Two lines express the hACE2 gene under the control of the mouse ACE2 promotor6,7; one was made using the CRISPR/Cas9 technology.7 The third strain uses the lung ciliated epithelial cell hepatocyte nuclear factor-3/forkhead homologue 4 (HFH4) promoter.8,9 An additional approach was to transfect wild-type mice with an adenovirus carrying the hACE2 gene.10 Overall, with the exception of the HFH4 mice, in which there was some lethality, infection of these three mouse strains with SARS-CoV-2 results in mild clinical symptoms and no lethality. Here, FOXJ1 is linked to infection.