g., a wild type Cas9 domain (SEQ ID NOs: 197 and 200) comprises one or more mutations that decrease the association between the Cas9 domain and the sugar-phosphate backbone of a DNA. In some embodiments, a Cas9 domain comprises one or more mutations that decreases the association between the Cas9 domain and the sugar-phosphate backbone of DNA by at least 1%, at least 2%, at least 3%, at least 4%, at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least 70%.
In some embodiments, any of the Cas9 fusion proteins or complexes provided herein comprise one or more of a D10A, N497X, a R661X, a Q695X, and/or a Q926X mutation, or a corresponding mutation in any of the amino acid sequences provided herein, wherein X is any amino acid. In some embodiments, the high fidelity Cas9 enzyme is SpCas9(K855A), eSpCas9(1.1), SpCas9-HF1, or hyper accurate Cas9 variant (HypaCas9). In some embodiments, the modified Cas9 eSpCas9(1.1) contains alanine substitutions that weaken the interactions between the HNH/RuvC groove and the non-target DNA strand, preventing strand separation and cutting at off-target sites. Similarly, SpCas9-HF1 lowers off-target editing through alanine substitutions that disrupt Cas9's interactions with the DNA phosphate backbone. HypaCas9 contains mutations (SpCas9 N692A/M694A/Q695A/H698A) in the REC3 domain that increase Cas9 proofreading and target discrimination. All three high fidelity enzymes generate less off-target editing than wildtype Cas9.
Cas9 Domains with Reduced Exclusivity
Typically, Cas9 proteins, such as Cas9 from S. pyogenes (spCas9), require a “protospacer adjacent motif (PAM)” or PAM-like motif, which is a 2-6 base pair DNA sequence immediately following the DNA sequence targeted by the Cas9 nuclease in the CRISPR bacterial adaptive immune system. The presence of an NGG PAM sequence is required to bind a particular nucleic acid region, where the “N” in “NGG” is adenosine (A), thymidine (T), or cytosine (C), and the G is guanosine. This may limit the ability to edit desired bases within a genome. In some embodiments, the base editing fusion proteins or complexes provided herein may need to be placed at a precise location, for example a region comprising a target base that is upstream of the PAM. See e.g., Komor. A. C., et al., “Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage” Nature 533, 420-424 (2016), the entire contents of which are hereby incorporated by reference. Exemplary polypeptide sequences for spCas9 proteins capable of binding a PAM sequence are provided in the Sequence Listing as SEQ ID NOs: 197, 201, and 234-237. Accordingly, in some embodiments, any of the fusion proteins or complexes provided herein may contain a Cas9 domain that is capable of binding a nucleotide sequence that does not contain a canonical (e.g., NGG) PAM sequence. Cas9 domains that bind to non-canonical PAM sequences have been described in the art and would be apparent to the skilled artisan. For example. Cas9 domains that bind non-canonical PAM sequences have been described in Kleinstiver, B. P., et al., “Engineered CRISPR-Cas9 nucleases with altered PAM specificities” Nature 523, 481-485 (2015), and Kleinstiver, B. P., et al., “Broadening the targeting range of Staphylococcus aureus CRISPR-Cas9 by modifying PAM recognition” Nature Biotechnology 33, 1293-1298 (2015); the entire contents of each are hereby incorporated by reference.
In some embodiments, the nucleic acid programmable DNA binding protein (napDNAbp) is a single effector of a microbial CRISPR-Cas system. Single effectors of microbial CRISPR-Cas systems include, without limitation, Cas9, Cpf1, Cas12b/C2c1, and Cas12c/C2c3. Typically, microbial CRISPR-Cas systems are divided into Class 1 and Class 2 systems. Class I systems have multisubunit effector complexes, while Class 2 systems have a single protein effector. For example, Cas9 and Cpf1 are Class 2 effectors. In addition to Cas9 and Cpf1, three distinct Class 2 CRISPR-Cas systems (Cas12b/C2c1, and Cas12c/C2c3) have been described by Shmakov et al., “Discovery and Functional Characterization of Diverse Class 2 CRISPR Cas Systems”, Mol. Cell, 2015 Nov. 5; 60(3): 385-397, the entire contents of which is hereby incorporated by reference. Effectors of two of the systems, Cas12b/C2c1, and Cas12c/C2c3, contain RuvC-like endonuclease domains related to Cpf1. A third system contains an effector with two predicated HEPN RNase domains. Production of mature CRISPR RNA is tracrRNA-independent, unlike production of CRISPR RNA by Cas12b/C2c1, Cas12b/C2c1 depends on both CRISPR RNA and tracrRNA for DNA cleavage.
In some embodiments, the napDNAbp is a circular permutant (e.g., SEQ ID NO: 238).
In some embodiments, the polynucleotide programmable nucleotide binding domain comprises a nickase domain. Herein the term “nickase” refers to a polynucleotide programmable nucleotide binding domain comprising a nuclease domain that is capable of cleaving only one strand of the two strands in a duplexed nucleic acid molecule (e.g., DNA). In some embodiments, a nickase can be derived from a fully catalytically active (e.g., natural) form of a polynucleotide programmable nucleotide binding domain by introducing one or more mutations into the active polynucleotide programmable nucleotide binding domain. For example, where a polynucleotide programmable nucleotide binding domain comprises a nickase domain derived from Cas9, the Cas9-derived nickase domain can include a D10A mutation and a histidine at position 840. In such embodiments, the residue H840 retains catalytic activity and can thereby cleave a single strand of the nucleic acid duplex. In another example, a Cas9-derived nickase domain comprises an H840A mutation, while the amino acid residue at position 10 remains a D. In some embodiments, a nickase can be derived from a fully catalytically active (e.g., natural) form of a polynucleotide programmable nucleotide binding domain by removing all or a portion (e.g., a functional portion) of a nuclease domain that is not required for the nickase activity. For example, where a polynucleotide programmable nucleotide binding domain comprises a nickase domain derived from Cas9, the Cas9-derived nickase domain can comprise a deletion of all or a portion (e.g., a functional portion) of the RuvC domain or the HNH domain.
In some embodiments, wild-type Cas9 corresponds to, or comprises the following amino acid sequence:
LLFDSGETAEATRLKRTARRRYTRRKNRICYLQEIFSNEMAKVDDSFFHR
MGRHKPENIVIEMARENQTTQKGQKNSRERMKRIEEGIKELGSQILKEHP
VENTQLQNEKLYLYYLQNGRDMYVDQELDINRLSDYDVDHIVPQSFLKDD
SIDNKVLTRSDKNRGKSDNVPSEEVVKKMKNYWRQLLNAKLITQRKFDNL
TKAERGGLSELDKAGFIKRQLVETRQITKHVAQILDSRMNTKYDENDKLI
REVKVITLKSKLVSDFRKDFQFYKVREINNYHHAHDAYLNAVVGTALIKK
YPKLESEFVYGDYKVYDVRKMIAKSEQEIGKATAKYFFYSNIMNFFKTEI
TLANGEIRKRPLIETNGETGEIVWDKGRDFATVRKVLSMPQVNIVKKTEV
QTGGFSKESILPKRNSDKLIARKKDWDPKKYGGFDSPTVAYSVLVVAKVE
In some embodiments, the strand of a nucleic acid duplex target polynucleotide sequence that is cleaved by a base editor comprising a nickase domain (e.g., Cas9-derived nickase domain, Cas12-derived nickase domain) is the strand that is not edited by the base editor (i.e., the strand that is cleaved by the base editor is opposite to a strand comprising a base to be edited). In other embodiments, a base editor comprising a nickase domain (e.g., Cas9-derived nickase domain, Cas12-derived nickase domain) can cleave the strand of a DNA molecule which is being targeted for editing. In such embodiments, the non-targeted strand is not cleaved.
In some embodiments, a Cas9 nuclease has an inactive (e.g., an inactivated) DNA cleavage domain, that is, the Cas9 is a nickase, referred to as an “nCas9” protein (for “nickase” Cas9: SEQ ID NO: 201). The Cas9 nickase may be a Cas9 protein that is capable of cleaving only one strand of a duplexed nucleic acid molecule (e.g., a duplexed DNA molecule). In some embodiments the Cas9 nickase cleaves the target strand of a duplexed nucleic acid molecule, meaning that the Cas9 nickase cleaves the strand that is base paired to (complementary to) a gRNA (e.g., an sgRNA) that is bound to the Cas9. In some embodiments, a Cas9 nickase comprises a D10A mutation and has a histidine at position 840. In some embodiments the Cas9 nickase cleaves the non-target, non-base-edited strand of a duplexed nucleic acid molecule, meaning that the Cas9 nickase cleaves the strand that is not base paired to a gRNA (e.g., an sgRNA) that is bound to the Cas9. In some embodiments, a Cas9 nickase comprises an H840A mutation and has an aspartic acid residue at position 10, or a corresponding mutation. In some embodiments the Cas9 nickase comprises an amino acid sequence that is at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to any one of the Cas9 nickases provided herein. Additional suitable Cas9 nickases will be apparent to those of skill in the art based on this disclosure and knowledge in the field, and are within the scope of this disclosure.
Also provided herein are base editors comprising a polynucleotide programmable nucleotide binding domain which is catalytically dead (i.e., incapable of cleaving a target polynucleotide sequence). Herein the terms “catalytically dead” and “nuclease dead” are used interchangeably to refer to a polynucleotide programmable nucleotide binding domain which has one or more mutations and/or deletions resulting in its inability to cleave a strand of a nucleic acid. In some embodiments, a catalytically dead polynucleotide programmable nucleotide binding domain base editor can lack nuclease activity as a result of specific point mutations in one or more nuclease domains. For example, in the case of a base editor comprising a Cas9 domain, the Cas9 can comprise both a D10A mutation and an H840A mutation. Such mutations inactivate both nuclease domains, thereby resulting in the loss of nuclease activity. In other embodiments, a catalytically dead polynucleotide programmable nucleotide binding domain comprises one or more deletions of all or a portion (e.g., a functional portion) of a catalytic domain (e.g., RuvC1 and/or HNH domains). In further embodiments, a catalytically dead polynucleotide programmable nucleotide binding domain comprises a point mutation (e.g., D10A or H840A) as well as a deletion of all or a portion (e.g., a functional portion) of a nuclease domain. dCas9 domains are known in the art and described, for example, in Qi et al., “Repurposing CRISPR as an RNA-guided platform for sequence-specific control of gene expression.” Cell. 2013: 152(5):1173-83, the entire contents of which are incorporated herein by reference.
Additional suitable nuclease-inactive dCas9 domains will be apparent to those of skill in the art based on this disclosure and knowledge in the field, and are within the scope of this disclosure. Such additional exemplary suitable nuclease-inactive Cas9 domains include, but are not limited to, D10A/H840A, D10A/D839A/H840A, and D10A/D839A/H840A/N863A mutant domains (See, e.g., Prashant et al., CAS9 transcriptional activators for target specificity screening and paired nickases for cooperative genome engineering. Nature Biotechnology. 2013; 31(9): 833-838, the entire contents of which are incorporated herein by reference).
In some embodiments, dCas9 corresponds to, or comprises in part or in whole, a Cas9 amino acid sequence having one or more mutations that inactivate the Cas9 nuclease activity. In some embodiments, the nuclease-inactive dCas9 domain comprises a DIOX mutation and a H840X mutation of the amino acid sequence set forth herein, or a corresponding mutation in any of the amino acid sequences provided herein, wherein X is any amino acid change. In some embodiments, the nuclease-inactive dCas9 domain comprises a D10A mutation and a H840A mutation of the amino acid sequence set forth herein, or a corresponding mutation in any of the amino acid sequences provided herein. In some embodiments, a nuclease-inactive Cas9 domain comprises the amino acid sequence set forth in Cloning vector pPlatTET-gRNA2 (Accession No. BAV54124).
Fusion Proteins or Complexes with Internal Insertions
Provided herein are fusion proteins or complexes comprising a heterologous polypeptide fused to a nucleic acid programmable nucleic acid binding protein, for example, a napDNAbp. A heterologous polypeptide can be a polypeptide that is not found in the native or wild-type napDNAbp polypeptide sequence. The heterologous polypeptide can be fused to the napDNAbp at a C-terminal end of the napDNAbp, an N-terminal end of the napDNAbp, or inserted at an internal location of the napDNAbp. In some embodiments, the heterologous polypeptide is a deaminase (e.g., cytidine or adenosine deaminase) or a functional fragment thereof. For example, a fusion protein can comprise a deaminase flanked by an N-terminal fragment and a C-terminal fragment of a Cas9 or Cas12 (e.g., Cas12b/C2c1), polypeptide. In some embodiments, the cytidine deaminase is an APOBEC deaminase (e.g., APOBEC1). In some embodiments, the adenosine deaminase is a TadA (e.g., TadA*7.10 or TadA*8). In some embodiments, the TadA is a TadA*8 or a TadA*9. TadA sequences (e.g., TadA7.10 or TadA*8) as described herein are suitable deaminases for the above-described fusion proteins or complexes.
The deaminase can be a circular permutant deaminase. In some embodiments, the deaminase is a circular permutant TadA, circularly permutated at amino acid residue 116, 136, or 65 as numbered in a TadA reference sequence.
The fusion protein or complexes can comprise more than one deaminase. The fusion protein or complex can comprise, for example, 1, 2, 3, 4, 5 or more deaminases. In some embodiments, the fusion protein or complex comprises one or two deaminase. The two or more deaminases in a fusion protein or complex can be an adenosine deaminase, a cytidine deaminase, or a combination thereof. The two or more deaminases can be homodimers or heterodimers. The two or more deaminases can be inserted in tandem in the napDNAbp. In some embodiments, the two or more deaminases may not be in tandem in the napDNAbp.
In some embodiments, the napDNAbp in the fusion protein or complex is a Cas9 polypeptide or a fragment thereof. The Cas9 polypeptide can be a variant Cas9 polypeptide. The Cas9 polypeptide can be a circularly permuted Cas9 protein.
The heterologous polypeptide (e.g., deaminase) can be inserted in the napDNAbp (e.g., Cas9 or Cas12 (e.g., Cas12b/C2c1)) at a suitable location, for example, such that the napDNAbp retains its ability to bind the target polynucleotide and a guide nucleic acid. A deaminase (e.g., adenosine deaminase, cytidine deaminase, or adenosine deaminase and cytidine deaminase (dual deaminase)) can be inserted into a napDNAbp without compromising function of the deaminase (e.g., base editing activity) or the napDNAbp (e.g., ability to bind to target nucleic acid and guide nucleic acid). A deaminase (e.g., adenosine deaminase, cytidine deaminase, or adenosine deaminase and cytidine deaminase) can be inserted in the napDNAbp at, for example, a disordered region or a region comprising a high temperature factor or B-factor as shown by crystallographic studies. Regions of a protein that are less ordered, disordered, or unstructured, for example solvent exposed regions and loops, can be used for insertion without compromising structure or function. A deaminase (e.g., adenosine deaminase, cytidine deaminase, or adenosine deaminase and cytidine deaminase) can be inserted in the napDNAbp in a flexible loop region or a solvent-exposed region. In some embodiments, the deaminase (e.g., adenosine deaminase, cytidine deaminase, or adenosine deaminase and cytidine deaminase) is inserted in a flexible loop of the Cas9 or the Cas12b/C2c1 polypeptide.
In some embodiments, the deaminase (e.g., adenosine deaminase, cytidine deaminase, or adenosine deaminase and cytidine deaminase) is inserted in regions of the Cas9 polypeptide comprising higher than average B-factors (e.g., higher B factors compared to the total protein or the protein domain comprising the disordered region). Cas9 polypeptide positions comprising a higher than average B-factor can include, for example, residues 768, 792, 1052, 1015, 1022, 1026, 1029, 1067, 1040, 1054, 1068, 1246, 1247, and 1248 as numbered in the above Cas9 reference sequence. Cas9 polypeptide regions comprising a higher than average B-factor can include, for example, residues 792-872, 792-906, and 2-791 as numbered in the above Cas9 reference sequence.
In some embodiments, a heterologous polypeptide (e.g., deaminase) is inserted in a flexible loop of a Cas9 polypeptide. The flexible loop portions can be selected from the group consisting of 530-537, 569-570, 686-691, 943-947, 1002-1025, 1052-1077, 1232-1247, or 1298-1300 as numbered in the above Cas9 reference sequence, or a corresponding amino acid residue in another Cas9 polypeptide. The flexible loop portions can be selected from the group consisting of: 1-529, 538-568, 580-685, 692-942, 948-1001, 1026-1051, 1078-1231, or 1248-1297 as numbered in the above Cas9 reference sequence, or a corresponding amino acid residue in another Cas9 polypeptide.
A heterologous polypeptide (e.g., adenine deaminase) can be inserted into a Cas9 polypeptide region corresponding to amino acid residues: 1017-1069, 1242-1247, 1052-1056, 1060-1077, 1002-1003, 943-947, 530-537, 568-579, 686-691, 1242-1247, 1298-1300, 1066-1077, 1052-1056, or 1060-1077 as numbered in the above Cas9 reference sequence, or a corresponding amino acid residue in another Cas9 polypeptide.
A heterologous polypeptide (e.g., adenine deaminase) can be inserted in place of a deleted region of a Cas9 polypeptide. The deleted region can correspond to an N-terminal or C-terminal portion of the Cas9 polypeptide. Exemplary internal fusions base editors are provided in Table 3A below:
A heterologous polypeptide (e.g., deaminase) can be inserted within a structural or functional domain of a Cas9 polypeptide. A heterologous polypeptide (e.g., deaminase) can be inserted between two structural or functional domains of a Cas9 polypeptide. A heterologous polypeptide (e.g., deaminase) can be inserted in place of a structural or functional domain of a Cas9 polypeptide, for example, after deleting the domain from the Cas9 polypeptide. The structural or functional domains of a Cas9 polypeptide can include, for example, RuvC I, RuvC II, RuvC III, Rec1, Rec2, PI, or HNH.
The fusion protein or complex can comprise more than one heterologous polypeptide. For example, the fusion protein or complex can additionally comprise one or more UGI domains and/or one or more nuclear localization signals. The two or more heterologous domains can be inserted in tandem. The two or more heterologous domains can be inserted at locations such that they are not in tandem in the NapDNAbp.
A fusion protein can comprise a linker between the deaminase and the napDNAbp polypeptide. The linker can be a peptide or a non-peptide linker. For example, the linker can be an XTEN, (GGGS)n (SEQ ID NO: 415), (GGGGS)n (SEQ ID NO: 416), (G)n(SEQ ID NO: 418), (EAAAK)n (SEQ ID NO: 417), (GGS)n(SEQ ID NO: 419), SGSETPGTSESATPES (SEQ ID NO: 249). In some embodiments, the fusion protein comprises a linker between the N-terminal Cas9 fragment and the deaminase. In some embodiments, the fusion protein comprises a linker between the C-terminal Cas9 fragment and the deaminase. In some embodiments, the N-terminal and C-terminal fragments of napDNAbp are connected to the deaminase with a linker. In some embodiments, the N-terminal and C-terminal fragments are joined to the deaminase domain without a linker. In some embodiments, the fusion protein comprises a linker between the N-terminal Cas9 fragment and the deaminase, but does not comprise a linker between the C-terminal Cas9 fragment and the deaminase. In some embodiments, the fusion protein comprises a linker between the C-terminal Cas9 fragment and the deaminase, but does not comprise a linker between the N-terminal Cas9 fragment and the deaminase.
In some embodiments, the napDNAbp in the fusion protein or complex is a Cas12 polypeptide, e.g., Cas12b/C2c1, or a functional fragment thereof capable of associating with a nucleic acid (e.g., a gRNA) that guides the Cas12 to a specific nucleic acid sequence. The Cas12 polypeptide can be a variant Cas12 polypeptide. In other embodiments, the N- or C-terminal fragments of the Cas12 polypeptide comprise a nucleic acid programmable DNA binding domain or a RuvC domain. In other embodiments, the fusion protein contains a linker between the Cas12 polypeptide and the catalytic domain. In other embodiments, the amino acid sequence of the linker is GGSGGS (SEQ ID NO: 250) or GSSGSETPGTSESATPESSG (SEQ ID NO: 251). In other embodiments, the linker is a rigid linker. In other embodiments of the above aspects, the linker is encoded by GGAGGCTCTGGAGGAAGC (SEQ ID NO: 252) or GGCTCTTCTGGATCTGAAACACCTGGCACAAGCGAGAGCGCCACCCCTGAGAGCTCTGGC (SEQ ID NO: 253).
In other embodiments, the fusion protein or complex contains a nuclear localization signal (e.g., a bipartite nuclear localization signal). In other embodiments, the amino acid sequence of the nuclear localization signal is MAPKKKRKVGIHGVPAA (SEQ ID NO: 261). In other embodiments of the above aspects, the nuclear localization signal is encoded by the following sequence:
ATGGCCCCAAAGAAGAAGCGGAAGGTCGGTATCCACGGAGTCCCAGCAGCC (SEQ ID NO: 262). In other embodiments, the Cas12b polypeptide contains a mutation that silences the catalytic activity of a RuvC domain. In other embodiments, the Cas12b polypeptide contains D574A, D829A and/or D952A mutations. In other embodiments, the fusion protein or complex further contains a tag (e.g., an influenza hemagglutinin tag).
In some embodiments, the fusion protein or complex comprises a napDNAbp domain (e.g., Cas12-derived domain) with an internally fused nucleobase editing domain (e.g., all or a portion (e.g., a functional portion) of a deaminase domain, e.g., an adenosine deaminase domain). In some embodiments, the napDNAbp is a Cas12b. In some embodiments, the base editor comprises a BhCas12b domain with an internally fused TadA*8 domain inserted at the loci provided in Table 3B below.
In some embodiments, the base editing system described herein is an ABE with TadA inserted into a Cas9. Polypeptide sequences of relevant ABEs with TadA inserted into a Cas9 are provided in the attached Sequence Listing as SEQ ID NOs: 263-308.
Exemplary, yet nonlimiting, fusion proteins are described in International PCT Application Nos. PCT/US2020/016285 and U.S. Provisional Application Nos. 62/852,228 and 62/852,224, the contents of which are incorporated by reference herein in their entireties.
In some embodiments, a base editor described herein comprises an adenosine deaminase domain. Such an adenosine deaminase domain of a base editor can facilitate the editing of an adenine (A) nucleobase to a guanine (G) nucleobase by deaminating the A to form inosine (1), which exhibits base pairing properties of G. Adenosine deaminase is capable of deaminating (i.e., removing an amine group) adenine of a deoxyadenosine residue in deoxyribonucleic acid (DNA). In some embodiments, an A-to-G base editor further comprises an inhibitor of inosine base excision repair, for example, a uracil glycosylase inhibitor (UGI) domain or a catalytically inactive inosine specific nuclease. Without wishing to be bound by any particular theory, the UGI domain or catalytically inactive inosine specific nuclease can inhibit or prevent base excision repair of a deaminated adenosine residue (e.g., inosine), which can improve the activity or efficiency of the base editor.
A base editor comprising an adenosine deaminase can act on any polynucleotide, including DNA, RNA and DNA-RNA hybrids. In an embodiment an adenosine deaminase domain of a base editor comprises all or a portion (e.g., a functional portion) of an ADAT comprising one or more mutations which permit the ADAT to deaminate a target A in DNA. For example, the base editor can comprise all or a portion (e.g., a functional portion) of an ADAT from Escherichia coli (EcTadA) comprising one or more of the following mutations: D108N, A106V, D147Y, E155V, L84F, H123Y, I156F, or a corresponding mutation in another adenosine deaminase. Exemplary ADAT homolog polypeptide sequences are provided in the Sequence Listing as SEQ ID NOs: 1 and 309-315.
The adenosine deaminase can be derived from any suitable organism (e.g., E. coli). In some embodiments, the adenosine deaminase is from Escherichia coli, Staphylococcus aureus. Salmonella typhi, Shewanella putrefaciens, Haemophilus influenzae, Caulobacter crescentus, or Bacillus subtilis. In some embodiments, the adenine deaminase is a naturally-occurring adenosine deaminase that includes one or more mutations corresponding to any of the mutations provided herein (e.g., mutations in ecTadA). The corresponding residue in any homologous protein can be identified by e.g., sequence alignment and determination of homologous residues. The mutations in any naturally-occurring adenosine deaminase (e.g., having homology to ecTadA) that correspond to any of the mutations described herein (e.g., any of the mutations identified in ecTadA) can be generated accordingly.
In some embodiments, the adenosine deaminase comprises an amino acid sequence that is at least 60%, at least 65%, at least 70/o, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to any one of the amino acid sequences set forth in any of the adenosine deaminases provided herein. It should be appreciated that adenosine deaminases provided herein may include one or more mutations (e.g., any of the mutations provided herein). The disclosure provides any deaminase domains with a certain percent identify plus any of the mutations or combinations thereof described herein. In some embodiments, the adenosine deaminase comprises an amino acid sequence that has 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or more mutations compared to a reference sequence, or any of the adenosine deaminases provided herein.
It should be appreciated that any of the mutations provided herein (e.g., based on a TadA reference sequence, such as TadA*7.10 (SEQ ID NO: 1)) can be introduced into other adenosine deaminases, such as E. coli TadA (ecTadA), S, aureus TadA (saTadA), or other adenosine deaminases (e.g., bacterial adenosine deaminases). In some embodiments, the TadA reference sequence is TadA*7.10 (SEQ ID NO: 1). It would be apparent to the skilled artisan that additional deaminases may similarly be aligned to identify homologous amino acid residues that can be mutated as provided herein. Thus, any of the mutations identified in a TadA reference sequence can be made in other adenosine deaminases (e.g., ecTada) that have homologous amino acid residues. It should also be appreciated that any of the mutations provided herein can be made individually or in any combination in a TadA reference sequence or another adenosine deaminase.
In some embodiments, the adenosine deaminase comprises an A106X, E155X, or D147X, mutation in a TadA reference sequence, or a corresponding mutation in another adenosine deaminase (e.g., ecTadA), where X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises an E155D, E155G, or E155V mutation. In some embodiments, the adenosine deaminase comprises a D147Y.
It should also be appreciated that any of the mutations provided herein may be made individually or in any combination in ecTadA or another adenosine deaminase. For example, an adenosine deaminase may contain a D108N, a A106V, a E155V, and/or a D147Y mutation in a TadA reference sequence, or a corresponding mutation in another adenosine deaminase (e.g., ecTadA).
In some embodiments, the adenosine deaminase comprises one or more of a H8X, T17X, L18X, W23X, L34X, W45X, R51X, A56X, E59X, E85X, M94X, 195X, V102X, F104X, A106X, R107X, D108X, K110X, M 118X, N127X, A138X, F149X, M151X, R153X. Q154X, I156X, and/or K157X mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase, where the presence of X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of H8Y, T17S, L18E, W23L, W23R, L34S, W45L, R51H, A56E, or A56S, E59G, E85K, or E85G, M94L, 195L, V102A, F104L, A106V, R107C, or R107H, or R107P, D108G, or D108N, or D108V, or D108A, or D108Y, K110I, M118K, N127S. A138V, F149Y, M151V, R153C, Q154L, 1156D, and/or K157R mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase.
In some embodiments, the adenosine deaminase comprises one or more of H8X, R26X, M61X, L68X, M70X, A106X, D108X, A109X, N127X. D147X, R152X. Q154X, E155X.
K161X, Q163X, and/or T166X mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase, where X indicates the presence of any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of H8Y, R26W, M611, L68Q, M70V, A106T, D108N, A109T, N127S, D147Y, R152C, R162P, R162H, Q154H or Q154R, E155G or E155V or E155D, K161Q, Q163H, and/or T166P mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase.
In some embodiments, the adenosine deaminase comprises one, two, three, four, five, six, or seven mutations selected from the group consisting of H8X, R126X, L68X, D108X, N127X, D147X, and E155X in a TadA reference sequence, or a corresponding mutation or mutations in another adenosine deaminase, where X indicates the presence of any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase.
In some embodiments, the adenosine deaminase comprises one or more of S2X, H8X, I49X, L84X, H123X, N127X, I156X, and/or K160X mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase, where the presence of X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of S2A, H8Y, 149F, L84F, H123Y, N127S, I156F, and/or K160S mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase (e.g., ecTadA).
In some embodiments, the adenosine deaminase comprises one, two, three, four, five, six, or seven mutations selected from the group consisting of L84X, A106X, D108X, H123X, D147X, E155X, and I156X in a TadA reference sequence, or a corresponding mutation or mutations in another adenosine deaminase, where X indicates the presence of any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one, two, three, four, five, or six mutations selected from the group consisting of S2X I49X. A106X, D108X, D147X, and E155X in a TadA reference sequence, or a corresponding mutation or mutations in another adenosine deaminase, where X indicates the presence of any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one, two, three, four, or five mutations selected from the group consisting of H8X, A106X, D108X, N127X, and K160X in a TadA reference sequence, or a corresponding mutation or mutations in another adenosine deaminase, where X indicates the presence of any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase.
In some embodiments, the adenosine deaminase comprises one, two, three, four, or five mutations selected from the group consisting of H8Y, A106T, D108N, N127S, and K160S in a TadA reference sequence, or a corresponding mutation or mutations in another adenosine deaminase.
In some embodiments, the adenosine deaminase comprises one or more of a E25X, R26X, R107X, A142X, and/or A143X mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase, where the presence of X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of E25M, E25D, E25A, E25R, E25V, E25S. E25Y, R26G, R26N, R26Q, R26C, R26L, R26K, R107P, R107K, R107A, R107N, R107W, R107H, R107S, A142N, A142D, A142G. A143D, A143G, A143E, A143L, A143W, A143M, A143S, A143Q, and/or A143R mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of the mutations described herein corresponding to TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase.
In some embodiments, the adenosine deaminase comprises one or more of a H36X, N37X, P48X, I49X, R51X, M70X, N72X, D77X, E134X, S146X, Q154X, K157X, and/or K161X mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase, where the presence of X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of H36L, N37T, N37S, P48T, P48L, I49V, R51H, R51L, M70L, N72S, D77G, E134G, S146R, S146C, Q154H, K157N, and/or K161T mutation in a TadA reference sequence, or one or more corresponding mutations in another adenosine deaminase (e.g., ecTadA).
In some embodiments, the adenosine deaminase comprises the following combination of mutations relative to TadA reference sequence, where each mutation of a combination is separated by a “_” and each combination of mutations is between parentheses:
In some embodiments, TadA*7.10 comprises an alteration at amino acid 82 and/or 166. In particular embodiments, TadA*7.10 comprises one or more of the following alterations. Y147T, Y147R, Q154S, Y123H, V82S, T166R, and/or Q154R.
In some embodiments, a variant of TadA*7.10 comprises one or more of alterations selected from the group of L36H, I76Y, V82G, Y147T, Y147D, F149Y, Q154S, N157K, and/or D167N.
In embodiments, a variant of TadA*7.10 comprises one or more alterations selected from any of those alterations provided herein.
In particular embodiments, an adenosine deaminase heterodimer comprises a TadA*8 domain and an adenosine deaminase domain selected from Staphylococcus aureus (S, aureus) TadA, Bacillus subtilis (B. subtilis) TadA, Salmonella typhimurium (S. typhimurium) TadA, Shewanella putrefaciens (S. putrefaciens) TadA, Haemophilus influenzae F3031 (H. influenzae) TadA, Caulobacter crescentus (C. crescentus) TadA, Geobacter sulfurreducens (G. sulfurreducens) TadA, or TadA*7.10.
In some embodiments, an adenosine deaminase is a TadA*8. In one embodiment, an adenosine deaminase is a TadA*8 that comprises or consists essentially of the following sequence or a fragment thereof having adenosine deaminase activity:
In some embodiments the TadA*8 is TadA*8.1, TadA*8.2, TadA*8.3, TadA*8.4, TadA*8.5, TadA*8.6, TadA*8.7, TadA*8.8, TadA*8.9, TadA*8.10, TadA*8.11, TadA*8.12, TadA*8.13, TadA*8.14, TadA*8.15, TadA*8.16, TadA*8.17, TadA*8.18, TadA*8.19, TadA*8.20, TadA*8.21, TadA*8.22, TadA*8.23, or TadA*8.24.
In some embodiments, the TadA*8 is a variant as shown in Table 4. Table 4 shows certain amino acid position numbers in the TadA amino acid sequence and the amino acids present in those positions in the TadA-7.10 adenosine deaminase. Table 4 also shows amino acid changes in TadA variants relative to TadA-7.10 following phage-assisted non-continuous evolution (PANCE) and phage-assisted continuous evolution (PACE), as described in M. Richter et al., 2020, Nature Biotechnology, doi.org/10.1038/s41587-020-0453-z, the entire contents of which are incorporated by reference herein. In some embodiments, the TadA*8 is TadA*8a, TadA*8b, TadA*8c, TadA*8d, or TadA*8e. In some embodiments, the TadA*8 is TadA*8e.
In some embodiments, the TadA variant is a variant as shown in Table 5. Table 5 shows certain amino acid position numbers in the TadA amino acid sequence and the amino acids present in those positions in the TadA*7.10 adenosine deaminase. In some embodiments, the TadA variant is MSP605, MSP68, MSP823, MSP824, MSP825, MSP827, MSP828, or MSP829. In some embodiments, the TadA variant is MSP828. In some embodiments, the TadA variant is MSP829.
In particular embodiments, a TadA*8 comprises one or more mutations at any of the following positions shown in bold. In other embodiments, a TadA*8 comprises one or more mutations at any of the positions shown with underlining:
In particular embodiments, the fusion proteins or complexes comprise a single (e.g., provided as a monomer) TadA*8. In some embodiments, the TadA*8 is linked to a Cas9 nickase. In some embodiments, the fusion proteins or complexes of the invention comprise as a heterodimer of a wild-type TadA (TadA(wt)) linked to a TadA*8. In other embodiments, the fusion proteins or complexes of the invention comprise as a heterodimer of a TadA*7.10 linked to a TadA*8. In some embodiments, the base editor is ABE8 comprising a TadA*8 variant monomer. In some embodiments, the base editor is ABE8 comprising a heterodimer of a TadA*8 and a TadA(wt). In some embodiments, the base editor is ABE8 comprising a heterodimer of a TadA*8 and TadA*7.10. In some embodiments, the base editor is ABE8 comprising a heterodimer of a TadA*8. In some embodiments, the TadA*8 is selected from Table 4, 10, or 11. In some embodiments, the ABE8 is selected from Table 10, 11, or 13.
In some embodiments, the adenosine deaminase is a TadA*9 variant. In some embodiments, the adenosine deaminase is a TadA*9 variant selected from the variants described below and with reference to the following sequence (termed TadA*7.10):
In some embodiments, an adenosine deaminase comprises one or more of the following alterations; R21N, R23H, E25F, N38G, L51W, P54C, M70V, Q71M, N72K, Y73S, V82T, M94V, P124W, T133K, D139L, D139M, C146R, and A158K. The one or more alternations are shown in the sequence above in underlining and bold font.
In some embodiments, the adenosine deaminase is expressed as a monomer. In other embodiments, the adenosine deaminase is expressed as a heterodimer. In some embodiments, the deaminase or other polypeptide sequence lacks a methionine, for example when included as a component of a fusion protein. This can alter the numbering of positions. However, the skilled person will understand that such corresponding mutations refer to the same mutation, e.g., Y73S and Y72S and D139M and D138M.
In some embodiments, the TadA*9 variant comprises the alterations described in Table 14 as described herein. In some embodiments, the TadA*9 variant is a monomer. In some embodiments, the TadA*9 variant is a heterodimer with a wild-type TadA adenosine deaminase. In some embodiments, the TadA*9 variant is a heterodimer with another TadA variant (e.g., TadA*8, TadA*9). Additional details of TadA*9 adenosine deaminases are described in International PCT Application No. PCT/US2020/049975, which is incorporated herein by reference for its entirety.
In some embodiments, the adenosine deaminase comprises one or more of a R46X, E59X, E70X, V106X, A106X, N108X, and/or a D108X mutation in a TadA reference sequence (e.g., ecTadA or TadA*7.10), or one or more corresponding mutations in another adenosine deaminase, where the presence of X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase. In some embodiments, the adenosine deaminase comprises one or more of an R46W, R46F, R46Q, R46M, R47Q, R47F, R47W, R47M, E59Q, E59W, E59A, 59A, E70A, V106Q, V106F, V106W, V106M, A106Q, A106F, A106W, A106M, A106V, N108Q, N108F, N108W, N108M, N108K, D108N, D108K, D108F, D108M, D108Q, and/or D108W mutation in a TadA reference sequence (e.g., ecTadA or TadA*7.10), or one or more corresponding mutations in another adenosine deaminase. In some cases, the adenosine deaminase comprises a combination of mutations in a TadA reference sequence (e.g., ecTadA or TadA*7.10), or corresponding mutations in another adenosine deaminase, selected from one or more of the following combinations of mutations, where X indicates any amino acid other than the corresponding amino acid in the wild-type adenosine deaminase: R47X, V106X, and/or N108X: N46X, E59X, A106X, and/or D108X: V106W, N108W, and/or a mutation at position R47 selected from Q, F, W, and M; D108N, A106V, and/or R47Q: D108W, A106W, and/or R47Q; and D108X, A106X, and/or R47X. In some embodiments, the adenosine deaminase comprises a mutation at position 59 in a TadA reference sequence (e.g., ecTadA or TadA*7.10), or one or more corresponding mutations in another adenosine deaminase, where the mutation is to any amino acid other than E. In some embodiments, the adenosine deaminase comprises a mutation at position 108 in a TadA reference sequence (e.g., ecTadA or TadA*7.10), or one or more corresponding mutations in another adenosine deaminase, where the mutation is to any amino acid other than N, A, G. V, Y, L, or I. Additional mutations are described in U.S. Patent Application Publication No. 2022/0307003 A1, the disclosure of which is incorporated herein by reference in its entirety for all purposes.
Any of the mutations provided herein and any additional mutations (e.g., based on the ecTadA amino acid sequence) can be introduced into any other adenosine deaminases. Any of the mutations provided herein can be made individually or in any combination in a TadA reference sequence or another adenosine deaminase (e.g., ecTadA).
Details of A to G nucleobase editing proteins are described in International PCT Application No. PCT/US2017/045381 (WO2018/027078) and Gaudelli, N. M., et al., “Programmable base editing of A·T to G·C in genomic DNA without DNA cleavage” Nature, 551, 464-471 (2017), the entire contents of which are hereby incorporated by reference.
In some embodiments, a base editor disclosed herein comprises a fusion protein or complex comprising cytidine deaminase capable of deaminating a target cytidine (C) base of a polynucleotide to produce uridine (U), which has the base pairing properties of thymine. In some embodiments, for example where the polynucleotide is double-stranded (e.g., DNA), the uridine base can then be substituted with a thymidine base (e.g., by cellular repair machinery) to give rise to a C:G to a T:A transition. In other embodiments, deamination of a C to U in a nucleic acid by a base editor cannot be accompanied by substitution of the U to a T.
The deamination of a target C in a polynucleotide to give rise to a U is a non-limiting example of a type of base editing that can be executed by a base editor described herein. In another example, a base editor comprising a cytidine deaminase domain can mediate conversion of a cytosine (C) base to a guanine (G) base. For example, a U of a polynucleotide produced by deamination of a cytidine by a cytidine deaminase domain of a base editor can be excised from the polynucleotide by a base excision repair mechanism (e.g., by a uracil DNA glycosylase (UDG) domain), producing an abasic site. The nucleobase opposite the abasic site can then be substituted (e.g., by base repair machinery) with another base, such as a C, by for example a translesion polymerase. Although it is typical for a nucleobase opposite an abasic site to be replaced with a C, other substitutions (e.g., A, G or T) can also occur.
Accordingly, in some embodiments a base editor described herein comprises a deamination domain (e.g., cytidine deaminase domain) capable of deaminating a target C to a U in a polynucleotide. Further, as described below, the base editor can comprise additional domains which facilitate conversion of the U resulting from deamination to, in some embodiments, a T or a G. For example, a base editor comprising a cytidine deaminase domain can further comprise a uracil glycosylase inhibitor (UGI) domain to mediate substitution of a U by a T, completing a C-to-T base editing event. In another example, the base editor can comprise a uracil stabilizing protein as described herein. In another example, a base editor can incorporate a translesion polymerase to improve the efficiency of C-to-G base editing, since a translesion polymerase can facilitate incorporation of a C opposite an abasic site (i.e., resulting in incorporation of a G at the abasic site, completing the C-to-G base editing event).
A base editor comprising a cytidine deaminase as a domain can deaminate a target C in any polynucleotide, including DNA, RNA and DNA-RNA hybrids.
In some embodiments, a cytidine deaminase of a base editor comprises all or a portion (e.g., a functional portion) of an apolipoprotein B mRNA editing complex (APOBEC) family deaminase. APOBEC is a family of evolutionarily conserved cytidine deaminases. Members of this family are C-to-U editing enzymes. The N-terminal domain of APOBEC like proteins is the catalytic domain, while the C-terminal domain is a pseudocatalytic domain. More specifically, the catalytic domain is a zinc dependent cytidine deaminase domain and is important for cytidine deamination. APOBEC family members include APOBEC1, APOBEC2, APOBEC3A, APOBEC3B, APOBEC3C, APOBEC3D (“APOBEC3E” now refers to this), APOBEC3F, APOBEC3G, APOBEC3H, APOBEC4, and Activation-induced (cytidine) deaminase.
Other exemplary deaminases that can be fused to Cas9 according to aspects of this disclosure are provided below. In embodiments, the deaminases are activation-induced deaminases (AID). It should be understood that, in some embodiments, the active domain of the respective sequence can be used, e.g., the domain without a localizing signal (nuclear localization sequence, without nuclear export signal, cytoplasmic localizing signal).
Some aspects of the present disclosure are based on the recognition that modulating the deaminase domain catalytic activity of any of the fusion proteins or complexes described herein, for example by making point mutations in the deaminase domain, affect the processivity of the fusion proteins (e.g., base editors) or complexes. For example, mutations that reduce, but do not eliminate, the catalytic activity of a deaminase domain within a base editing fusion protein or complexes can make it less likely that the deaminase domain will catalyze the deamination of a residue adjacent to a target residue, thereby narrowing the deamination window. The ability to narrow the deamination window can prevent unwanted deamination of residues adjacent to specific target residues, which can decrease or prevent off-target effects.
For example, in some embodiments, an APOBEC deaminase incorporated into a base editor comprises one or more mutations selected from the group consisting of H121X, H122X, R126X, R126X, R118X, W90X, W90X, and R132X of rAPOBEC1, or one or more corresponding mutations in another APOBEC deaminase, wherein X is any amino acid. In some embodiments, an APOBEC deaminase incorporated into a base editor can comprise one or more mutations selected from the group consisting of H121R, H122R, R126A, R126E, R118A, W90A, W90Y, and R132E of rAPOBEC1, or one or more corresponding mutations in another APOBEC deaminase.
In some embodiments, an APOBEC deaminase incorporated into a base editor comprises one or more mutations selected from the group consisting of D316X, D317X, R320X, R320X, R313X, W285X, W285X, R326X of hAPOBEC3G, or one or more corresponding mutations in another APOBEC deaminase, wherein X is any amino acid. In some embodiments, any of the fusion proteins or complexes provided herein comprise an APOBEC deaminase comprising one or more mutations selected from the group consisting of D316R, D317R, R320A, R320E, R313A, W285A, W285Y, R326E of hAPOBEC3G, or one or more corresponding mutations in another APOBEC deaminase.
A number of modified cytidine deaminases are commercially available, including, but not limited to, SaBE3, SaKKH-BE3, VQR-BE3, EQR-BE3, VRER-BE3, YE1-BE3, EE-BE3, YE2-BE3, and YEE-BE3, which are available from Addgene (plasmids 85169, 85170, 85171, 85172, 85173, 85174, 85175, 85176, 85177). In some embodiments, a deaminase incorporated into a base editor comprises all or a portion (e.g., a functional portion) of an APOBEC1 deaminase.
In some embodiments, the fusion proteins or complexes of the invention comprise one or more cytidine deaminase domains. In some embodiments, the cytidine deaminases provided herein are capable of deaminating cytosine or 5-methylcytosine to uracil or thymine. In some embodiments, the cytidine deaminases provided herein are capable of deaminating cytosine in DNA. The cytidine deaminase may be derived from any suitable organism. In some embodiments, the cytidine deaminase is a naturally-occurring cytidine deaminase that includes one or more mutations corresponding to any of the mutations provided herein. One of skill in the art will be able to identify the corresponding residue in any homologous protein, e.g., by sequence alignment and determination of homologous residues. Accordingly, one of skill in the art would be able to generate mutations in any naturally-occurring cytidine deaminase that corresponds to any of the mutations described herein. In some embodiments, the cytidine deaminase is from a prokaryote. In some embodiments, the cytidine deaminase is from a bacterium. In some embodiments, the cytidine deaminase is from a mammal (e.g., human).
In some embodiments, the cytidine deaminase comprises an amino acid sequence that is at least 60%, at least 65%, at least 7(%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or at least 99.5% identical to any one of the cytidine deaminase amino acid sequences set forth herein. It should be appreciated that cytidine deaminases provided herein may include one or more mutations (e.g., any of the mutations provided herein). Some embodiments provide a polynucleotide molecule encoding the cytidine deaminase nucleobase editor polypeptide of any previous aspect or as delineated herein. In some embodiments, the polynucleotide is codon optimized.
In embodiments, a fusion protein of the invention comprises two or more nucleic acid editing domains.
Details of C to T nucleobase editing proteins are described in International PCT Application No. PCT/US2016/058344 (WO2017/070632) and Komor, A. C., et al., “Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage” Nature 533, 420-424 (2016), the entire contents of which are hereby incorporated by reference.
In some embodiments, a base editor described herein comprises an adenosine deaminase variant that has increased cytidine deaminase activity. Such base editors may be referred to as “cytidine adenosine base editors (CABEs)” or “cytosine base editors derived from TadA* (CBE-Ts),” and their corresponding deaminase domains may be referred to as “TadA* acting on DNA cytosine (TADC)” domains. In some instances, an adenosine deaminase variant has both adenine and cytosine deaminase activity (i.e., is a dual deaminase). In some embodiments, the adenosine deaminase variants deaminate adenine and cytosine in DNA. In some embodiments, the adenosine deaminase variants deaminate adenine and cytosine in single-stranded DNA. In some embodiments, the adenosine deaminase variants deaminate adenine and cytosine in RNA. In some embodiments, the adenosine deaminase variant predominantly deaminates cytosine in DNA and/or RNA (e.g., greater than 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 99% of all deaminations catalyzed by the adenosine deaminase variant, or the number of cytosine deaminations catalyzed by the variant is about or at least about 2-fold, 3-fold, 4-fold, 5-fold, 6-fold, 7-fold, 8-fold, 9-fold, 10-fold, 25-fold, 50-fold, 75-fold, 100-fold, 500-fold, or 1,000-fold greater than the number adenine deaminations catalyzed by the variant). In some embodiments, the adenosine deaminase variant has approximately equal cytosine and adenosine deaminase activity (e.g., the two activities are within about 10% or 20% of each other). In some embodiments, the adenosine deaminase variant has predominantly cytosine deaminase activity, and little, if any, adenosine deaminase activity. In some embodiments, the adenosine deaminase variant has cytosine deaminase activity, and no significant or no detectable adenosine deaminase activity. In some embodiments, the target polynucleotide is present in a cell in vitro or in vivo. In some embodiments, the cell is a bacteria, yeast, fungi, insect, plant, or mammalian cell.
In some embodiments, the CABE comprises a bacterial TadA deaminase variant (e.g., ecTadA). In some embodiments, the CABE comprises a truncated TadA deaminase variant. In some embodiments, the CABE comprises a fragment of a TadA deaminase variant. In some embodiments, the CABE comprises a TadA*8.20 variant.
In some embodiments, the adenosine deaminase variants of the invention comprise one or more alterations. In some embodiments, an adenosine deaminase variant of the invention is a TadA adenosine deaminase comprising one or more alterations that increase cytosine deaminase activity (e.g., at least about 10-fold, 20-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold or more increase) while maintaining adenosine deaminase activity (e.g., at least about 30%, 40%, 50% or more of the activity of a reference adenosine deaminase (e.g., TadA*8.20 or TadA*8.19)). In some instances, the adenosine deaminase variant comprises one or more alterations that increase cytosine deaminase activity (e.g., at least about 10-fold, 20-fold, 30-fold, 40-fold, 50-fold, 60-fold, 70-fold or more increase) relative to the activity of a reference adenosine deaminase and comprise undetectable adenosine deaminase activity or adenosine deaminase activity that is less than 30%, 20%, 10%, or 5% of that of a reference adenosine deaminase. In some embodiments, the reference adenosine deaminase is TadA*8.20 or TadA*8.19.
In some embodiments, the adenosine deaminase variant is an adenosine deaminase comprising the amino acid sequence of SEQ ID NO: 1 and one or more alterations that increase cytosine deaminase activity. In various embodiments, the one or more alterations of the invention do not include a R amino acid at position 48 of SEQ ID NO: 1, or a corresponding mutation in another adenosine deaminase.
In some embodiments, the adenosine deaminase variant is an adenosine deaminase comprising one or more alterations at an amino acid position selected from 2, 4, 6, 13, 27, 29, 100, 112, 114, 115, 162, and 165 of an amino acid sequence having at least about 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or greater identity to SEQ ID NO: 1, or a corresponding alteration in another deaminase. In some embodiments, the adenosine deaminase variant is an adenosine deaminase comprising two or more alterations at an amino acid position selected from the group consisting of 2, 4, 6, 8, 13, 17, 23, 27, 29, 30, 47, 48, 49, 67, 76, 77, 82, 84, 96, 100, 107, 112, 114, 115, 118, 119, 122, 127, 142, 143, 147, 149, 158, 159, 162 165, 166, and 167, of an amino acid sequence having at least about 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or greater identity to SEQ ID NO: 1, or a corresponding alteration in another deaminase. In some embodiments, the two or more alterations are at an amino acid position selected from the group consisting of S2X, V4X, F6X, H8X, R13X, T17X, R23X, E27X, P29X, V30X, R47X, A48X, I49X, G67X, Y76X, D77X, S82X, F84X, H96X, G100X, R107X, GI 12X, A114X, G115X, M118X, D119X, H122X, N127X, A142X, A143X, R147X, Y147X, F149X, A158X, Q159X, A162X, S165X, T166X, and D167X of an amino acid sequence having at least about 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or greater identity to SEQ ID NO: 1, or a corresponding alteration in another deaminase. In various embodiments, the alterations of the invention do not include a 48R mutation. In some embodiments, the adenosine deaminase variant is an adenosine deaminase comprising one or more alterations at an amino acid position selected from 2, 4, 6, 13, 27, 29, 100, 112, 114, 115, 162, and 165 of an amino acid sequence having at least about 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or greater identity to SEQ ID NO: 1, or a corresponding alteration in another deaminase.
In some embodiments, the adenosine deaminase variant is an adenosine deaminase comprising one or more alterations selected from the group consisting of S2H, V4K, V4S, V4T, V4Y, F6G, F6H, F6Y, H8Q, R13G, T17A, T17W, R23Q, E27C, E27G, E27H, E27K, E27Q, E27S, E27G, P29A, P29G, P29K, V30F, V301, R47G, R47S, A48G, 149K. 149M, 149N, 149Q, I49T, G67W, I76H, I76R, I76W, Y76H, Y76R, Y76W, F84A, F84M, H96N, G100A, G100K, T111H, G112H, A114C, G115M, M118L, H122G, H122R, H122T, N127I, N127K, N127P, A142E, R147H, A158V, Q159S, A162C, A162N, A162Q, and S165P of an amino acid sequence having at least about 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or greater identity to SEQ ID NO; 1, or a corresponding alteration in another deaminase.
In some embodiments, the adenosine deaminase variant is an adenosine deaminase comprising an amino acid alteration or combination of amino acid alterations selected from those listed in any of Tables 6 A-6F.
The residue identity of exemplary adenosine deaminase variants that are capable of deaminating adenine and/or cytidine in a target polynucleotide (e.g., DNA) is provided in Tables 6A-6F below. Further examples of adenosine deaminase variants include the following variants of 1.17 (see Table 6A): 1.17+E27H; 1.17+E27K; 1.17+E27S: 1.17+E27S+I49K; 1.17+E27G; 1.17+I49N, 1.17+E27G+I49N; and 1.17+E27Q. In some embodiments, any of the amino acid alterations provided herein are substituted with a conservative amino acid. Additional mutations known in the art can be further added to any of the adenosine deaminase variants provided herein.
In some embodiments, the base editor systems comprising a CABE provided herein have at least about a 30%, 40%, 50%, 60%, 70% or more C to T editing activity in a target polynucleotide (e.g., DNA). In some embodiments, a base editor system comprising a CABE as provided herein has an increased C to T base editing activity (e.g., increased at least about 30-fold, 40-fold, 50-fold, 60-fold, 70-fold or more) relative to a reference base editor system comprising a reference adenosine deaminase (e.g., TadA*8.20 or TadA*8.19).
A polynucleotide programmable nucleotide binding domain, when in conjunction with a bound guide polynucleotide (e.g., gRNA), can specifically bind to a target polynucleotide sequence (i.e., via complementary base pairing between bases of the bound guide nucleic acid and bases of the target polynucleotide sequence) and thereby localize the base editor to the target nucleic acid sequence desired to be edited. In some embodiments, the target polynucleotide sequence comprises single-stranded DNA or double-stranded DNA. In some embodiments, the target polynucleotide sequence comprises RNA. In some embodiments, the target polynucleotide sequence comprises a DNA-RNA hybrid.
In an embodiment, a guide polynucleotide described herein can be RNA or DNA. In one embodiment, the guide polynucleotide is a gRNA. An RNA/Cas complex can assist in “guiding” a Cas protein to a target DNA. Single guide RNAs (“sgRNA”, or simply “gRNA”) can be engineered so as to incorporate aspects of both the crRNA and tracrRNA into a single RNA species. See, e.g., Jinek M. et al., Science 337:816-821(2012), the entire contents of which is hereby incorporated by reference.
In some embodiments, the guide polynucleotide is at least one single guide RNA (“sgRNA” or “gRNA”). In some embodiments, a guide polynucleotide comprises two or more individual polynucleotides, which can interact with one another via for example complementary base pairing (e.g., a dual guide polynucleotide, dual gRNA). For example, a guide polynucleotide can comprise a CRISPR RNA (crRNA) and a trans-activating CRISPR RNA (tracrRNA) or can comprise one or more trans-activating CRISPR RNA (tracrRNA).
A guide polynucleotide may include natural or non-natural (or unnatural) nucleotides (e.g., peptide nucleic acid or nucleotide analogs). In some cases, the targeting region of a guide nucleic acid sequence (e.g., a spacer) can be at least 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 nucleotides in length.
In some embodiments, the base editor provided herein utilizes one or more guide polynucleotide (e.g., multiple gRNA). In some embodiments, a single guide polynucleotide is utilized for different base editors described herein. For example, a single guide polynucleotide can be utilized for a cytidine base editor and an adenosine base editor.
In some embodiments, the methods described herein can utilize an engineered Cas protein. A guide RNA (gRNA) is a short synthetic RNA composed of a scaffold sequence necessary for Cas-binding and a user-defined ˜20 nucleotide spacer that defines the genomic target to be modified. Exemplary gRNA scaffold sequences are provided in the sequence listing as SEQ ID NOs: 317-327 and 389. Thus, a skilled artisan can change the genomic target of the Cas protein specificity is partially determined by how specific the gRNA targeting sequence is for the genomic target compared to the rest of the genome.
In other embodiments, a guide polynucleotide comprises both the polynucleotide targeting portion of the nucleic acid (e.g., a spacer) and the scaffold portion of the nucleic acid in a single molecule (i.e., a single-molecule guide nucleic acid). For example, a single-molecule guide polynucleotide can be a single guide RNA (sgRNA or gRNA).
Typically, a guide polynucleotide (e.g., crRNA/trRNA complex or a gRNA) comprises a “polynucleotide-targeting segment” that includes a sequence capable of recognizing and binding to a target polynucleotide sequence, and a “protein-binding segment” that stabilizes the guide polynucleotide within a polynucleotide programmable nucleotide binding domain component of a base editor. In some embodiments, the polynucleotide targeting segment of the guide polynucleotide recognizes and binds to a DNA polynucleotide, thereby facilitating the editing of a base in DNA. In other cases, the polynucleotide targeting portion of the guide polynucleotide recognizes and binds to an RNA polynucleotide, thereby facilitating the editing of a base in RNA. In some embodiments, a protein-binding segment of a DNA-targeting RNA that comprises two separate molecules comprises (i) base pairs 40-75 of a first RNA molecule that is 100 base pairs in length; and (ii) base pairs 10-25 of a second RNA molecule that is 50 base pairs in length. The definition of “segment,” unless otherwise specifically defined in a particular context, is not limited to a specific number of total base pairs, is not limited to any particular number of base pairs from a given RNA molecule, is not limited to a particular number of separate molecules within a complex, and can include regions of RNA molecules that are of any total length and can include regions with complementarity to other molecules.
The guide polynucleotides can be synthesized chemically, synthesized enzymatically, or a combination thereof. For example, the gRNA can be synthesized using standard phosphoramidite-based solid-phase synthesis methods. Alternatively, the gRNA can be synthesized in vitro by operably linking DNA encoding the gRNA to a promoter control sequence that is recognized by a phage RNA polymerase. Examples of suitable phage promoter sequences include T7, T3, SP6 promoter sequences, or variations thereof. In embodiments in which the gRNA comprises two separate molecules (e.g., crRNA and tracrRNA), the crRNA can be chemically synthesized and the tracrRNA can be enzymatically synthesized.
A guide polynucleotide may be expressed, for example, by a DNA that encodes the gRNA, e.g., a DNA vector comprising a sequence encoding the gRNA. The gRNA may be encoded alone or together with an encoded base editor. Such DNA sequences may be introduced into an expression system, e.g., a cell, together or separately. For example, DNA sequences encoding a polynucleotide programmable nucleotide binding domain and a gRNA may be introduced into a cell, each DNA sequence can be part of a separate molecule (e.g., one vector containing the polynucleotide programmable nucleotide binding domain coding sequence and a second vector containing the gRNA coding sequence) or both can be part of a same molecule (e.g., one vector containing coding (and regulatory) sequence for both the polynucleotide programmable nucleotide binding domain and the gRNA). An RNA can be transcribed from a synthetic DNA molecule, e.g., a gBlocks® gene fragment. A gRNA molecule can be transcribed in vitro.
A gRNA or a guide polynucleotide can comprise three regions: a first region at the 5′ end that can be complementary to a target site in a chromosomal sequence, a second internal region that can form a stem loop structure, and a third 3′ region that does not form a secondary structure or bind a target site. A first region of each gRNA can also be different such that each gRNA guides a fusion protein or complex to a specific target site. Further, second and third regions of each gRNA can be identical in all gRNAs.
A first region of a gRNA or a guide polynucleotide can be complementary to sequence at a target site in a chromosomal sequence such that the first region of the gRNA can base pair with the target site. In some cases, a first region of a gRNA comprises from or from about 10 nucleotides to 25 nucleotides (i.e., from 10 nucleotides to nucleotides; or from about 10 nucleotides to about 25 nucleotides; or from 10 nucleotides to about 25 nucleotides; or from about 10 nucleotides to 25 nucleotides) or more. For example, a region of base pairing between a first region of a gRNA and a target site in a chromosomal sequence can be or can be about 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, or more nucleotides in length. Sometimes, a first region of a gRNA can be or can be about 19, 20, or 21 nucleotides in length.
A gRNA or a guide polynucleotide can also comprise a second region that forms a secondary structure. For example, a secondary structure formed by a gRNA can comprise a stem (or hairpin) and a loop. A length of a loop and a stem can vary. For example, a loop can range from or from about 3 to 10 nucleotides in length, and a stem can range from or from about 6 to base pairs in length. A stem can comprise one or more bulges of 1 to 10 or about 10 nucleotides. The overall length of a second region can range from or from about 16 to 60 nucleotides in length. For example, a loop can be or can be about 4 nucleotides in length and a stem can be or can be about 12 base pairs.
A gRNA or a guide polynucleotide can also comprise a third region at the 3′ end that can be essentially single-stranded. For example, a third region is sometimes not complementarity to any chromosomal sequence in a cell of interest and is sometimes not complementarity to the rest of a gRNA. Further, the length of a third region can vary. A third region can be more than or more than about 4 nucleotides in length. For example, the length of a third region can range from or from about 5 to 60 nucleotides in length.
A gRNA or a guide polynucleotide can target any exon or intron of a gene target. In some cases, a guide can target exon 1 or 2 of a gene, in other cases; a guide can target exon 3 or 4 of a gene. In some embodiments, a composition comprises multiple gRNAs that all target the same exon or multiple gRNAs that target different exons. An exon and/or an intron of a gene can be targeted.
A gRNA or a guide polynucleotide can target a nucleic acid sequence of about 20 nucleotides or less than about 20 nucleotides (e.g., at least about 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30 nucleotides), or anywhere between about 1-100 nucleotides (e.g., 5, 10, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 30, 40, 50, 60, 70, 80, 90, 100). A target nucleic acid sequence can be or can be about 20 bases immediately 5′ of the first nucleotide of the PAM. A gRNA can target a nucleic acid sequence. A target nucleic acid can be at least or at least about 1-10, 1-20, 1-30, 1-40, 1-50, 1-60, 1-70, 1-80, 1-90, or 1-100 nucleotides.
Methods for selecting, designing, and validating guide polynucleotides, e.g., gRNAs and targeting sequences are known to those skilled in the art. For example, to minimize the impact of potential substrate promiscuity of a deaminase domain in the nucleobase editor system (e.g., an AID domain), the number of residues that could unintentionally be targeted for deamination (e.g., off-target C residues that could potentially reside on single strand DNA within the target nucleic acid locus) may be minimized. In addition, software tools can be used to optimize the gRNAs corresponding to a target nucleic acid sequence, e.g., to minimize total off-target activity across the genome. For example, for each possible targeting domain choice using S. pyogenes Cas9, all off-target sequences (preceding selected PAMs, e.g., NAG or NGG) may be identified across the genome that contain up to certain number (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10) of mismatched base-pairs. First regions of gRNAs complementary to a target site can be identified, and all first regions (e.g., crRNAs) can be ranked according to its total predicted off-target score; the top-ranked targeting domains represent those that are likely to have the greatest on-target and the least off-target activity. Candidate targeting gRNAs can be functionally evaluated by using methods known in the art and/or as set forth herein.
A gRNA can then be introduced into a cell or embryo as an RNA molecule or a non-RNA nucleic acid molecule, e.g., DNA molecule. In one embodiment, a DNA encoding a gRNA is operably linked to promoter control sequence for expression of the gRNA in a cell or embryo of interest. A RNA coding sequence can be operably linked to a promoter sequence that is recognized by RNA polymerase III (Pol III). Plasmid vectors that can be used to express gRNA include, but are not limited to, px330 vectors and px333 vectors. In some cases, a plasmid vector (e.g., px333 vector) comprises at least two gRNA-encoding DNA sequences. Further, a vector can comprise additional expression control sequences (e.g., enhancer sequences, Kozak sequences, polyadenylation sequences, transcriptional termination sequences, etc.), selectable marker sequences (e.g., GFP or antibiotic resistance genes such as puromycin), origins of replication, and the like. A DNA molecule encoding a gRNA can also be linear. A DNA molecule encoding a gRNA or a guide polynucleotide can also be circular.
The guide polynucleotides can comprise standard ribonucleotides, modified ribonucleotides (e.g., pseudouridine), ribonucleotide isomers, and/or ribonucleotide analogs.
In some embodiments, a base editor system may comprise multiple guide polynucleotides, e.g., gRNAs. For example, the gRNAs may target to one or more target loci (e.g., at least 1 gRNA, at least 2 gRNA, at least 5 gRNA, at least 10 gRNA, at least 20 gRNA, at least 30 g RNA, at least 50 gRNA) comprised in a base editor system. The multiple gRNA sequences can be tandemly arranged and are preferably separated by a direct repeat.
To enhance expression, stability, and/or genomic/base editing efficiency, and/or reduce possible toxicity, the base editor-coding sequence (e.g., mRNA) and/or the guide polynucleotide (e.g., gRNA) can be modified to include one or more modified nucleotides and/or chemical modifications, e.g. using pseudo-uridine, 5-Methyl-cytosine, 2′-O-methyl-3′-phosphonoacetate, 2′-O-methyl thioPACE (MSP), 2′-O-methyl-PACE (MP), 2′-fluoro RNA (2′-F-RNA), =constrained ethyl (S-cEt), 2′-O-methyl (‘M’), 2′-O-methyl-3′-phosphorothioate (‘MS’), 2′-O-methyl-3′-thiophosphonoacetate (‘MSP’), 5-methoxyuridine, phosphorothioate, and N1-Methylpseudouridine. Chemically protected gRNAs can enhance stability and editing efficiency in vivo and ex vivo. Methods for using chemically modified mRNAs and guide RNAs are known in the art and described, for example, by Jiang et al., Chemical modifications of adenine base editor mRNA and guide RNA expand its application scope. Nat Commun 11, 1979 (2020). doi.org/10.1038/s41467-020-15892-8, Callum et al., N1-Methylpseudouridine substitution enhances the performance of synthetic mRNA switches in cells, Nucleic Acids Research, Volume 48, Issue 6, 6 Apr. 2020, Page e35, and Andries et al., Journal of Controlled Release, Volume 217, 10 Nov. 2015, Pages 337-344, each of which is incorporated herein by reference in its entirety.
In some embodiments, the guide polynucleotide comprises one or more modified nucleotides at the 5′ end and/or the 3′ end of the guide. In some embodiments, the guide polynucleotide comprises two, three, four or more modified nucleosides at the 5′ end and/or the 3′ end of the guide. In some embodiments, the guide polynucleotide comprises two, three, four or more modified nucleosides at the 5′ end and/or the 3′ end of the guide.
In some embodiments, the guide comprises at least about 50/6-75% modified nucleotides. In some embodiments, the guide comprises at least about 85% or more modified nucleotides. In some embodiments, at least about 1-5 nucleotides at the 5′ end of the gRNA are modified and at least about 1-5 nucleotides at the 3′ end of the gRNA are modified. In some embodiments, at least about 3-5 contiguous nucleotides at each of the 5′ and 3′ termini of the gRNA are modified. In some embodiments, at least about 20% of the nucleotides present in a direct repeat or anti-direct repeat are modified. In some embodiments, at least about 50% of the nucleotides present in a direct repeat or anti-direct repeat are modified. In some embodiments, at least about 50-75% of the nucleotides present in a direct repeat or anti-direct repeat are modified. In some embodiments, at least about 100 of the nucleotides present in a direct repeat or anti-direct repeat are modified. In some embodiments, at least about 20% or more of the nucleotides present in a hairpin present in the gRNA scaffold are modified. In some embodiments, at least about 50% or more of the nucleotides present in a hairpin present in the gRNA scaffold are modified. In some embodiments, the guide comprises a variable length spacer. In some embodiments, the guide comprises a 20-40 nucleotide spacer. In some embodiments, the guide comprises a spacer comprising at least about 20-25 nucleotides or at least about 30-35 nucleotides. In some embodiments, the spacer comprises modified nucleotides. In some embodiments, the guide comprises two or more of the following:
In embodiments, the gRNA contains numerous modified nucleotides and/or chemical modifications (“heavy mods”). Such heavy mods can increase base editing ˜2 fold in vivo or in vitro. In embodiments, the gRNA comprises 2′-O-methyl or phosphorothioate modifications. In an embodiment, the gRNA comprises 2′-O-methyl and phosphorothioate modifications. In an embodiment, the modifications increase base editing by at least about 2 fold.
A guide polynucleotide can comprise one or more modifications to provide a nucleic acid with a new or enhanced feature. A guide polynucleotide can comprise a nucleic acid affinity tag. A guide polynucleotide can comprise synthetic nucleotide, synthetic nucleotide analog, nucleotide derivatives, and/or modified nucleotides.
A modification of a gRNA or a guide polynucleotide can be a substitution, insertion, deletion, chemical modification, physical modification, stabilization, purification, or any combination thereof.
A gRNA or a guide polynucleotide can also be modified by 5′ adenylate, 5′ guanosine-triphosphate cap, 5′ N7-Methylguanosine-triphosphate cap, 5′ triphosphate cap, 3′ phosphate, 3′ thiophosphate, 5′ phosphate, 5′ thiophosphate, Cis-Syn thymidine dimer, trimers, C12 spacer, C3 spacer, C6 spacer, dSpacer, PC spacer, rSpacer, Spacer 18, Spacer 9, 3′-3′ modifications, 2′-O-methyl thioPACE (MSP), 2′-O-methyl-PACE (MP), and constrained ethyl (S-cEt), 5′-5′ modifications, abasic, acridine, azobenzene, biotin, biotin BB, biotin TEG, cholesteryl TEG, desthiobiotin TEG, DNP TEG, DNP-X, DOTA, dT-Biotin, dual biotin, PC biotin, psoralen C2, psoralen C6, TINA, 3′ DABCYL, black hole quencher 1, black hole quencher 2, DABCYL SE, dT-DABCYL, IRDye QC-1, QSY-21, QSY-35, QSY-7, QSY-9, carboxyl linker, thiol linkers, 2′-deoxyribonucleoside analog purine, 2′-deoxyribonucleoside analog pyrimidine, ribonucleoside analog, 2′-O-methyl ribonucleoside analog, sugar modified analogs, wobble/universal bases, fluorescent dye label, 2′-fluoro RNA, 2′-O-methyl RNA, methylphosphonate, phosphodiester DNA, phosphodiester RNA, phosphothioate DNA, phosphorothioate RNA, UNA, pseudouridine-5′-triphosphate, 5′-methylcytidine-5′-triphosphate, or any combination thereof.
In some cases, a modification is permanent. In other cases, a modification is transient. In some cases, multiple modifications are made to a gRNA or a guide polynucleotide. A gRNA or a guide polynucleotide modification can alter physiochemical properties of a nucleotide, such as their conformation, polarity, hydrophobicity, chemical reactivity, base-pairing interactions, or any combination thereof.
A guide polynucleotide can be transferred into a cell by transfecting the cell with an isolated gRNA or a plasmid DNA comprising a sequence coding for the guide RNA and a promoter. A gRNA or a guide polynucleotide can also be transferred into a cell in other way, such as using virus-mediated gene delivery. A gRNA or a guide polynucleotide can be isolated. For example, a gRNA can be transfected in the form of an isolated RNA into a cell or organism. A gRNA can be prepared by in vitro transcription using any in vitro transcription system known in the art. A gRNA can be transferred to a cell in the form of isolated RNA rather than in the form of plasmid comprising encoding sequence for a gRNA.
In some cases, a phosphorothioate enhanced RNA gRNA can inhibit RNase A, RNase T1, calf serum nucleases, or any combinations thereof. These properties can allow the use of PS-RNA gRNAs to be used in applications where exposure to nucleases is of high probability in vivo or in vitro. For example, phosphorothioate (PS) bonds can be introduced between the last 3-nucleotides at the 5′- or 3′-end of a gRNA which can inhibit exonuclease degradation. In some cases, phosphorothioate bonds can be added throughout an entire gRNA to reduce attack by endonucleases.
In some embodiments, the guide RNA is designed such that base editing results in disruption of a splice site (i.e., a splice acceptor (SA) or a splice donor (SD)). In some embodiments, the guide RNA is designed such that the base editing results in a premature STOP codon.
The term “protospacer adjacent motif (PAM)” or PAM-like motif refers to a 2-6 base pair DNA sequence immediately following the DNA sequence targeted by the Cas9 nuclease in the CRISPR bacterial adaptive immune system. In some embodiments, the PAM can be a 5′ PAM (i.e., located upstream of the 5′ end of the protospacer). In other embodiments, the PAM can be a 3′ PAM (i.e., located downstream of the 5′ end of the protospacer). The PAM sequence is essential for target binding, but the exact sequence depends on a type of Cas protein. The PAM sequence can be any PAM sequence known in the art. Suitable PAM sequences include, but are not limited to, NGG, NGA, NGC, NGN, NGT, NGTT, NGCG, NGAG, NGAN, NGNG, NGCN, NGCG, NGTN, NNGRRT, NNNRRT, NNGRR(N), TTTV, TYCV, TYCV, TATV, NNNNGATT, NNAGAAW, or NAAAAC. Y is a pyrimidine; N is any nucleotide base; W is A or T.
A base editor provided herein can comprise a CRISPR protein-derived domain that is capable of binding a nucleotide sequence that contains a canonical or non-canonical protospacer adjacent motif (PAM) sequence. A PAM site is a nucleotide sequence in proximity to a target polynucleotide sequence. Some aspects of the disclosure provide for base editors comprising all or a portion (e.g., a functional portion) of CRISPR proteins that have different PAM specificities.
For example, typically Cas9 proteins, such as Cas9 from S. pyogenes (spCas9), require a canonical NGG PAM sequence to bind a particular nucleic acid region, where the “N” in “NGG” is adenine (A), thymine (T), guanine (G), or cytosine (C), and the G is guanine. A PAM can be CRISPR protein-specific and can be different between different base editors comprising different CRISPR protein-derived domains. A PAM can be 5′ or 3′ of a target sequence. A PAM can be upstream or downstream of a target sequence. A PAM can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more nucleotides in length. Often, a PAM is between 2-6 nucleotides in length.
In some embodiments, the PAM is an “NRN” PAM where the “N” in “NRN” is adenine (A), thymine (T), guanine (G), or cytosine (C), and the R is adenine (A) or guanine (G); or the PAM is an “NYN” PAM, wherein the “N” in NYN is adenine (A), thymine (T), guanine (G), or cytosine (C), and the Y is cytidine (C) or thymine (T), for example, as described in R. T. Walton et al., 2020, Science, 10.1126/science.aba8853 (2020), the entire contents of which are incorporated herein by reference.
Several PAM variants are described in Table 7 below.
In some embodiments, the PAM is NGC. In some embodiments, the NGC PAM is recognized by a Cas9 variant. In some embodiments, the NGC PAM Cas9 variant includes one or more amino acid substitutions selected from D1135M, S1136Q, G1218K, E1219F, A1322R, D1332A, R1335E, and T1337R (collectively termed “MQKFRAER(SEQ ID NO: 430)”) of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9. In some embodiments, the Cas9 variant contains one or more amino acid substitutions selected from D1135V, G1218R, R1335Q, and T1337R (collectively termed VRQR(SEQ ID NO: 424)) of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9. In some embodiments, the Cas9 variant contains one or more amino acid substitutions selected from D1135V, G1218R, R1335E, and T1337R (collectively termed VRER(SEQ ID NO: 425)) of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9. In some embodiments, the Cas9 variant contains one or more amino acid substitutions selected from E782K, N968K, and R1015H (collectively termed KHH) of saCas9 (SEQ ID NO: 218). In some embodiments, the Cas9 variant includes one or more amino acid substitutions selected from D1135M, S1136Q, G1218K, E1219S, R1335E, and T1337R (collectively termed “MQKSER(SEQ ID NO: 426)”) of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9. In some embodiments, the Cas9 variant includes one or more amino acid substitutions selected from D1135M, S1136Q, G1218K, E1219S, R1335E, and T1337R (collectively termed “MQKSER(SEQ ID NO: 426)”) of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9.
In some embodiments, the PAM is NGT. In some embodiments, the NGT PAM is recognized by a Cas9 variant. In some embodiments, the Cas9 variant is generated through targeted mutations at one or more residues 1335, 1337, 1135, 1136, 1218, and/or 1219 of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9. In some embodiments, the NGT PAM Cas9 variant is created through targeted mutations at one or more residues 1219, 1335, 1337, 1218 of spCas9 (SEQ ID No: 197), or a corresponding mutation in another Cas9. In some embodiments, the NGT PAM Cas9 variant is created through targeted mutations at one or more residues 1135, 1136, 1218, 1219, and 1335 of spCas9 (SEQ ID No: 197, or a corresponding mutation in another Cas9. In some embodiments, the Cas9 domain is a Cas9 domain from Streptococcus pyogenes (SpCas9). In some embodiments, the SpCas9 domain is a nuclease active SpCas9, a nuclease inactive SpCas9 (SpCas9d), or a SpCas9 nickase (SpCas9n). In some embodiments, the SpCas9 comprises a D9X mutation, or a corresponding mutation in any of the amino acid sequences provided herein, wherein X is any amino acid except for D. In some embodiments, the SpCas9 comprises a D9A mutation, or a corresponding mutation in any of the amino acid sequences provided herein. In some embodiments, the SpCas9 domain, the SpCas9d domain, or the SpCas9n domain can bind to a nucleic acid sequence having a non-canonical PAM. In some embodiments, the SpCas9 domain, the SpCas9d domain, or the SpCas9n domain can bind to a nucleic acid sequence having an NGG, a NGA, or a NGCG PAM sequence.
In some embodiments, the SpCas9 domain comprises one or more of a D1135X, a R1335X, and a T1337X mutation, or a corresponding mutation in any of the amino acid sequences provided herein, wherein X is any amino acid. In some embodiments, the SpCas9 domain comprises one or more of a D1135E, R1335Q, and T1337R mutation, or a corresponding mutation in any of the amino acid sequences provided herein. In some embodiments, the SpCas9 domain comprises a D1135E, a R1335Q, and a T1337R mutation, or corresponding mutations in any of the amino acid sequences provided herein.
In some examples, a PAM recognized by a CRISPR protein-derived domain of a base editor disclosed herein can be provided to a cell on a separate oligonucleotide to an insert (e.g., an AAV insert) encoding the base editor. In such embodiments, providing PAM on a separate oligonucleotide can allow cleavage of a target sequence that otherwise would not be able to be cleaved, because no adjacent PAM is present on the same polynucleotide as the target sequence.
In an embodiment, S. pyogenes Cas9 (SpCas9) can be used as a CRISPR endonuclease for genome engineering. However, others can be used. In some embodiments, a different endonuclease can be used to target certain genomic targets. In some embodiments, synthetic SpCas9-derived variants with non-NGG PAM sequences can be used. Additionally, other Cas9 orthologues from various species have been identified and these “non-SpCas9s” can bind a variety of PAM sequences that can also be useful for the present disclosure. For example, the relatively large size of SpCas9 (approximately 4 kb coding sequence) can lead to plasmids carrying the SpCas9 cDNA that cannot be efficiently expressed in a cell. Conversely, the coding sequence for Staphylococcus aureus Cas9 (SaCas9) is approximately 1 kilobase shorter than SpCas9, possibly allowing it to be efficiently expressed in a cell. Similar to SpCas9, the SaCas9 endonuclease is capable of modifying target genes in mammalian cells in vitro and in mice in vivo. In some embodiments, a Cas protein can target a different PAM sequence. In some embodiments, a target gene can be adjacent to a Cas9 PAM, 5′-NGG, for example. In other embodiments, other Cas9 orthologs can have different PAM requirements. For example, other PAMs such as those of S. thermophilus (5′-NNAGAA for CRISPR1 and 5′-NGGNG for CRISPR3) and Neisseria meningitidis (5′-NNNNGATT) can also be found adjacent to a target gene.
In some embodiments, for a S. pyogenes system, a target gene sequence can precede (i.e., be 5′ to) a 5′-NGG PAM, and a 20-nt guide RNA sequence can base pair with an opposite strand to mediate a Cas9 cleavage adjacent to a PAM. In some embodiments, an adjacent cut can be or can be about 3 base pairs upstream of a PAM. In some embodiments, an adjacent cut can be or can be about 10 base pairs upstream of a PAM. In some embodiments, an adjacent cut can be or can be about 0-20 base pairs upstream of a PAM. For example, an adjacent cut can be next to, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,or base pairs upstream of a PAM. An adjacent cut can also be downstream of a PAM by 1 to 30 base pairs. The sequences of exemplary SpCas9 proteins capable of binding a PAM sequence follow:
In some embodiments, engineered SpCas9 variants are capable of recognizing protospacer adjacent motif (PAM) sequences flanked by a 3′ H (non-G PAM). In some embodiments, the SpCas9 variants recognize NRNH PAMs (where R is A or G and H is A, C or T). In some embodiments, the non-G PAM is NRRH, NRTH, or NRCH (see e.g., Miller, S. M., et al. Continuous evolution of SpCas9 variants compatible with non-G PAMs, Nat. Biotechnol. (2020), the contents of which is incorporated herein by reference in its entirety).
In some embodiments, a variant Cas9 protein harbors, H840A, P475A, W476A, N477A, D1125A, W 1126A, and D1218A mutations relative to a reference Cas9 sequence (e.g., spCas9 (SEQ ID No: 197)), or to a corresponding mutation in another Cas9, such that the polypeptide has a reduced ability to cleave a target DNA or RNA. Such a Cas9 protein has a reduced ability to cleave a target DNA (e.g., a single stranded target DNA) but retains the ability to bind a target DNA (e.g., a single stranded target DNA). As another non-limiting example, in some embodiments, the variant Cas9 protein harbors D10A, H840A, P475A, W476A, N477A, D1125A, W1126A, and D1218A mutations relative to a reference Cas9 sequence (e.g., spCas9 (SEQ ID No: 197)), or to a corresponding mutation in another Cas9, such that the polypeptide has a reduced ability to cleave a target DNA. Such a Cas9 protein has a reduced ability to cleave a target DNA (e.g., a single stranded target DNA) but retains the ability to bind a target DNA (e.g., a single stranded target DNA). In some embodiments, when a variant Cas9 protein harbors W476A and W1126A mutations or when the variant Cas9 protein harbors P475A, W476A, N477A, D1125A, W1126A, and D1218A mutations relative to a reference Cas9 sequence (e.g., spCas9 (SEQ ID No: 197)), or to a corresponding mutation in another Cas9, the variant Cas9 protein does not bind efficiently to a PAM sequence. Thus, in some such cases, when such a variant Cas9 protein is used in a method of binding, the method does not require a PAM sequence. In other words, in some embodiments, when such a variant Cas9 protein is used in a method of binding, the method can include a guide RNA, but the method can be performed in the absence of a PAM sequence (and the specificity of binding is therefore provided by the targeting segment of the guide RNA). Other residues can be mutated to achieve the above effects (i.e., inactivate one or the other nuclease portions). As non-limiting examples, residues D10, G12, G17, E762, H840, N854, N863, H982, H983, A984, D986, and/or A987 can be altered (i.e., substituted) relative to a reference Cas9 sequence (e.g., spCas9 (SEQ ID No: 197)), or to a corresponding mutation in another Cas9. Also, mutations other than alanine substitutions are suitable.
In some embodiments, a CRISPR protein-derived domain of a base editor comprises all or a portion (e.g., a functional portion) of a Cas9 protein with a canonical PAM sequence (NGG). In other embodiments, a Cas9-derived domain of a base editor can employ a non-canonical PAM sequence. Such sequences have been described in the art and would be apparent to the skilled artisan. For example, Cas9 domains that bind non-canonical PAM sequences have been described in Kleinstiver, B. P., et al., “Engineered CRISPR-Cas9 nucleases with altered PAM specificities” Nature 523, 481-485 (2015); and Kleinstiver, B. P., et al., “Broadening the targeting range of Staphylococcus aureus CRISPR-Cas9 by modifying PAM recognition” Nature Biotechnology 33, 1293-1298 (2015); R. T. Walton et al. “Unconstrained genome targeting with near-PAMless engineered CRISPR-Cas9 variants” Science 10.1126/science.aba8853 (2020); Hu et al. “Evolved Cas9 variants with broad PAM compatibility and high DNA specificity,” Nature, 2018 Apr. 5, 556(7699), 57-63; Miller et al., “Continuous evolution of SpCas9 variants compatible with non-G PAMs” Nat. Biotechnol., 2020 April; 38(4):471-481; the entire contents of each are hereby incorporated by reference.
Fusion Proteins or Complexes Comprising a NapDNAbp and a Cytidine Deaminase and/or Adenosine Deaminase
Some aspects of the disclosure provide fusion proteins or complexes comprising a Cas9 domain or other nucleic acid programmable DNA binding protein (e.g., Cas12) and one or more cytidine deaminase, adenosine deaminase, or cytidine adenosine deaminase domains. It should be appreciated that the Cas9 domain may be any of the Cas9 domains or Cas9 proteins (e.g., dCas9 or nCas9) provided herein. In some embodiments, any of the Cas9 domains or Cas9 proteins (e.g., dCas9 or nCas9) provided herein may be fused with any of the cytidine deaminases and/or adenosine deaminases provided herein. The domains of the base editors disclosed herein can be arranged in any order.
In some embodiments, the fusion proteins or complexes comprising a cytidine deaminase or adenosine deaminase and a napDNAbp (e.g., Cas9 or Cas12 domain) do not include a linker sequence. In some embodiments, a linker is present between the cytidine or adenosine deaminase and the napDNAbp. In some embodiments, cytidine or adenosine deaminase and the napDNAbp are fused via any of the linkers provided herein. For example, in some embodiments the cytidine or adenosine deaminase and the napDNAbp are fused via any of the linkers provided herein.
It should be appreciated that the fusion proteins or complexes of the present disclosure may comprise one or more additional features. For example, in some embodiments, the fusion protein or complex may comprise inhibitors, cytoplasmic localization sequences, export sequences, such as nuclear export sequences, or other localization sequences, as well as sequence tags that are useful for solubilization, purification, or detection of the fusion proteins or complexes. Suitable protein tags provided herein include, but are not limited to, biotin carboxylase carrier protein (BCCP) tags, myc-tags, calmodulin-tags, FLAG-tags, hemagglutinin (HA)-tags, polyhistidine tags, also referred to as histidine tags or His-tags, maltose binding protein (MBP)-tags, nus-tags, glutathione-S-transferase (GST)-tags, green fluorescent protein (GFP)-tags, thioredoxin-tags, S-tags, Softags (e.g., Softag 1, Softag 3), strep-tags, biotin ligase tags, FlAsH tags, V5 tags, and SBP-tags. Additional suitable sequences will be apparent to those of skill in the art. In some embodiments, the fusion protein or complex comprises one or more His tags.
Exemplary, yet nonlimiting, fusion proteins are described in International PCT Application Nos. PCT/US2017/045381, PCT/US2019/044935, and PCT/US2020/016288, each of which is incorporated herein by reference for its entirety.
In some embodiments, the fusion proteins or complexes provided herein further comprise one or more (e.g., 2, 3, 4, 5) nuclear targeting sequences, for example a nuclear localization sequence (NLS). In one embodiment, a bipartite NLS is used. In some embodiments, a NLS comprises an amino acid sequence that facilitates the importation of a protein, that comprises an NLS, into the cell nucleus (e.g., by nuclear transport). In some embodiments, the NLS is fused to the N-terminus or the C-terminus of the fusion protein. In some embodiments, the NLS is fused to the C-terminus or N-terminus of an nCas9 domain or a dCas9 domain. In some embodiments, the NLS is fused to the N-terminus or C-terminus of the Cas12 domain. In some embodiments, the NLS is fused to the N-terminus or C-terminus of the cytidine or adenosine deaminase. In some embodiments, the NLS is fused to the fusion protein via one or more linkers. In some embodiments, the NLS is fused to the fusion protein without a linker. In some embodiments, the NLS comprises an amino acid sequence of any one of the NLS sequences provided or referenced herein. Additional nuclear localization sequences are known in the art and would be apparent to the skilled artisan. For example, NLS sequences are described in Plank et al., PCT/EP2000/011690, the contents of which are incorporated herein by reference for their disclosure of exemplary nuclear localization sequences. In some embodiments, an NLS comprises the amino acid sequence PKKKRKVEGADKRTADGSEFESPKKKRKV (SEQ ID NO: 328), KRTADGSEFESPKKKRKV (SEQ ID NO: 190), KRPAATKKAGQAKKKK (SEQ ID NO: 191), KKTELQTTNAENKTKKL (SEQ ID NO. 192), KRGINDRNFWRGENGRKTR (SEQ ID NO: 193), RKSGKIAAIVVKRPRKPKKKRKV (SEQ ID NO: 329), or MDSLLMNRRKFLYQFKNVRWAKGRRETYLC (SEQ ID NO: 196).
In some embodiments, the NLS is present in a linker or the NLS is flanked by linkers, for example described herein. A bipartite NLS comprises two basic amino acid clusters, which are separated by a relatively short spacer sequence (hence bipartite—2 parts, while monopartite NLSs are not). The NLS of nucleoplasmin, KR [PAATKKAGQA]KKKK (SEQ ID NO: 191), is the prototype of the ubiquitous bipartite signal: two clusters of basic amino acids, separated by a spacer of about 10 amino acids. The sequence of an exemplary bipartite NLS follows: PKKKRKVEGADKRTADGSEFESPKKKRKV (SEQ ID NO: 328)
A vector that encodes a CRISPR enzyme comprising one or more nuclear localization sequences (NLSs) can be used. For example, there can be or be about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 NLSs used. A CRISPR enzyme can comprise the NLSs at or near the amino-terminus, about or more than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 NLSs at or near the carboxy-terminus, or any combination thereof (e.g., one or more NLS at the amino-terminus and one or more NLS at the carboxy terminus). When more than one NLS is present, each can be selected independently of others, such that a single NLS can be present in more than one copy and/or in combination with one or more other NLSs present in one or more copies.
CRISPR enzymes used in the methods can comprise about 6 NLSs. An NLS is considered near the N- or C-terminus when the nearest amino acid to the NLS is within about 50 amino acids along a polypeptide chain from the N- or C-terminus, e.g., within 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 40, or 50 amino acids.
A base editor described herein can include any domain which helps to facilitate the nucleobase editing, modification or altering of a nucleobase of a polynucleotide. In some embodiments, a base editor comprises a polynucleotide programmable nucleotide binding domain (e.g., Cas9), a nucleobase editing domain (e.g., deaminase domain), and one or more additional domains. In some embodiments, the additional domain can facilitate enzymatic or catalytic functions of the base editor, binding functions of the base editor, or be inhibitors of cellular machinery (e.g., enzymes) that could interfere with the desired base editing result. In some embodiments, a base editor comprises a nuclease, a nickase, a recombinase, a deaminase, a methyltransferase, a methylase, an acetylase, an acetyltransferase, a transcriptional activator, or a transcriptional repressor domain.
In some embodiments, a base editor comprises an uracil glycosylase inhibitor (UGI) domain. In some embodiments, cellular DNA repair response to the presence of U: G heteroduplex DNA can be responsible for a decrease in nucleobase editing efficiency in cells. In such embodiments, uracil DNA glycosylase (UDG) can catalyze removal of U from DNA in cells, which can initiate base excision repair (BER), mostly resulting in reversion of the U:G pair to a C:G pair. In such embodiments, BER can be inhibited in base editors comprising one or more domains that bind the single strand, block the edited base, inhibit UGI, inhibit BER, protect the edited base, and/or promote repairing of the non-edited strand. Thus, this disclosure contemplates a base editor fusion protein or complex comprising a UGI domain and/or a uracil stabilizing protein (USP) domain.
In some embodiments, a base editor comprises as a domain all or a portion (e.g., a functional portion) of a double-strand break (DSB) binding protein. For example, a DSB binding protein can include a Gam protein of bacteriophage Mu that can bind to the ends of DSBs and can protect them from degradation. See Komor, A. C., et al., “Improved base excision repair inhibition and bacteriophage Mu Gam protein yields C:G-to-T:A base editors with higher efficiency and product purity” Science Advances 3:eaao4774 (2017), the entire content of which is hereby incorporated by reference.
Additionally, in some embodiments, a Gam protein can be fused to an N terminus of a base editor. In some embodiments, a Gam protein can be fused to a C terminus of a base editor. The Gam protein of bacteriophage Mu can bind to the ends of double strand breaks (DSBs) and protect them from degradation. In some embodiments, using Gam to bind the free ends of DSB can reduce indel formation during the process of base editing. In some embodiments, 174-residue Gam protein is fused to the N terminus of the base editors. See Komor, A. C., et al., “Improved base excision repair inhibition and bacteriophage Mu Gam protein yields C:G-to-T:A base editors with higher efficiency and product purity” Science Advances 3:eaao4774 (2017). In some embodiments, a mutation or mutations can change the length of a base editor domain relative to a wild type domain. For example, a deletion of at least one amino acid in at least one domain can reduce the length of the base editor. In another case, a mutation or mutations do not change the length of a domain relative to a wild type domain. For example, substitutions in any domain does not change the length of the base editor.
Provided herein are systems, compositions, and methods for editing a nucleobase using a base editor system. In some embodiments, the base editor system comprises (1) a base editor (BE) comprising a polynucleotide programmable nucleotide binding domain and a nucleobase editing domain (e.g., a deaminase domain) for editing the nucleobase; and (2) a guide polynucleotide (e.g., guide RNA) in conjunction with the polynucleotide programmable nucleotide binding domain. In some embodiments, the base editor system is a cytidine base editor (CBE) or an adenosine base editor (ABE). In some embodiments, the polynucleotide programmable nucleotide binding domain is a polynucleotide programmable DNA or RNA binding domain. In some embodiments, the nucleobase editing domain is a deaminase domain. In some embodiments, a deaminase domain can be a cytidine deaminase or an cytosine deaminase. In some embodiments, a deaminase domain can be an adenine deaminase or an adenosine deaminase. In some embodiments, the adenosine base editor can deaminate adenine in DNA. In some embodiments, the base editor is capable of deaminating a cytidine in DNA.
In some embodiments, a base editing system as provided herein provides a new approach to genome editing that uses a fusion protein or complex containing a catalytically defective Streptococcus pyogenes Cas9, a deaminase (e.g., cytidine or adenosine deaminase), and an inhibitor of base excision repair to induce programmable, single nucleotide (C→T or A→G) changes in DNA without generating double-strand DNA breaks, without requiring a donor DNA template, and without inducing an excess of stochastic insertions and deletions.
Details of nucleobase editing proteins are described in International PCT Application Nos. PCT/US2017/045381 (WO2018/027078) and PCT/US2016/058344 (WO2017/070632), each of which is incorporated herein by reference for its entirety. Also see Komor, A. C., et al., “Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage” Nature 533, 420-424 (2016); Gaudelli, N. M., et al., “Programmable base editing of A·T to G·C in genomic DNA without DNA cleavage” Nature 551, 464-471 (2017); and Komor, A. C., et al., “Improved base excision repair inhibition and bacteriophage Mu Gam protein yields C:G-to-T:A base editors with higher efficiency and product purity” Science Advances 3:eaao4774 (2017), the entire contents of which are hereby incorporated by reference.
Use of the base editor system provided herein comprises the steps of: (a) contacting a target nucleotide sequence of a polynucleotide (e.g., double- or single stranded DNA or RNA) of a subject with a base editor system comprising a nucleobase editor (e.g., an adenosine base editor or a cytidine base editor) and a guide polynucleic acid (e.g., gRNA), wherein the target nucleotide sequence comprises a targeted nucleobase pair; (b) inducing strand separation of said target region; (c) converting a first nucleobase of said target nucleobase pair in a single strand of the target region to a second nucleobase; and (d) cutting no more than one strand of said target region, where a third nucleobase complementary to the first nucleobase base is replaced by a fourth nucleobase complementary to the second nucleobase. It should be appreciated that in some embodiments, step (b) is omitted. In some embodiments, said targeted nucleobase pair is a plurality of nucleobase pairs in one or more genes. In some embodiments, the base editor system provided herein is capable of multiplex editing of a plurality of nucleobase pairs in one or more genes. In some embodiments, the plurality of nucleobase pairs is located in the same gene. In some embodiments, the plurality of nucleobase pairs is located in one or more genes, wherein at least one gene is located in a different locus.
In some embodiments, the cut single strand (nicked strand) is hybridized to the guide nucleic acid. In some embodiments, the cut single strand is opposite to the strand comprising the first nucleobase. In some embodiments, the base editor comprises a Cas9 domain. In some embodiments, the first base is adenine, and the second base is not a G, C, A, or T. In some embodiments, the second base is inosine.
In some embodiments, a single guide polynucleotide may be utilized to target a deaminase to a target nucleic acid sequence. In some embodiments, a single pair of guide polynucleotides may be utilized to target different deaminases to a target nucleic acid sequence.
The components of a base editor system (e.g., a deaminase domain, a guide RNA, and/or a polynucleotide programmable nucleotide binding domain) may be associated with each other covalently or non-covalently. For example, in some embodiments, the deaminase domain can be targeted to a target nucleotide sequence by a polynucleotide programmable nucleotide binding domain, optionally where the polynucleotide programmable nucleotide binding domain is complexed with a polynucleotide (e.g., a guide RNA). In some embodiments, a polynucleotide programmable nucleotide binding domain can be fused or linked to a deaminase domain. In some embodiments, a polynucleotide programmable nucleotide binding domain can target a deaminase domain to a target nucleotide sequence by non-covalently interacting with or associating with the deaminase domain. For example, in some embodiments, the nucleobase editing component (e.g., the deaminase component) comprises an additional heterologous portion or domain that is capable of interacting with, associating with, or capable of forming a complex with a corresponding heterologous portion, antigen, or domain that is part of a polynucleotide programmable nucleotide binding domain and/or a guide polynucleotide (e.g., a guide RNA) complexed therewith. In some embodiments, the polynucleotide programmable nucleotide binding domain, and/or a guide polynucleotide (e.g., a guide RNA) complexed therewith, comprises an additional heterologous portion or domain that is capable of interacting with, associating with, or capable of forming a complex with a corresponding heterologous portion, antigen, or domain that is part of a nucleobase editing domain (e.g., the deaminase component). In some embodiments, the additional heterologous portion may be capable of binding to, interacting with, associating with, or forming a complex with a polypeptide. In some embodiments, the additional heterologous portion may be capable of binding to, interacting with, associating with, or forming a complex with a polynucleotide. In some embodiments, the additional heterologous portion may be capable of binding to a guide polynucleotide. In some embodiments, the additional heterologous portion may be capable of binding to a polypeptide linker. In some embodiments, the additional heterologous portion is capable of binding to a polynucleotide linker. An additional heterologous portion may be a protein domain. In some embodiments, an additional heterologous portion comprises a polypeptide, such as a 22 amino acid RNA-binding domain of the lambda bacteriophage antiterminator protein N (N22p), a 2G12 IgG homodimer domain, an ABI, an antibody (e.g. an antibody that binds a component of the base editor system or a heterologous portion thereof) or fragment thereof (e.g. heavy chain domain 2 (CH2) of IgM (MHD2) or IgE (EHD2), an immunoglobulin Fc region, a heavy chain domain 3 (CH3) of IgG or IgA, a heavy chain domain 4 (CH4) of IgM or IgE, an Fab, an Fab2, miniantibodies, and/or ZIP antibodies), a barnase-barstar dimer domain, a Bcl-xL domain, a Calcineurin A (CAN) domain, a Cardiac phospholamban transmembrane pentamer domain, a collagen domain, a Com RNA binding protein domain (e.g. SfMu Com coat protein domain, and SfMu Com binding protein domain), a Cyclophilin-Fas fusion protein (CyP-Fas) domain, a Fab domain, an Fc domain, a fibritin foldon domain, an FK506 binding protein (FKBP) domain, an FKBP binding domain (FRB) domain of mTOR, a foldon domain, a fragment X domain, a GAI domain, a GIDI domain, a Glycophorin A transmembrane domain, a GyrB domain, a Halo tag, an HIV Gp41 trimerisation domain, an HPV45 oncoprotein E7 C-terminal dimer domain, a hydrophobic polypeptide, a K Homology (KH) domain, a Ku protein domain (e.g., a Ku heterodimer), a leucine zipper, a LOV domain, a mitochondrial antiviral-signaling protein CARD filament domain, an MS2 coat protein domain (MCP), a non-natural RNA aptamer ligand that binds a corresponding RNA motif/aptamer, a parathyroid hormone dimerization domain, a PP7 coat protein (PCP) domain, a PSD95-Dlgl-zo-1 (PDZ) domain, a PYL domain, a SNAP tag, a SpyCatcher moiety, a SpyTag moiety, a streptavidin domain, a streptavidin-binding protein domain, a streptavidin binding protein (SBP) domain, a telomerase Sm7 protein domain (e.g. Sm7 homoheptamer or a monomeric Sm-like protein), and/or fragments thereof. In embodiments, an additional heterologous portion comprises a polynucleotide (e.g., an RNA motif), such as an MS2 phage operator stem-loop (e.g. an MS2, an MS2 C-5 mutant, or an MS2 F-5 mutant), a non-natural RNA motif, a PP7 operator stem-loop, an SfMu phate Com stem-loop, a steril alpha motif, a telomerase Ku binding motif, a telomerase Sm7 binding motif, and/or fragments thereof. Non-limiting examples of additional heterologous portions include polypeptides with at least about 85% sequence identity to any one or more of SEQ ID NOs: 380, 382, 384, 386-388, or fragments thereof. Non-limiting examples of additional heterologous portions include polynucleotides with at least about 85% sequence identity to any one or more of SEQ ID NOs: 379, 381, 383, 385, or fragments thereof.
In some instances, components of the base editing system are associated with one another through the interaction of leucine zipper domains (e.g., SEQ ID NOs: 387 and 388). In some cases, components of the base editing system are associated with one another through polypeptide domains (e.g., FokI domains) that associate to form protein complexes containing about, at least about, or no more than about 1, 2 (i.e., dimerize), 3, 4, 5, 6, 7, 8, 9, 10 polypeptide domain units, optionally the polypeptide domains may include alterations that reduce or eliminate an activity thereof.
In some instances, components of the base editing system are associated with one another through the interaction of multimeric antibodies or fragments thereof (e.g., IgG, IgD, IgA, IgM, IgE, a heavy chain domain 2 (CH2) of IgM (MHD2) or IgE (EHD2), an immunoglobulin Fc region, a heavy chain domain 3 (CH3) of IgG or IgA, a heavy chain domain 4 (CH4) of IgM or IgE, an Fab, and an Fab2). In some instances, the antibodies are dimeric, trimeric, or tetrameric. In embodiments, the dimeric antibodies bind a polypeptide or polynucleotide component of the base editing system.
In some cases, components of the base editing system are associated with one another through the interaction of a polynucleotide-binding protein domain(s) with a polynucleotide(s). In some instances, components of the base editing system are associated with one another through the interaction of one or more polynucleotide-binding protein domains with polynucleotides that are self complementary and/or complementary to one another so that complementary binding of the polynucleotides to one another brings into association their respective bound polynucleotide-binding protein domain(s).
In some instances, components of the base editing system are associated with one another through the interaction of a polypeptide domain(s) with a small molecule(s) (e.g., chemical inducers of dimerization (CIDs), also known as “dimerizers”). Non-limiting examples of CIDs include those disclosed in Amara, et al., “A versatile synthetic dimerizer for the regulation of protein-protein interactions,” PNAS, 94:10618-10623 (1997); and Voβ, et al. “Chemically induced dimerization: reversible and spatiotemporal control of protein function in cells,” Current Opinion in Chemical Biology, 28:194-201 (2015), the disclosures of each of which are incorporated herein by reference in their entireties for all purposes. Non-limiting examples of polypeptides that can dimerize and their corresponding dimerizing agents are provided in Table 8 below.
In embodiments, the additional heterologous portion is part of a guide RNA molecule. In some instances, the additional heterologous portion contains or is an RNA motif. The RNA motif may be positioned at the 5′ or 3′ end of the guide RNA molecule or various positions of a guide RNA molecule. In embodiments, the RNA motif is positioned within the guide RNA to reduce steric hindrance, optionally where such hindrance is associated with other bulky loops of an RNA scaffold. In some instances, it is advantageous to link the RNA motif is linked to other portions of the guide RNA by way of a linker, where the linker can be about, at least about, or no more than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more nucleotides in length. Optionally, the linker contains a GC-rich nucleotide sequence. The guide RNA can contain 1, 2, 3, 4, 5, or more copies of the RNA motif, optionally where they are positioned consecutively, and/or optionally where they are each separated from one another by a linker(s). The RNA motif may include any one or more of the polynucleotide modifications described herein. Non-limiting examples of suitable modifications to the RNA motif include 2′ deoxy-2-aminopurine, 2′ribose-2-aminopurine, phosphorothioate mods, 2′-Omethyl mods, 2′-Fluro mods and LNA mods. Advantageously, the modifications help to increase stability and promote stronger bonds/folding structure of a hairpin(s) formed by the RNA motif.
In some embodiments, the RNA motif is modified to include an extension. In embodiments, the extension contains about, at least about, or no more than about 2, 3, 4, 5, 10, 15, 20, or 25 nucleotides. In some instances, the extension results in an alteration in the length of a stem formed by the RNA motif (e.g., a lengthening or a shortening). It can be advantageous for a stem formed by the RNA motif to be about, at least about, or no more than about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 nucleotides in length. In various embodiments, the extension increases flexibility of the RNA motif and/or increases binding with a corresponding RNA motif.
In some embodiments, the base editor inhibits base excision repair (BER) of the edited strand. In some embodiments, the base editor protects or binds the non-edited strand. In some embodiments, the base editor comprises UGI activity or USP activity. In some embodiments, the base editor comprises a catalytically inactive inosine-specific nuclease. In some embodiments, the base editor comprises nickase activity. In some embodiments, the intended edit of base pair is upstream of a PAM site. In some embodiments, the intended edit of base pair is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 nucleotides upstream of the PAM site. In some embodiments, the intended edit of base-pair is downstream of a PAM site. In some embodiments, the intended edited base pair is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 nucleotides downstream stream of the PAM site.
In some embodiments, the method does not require a canonical (e.g., NGG) PAM site. In some embodiments, the nucleobase editor comprises a linker or a spacer. In some embodiments, the linker or spacer is 1-25 amino acids in length. In some embodiments, the linker or spacer is 5-20 amino acids in length. In some embodiments, the linker or spacer is 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 amino acids in length.
The base editors of the present disclosure can comprise any domain, feature or amino acid sequence which facilitates the editing of a target polynucleotide sequence. For example, in some embodiments, the base editor comprises a nuclear localization sequence (NLS). In some embodiments, an NLS of the base editor is localized between a deaminase domain and a polynucleotide programmable nucleotide binding domain. In some embodiments, an NLS of the base editor is localized C-terminal to a polynucleotide programmable nucleotide binding domain.
Protein domains included in the fusion protein can be a heterologous functional domain. Non-limiting examples of protein domains which can be included in the fusion protein include a deaminase domain (e.g., cytidine deaminase and/or adenosine deaminase), a uracil glycosylase inhibitor (UGI) domain, epitope tags, and reporter gene sequences. Protein domains can be a heterologous functional domain, for example, having one or more of the following activities. transcriptional activation activity, transcriptional repression activity, transcription release factor activity, gene silencing activity, chromatin modifying activity, epigenetic modifying activity, histone modification activity, RNA cleavage activity, and nucleic acid binding activity. Such heterologous functional domains can confer a function activity, such as modification of a target polypeptide associated with target DNA (e.g., a histone, a DNA binding protein, etc.), leading to, for example, histone methylation, histone acetylation, histone ubiquitination, and the like. Other functions and/or activities conferred can include transposase activity, integrase activity, recombinase activity, ligase activity, ubiquitin ligase activity, deubiquitinating activity, adenylation activity, deadenylation activity, methyltransferase activity, demethylase activity, acetyltransferase activity, deacetylase activity, kinase activity, phosphatase activity, ribosylation activity, deribosylation activity, myristoylation activity, demyristoylation activity, polymerase activity, helicase activity, or nuclease activity, SUMOylation activity, deSUMOylation activity, or any combination of the above. In some embodiments, the Cas9 protein is fused to a histone demethylase, a transcriptional activator or a deaminase.
Further suitable fusion partners include, but are not limited to boundary elements (e.g., CTCF), proteins and fragments thereof that provide periphery recruitment (e.g., Lamin A, Lamin B, etc.), and protein docking elements (e.g., FKBP/FRB, Pill/Abyl, etc.).
In some embodiments, non-limiting exemplary cytidine base editors (CBE) include BE1 (APOBEC1-XTEN-dCas9), BE2 (APOBEC1-XTEN-dCas9-UGI), BE3 (APOBEC1-XTEN-dCas9(A840H)-UGI), BE3-Gam, saBE3, saBE4-Gam, BE4, BE4-Gam, saBE4, or saB4E-Gam. BE4 extends the APOBEC1-Cas9n(D10A) linker to 32 amino acids and the Cas9n-UGI linker to 9 amino acids, and appends a second copy of UGI to the C-terminus of the construct with another 9-amino acid linker into a single base editor construct. The base editors saBE3 and saBE4 have the S. pyogenes Cas9n(D10A) replaced with the smaller S, aureus Cas9n(D10A). BE3-Gam, saBE3-Gam, BE4-Gam, and saBE4-Gam have 174 residues of Gam protein fused to the N-terminus of BE3, saBE3, BE4, and saBE4 via the 16 amino acid XTEN linker.
In some embodiments, the adenosine base editor (ABE) can deaminate adenine in DNA. In some embodiments, ABE is generated by replacing APOBEC1 component of BE3 with natural or engineered E. coli TadA, human ADAR2, mouse ADA, or human ADAT2. In some embodiments, ABE comprises evolved TadA variant. In some embodiments, the ABE is ABE 1.2 (TadA*-XTEN-nCas9-NLS). In some embodiments, TadA* comprises A106V and D108N mutations. PGP 84,T2.M
In some embodiments, the ABE is selected from those listed in Table 9 below.
In some embodiments, the base editor is an eighth generation ABE (ABE8). In some embodiments, the ABE8 contains a TadA*8 variant.
In some embodiments, the ABE is an ARE8 variant listed in Table 10 below.
In some embodiments, the ABE8 is an ABE8 variant listed in Table 11 below. In addition to the mutations shown for ABE8e in Table 11, off-target RNA and DNA editing were reduced by introducing aV106W substitution into the TadA domain (as described in M. Richter ea al., 2020, Nature Biotechnology, doi.org/10.1038/s41587-020-0453-z, the entire contents of which are incorporated b reference herein.
In some embodiments, base editors (e.g., ABE8) are generated by cloning an adenosine deaminase variant (e.g., TadA*8) into a scaffold that includes a circular permutant Cas9 (e.g., CP5 or CP6) and a bipartite nuclear localization sequence. In some embodiments, the base editor (e.g., ABE7.9, ABE7.10, or ABE8) is an NGC PAM CP5 variant (S. pyogenes Cas9 or spVRQR (SEQ ID NO: 424) Cas9). In some embodiments, the base editor (e.g., ABE7.9, ABE7.10, or ABE8) is an AGA PAM CP5 variant (S. pyogenes Cas9 or spVRQR(SEQ ID NO: 424) Cas9). In some embodiments, the base editor (e.g., ABE7.9, ABE7.10, or ABE8) is an NGC PAM CP6 variant (S. pyogenes Cas9 or spVRQR (SEQ ID NO: 424)Cas9). In some embodiments, the base editor (e.g. ABE7.9, ABE7.10, or ABE8) is an AGA PAM CP6 variant (S. pyogenes Cas9 or spVRQR (SEQ ID NO: 424)Cas9).
In some embodiments, the ABE has a genotype as shown in Table 12 below.
As shown in Table 13 below, genotypes of 40 ABE8s are described. Residue positions in the evolved E. coli TadA portion of ABE are indicated. Mutational changes in ABE8 are shown when distinct from ABE7.10 mutations. In some embodiments, the ABE has a genotype of one of the ABEs as shown in Table 13 below.
In some embodiments, the base editor is ABE8.1, which comprises or consists essentially of the following sequence or a fragment thereof having adenosine deaminase activity:
IGKATAKYFFYSNIMNFFKTEITLANGEIRKRPLIETNGETGEIVWDKGR
DFATVRKVLSMPQVNIVKKTEVQTGGFSKESILPKRNSDKLIARKKDWDP
KKYGGFMQPTVAYSVLVVAKVEKGKSKKLKSVKELLGITIMERSSFEKNP
IDFLEAKGYKEVKKDLIIKLPKYSLFELENGRKRMLASAKFLQKGNELAL
PSKYVNFLYLASHYEKLKGSPEDNEQKQLFVEQHKHYLDEIIEQISEFSK
RVILADANLDKVLSAYNKHRDKPIREQAENIIHLFTLTNLGAPRAFKYFD
TTIARKEYRSTKEVLDATLIHQSITGLYETRIDLSQLGGD
GGSGGSGGSG
GSGGSGGSGGM
DKKYSIGLAIGTNSVGWAVITDEYKVPSKKFKVLGNTDR
HSIKKNLIGALLFDSGETAEATRLKRTARRRYTRRKNRICYLQEIFSNEM
AKVDDSFFHRLEESFLVEEDKKHERHPIFGNIVDEVAYHEKYPTIYHLRK
KLVDSTDKADLRLIYLALAHMIKFRGHFLIEGDLNPDNSDVDKLFIQLVQ
TYNQLFEENPINASGVDAKAILSARLSKSRRLENLIAQLPGEKKNGLFGN
LIALSLGLTPNFKSNFDLAEDAKLQLSKDTYDDDLDNLLAQIGDQYADLF
LAAKNLSDAILLSDILRVNTEITKAPLSASMIKRYDEHHQDLTLLKALVR
QQLPEKYKEIFFDQSKNGYAGYIDGGASQEEFYKFIKPILEKMDGTEELL
VKLNREDLLRKQRTFDNGSIPHQIHLGELHAILRRQEDFYPFLKDNREKI
EKILTFRIPYYVGPLARGNSRFAWMTRKSEETITPWNFEEVVDKGASAQS
FIERMTNFDKNLPNEKVLPKHSLLYEYFTVYNELTKVKYVTEGMRKPAFL
SGEQKKAIVDLLFKTNRKVTVKQLKEDYFKKIECFDSVEISGVEDRFNAS
LGTYHDLLKIIKDKDFLDNEENEDILEDIVLTLTLFEDREMIEERLKTYA
HLFDDKVMKQLKRRRYTGWGRLSRKLINGIRDKQSGKTILDFLKSDGFAN
RNFMQLIHDDSLTFKEDIQKAQVSGQGDSLHEHIANLAGSPAIKKGILQT
VKVVDELVKVMGRHKPENIVIEMARENQTTQKGQKNSRERMKRIEEGIKE
LGSQILKEHPVENTQLQNEKLYLYYLQNGRDMYVDQELDINRLSDYDVDH
IVPQSFLKDDSIDNKVLTRSDKNRGKSDNVPSEEVVKKMKNYWRQLLNAK
LITQRKFDNLTKAERGGLSELDKAGFIKRQLVETRQITKHVAQILDSRMN
TKYDENDKLIREVKVITLKSKLVSDFRKDFQFYKVREINNYHHAHDAYLN
AVVGTALIKKYPKLESEFVYGDYKVYDVRKMIAKSEQ
EGADKRTADGSEF
ESPKKKRKV
In the above sequence, the plain text denotes an adenosine deaminase sequence, bold sequence indicates sequence derived from Cas9, the italicized sequence denotes a linker sequence, and the underlined sequence denotes a bipartite nuclear localization sequence. Other ABE8 sequences are provided in the attached sequence listing (SEQ ID NOs: 332-354).
In some embodiments, the base editor is a ninth generation ABE (ABE9). Exemplary ABE9 variants are listed in Table 14. Details of ABE9 base editors are described in International PCT Application No. PCT/US2020/049975, which is incorporated herein by reference for its entirety.
In some embodiments, the base editor includes an adenosine deaminase variant comprising an amino acid sequence, which contains alterations relative to an ABE7*10 reference sequence, as described herein. The term “monomer” as used in Table 15 refers to a monomeric form of TadA*7.10 comprising the alterations described. The term “heterodimer” as used in Table 15 refers to the specified wild-type E. coli TadA adenosine deaminase fused to a TadA*7.10 comprising the alterations as described.
In some embodiments, the base editor comprises a domain comprising all or a portion (e.g., a functional portion) of a uracil glycosylase inhibitor (UGI) or a uracil stabilizing protein (USP) domain.
In some embodiments, a domain of the base editor comprises multiple domains. For example, the base editor comprising a polynucleotide programmable nucleotide binding domain derived from Cas9 can comprise a REC lobe and an NUC lobe corresponding to the REC lobe and NUC lobe of a wild-type or natural Cas9. In another example, the base editor can comprise one or more of a RuvCI domain, BH domain, REC1 domain, REC2 domain, RuvCII domain, L1 domain, HNH domain, L2 domain, RuvCIII domain, WED domain, TOPO domain or CTD domain. In some embodiments, one or more domains of the base editor comprise a mutation (e.g., substitution, insertion, deletion) relative to a wild-type version of a polypeptide comprising the domain.
Different domains (e.g., adjacent domains) of the base editor disclosed herein can be connected to each other with or without the use of one or more linker domains (e.g., an XTEN linker domain). In some embodiments, a linker domain can be a bond (e.g., covalent bond), chemical group, or a molecule linking two molecules or moieties, e.g., two domains of a fusion protein, such as, for example, a first domain (e.g., Cas9-derived domain) and a second domain (e.g., an adenosine deaminase domain or a cytidine deaminase domain. In some embodiments, a linker joins a gRNA binding domain of an RNA-programmable nuclease, including a Cas9 nuclease domain, and the catalytic domain of a nucleic acid editing protein. In some embodiments, a linker joins a dCas9 and a second domain (e.g., UGI, etc.).
In certain embodiments, linkers may be used to link any of the peptides or peptide domains of the invention. The linker may be as simple as a covalent bond, or it may be a polymeric linker many atoms in length. In certain embodiments, the linker is a polypeptide or based on amino acids. In other embodiments, the linker is not peptide-like. In certain embodiments, the linker is a covalent bond (e.g., a carbon-carbon bond, disulfide bond, carbon-heteroatom bond, etc.). In certain embodiments, the linker is a carbon-nitrogen bond of an amide linkage. In certain embodiments, the linker is a cyclic or acyclic, substituted or unsubstituted, branched or unbranched aliphatic or heteroaliphatic linker. In certain embodiments, the linker is polymeric (e.g., polyethylene, polyethylene glycol, polyamide, polyester, etc.). In certain embodiments, the linker comprises a monomer, dimer, or polymer of aminoalkanoic acid. In certain embodiments, the linker comprises an aminoalkanoic acid (e.g., glycine, ethanoic acid, alanine, beta-alanine, 3-aminopropanoic acid, 4-aminobutanoic acid, 5-pentanoic acid, etc.). In certain embodiments, the linker comprises a monomer, dimer, or polymer of aminohexanoic acid (Ahx). In certain embodiments, the linker is based on a carbocyclic moiety (e.g., cyclopentane, cyclohexane). In other embodiments, the linker comprises a polyethylene glycol moiety (PEG). In other embodiments, the linker comprises amino acids. In certain embodiments, the linker comprises a peptide. In certain embodiments, the linker comprises an aryl or heteroaryl moiety. In certain embodiments, the linker is based on a phenyl ring. The linker may include functionalized moieties to facilitate attachment of a nucleophile (e.g., thiol, amino) from the peptide to the linker. Any electrophile may be used as part of the linker. Exemplary electrophiles include, but are not limited to, activated esters, activated amides, Michael acceptors, alkyl halides, aryl halides, acyl halides, and isothiocyanates.
Typically, a linker is positioned between, or flanked by, two groups, molecules, or other moieties and connected to each one via a covalent bond, thus connecting the two. In some embodiments, a linker is an amino acid or a plurality of amino acids (e.g., a peptide or protein). In some embodiments, a linker is an organic molecule, group, polymer, or chemical moiety. In some embodiments, a linker is 2-100 amino acids in length.
In some embodiments, any of the fusion proteins provided herein, comprise a cytidine or adenosine deaminase and a Cas9 domain that are fused to each other via a linker. Various linker lengths and flexibilities between the cytidine or adenosine deaminase and the Cas9 domain can be employed (e.g., ranging from very flexible linkers of the form (GGGS) n (SEQ ID NO: 415), (GGGGS)n (SEQ ID NO: 416), and (G)n (SEQ ID NO: 418) to more rigid linkers of the form (EAAAK)n (SEQ ID NO: 417), (SGGS)n (SEQ ID NO: 420), SGSETPGTSESATPES (SEQ ID NO: 249) (see, e.g., Guilinger J P, et al. Fusion of catalytically inactive Cas9 to FokI nuclease improves the specificity of genome modification. Nat. Biotechnol. 2014; 32(6): 577-82; the entire contents are incorporated herein by reference) and (XP)n(SEQ ID NO: 421)) in order to achieve the optimal length for activity for the cytidine or adenosine deaminase nucleobase editor. In some embodiments, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. In some embodiments, the linker comprises a (GGS)n(SEQ ID NO: 422, 423) motif, wherein n is 1, 3, or 7. In some embodiments, cytidine deaminase or adenosine deaminase and the Cas9 domain of any of the fusion proteins provided herein are fused via a linker comprising the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 249), which can also be referred to as the XTEN linker.
In some embodiments, the domains of the base editor are fused via a linker that comprises the amino acid sequence of:
In some embodiments, domains of the base editor are fused via a linker comprising the amino acid sequence SGSETPGTSESATPES (SEQ ID NO: 249), which may also be referred to as the XTEN linker. In some embodiments, a linker comprises the amino acid sequence SGGS (SEQ ID NO: 355). In some embodiments, the linker is 24 amino acids in length. In some embodiments, the linker comprises the amino acid sequence SGGSSGGSSGSETPGTSESATPES (SEQ ID NO: 359). In some embodiments, the linker is 40 amino acids in length. In some embodiments, the linker comprises the amino acid sequence: SGGSSGGSSGSETPGTSESATPESSGGSSGGSSGGSSGGS (SEQ ID NO: 360). In some embodiments, the linker is 64 amino acids in length. In some embodiments, the linker comprises the amino acid sequence: SGGSSGGSSGSETPGTSESATPESSGGSSGGSSGGSSGGSSGSETPGTSESATPESSGGSSGGS (SEQ ID NO: 361). In some embodiments, the linker is 92 amino acids in length. In some embodiments, the linker comprises the amino acid sequence:
In some embodiments, a linker comprises a plurality of proline residues and is 5-21, 5-14, 5-9, 5-7 amino acids in length, e.g., PAPAP (SEQ ID NO: 363), PAPAPA (SEQ ID NO: 364), PAPAPAP (SEQ ID NO: 365), PAPAPAPA (SEQ ID NO: 366), P(AP)4 (SEQ ID NO: 367), P(AP)7 (SEQ ID NO: 368), P(AP)10 (SEQ ID NO. 369) (see, e.g., Tan J, Zhang F, Karcher D, Bock R. Engineering of high-precision base editors for site-specific single nucleotide replacement. Nat Commun. 2019 Jan. 25; 10(1):439; the entire contents are incorporated herein by reference). Such proline-rich linkers are also termed “rigid” linkers.
In another embodiment, the base editor system comprises a component (protein) that interacts non-covalently with a deaminase (DNA deaminase), e.g., an adenosine or a cytidine deaminase, and transiently attracts the adenosine or cytidine deaminase to the target nucleobase in a target polynucleotide sequence for specific editing, with minimal or reduced bystander or target-adjacent effects. Such a non-covalent system and method involving deaminase-interacting proteins serves to attract a DNA deaminase to a particular genomic target nucleobase and decouples the events of on-target and target-adjacent editing, thus enhancing the achievement of more precise single base substitution mutations. In an embodiment, the deaminase-interacting protein binds to the deaminase (e.g., adenosine deaminase or cytidine deaminase) without blocking or interfering with the active (catalytic) site of the deaminase from engaging the target nucleobase (e.g., adenosine or cytidine, respectively). Such as system, termed “MagnEdit,” involves interacting proteins tethered to a Cas9 and gRNA complex and can attract a co-expressed adenosine or cytidine deaminase (either exogenous or endogenous) to edit a specific genomic target site, and is described in McCann, J. et al., 2020, “MagnEdit—interacting factors that recruit DNA-editing enzymes to single base targets,” Life-Science-Alliance, Vol. 3, No. 4 (e201900606), (doi 10.26508/Isa.201900606), the contents of which are incorporated by reference herein in their entirety. In an embodiment, the DNA deaminase is an adenosine deaminase variant (e.g., TadA*8) as described herein.
In another embodiment, a system called “Suntag,” involves non-covalently interacting components used for recruiting protein (e.g., adenosine deaminase or cytidine deaminase) components, or multiple copies thereof, of base editors to polynucleotide target sites to achieve base editing at the site with reduced adjacent target editing, for example, as described in Tanenbaum, M. E. et al., “A protein tagging system for signal amplification in gene expression and fluorescence imaging,” Cell. 2014 Oct. 23; 159(3): 635-646.doi:10.1016/j.cell.2014.09.039; and in Huang, Y.-H. et al., 2017, “DNA epigenome editing using CRISPR-Cas SunTag-directed DNMT3A,” Genome Biol 18: 176. doi:10.1186/s13059-017-1306-z, the contents of each of which are incorporated by reference herein in their entirety. In an embodiment, the DNA deaminase is an adenosine deaminase variant (e.g., TadA*8) as described herein.
Nucleic Acid Programmable DNA Binding Proteins with Guide RNAs
Provided herein are compositions and methods for base editing in cells. Further provided herein are compositions comprising a guide polynucleic acid sequence, e.g. a guide RNA sequence, or a combination of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more guide RNAs as provided herein. In some embodiments, a composition for base editing as provided herein further comprises a polynucleotide that encodes a base editor, e.g. a C-base editor or an A-base editor. For example, a composition for base editing may comprise a mRNA sequence encoding a BE, a BE4, an ABE, and a combination of one or more guide RNAs as provided. A composition for base editing may comprise a base editor polypeptide and a combination of one or more of any guide RNAs provided herein. Such a composition may be used to effect base editing in a cell through different delivery approaches, for example, electroporation, nucleofection, viral transduction or transfection. In some embodiments, the composition for base editing comprises an mRNA sequence that encodes a base editor and a combination of one or more guide RNA sequences provided herein for electroporation.
Some aspects of this disclosure provide systems comprising any of the fusion proteins or complexes provided herein, and a guide RNA bound to a nucleic acid programmable DNA binding protein (napDNAbp) domain (e.g., a Cas9 (e.g., a dCas9, a nuclease active Cas9, or a Cas9 nickase) or Cas12) of the fusion protein or complex. These complexes are also termed ribonucleoproteins (RNPs). In some embodiments, the guide nucleic acid (e.g., guide RNA) is from 15-100 nucleotides long and comprises a sequence of at least 10 contiguous nucleotides that is complementary to a target sequence. In some In some embodiments, the target sequence is a DNA sequence. In some embodiments, the target sequence is an RNA sequence. In some embodiments, the target sequence is a sequence in the genome of a bacteria, yeast, fungi, insect, plant, or animal. In some embodiments, the target sequence is a sequence in the genome of a human. In some embodiments, the 3′ end of the target sequence is immediately adjacent to a canonical PAM sequence (NGG). In some embodiments, the 3′ end of the target sequence is immediately adjacent to a non-canonical PAM sequence (e.g., a sequence listed in Table 7 or 5′-NAA-3′). In some embodiments, the guide nucleic acid (e.g., guide RNA) is complementary to a sequence in a gene of interest (e.g., a gene associated with a disease or disorder).
Some aspects of this disclosure provide methods of using the fusion proteins, or complexes provided herein. For example, some aspects of this disclosure provide methods comprising contacting a DNA molecule with any of the fusion proteins or complexes provided herein, and with at least one guide RNA, wherein the guide RNA is about 15-100 nucleotides long and comprises a sequence of at least 10 contiguous nucleotides that is complementary to a target sequence.
It will be understood that the numbering of the specific positions or residues in the respective sequences depends on the particular protein and numbering scheme used. Numbering might differ, e.g., in precursors of a mature protein and the mature protein itself, and differences in sequences from species to species may affect numbering. One of skill in the art will be able to identify the respective residue in any homologous protein and in the respective encoding nucleic acid by methods well known in the art, e.g., by sequence alignment and determination of homologous residues.
It will be apparent to those of skill in the art that in order to target any of the fusion proteins or complexes disclosed herein, to a target site, e.g., a site comprising a mutation to be edited, it is typically necessary to co-express the fusion protein or complex together with a guide RNA. As explained in more detail elsewhere herein, a guide RNA typically comprises a tracrRNA framework allowing for napDNAbp (e.g., Cas9 or Cas12) binding, and a guide sequence, which confers sequence specificity to the napDNAbp:nucleic acid editing enzyme/domain fusion protein or complex. Alternatively, the guide RNA and tracrRNA may be provided separately, as two nucleic acid molecules. In some embodiments, the guide RNA comprises a structure, wherein the guide sequence comprises a sequence that is complementary to the target sequence. The guide sequence is typically 20 nucleotides long. The sequences of suitable guide RNAs for targeting napDNAbp:nucleic acid editing enzyme/domain fusion proteins or complexes to specific genomic target sites will be apparent to those of skill in the art based on the instant disclosure. Such suitable guide RNA sequences typically comprise guide sequences that are complementary to a nucleic sequence within 50 nucleotides upstream or downstream of the target nucleotide to be edited. Some exemplary guide RNA sequences suitable for targeting any of the provided fusion proteins or complexes to specific target sequences are provided herein.
The domains of the base editor disclosed herein can be arranged in any order.
In some embodiments, the base editing fusion proteins or complexes provided herein need to be positioned at a precise location, for example, where a target base is placed within a defined region (e.g., a “deamination window”). In some embodiments, a target can be within a 4-base region. In some embodiments, such a defined target region can be approximately 15 bases upstream of the PAM. See Komor, A. C., et al., “Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage” Nature 533, 420-424 (2016); Gaudelli, N. M., et al., “Programmable base editing of A·T to G·C in genomic DNA without DNA cleavage” Nature 551, 464-471 (2017); and Komor, A. C., et al., “Improved base excision repair inhibition and bacteriophage Mu Gain protein yields C:G-to-T:A base editors with higher efficiency and product purity” Science Advances 3:eaao4774 (2017), the entire contents of which are hereby incorporated by reference.
A defined target region can be a deamination window. A deamination window can be the defined region in which a base editor acts upon and deaminates a target nucleotide. In some embodiments, the deamination window is within a 2, 3, 4, 5, 6, 7, 8, 9, or 10 base regions. In some embodiments, the deamination window is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 bases upstream of the PAM.
The base editors of the present disclosure can comprise any domain, feature or amino acid sequence which facilitates the editing of a target polynucleotide sequence.
Non-limiting examples of protein domains which can be included in the fusion protein or complex include a deaminase domain (e.g., adenosine deaminase or cytidine deaminase), a uracil glycosylase inhibitor (UGI) domain, epitope tags, reporter gene sequences, and/or protein domains having one or more of the activities described herein.
Some aspects of this disclosure provide methods of using the fusion proteins, or complexes provided herein. For example, some aspects of this disclosure provide methods comprising contacting a DNA molecule with any of the fusion proteins or complexes provided herein, and with at least one guide RNA described herein.
In some embodiments, a fusion protein or complex of the invention is used for editing a target gene of interest. In particular, a cytidine deaminase or adenosine deaminase nucleobase editor described herein is capable of making multiple mutations within a target sequence. These mutations may affect the function of the target. For example, when a cytidine deaminase or adenosine deaminase nucleobase editor is used to target a regulatory region the function of the regulatory region is altered and the expression of the downstream protein is reduced or eliminated.
It will be understood that the numbering of the specific positions or residues in the respective sequences depends on the particular protein and numbering scheme used. Numbering might be different, e.g., in precursors of a mature protein and the mature protein itself, and differences in sequences from species to species may affect numbering. One of skill in the art will be able to identify the respective residue in any homologous protein and in the respective encoding nucleic acid by methods well known in the art, e.g., by sequence alignment and determination of homologous residues.
In some embodiments, the purpose of the methods provided herein is to alter a gene and/or gene product via gene editing. The nucleobase editing proteins provided herein can be used for gene editing-based human therapeutics in vitro or in vivo. It will be understood by the skilled artisan that the nucleobase editing proteins provided herein, e.g., the fusion proteins or complexes comprising a polynucleotide programmable nucleotide binding domain (e.g., Cas9) and a nucleobase editing domain (e.g., an adenosine deaminase domain or a cytidine deaminase domain) can be used to edit a nucleotide from A to G or C to T.
Advantageously, base editing systems as provided herein provide genome editing without generating double-strand DNA breaks, without requiring a donor DNA template, and without inducing an excess of stochastic insertions and deletions as CRISPR may do. In some embodiments, the present disclosure provides base editors that efficiently generate an intended mutation, such as a STOP codon, in a nucleic acid (e.g., a nucleic acid within a genome of a subject) without generating a significant number of unintended mutations, such as unintended point mutations. In some embodiments, an intended mutation is a mutation that is generated by a specific base editor (e.g., adenosine base editor or cytidine base editor) bound to a guide polynucleotide (e.g., gRNA), specifically designed to generate the intended mutation. In some embodiments, the intended mutation is in a gene associated a disease or disorder. In some embodiments, the intended mutation is an adenine (A) to guanine (G) point mutation (e.g., SNP) in a gene associated with a disease or disorder. In some embodiments, the intended mutation is an adenine (A) to guanine (G) point mutation within the coding region or non-coding region of a gene (e.g., regulatory region or element). In some embodiments, the intended mutation is a cytosine (C) to thymine (T) point mutation (e.g., SNP) in a gene associated with a disease or disorder. In some embodiments, the intended mutation is a cytosine (C) to thymine (T) point mutation within the coding region or non-coding region of a gene (e.g., regulatory region or element). In some embodiments, the intended mutation is a point mutation that generates a STOP codon, for example, a premature STOP codon within the coding region of a gene. In some embodiments, the intended mutation is a mutation that eliminates a stop codon.
The base editors of the invention advantageously modify a specific nucleotide base encoding a protein without generating a significant proportion of indels (i.e., insertions or deletions). Such indels can lead to frame shift mutations within a coding region of a gene. In some embodiments, it is desirable to generate base editors that efficiently modify (e.g., mutate) a specific nucleotide within a nucleic acid, without generating a large number of insertions or deletions (i.e., indels) in the nucleic acid. In some embodiments, it is desirable to generate base editors that efficiently modify (e.g., mutate or methylate) a specific nucleotide within a nucleic acid, without generating a large number of insertions or deletions (i.e., indels) in the nucleic acid. In certain embodiments, any of the base editors provided herein can generate a greater proportion of intended modifications (e.g., methylations) versus indels. In certain embodiments, any of the base editors provided herein can generate a greater proportion of intended modifications (e.g., mutations) versus indels.
In some embodiments, the base editors provided herein are capable of generating a ratio of intended mutations to indels (i.e., intended point mutations:unintended point mutations) that is greater than 1:1. In some embodiments, the base editors provided herein are capable of generating a ratio of intended mutations to indels that is at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at least 3.5:1, at least 4:1, at least 4.5:1, at least 5:1, at least 5.5:1, at least 6:1, at least 6.5:1, at least 7:1, at least 7.5:1, at least 8:1, at least 10:1, at least 12:1, at least 15:1, at least 20:1, at least 25:1, at least 30:1, at least 40:1, at least 50:1, at least 100:1, at least 200:1, at least 300:1, at least 400:1, at least 500:1, at least 600:1, at least 700:1, at least 800:1, at least 900:1, or at least 1000:1, or more. The number of intended mutations and indels may be determined using any suitable method.
In some embodiments, the base editors provided herein can limit formation of indels in a region of a nucleic acid. In some embodiments, the region is at a nucleotide targeted by a base editor or a region within 2, 3, 4, 5, 6, 7, 8, 9, or 10 nucleotides of a nucleotide targeted by a base editor. In some embodiments, any of the base editors provided herein can limit the formation of indels at a region of a nucleic acid to less than 1%, less than 1.5%, less than 2%, less than 2.5%, less than 3%, less than 3.5%, less than 4%, less than 4.5%, less than 5%, less than 6%, less than 7%, less than 8%, less than 9%, less than 10/6, less than 12%, less than 15%, or less than 20%. The number of indels formed at a nucleic acid region may depend on the amount of time a nucleic acid (e.g., a nucleic acid within the genome of a cell) is exposed to a base editor. In some embodiments, a number or proportion of indels is determined after at least 1 hour, at least 2 hours, at least 6 hours, at least 12 hours, at least 24 hours, at least 36 hours, at least 48 hours, at least 3 days, at least 4 days, at least 5 days, at least 7 days, at least 10 days, or at least 14 days of exposing a nucleic acid (e.g., a nucleic acid within the genome of a cell) to a base editor.
Some aspects of the disclosure are based on the recognition that any of the base editors provided herein are capable of efficiently generating an intended mutation in a nucleic acid (e.g. a nucleic acid within a genome of a subject) without generating a considerable number of unintended mutations (e.g., spurious off-target editing or bystander editing). In some embodiments, an intended mutation is a mutation that is generated by a specific base editor bound to a gRNA, specifically designed to generate the intended mutation. In some embodiments, the intended mutation is a mutation that generates a stop codon, for example, a premature stop codon within the coding region of a gene. In some embodiments, the intended mutation is a mutation that eliminates a stop codon. In some embodiments, the intended mutation is a mutation that alters the splicing of a gene. In some embodiments, the intended mutation is a mutation that alters the regulatory sequence of a gene (e.g., a gene promotor or gene repressor). In some embodiments, any of the base editors provided herein are capable of generating a ratio of intended mutations to unintended mutations (e.g., intended mutations:unintended mutations) that is greater than 1:1. In some embodiments, any of the base editors provided herein are capable of generating a ratio of intended mutations to unintended mutations that is at least 1.5:1, at least 2:1, at least 2.5:1, at least 3:1, at least 3.5:1, at least 4:1, at least 4.5:1, at least 5:1, at least 5.5:1, at least 6:1, at least 6.5:1, at least 7:1, at least 7.5:1, at least 8:1, at least 10:1, at least 12:1, at least 15:1, at least 20:1, at least 25:1, at least 30:1, at least 40:1, at least 50:1, at least 100:1, at least 150:1, at least 200:1, at least 250:1, at least 500:1, or at least 1000:1, or more. It should be appreciated that the characteristics of the base editors described herein may be applied to any of the fusion proteins or complexes, or methods of using the fusion proteins or complexes provided herein.
Base editing is often referred to as a “modification”, such as, a genetic modification, a gene modification and modification of the nucleic acid sequence and is clearly understandable based on the context that the modification is a base editing modification. A base editing modification is therefore a modification at the nucleotide base level, for example as a result of the deaminase activity discussed throughout the disclosure, which then results in a change in the gene sequence, and may affect the gene product. In essence therefore, the gene editing modification described herein may result in a modification of the gene, structurally and/or functionally, wherein the expression of the gene product may be modified, for example, the expression of the gene is knocked out; or conversely, enhanced, or, in some circumstances, the gene function or activity may be modified. Using the methods disclosed herein, a base editing efficiency may be determined as the knockdown efficiency of the gene in which the base editing is performed, wherein the base editing is intended to knockdown the expression of the gene. A knockdown level may be validated quantitatively by determining the expression level by any detection assay, such as assay for protein expression level, for example, by flow cytometry; assay for detecting RNA expression such as quantitative RT-PCR, northern blot analysis, or any other suitable assay such as pyrosequencing; and may be validated qualitatively by nucleotide sequencing reactions.
In some embodiments, the modification, e.g., single base edit results in about or at least about a 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% reduction, or reduction to an undetectable level, of the gene targeted expression.
In some embodiments, any of the base editor systems provided herein result in less than 50%, 40%, 30%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, or 0.01% indel formation in the target polynucleotide sequence.
In some embodiments, targeted modifications, e.g., single base editing, are used simultaneously or sequentially to target at least 4, 5, 6, 7, 8, 9, 10, 11, 12 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50 different endogenous sequences for base editing with different guide RNAs.
Some aspects of the disclosure are based on the recognition that any of the base editors provided herein are capable of efficiently generating an intended mutation, such as a point mutation, in a nucleic acid (e.g., a nucleic acid within a genome of a subject) without generating a significant number of unintended mutations, such as unintended point mutations (i.e., mutation of bystanders). In some embodiments, any of the base editors provided herein are capable of generating at least 0.01% of intended mutations (i.e., at least 0.01% base editing efficiency). In some embodiments, any of the base editors provided herein are capable of generating at least 0.01%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, 95%, or 99% of intended mutations.
The invention provides adenosine deaminase variants (e.g., ABE8 variants) that have increased efficiency and specificity. In particular, the adenosine deaminase variants described herein are more likely to edit a desired base within a polynucleotide, and are less likely to edit bases that are not intended to be altered (e.g., “bystanders”).
In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced bystander editing or mutations. In some embodiments, an unintended editing or mutation is a bystander mutation or bystander editing, for example, base editing of a target base (e.g., A or C) in an unintended or non-target position in a target window of a target nucleotide sequence. In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced bystander editing or mutations compared to a base editor system comprising an ABE7 base editor, e.g., ABE7.10. In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced bystander editing or mutations by at least 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% compared to a base editor system comprising an ABE7 base editor, e.g., ABE7.10. In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced bystander editing or mutations by at least 1.1 fold, at least 1.2 fold, at least 1.3 fold, at least 1.4 fold, at least 1.5 fold, at least 1.6 fold, at least 1.7 fold, at least 1.8 fold, at least 1.9 fold, at least 2.0 fold, at least 2.1 fold, at least 2.2 fold, at least 2.3 fold, at least 2.4 fold, at least 2.5 fold, at least 2.6 fold, at least 2.7 fold, at least 2.8 fold, at least 2.9 fold, or at least 3.0 fold compared to a base editor system comprising an ABE7 base editor, e.g., ABE7.10.
In some embodiments, any of the base editor systems provided herein result in less than 70%, 65%, 60%, 55%, 50%, 40%, 30%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, or 0.01% bystander editing of one or more nucleotides (e.g., an off-target nucleotide). In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced spurious editing. In some embodiments, an unintended editing or mutation is a spurious mutation or spurious editing, for example, non-specific editing or guide independent editing of a target base (e.g., A or C) in an unintended or non-target region of the genome. In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced spurious editing compared to a base editor system comprising an ABE7 base editor, e.g., ABE7 10. In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced spurious editing by at least 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% compared to a base editor system comprising an ABE7 base editor, e.g., ABE7.10. In some embodiments, any of the base editing system comprising one of the ABE8 base editor variants described herein has reduced spurious editing by at least 1.1 fold, 1.2 fold, 1.3 fold, 1.4 fold, 1.5 fold, 1.6 fold, 1.7 fold, 1.8 fold, 1.9 fold, 2.0 fold, 2.1 fold, 2.2 fold, 2.3 fold, 2.4 fold, 2.5 fold, 2.6 fold, 2.7 fold, 2.8 fold, 2.9 fold, or 3.0 fold compared to a base editor system comprising an ABE7 base editor, e.g., ABE7.10.
In some embodiments, any of the ABE8 base editor variants described herein have at least 0.01%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% total or target base editing efficiency.
In some embodiments, any of the ABE8 base editor variants described herein has higher base editing efficiency compared to the ABE7 base editors. In some embodiments, any of the ABE8 base editor variants described herein have at least 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, 150%, 155%, 160%, 165%, 170%, 175%, 180%, 185%, 190%, 195%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300%, 310%, 320%, 330%, 340%, 350%, 360%, 370%, 380%, 390%, 400%, 450%, or 500% higher base editing efficiency compared to an ABE7 base editor, e.g., ABE7.10.
The ABE8 base editor variants described herein may be delivered to a host cell via a viral particle (e.g., a RABV particle), a plasmid, a vector, a LNP complex, or an mRNA. In some embodiments, any of the ABE8 base editor variants described herein is delivered to a host cell via a pseudotyped recombinant rabies virus (RABV) particle comprising a chimeric envelope protein.
In some embodiments, the method described herein, for example, the base editing methods has minimum to no off-target effects. In some embodiments, the method described herein, for example, the base editing methods, has minimal to no chromosomal translocations.
In some embodiments, the base editing method described herein results in about 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% of a cell population that have been successfully edited.
In some embodiments, the percent of viable cells in a cell population following a base editing intervention is greater than at least 60%, 70%, 80%, or 90% of the starting cell population at the time of the base editing event. In some embodiments, the percent of viable cells in a cell population following editing is about 70%. In some embodiments, the percent of viable cells in a cell population following editing is about 75%. In some embodiments, the percent of viable cells in a cell population following editing is about 80%. In some embodiments, the percent of viable cells in a cell population as described above is about 85%. In some embodiments, the percent of viable cells in a cell population as described above is about 90%, or about 91%, 92%, 93%, 94% 95%, 96%, 97%, 98%, 99%, or 100% of the cells in the population at the time of the base editing event. In some embodiments the engineered cell population can be further expanded in vitro by about 2 fold, about 3-fold, about 4-fold, about 5-fold, about 6-fold, about 7-fold, about 8-fold, about 9-fold, about 10-fold, about 15-fold, about 20-fold, about 25-fold, about 30-fold, about 35-fold, about 40-fold, about 45-fold, about 50-fold, or about 100-fold.
In embodiments, the cell population is a population of cells contacted with a base editor, complex, or base editor system of the present disclosure.
The number of intended mutations and indels can be determined using any suitable method, for example, as described in International PCT Application Nos. PCT/US2017/045381 (WO2018/027078) and PCT/US2016/058344 (WO2017/070632); Komor, A. C., et al., “Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage” Nature 533, 420-424 (2016); Gaudelli, N. M., et al., “Programmable base editing of A·T to G·C in genomic DNA without DNA cleavage” Nature 551, 464-471 (2017); and Komor, A. C., et al., “Improved base excision repair inhibition and bacteriophage Mu Gam protein yields C:G-to-T:A base editors with higher efficiency and product purity” Science Advances 3:eaao4774 (2017); the entire contents of which are hereby incorporated by reference.
In some embodiments, to calculate indel frequencies, sequencing reads are scanned for exact matches to two 10-bp sequences that flank both sides of a window in which indels can occur. If no exact matches are located, the read is excluded from analysis. If the length of this indel window exactly matches the reference sequence the read is classified as not containing an indel. If the indel window is two or more bases longer or shorter than the reference sequence, then the sequencing read is classified as an insertion or deletion, respectively. In some embodiments, the base editors provided herein can limit formation of indels in a region of a nucleic acid. In some embodiments, the region is at a nucleotide targeted by a base editor or a region within 2, 3, 4, 5, 6, 7, 8, 9, or 10 nucleotides of a nucleotide targeted by a base editor.
Details of base editor efficiency are described in International PCT Application Nos. PCT/US2017/045381 (WO 2018/027078) and PCT/US2016/058344 (WO 2017/070632), each of which is incorporated herein by reference for its entirety. Also see Komor, A. C., et al., “Programmable editing of a target base in genomic DNA without double-stranded DNA cleavage” Nature 533, 420-424 (2016); Gaudelli, N. M., et al., “Programmable base editing of A·T to G·C in genomic DNA without DNA cleavage” Nature 551, 464-471 (2017); and Komor, A. C., et al., “Improved base excision repair inhibition and bacteriophage Mu Gam protein yields C:G-to-T:A base editors with higher efficiency and product purity” Science Advances 3:eaao4774 (2017), the entire contents of which are hereby incorporated by reference. In some embodiments, editing of a plurality of nucleobase pairs in one or more genes using the methods provided herein results in formation of at least one intended mutation. In some embodiments, said formation of said at least one intended mutation results in the disruption the normal function of a gene. In some embodiments, said formation of said at least one intended mutation results decreases or eliminates the expression of a protein encoded by a gene.
In some embodiments, the base editor system provided herein is capable of multiplex editing of a plurality of nucleobase pairs in one or more genes or polynucleotide sequences. In some embodiments, the plurality of nucleobase pairs is located in the same gene or in one or more genes, wherein at least one gene is located in a different locus. In some embodiments, the multiplex editing comprises one or more guide polynucleotides. In some embodiments, the multiplex editing comprises one or more base editor systems. In some embodiments, the multiplex editing comprises one or more base editor systems with a single guide polynucleotide or a plurality of guide polynucleotides. In some embodiments, the multiplex editing comprises one or more guide polynucleotides with a single base editor system. It should be appreciated that the characteristics of the multiplex editing using any of the base editors as described herein can be applied to any combination of methods using any base editor provided herein. It should also be appreciated that the multiplex editing using any of the base editors as described herein can comprise a sequential editing of a plurality of nucleobase pairs.
In some embodiments, the plurality of nucleobase pairs are in one more genes. In some embodiments, the plurality of nucleobase pairs is in the same gene. In some embodiments, at least one gene in the one more genes is located in a different locus.
In some embodiments, the editing is editing of the plurality of nucleobase pairs in at least one protein coding region, in at least one protein non-coding region, or in at least one protein coding region and at least one protein non-coding region.
In some embodiments, the editing is in conjunction with one or more guide polynucleotides. In some embodiments, the base editor system comprises one or more base editor systems. In some embodiments, the base editor system comprises one or more base editor systems in conjunction with a single guide polynucleotide or a plurality of guide polynucleotides. In some embodiments, the editing is in conjunction with one or more guide polynucleotide with a single base editor system. In some embodiments, the editing is in conjunction with at least one guide polynucleotide that does not require a PAM sequence to target binding to a target polynucleotide sequence or with at least one guide polynucleotide that requires a PAM sequence to target binding to a target polynucleotide sequence, or with a mix of at least one guide polynucleotide that does not require a PAM sequence to target binding to a target polynucleotide sequence and at least one guide polynucleotide that does require a PAM sequence to target binding to a target polynucleotide sequence. It should be appreciated that the characteristics of the multiplex editing using any of the base editors as described herein can be applied to any of combination of the methods of using any of the base editors provided herein. It should also be appreciated that the editing can comprise a sequential editing of a plurality of nucleobase pairs.
In some embodiments, the base editor system capable of multiplex editing of a plurality of nucleobase pairs in one or more genes comprises one of ABE7, ABE8, and/or ABE9 base editors. In some embodiments, the base editor system capable of multiplex editing comprising one of the ABE8 base editor variants described herein has higher multiplex editing efficiency compared to the base editor system capable of multiplex editing comprising one of ABE7 base editors. In some embodiments, use of a base editor system capable of multiplex editing of a plurality of nucleobase pairs in one or more genes described herein does not comprise a risk or occurrence of chromosomal translocations.
Fusion proteins or complexes of the invention comprising an adenosine deaminase variant may be expressed in virtually any host cell of interest, including but not limited to bacteria, yeast, fungi, insects, plants, and animal cells using routine methods known to the skilled artisan. For example, a DNA encoding an adenosine deaminase of the invention can be cloned by designing suitable primers for the upstream and downstream of CDS based on the cDNA sequence. The cloned DNA may be directly, or after digestion with a restriction enzyme when desired, or after addition of a suitable linker and/or a nuclear localization signal, ligated with a DNA encoding one or more additional components of a base editing system. The base editing system is translated in a host cell to form a complex.
A polynucleotide encoding a polypeptide described herein can be obtained by chemically synthesizing the polynucleotide, or by connecting synthesized partly overlapping oligo short chains by utilizing the PCR method and the Gibson Assembly method to construct a polynucleotide (e.g., DNA) encoding the full length thereof. The advantage of constructing a full-length polynucleotide by chemical synthesis or a combination of PCR method or Gibson Assembly method is that the codons to be used can be selected in according to the host into which the polynucleotide is to be introduced. In the expression from a heterologous DNA molecule, the protein expression level is expected to increase by converting the DNA sequence thereof to a codon highly frequently used in the host organism. Codon use data for a host cell (e.g., codon use data available at kazusa.or.jp/codon/index.html) can be used to guide codon optimization for a polynucleotide sequence encoding a polypeptide. Codons having low use frequency in the host may be converted to a codon coding the same amino acid and having high use frequency.
An expression vector containing a polynucleotide encoding a nucleic acid sequence-recognizing module and/or a nucleic acid base converting enzyme can be produced, for example, by linking the DNA to the downstream of a promoter in a suitable expression vector.
As the expression vector, Escherichia coli-derived plasmids (e.g., pBR322, pBR325, pUC12, pUC13); Bacillus subtilis-derived plasmids (e.g., pUB110, pTP5, pC194); yeast-derived plasmids (e.g., pSH19, pSH15); insect cell expression plasmids (e.g., pFast-Bac); animal cell expression plasmids (e.g., pA1-11, pXT1, pRc/CMV, pRc/RSV, pcDNAI/Neo); bacteriophages such as .lambda phage and the like; insect virus vectors such as baculovirus and the like (e.g., BmNPV, AcNPV); animal virus vectors such as retrovirus, vaccinia virus, adenovirus and the like, and the like are used.
Regarding the promoter to be used, any promoter appropriate for a host to be used for gene expression can be used. In a conventional method using double-stranded breaks, since the survival rate of the host cell sometimes decreases markedly due to the toxicity, it is desirable to increase the number of cells by the start of the induction by using an inductive promoter. However, since sufficient cell proliferation can also be afforded by expressing the nucleic acid-modifying enzyme complex of the present invention, a constitutive promoter can be used without limitation.
For example, when the host is an animal cell, an SR.alpha. promoter, SV40 promoter, LTR promoter, cytomegalovirus (CMV) promoter, Rous sarcoma virus (RSV) promoter, Moloney mouse leukemia virus (MoMuLV), LTR, herpes simplex virus thymidine kinase (HSV-TK) promoter, and the like can be used. Of these, CMV promoter, SR.alpha. promoter and the like are preferable.
When the host is Escherichia coli, a trp promoter, lac promoter, recA promoter, .lamda.P.sub.L promoter, lpp promoter, T7 promoter, and the like can be used.
When the host is in the genus Bacillus, the SPO1 promoter, SPO2 promoter, penP promoter, and the like can be used.
When the host is a yeast, the Gal1/10 promoter, PHO5 promoter, PGK promoter, GAP promoter, ADH promoter, and the like can be used.
When the host is an insect cell, the polyhedrin promoter, P10 promoter, and the like can be used.
When the host is a plant cell, the CaMV35S promoter, CaMV19S promoter, NOS promoter, and the like can be used.
Expression vectors for use in the present invention, besides those mentioned above, can comprise an enhancer, a splicing signal, a terminator, a polyA addition signal, a selection marker such as drug resistance gene, an auxotrophic complementary gene and the like, a replication origin, and the like can be used.
An RNA encoding a protein domain described herein can be prepared by, for example, in vitro transcription of a nucleic acid sequence encoding any of the fusion proteins or complexes disclosed herein.
A fusion protein or complex of the invention can be intracellularly expressed by introducing into the cell an expression vector comprising a nucleic acid sequence encoding the fusion protein or complex.
Host cells of interest, include but are not limited to bacteria, yeast, fungi, insects, plants, and animal cells. For example, a host cell may comprise bacteria from the genus Escherichia, such as Escherichia coli K12.cndot.DH1 [Proc. Natl. Acad. Sci. USA, 60, 160 (1968)], Escherichia coli JM103 [Nucleic Acids Research, 9, 309 (1981)], Escherichia coli JA221 [Journal of Molecular Biology, 120, 517 (1978)], Escherichia coli HB101 [Journal of Molecular Biology, 41, 459 (1969)], Escherichia coli C600 [Genetics, 39, 440 (1954)] and the like.
A host cell may comprise bacteria from the genus Bacillus, for example Bacillus subtilis M1114 [Gene, 24, 255 (1983)], Bacillus subtilis 207-21 [Journal of Biochemistry, 95, 87 (1984)] and the like.
A host cell may be a yeast cell. Examples of yeast cells include Saccharomyces cerevisiae AH22, AH22R.sup.-, NA87-1l A, DKD-5D, 20B-12, Schizosaccharomyces pombe NCYC1913, NCYC2036, Pichia pastoris KM71 and the like.
When the viral delivery methods utilize the virus AcNPV, cells from a cabbage armyworm larva-derived established line (Spodoptera frugiperda cell; Sf cell), MG1 cells derived from the mid-intestine of Trichoplusia ni, High Fiver™ cells derived from an ovary of Trichoplusia ni, Mamestra brassicae-derived cells, Estigmena acrea-derived cells and the like can be used. When the virus is BmNPV, cells of Bombyx mori-derived established line (Bombyx mori N cell; BmN cell) and the like are used. As the Sf cell, for example, Sf9 cell (ATCC CRL1711), Sf21 cell [all above, In Vivo, 13, 213-217 (1977)] and the like are used.
An insect can be any insect, for example, larva of Bombyx mori, Drosophila, cricket, and the like [Nature, 315, 592 (1985)].
Animal cells contemplated in the present invention include, but are not limited to, cell lines such as monkey COS-7 cells, monkey Vero cells, Chinese hamster ovary (CHO) cells, dhfr gene-deficient CHO cells, mouse L cells, mouse AtT-20 cells, mouse myeloma cells, rat GH3 cells, human FL cells and the like, pluripotent stem cells such as iPS cells, ES cells derived humans and other mammals, and primary cultured cells prepared from various tissues. Furthermore, zebrafish embryo, Xenopus oocyte, and the like can also be used.
Plant cells are also contemplated in the present invention. Plant cells include, but are not limited to, suspended cultured cells, callus, protoplast, leaf segment, root segment and the like prepared from various plants (e.g., grain such as rice, wheat, corn, and the like; product crops such as tomato, cucumber, eggplant and the like; garden plants such as carnations, Eustoma russellianum, and the like; and other plants such as tobacco, Arabidopsis thaliana and the like) are used.
All the above-mentioned host cells may be haploid (monoploid), or polyploid (e.g., diploid, triploid, tetraploid, etc.). Using conventional methods, mutations, in principle, introduced into only one homologous chromosome produce a heterogenous cell. Therefore, the desired phenotype is not expressed unless the mutation is dominant. For recessive mutations, acquiring a homozygous cell can be inconvenient due to labor and time requirements. In contrast, according to the present invention, since a mutation can be introduced into any allele on the homologous chromosome in the genome, the desired phenotype can be expressed in a single generation even in the case of recessive mutation, thereby solving the problem associated with conventional mutagenesis methods.
An expression vector can be introduced by a known method (e.g., the lysozyme method, the competent method, the PEG method, the CaCl2 coprecipitation method, electroporation, microinjection, particle gun method, lipofection, Agrobacterium-mediated delivery, etc.) according to the kind of the host.
Escherichia coli can be transformed according to the methods described in, for example, Proc. Natl. Acad. Sci. USA, 69, 2110 (1972), Gene, 17, 107 (1982).
The genus Bacillus can be introduced into a vector according to the methods described in, for example, Molecular & General Genetics, 168, 111 (1979).
A yeast can be introduced into a vector according to the methods described in, for example, Methods in Enzymology, 194, 182-187 (1991), Proc. Natl. Acad. Sci. USA, 75, 1929 (1978).
An insect cell and an insect can be introduced into a vector according to the methods described in, for example, Bio/Technology, 6, 47-55 (1988).
A vector can be introduced into an animal cell according to the methods described in, for example, Cell Engineering additional volume 8, New Cell Engineering Experiment Protocol, 263-267 (1995) (published by Shujunsha), and Virology, 52, 456 (1973).
A cell comprising a vector can be cultured according to a known method according to the kind of the host. For example, when Escherichia coli or genus Bacillus is cultured, a liquid medium is preferable as a medium to be used for the culture. The medium preferably contains a carbon source, nitrogen source, inorganic substance and the like necessary for the growth of the transformant. Examples of the carbon source include glucose, dextrin, soluble starch, sucrose and the like; examples of the nitrogen source include inorganic or organic substances such as ammonium salts, nitrate salts, corn steep liquor, peptone, casein, meat extract, soybean cake, potato extract and the like; and examples of the inorganic substance include calcium chloride, sodium dihydrogen phosphate, magnesium chloride and the like. The medium may contain yeast extract, vitamins, growth promoting factor and the like. The pH of the medium is preferably about 5 about 8.
As a medium for culturing Escherichia coli, for example, M9 medium containing glucose, casamino acid [Journal of Experiments in Molecular Genetics, 431-433, Cold Spring Harbor Laboratory, New York 1972] is preferable. Where necessary, for example, agents such as 3β-indolylacrylic acid may be added to the medium to ensure an efficient function of a promoter. Escherichia coli is cultured at generally about 15 to about 43° C. Where necessary, aeration and stirring may be performed.
The genus Bacillus is cultured at generally about 30 to about 40° C. Where necessary, aeration and stirring may be performed.
Examples of the medium for culturing yeast include Burkholder minimum medium [Proc. Natl. Acad. Sci. USA, 77, 4505 (1980)], SD medium containing 0.5% casamino acid [Proc. Natl. Acad. Sci. USA, 81, 5330 (1984)] and the like. The pH of the medium is preferably about 5 to about 8. The culture is performed at generally about 20° C. to about 35° C. Where necessary, aeration and stirring may be performed.
As a medium for culturing an insect cell or insect, for example, Grace's Insect Medium [Nature, 195, 788 (1962)] containing an additive such as inactivated 10% bovine serum and the like as appropriate and the like are used. The pH of the medium is preferably about 6.2 to about 6.4. The culture is performed at generally about 27° C. Where necessary, aeration and stirring may be performed.
As a medium for culturing an animal cell, for example, minimum essential medium (MEM) containing about 5 to about 20% of fetal bovine serum [Science, 122, 501 (1952)], Dulbecco's modified Eagle medium (DMEM) [Virology, 8, 396 (1959)], RPMI 1640 medium [The Journal of the American Medical Association, 199, 519 (1967)], 199 medium [Proceeding of the Society for the Biological Medicine, 73, 1 (1950)] and the like are used. The pH of the medium is preferably about 6 to about 8. The culture is performed at generally about 30° C. to about 40° C. Where necessary, aeration and stirring may be performed.
As a medium for culturing a plant cell, for example, MS medium, LS medium, B5 medium and the like are used. The pH of the medium is preferably about 5-about 8. The culture is performed at generally about 20° C. to about 30° C. Where necessary, aeration and stirring may be performed.
When a higher eukaryotic cell, such as animal cell, insect cell, plant cell and the like is used as a host cell, a polynucleotide encoding a base editing system of the present invention (e.g., comprising an adenosine deaminase variant) is introduced into a host cell under the regulation of an inducible promoter (e.g., metallothionein promoter (induced by heavy metal ion), heat shock protein promoter (induced by heat shock), Tet-ON/Tet-OFF system promoter (induced by addition or removal of tetracycline or a derivative thereof), steroid-responsive promoter (induced by steroid hormone or a derivative thereof) etc.), the induction substance is added to the medium (or removed from the medium) at an appropriate stage to induce expression of the nucleic acid-modifying enzyme complex, culture is performed for a given period to carry out a base editing and, introduction of a mutation into a target gene, transient expression of the base editing system can be realized.
Prokaryotic cells such as Escherichia coli and the like can utilize an inducible promoter. Examples of the inducible promoter include, but are not limited to, lac promoter (induced by IPTG), cspA promoter (induced by cold shock), araBAD promoter (induced by arabinose) and the like.
Alternatively, the above-mentioned inductive promoter can also be utilized as a vector removal mechanism when higher eukaryotic cells, such as animal cell, insect cell, plant cell and the like are used as a host cell. That is, a vector is mounted with a replication origin that functions in a host cell, and a nucleic acid encoding a protein necessary for replication (e.g., SV40 on and large T antigen, oriP and EBNA-1 etc. for animal cells), of the expression of the nucleic acid encoding the protein is regulated by the above-mentioned inducible promoter. As a result, while the vector is autonomously replicable in the presence of an induction substance, when the induction substance is removed, autonomous replication is not available, and the vector naturally falls off along with cell division (autonomous replication is not possible by the addition of tetracycline and doxycycline in Tet-OFF system vector).
The suitability of nucleobase editors to target one or more nucleotides in a polynucleotide sequence (e.g., a gene) is evaluated as described herein. In one embodiment, a subject is administered the pseudotyped recombinant rabies virus (RABV) particle of the disclosure. In one embodiment, a single cell of interest is transfected, transduced, or otherwise modified with a nucleic acid molecule or molecules encoding a base editing system described herein together with a small amount of a vector encoding a reporter (e.g., GFP). These cells can be any cell line known in the art. Alternatively, primary cells (e.g., human) may be used. Cells may also be obtained from a subject or individual, such as from tissue biopsy, surgery, blood, plasma, serum, or other biological fluid. Such cells may be relevant to the eventual cell target.
Delivery may be performed using the pseudotyped recombinant rabies virus (RABV) particle of the disclosure. In other embodiments, transfection may be performed using lipid transfection (such as Lipofectamine or Fugene) or by electroporation. Transfection may be performed using lipid nanoparticles (LNPs). Following transfection, expression of a reporter (e.g., GFP) can be determined either by fluorescence microscopy or by flow cytometry to confirm consistent and high levels of transfection. These preliminary transfections can comprise different nucleobase editors to determine which combinations of editors give the greatest activity. The system can comprise one or more different vectors. In one embodiment, the base editor is codon optimized for expression of the desired cell type, preferentially a eukaryotic cell, preferably a mammalian cell or a human cell.
The activity of the nucleobase editor is assessed as described herein, i.e., by sequencing the genome of the cells to detect alterations in a target sequence. For Sanger sequencing, purified PCR amplicons are cloned into a plasmid backbone, transformed, miniprepped and sequenced with a single primer. Sequencing may also be performed using next generation sequencing (NGS) techniques. When using next generation sequencing, amplicons may be 300-500 bp with the intended cut site placed asymmetrically. Following PCR, next generation sequencing adapters and barcodes (for example Illumina multiplex adapters and indexes) may be added to the ends of the amplicon, e.g., for use in high throughput sequencing (for example on an Illumina MiSeq). The fusion proteins or complexes that induce the greatest levels of target specific alterations in initial tests can be selected for further evaluation.
In particular embodiments, the nucleobase editors are used to target polynucleotides of interest. In one embodiment, a nucleobase editor of the invention is delivered to cells (e.g., neurons or occular cells) in conjunction with one or more guide RNAs that are used to target one or more nucleic acid sequences of interest within the genome of a cell, thereby altering the target gene(s). In some embodiments, a base editor is targeted by one or more guide RNAs to introduce one or more edits to the sequence of one or more genes of interest. In some embodiments, the one or more edits to the sequence of one or more genes of interest decrease or eliminate expression of the protein encoded by the gene in the host cell. In some embodiments, expression of one or more proteins encoded by one or more genes of interest is completely knocked out or eliminated in the host cell.
In some embodiments, the host cell is selected from a bacterial cell, plant cell, insect cell, human cell, or mammalian cell. In some embodiments, the host cell is a mammalian cell. In some embodiments, the host cell is a human cell. In some embodiments, the cell is in vitro. In some embodiments, the cell is in vivo.
Provided herein are compositions (e.g., pharmaceutical compositions) comprising any of the recombinant rabies virus genomes and recombinant rabies viruses described herein. The term “pharmaceutical composition,” as used herein, refers to a composition formulated for pharmaceutical use. In certain embodiments, the pharmaceutical composition further comprises a pharmaceutically acceptable carrier. In certain embodiments, the pharmaceutical composition comprises additional agents (e.g., for specific delivery, increasing half-life, or other therapeutic compounds).
As used herein, the term “pharmaceutically-acceptable carrier” refers to a pharmaceutically-acceptable material, composition, or vehicle, such as a liquid or solid filler, diluent, excipient, manufacturing aid (e.g., lubricant, talc magnesium, calcium or zinc stearate, or steric acid), or solvent encapsulating material, involved in carrying or transporting the compound (e.g., a recombinant RABV genome or recombinant RABV described herein) from one site (e.g., the delivery site) of the body, to another site (e.g., a target organ, tissue, or portion of the body). A pharmaceutically acceptable carrier is “acceptable” in the sense of being compatible with the other ingredients of the formulation and not injurious to the tissue of the subject (e.g., physiologically compatible, sterile, physiologic pH, etc.).
Some nonlimiting examples of materials which can serve as pharmaceutically-acceptable carriers include: (1) sugars, such as lactose, glucose and sucrose; (2) starches, such as com starch and potato starch; (3) cellulose, and its derivatives, such as sodium carboxymethyl cellulose, methylcellulose, ethyl cellulose, microcrystalline cellulose and cellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7) lubricating agents, such as magnesium stearate, sodium lauryl sulfate and talc; (8) excipients, such as cocoa butter and suppository waxes; (9) oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, com oil and soybean oil; (10) glycols, such as propylene glycol; (11) polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol (PEG); (12) esters, such as ethyl oleate and ethyl laurate; (13) agar; (14) buffering agents, such as magnesium hydroxide and aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer's solution; (19) ethyl alcohol; (20) pH buffered solutions; (21) polyesters, polycarbonates and/or polyanhydrides; (22) bulking agents, such as polypeptides and amino acids (23) serum alcohols, such as ethanol; and (23) other non-toxic compatible substances employed in pharmaceutical formulations. Wetting agents, coloring agents, release agents, coating agents, sweetening agents, flavoring agents, perfuming agents, preservative and antioxidants can also be present in the formulation. The terms such as “excipient,” “carrier,” “pharmaceutically acceptable carrier,” “vehicle,” or the like are used interchangeably herein.
Pharmaceutical compositions can comprise one or more pH buffering compounds to maintain the pH of the formulation at a predetermined level that reflects physiological pH, such as in the range of about 5.0 to about 8.0. The pH buffering compound used in the aqueous liquid formulation can be an amino acid, such as histidine, or a mixture of amino acids, such as histidine and glycine. Alternatively, the pH buffering compound is preferably an agent which maintains the pH of the formulation at a predetermined level, such as in the range of about 5.0 to about 8.0, and which does not chelate calcium ions. Illustrative examples of such pH buffering compounds include, but are not limited to, imidazole and acetate ions. The pH buffering compound may be present in any amount suitable to maintain the pH of the formulation at a predetermined level.
Pharmaceutical compositions can also contain one or more osmotic modulating agents, i.e., a compound that modulates the osmotic properties (e.g., tonicity, osmolality, and/or osmotic pressure) of the formulation to a level that is acceptable to the blood stream and blood cells of recipient individuals. The osmotic modulating agent can be an agent that does not chelate calcium ions. The osmotic modulating agent can be any compound known or available to those skilled in the art that modulates the osmotic properties of the formulation. One skilled in the art may empirically determine the suitability of a given osmotic modulating agent for use in the inventive formulation. Illustrative examples of suitable types of osmotic modulating agents include, but are not limited to: salts, such as sodium chloride and sodium acetate; sugars, such as sucrose, dextrose, and mannitol; amino acids, such as glycine; and mixtures of one or more of these agents and/or types of agents. The osmotic modulating agent(s) may be present in any concentration sufficient to modulate the osmotic properties of the formulation.
In certain embodiments, the pharmaceutical composition is formulated for delivery to a subject, e.g., for gene therapy. Suitable routes of administrating the pharmaceutical composition described herein include, without limitation: topical, subcutaneous, transdermal, intradermal, intralesional, intraarticular, intraperitoneal, intravesical, transmucosal, gingival, intradental, intracochlear, transtympanic, intraorgan, epidural, intrathecal, intramuscular, intravenous, intravascular, intraosseus, periocular, intratumoral, intracerebral, and intracerebroventricular administration.
In certain embodiments, the pharmaceutical composition described herein is administered locally to a diseased site (e.g., tumor site). In certain embodiments, the pharmaceutical composition described herein is administered to a subject by injection, by means of a catheter, by means of a suppository, or by means of an implant, the implant being of a porous, non-porous, or gelatinous material, including a membrane, such as a silastic membrane, or a fiber.
In certain embodiments, the pharmaceutical composition described herein is delivered in a controlled release system. In certain embodiments, a pump can be used (see, e.g., Langer, 1990, Science 249: 1527-1533; Sefton, 1989, CRC Crit. Ref. Biomed. Eng. 14:201; Buchwald et al, 1980, Surgery 88:507; Saudek et al., 1989, N. Engl. J. Med. 321:574). In certain embodiments, polymeric materials can be used. See, e.g., Medical Applications of Controlled Release (Langer and Wise eds., CRC Press, Boca Raton, Fla., 1974); Controlled Drug Bioavailability, Drug Product Design and Performance (Smolen and Ball eds., Wiley, New York, 1984); Ranger and Peppas, 1983, Macromol. Sci. Rev. Macromol. Chem. 23:61. See, also, Levy et al, 1985, Science 228: 190; During et al, 1989, Ann. Neurol. 25:351; Howard et ah, 1989, J. Neurosurg. 71: 105. Other controlled release systems are discussed, for example, in Langer, supra.
In certain embodiments, the pharmaceutical composition is formulated in accordance with routine procedures as a composition adapted for intravenous or subcutaneous administration to a subject, e.g., a human. In certain embodiments, pharmaceutical compositions for administration by injection are solutions in sterile isotonic used as solubilizing agent and a local anesthetic such as lignocaine to ease pain at the site of the injection.
Generally, the ingredients are supplied either separately or mixed together in unit dosage form, for example, as a dry lyophilized powder or water free concentrate in a hermetically sealed container such as an ampoule or sachette indicating the quantity of active agent.
Where the pharmaceutical is to be administered by infusion, it can be dispensed with an infusion bottle containing sterile pharmaceutical grade water or saline. Where the pharmaceutical composition is administered by injection, an ampoule of sterile water for injection or saline can be provided so that the ingredients can be mixed prior to administration.
A pharmaceutical composition for systemic administration can be a liquid, e.g., sterile saline, lactated Ringer's or Hank's solution. In addition, the pharmaceutical composition can be in solid forms and re-dissolved or suspended immediately prior to use. Lyophilized forms are also contemplated. The pharmaceutical composition can be contained within a lipid particle or vesicle, such as a liposome or microcrystal, which is also suitable for parenteral administration. The particles can be of any suitable structure, such as unilamellar or plurilamellar, so long as compositions are contained therein. Compounds can be entrapped in “stabilized plasmid-lipid particles” (SPLP) containing the fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), low levels (5-10 mol %) of cationic lipid, and stabilized by a polyethyleneglycol (PEG) coating (see, e.g., Zhang Y. P. et al., Gene Ther. 1999, 6: 1438-47). Positively charged lipids such as 1,2-dioleoyl-3-trimethylammonium-propane, or “DOTAP,” are particularly preferred for such particles and vesicles. The preparation of such lipid particles is well known. See, e.g., U.S. Pat. Nos. 4,880,635; 4,906,477; 4,911,928; 4,917,951; 4,920,016; and 4,921,757; each of which is incorporated herein by reference.
The pharmaceutical composition described herein can be administered or packaged as a unit dose. The term “unit dose” when used in reference to a pharmaceutical composition of the present disclosure refers to physically discrete units suitable as unitary dosage for the subject, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required diluent; i.e., carrier, or vehicle.
Further, the pharmaceutical composition can be provided as a pharmaceutical kit comprising (a) a container containing a compound of the invention in lyophilized form and (b) a second container containing a pharmaceutically acceptable diluent (e.g., sterile, used for reconstitution or dilution of the lyophilized compound of the invention). Optionally associated with such containers) can be a notice in the form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, which notice reflects approval by the agency of manufacture, use or sale for human administration.
In another aspect, an article of manufacture containing materials useful for the treatment of the diseases described above is included. In certain embodiments, the article of manufacture comprises a container and a label. Suitable containers include, for example, bottles, vials, syringes, and test tubes. The containers can be formed from a variety of materials such as glass or plastic. In certain embodiments, the container holds a composition (e.g., a recombinant RABV genome or a recombinant RABV described herein) that is effective for treating a disease and can have a sterile access port. For example, the container can be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle. The active agent in the composition is a compound (e.g., a recombinant RABV genome or a recombinant RABV) of the disclosure. In certain embodiments, the label on or associated with the container indicates that the composition is used for treating the disease of choice. The article of manufacture can further comprise a second container comprising a pharmaceutically-acceptable buffer, such as phosphate-buffered saline, Ringer's solution, or dextrose solution. It can further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, syringes, and package inserts with instructions for use.
In some embodiments, any of the recombinant RABV genomes or recombinant RABV described herein are provided as part of a pharmaceutical composition. In some embodiments, the pharmaceutical composition comprises any of the recombinant RABV genomes or recombinant RABV described herein. In some embodiments, the pharmaceutical composition comprises any of the complexes provided herein.
In some embodiments, compositions provided herein are administered to a subject, for example, to a human subject, in order to affect a targeted genomic modification within the subject. In some embodiments, cells are obtained from the subject and contacted with any of the pharmaceutical compositions provided herein. In some embodiments, cells removed from a subject and contacted ex vivo with a pharmaceutical composition are re-introduced into the subject, optionally after the desired genomic modification has been affected or detected in the cells. Methods of delivering pharmaceutical compositions comprising nucleases are known, and are described, for example, in U.S. Pat. Nos. 6,453,242; 6,503,717; 6,534,261; 6,599,692; 6,607,882; 6,689,558: 6,824,978; 6,933,113; 6,979,539; 7,013,219; and 7,163,824, the disclosures of all of which are incorporated by reference herein in their entireties. Although the descriptions of pharmaceutical compositions provided herein are principally directed to pharmaceutical compositions which are suitable for administration to humans, it will be understood by the skilled artisan that such compositions are generally suitable for administration to animals or organisms of all sorts. Modification of pharmaceutical compositions suitable for administration to humans in order to render the compositions suitable for administration to various animals is well understood, and the ordinarily skilled veterinary pharmacologist can design and/or perform such modification with merely ordinary, if any, experimentation. Subjects to which administration of the pharmaceutical compositions is contemplated include, but are not limited to, humans and/or other primates; mammals, domesticated animals, pets, and commercially relevant mammals such as cattle, pigs, horses, sheep, cats, dogs, mice, and/or rats; and/or birds, including commercially relevant birds such as chickens, ducks, geese, and/or turkeys.
Formulations of the pharmaceutical compositions described herein may be prepared by any method known or hereafter developed in the art of pharmacology. In general, such preparatory methods include the step of bringing the active ingredient(s) into association with an excipient and/or one or more other accessory ingredients, and then, if necessary and/or desirable, shaping and/or packaging the product into a desired single- or multi-dose unit.
Pharmaceutical formulations may additionally comprise a pharmaceutically acceptable excipient, which, as used herein, includes any and all solvents, dispersion media, diluents, or other liquid vehicles, dispersion or suspension aids, surface active agents, isotonic agents, thickening or emulsifying agents, preservatives, solid binders, lubricants and the like, as suited to the particular dosage form desired. Remington's The Science and Practice of Pharmacy, 21st Edition, A. R. Gennaro (Lippincott, Williams & Wilkins, Baltimore, M D, 2006; incorporated in its entirety herein by reference) discloses various excipients used in formulating pharmaceutical compositions and known techniques for the preparation thereof. See also PCT application PCT/US2010/055131 (Publication number WO2011053982 A8, filed Nov. 2, 2010), incorporated in its entirety herein by reference, for additional suitable methods, reagents, excipients and solvents for producing pharmaceutical compositions comprising a nuclease. Except insofar as any conventional excipient medium is incompatible with a substance or its derivatives, such as by producing any undesirable biological effect or otherwise interacting in a deleterious manner with any other component(s) of the pharmaceutical composition, its use is contemplated to be within the scope of this disclosure. In certain embodiments, compositions in accordance with the present invention may be used for treatment of any of a variety of diseases, disorders, and/or conditions.
Various aspects of the present disclosure employs, unless otherwise indicated, conventional techniques of molecular biology (including recombinant techniques), microbiology, cell biology, biochemistry, and immunology, which are well within the purview of the skilled artisan. Such techniques are explained fully in the literature, such as, “Molecular Cloning: A Laboratory Manual”, second edition (Sambrook, 1989); “Oligonucleotide Synthesis” (Gait, 1984); “Animal Cell Culture” (Freshney, 1987); “Methods in Enzymology,” and “Handbook of Experimental Immunology” (Weir, 1996); “Gene Transfer Vectors for Mammalian Cells” (Miller and Calos, 1987); “Current Protocols in Molecular Biology” (Ausubel, 1987); “PCR: The Polymerase Chain Reaction”, (Mullis, 1994); “Current Protocols in Immunology” (Coligan, 1991). These techniques are applicable to the production of the various aspects of the present disclosure, and, as such, may be considered in making and practicing the same.
The methods of delivery and/or expressing a therapeutic transgene (e.g., a nucleobase editor comprising a polynucleotide programmable nucleotide binding domain and a nucleobase editing domain) find use in the treatment of a disease or disorder. In certain embodiments, a method of treating a disease or disorder in a subject comprises administering a pseudotyped recombinant RABV particle described herein, or a pharmaceutical composition described herein. In certain embodiments, the disease or disorder is a neurologic disease or disorder. In certain embodiments, the disease or disorder is a ophthalmic disease or disorder.
The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the assay, screening, and therapeutic methods of the invention, and are not intended to limit the scope of what the inventors regard as their invention.
The pseudotyped RABV particles with chimeric envelope proteins described herein employ a non-RABV envelope protein ectodomain and a non-RABV envelope protein transmembrane domain paired with the RABV envelope protein C terminal domain (CTD). Swapping in the RABV envelope protein CTD expands that list of compatible envelope proteins that a RABV particle may be pseudotyped with, thereby altering the tissue and cellular tropism of the RABV particle.
For the production of the pseudotyped RABV particles, non-rabies enveloped viruses and glycoprotein constructs were transfected into HEK293T cells infected with the parent RABV virus where the native glycoprotein gene is replaced with GFP (RABV ΔG-GFP) allowing the produced pseudotyped virus to be visualized. SAD B19 Rabies G was included in the set viruses tested as a positive control.
Progeny virus was then harvested and 32 μl of supernatant containing virus was added to fresh HEK293T cells. Three biological replicates were performed for pseudotyping with the chimeric glycoproteins. Overall, the presence of the rabies G CTD reproducibly enhanced the pseudotyping capacity of the glycoproteins tested, and multiple chimeric glycoproteins pseudotyped better than WT glycoproteins (
The RABV SAD B19 strain CTD employed is recited below. Additional RABV CTDs from other strains are also provided.
From the foregoing description, it will be apparent that variations and modifications may be made to the invention described herein to adopt it to various usages and conditions. Such embodiments are also within the scope of the following claims.
The recitation of a listing of elements in any definition of a variable herein includes definitions of that variable as any single element or combination (or subcombination) of listed elements. The recitation of an embodiment herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof.
All patents and publications mentioned in this specification are herein incorporated by reference to the same extent as if each independent patent and publication was specifically and individually indicated to be incorporated by reference.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/442,714, filed Feb. 1, 2023, the entire disclosure of which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63442714 | Feb 2023 | US |
