ACE2 and infection: Confirming these results, analysis of two additional CRISPR screen reports showed enrichment of the 50 most inactivated SARS-CoV-2 infection candidate MRs on infection-essential genes identified in A549-ACE2 cells3, as well as significant enrichment of the infection-essential genes identified in Calu-3 and Caco-2 cells27 among the candidate MR proteins being inactivated in response to SARS-CoV-2 infection (Supplementary Fig. 4g–i).