Figure 1.

The expression of angiotensin‐converting enzyme 2 (ACE2) is upregulated by coronaviruses. A, ACE2 expression is upregulated in the lungs of severe acute respiratory syndrome coronavirus (SARS‐CoV) MA15‐infected C57Bl/6 mice. At 24 hours after the intranasal instillation of 10² or 10³ PFU of SARS‐CoV MA15 in 50 µL of phosphate buffered saline (PBS) or mock infection with PBS alone, lungs were harvested, and total RNA was isolated and subjected to microarray analysis. ACE2 expression data were retrieved from the Gene Expression Omnibus (GEO) microarray database (National Center for Biotechnology Information [NCBI] accession: PRJNA149057; GEO: GSE33266). B, ACE2 expression is upregulated in primary human airway epithelial cells in response to wild‐type Middle East respiratory syndrome coronavirus (MERS‐CoV; icMERS‐CoV EMC2012). Human airway epithelial cells were infected with a multiplicity of infection of 5 PFU per cell. Infected samples were collected at the time points as indicated above. ACE2 expression data were retrieved from the GEO microarray database (NCBI accession: PRJNA391962; GEO: GSE100504)