Although mouse (M. musculus) ACE2 was considered unable to bind SARS-CoV-2 spike (35) and unable to support SARS-CoV-2 replication and disease development (69), it was reported that M. musculus transgenic for the human ACE2 gene are susceptible to infection by SARS-CoV-2 and develop mild disease COVID-19-like signs after viral exposure (38, 69). Here, ACE2 is linked to COVID-19.