The presence of an unexpected furine cleavage site at the S1/S2 boundary of SARS-CoV-2 S, which is cleaved during biosynthesis-a novel feature setting this virus apart from SARS-CoV and SARSr-CoVs. Abrogation of this cleavage motif moderately affected SARS-CoV-2 S-mediated entry into VeroE6 or BHK cells but may contribute expand the tropism of this virus, as reported for several highly pathogenic avian influenza viruses and pathogenic Newcastle disease virus.