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Wang TY, Meng FD, Sang GJ, Zhang HL, Tian ZJ, Zheng H, Cai XH, Tang YD. A novel viral vaccine platform based on engineered transfer RNA. Emerg Microbes Infect 2023; 12:2157339. [PMID: 36482724 PMCID: PMC9769134 DOI: 10.1080/22221751.2022.2157339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In recent years, an increasing number of emerging and remerging virus outbreaks have occurred and the rapid development of vaccines against these viruses has been crucial. Controlling the replication of premature termination codon (PTC)-containing viruses is a promising approach to generate live but replication-defective viruses that can be used for potent vaccines. Here, we used anticodon-engineered transfer RNAs (ACE-tRNAs) as powerful precision switches to control the replication of PTC-containing viruses. We showed that ACE-tRNAs display higher potency of reading through PTCs than genetic code expansion (GCE) technology. Interestingly, ACE-tRNA has a site preference that may influence its read-through efficacy. We further attempted to use ACE-tRNAs as a novel viral vaccine platform. Using a human immunodeficiency virus type 1 (HIV-1) pseudotyped virus as an RNA virus model, we found that ACE-tRNAs display high potency for read-through viral PTCs and precisely control their production. Pseudorabies virus (PRV), a herpesvirus, was used as a DNA virus model. We found that ACE-tRNAs display high potency for reading through viral PTCs and precisely controlling PTC-containing virus replication. In addition, PTC-engineered PRV completely attenuated and lost virulence in mice in vivo, and immunization with PRV containing a PTC elicited a robust immune response and provided complete protection against wild-type PRV challenge. Overall, replication-controllable PTC-containing viruses based on ACE-tRNAs provide a new strategy to rapidly attenuate virus infection and prime robust immune responses. This technology can be used as a platform for rapidly developing viral vaccines in the future.
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Affiliation(s)
- Tong-Yun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China,Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, People's Republic of China
| | - Fan-Dan Meng
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China,Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, People's Republic of China
| | - Guo-Ju Sang
- Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, People's Republic of China
| | - Hong-Liang Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Zhi-Jun Tian
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China
| | - Hao Zheng
- Shanghai Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China,Hao Zheng Shanghai Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Shanghai150001, People’s Republic of China
| | - Xue-Hui Cai
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China,Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, People's Republic of China,Heilongjiang Provincial Research Center for Veterinary Biomedicine, Harbin, People's Republic of China,Xue-Hui Cai State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, People’s Republic of China; Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin150001, People’s Republic of China
| | - Yan-Dong Tang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, People’s Republic of China,Heilongjiang Provincial Key Laboratory of Veterinary Immunology, Harbin, People's Republic of China, Yan-Dong Tang
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Generation of Premature Termination Codon (PTC)-Harboring Pseudorabies Virus (PRV) via Genetic Code Expansion Technology. Viruses 2022; 14:v14030572. [PMID: 35336979 PMCID: PMC8950157 DOI: 10.3390/v14030572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 02/28/2022] [Accepted: 03/09/2022] [Indexed: 12/27/2022] Open
Abstract
Despite many efforts and diverse approaches, developing an effective herpesvirus vaccine remains a great challenge. Traditional inactivated and live-attenuated vaccines always raise efficacy or safety concerns. This study used Pseudorabies virus (PRV), a swine herpes virus, as a model. We attempted to develop a live but replication-incompetent PRV by genetic code expansion (GCE) technology. Premature termination codon (PTC) harboring PRV was successfully rescued in the presence of orthogonal system MbpylRS/tRNAPyl pair and unnatural amino acids (UAA). However, UAA incorporating efficacy seemed extremely low in our engineered PRV PTC virus. Furthermore, we failed to establish a stable transgenic cell line containing orthogonal translation machinery for PTC virus replication, and we demonstrated that orthogonal tRNAPyl is a key limiting factor. This study is the first to demonstrate that orthogonal translation system-mediated amber codon suppression strategy could precisely control PRV-PTC engineered virus replication. To our knowledge, this is the first reported PTC herpesvirus generated by GCE technology. Our work provides a proof-of-concept for generating UAAs-controlled PRV-PTC virus, which can be used as a safe and effective vaccine.
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Yan S, Huang B, Bai X, Zhou Y, Guo L, Wang T, Shan Y, Wang Y, Tan F, Tian K. Construction and Immunogenicity of a Recombinant Pseudorabies Virus Variant With TK/gI/gE/11k/28k Deletion. Front Vet Sci 2022; 8:797611. [PMID: 35146013 PMCID: PMC8821880 DOI: 10.3389/fvets.2021.797611] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/13/2021] [Indexed: 12/03/2022] Open
Abstract
In China, the re-emerging pseudorabies virus (PRV) variant has caused large-scale outbreaks of pseudorabies in swine herds with classical PRV vaccine immunization since late 2011. Here, a recombinant PRV with TK/gI/gE/11k/28k deletion was constructed based on variant HN1201 strain isolated in 2012, by the bacterial artificial chromosome infectious clones. Compared with the parental virus, the recombinant PRV rHN1201TK−/gE−/gI−/11k−/28k− showed a similar virus grown curve and exhibited smaller plaques. The vaccination of rHN1201TK−/gE−/gI−/11k−/28k− could elicit an earlier and higher level of gB antibody, and the neutralizing antibodies elicited by rHN1201TK−/gE−/gI−/11k−/28k− were effective against both PRV classical and variant strains. Clinically, the body temperature of the pigs immunized with rHN1201TK−/gE−/gI−/11k−/28k− was significantly lower than that of the classical PRV vaccine immunized pigs, and the recombinant PRV could provide effective protection against the challenge with the PRV variant. These results imply that the rHN1201TK−/gE−/gI−/11k−/28k− could be a promising vaccine candidate for the prevention of the current epidemic of pseudorabies in China.
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Ren CZ, Hu WY, Zhang JW, Wei YY, Yu ML, Hu TJ. Establishment of inflammatory model induced by Pseudorabies virus infection in mice. J Vet Sci 2021; 22:e20. [PMID: 33774936 PMCID: PMC8007442 DOI: 10.4142/jvs.2021.22.e20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/18/2020] [Accepted: 01/07/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Pseudorabies virus (PRV) infection leads to high mortality in swine. Despite extensive efforts, effective treatments against PRV infection are limited. Furthermore, the inflammatory response induced by PRV strain GXLB-2013 is unclear. OBJECTIVES Our study aimed to investigate the inflammatory response induced by PRV strain GXLB-2013, establish an inflammation model to elucidate the pathogenesis of PRV infection further, and develop effective drugs against PRV infection. METHODS Kunming mice were infected intramuscularly with medium, LPS, and different doses of PRV-GXLB-2013. Viral spread and histopathological damage to brain, spleen, and lung were determined at 7 days post-infection (dpi). Immune organ indices, levels of reactive oxygen species (ROS), nitric oxide (NO), and inflammatory cytokines, as well as levels of activity of COX-2 and iNOS were determined at 4, 7, and 14 dpi. RESULTS At 10⁵-10⁶ TCID50 PRV produced obviously neurological symptoms and 100% mortality in mice. Viral antigens were detectable in kidney, heart, lung, liver, spleen, and brain. In addition, inflammatory injuries were apparent in brain, spleen, and lung of PRV-infected mice. Moreover, PRV induced increases in immune organ indices, ROS and NO levels, activity of COX-2 and iNOS, and the content of key pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon-γ and MCP-1. Among the tested doses, 10² TCID50 of PRV produced a significant inflammatory mediator increase. CONCLUSIONS An inflammatory model induced by PRV infection was established in mice, and 10² TCID50 PRV was considered as the best concentration for the establishment of the model.
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Affiliation(s)
- Chun Zhi Ren
- College of Animal Science and Technology, Guangxi University, Nanning 530004, PR China.,Guangxi Agricultural Vocational College, Nanning 530007, PR China
| | - Wen Yue Hu
- School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, PR China
| | - Jin Wu Zhang
- College of Animal Science and Technology, Guangxi University, Nanning 530004, PR China
| | - Ying Yi Wei
- College of Animal Science and Technology, Guangxi University, Nanning 530004, PR China
| | - Mei Ling Yu
- College of Animal Science and Technology, Guangxi University, Nanning 530004, PR China.
| | - Ting Jun Hu
- College of Animal Science and Technology, Guangxi University, Nanning 530004, PR China.
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Fu PF, Cheng X, Su BQ, Duan LF, Wang CR, Niu XR, Wang J, Yang GY, Chu BB. CRISPR/Cas9-based generation of a recombinant double-reporter pseudorabies virus and its characterization in vitro and in vivo. Vet Res 2021; 52:95. [PMID: 34174954 PMCID: PMC8233574 DOI: 10.1186/s13567-021-00964-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/27/2021] [Indexed: 11/24/2022] Open
Abstract
Pseudorabies, caused by pseudorabies virus (PRV) variants, has broken out among commercial PRV vaccine-immunized swine herds and resulted in major economic losses to the pig industry in China since late 2011. However, the mechanism of virulence enhancement of variant PRV is currently unclear. Here, a recombinant PRV (rPRV HN1201-EGFP-Luc) with stable expression of enhanced green fluorescent protein (EGFP) and firefly luciferase as a double reporter virus was constructed on the basis of the PRV variant HN1201 through CRISPR/Cas9 gene-editing technology coupled with two sgRNAs. The biological characteristics of the recombinant virus and its lethality to mice were similar to those of the parental strain and displayed a stable viral titre and luciferase activity through 20 passages. Moreover, bioluminescence signals were detected in mice at 12 h after rPRV HN1201-EGFP-Luc infection. Using the double reporter PRV, we also found that 25-hydroxycholesterol had a significant inhibitory effect on PRV both in vivo and in vitro. These results suggested that the double reporter PRV based on PRV variant HN1201 should be an excellent tool for basic virology studies and evaluating antiviral agents.
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Affiliation(s)
- Peng-Fei Fu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Xuan Cheng
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Bing-Qian Su
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Li-Fang Duan
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Cong-Rong Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Xin-Rui Niu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Jiang Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
| | - Guo-Yu Yang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
| | - Bei-Bei Chu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
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Qi H, Wu H, Abid M, Qiu HJ, Sun Y. Establishment of a Fosmid Library for Pseudorabies Virus SC Strain and Application in Viral Neuronal Tracing. Front Microbiol 2020; 11:1168. [PMID: 32595620 PMCID: PMC7300229 DOI: 10.3389/fmicb.2020.01168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 05/07/2020] [Indexed: 01/30/2023] Open
Abstract
Pseudorabies virus (PRV) is a member of Alphaherpesvirinae subfamily, its neurotropism and latency infection attract the attention of many scientists. PRV tagged with a fluorescent reporter gene as a tracker has been used to analyze neuronal circuits, including anterograde and retrograde. In this study, we used fosmid library to construct a rapid and efficient platform to generate recombinant PRV. Firstly, the highly purified PRV ShuangCheng (SC) genomic DNA was sheared randomly into approximately 30–49-kb DNA fragments. After end-blunting and phosphorylation, the DNA fragments were cloned into the fosmid vector and transformed into Escherichia coli. A total of 200 fosmids that cover the complete genome of PRV SC was sequenced. Thirteen fosmid combinations in five groups were transfected into Vero cells, respectively, and each group can successfully rescue PRV strain SC. There was no significant difference between wild type and recombinant in both morphology and growth kinetics. In the next step, an enhanced green fluorescent protein (EGFP) was fused into the amino-terminal of UL36 protein by Red/ET recombination technology, and recombinant rPRV SC-UL36-EGFP was rescued successfully. At last, the single viral particles with green fluorescent were monitored retrograde moving in the axon with an average velocity of 0.71 ± 0.43 μm/s at 0.5–2 h post infection (hpi) and anterograde moving with an average velocity of 0.75 ± 0.49 μm/s at eight hpi. Integration of fosmid library and Red/ET recombination technology in our work was highly efficient and stable for constructing PRV recombinants. This study will accelerate understanding the biology of PRV and the development of novel vaccines.
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Affiliation(s)
- Hansong Qi
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Hongxia Wu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Muhammad Abid
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Hua-Ji Qiu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yuan Sun
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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Zheng K, Jiang FF, Su L, Wang X, Chen YX, Chen HC, Liu ZF. Highly Efficient Base Editing in Viral Genome Based on Bacterial Artificial Chromosome Using a Cas9-Cytidine Deaminase Fused Protein. Virol Sin 2019; 35:191-199. [PMID: 31792738 PMCID: PMC7198655 DOI: 10.1007/s12250-019-00175-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/09/2019] [Indexed: 02/04/2023] Open
Abstract
Viruses evolve rapidly and continuously threaten animal health and economy, posing a great demand for rapid and efficient genome editing technologies to study virulence mechanism and develop effective vaccine. We present a highly efficient viral genome manipulation method using CRISPR-guided cytidine deaminase. We cloned pseudorabies virus genome into bacterial artificial chromosome, and used CRISPR-guided cytidine deaminase to directly convert cytidine (C) to uridine (U) to induce premature stop mutagenesis in viral genes. The editing efficiencies were 100%. Comprehensive bioinformatic analysis revealed that a large number of editable sites exist in pseudorabies virus (PRV) genomes. Notably, in our study viral genome exists as a plasmid in E. coli, suggesting that this method is virus species-independent. This application of base-editing provided an alternative approach to generate mutant virus and might accelerate study on virulence and vaccine development.
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Affiliation(s)
- Ke Zheng
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
- Gene Editing Research Center, Hebei University of Science and Technology, Shijiazhuang, 050018, China
| | - Fang-Fang Jiang
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Le Su
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xin Wang
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu-Xin Chen
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huan-Chun Chen
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zheng-Fei Liu
- State Key Laboratory of Agricultural Microbiology and Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China.
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Tong W, Zheng H, Li GX, Gao F, Shan TL, Zhou YJ, Yu H, Jiang YF, Yu LX, Li LW, Kong N, Tong GZ, Li JC. Recombinant pseudorabies virus expressing E2 of classical swine fever virus (CSFV) protects against both virulent pseudorabies virus and CSFV. Antiviral Res 2019; 173:104652. [PMID: 31751590 DOI: 10.1016/j.antiviral.2019.104652] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/14/2019] [Accepted: 11/16/2019] [Indexed: 10/25/2022]
Abstract
Both classical swine fever (CSF) and pseudorabies are highly contagious, economically significant diseases of swine in China. Although vaccination with the C-strain against classical swine fever virus (CSFV) is widely carried out and severe outbreaks of CSF seldom occur in China, CSF is sporadic in many pig herds and novel sub-subgenotypes of CSFV endlessly emerge. Thus, new measures are needed to eradicate CSFV from Chinese farms. The emergence of a pseudorabies virus (PRV) variant also posed a new challenge for the control of swine pseudorabies. Here, the recombinant PRV strain JS-2012-ΔgE/gI-E2 expressing E2 protein of CSFV was developed by inserting the E2 expression cassette into the intergenic region between the gG and gD genes of the gE/gI-deletion PRV variant strain JS-2012-ΔgE/gI. The recombinant virus was stable when passaged in vitro. A single vaccination of JS-2012-ΔgE/gI-E2 via intramuscular injection fully protected against lethal challenges of PRV and CSFV. Vaccination of piglets with the recombinant JS-2012-ΔgE/gI-E2 in the presence of high levels of maternally derived antibodies (Abs) to PRV can provide partial protection against lethal challenge of CSFV. Vaccination of the recombinant PRV JS-2012-ΔgE/gI-E2 strain did not induce the production of Abs to the gE protein of PRV or to the CSFV proteins other than E2. Thus, JS-2012-ΔgE/gI-E2 appears to be a promising recombinant marker vaccine candidate against PRV and CSFV for the control and eradication of the PRV variant and CSFV.
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Affiliation(s)
- Wu Tong
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China; Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China
| | - Hao Zheng
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Guo-Xin Li
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Fei Gao
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Tong-Ling Shan
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Yan-Jun Zhou
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Hai Yu
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Yi-Feng Jiang
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Ling-Xue Yu
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Li-Wei Li
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Ning Kong
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China
| | - Guang-Zhi Tong
- Shanghai Veterinary Research Institute, CAAS, Shanghai, 200241, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China.
| | - Ji-Chang Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China.
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Hübner A, Keil GM, Kabuuka T, Mettenleiter TC, Fuchs W. Efficient transgene insertion in a pseudorabies virus vector by CRISPR/Cas9 and marker rescue-enforced recombination. J Virol Methods 2018; 262:38-47. [PMID: 30248362 DOI: 10.1016/j.jviromet.2018.09.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/19/2018] [Accepted: 09/19/2018] [Indexed: 02/07/2023]
Abstract
For development of vectored vaccines against porcine pathogens the genome of the pseudorabies virus vaccine strain Bartha (PrV-Ba) was previously cloned as an infectious bacterial artificial chromosome (BAC), containing the bacterial replicon and a reporter gene cassette encoding enhanced green fluorescent protein (EGFP) at the nonessential glycoprotein G locus. To facilitate substitution of this insertion, this BAC was now modified by deletion of the adjacent promoter and initiation codon of the essential glycoprotein D (gD) gene of PrV-Ba. Furthermore, rabbit kidney (RK13) cells stably expressing Cas9 nuclease and an EGFP gene-specific guide RNA were prepared to induce site specific cleavage of the BAC DNA. After co-transfection of these cells with the modified BAC and recombination plasmids containing expression cassettes for new transgenes flanked by PrV DNA sequences including the intact 5'-end of the gD gene, >95% of the recombinants exhibited the desired gene substitutions, while no EGFP-expressing progeny virus was detectable. This approach was used for insertion and expression of the open reading frames E199L, CP204L (p30) and KP177R (p22) of African swine fever virus. The studies revealed that codon adaptation significantly enhanced expression of E199L, and that the chimeric CAG promoter increased transgene expression compared to cytomegalovirus immediate-early promoters.
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Affiliation(s)
- Alexandra Hübner
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493, Greifswald-Insel Riems, Germany
| | - Günther M Keil
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493, Greifswald-Insel Riems, Germany
| | - Tonny Kabuuka
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493, Greifswald-Insel Riems, Germany
| | - Thomas C Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493, Greifswald-Insel Riems, Germany
| | - Walter Fuchs
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, 17493, Greifswald-Insel Riems, Germany.
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