Identification of the molecular determinants for nuclear import of PRV EP0

Pseudorabies virus (PRV) early protein EP0 is a homologue of the herpes simplex virus 1 (HSV-1) immediate- early protein ICP0, which is a multifunctional protein and important for HSV-1 infection. However, the definite function of EP0 during PRV infection is not clear. In this study, to determine if EP0 might localize to the nucleus, as it is shown for its homologue in HSV-1, the subcellular localization pattern and molecular determinants for the nuclear import of EP0 were investigated. EP0 was demonstrated to predominantly target the nucleus in both PRV infected- and plasmid-transfected cells. Furthermore, the nuclear import of EP0 was shown to be dependent on the Ran-, importin alpha 1-, alpha 3-, alpha 7-, beta 1- and transportin-1-mediated multiple pathways. Taken together, these data will open up new horizons for portraying the biological roles of EP0 in the course of PRV lytic cycle.