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A genome-wide CRISPR screen identifies host factors that regulate SARS-CoV-2 entry
Yunkai Zhu1, Fei Feng1, Gaowei Hu1
1Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Biosafety Level 3 Laboratory, Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China.
Nature Communications
|February 12, 2021
Summary
The SARS-CoV-2 spike protein
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- The global spread of SARS-CoV-2 presents significant public health challenges.
- The SARS-CoV-2 spike protein features a multi-basic residue insertion at the S1/S2 cleavage site, a characteristic not found in many other coronaviruses.
- The precise role of this S1/S2 cleavage site in viral entry and pathogenesis remains an area of active investigation.
Purpose of the Study:
- To investigate the functional significance of the multi-basic S1/S2 cleavage site in the SARS-CoV-2 spike protein.
- To identify host factors involved in SARS-CoV-2 entry pathways.
- To compare the entry and transmission efficiency of SARS-CoV-2 variants with intact versus disrupted S1/S2 cleavage sites.
Main Methods:
- Comparative analysis of viral entry pathways for SARS-CoV-2 with intact (Sfull) and deleted (Sdel) S1/S2 cleavage sites.
- Genome-wide CRISPR screening to identify host factors regulating viral entry.
- Experimental validation of identified host factors, including their effect on angiotensin-converting enzyme 2 (ACE2) surface expression.
- In vivo transmission studies in a hamster model.
Main Results:
- The intact spike protein (Sfull) mediates viral entry primarily through plasma membrane fusion.
- Disruption of the S1/S2 cleavage site (Sdel) redirects viral entry to an endosomal pathway.
- CRISPR screening identified novel regulators of endosomal entry specific to the Sdel virus.
- Host factors influencing ACE2 surface expression were found to impact Sfull virus entry.
- The Sdel virus exhibited reduced animal-to-animal transmission compared to the Sfull virus in hamsters.
Conclusions:
- The S1/S2 cleavage site of the SARS-CoV-2 spike protein is a critical determinant of viral entry pathways.
- Modulation of the S1/S2 site impacts viral tropism and transmission efficiency.
- Understanding these entry mechanisms provides valuable insights into coronavirus pathogenesis and potential therapeutic strategies.
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