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Katahira J, Ohmae T, Yasugi M, Sasaki R, Itoh Y, Kohda T, Hieda M, Yokota Hirai M, Okamoto T, Miyamoto Y. Nsp14 of SARS-CoV-2 inhibits mRNA processing and nuclear export by targeting the nuclear cap-binding complex. Nucleic Acids Res 2023; 51:7602-7618. [PMID: 37260089 PMCID: PMC10415132 DOI: 10.1093/nar/gkad483] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/12/2023] [Accepted: 05/21/2023] [Indexed: 06/02/2023] Open
Abstract
To facilitate selfish replication, viruses halt host gene expression in various ways. The nuclear export of mRNA is one such process targeted by many viruses. SARS-CoV-2, the etiological agent of severe acute respiratory syndrome, also prevents mRNA nuclear export. In this study, Nsp14, a bifunctional viral replicase subunit, was identified as a novel inhibitor of mRNA nuclear export. Nsp14 induces poly(A)+ RNA nuclear accumulation and the dissolution/coalescence of nuclear speckles. Genome-wide gene expression analysis revealed the global dysregulation of splicing and 3'-end processing defects of replication-dependent histone mRNAs by Nsp14. These abnormalities were also observed in SARS-CoV-2-infected cells. A mutation introduced at the guanine-N7-methyltransferase active site of Nsp14 diminished these inhibitory activities. Targeted capillary electrophoresis-mass spectrometry analysis (CE-MS) unveiled the production of N7-methyl-GTP in Nsp14-expressing cells. Association of the nuclear cap-binding complex (NCBC) with the mRNA cap and subsequent recruitment of U1 snRNP and the stem-loop binding protein (SLBP) were impaired by Nsp14. These data suggest that the defects in mRNA processing and export arise from the compromise of NCBC function by N7-methyl-GTP, thus exemplifying a novel viral strategy to block host gene expression.
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Affiliation(s)
- Jun Katahira
- Laboratory of Cellular Molecular Biology, Graduate School of Veterinary Sciences, Osaka Metropolitan University, 1-58 Rinku-Orai-kita, Izumisano, Osaka 598-8531, Japan
| | - Tatsuya Ohmae
- Laboratory of Cellular Molecular Biology, Graduate School of Veterinary Sciences, Osaka Metropolitan University, 1-58 Rinku-Orai-kita, Izumisano, Osaka 598-8531, Japan
| | - Mayo Yasugi
- Laboratory of Veterinary Public Health, Graduate School of Veterinary Sciences, Osaka Metropolitan University, 1-58 Rinku-Orai-kita, Izumisano, Osaka 598-8531, Japan
| | - Ryosuke Sasaki
- RIKEN Center for Sustainable Resource Science, Mass Spectrometry and Microscopy Unit, 1-7-22 Suehiro. Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Yumi Itoh
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tomoko Kohda
- Laboratory of Veterinary Epidemiology, Graduate School of Veterinary Sciences, Osaka Metropolitan University, 1-58 Rinku-Orai-kita, Izumisano, Osaka 598-8531, Japan
| | - Miki Hieda
- Department of Medical Technology, Ehime Prefectural University of Health Sciences, 543 Tobe-Cho Takaoda, Iyo, Ehime791-2102, Japan
| | - Masami Yokota Hirai
- RIKEN Center for Sustainable Resource Science, Mass Spectrometry and Microscopy Unit, 1-7-22 Suehiro. Tsurumi, Yokohama, Kanagawa 230-0045, Japan
| | - Toru Okamoto
- Institute for Advanced Co-Creation Studies, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Yoichi Miyamoto
- Laboratory of Nuclear Transport Dynamics, National Institutes of Biomedical Innovation, Health, and Nutrition (NIBIOHN), 7-6-8 Saito Asagi, Ibaraki, Osaka 567-0085, Japan
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