RING-finger E3 ubiquitin ligase that plays an important regulatory role during the initial stages of infection. Migrates to specific nuclear foci early in infection supposely to prepare the sites for viral transcription and replication by targeting and ubiquitinating host proteins. Acts as a transcriptional activator and activates a number of viral promoters including itself, IE1 and the promoter of 39K gene. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Homooligomer. Auto-ubiquitinated. Belongs to the alphabaculovirus IE2 protein family.