Stimulates viral immediate-early (IE) transcription. Plays a role in the inhibition of the host innate repsonse by targeting STING1 and thus the cGAS-STING pathway (PubMed:28132838, PubMed:32581105). Counteracts also host DAXX-mediated repression of viral transcription. Displaces a DAXX-binding protein, ATRX, from nuclear domain 10 sites (ND10) shortly after infection (PubMed:18922870). Increases the basal level of SUMOylated DAXX in infected cells (PubMed:19369322). Stimulates quiescent cells to re-enter the cell cycle, proceed through G1 and enter the S phase (PubMed:12610120). Interacts with hypophosphorylated forms of RB1 and induces their degradation by the proteasome without involving ubiquitin conjugation (PubMed:12626766). Interacts with the host protein DAXX; this interaction takes place at ND10 and induces the reversal of DAXX-mediated repression of viral transcription (PubMed:18922870, PubMed:19369322). Interacts with UL35 (PubMed:15308743). Interacts with host TMEM173/STING1; this interaction inhibits the cGAS/STING pathway (PubMed:28132838, PubMed:32581105). Interacts with host RB1; this interaction mediates RB1 proteasomal degradation (PubMed:12626766). Present in the nucleus shortly after infection as well as during the late phase of viral morphogenesis. Detected at nuclear domain 10 (ND10). S-nitrosylation limits ability to undermine the cGAS/STING antiviral pathway. Belongs to the herpesviridae pp71 family.