Fig. 5. The inserted furin-like cleavage site or furin overexpression does not promote SARS-CoV-2 replication in BHK21 (non-permissive) and Huh7 (permissive) cells.

a Human ACE2 and furin overexpression in BHK21 cells was confirmed with western blot. b–c BHK21 cells with or without human ACE2 or furin overexpression were infected with SARS-CoV-2 or SARS-CoV. Cell lysates and supernatants were collected at 2 and 24hpi for qRT-PCR analysis (n = 3). d Amino-acid sequence alignment of residues around the S₁/S₂ cleavage site of SARS-CoV-2 reference strain (GenBank accession number: MN908947), SARS-CoV-2 HKU001a (MT230904), SARS-CoV-2 HKU001a S₁/S₂mut (MT621560), SARS-CoV GZ50 (AY304495), SARSr-CoV WIV1 (KF367457), and bat-CoV RaTG13 (MN996532). e Furin overexpression in Huh7 cells was confirmed with western blot. f–g Huh7 cells with or without furin overexpression were infected with SARS-CoV-2, SARS-CoV-2 S₁/S₂mut, or SARS-CoV. Cell lysates and supernatants were collected at 2 and 24hpi for qRT-PCR analysis (n = 3). Data represented mean and standard deviations from the indicated number of biological repeats. The experiment in a and e was repeated three times independently with similar results. Statistical significance between groups was determined with two way-ANOVA. ns not significant. Source data are provided as a Source Data file.