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Ye C, Chen J, Cheng X, Zhou S, Jiang S, Xu J, Zheng H, Tong W, Li G, Tong G. Functional analysis of the UL24 protein of suid herpesvirus 1. Virus Genes 2019; 55:76-86. [PMID: 30478778 DOI: 10.1007/s11262-018-1619-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 11/23/2018] [Indexed: 11/28/2022]
Abstract
The UL24 homologous genes are conserved in alphaherpesviruses. However, the proximity of the UL24 gene and the UL23 gene encoding for thymidine kinase (TK) in the genome of suid herpesvirus 1 (SuHV-1) makes it difficult to mutate UL24 without affecting the expression of the TK gene, and thus functional studies of the UL24 gene have lagged behind. In this study, CRISPR/Cas9 and homologous recombination were adopted to generate UL24 and TK mutant viruses. Deletion of either the UL24 or the TK gene resulted in significantly reduced SuHV-1 replication and spread capacity in Vero cells. However, UL24-deleted virus still maintained a certain degree of lethality in mice, while TK-deleted viruses completely lost their lethality in mice. Similarly, neurovirulence of UL24-deleted virus in mice was not significantly affected compared to parental virus. In comparison, infection with the TK-deleted viruses resulted in significantly reduced neurovirulence and complete loss of lethality. In addition, and for the first time, viral UL24 protein was found to be expressed late during SuHV-1 infection; enhanced green fluorescence protein (eGFP) labeled UL24 protein was shown to be localized in the nucleus via heterologous expression. In conclusion, the UL24 gene of SuHV-1 encodes a nuclear-localized viral protein and acts as a minor virulence-associated factor compared to the TK gene.
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Affiliation(s)
- Chao Ye
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Jing Chen
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Xuefei Cheng
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Shasha Zhou
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Shan Jiang
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Jingjing Xu
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
| | - Hao Zheng
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Wu Tong
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Guoxin Li
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Guangzhi Tong
- Department of Swine Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Minhang District, Shanghai, 200241, China.
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
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