Early protein that promotes the accumulation and nuclear export of viral intronless RNA transcripts by interacting with mRNAs and cellular export proteins. Probably acts as a viral splicing factor that regulates viral RNA splicing. Functions as a multifunctional regulator of the expression of viral lytic genes. Homodimer. Homodimerization is required for transactivation (By similarity). Interacts with host ALYREF (PubMed:15155762). Associates in a complex with RNA, and host export factors NXF1/TAP and ALYREF; these interactions allow nuclear export of viral transcripts (Probable). Interacts with protein K-bZIP/K8; this interaction promotes viral gene expression during lytic infection. Shuttles between the nucleus and the cytoplasm. Transactivated by ORF50 protein. Binds viral intronless RNAs. ORF50 and ORF57 are the earliest genes expressed in the lytic cycle. Belongs to the HHV-1 ICP27 protein family.