Fig. 5.

Transgenic DF1 cells expressing different animal species ACE2 and TMPRSS2 genes. (A) DF1 cells were transfected with PiggyBac® plasmid containing the ACE2 and TMPRSS2 genes from house cat (Felis catus), horse (Equus ferus), domestic pig (Sus domesticus), goat (Capra aegagrus), Golden hamster (Mesocricetus auratus), Little Brown bat (Myotis lucifugus) and Great Roundleaf bat (Hipposideros armiger). Cells were first created with the animal ACE2 gene and FACS purified based on GFP expression. The animal TMPRSS2 gene was then transfected into the DF1 cells expressing the animal ACE2 gene. Two-color FACS was performed based on GFP and RFP expression. Transgenic cells expressing animal ACE2 and TMPRSS2 were grown at 37C in 5% CO₂. After 72 h, RNA was extracted and primers specific for the animals ACE2 and animal TMPRSS2 were used with RT-PCR to confirm animal species ACE2 and TMPRSS2 expression in DF1 cells.