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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of the COVID-19 pandemic. While the development of vaccines and the emergence of antiviral therapeutics is promising, alternative strategies to combat COVID-19 (and potential future pandemics) remain an unmet need. Coronaviruses feature a unique mechanism that may present opportunities for therapeutic intervention: the RNA polymerase complex of coronaviruses is distinct in its ability to proofread and remove mismatched nucleotides during genome replication and transcription. The proofreading activity has been linked to the exonuclease (ExoN) activity of non-structural protein 14 (NSP14). Here, we review the role of NSP14, and other NSPs, in SARS-CoV-2 replication and describe the assays that have been developed to assess the ExoN function. We also review the nucleoside analogs and non-nucleoside inhibitors known to interfere with the proofreading activity of NSP14. Although not yet validated, the potential use of non-nucleoside proofreading inhibitors in combination with chain-terminating nucleosides may be a promising avenue for the development of anti-CoV agents.
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http://dx.doi.org/10.3390/molecules27092918 | DOI Listing |
J Physiol
September 2025
Department of Physiology, Anatomy & Genetics, University of Oxford and Daegu-Gyeongbuk Institute of Science and Technology, South Korea.
The cardiac pacemaker activity is formed from multiple interlocking physiological networks, any one of which can generate rhythm. The interlocking is reciprocal so that they automatically replace each other. In such interlocking control systems, the association scores for individual components are necessarily low, even though causation, measured by the electric current carried by the relevant ion channels, is large.
View Article and Find Full Text PDFLancet Microbe
August 2025
Department of Microbiology and Immunology, Canadian Center for Vaccinology (CCfV), Faculty of Medicine, Dalhousie University, Halifax, NS B3H 4H7, Canada; Laboratory of Immunity, Shantou University Medical College, Guangdong, China; BioForge Canada Limited, Halifax, NS, Canada. Electronic address: d
Genome Med
August 2025
Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford, OX3 7DQ, UK.
Background: Single base substitution (SBS) mutations, particularly C > T and T > C, are increased owing to unrepaired DNA replication errors in mismatch repair-deficient (MMRd) cancers. Excess CpG > TpG mutations have been reported in MMRd cancers defective in mismatch detection (dMutSα), but not in mismatch correction (dMutLα). Somatic CpG > TpG mutations conventionally result from unrepaired spontaneous deamination of 5'-methylcytosine throughout the cell cycle, causing T:G mismatches and signature SBS1.
View Article and Find Full Text PDFDNA Repair (Amst)
August 2025
Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan. Electronic address:
Chain-terminating nucleoside analogs (CTNAs) are incorporated into genome during replication by replicative polymerase delta (Polδ) and epsilon (Polε), then inhibit DNA synthesis by preventing subsequent polymerization. The proofreading exonuclease activity of Polε removes the incorporated CTNAs, thereby contributing to cellular tolerance to these drugs. However, the contribution of Polδ's proofreading exonuclease activity has not been clarified, nor has the relationship between Polδ and Polε been well understood.
View Article and Find Full Text PDFNat Commun
August 2025
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA.
Coronaviruses rely on a multifunctional replication-transcription complex to ensure genome fidelity and support viral propagation. Within this complex, the nsp14-nsp10 heterodimer possesses 3'-5' exoribonuclease (ExoN) activity, while nsp14 alone functions as an N7-methyltransferase and the nsp16/nsp10 complex completes viral RNA capping via its 2'-O-methyltransferase. Here, we report that nsp14 and nsp10 ligate [FeS] clusters when purified anoxically, in sites previously modeled as zinc centers.
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