CGAS and viral infectious disease: We specifically evaluated several key molecules that are involved in type I IFN activation, including 1) cyclic GMP–AMP synthase (cGAS); 2) stimulator of interferon genes (STING); 3) interferon regulatory factor 3 (IRF3); The cGAS-STING-IRF3 pathway plays critical roles in the induction of type I IFN activation in cells encountered viral infection (21, 22).