CGAS and viral infectious disease: HeLa was chosen as the founder to create TRIM56 KO cells because this well-characterized cell line (1) has been widely used as a cell culture model to study innate immunity against viral infections, (2) possesses intact dsRNA- and dsDNA-sensing antiviral pathways including those dependent on TLR3 [5] and on cGAS-STING [17,18], and (3) expresses readily detectable, endogenous TRIM56 mRNA and protein [3,5].