Viral infection involves complex set of events orchestrated by multiple viral proteins. To identify functions of SARS-CoV-2 proteins, we performed transcriptomic analyses of cells expressing individual viral proteins. Expression of Nsp14, a protein involved in viral RNA replication, provoked a dramatic remodeling of the transcriptome that strongly resembled that observed following SARS-CoV-2 infection. Moreover, Nsp14 expression altered the splicing of more than 1000 genes and resulted in a dramatic increase in the number of circRNAs, which are linked to innate immunity. These effects were independent of the Nsp14 exonuclease activity and required the N7-guanine-methyltransferase domain of the protein. Activation of the NFkB pathway and increased expression of occurred early upon Nsp14 expression. We identified IMPDH2, which catalyzes the rate-limiting step of guanine nucleotides biosynthesis, as a key mediator of these effects. Nsp14 expression caused an increase in GTP cellular levels, and the effect of Nsp14 was strongly decreased in the presence of IMPDH2 inhibitors. Together, our data demonstrate an unknown role for Nsp14 with implications for therapy.
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http://dx.doi.org/10.7554/eLife.71945 | DOI Listing |
Biochemistry
January 2025
National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, Maryland 20850, United States.
SARS-CoV-2 infections led to a worldwide pandemic in 2020. As of 2024, therapeutics against SARS-CoV-2 have continued to be desirable. NSP14 is a dual-function methyltransferase (MTase) and exonuclease (ExoN) with key roles in SARS-CoV-2 genome propagation and host immune system evasion.
View Article and Find Full Text PDFEmerg Microbes Infect
January 2025
State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
N6-methyladenosine (m6A) is the most prevalent post-transcriptional modification in eukaryotic RNA and is also present in various viral RNAs, where it plays a crucial role in regulating the viral life cycle. However, the molecular mechanisms through which viruses regulate host RNA m6A methylation are not fully understood. In this study, we reveal that SARS-CoV-2 and HCoV-OC43 infection enhance host m6A modification by activating the mTORC1 signaling pathway.
View Article and Find Full Text PDFmSphere
December 2024
Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.
Unlabelled: We previously reported that mutations outside the spike protein play a role in the attenuation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.1 variant in human ACE2 transgenic mice (K18-hACE2). Here, we assessed the pathogenicity of SARS-CoV-2 (WA1/2020) containing mutations from the Omicron BA.
View Article and Find Full Text PDFCell Commun Signal
November 2024
Department of Microbiology and Immunology, Tulane University, New Orleans, LA, 70112, USA.
Mol Immunol
November 2024
Hubei Key Laboratory of Cognitive and Affective Disorders, Wuhan Institute of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China; Department of Immunology, School of Medicine, Jianghan University, Wuhan, China. Electronic address:
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