PSEUDORABIES VIRUS EARLY PROTEIN-0 TRANSACTIVATES THE VIRAL GENE PROMOTERS

Pseudorabies virus (PRV) early protein O (EPO) contains the RING finge r domain with homology to the immediate-early (IE) protein ICPO of her pes simplex virus type 1 (HSV-1). EPO was detected by indirect immunof luorescence in the nuclei of the cells transfected with EPO expression plasmid as is the case in cells infected with PRV. In transient expre ssion assays, EPO transactivated the PRV IE, thymidine kinase (TK) and glycoprotein X (gX) promoters, indicating that EPO, like ICPO of HSV- 1, is a transactivating protein.