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Yao M, Cheng Z, Li X, Li Y, Ye W, Zhang H, Liu H, Zhang L, Lei Y, Zhang F, Lv X. N6-methyladenosine modification positively regulate Japanese encephalitis virus replication. Virol J 2024; 21:23. [PMID: 38243270 PMCID: PMC10799421 DOI: 10.1186/s12985-023-02275-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 12/20/2023] [Indexed: 01/21/2024] Open
Abstract
N6-methyladenosine (m6A) is present in diverse viral RNA and plays important regulatory roles in virus replication and host antiviral innate immunity. However, the role of m6A in regulating JEV replication has not been investigated. Here, we show that the JEV genome contains m6A modification upon infection of mouse neuroblast cells (neuro2a). JEV infection results in a decrease in the expression of m6A writer METTL3 in mouse brain tissue. METTL3 knockdown by siRNA leads to a substantial decrease in JEV replication and the production of progeny viruses at 48 hpi. Mechanically, JEV triggered a considerable increase in the innate immune response of METTL3 knockdown neuro2a cells compared to the control cells. Our study has revealed the distinctive m6A signatures of both the virus and host in neuro2a cells infected with JEV, illustrating the positive role of m6A modification in JEV infection. Our study further enhances understanding of the role of m6A modification in Flaviviridae viruses.
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Affiliation(s)
- Min Yao
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - Zhirong Cheng
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
- College of Life Science, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Xueyun Li
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
- College of Basic Medicine, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Yuexiang Li
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - Wei Ye
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - Hui Zhang
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - He Liu
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - Liang Zhang
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - Yingfeng Lei
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China
| | - Fanglin Zhang
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China.
| | - Xin Lv
- Department of Microbiology, Airforce Medical University, Xi'an, 710032, Shaanxi, China.
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Sistrom M, Andrews H, Edwards DL. Comparative genomics of Japanese encephalitis virus shows low rates of recombination and a small subset of codon positions under episodic diversifying selection. PLoS Negl Trop Dis 2024; 18:e0011459. [PMID: 38295106 PMCID: PMC10861042 DOI: 10.1371/journal.pntd.0011459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 02/12/2024] [Accepted: 01/11/2024] [Indexed: 02/02/2024] Open
Abstract
Orthoflavivirus japonicum (JEV) is the dominant cause of viral encephalitis in the Asian region with 100,000 cases and 25,000 deaths reported annually. The genome is comprised of a single polyprotein that encodes three structural and seven non-structural proteins. We collated a dataset of 349 complete genomes from a number of public databases, and analysed the data for recombination, evolutionary selection and phylogenetic structure. There are low rates of recombination in JEV, subsequently recombination is not a major evolutionary force shaping JEV. We found a strong overall signal of purifying selection in the genome, which is the main force affecting the evolutionary dynamics in JEV. There are also a small number of genomic sites under episodic diversifying selection, especially in the envelope protein and non-structural proteins 3 and 5. Overall, these results support previous analyses of JEV evolutionary genomics and provide additional insight into the evolutionary processes shaping the distribution and adaptation of this important pathogenic arbovirus.
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Affiliation(s)
- Mark Sistrom
- Department of Industry, Trade and Tourism, Berrimah Veterinary Laboratories, Darwin, Australia
- Research Institute for the Environment and Livelihoods, Faculty of Science and Technology, Charles Darwin University, Casuarina, Australia
| | - Hannah Andrews
- Department of Industry, Trade and Tourism, Berrimah Veterinary Laboratories, Darwin, Australia
| | - Danielle L. Edwards
- Research Institute for the Environment and Livelihoods, Faculty of Science and Technology, Charles Darwin University, Casuarina, Australia
- Department of Natural Sciences, Museum and Art Gallery of the Northern Territory, Darwin, Australia
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Lin X, Sha Z, Trimpert J, Kunec D, Jiang C, Xiong Y, Xu B, Zhu Z, Xue W, Wu H. The NSP4 T492I mutation increases SARS-CoV-2 infectivity by altering non-structural protein cleavage. Cell Host Microbe 2023; 31:1170-1184.e7. [PMID: 37402373 DOI: 10.1016/j.chom.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 04/13/2023] [Accepted: 06/09/2023] [Indexed: 07/06/2023]
Abstract
The historically dominant SARS-CoV-2 Delta variant and the currently dominant Omicron variants carry a T492I substitution within the non-structural protein 4 (NSP4). Based on in silico analyses, we hypothesized that the T492I mutation increases viral transmissibility and adaptability, which we confirmed with competition experiments in hamster and human airway tissue culture models. Furthermore, we showed that the T492I mutation increases the replication capacity and infectiveness of the virus and improves its ability to evade host immune responses. Mechanistically, the T492I mutation increases the cleavage efficiency of the viral main protease NSP5 by enhancing enzyme-substrate binding, which increases production of nearly all non-structural proteins processed by NSP5. Importantly, the T492I mutation suppresses viral-RNA-associated chemokine production in monocytic macrophages, which may contribute to the attenuated pathogenicity of Omicron variants. Our results highlight the importance of NSP4 adaptation in the evolutionary dynamics of SARS-CoV-2.
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Affiliation(s)
- Xiaoyuan Lin
- School of Life Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China; Institut für Virologie, Freie Universität Berlin, Robert-von-Ostertag-Straße 7, 14163 Berlin, Germany
| | - Zhou Sha
- School of Life Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China
| | - Jakob Trimpert
- Institut für Virologie, Freie Universität Berlin, Robert-von-Ostertag-Straße 7, 14163 Berlin, Germany
| | - Dusan Kunec
- Institut für Virologie, Freie Universität Berlin, Robert-von-Ostertag-Straße 7, 14163 Berlin, Germany
| | - Chen Jiang
- School of Life Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China
| | - Yan Xiong
- School of Life Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China
| | - Binbin Xu
- School of Pharmaceutical Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China
| | - Zhenglin Zhu
- School of Life Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China.
| | - Weiwei Xue
- School of Pharmaceutical Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China.
| | - Haibo Wu
- School of Life Sciences, Chongqing University, No.55 Daxuecheng South Road, Shapingba, Chongqing 401331, China.
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