Promotes the nuclear export of a subset of early and late viral mRNAs by interacting with intronless mRNAs and cellular export proteins. Additionally may prevent the establishment of cellular antiviral state, by acting as an alternative splicing factor for cellular RNAs such as STAT1, resulting in a STAT1 mRNA incapable of producing the STAT1alpha isoform (By similarity). Interacts with host XPO1 and with the XPO1 export pathway components small GTPase RAN and nucleoporin NUP214. Interacts with host SPEN, OTT1 and OTT3 (By similarity). shuttles between the nucleus and the cytoplasm. Binds viral intronless RNAs. Phosphorylated by cellular protein kinase CK2. Belongs to the HHV-1 ICP27 protein family.