The causative virus of the COVID-19 pandemic, SARS-CoV-2, uses its nonstructural protein 1 (Nsp1) to suppress cellular, but not viral, protein synthesis through yet unknown mechanisms. We show here that among all viral proteins, Nsp1 has the largest impact on host viability in the cells of human lung origin. Differential expression analysis of mRNA-seq data revealed that Nsp1 broadly alters the cellular transcriptome. Our cryo-EM structure of the Nsp1-40S ribosome complex shows that Nsp1 inhibits translation by plugging the mRNA entry channel of the 40S. We also determined the structure of the 48S preinitiation complex formed by Nsp1, 40S, and the cricket paralysis virus internal ribosome entry site (IRES) RNA, which shows that it is nonfunctional because of the incorrect position of the mRNA 3' region. Our results elucidate the mechanism of host translation inhibition by SARS-CoV-2 and advance understanding of the impacts from a major pathogenicity factor of SARS-CoV-2.
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http://dx.doi.org/10.1016/j.molcel.2020.10.034 | DOI Listing |
J Virol
January 2025
Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Coronaviruses (CoVs) encode non-structural proteins (nsp's) 1-16, which assemble to form replication-transcription complexes that function in viral RNA synthesis. All CoVs encode a proofreading 3'-5' exoribonuclease in non-structural protein 14 (nsp14-ExoN) that mediates proofreading and high-fidelity replication and is critical for other roles in replication and pathogenesis. The enzymatic activity of nsp14-ExoN is enhanced in the presence of the cofactor nsp10.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Chemical Sciences, University of Naples "Federico II", Via Cintia, 21, 80126 Napoli, Italy; CEINGE Advanced Biotechnologies s.c.a r.l. "Franco Salvatore", Via Gaetano Salvatore 486, 80131 Napoli, Italy. Electronic address:
SARS-CoV-2 encodes a 3C-like protease (3CL) that is essential for viral replication. This cysteine protease cleaves viral polyproteins to release functional nonstructural proteins, making it a prime target for antiviral drug development. We investigated the inhibitory effects of halicin, a known c-Jun N-terminal kinase inhibitor, on 3CL.
View Article and Find Full Text PDFResistance-associated substitutions (RASs) are mutations within the hepatitis C (HCV) genome that may influence the likelihood of achieving a sustained virological response (SVR) with direct acting antiviral (DAA) treatment. Clinicians conduct RAS testing to adapt treatment regimens with the intent of improving the likelihood of cure. The Canadian Network Undertaking against Hepatitis C (CANUHC) prospective cohort consists of chronic HCV patients enrolled between 2015 and 2023 across 17 Canadian sites.
View Article and Find Full Text PDFIntegr Biol (Camb)
January 2025
Manipal Academy of Higher Education (MAHE), Manipal 576104, Karnataka, India.
The role of GTF2I (General Transcription Factor2I) alteration has already been reported in thymic cancer as a valuable biomarker. However, the association of GTF2I mutation with renal cancer for prognosis of immunotherapy is not yet examined. The biologic and oncologic significance of GTF2I in renal cancer was examined at multiomics level such as mutation, copy number alteration, structural variants.
View Article and Find Full Text PDFPLoS Pathog
January 2025
Department of Animal, Dairy, and Veterinary Sciences, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America.
Japanese encephalitis virus (JEV), a neuroinvasive and neurovirulent orthoflavivirus, can be prevented in humans with the SA14-14-2 vaccine, a live-attenuated version derived from the wild-type SA14 strain. To determine the viral factors responsible for the differences in pathogenicity between SA14 and SA14-14-2, we initially established a reverse genetics system that includes a pair of full-length infectious cDNAs for both strains. Using this cDNA pair, we then systematically exchanged genomic regions between SA14 and SA14-14-2 to generate 20 chimeric viruses and evaluated their replication capability in cell culture and their pathogenic potential in mice.
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