Cell Paper: Genome-wide CRISPR Screen Reveal Host Factors Critical for SARS-CoV-2 Infection

COVID-19 (SARS-CoV-2) is a major public heatlh threat with more than 1,200,000 deaths worldwide. The first stage in the coronavirus life cycle is viral entry where the viral spike protein will bind to a specific cell surface receptor. The spike proteins of SARS-CoV-2, as well as SARS-CoV-1 and NL63 use angiotensin-converting enzyme 2 (ACE2) as a receptor for binding. An antibody for this ACE2 protein has been produced by ProSci Inc. (Catalog No. 3217) that has been shown to function in immunohistochemistry and immunofluorescence experiments in human samples, and western blot experiments in human, mouse, and rat samples.

Anti-ACE2 antibodies (3217) from ProSci Inc. were used in the recent study with KO and regulation validation (Wei et al, Cell, 2020). A genome wide CRISPR screen of vervet monkey 

ACE2 (3217) Cell article graph | ProSci Inc.

and human cells with SARS-CoV-2, MERS-CoV, a coronavirus expressing SARS-CoV-1 spike protein, and vesicular stomatitis virus expressing the SARS-CoV-2 spike protein, was conducted by a lab at Yale University to find host factors critical for SARS-CoV-2 infection (Wei et al, Cell, 2020).

In this study, 14 genes including ACE2 and SMARCA4, were found in the SARS-lineage viruses but not in MERS-CoV suggesting that these genes were used by SARS viruses in host entry. ACE2, HMGB1, SMARCA4, along with other genes, were found to have pro-viral function in both cell lines suggesting that the function of these genes is conserved across species. The SMARCA4 subunit of the SWI/SNF remodeling complex was the second strongest hit in SARS_CoV-2 viruses with ACE2 being the strongest hit. The SWI/SNF complex is a remodeling complex that regulates chromatin accessibility and gene expression. Knockout experiments of ACE2 and SMARCA4 both showed decrease in protein abundance that was correlated with an increased level of protection against SARS-CoV-2. Small moecule antagonists of teh SMARCA4 protein were shown to confrere protection of virus induced cell death while also decreasing the frquency of viral infection. In this genetic screen, the HMGB1 gene was found to be necessary for ACE2 expression. HMGB1 knockout cells were found to have a significant reduction in ACE2 protein via western blot analysis, and a decreased susceptibility to SARS-CoV-2 infection.

ACE2 Antibody Cat No. 3217 - Regulated Expression, KO Validation | ProSci Inc.

ProSci Incorporated has a full list of the antibodies against these genes (pro-viral and anti-viral to SARS-CoV-2).