Patent Application
20240248080
A Sequence Listing in XML format is incorporated by reference into the specification. The name of the XML file containing the Sequence Listing is SeqList.xml. The XML file is 342,331 bytes and was created and submitted electronically via EFS-Web on Apr. 8, 2024.
Kaposi Sarcoma Associated Herpesvirus (KSHV) is a medically important virus with infection found globally. It is the causative agent for Kaposi sarcoma (KS), one of the AIDS defining complications. Furthermore, KSHV causes two other human diseases, primary effusion lymphoma and multicentric Castleman's disease. This virus infects many cell types including endothelial cells and B cells. Currently there are no drugs available to eliminate KSHV latent infection. Once infected with KSHV, the individual is infected for life. No vaccines against KSHV infection are currently available. There are urgent needs for developing drugs and vaccines for treatment and prevention of KSHV infection and KSHV-associated diseases including KS.
The invention provides Kaposi sarcoma associated herpesvirus (KSHV) relevant methods and compositions, including antivirals, vaccines, and vectors.
The invention provides novel antiviral targets and gene function methods resulting from our comprehensive analysis of KSHV, and KSHV opportunistic factors with dual functions of regulating both the immune environment/responses and viral reactivation/replication. These viral factors that serve dual roles represent a novel strategy of achieving pathogen opportunistic pathogenesis, and have implications for the entire field of infectious diseases.
The disclosed, systematic analysis of the KSHV genome represents the most extensive global characterization of this virus. The results from this study, such as the identification of 44 viral ORFs essential for viral replication and the characterization of 47 growth-dispensable viral genes, enable new strategies and novel approaches for treatment and prevention of KSHV as well as other herpesviruses.
We disclose that KSHV encodes genes that have dual functions of regulating viral reactivation/replication and modulating host immune environment/response. We identified viral mutants with inactivation in genes that exhibit enhanced or reduced reactivation/lytic replication phenotypes as compared to the wild type virus. These inactivated ORFs with immunomodulatory functions encode factors that regulate viral reactivation and replication in connection with the host immune environment/status and responses. These ORFs are examples of virally encoded components that facilitate pathogen opportunistic activities and responses. In addition to KSHV, pathogen opportunistic responses may be a strategy employed by other infectious agents to enhance their long-term survivability within their respective host population.
The invention provides methods for developing drugs mimicking or activating opportunistic factors that inhibit viral reactivation/replication and enhance host immune responses may lead to effective therapies against infectious diseases. Similar antiviral effects can also be achieved by developing compounds that block or inactivate opportunistic factors that enhance viral reactivation/replication and suppress host immune responses. In vitro hyper-growth strains can be used for facile production of large quantity of subunit and attenuated live vaccines.
In aspects and embodiments the invention provides:
In aspects and embodiments the invention provides:
Methods of using the mutant viruses of claim 1 in applications such as research (e.g. for analyzing the molecular, cellular, and immunological response to mutant virus infections), and industry (e.g. as a “helper-virus” in the production of other viral vectors, and/or the generation of live-attenuated vaccines.
Methods of mutagenesis having high fidelity (e.g. insert or remove a desired sequence with single nucleotide resolution), superior to other mutagenesis approaches like CRISPR.
Methods for reconstituting mutant viruses (e.g. using transfection, induction and tittering) comprising a tractable workflow.
The identification of genetic sequences that are essential for viral reproduction, and their insertion into artificial constructs (e.g. protein expression plasmids).
Methods and reagents for high throughput, in-vitro drug screening assays to identify novel antivirals for KSHV, and other human herpesviruses, based hereon.
Development of other therapeutic approaches including monoclonal antibodies and nucleic acid therapies for KSHV infection.
KSHV provides many useful features for vector development including its low seroprevalence in the developed world (which circumvents the pre-existing immunity problem encountered with adeno-associated virus (AAV) vectors), its ability to accommodate large transgene payloads (up to 50 kb in KSHV compared to 5 kb in current AAV approaches), and the absence of viral integration into the host genome.
Non-essential genes that impart severely attenuated growth, and thus their growth properties provide advantageous live-attenuated vaccine candidates.
Growth properties of non-attenuated mutants indicate genome regions that can be modified to contain foreign transgenes without affecting the growth properties of the virus in-vitro. These regions are useful in the development of KSHV-based vectors as their disruption/replacement will not affect viral growth during the manufacturing process. The growth properties of viral mutants under different conditions is also useful for identifying viral factors that regulate viral reactivation. These properties provision novel therapies for KSHV; for example, drugs targeting regulators of reactivation can be used to enhance reactivation and stimulate host-mediated immune clearance of latent virus infection, or, the repress viral reactivation to eliminate persistent infection.
Screening results provide valuable assessments of the efficacy and safety of therapeutics targeting KSHV infected cells, as well as KSHV vaccines and KSHV based vectors.
Use and expression of these opportunistic viral immunomodulatory factors for KSHV therapy; for example, over-expressing an opportunistic factor that functions to suppress KSHV spontaneous reactivation, find use in the treatment of KSHV infection. 7. Use of opportunistic factors of KSHV and all other animal viruses that have dual functions as both the modulators of immune environment/response and regulators of viral reactivation/replication, as disclosed.
The invention encompasses all combinations of the particular embodiments recited herein, as if each combination had been laboriously recited.
Unless contraindicated or noted otherwise, in these descriptions and throughout this specification, the terms “a” and “an” mean one or more, the term “or” means and/or. It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein, including citations therein, are hereby incorporated by reference in their entirety for all purposes.
Using a bacterial artificial chromosome (BAC) engineering and RED recombinase technology in conjunction with growth curve analysis in human cells in tissue culture, a viral mutant library with inactivation of each of 91 open reading frames spanning the entire KSHV genome was constructed. The BAC based ORF inactivation constructs were then transfected into human cells in tissue culture. Constructs with inactivation in 44 separate and distinct ORFs in the KSHV genome did not yield any viral progeny upon transfection into the human cells with induction, indicating that those regions of the genome are essential for viral growth and progeny production. This effort represents an exhaustive and complete mapping of the viral genome to identify all regions essential for viral growth and progeny production. These identified essential genes represent potential drug targets for anti KSHV therapeutic applications. In addition, the functional mapping of the genome has identified regions in the viral genome dispensable for viral growth and progeny production. All ORF inactivation constructs that yielded viral progeny upon transfection and induction were deemed dispensable for viral growth. Growth curve analyses were performed on the BAC derived mutant virus and the inactivated ORF categorized as either severe growth attenuation, moderate growth attenuation, no growth attenuation, or enhanced growth.
The identification of these non-essential genes distinguishes which genes can be inactivated or deleted to create an attenuated virus for use as a vaccine, or which genes can be inactivated or deleted to create a gene therapy vector so as to accommodate the delivery gene of interest without affecting viral propagation in vitro. Further growth kinetic characterization of the constructed mutants was carried out on different human cells such as human B cells and human microvascular endothelial cells and compared to the results from the human iSLK cell and 293T cell characterization. This comparative analysis identified ORF inactivation viruses that reactivated and replicated differentially, compared to the wild-type virus, in the cell types tested, indicating that these open reading frames encoded cell tropism important factors
Kaposi's sarcoma-associated herpesvirus (KSHV) is an opportunistic pathogen causing Kaposi's sarcoma. It is capable of establishing latent infection, which can be reactivated to engage lytic infection for progeny production. KSHV contains a ˜165 kilobase DNA genome predicted to encode at least 90 open reading frames (ORFs). In this report, we generated 91 KSHV mutants, each characterized by the disruption of a single viral ORE. The growth of these mutants in cultured cells was examined to systematically investigate the necessity of each ORF for viral latency, reactivation, and lytic replication. Salient aspects are (a) 44 ORFs are essential for viral lytic replication in cultured cells and 47 are nonessential; (b) KSHV reactivation can be positively or negatively regulated by specific viral ORFs; and (c) ORFs identified to regulate viral reactivation encode functions modulating both innate and adaptive immune responses. The intersection of viral immunomodulatory genes controlling reactivation suggests that KSHV engages in a concerted effort to communicate and respond to the host immune system for reactivation and replication using a viral sensory network. Our results imply a novel mechanism in which reactivation of KSHV is actively controlled by the virus in response to its surrounding environment, leading to the opportunistic nature of viral diseases that are strongly correlated to the host's immune status and conditions.
Kaposi's sarcoma associated herpesvirus (KSHV) is an oncogenic gamma-herpesvirus which causes Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease1. The other members of the human herpesvirus family include herpes simplex virus (HSV) 1 and 2, varicella zoster virus (VZV), Epstein Barr virus (EBV), cytomegalovirus (CMV), and human herpesviruses 6 and 72. A hallmark of herpesvirus infection is life-long persistence in a latent state with episodes of reactivation and lytic replication that correlate with the host's immune status and disease progression. During latency, herpesvirus genomes reside as episomes in the nucleus and only a few viral genes are expressed2. Onset of reactivation from latency can occur in the presence of certain stimuli and is associated with changes in the host immune status. KSHV reactivation triggers viral lytic replication which proceeds via a highly regulated temporal cascade of gene expression, resulting in viral DNA replication and the assembly and release of infectious virions from the cell1.
Reactivation and lytic replication of KSHV play important roles in the development of KSHV-associated disease as mechanisms for infection of naïve cells, through oncogenic effects of certain lytic proteins and paracrine signaling1. However, the roles of individual viral genes in reactivation and lytic replication are not fully elucidated. Also, little is known about the processes and factors linking KSHV reactivation and changes in the host immune status.
Global studies assaying the essentiality of viral genes in several herpesviruses have been reported but were limited to studying lytic replication and not reactivation or latency3-7. KSHV consists of a ˜165 kb genome that has been predicted to encode at least 90 open reading frames (ORFs) including small and upstream ORFs, and numerous non-coding RNAs including miRNAs and circRNAs8-14. Only a handful of KSHV ORFs have been studied using gene inactivation mutants15-42.
In this report, we performed genome-wide mutational analysis and constructed 91 ORF-inactivating mutants using the KSHV BAC16 construct. BAC16 contains a KSHV genome cloned as a bacterial artificial chromosome (BAC)38. Resembling KSHV infection in vivo, virus infection from the BAC16 construct in human iSLK cells typically leads to latency, and reactivation and lytic replication from this system can be induced43. We studied ORF-inactivating mutants and investigated the roles of viral ORFs in KSHV latency, reactivation, and lytic replication. Notably, our study is the first global functional profiling of a KSHV genome.
To generate mutant viruses, previous studies used a 2-step red-mediated recombination with BAC16 followed by transfection into iSLK cells, establishment of transfected cell populations, and induction of lytic replication15-40. We used this approach to construct 91 BAC16 mutants. Each mutant has an inactivating mutation in a single ORF consisting of either a complete ORF deletion (nonoverlapping ORFs) or an insertion of a stop codon in each frame in the ORF 5′ region (overlapping ORFs). Mutant BAC16 DNAs were screened by PCR with primers (Table S1) designed to produce a unique and recognizable product (e.g. a ˜300 bp PCR product for ΔORF62) (
To reconstitute virus, iSLK cells were transfected with mutant or parental BAC16 DNAs and selected with hygromycin B. This produced populations of GFP+ cells as BAC16 contained a GFP expression cassette. To confirm KSHV infection, we also examined the expression of ORF73-encoded latency associated nuclear antigen (LANA) (
Lytic replication was induced in transfected cell lines by doxycycline and sodium butyrate treatment and the supernatants were harvested 96 hours post-induction and titered on 293T cells (
The majority of the 44 essential ORFs identified are conserved among herpesviruses with key roles in virus production, such as structural, enzymatic, and regulatory functions (
The growth of mutants with inactivation of nonessential ORFs was further analyzed under multi-step growth conditions for 19 days (
To assay virus generated from reactivation and subsequent lytic replication, we infected iSLK cells, induced reactivation at 2 days post-infection (dpi), and harvested the supernatants at 5 dpi for titration. At 2 dpi prior to induction, we barely detected virus from the supernatant collected from BAC16-infected cells, suggesting establishment of viral latency and lack of reactivation. This conclusion is consistent with our observations that the percentage of parental BAC16-infected cells expressing ORF45 (an immediate early gene), K8 (an early gene), or K8.1 (a late gene) was 1.24%, 0.61%, and 0.33% respectively, suggesting that over 98% of BAC16-infected cells were not undergoing lytic replication (Table S4).
We expected to observe changes in virus production due to deficiencies or enhancements in reactivation or subsequent lytic replication. Most mutants generated a titer within 10-fold of parental BAC16 (
Increased virus production possibly results from enhanced lytic antigen expression. To test this hypothesis, we measured the expression of viral ORFs 45, K8 and K8.1 proteins under the same conditions. Mutants ΔORFK3 and ΔORFK5 showed an increased percentage of lytic antigen-expressing cells relative to parental BAC16 (
Next, we took advantage of our unique system to identify viral ORFs regulating latency and spontaneous reactivation by measuring virus production in the absence of lytic induction. At 6 dpi, the percentage of parental BAC16-infected cells expressing ORF45, K8, or K8.1 was 0.31%, 0.25%, 0.09% respectively, suggesting establishment of latency and lack of reactivation and lytic replication in over 99.5% of infected cells (Table S4). Thus, any change in virus production probably results from alteration of latency and spontaneous reactivation due to the inactivation of the ORF in the mutant.
Consistent with previous observations that ORF50 is necessary and sufficient for reactivation 4748, ΔORF50 showed a 30-fold decrease in virus production relative to parental BAC16 (
Several mutants (e.g. ΔORF11AA, ΔORF72, ΔORFK3, ΔORFK6, and ΔORFK7) achieved enhanced virus production (
We then measured the percentage of infected cells expressing ORF45, K8, or K8.1 under these conditions to understand the correlation between viral lytic gene expression and altered levels of reactivation and virus production (
This is the first genome-wide study to identify viral genes important for KSHV latency, reactivation, and lytic replication. We found that 44 ORFs are essential for successful completion of the viral life cycle. Of these, 33 ORFs are conserved in all herpesvirus subfamilies, six (ORF10, 18, 24, 30, 31, and 66) are conserved among beta and gamma herpesviruses, and five (ORF45, 50, 52, 73, and 75) are gamma herpesvirus-specific2,52. Surprisingly, 10 ORFs conserved in all herpesvirus subfamilies were found to be nonessential in KSHV (Table 1), despite some of them being essential in other herpesviruses tested (Table S3)2,3,53. These 10 KSHV ORFs, which homologues are essential for the replication of other herpesviruses, may be complemented or substituted by the functions of other KSHV ORFs or cellular genes.
Our profiling results show that reactivation is regulated positively or negatively by two specific sets of viral genes, which may act as important parts of the latent/lytic switch. For example, some ORFs may repress spontaneous (e.g. ORFs 11AA, 72, and K6) or induced reactivation (e.g. K3 and K5) while others (e.g. ORFK11) enhance spontaneous reactivation (
As an opportunistic pathogen, the onset of KSHV lytic replication and its associated diseases correlate with the host's immune status. One hypothesis is that KSHV engages in random spontaneous reactivation to achieve persistent infection and the host immune responses are responsible for controlling the level of reactivation. However, under immunodeficient conditions, viral reactivation is left unchecked and takes off to full blown lytic replication, leading to KSHV diseases. An alternative hypothesis is that KSHV reactivation is not random but tightly and actively regulated by viral factors, which connect reactivation with the host immune status. It is conceivable that these factors, which regulate reactivation, are involved in sensing, interacting, and modulating immune responses.
The alternative hypothesis is supported by our results. Six ORFs (i.e. K3, K4, K5, K6, K7, and KI 1) known to have immunomodulatory functions were found to promote or suppress virus reactivation and production (Table 1,
K4 and K6 encode viral chemokine homologues49,58. K3 and K5 modulate expression of surface glycoproteins important for immune responses such as MHC and interferon-γ receptor45,46,59. K7 and K11 are anti-apoptotic factors involved in autophagy and IFN transcription responses, respectively51,60,61. These KSHV factors can play a role in modulating the immune-microenvironment, cell membrane receptor composition, and appropriate downstream signaling pathways to produce an immune-switch for KSHV latency and reactivation. The virally reconfigured pathways serve as a sensory network that allows KSHV to communicate with, and deliberately respond to, changes in host homeostasis. In the presence of immuno-selective/repressive pressure, these virally reconstructed pathways promote latency, however, under immunocompromised conditions, these pathways promote lytic replication and progeny production.
All annotated KSHV ORFs in the GenBank sequence (accession #GQ994935.1) were selected for mutagenesis, as well as several recently discovered upstream ORFs (uORF)9. The BAC mutants were derived from the BAC16 construct using the 2-step RED-mediated recombination methods as described previously 38. For non-overlapping ORFs, the entire ORF from the start to stop codon was deleted from BAC16. For overlapping ORFs, a stop codon sequence (5′-TAGGTAGATAGG-3′) was inserted in a non-overlapping region, downstream of the annotated start codon. The rescued virus was derived from the mutant BAC DNA by restoring the wildtype sequence to the deleted or stop codon-inserted ORF, using the previously described RED-mediated recombination methods38.
The BAC DNAs of the mutants were screened by restriction digest using NheI (Thermo Fisher Scientific, MA, Waltham) to examine the overall BAC genomic structure, and PCR using primers flanking the ORF for the presence of the mutations. The digested and PCR products were separated on agarose gels and visualized on a ChemiDoc Touch apparatus (Bio-Rad Laboratories, CA, Hercules). Sequencing analysis (UC-Berkeley DNA core sequencing facility) also confirmed the stop codon mutations. The primers used for construction and screening of the mutants and rescued viruses are listed in Table S1 and S2.
KSHV (BAC16), human iSLK cells, and human 293T cells (ATCC, VA, Manassas) were propagated as described previously38,43. Specifically, iSLK cells were maintained in normal/uninduced media, which is Dulbecco's modified eagle's medium (DMEM) with sodium pyruvate and glutamine (Thermo Fisher Scientific, MA, Waltham) supplemented with 10% HI FBS (Cytiva, MA, Marlborough) and 1% Penicillin/Streptomycin (Thermo Fisher Scientific, MA, Waltham). The selection media is DMEM with sodium pyruvate and glutamine supplemented with 10% HI FBS and 1.2 mg/ml hygromycin B (Thermo Fisher Scientific, MA, Waltham). The induction media is DMEM with sodium pyruvate and glutamine supplemented with 10% HI FBS, 1% Penicillin/Streptomycin, 1 ug/ml doxycycline, and 1 mM sodium butyrate.
BAC DNAs of the mutants were purified using the NucleoBond BAC100 kit (Macherey-Nagel, Germany, Düren) following the manufacturer's instructions, and were used for transfection experiments. Naïve iSLK cells were seeded into 6-well plates at 70-90% confluence (approximately 3.0×105 cells/well), incubated overnight, and then transfected with BAC DNAs (˜2.5 ug/well), using lipofectamine 2000 (Thermo Fisher Scientific, MA, Waltham) following the manufacturer's instructions. At 48 hours post transfection, cells were incubated and expanded in the media containing hygromycin B (1.2 mg/ml). No colony isolations were performed. Cells were monitored by phase and fluorescence microscopy on a Nikon TE300 microscope (Nikon, Japan, Tokyo).
Cells containing the mutant and parental BAC16 DNAs (˜1.7×107 cells) were seeded and then incubated in induction media (DMEM with sodium pyruvate and glutamine supplemented with 10% HI FBS, 1% Penicillin/Streptomycin, 1 ug/ml doxycycline, and 1 mM sodium butyrate) to induce KSHV to reactivate and enter the lytic cycle. At different times post induction, the supernatants were harvested, spun (3,200×g) at 4° C. for 15 minutes, filtered through a 0.45 uM filter (Thermo Scientific Nalgene, MA, Waltham), and concentrated by centrifugation (SureSpin 630 rotor, 13,000 rpm) at 4° C. for 3 hours. The pellet was resuspended in DMEM and stored at −80° C.
Titration of virus stocks was conducted using 293T cells, following procedures described previously62. Briefly, 293T cells seeded in 48-well plates (˜5×104 cells/well) were infected with serial dilutions of virus stocks and then incubated in induction media. After 48 hours the infected cells were examined by fluorescence microscopy using a Nikon TE300 microscope (Nikon, Japan, Tokyo).
The samples with appropriate dilution that contained appropriately 2-20% of GFP+ cells were selected for FACS. Cells were resuspended in 750 ul of “FACS wash buffer” (Dulbecco's phosphate-buffered saline (DPBS) (Thermo Fisher Scientific, MA, Waltham) containing 0.1% w/v BSA (Sigma, MO, St. Louis)) and then fixed in DPBS containing 1% paraformaldehyde (Electron Microscopy Sciences, PA, Hatfield) for 5 minutes at room temperature. The fixed cells were subjected to FACS analysis with a BD-Fortessa X20 cytometer (Becton, Dickinson, NJ, Franklin Lakes). When a mutant cell line yielded no titer, or a very low titer compared to BAC16 cell line, at least two additional independent DNA preparations and transfection were performed to verify the growth phenotype of the mutants. No viral progeny was detected from mutant DNAs containing mutations in essential genes.
Growth analyses were performed with iSLK cells in 96-well plates. Virus growth was analyzed under three culture conditions. First, under the multi-step growth condition, iSLK cells (˜2.5×104 cells total) were infected with mutants under a multiplicity of infection (MOI) of 0.1, and maintained in induction media (DMEM with sodium pyruvate and glutamine supplemented with 10% HI FBS, 1% Penicillin/Streptomycin, 1 ug/ml doxycycline, and 1 mM sodium butyrate). Supernatants were harvested at 1, 4, 7, 10, 13, 16, and 19 day post-infection (dpi). Second, under the induced reactivation condition, iSLK cells (˜2.5×104 cells total) were infected with mutants (MOI=1). At 2 dpi, cells were incubated in the induction media and supernatants were harvested at 5 dpi. Third, under the spontaneous reactivation condition, iSLK cells (˜2.5×104 cells total) were infected with mutants (MOI=1) and maintained in the normal/uninduced media in the absence of doxycycline and sodium butyrate. Supernatants were harvested at 6 dpi. The supernatants were transferred to new 96-well plates and stored at −80° C. until tittering. Tittering of the supernatants was done as outlined above to determine virus growth at different timepoints. Each analysis was repeated three times and each sample time-point was done in triplicate.
Mutant and parental BAC16 cell lines were seeded onto coverslips (Corning, NY, Corning) placed in 24-well plates. Cells were either maintained in normal/uninduced media (DMEM with sodium pyruvate and glutamine supplemented with 10% HI FBS, 1% Penicillin/Streptomycin) or induction media (DMEM with sodium pyruvate and glutamine supplemented with 10% HI FBS, 1% Pen Strep, 1 ug/ml doxycycline, and 1 mM sodium butyrate) for 72 hours. Cells were fixed with 4% paraformaldehyde (Electron Microscopy Sciences, PA, Hatfield). Fixed cells were permeabilized with 0.2% Triton X-100 (Sigma, MO, St. Louis) for 10 minutes followed by three 5-minute washes in PBST (DPBS containing 0.1% tween-20 (Sigma, MO, St. Louis)) and a 1-hour incubation in PBST with 5% goat serum (Abcam, UK, Cambridge). Cells were incubated with PBST containing 5% goat serum and anti-LANA antibody (Advanced Biotechnologies, MD, Columbia) followed by incubation with PBST containing 5% goat serum and anti-rat secondary antibody (Life Technologies, CA, Carlsbad). Cells were then incubated with PBST containing 1 ug/ml DAPI (Thermo Fisher Scientific, MA, Waltham) at room temperature, mounted on slides using Fluoromount G (Sigma, MO, St. Louis), and imaged on a Nikon TE300 microscope.
iSLK cells were trypsinized (Thermo Fisher Scientific, MA, Waltham) and collected by centrifugation at 300×g for 5 minutes at 4° C. Cells were fixed in 4% paraformaldehyde for 5 minutes at room temperature and stored at 4° C. Fixed cells were permeabilized with 0.1% Triton X-100 (Sigma, MO, St. Louis) for 10 minutes at room temperature and blocked for 15 minutes in blocking buffer (DPBS supplemented with 0.5% BSA (Sigma, MO, St. Louis), 0.05% Tween-20 (Sigma, MO, St. Louis), and 5% goat serum (Abcam, UK, Cambridge)). Primary antibody incubation was conducted for 30 minutes with anti-LANA (Advanced Biotechnologies, MD, Columbia), anti-ORF45 (Thermo Fisher Scientific, MA, Waltham), anti-K8 (Promab Biotechnologies, CA, Richmond) or anti-K8.1 (Santa Cruz Biotechnology, TX, Dallas) in blocking buffer. Secondary antibody incubation was conducted for 30-minutes with goat anti-mouse IgG AlexaFluor647 or goat anti-rat IgG AlexaFluor568 (Life Technologies, CA, Carlsbad) in blocking buffer. Cells were analyzed using a BD LSR Fortessa X-20 flow cytometer (Becton Dickinson, Franklin Lakes, NJ) and flowing Software 2.
#BALF3120
#BVRF2123, 124
BDLF3.5
UL51
UL43
M9/ORF65*
†Indicates that the ORF's essentiality was assessed as a double mutant.
#Indicates essentiality was inferred from knockdown studies.
‡Indicates two or more studies disagree on essentiality.
This application is a continuation of PCT/US22/47515, filed Oct. 24, 2022, which claims priority to U.S. Provisional Application No. 63/271,704 filed Oct. 25, 2021, the disclosures of which are hereby incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63271704 | Oct 2021 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US22/47515 | Oct 2022 | WO |
| Child | 18629922 | US |
