Mutational screening reveals a cluster of residues within the SARS-CoV-2 nsp1 N-terminus that confers RNA-targeting selectivity
- 1University of California, Berkeley
Abstract
The SARS-CoV-2 nsp1 protein is a virulence factor that broadly inhibits cellular gene expression. Although cellular mRNAs are translationally inhibited by nsp1 and subsequently degraded, viral transcripts possess a 5' leader sequence (CoV2L) that enables them to escape nsp1-mediated repression. Both transcript targeting selectivity and mRNA decay require coordination by the nsp1 N-terminal domain (NTD) through an unknown mechanism. Here, we generated an alanine-scanning library of mutations encompassing all residues in the nsp1 NTD to gain a deeper understanding of how this domain coordinates nsp1 function. We screened this library for the ability to repress mRNA bearing a host- or CoV2L-derived 5' untranslated region, revealing two predominant clusters of residues required for target selectivity. These largely comprised adjacent surface-exposed beta-sheets on the NTD, whose deletion rendered CoV2L-containing mRNA susceptible to repression and prevented nsp1-induced mRNA decay. This work provides residue-level information on the role of the NTD in distinguishing among mRNA targets and further links nsp1 target selectivity to mRNA decay.
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BibTeX
@misc{guillen2026mutational,
title = {{Mutational screening reveals a cluster of residues within the SARS-CoV-2 nsp1 N-terminus that confers RNA-targeting selectivity}},
author = {J. V. Guillen and S. A. Tokamov and B. A. Glaunsinger},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.22.753304},
url = {https://www.biorxiv.org/content/10.64898/2026.09.22.753304v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Mutational screening reveals a cluster of residues within the SARS-CoV-2 nsp1 N-terminus that confers RNA-targeting selectivity
AU - J. V. Guillen
AU - S. A. Tokamov
AU - B. A. Glaunsinger
PY - 2026
DA - 2026/09/22
PB - bioRxiv
DO - 10.64898/2026.09.22.753304
UR - https://www.biorxiv.org/content/10.64898/2026.09.22.753304v1
AB - The SARS-CoV-2 nsp1 protein is a virulence factor that broadly inhibits cellular gene expression. Although cellular mRNAs are translationally inhibited by nsp1 and subsequently degraded, viral transcripts possess a 5' leader sequence (CoV2L) that enables them to escape nsp1-mediated repression. Both transcript targeting selectivity and mRNA decay require coordination by the nsp1 N-terminal domain (NTD) through an unknown mechanism. Here, we generated an alanine-scanning library of mutations encompassing all residues in the nsp1 NTD to gain a deeper understanding of how this domain coordinates nsp1 function. We screened this library for the ability to repress mRNA bearing a host- or CoV2L-derived 5' untranslated region, revealing two predominant clusters of residues required for target selectivity. These largely comprised adjacent surface-exposed beta-sheets on the NTD, whose deletion rendered CoV2L-containing mRNA susceptible to repression and prevented nsp1-induced mRNA decay. This work provides residue-level information on the role of the NTD in distinguishing among mRNA targets and further links nsp1 target selectivity to mRNA decay.
ER -