Patent Application
20140309145
The present invention relates to a method for the assembly and cloning of polynucleotides comprising highly similar polynucleotidic modules, that is highly versatile, does not require intermediate amplification step and can be easily automated for high throughput production of customized polynucleotidic modules.
Recent developments of methods for efficient gene targeting and site specific gene editing have unveiled exciting perspectives for gene therapies (Silva, Poirot et al. 2011). A key requirement of such methods is the ability to produce highly specific and active customized nuclease for unique genome target of interest. Since the past ten years, a lot of efforts have been made to develop customized nucleases with tailored DNA specificity (Carroll 2008; Silva, Poirot et al. 2011; Stoddard 2011; Urnov, Rebar et al. 2011). To date, the majority of customized nucleases used for genome editing are Meganucleases and Zinc finger nucleases. They have been successfully used in edition of numerous targets of interest (Silva, Poirot et al. 2011; Urnov, Rebar et al. 2011). Despite their great promise in the field of genome engineering, a more widespread adoption is still partly hampered by relatively long and/or costly engineering processes.
Engineering such molecule is not straightforward because of the strong context dependency affecting individual protein/base interaction patterns within the DNA binding interface of meganucleases (Grizot, Duclert et al.) and Zinc Finger Nucleases (Ramirez, Foley et al. 2008). Nevertheless, studies describing the making of tailored Zinc Finger proteins and Meganucleases with chosen specificities have been a major contribution to the field of protein engineering. In addition, the impact of these studies reaches far beyond the making of rare cutting endonucleases. Indeed, whereas Zinc Finger Nucleases result from the fusion of a Zinc Finger-based DNA binding domain with the catalytic domain of the bacterial FokI TypeIIS restriction enzyme (Kim, Cha et al. 1996; Smith, Berg et al. 1999; Smith, Bibikova et al. 2000), artificial Zinc Finger proteins have also been used in fusion with other effector domains: transcription activators or inhibitors have been tethered to Zinc Finger domains to activate or repress chosen genes (Choo, Sanchez-Garcia et al. 1994; Isalan, Klug et al. 2001; Pabo, Peisach et al. 2001), and fusions comprising recombinase (Gersbach, Gaj et al. 2010) or transposase domains (Feng, Bednarz et al. 2010) have also been described. With many meganucleases, and especially the meganucleases of the LAGLIDADG family (which have been the ones used in most genome engineering experiments), the catalytic core is embedded into the DNA binding domain (Stoddard 2005; Stoddard 2011). However, the catalytic activity can be inactivated with little impact on DNA binding (Chevalier, Sussman et al. 2004), and one can easily envision fusions between such catalytically inactive mutants and a new effector domain. Thus, developing faster processes to produce new DNA binding domains with chosen specificities (with a potential for automation and scale up) would benefit not only the potential users of rare cutting endonucleases, but also any application requiring to bring a chosen peptide next to a chosen DNA sequence in a living cell.
Transcription activator-like effectors (TALEs), a group of bacterial plant pathogen proteins have recently emerged as new engineerable scaffolds for the making of tailored DNA binding domains with chosen specificities (Boch, Scholze et al. 2009; Moscou and Bogdanove 2009; Boch and Bonas 2010; Christian, Cermak et al. 2010; Li, Huang et al. 2011; Li, Huang et al. 2011). TALE DNA binding domain is composed by a variable number of 33-35 aa repeat modules. These repeat modules are nearly identical to each other except for two variable amino acids located at positions 12 and 13 (Repeat Variable Di residues, RVD). The nature of residues 12 and 13 determines base preferences of individual repeat module. Moscou M. J and Bogdanove A. J and Boch et al. (Boch, Scholze et al. 2009; Moscou and Bogdanove 2009) described the preferential pairing between A, C, G, T and repeat modules harboring respectively NI, HD, NN, and NG at positions 12 and 13. This remarkable simple cipher, consisting in a one-repeat-to-one-base pair code, allowed for prediction of TAL effector binding site and more importantly for construction of custom TAL effector repeat domains that could be tailored to bind DNA sequence of interest. This unprecedented feature unmasked exciting perpectives to develop new molecular tools for targeted genome editing and required development of efficient assembly methods of TALE repeat modules. TALE-derived proteins have been used to specifically activate chosen genes (Morbitzer, Elsaesser et al. 2011; Zhang, Cong et al. 2011). In addition, TALE-based DNA binding domains can also be tethered to various effectors. TALENs (Transcription activator-like effector Nucleases) are formed by fusions of the cleavage domain of FokI and a TALE DNA binding domain (Christian, Cermak et al. 2010; Miller, Tan et al. 2010; Cermak, Doyle et al. 2011; Li, Huang et al. 2011; Li, Huang et al. 2011; Mahfouz, Li et al. 2011).
A major drawback for the large scale assembly of TALE DNA binding domains is that assembly of multiple highly similar repeats is challenging with classical molecular biology methods. In addition, chemical synthesis of such TALE DNA binding domain is prohibitive for large scale production. To tackle this issue, few different research groups have recently developed and reported assembly methods of TALE DNA binding domain (Miller, Tan et al. 2010; Cermak, Doyle et al. 2011; Geissler, Scholze et al. 2011; Li, Huang et al. 2011; Li, Huang et al. 2011; Morbitzer, Elsaesser et al. 2011; Weber, Engler et al. 2011; Zhang, Cong et al. 2011). Those methods all relied on the Golden gate cloning technology that is based on the ability of Type IIS restriction endonucleases to cleave outside of their recognition sequence and produce 4 bp 5′ overhang (Spear 2000; Engler, Kandzia et al. 2008). In these methods, TypeIIS recognition sites are placed at the 5′ and 3′ end of each DNA fragment in inverse orientation. This configuration allows for the seamless ligation of two DNA fragments that have compatible overhang sequences. In addition, as Type IIS restriction sites can be designed to have different overhang sequences, directional assembly of multiple DNA fragments is feasible. More importantly, as TypeIIS restriction sites are removed in the ligation process, restriction and ligation of multiple DNA fragments can be performed at the same time in a “one pot-one step reaction”, the hallmark of the Golden gate technology.
While these recently developed assembly methods are fast, inexpensive and clearly advantageous with respect to classical molecular biology techniques, their potential is limited when faced up with high throughput automated production of TALE DNA binding domains. Indeed, they all display different limitations. First, the “one pot-one step reaction” methods described so far are unable to efficiently assemble in one step, a functional DNA binding domains for TALE nuclease. Indeed, to assemble a TALE DNA binding domain, these methods requires mutiple pre-assemblies of TALE repeat subarrays. These TALE repeat subarrays are amplified either by PCR (Zhang, Cong et al. 2011) or by Ecoli transformation (Cermak, Doyle et al. 2011; Geissler, Scholze et al. 2011; Morbitzer, Elsaesser et al. 2011), then recovered and finally coupled together to form the functional TALE DNA binding domain. These amplification steps are prone to errors and/or hard to automate because they require numerous different steps such as plating, colony picking, PCR screening and DNA isolation. Second, the “one pot-one step reaction” leading to assembly of TALE repeats subarrays requires a large number of single repeat plasmid. Indeed, each of the four single TALE repeat (NI, HD, NN, NG and NK) has to be cloned into several flanking typeIIS cleavable sequences to allow for efficient directional assembly of multiple repeats at the same time. In addition, it also requires additional “receiver” plasmids for TALE repeat subarray subcloning, transformation and amplification. All together and depending on the method considered, a large number of plasmids have to be constructed to enable assembly of competent TALE DNA binding domains (Cermak, Doyle et al. 2011; Geissler, Scholze et al. 2011; Zhang, Cong et al. 2011). Third, the Golden Gate cloning plating efficiency (i.e the total amount of positive clones obtained after E. coli transformation and plating) decreases with increasing number of incorporated modules (Weber, Engler et al. 2011). Indeed, Weber & al reported that plating efficiency dramatically dropped from 30 000 to 150 positive colonies when the number of incorporated modules increased from 2 to 6 (Weber, Engler et al. 2011). This drawback hampers generation of high diversity libraries of TALE DNA binding domains.
Hence, to overcome the different drawbacks described above, we sought to develop a new method for assembly and cloning polynucleotides comprising highly similar polynucleotidic modules, such as TALE repeated modules. This assembly method is versatile, does not require intermediate amplification steps, and can be easily automated for high throughput production of customized polynucleotidic modules such as the repeated modules of TALE DNA binding domains. It consists in a sequential assembly of repeated modules on a solid phase supported by a 96 well plate format. In this method, a polynucleotide comprising the repeated module is linked to an organic moiety (biotin or digoxygenin) that binds specifically to the solid phase coated with streptavidin or digoxygenin-specific antibodies. Repeated modules are sequentially added via series of consecutive restriction and ligation steps using Type IIS restriction sites and enzymes. This new method displays several advantages with respect to the methods recently documented in the literature.
Anchoring a DNA fragment onto a solid phase allows for easy removal of excess reactants, byproducts and enzymes and thus theoretically increases the success rate of repeated modules recovery. This method doesn't require any intermediate amplification step such as E. coli transformation/DNA isolation (Cermak, Doyle et al. 2011; Geissler, Scholze et al. 2011; Morbitzer, Elsaesser et al. 2011) and PCR amplification of TALE repeated modules (Zhang, Cong et al. 2011) and it allows for assembly of flexible amounts of repeated modules. In addition, our method requires only one construction per repeat module and one “receiver plasmid”. Furthermore, this method can be used on a 96 well plate format and thus allows for simultaneous assembly of a large number of repeated modules. This feature makes it easy to automate with a 96 head pipetting robot.
Finally, this method has high success rates of products recovery and plating efficiency. The large number of positive colonies obtained could enable generation of high diversity libraries of polynucleotides repeated modules such as TALE DNA binding domains.
The present invention relates to a method for the assembly and cloning of polynucleotides comprising highly similar polynucleotidic modules, that is highly versatile, does not require intermediate amplification step and can be easily automated for high throughput production of customized polynucleotides comprising an array of multiple polynucleotidic modules. The method of the present invention comprises a sequential assembly of polynucleotidic modules on a solid phase. The method of the present invention is particularly well-suited for assembly of Transcription Activator-Like Effector (TALE) DNA binding repeat modules. The method of the present invention allows to produce libraries of polynucleotides comprising highly similar polynucleotidic modules such as TALE DNA binding domains.
In addition to the preceding features, the invention further comprises other features that will emerge from the description and appended drawings that follow. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following figures in conjunction with the detailed description below.
Binding sites BbvI, SfaNI and SfiI are indicated in red, cyan and green respectively. Overhangs generated by the three enzymes are displayed in dashed lines with the same color code.
For the sake of clarity, TALE repeat polynucleotidic modules used in the process are displayed with overhangs that are free and ready to react.
CAPT1.3 (SEQ ID NO: 1) and CAPT1.4 (SEQ ID NO: 2) targeted sequences and DNA spacer are displayed in green, cyan and red respectively.
Solid phase synthesis of TALE repeat stretch using sequential parallel process. For the sake of clarity, repeat polynucleotides modules used in the process are displayed with overhangs that are free and ready to react.
SADE2.3 target sequences (SEQ ID NO: 3) and DNA spacer are displayed in green and red respectively. The first biotinylated building blocks of TALE repeats left and right are displayed as “RVD_bx-biot”.
SADE2.3 target sequences (SEQ ID NO: 3) and DNA spacer are displayed in green and red respectively. The first biotinylated building block is marked as “RVD_b3-biot”.
AvrBS3 target sequence and DNA spacer are displayed in green and red respectively. The first biotinylated building block is displayed as “RVD_b2-biot”.
Workflow of steps 1-16 of the process.
Colony PCR screens results of a 14.5 TALE repeats polynucleotide assembly. * Correspond to clones containing 14.5 repeats polynucleotides.
Workflow of steps 1-16 of the reverse elongation process and steps 17-19 of sequential linear synthesis.
The above objects highlight certain aspects of the invention. Additional objects, aspects and embodiments of the invention are found in the following detailed description of the invention.
Unless specifically defined herein, all technical and scientific terms used have the same meaning as commonly understood by a skilled artisan in the fields of gene therapy, biochemistry, genetics, and molecular biology.
All methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, with suitable methods and materials being described herein. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will prevail. Further, the materials, methods, and examples are illustrative only and are not intended to be limiting, unless otherwise specified.
The practice of the present invention will employ, unless otherwise indicated, conventional techniques of cell biology, cell culture, molecular biology, transgenic biology, microbiology, recombinant DNA, and immunology, which are within the skill of the art. Such techniques are explained fully in the literature. See, for example, Current Protocols in Molecular Biology (Frederick M. AUSUBEL, 2000, Wiley and son Inc, Library of Congress, USA); Molecular Cloning: A Laboratory Manual, Third Edition, (Sambrook et al, 2001, Cold Spring Harbor, N.Y.: Cold Spring Harbor Laboratory Press); Oligonucleotide Synthesis (M. J. Gait ed., 1984); Mullis et al. U.S. Pat. No. 4,683,195; Nucleic Acid Hybridization (B. D. Harries & S. J. Higgins eds. 1984); Transcription And Translation (B. D. Hames & S. J. Higgins eds. 1984); Culture Of Animal Cells (R. I. Freshney, Alan R. Liss, Inc., 1987); Immobilized Cells And Enzymes (IRL Press, 1986); B. Perbal, A Practical Guide To Molecular Cloning (1984); the series, Methods In ENZYMOLOGY (J. Abelson and M. Simon, eds.-in-chief, Academic Press, Inc., New York), specifically, Vols. 154 and 155 (Wu et al. eds.) and Vol. 185, “Gene Expression Technology” (D. Goeddel, ed.); Gene Transfer Vectors For Mammalian Cells (J. H. Miller and M. P. Calos eds., 1987, Cold Spring Harbor Laboratory); Immunochemical Methods In Cell And Molecular Biology (Mayer and Walker, eds., Academic Press, London, 1987); Handbook Of Experimental Immunology, Volumes I-IV (D. M. Weir and C. C. Blackwell, eds., 1986); and Manipulating the Mouse Embryo, (Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1986) and updated versions.
According to a first aspect of the present invention is a method of generating and assembling polynucleotides comprising arrays of at least two highly similar polynucleotidic modules comprising the steps of:
In a preferred embodiment, A and A′ are identical.
In another embodiment, at least one said polynucleotidic building block comprise a pre-assembly of more than one polynucleotidic module. In another embodiment, said polynucleotidic building blocks of the present invention comprise a pre-assembly of more than one polynucleotidic module. As non-limiting examples, said polynucleotidic building blocks of the present invention comprise a pre-assembly of 2, 3, 4, 5, 6, 7, 8, 9 or 10 polynucleotide modules. As other non-limiting examples, said polynucleotidic building blocks of the present invention comprise a pre-assembly of more than 10 polynucleotide modules, i.e., 11, 12, 13, 14, 15, 20, 30, 40, 50 or 100. In another embodiment more than 100 polynucleotides are pre-assembled in said building block according to the present invention.
In another embodiment, said polynucleotidic building blocks of the present invention can be partially or entirely generated by oligonucleotide synthesis from digital nucleic sequences of said polynucleotidic building blocks and subsequent annealing of the resultant polynucleotidic intermediate; said oligonucleotides being designed and synthesize to produce polynucleotidic building blocks with compatible cohesive ends with or without enzymatic reactions. In another embodiment, some of the building blocks used for the generation of polynucleotides comprising an array of polynucleotidic modules according to the present invention can be generated by oligonucleotide synthesis from digital nucleic sequences, said oligonucleotides being designed and synthesize to produce polynucleotidic building blocks with compatible cohesive ends with or without enzymatic reactions.
In another embodiment, said single cleavage sites respectively for restriction enzymes A and B are two different cleavage sites cleavable by restriction enzymes which produce compatible cohesive overhang ends and wherein said compatible cohesive overhangs remove respective recognition sites for said restriction enzymes A and B upon ligation. In other words, restriction enzymes A and B according to the present invention produce at their respective single cleavage site compatible overhang cohesive ends without restoring a sequence cleavable by restriction enzymes A and B after ligation. In another embodiment, said restriction enzymes A and B belong to subtypes of class II restriction enzymes such as subtypes A, B, C, H and S as listed for example at http://_rebase.neb.com. In another embodiment, said restriction enzymes A and B of the present invention belong to typeIIS restriction enzymes. In a preferred embodiment said restriction enzymes A and B of the present invention are BbvI and SfaNI.
In another embodiment, said single cleavage sites respectively for restriction enzymes A and B can be cleavage sites for other enzymes such as nick-creating enzymes (nickases as non-limiting examples) under appropriate use to generate compatible overhang cohesive ends.
In another embodiment, said polynucleotide of c) is the first polynucleotide (considering a 5′-3′ reading) comprising a polynucleotide module of the final polynucleotide comprising an array of polynucleotidic modules.
In another embodiment, said first polynucleotide of c) comprises a fragment of building block according to a).
In another embodiment, said polynucleotide of c) is the last polynucleotide (considering a 5′-3′ reading) comprising a polynucleotide module of the final polynucleotide comprising an array of polynucleotidic modules.
In another embodiment, said last polynucleotide of c) comprises:
In another embodiment, said first polypeptide of c) has been generated by:
In another embodiment, the present invention is a method of generating and assembling polynucleotides comprising arrays of at least two highly similar polynucleotidic modules comprising the steps of:
In a preferred embodiment, A and B are identical.
In another embodiment, said polynucleotide sequence not highly similar to a polynucleotide module according to a) is linked to said solid phase. In another embodiment, said polynucleotide sequence not highly similar to a polynucleotide module according to a) encodes a N-terminal polypeptidic sequence of a TALE. In another embodiment, said polynucleotide sequence not highly similar to a polynucleotide module according to a) encodes a C-terminal polypeptidic sequence of a TALE. In another embodiment, said polynucleotide sequence not highly similar to a polynucleotide module according to a) encodes a C-terminal polypeptidic sequence of a TALE and a half Transcription Activator-like Effector (TALE) DNA binding repeat module. In another embodiment, said polynucleotide sequence not highly similar to a polynucleotide module according to a) encodes one protein domain able to process a nucleic acid target sequence adjacent to the nucleic acid sequence bound by a TALE DNA binding domain, thus producing a chimeric protein according to the method of the present invention comprising a set of repeated modules with RVDs to bind a nucleic acid sequence and one protein domain to process a nucleic acid target sequence adjacent to said bound nucleic acid sequence.
In another embodiment, said polynucleotidic building blocks according to the present invention can encode a polynucleotidic module that is not highly similar to the other polynucleotidic modules assembled according to the method of the present invention to produce polynucleotides comprising an array of polynucleotidic modules. As non-limiting example, said polynucleotidic building blocks according to the present invention can encode a protein domain able to process a nucleic acid target sequence adjacent to the nucleic acid sequence bound by the other polynucleotidic modules of the array. Position of said not highly similar module can be anywhere in the array. As a non-limiting example a polynucleotide comprising an array of polynucleotidic modules according to the present invention can comprise a succession of: 7,5 highly similar TALE repeat polynucleotidic modules—a not highly similar polynucleotidic module encoding a protein domain—7,5 highly similar TALE repeat polynucleotidic modules. In another embodiment, said polynucleotide comprising an array of polynucleotidic modules according to the present invention can comprise more than one not highly similar polynucleotidic module.
In another embodiment, the end of said polynucleotide of c) linked to a solid phase comprises a single cleavage site for a restriction enzyme C, wherein said cleavage of said site with restriction enzyme C allows to unlink said polynucleotide from the solid phase. In another embodiment of this aspect of the invention, said restriction enzyme C is SfiI. In another embodiment, said single cleavage site for a restriction enzyme C is cleavable by said restriction enzyme A or said restriction enzyme B and said final polynucleotide comprising an array of polynucleotidic modules comprises no sequence cleavable by restriction enzymes A or B.
In another embodiment, said method of the present invention further comprises the step of unlinking said final polynucleotide of step i) comprising an array of polynucleotidic modules, by unlinking it with in non enzymatic step such as chemical or ionic treatments well-known in the art.
In another embodiment, said method of the present invention further comprises the step of unlinking said final polynucleotide of step i) comprising an array of polynucleotidic modules, by cutting it with a restriction enzyme. In another embodiment, said restriction enzyme is a restriction enzyme C different than restriction enzymes A and B. In another embodiment, said restriction enzyme is A or B.
In another embodiment, each of said polynucleotidic modules to assemble according to the present invention encodes a Transcription Activator-like Effector (TALE) DNA binding repeat module. Said Transcription Activator-like Effector (TALE) DNA binding repeat module usually comprises between 8 and 30 repeated modules (or repeat modules), more frequently between 8 and 20 repeat modules, again more frequently 15 repeat modules. The assembly of said repeated modules produce a TALE binding domain. Said repeat modules usually encode for 30 to 42 amino acids, more preferably 33-35 amino acids wherein two critical amino acids of each repeat module located at positions 12 and 13 (Repeat Variable Diresidues, RVD), mediate the recognition of one nucleotide of the nucleic acid target sequence targeted by the entire Transcription Activator-like Effector (TALE) DNA binding domain; said polynucleotidic modules according to the present invention can encode for TALE repeat modules comprising equivalent two critical amino acids located at positions other than 12 and 13 specialy in repeat modules taller than 33-35 amino acids long. In another embodiment, said polynucleotidic repeat modules of the present invention can encode for repeat modules-like domains or RVDs-like domains. RVDs-like domains have a sequence different from naturally occurring polynucleotidic repeat modules comprising RVDs (RVDs domains) but have a similar function and/or global structure. As non-limiting examples, said RVDs-like domains are protein domains selected from the group consisting of Puf RNA binding protein or Ankyrin super-family. Non-limiting examples of such proteins from which RVDs-like domain can be derived are given by SEQ ID NO: 4 and SEQ ID NO: 5 respectively corresponding to proteins fem-3 and aRep. Depending on the structural context and binding constraints, said polynucleotidic modules to assemble according to the present invention encodes a Transcription Activator-like Effector (TALE) DNA binding domain that comprises a mix of naturally occurring RVDs structures and RVDs-like domains. In another embodiment, said polynucleotidic TALE repeat modules to assemble according to the present invention encodes a totally artificial Transcription Activator-like Effector (TALE) DNA binding domain i.e., without any repeated domains derived from naturally occurring TAL effectors.
In another embodiment, said polynucleotidic building block of b) encodes a half repeat module of a Transcription Activator-like Effector (TALE) DNA binding repeat module. Said half repeat module is equivalent to the truncated repeat module usually made of 20 amino acids that is located at the C-terminus of said Transcription Activator-like Effector (TALE) DNA binding repeat module. In this case, said Transcription Activator-like Effector (TALE) DNA binding repeat module comprises between 8.5 and 30.5 repeat modules, “0.5” referring to previously mentioned half repeat module (or terminal repeat module, or half-repeat). More frequently, said Transcription Activator-like Effector (TALE) DNA binding repeat module comprises between 8.5 and 20.5 repeat modules, again more frequently, 15.5 repeat modules.
In another embodiment, said polynucleotidic building block of b) encodes a half TALE repeat module and one TALE mono repeat module (i.e. one and half TALE repeat module). In another embodiment, said polynucleotidic building block of b) encodes a half Transcription Activator-like Effector (TALE) DNA binding repeat module and a C-terminal fragment of a TALE. In another embodiment, said building block of b) encodes a N-terminal fragment of a TALE.
In another embodiment, said polynucleotidic modules to assemble share at least 85% similarity. In another embodiment, said polynucleotidic modules to assemble share 86, 87, 88, 89 or 90% similarity. In another embodiment, said polynucleotidic modules to assemble share 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100% similarity.
BLASTP may also be used to identify an amino acid sequence having at least 80%, 85%, 87.5%, 90%, 92.5%, 95%, 97.5%, 98%, 99% sequence similarity to a reference amino acid sequence using a similarity matrix such as BLOSUM45, BLOSUM62 or BLOSUM80. Unless otherwise indicated a similarity score will be based on use of BLOSUM62. When BLASTP is used, the percent similarity is based on the BLASTP positives score and the percent sequence identity is based on the BLASTP identities score. BLASTP “Identities” shows the number and fraction of total residues in the high scoring sequence pairs which are identical; and BLASTP “Positives” shows the number and fraction of residues for which the alignment scores have positive values and which are similar to each other. Amino acid sequences having these degrees of identity or similarity or any intermediate degree of identity of similarity to the amino acid sequences disclosed herein are contemplated and encompassed by this disclosure.
As previously mentioned, said polynucleotidic modules to assemble according to the present invention can encode Transcription Activator-like Effector (TALE) DNA binding repeat modules. The assembly of such polynucleotidic modules produces a TALE binding domain. Said Transcription Activator-like Effector (TALE) DNA binding domain usually comprises between 8 and 30 repeated modules (or repeat modules, or TALE repeat modules), more frequently between 8 and 20 repeat modules, again more frequently 15 repeat modules. Said repeat modules usually encode for 30 to 42 amino acids, more preferably 33-35 wherein two critical amino acids located at positions 12 and 13 (Repeat Variable Diresidues, RVD) mediate the recognition of one nucleotide of the nucleic acid target sequence targeted by the entire Transcription Activator-like Effector (TALE) DNA binding domain. Preferably, RVDs associated with recognition of the different nucleotides are HD for recognizing C, NG for recognizing T, NI for recognizing A, NN for recognizing G or A, NS for recognizing A, C, G or T, HG for recognizing T, IG for recognizing T, NK for recognizing G, HA for recognizing C, ND for recognizing C, HI for recognizing C, HN for recognizing G, NA for recognizing G, SN for recognizing G or A and YG for recognizing T. More preferably, RVDs associated with recognition of the nucleotides C, T, A, G/A and G respectively are selected from the group consisting of NN or NK for recognizing G, HD for recognizing C, NG for recognizing T and NI for recognizing A. In another embodiment, RVDs associated with recognition of the nucleotide C are selected from the group consisting of N* and RVDs associated with recognition of the nucleotide T are selected from the group consisting of N* and H*, where * denotes a gap in the repeat sequence that corresponds to a lack of amino acid residue at the second position of the RVDs. In another embodiment, critical amino acids 12 and 13 can be mutated towards other amino acid residues in order to modulate their specificity towards nucleotides A, T, C and G and in particular to enhance this specificity. By other amino acid residues is intended any of the twenty natural amino acid residues or unnatural amino acids derivatives.
In another aspect of the present invention is a method wherein said “n” polynucleotidic building blocks are part of a collection encoding polypeptidic repeated modules or polypeptidic repeat modules with Repeat Variable Dipeptide regions (RVDs) comprising a pair of amino acids responsible for recognizing one nucleotide selected from the group consisting of HD for recognizing C, NG for recognizing T, NI for recognizing A, NN for recognizing G or A, NS for recognizing A, C, G or T, HG for recognizing T, IG for recognizing T, NK for recognizing G, HA for recognizing C, ND for recognizing C, HI for recognizing C, HN for recognizing G, NA for recognizing G, SN for recognizing G or A and YG for recognizing T. In a preferred embodiment of this aspect of the invention, is a method wherein said “n” polynucleotidic building blocks are part of a collection encoding polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) comprising a pair of amino acids responsible for recognizing one nucleotide selected from the group consisting of HD for recognizing C, NG for recognizing T, NI for recognizing A, NN and NK for recognizing G.
In another embodiment is a method wherein said “n” polynucleotidic building blocks are part of a collection encoding two polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing two nucleotides via two pairs of amino acids (TALE di repeat modules or di repeat modules) selected from the group listed in table 2 of example one below as non-limiting example.
In another embodiment is a method wherein said “n” polynucleotidic building blocks are part of a collection encoding three polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing three nucleotides via three pairs of amino acids (TALE tri repeat modules or tri repeat modules) selected from the group listed in table 3 of example one as non-limiting example.
In another embodiment is a method wherein said “n” polynucleotidic building blocks are part of a library encoding “n” polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing “n” nucleotides via “n” pairs of amino acids (TALE “n” repeat modules or “n” repeat modules). In another embodiment, “n” is comprised between 1 and 8. In another embodiment, “n” is 1, 2, 3, 4, 5, 6, 7 or 8.
In another embodiment, said polynucleotidic building block brought in previously described steps d) to g) of the method of the present invention is a unique molecular species comprising a precise sequence. In another embodiment, several polynucleotidic building blocks are brought in previously described steps d) to g) of the method of the present invention comprising each a precise sequence. In another embodiment, a library of polynucleotidic building blocks are brought in previously described steps d) to g) of the method of the present invention comprising a library of polynucleotidic modules. In another embodiment said library can be a random mutagenized library of polynucleotidic modules. In another embodiment, a library of polynucleotidic building blocks are used in previously described steps d) to g) of the method of the present invention comprising a library of polynucleotidic modules and encoding a library of TALE repeat polynucleotidic modules. Mutagenesis can concern the entire polynucleotidic module sequence. In another embodiment said library can be a random mutagenized library of TALE repeat polynucleotidic modules. Mutagenesis of said TALE repeat polynucleotidic modules library can focused on critical amino acids such as amino acids located at positions 12 and 13 as non-limiting examples. Mutagenesis of said TALE repeat polynucleotidic modules library can focused on other critical amino acids of said TALE repeat polynucleotidic modules. Mutagenesis of said TALE repeat polynucleotidic modules library may concern the entire TALE repeat module sequence. Said libraries of polynucleotidic modules constituting libraries of polynucleotidic building blocks can be used according to the method of the present invention to introduce diversity into polynucleotides comprising an array of polynucleotidic modules. As non-limiting example, the method according to the present invention is particularly well-suited to introduce diversity into TALE repeat polynucleotidic modules in order to produce high-diversity libraries of TALE DNA binding domains.
According to another aspect of the present invention is a method of generating and assembling polynucleotides comprising arrays of at least two highly similar polynucleotidic modules comprising the steps of:
In a preferred embodiment, steps e) and g) are respectively followed by washing steps such as three washes with an adapted volume of saline buffer such as PBS well known in the art.
In another embodiment, steps f) and g) are repeated N times to produce an immobilized polynucleotide having an array of n polynucleotidic modules wherein n=N+3.
In another embodiment, step g) is replaced by the following steps:
In a preferred embodiment, “x” can be any number comprised between 1 and 50, preferably, between 1 and 20, more preferably, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1.
In a preferred embodiment, steps h) and j) are respectively followed by washing steps such as three washes with an adapted volume of saline buffer such as PBS well known in the art.
In another embodiment, said method of this aspect of the present invention further comprises the steps:
In a preferred embodiment, step b) is respectively followed by washing steps such as three washes with an adapted volume of saline buffer such as PBS well known in the art.
In another embodiment, at least one said polynucleotidic building block of a) and/or at least one polynucleotide linked to a solid phase of b) and/or said polynucleotidic building block of c) comprise a pre-assembly of more than one polynucleotidic module.
In another embodiment, at least one said polynucleotidic building block of a) and/or at least one polynucleotide linked to a solid phase of b) and/or said polynucleotidic building block of c) comprise a fragment of building block. In another embodiment, said fragment of building block is a building block deleted at its 3′ end. In another embodiment, said fragment of building block is a building block deleted in its center. In another embodiment, said fragment of building block encodes at least a half Transcription Activator-like Effector (TALE) DNA binding repeat module.
In another embodiment, at least one said polynucleotidic building block of a) and/or at least one polynucleotide linked to a solid phase of b) and/or said polynucleotidic building block of c) comprise a building block variant.
In another embodiment, at least one said polynucleotidic building block of a) and/or at least one polynucleotide linked to a solid phase of b) and/or said polynucleotidic building block of c) comprise a polynucleotide sequence not highly similar to a polynucleotide module according to a).
In another embodiment, at least one said polynucleotidic building block of a) and/or at least one polynucleotide linked to a solid phase of b) and/or said polynucleotidic building block of c) further comprises a fragment of building block according to a).
In another embodiment, said one polynucleotide of b) has been generated by:
In another embodiment, said one polynucleotide of b) has been generated by:
In another embodiment, said one polynucleotide of b) has been generated by:
In another embodiment, said one polynucleotide of b) has been generated by:
In another embodiment, at least one polynucleotide linked to a solid phase of b) has been generated by a gene synthesis technology wherein said free end compatible with the cohesive ends resulting from cleavage with restriction enzyme A has been obtained by using restriction enzymes or specific annealing and wherein said polynucleotide ligation with a polynucleotidic building block cleaved by restriction enzyme A will not produce at least a sequence cleavable by restriction enzyme A and/or B.
In another embodiment, said at least one polynucleotide linked to a solid phase of b) has been generated by:
wherein annealing of both oligonucleotides in appropriate conditions generates, without using restriction enzymes, a double stranded polynucleotide with a free end compatible with the cohesive ends resulting from cleavage with restriction enzyme A, and which ligation with a polynucleotidic building block cleaved by restriction enzyme A will not produce a sequence cleavable by restriction enzyme A and/or B.
Parameters for reaching annealing appropriate conditions of oligonucleotides are well known in the art.
In another embodiment, said at least one polynucleotide linked to a solid phase of b) has been generated by:
wherein annealing of both oligonucleotides in appropriate conditions generates a double stranded polynucleotide with a single cleavage site for a second restriction enzyme B placed on the side of the polynucleotide that is not linked to a solid phase;
In another embodiment, said polynucleotide sequence not highly similar to a polynucleotide module according to a) is linked to said solid phase.
In another embodiment, at least one said polynucleotide linked to a solid phase of b) comprises a sequence not highly similar to a polynucleotide module according to a) encoding a N-terminal polypeptidic sequence of a TALE.
In another embodiment, at least one said polynucleotidic building block of a) and/or said polynucleotidic building block of c) comprises a sequence not highly similar to a polynucleotide module according to a) encoding a C-terminal polypeptidic sequence of a TALE.
In another embodiment, at least one said polynucleotidic building block of a) and/or at least one polynucleotide linked to a solid phase of b) and/or said polynucleotidic building block of c) further comprises at least one cleavage site for a restriction enzyme C located outward compared to restriction enzymes A and/or B cleavage sites.
In another embodiment, the last polynucleotide of b) used comprises a single cleavage site for a restriction enzyme C placed on the side of the polynucleotide linked to a solid phase, located outward compared to restriction enzyme A cleavage site, wherein said cleavage with restriction enzyme C allows to unlink said polynucleotide from the solid phase.
In another embodiment of the invention is a method further comprising the step of unlinking said final polynucleotide comprising an array of polynucleotidic modules by cutting it with restriction enzyme C.
In another embodiment of the invention is a method further comprising the steps of:
In another embodiment, said method further comprises the step of subcloning said final polynucleotide comprising an array of polynucleotidic modules from a plasmidic vector into another plasmidic vector by cutting it with restriction enzymes A and B;
In another embodiment of the invention is a method further comprising the steps of:
In another embodiment of this aspect of the invention is a method wherein said polynucleotidic modules to assemble share at least 85% similarity.
In another embodiment of this aspect of the invention is a method wherein each polynucleotidic module encodes a Transcription Activator-like Effector (TALE) DNA binding repeat module.
In another embodiment of this aspect of the invention is a method wherein said polynucleotide sequence not highly similar to a polynucleotide module according to a) encodes a C-terminal fragment of a TALE and wherein said fragment of building block encodes at least a half Transcription Activator-like Effector (TALE) DNA binding repeat module.
In another embodiment of this aspect of the invention, said single cleavage sites respectively for restriction enzymes A and B are two different cleavage sites cleavable by restriction enzymes which produce compatible cohesive overhang ends and wherein said compatible cohesive overhangs remove respective recognition sites for said restriction enzymes A and B upon ligation. In other words, restriction enzymes A and B according to the present invention produce at their respective single cleavage site compatible overhang cohesive ends without restoring a sequence cleavable by restriction enzymes A and B after ligation. In another embodiment, said restriction enzymes A and B belong to subtypes of class II restriction enzymes such as subtypes A, B, C, H and S as listed for example at http://_rebase.neb.com. In another embodiment, said restriction enzymes A and B of the present invention belong to typeIIS restriction enzymes. In a preferred embodiment said restriction enzymes A and B of the present invention are BbvI and SfaNI.
In another embodiment, said single cleavage sites respectively for restriction enzymes A and B can be cleavage sites for other enzymes such as nick-creating enzymes (nickases as non-limiting examples) under appropriate use to generate compatible overhang cohesive ends.
In another embodiment of this aspect of the invention, said restriction enzyme C is SfiI.
In another embodiment of this aspect of the invention is a method wherein said at least one polynucleotidic building block of a) and/or said polynucleotides of b) linked to a solid phase and/or said polynucleotidic building block of c) are part of a collection encoding polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) comprising a pair of amino acids responsible for recognizing one nucleotide selected from the group consisting of HD for recognizing C, NG for recognizing T, NI for recognizing A, NN for recognizing G or A, NS for recognizing A, C, G or T, HG for recognizing T, IG for recognizing T, NK for recognizing G, HA for recognizing C, ND for recognizing C, HI for recognizing C, HN for recognizing G, NA for recognizing G, SN for recognizing G or A and YG for recognizing T.
In another embodiment of this aspect of the invention, is a method wherein said at least one polynucleotidic building block of a) and/or said polynucleotides of b) linked to a solid phase and/or said polynucleotidic building block of c) are part of a collection encoding polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) comprising a pair of amino acids responsible for recognizing one nucleotide selected from the group consisting of HD for recognizing C, NG for recognizing T, NI for recognizing A, NN and NK for recognizing G.
In another embodiment of this aspect of the invention, is a method wherein said at least one polynucleotidic building block of a) and/or said polynucleotides of b) linked to a solid phase and/or said polynucleotidic building block of c) are part of a collection encoding “y” polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing “y” nucleotides via “y” pairs of amino acids wherein “y” is comprised between 1 and 8. In another embodiment, “y” equals 1, 2, 3, 4, 5, 6, 7 or 8.
In another embodiment of this aspect of the invention, is a method wherein said at least one polynucleotidic building block of a) and/or said polynucleotides of b) and/or said polynucleotidic building block of c) linked to a solid phase are part of a collection encoding two polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing two nucleotides via two pairs of amino acids selected from the group listed in table 2.
In another embodiment of this aspect of the invention, is a method wherein said at least one polynucleotidic building block of a) and/or said polynucleotides of b) and/or said polynucleotidic building block of c) linked to a solid phase are part of a collection encoding three polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing three nucleotides via three pairs of amino acids selected from the group listed in table 3.
In another embodiment of this aspect of the invention, is a method wherein said at least one polynucleotidic building block of a) and/or said polynucleotides of b) linked to a solid phase and/or said polynucleotidic building block of c) are part of a library of degenerated building blocks.
In another embodiment of this aspect of the invention, a library of polynucleotidic building blocks are processed in previously described steps d) to g), g′) and h) to j) of the method of the present invention comprising a library of polynucleotidic modules. In another embodiment said library can be a random mutagenized library of polynucleotidic modules. In another embodiment, a library of polynucleotidic building blocks are used in previously described steps d) to g), g′) and h) to j) of the method of the present invention comprising a library of polynucleotidic modules and encoding a library of TALE repeat polynucleotidic modules. Mutagenesis can concern the entire polynucleotidic module sequence. In another embodiment said library can be a random mutagenized library of TALE repeat polynucleotidic modules. Mutagenesis of said TALE repeat polynucleotidic modules library can focused on critical amino acids such as amino acids located at positions 12 and 13 as non-limiting examples. Mutagenesis of said TALE repeat polynucleotidic modules library can focused on other critical amino acids of said TALE repeat polynucleotidic modules. Mutagenesis of said TALE repeat polynucleotidic modules library may concern the entire TALE repeat module sequence. Said libraries of polynucleotidic modules constituting libraries of polynucleotidic building blocks can be used according to the method of the present invention to introduce diversity into polynucleotides comprising an array of polynucleotidic modules. As non-limiting example, the method according to the present invention is particularly well-suited to introduce diversity into TALE repeat polynucleotidic modules in order to produce high-diversity libraries of TALE DNA binding domains.
In another aspect of the present invention is a method of conducting a high throughput custom-designed platform of TALE DNA binding domains comprising:
In another embodiment “n” is comprised between 1 and 50, preferably 45, more preferably 40, more preferably 35, more preferably 30, more preferably, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1.
In another aspect of the present invention is a method of conducting a high throughput custom-designed platform of chimeric protein derived from a TALE comprising:
In another embodiment “n” is comprised between 1 and 50, preferably 45, more preferably 40, more preferably 35, more preferably 30, more preferably, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1.
In another aspect of the present invention is a kit for generating and assembling polynucleotides comprising arrays of at least two highly similar polynucleotidic modules according to the present invention comprising at least a collection of “n” polynucleotidic building blocks encoding “n” polypeptidic repeated modules with Repeat Variable Dipeptide regions (RVDs) for recognizing “n” nucleotides via “n” pairs of amino acids (TALE “n” repeat modules or “n” repeat modules) and instructions to use it.
In another aspect of the present invention is a method for producing high diversity libraries of polynucleotides comprising arrays of polynucleotidic modules encoding TALE DNA binding domains comprising:
By “polynucleotidic building block(s)” or “building block(s)” is intended polynucleotidic entities or polynucleotides comprising polynucleotidic modules to assemble according to the present invention. Said building block(s) comprises one or several polynucleotidic modules and allows the assembly of several polynucleotidic modules. In addition to polynucleotidic module(s), said polynucleotidic building block(s) can comprise one single cleavage site for a restriction enzyme or two single cleavage sites for different restriction enzymes and wherein cleavage of said polynucleotidic building blocks with restriction enzyme(s) result in compatible cohesive ends which allow the assembly of several polynucleotidic modules. In addition, said polynucleotidic building block(s) can comprise other polynucleotidic sequences not highly similar to a polynucleotidic module according to the present invention. A “fragment of polynucleotidic building block(s)” or “a fragment of building blocks” can be used in the present invention to describe a building block according to the present invention comprising only one single cleavage site for a restriction enzyme A or B or lacking one single cleavage site for a restriction enzyme A or B. A “fragment of polynucleotidic building block” can be deleted at its 3′ end, at its 5′ end or in its center. More generally, the expression “fragment of polynucleotidic building block” is used to describe a truncated polynucleotide building block.
By “degenerated building block” is intended a polynucleotidic building block which contains one difference or several differences at specific locations in its sequence compared to a polynucleotidic building block of reference. This particularly applies when diversity has to be introduced in said polynucleotidic building block. Degenerated polynucleotidic building blocks with partial or total diversity introduced at one or several locations of its nucleotidic codon sequence can be used to screen the best interaction of a polynucleotidic building block toward a DNA target sequence; as a non-limiting example, a DNA target sequence of interest can be used as a bait to screen a library of “degenerated building blocks” wherein each “degenerated building block” comprises a similar and related sequence containing diversity at one or several nucleotidic codons (and amino acids encoded by these codons).
By “polynucleotidic module(s)” or “modules” is intended polynucleotidic entities or polynucleotides to assemble according to the present invention. Said polynucleotidic module(s) can be highly similar modules such as TALE repeat modules as a non-limiting example. Highly similar modules present in multiple copies can be described as “repeated modules”.
“Pre-assembly” means that a polynucleotidic building block used to elongate the polynucleotidic modules assembly process according to the present invention can comprise more than one polynucleotidic module. In this case, said polynucleotidic building block can be described as pre-assembled.
By a “TALE-nuclease” (TALEN) is intended a fusion protein consisting of a DNA-binding domain derived from a Transcription Activator Like Effector (TALE) and one nuclease catalytic domain to cleave a nucleic acid target sequence. First published TALEN are formed by fusion of the cleavage domain of FokI and a TALE DNA binding domain.
By “TALE DNA binding domain” is intended part of a Transcription Activator Like Effector (TALE) responsible of DNA binding and composed by a variable number of 33-35 amino acids “repeat modules” or “TALE repeat polynucleotidic modules” or “TALE repeat modules” or “RVDs domains”. The nature of residues 12 and 13 determines base preferences of individual repeat module.
By “chimeric protein” according to the present invention is meant any fusion protein comprising a set of repeated modules with RVDs (or with RVDs-like domains) to bind a nucleic acid sequence and one protein domain to process a nucleic acid target sequence adjacent to said bound nucleic acid sequence. Said chimeric protein according to the present invention can function as a dimer wherein each monomer constituting said chimeric dimeric protein comprises a set of repeated modules with RVDs (or with RVDs-like domains) to bind a nucleic acid sequence and one protein domain to process a nucleic acid target sequence adjacent to said bound nucleic acid sequence. “identity” refers to sequence identity between two nucleic acid molecules or polypeptides. Identity can be determined by comparing a position in each sequence which may be aligned for purposes of comparison. When a position in the compared sequence is occupied by the same base, then the molecules are identical at that position. A degree of “similarity” or identity between nucleic acid or amino acid sequences is a function of the number of identical or matching nucleotides or amino acids at positions shared by the nucleic acid or polypeptidic sequences. Various alignment algorithms and/or programs may be used to calculate the identity between two sequences, including FASTA, or BLAST which are available as a part of the GCG sequence analysis package (University of Wisconsin, Madison, Wis.), and can be used with, e.g., default setting. Common software tools used for general sequence alignments taskes include ClustalW for alignment and BLAST or FASTA for database searching.
In sequence alignments of proteins, the degree of similarity between aminoacids occupying a particular position in the sequence can be interpreted as a rough measure of how conserved a particular region or a sequence motif is among lineages. The absence of substitutions in a particular region or sequence or the presence of only very conservative substitutions by amino acids whose side chains have similar biochemical properties, suggest that this region has structural or functional importance.
“Percent identity” or “percent similarity” are used to quantify the similarity between biomolecule sequences. For two naturally occurring sequences, percent identity is a factual measurement, whereas similarity is a hypothesis supported by evidence.
Amino acid residues in a polypeptide sequence can be designated herein according to the one-letter or three-letter code, in which, for example, Q means Gln or Glutamine residue, R means Arg or Arginine residue and D means Asp or Aspartic acid residue.
Amino acid substitution means the replacement of one amino acid residue with another, for instance the replacement of an Arginine residue with a Glutamine residue in a peptide sequence is an amino acid substitution.
Nucleotides are designated as follows: one-letter code is used for designating the base of a nucleoside: a is adenine, t is thymine, c is cytosine, and g is guanine. For the degenerated nucleotides, r represents g or a (purine nucleotides), k represents g or t, s represents g or c, w represents a or t, m represents a or c, y represents t or c (pyrimidine nucleotides), d represents g, a or t, v represents g, a or c, b represents g, t or c, h represents a, t or c, and n represents g, a, t or c.
by “DNA target”, “DNA target sequence”, “target DNA sequence”, “nucleic acid target sequence”, “target sequence”, or “target” is intended a polynucleotide sequence that is recognized by the DNA binding domain of a protein. These terms refer to a specific DNA location, preferably a genomic location in a cell, but also a portion of genetic material that can exist independently to the main body of genetic material such as plasmids, episomes, virus, transposons or in organelles such as mitochondria or chloroplasts as non-limiting examples. The nucleic acid target sequence is defined by the 5′ to 3′ sequence of one strand of said target.
by “generating” a polynucleotide, a polynucleotidic building block or another polynucleotidic entity is meant to synthesize or to make synthesize this entity by one of the gene synthesis methods well-known in the art. It is also encompassed in this definition the generation of said polynucleotidic entity by Polymerase Chain Reaction using appropriate oligonucleotide primers, degenerated or not, linked to a non-polynucleotidic entity, such as Biotin as a non-limiting example, or not.
by “variant”, “polynucleotidic building block variant”, “building block variant”, “chimeric protein variant” is intended a molecule obtained by replacement of at least one nucleotide, or at least one amino acid residue compared to a polynucleotidic building block, a building block or a chimeric protein, respectively taken as a reference. According to this definition, a variant can result from a truncation, or a mutation or a sequence insertion. Said inserted sequence can possibly be one or several nucleotides, one or several amino acids, one protein motif or one reporter protein.
The above written description of the invention provides a manner and process of making and using it such that any person skilled in this art is enabled to make and use the same, this enablement being provided in particular for the subject matter of the appended claims, which make up a part of the original description.
As used above, the phrases “selected from the group consisting of,” “chosen from,” and the like include mixtures of the specified materials.
Where a numerical limit or range is stated herein, the endpoints are included. Also, all values and subranges within a numerical limit or range are specifically included as if explicitly written out.
The above description is presented to enable a person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, this invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
Having generally described this invention, a further understanding can be obtained by reference to certain specific examples, which are provided herein for purposes of illustration only, and are not intended to be limiting unless otherwise specified.
1a—Construction of Polynucleotidic Building Blocks Comprising TALE Repeat Polynucleotidic Modules
TALE repeat polynucleotidic modules or repeat modules or TALE repeat modules of AvrBS3 from Xanthomonas spp. plant pathogen, containing the RVDs NN, NK, NI, HD, NG and the terminal half repeat NG* are synthesized and cloned in the pAPG10 plasmid between restriction sites AscI and PacI (SEQ ID NO: 6-12,
As an illustrative example, to prepare the building block encoding di repeat module 1-2, pAPG10 encoding the repeat modules 1 and 2 [building blocks encoding modules 1 and 2 (SEQ ID NO: 13 and 14)] are first digested by SfiI (
1b—Sequential Assembly of TALE Repeat Polynucleotidic Modules
A method to assemble TALE repeat polynucleotidic modules comprised in polynucleotidic building blocks (or TALE building blocks) was designed according to the following protocol. It should be noted that TALE building blocks may contain multiple TALE repeat modules obtained from previous assemblies. As illustrated in
a—Choose a plasmid containing the first building block encoding the desired TALE di repeat module, extract it with SfiI and SfaNI restriction enzymes (polynucleotidic module A), and purify it on column (As an illustrating non-limiting example a TALE di repeat module HD_NI digested by SfiI and SfaNI is given by SEQ ID NO: 26);
b—Choose the plasmid containing the appropriate second building block encoding the desired second TALE di repeat module, extract it with SfiI and BbvI restriction enzymes (polynucleotidic module B), and purify it on column (As an illustrating non-limiting example a TALE di repeat module NG_NK digested by SfiI and SfaNI is given by SEQ ID NO: 27);
c—Ligate polynucleotidic modules A and B and purify the ligation product (polynucleotide AB) on column (Resulting TALE four repeat module HD_NI_NG_NK is given by SEQ ID NO: 28);
d—In parallel, repeat steps (a)-(c) using the appropriate plasmids in order to generate polynucleotide CD;
e—Digest polynucleotide AB with SfaNI and polynucleotide CD with BbvI and purify both of them on column;
f—Ligate polynucleotides AB with CD together with SfiI digested pAPG10 and transform it in DH5α E. coli;
g—PCR Screen for polynucleotides having the size of ABCD (8 TALE repeats polynucleotide);
h—Extract the 8 TALE repeats polynucleotide with SfiI and SfaNI restriction enzyme (polynucleotide ABCD) and purify it on column;
i—Repeat steps (a)-(g) using the appropriate plasmids to generate polynucleotide EFGH (with polynucleotide H encoding the last half RVD);
j—Extract the 7.5 TALE repeats polynucleotide with SfiI and BbvI restriction enzyme (polynucleotide EFGH) and purify it on column;
k—Ligate polynucleotides ABCD and EFGH together with SfiI digested pAPG10 and transform ligation products in DH5 a E. coli;
l—Colony PCR screen for polynucleotides having the size of ABCDEFGH (15.5 TALE repeats polynucleotide).
1c—Materials and Methods
Preparation of TALE Repeat Polynucleotidic Modules
To prepare TALE repeat polynucleotidic modules for subsequent assembly, pAPG10 bearing TALE repeat polynucleotidic modules were first digested by SfiI. Digestion mixture consisted in 100 μL of a pAPG10 maxiprep containing the desired module (1 μg/μL), 5 μL SfiI (75 U, NEB), 12 μL NEB3 buffer (NEB), 1.2 μL BSA 100× and 1.8 μL H20. Digestion was allowed to proceed for 1 hour at 50° C. Digestion products were separated on a 0.8% agarose gel and SfiI digested TALE repeat polynucleotides were extracted from the gel using Nucleospin extract II kit (Macherey-Nagel) and recovered in 35 μL H20. 25 μL of extracted TALE repeat polynucleotides were then added to either SfaNI or BbvI digestion mixtures. SfaNI and BbvI digestion mixtures contained 2 μL of restriction enzymes (3U), 3 μL of NEB3 or NEB2 10× respectively and 5 μL H20. Digestion was allowed to proceed for 1 hour at 37° C. Digested products were then column purified using Nucleospin extract II kit (Macherey-Nagel) and recovered in 35 L H20. The overall process generated about 5 μg of digested TALE repeat polynucleotidic module ready for assembly.
Assembly of 15.5 TALE Repeats Polynucleotide
To assemble the 15.5 TALE repeats polynucleotide CAPT1.3 described in this example, the 8 first TALE repeats polynucleotide and the 7.5 last TALE repeats polynucleotide (named respectively 8 TALE repeats left and 7.5 TALE repeat right in
Assembly of 8 TALE Repeats Left and 7.5 TALE Repeats Right Polynucleotides
Concerning the assembly of the 8 TALE repeats left polynucleotide, 5 μL of SfaNI digested first TALE di repeat module Rvd_b1 (20 ng/μL), was first ligated with 5 μL of Bbv I digested Rvd_b16 (20 ng/μL) in the presence of 1 μL of T4 DNA ligase (3U, promega) and 10 μL of 2× rapid ligation buffer (Promega). Ligation was allowed to proceed for 1 hour at room temperature. Ligation product was then column purified using the Nucleospin extract II kit (Macherey-Nagel) and eluted in 35 μL H20. 10 μL of the purified ligation product Rvd_b1-Rvd_b16 was then added to the SfaNI digestion mixture containing 1 μL SfaNI fast digest (Fermentas) and 10 μL fast digest buffer 2×(Fermentas). Digestion was allowed to proceed for 1 hour at 37° C. and the digestion product was then purified using Nucleospin extract II kit (Macherey-Nagel) and eluted in 35 μL H20. In parallel, the third and the fourth TALE di repeat polynucleotide Rvd_b15 and Rvd_b9 were ligated together and the ligation product was purified according to the same protocol. 10 μL of the purified ligation product Rvd_b15-Rvd_b9 was then added to the BbvI digestion mixture containing 1 μL BbvI (Fermentas) and 10 μL BbvI digestion buffer 2× (Fermentas). Digestion was allowed to proceed for 1 hour at 65° C. and the digestion product was purified using Nucleospin extract II kit (Macherey-Nagel) and eluted in 35 μL H20.
To complete the assembly of 8 TALE repeats left polynucleotide, 5 μL of SfaNI digested Rvd_b1-Rvd_b16 was added to 5 μL of BbvI digested Rvd_b15-Rvd_b9 in the presence of 1 μL of T4 DNA ligase (3U, Promega) in a final volume of 20 μL of rapid ligation buffer 1× (Promega). Ligation was allowed to proceed for 45 min at room temperature. To subclone the 8 TALE repeats left polynucleotide into pAPG10, 5 μL of the ligation product was mixed with 1 μL of SfiI digested pAPG10 cut vector (20 ng/μL), 5 μL of Rapid ligation buffer and 1 μL of T4 DNA ligase (Promega). Ligation was allowed to proceed for 30 min at room temperature.
5 μL of this ligation mixture was added to 30 μL of E. coli DH5α chimio competent cells (Invitrogen). Cells were transformed according to the manufacturer guidelines and plated on LB AGAR plates supplemented by ampiciline.
Transformants containing pAPG10 bearing the 8 TALE repeats left polynucleotide were identified by colony PCR screening using M13_F and M13_R as PCR primers (SEQ ID NO: 24-25).
The same procedure was used to generate and select the 7.5 TALE repeats left polynucleotide using Rvd_b1, Rvd_b12 and Rvd_T1
Coupling of 8 TALE Repeats Left and 7.5 TALE Repeats Right Polynucleotides
To generate the final 15.5 TALE repeats polynucleotide CAPT1.3, the 8 TALE repeats left and 7.5 TALE repeat right polynucleotides were first extracted from pAPG10 and then ligated together.
TALE repeats left and right polynucleotides were extracted from pAPG10 by SfiI digestion and gel purification. To do so, 20 μL of pAPG10 DNA preparation containing either TALE repeats left or right polynucleotides was added to a mixture containing 2 μL
SfiI (40U, NEB), 3 μL of BSA 10×, 3 μL, of NEB 4 buffer 10× (NEB), and 2 μL H20. The digestion was allowed to proceed 1 hour at 50° C. Digestion products were run onto 0.8% agarose gel and extracted using Nucleospin extract II kit (Macherey-Nagel) and 35 μL H20 for sample elution.
10 μL of purified 8 TALE repeats left or 7.5 TALE repeat right polynucleotides were then added to digestion mixtures containing SfaNI or BbvI respectively. Digestion mixtures contained 1 μL of restriction enzyme (either SfaNI Fast digest or BbvI, Fermentas) in a final volume of 10 μL of SfaNI or BbvI digestion buffer 2× (Fermentas). Digestion was allowed to proceed for 1 hour. Digestion products were purified using Nucleospin extract II kit (Macherey-Nagel) and eluted in 35 μL H2O.
5 μL of SfaNI digested 8 TALE repeats left polynucleotides were added to 5 μL of BbvI digested 7.5 TALE repeats right polynucleotides in the presence of 10 μL of Fast Ligase buffer 2× (Promega) and 1 μL of T4 DNA ligase (Promega). The ligation was allowed to proceed for 1 hour at room temperature. 1 μL of SfiI digested pAPG10 cut vector (20 ng/μL) was then added to the ligation mixture and the reaction was allowed to proceed for 30 min at room temperature. 3 μL of this ligation mixture was added to 30 μL of DH5α chimio competent cells (Invitrogen). Cells were transformed according to the manufacturer guidelines and plated on LB AGAR plates supplemented by ampiciline. Transformants containing pAPG10 bearing the 15.5 TALE repeats polynucleotide CAPT1.3 were identified by colony PCR screening using M13_F and M13_R as PCR primers (SEQ ID NO: 24-25).
1d—Assembly of TALE Repeats Polynucleotides CAPT1.3 and CAPT1.4 (15.5 TALE Repeats Polynucleotides)
The method described above was used to generate 2 different 15.5 TALE repeats polynucleotide s that recognize the heterodimeric target CAPT1.1 (SEQ ID NO: 32) (
1e—Generation of Libraries of TALE Di and Tri Repeat Modules
During assembly of TALE DNA binding domains, assembly intermediates containing TALE di or tri repeats were recovered and used to generate libraries of TALE-encoding building blocks. A complete set of pAPG10 plasmids encoding all the 20 possible TALE di repeat modules and all the 64 possible TALE tri repeat modules (including the last terminal half repeat module) was generated. These libraries of TALE-encoding building blocks were used to assemble custom TALE repeats according to the method described in this example and in examples 2 and 3.
Below in tables 1 to 3 are displayed libraries of mono, di and tri repeat modules.
1a—Method for Parallel Sequential Assembly of TALE Repeat Polynucleotidic Modules Using a Streptavidin Coated Well and Streptavidin Coated Magnetic Beads as Solid Phases.
An efficient and highly versatile high throughput method for TALE DNA binding domains was implemented. It consists in a sequential assembly of TALE repeat polynucleotidic modules (constituting a TALE DNA binding domain) comprised in polynucleotidic building blocks on a streptavidin coated solid phase supported by a 96 well plate format. In this method, the first polynucleotidic building block of the TALE repeat polynucleotide to assemble is biotinylated on 5′. This first biotinylated polynucleotidic building block is immobilized onto a streptavidin-coated solid phase (either streptavidin-coated well or magnetic beads) and serves as an anchor for TALE repeat polynucleotidic modules assembly. TALE repeat polynucleotidic modules assembly proceeds through a sequential addition of TALE-encoding building blocks according to the method described in example 1.
1a—Sequential and Parallel Assembly Process
We used two types of streptavidin coated solid phases:
The handling of both solid phases is essentially the same. However, there are two main differences between the two, the reaction volume (100 μL for streptavidin coated wells and 50 μL for streptavidin coated magnetic beads), and the need of a magnet for streptavidin coated magnetic beads. As illustrated in
This method includes the following steps:
1b—Materials and Methods
PCR Amplification and Digestion of TALE Building Blocks
Respectively, the first TALE building blocks of left and right TALE repeat polynucleotides were amplified from pAPG10 using TAL_Shuttle_Bio_Forward and TAL_Shuttle_Reverse primers (SEQ ID NO: 29 and 30 respectively). TAL_Shuttle_Bio_Forward contained a biotinylated moiety that binds specifically to the streptavidin coated solid phase. TALE repeat polynucleotidic modules or TALE repeat polynucleotides used for subsequent assembly could be obtained via the method described in section 1a, and could be also obtained by PCR using TAL_Shuttle_short_Forward and TAL_Shuttle_Reverse primers (SEQ ID NO 31 and 30). Conditions for amplification were 5 ng of pAPG10 containing mono or multiple TALE repeat polynucleotidic modules, 250 μM dNTP mix, 200 nM of each oligonucleotide, 1 μL of Herculase II Fusion DNA Polymerase (Agilent) in a final volume of 50 μL of Herculase buffer 1×. PCR was initiated by a 5 min denaturation at 95° C. followed by 30 cycles of 30 sec denaturation at 95° C., 30 sec annealing at 48° C. and 20 sec elongation at 72° C. This was followed by a 3 min elongation at 72° C. PCR products were column-purified using nucleospin extract II kit (Macherey-Nalgen), recovered in 40 μL H20 and digested by 10 U of either BbvI or SfaNI (NEB), in NEB 2 and 3 buffers, respectively, for 2 hours at 37° C. Digested PCR products were then column-purified using the nucleospin extract II kit (Macherey-Nalgen), recovered in 40 μL H20 and quantified using a nanodrop device (Thermo scientific). 2 μg of purified digested PCR products were typically obtained with this process.
Immobilisation of TALE Polynucleotidic Building Blocks on Streptavidin Coated Solid Phase
Two types of streptavidin coated solid phases were used for TALE repeat polynucleotides assembly. These are streptavidin coated magnetic beads (Ademtech) and Streptavidin coated plates (Thermo Scientific). Below are described the methods to immobilize biotinylated DNA on both solid phases.
Streptavidin Coated Magnetic Beads
To prepare the streptavidin coated magnetic beads for TALE repeat polynucleotides assembly, 10 μL of streptavidin magnetic beads (Ademtech, Masterbeads streptavidin, 500 nm, ref #03150) were added to 90 μL PBS 1×, pH7.5 (buffer A) in a 1.5 mL tube (Eppendorff, low binding, DNAase and RNAase free). The mixture was washed 3 times with 100 μL buffer A using the magnet provided by the manufacturer (ref #20105). Beads were then resuspended by pipetting up and down 3 times (off magnet) with 50 μL of biotinylated SfaNI digested di repeat module (prediluted with buffer A to a suitable concentration, see below) and incubated for 30 min at room temperature. The mixture was then placed onto the magnet to remove the supernatant, beads were washed 2 times with 100 μL of PBS 1×, 1M NaCL, pH7.5 (buffer B) to remove nonspecific binding complexes, and then resuspended in 50 μL of buffer A. At this step, the first biotinylated di repeat module was bound to the beads and the system was ready for subsequent additions of TALE repeat modules.
Streptavidin Coated Plates
To prepare the streptavidin coated plate for TALE repeat polynucleotides assembly, each streptavidin coated well was washed 3 times with 150 μL of buffer A and then incubated 1 hour in the presence of 100 μL of the SfaNI digested biotinylated first polynucleotidic building block (prediluted to a suitable concentration, see below). Wells were then washed 2 times with 150 μL of buffer B to remove nonspecific binding complexes and finally equilibrated in 150 μL of buffer A. At this step, the first biotinylated polynucleotidic building block was bound to the wells and the system was ready for subsequent additions of TALE repeat polynucleotidic modules.
Assembly of TALE Repeats Polynucleotidic Modules Using a Series of Consecutive Digestion and Ligation Steps
Here, for the sake of clarity, we only described experimental conditions used with streptavidin coated magnetic beads. The experimental conditions used with streptavidin coated plate are essentially the same as the ones described below except for the reaction volume (100 μL instead of 50 μL).
To assemble the 15.5 TALE repeats polynucleotide described in this example (SADE2.3), the 8 first TALE repeats polynucleotide and the 7.5 last TALE repeats polynucleotide (named respectively 8 TALE repeats left, 7.5 TALE repeat right in the
To obtain the 15.5 final TALE repeats polynucleotide, the 7.5 TALE repeats right polynucleotides were first stripped off the beads by BbvI digestion. BbvI digestion mixture contained 3U of BbvI in a final volume of 50 μL of NEB 2 1×. Digestion was allowed to proceed for 1 hour at 37° C. Supernatant was then recovered, column purified using nucleospin extract II kit (Macherey-Nalgen) and finally recovered in a final volume of 35 μL H20. In parallel, the 8 TALE repeats left polynucleotides were digested by SfaNI according to the protocol described above. Beads containing the SfaNI digested 8 TALE repeats left polynucleotides were washed 2 times with 150 μL of buffer B to remove byproducts and enzymes and finally reequilibrated with 150 μL of buffer A. Supernatant was then discarded and a ligation mixture containing 30 μL of BbvI digested 7.5 TALE repeats right polynucleotides, 1 μL of T4 DNA Ligase (3U), in a final volume of 50 μL of Rapid ligation buffer 1× (Promega) was added to the beads. Ligation of TALE repeats Left and Right polynucleotides was allowed to proceed for 1 hour at room temperature and was then stopped by pipetting the ligation mixture out of the beads. Beads were then washed 2 times with 150 μL of buffer B to remove byproducts and enzymes and finally reequilibrated with 150 μL of buffer A. At this stage of the process, the 15.5 TALE repeats polynucleotides were assembled, but still attached to the streptavidin coated beads.
Recovery of TALE Repeats Fragment and Subcloning into pAPG10 Shuttle Vector
Recovery of the 15.5 TALE repeats polynucleotides was performed by SfiI digestion. SfiI digestion mixture containing 20 U SfiI and BSA 1× in a final volume of 100 μL of NEB buffer 4 1×, was added to the beads. The reaction was allowed to proceed for 1 hour at 50° C. Supernatant was recovered, column purified using nucleospin extract II kit (Macherey-Nalgen) and finally recovered in a final volume of 35 μL H20. To subclone the 15.5 TALE repeats polynucleotides into pAPG10, 5 μL of the purified solution was added to 5 μL of Rapid ligation buffer 2× (Promega), 1 μL of SfiI digested pAPG10 cut vector (20 ng) and 1 μL of T4 DNA ligase (3U, Promega). Ligation was allowed to proceed for 1 hour at room temperature. 5 μL of ligated products were then used to transform 30 μL of DH5α chimio competent cells (Invitrogen) according to the manufacturer protocol.
1d—Assembly of TALE Repeats Polynucleotide SADE2.3 (15.5 TALE Repeats Polynucleotide) Using Streptavidin Coated Magnetic Beads as Solid Phase.
The method described above was used to generate a 15.5 TALE repeats polynucleotide that binds to the SADE2.3 homodimeric target sequence (SEQ ID NO: 3) (
1a—Method for Linear Sequential Assembly of TALE Repeat Polynucleotidic Modules Using a Streptavidin Coated Well and Streptavidin Coated Magnetic Beads as Solid Phases.
Below is described an example of 15.5 TALE repeats polynucleotide assembly using building blocks encoding TALE di repeats modules and streptavidin coated plates as a solid phase. This method includes the following steps:
1b—Material and Methods
PCR Amplification and Digestion of TALE Building Blocks
The first TALE building block of TALE repeat polynucleotide was amplified from pAPG10 using TAL_Shuttle_Bio_Forward and TAL_Shuttle_Reverse primers (SEQ ID NO: 29 and 30 respectively). TAL_Shuttle_Bio_Forward contains a biotinylated moiety that binds specifically to the streptavidin coated solid phase. TALE repeat polynucleotidic modules or TALE repeat polynucleotides used for subsequent assembly could be obtained via the method described in section 1a, and could be also obtained by PCR using TAL_Shuttle_short_Forward and TAL_Shuttle_Reverse primers (SEQ ID NO 31 and 30). Conditions for amplification were 5 ng of pAPG10 containing mono or multiple TALE repeat polynucleotidic modules, 250 μM dNTP mix, 200 nM of each oligonucleotide, 1 μL of Herculase II Fusion DNA Polymerase (Agilent) in a final volume of 50 μL of Herculase buffer 1×. PCR was initiated by a 5 min denaturation at 95° C. followed by 30 cycles of 30 sec denaturation at 95° C., 30 sec annealing at 48° C. and 20 sec elongation at 72° C. This was followed by a 3 min elongation at 72° C. PCR products were column purified using nucleospin extract II kit (Macherey-Nalgen), recovered in 40 μL H20 and digested by 10 U of either BbvI or SfaNI (NEB), in NEB 2 and 3 buffers respectively, for 2 hours at 37° C. Digested PCR products were then column purified using the nucleospin extract II kit (Macherey-Nalgen), recovered in 40 μl H2O and quantified using a nanodrop device (Thermo scientific). 2 μg of purified digested PCR products were typically obtained with this process.
Immobilisation of TALE Polynucleotidic Building Blocks on Streptavidin Coated Solid Phase
Two types of streptavidin coated solid phases were used for TALE repeat polynucleotides assembly. These are streptavidin coated magnetic beads (Ademtech) and Streptavidin coated plates (Thermo Scientific). Below are described the methods to immobilize biotinylated DNA on both solid phases.
Streptavidin Coated Magnetic Beads
To prepare the streptavidin coated magnetic beads for TALE repeat polynucleotides assembly, 10 μL of streptavidin magnetic beads (Ademtech, Masterbeads streptavidin, 500 nm, ref #03150) were added to 90 μL PBS 1×, pH7.5 (buffer A) in a 1.5 mL tube (Eppendorff, low binding, DNAase and RNAase free). The mixture was washed 3 times with 100 μL buffer A using the magnet provided by the manufacturer (ref #20105). Beads were then resuspended by pipetting up and down 3 times (off magnet) with 50 μL of biotinylated SfaNI digested di repeat module (prediluted with buffer A to a suitable concentration, see below) and incubated for 30 min at room temperature. The mixture was then placed onto the magnet to remove the supernatant, beads were washed 2 times with 100 μL of PBS 1×, 1M NaCL, pH7.5 (buffer B) to remove nonspecific binding complexes, and then resuspended in 50 μL of buffer A. At this step, the first biotinylated di repeat module was bound to the beads and the system was ready for subsequent additions of TALE repeat modules.
Streptavidin Coated Plates
To prepare the streptavidin coated plate for TALE repeat polynucleotides assembly, each streptavidin coated well was washed 3 times with 150 μL of buffer A and then incubated 1 hour in the presence of 100 μL of the SfaNI digested biotinylated first polynucleotidic building block (prediluted to a suitable concentration, see below). Wells were then washed 2 times with 150 μL of buffer B to remove nonspecific binding complexes and finally equilibrated in 150 μL of buffer A. At this step, the first biotinylated polynucleotidic building block encoding di repeat module was bound to the wells and the system was ready for subsequent additions of TALE repeat polynucleotidic modules.
Assembly of TALE Polynucleotidic Repeats Modules Using a Series of Consecutive Digestion and Ligation Steps
Here, we only described experimental conditions used with streptavidin coated magnetic beads. The experimental conditions used with streptavidin coated plate are essentially the same as the ones described below except for the reaction volume (100 μL instead of 50 μL).
The 15.5 TALE repeats polynucleotide described in this example (SADE2.3) was assembled sequentially in a linear fashion. To do so, 100 ng of biotinylated SfaNI digested first TALE di repeat module, Rvd_b3-biot, was first immobilized on magnetic beads according to the protocol described above. Buffer A was discarded from the beads and ligation with the second TALE di repeat module, the Bbv I digested Rvd_b7, was performed by addition of the ligation mixture. This ligation mixture contained 100 ng of Rvd_b7, 1 μL of T4 DNA ligase (3U, Promega) in a final volume of 50 μL of Rapid ligation buffer 1× (Promega). Ligation was allowed to proceed for 1 hour at room temperature and was then stopped by pipetting the ligation mixture out of the beads. Beads were then washed 2 times with 150 μL of buffer B to remove byproducts and enzymes and finally reequilibrated with 150 μL of buffer A. Supernatant was then discarded from the beads and ligation product containing the TALE quadri repeats polynucleotide Rvd_b3-Rvd_b7 was digested by SfaNI. SfaNI digestion mixture contained 1 U SfaNI in a final volume of 50 μL of NEB 3 1×. Digestion was allowed to proceed for 1 hour at 37° C. and was then stopped by pipetting the digestion mixture out of the beads. Beads were then washed 2 times with 150 μL of buffer B to remove byproducts and enzymes and finally reequilibrated with 150 μL of buffer A. Six additional digestion/ligation steps were performed with Rvd_b11, Rvd_b6, Rvd_b7, Rvd_b12, and Rvd_T4 to get the complete 15.5 TALE repeats polynucleotide. Building block quantities and enzyme units used for repeat assembly are summarized in Table 4.
At this stage of the process, the 15.5 TALE repeats polynucleotides were assembled, but still attached to the streptavidin coated beads.
Recovery of TALE Repeats Fragment and Subcloning into pAPG10 Shuttle Vector
Recovery of the 15.5 TALE repeats polynucleotides was performed by SfiI digestion. SfiI digestion mixture containing 20 U SfiI and BSA 1× in a final volume of 100 μL of NEB buffer 4 1×, was added to the beads. The reaction was allowed to proceed for 1 hour at 50° C. Supernatant was recovered, column purified using nucleospin extract II kit (Macherey-Nalgen) and finally recovered in a final volume of 35 μL H20. To subclone the 15.5 TALE repeats polynucleotides into pAPG10, 5 μL of the purified solution was added to 5 μL of Rapid ligation buffer 2× (Promega), 1 μL of SfiI digested pAPG10 cut vector (20 ng) and 1 μL of T4 DNA ligase (3U, Promega). Ligation was allowed to proceed for 1 hour at room temperature. 5 μL of ligated products were then used to transform 30 μL of DH5α chimio competent cells (Invitrogen) according to the manufacturer protocol.
1d—Assembly of TALE Repeats Polynucleotide SADE2.3 (15.5 TALE Repeats Polynucleotide) Using Streptavidin Coated Plates or Streptavidin Coated Magnetic Beads as a Solid Phase.
The method described above was used to generate a 15.5 TALE repeats TALE repeats polynucleotide that recognizes the homodimeric target SADE2.3 (SEQ ID NO: 3) (
1e—Assembly of AvrBs3 TALE repeats polynucleotides variant (17 TALE repeats polynucleotide) using streptavidin coated plates as a solid phase.
The method described above (section 1a) was used to generate a 17 TALE repeats polynucleotide that recognizes the homodimeric target AvrBs3 (SEQ ID NO: 36) (
As illustrated in
A method to assemble TALE polynucleotidic modules comprised in polynucleotidic building blocks was designed according to the following protocol. It should be noted that each TALE building block may contain multiple TALE repeat modules obtained from previous assemblies. Below is described an assembly example of 3 TALE polynucleotidic modules comprised in building blocks using the dual immobilization procedure. Complete assembly of a TALE DNA binding domain is not described here.
Using reverse elongation on solid phases enables enrichment of the proper nascent TALE repeat polynucleotides and permit high throughput synthesis (HTS) of these molecules. A method to assemble TALE polynucleotidic modules comprised in polynucleotidic building blocks was designed according to the following protocol. Each TALE building block may contain multiple TALE repeat modules obtained from previous assemblies.
Below is described how to prepare TALE building blocks using a reverse elongation procedure.
A TALE building block of TALE repeat polynucleotide was amplified from pAPG10 using TAL_Shuttle_Bio_Forward and TAL_Shuttle_Reverse short primer (SEQ ID NO: 29 and 39, respectively). TAL_Shuttle_Bio_Forward contains a biotinylated moiety that binds specifically to the streptavidin coated solid phase. The last TALE repeat polynucleotidic modules or TALE repeat polynucleotides used for subsequent assembly could be obtained via the method described in example 1, section 1a, and could be also obtained by PCR using TAL_Shuttle_short_Forward and TAL_Shuttle_Reverse primers (SEQ ID NO 31 and 30). Conditions for amplification were 5 ng of pAPG10 containing mono or multiple TALE repeat polynucleotidic modules, 250 μM dNTP mix, 200 nM of each oligonucleotide, 1 μL of Herculase II Fusion DNA Polymerase (Agilent) in a final volume of 50 μL of Herculase buffer 1×. PCR was initiated by a 5 minutes denaturation at 95° C. followed by 30 cycles of 30 sec. denaturation at 95° C., 30 sec. annealing at 48° C. and 30-45 sec. elongation at 72° C. This was followed by a 3 min. elongation at 72° C. PCR products were column purified using nucleospin extract II kit (Macherey-Nalgen), recovered in 40 μL H2O and digested by 10 U of either BbvI or SfaNI (NEB), in Fast digest buffers for 1 hour at 37° C. Digested PCR products were then column purified using the nucleospin extract II kit (Macherey-Nalgen), recovered in 40 μL H2O and quantified using a nanodrop device (Thermo scientific). 1-2 μg of purified digested PCR products were typically obtained with this process by PCR.
As illustrated in
The following example is given for the synthesis of a 13.5 blocks polynucleotidic module, using tri-modules (A, B, C, D) and a terminal di-module (1.5 RVDs) (E), but can be adapted to the synthesis of any repeat polynucleotides using various starting modules (Prior to any assembly of polynucleotidic modules, the solid surfaces (streptavidin-coated wells) are prepared by two washing steps with 200 μl of PBS 1×):
It is understood that washing steps can be done respectively after a given immobilization step of a polynucleotides modules or blocks, according to the state of the art; as a non-limiting example, three washing steps of an appropriate volume of saline buffer, such as PBS, can be added after a given immobilization step.
Analyses by PCR screening (
In addition the following steps 17, 18 and 19 can be added after steps 1, 5, 9 and/or 13 to combine advantages of both, reverse elongation and direct linear sequential synthesis.
The case where steps 17, 18 and 19 are added after steps 5 is represented in
It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.
(TALE) hybrid nuclease with novel DNA binding specificity creates double-strand breaks.” Proc Natl Acad Sci USA 108(6): 2623-8.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2012/001861 | 7/20/2012 | WO | 00 | 5/7/2014 |
| Number | Date | Country | |
|---|---|---|---|
| 61513471 | Jul 2011 | US | |
| 61579494 | Dec 2011 | US |
