DTX3L is a histone E3 ligase, which is involved in DNA damage repair.39 Zahng et al. has also shown that DTX3L-PARP9 complex promotes ISG expression and thus controls viral infection.40 However, it has not been reported that cGAMP can modulate ISG expression through DTX3L-PARP9. Here, PARP9 is linked to viral infectious disease.