Atlas of ACE2 gene expression in mammals reveals novel insights in transmission of SARS-Cov-2

Kun Sun; Liuqi Gu; Li Ma; Yunfeng Duan

The culprit of this pandemic is a new coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 1 , which belongs to the same beta coronavirus family as SARS-CoV and MERS-CoV, the other two viruses that caused outbreaks in the past two decades 2 . Among myriad biological questions to be answered regarding SARS-CoV-2, one that is crucial and has intrigued much interest is the host origin and its mode of transmission to humans. SARS-CoV-2 and SARS-CoV are closely related, and both invade human cells via attaching their S proteins to a host transmembrane protein called angiotensin converting enzyme 2 (ACE2) as the entry point 3 . Using transcriptome data, some studies analyzed spatial expression patterns of ACE2 in various tissues and cell types of the human body, and reported that the receptor gene is indeed expressed in the lungs [4] [5] [6] . The connections between ACE2 expression and viral infection are further supported by cases from the United States, which confirmed for the first time the presence of SARS-CoV-2 in both the upper respiratory tract and stool Some studies have suggested that the original host of SARS-CoV-2 may be bats 2 .