SARS-CoV-2 nonstructural protein 1 suppresses host transcription by reducing RNA polymerase II levels

Area of Science:

• Virology
• Molecular Biology
• Genomics

Background:

• The COVID-19 pandemic, caused by SARS-CoV-2, has led to significant global mortality.
• SARS-CoV-2 nonstructural protein 1 (NSP1) is known to inhibit host protein synthesis.
• The impact of NSP1 on host gene transcription remains largely uncharacterized.

Purpose of the Study:

• To investigate the effect of SARS-CoV-2 NSP1 on host gene transcription.
• To develop and apply a robust methodology for quantifying transcriptomic changes in response to NSP1 expression.
• To elucidate the molecular mechanisms by which NSP1 affects host gene expression.

Main Methods:

• Establishment of a reporter system for isolating NSP1-overexpressing cells.
• Integration of thio-labeled RNA sequencing (SLAM-seq) for total and nascent RNA analysis.
• Normalization of RNA sequencing data using External RNA Controls Consortium (ERCC) spike-in standards.

Main Results:

• NSP1 expression causes a global reduction in host mRNA levels, including housekeeping genes.
• Virtually no host genes were found to be significantly upregulated upon NSP1 expression.
• Analysis of nascent RNA revealed that NSP1 obstructs transcription by decreasing RNA polymerase II levels.

Conclusions:

• NSP1 significantly downregulates host gene transcription, impacting cellular processes.
• The developed SLAM-seq and ERCC normalization pipeline provides a reliable framework for studying viral factor effects.
• Findings offer insights into coronavirus-host interactions and potential therapeutic targets for COVID-19.