PARP9 and viral infectious disease: PARP9 and DTX3L form a tight complex (Takeyama et al, 2003) that has suggested roles in DNA repair, as well as in the response to bacterial or viral infection (Huang et al, 2023; Thirunavukkarasu et al, 2023; Yan et al, 2023; Zhang et al, 2015) and carcinogenesis (Bachmann et al, 2014).