The Herpes Simplex Virus Type 1 UL8 Protein Influences the Intracellular Localization of the UL52 but not the ICP8 or POL Replication Proteins in Virus-infected Cells

MRC Virology Unit, Church Street, Glasgow G11 5JR, UK Author for correspondence: H. S. Marsden. Fax +44 141 337 2236, e-mail H.Marsden{at}vir.gla.ac.uk We have developed a panel of 14 monoclonal antibodies (MAbs) to POL, the catalytic subunit of herpes simplex virus type 1 (HSV-1) DNA polymerase encoded by gene UL30, and one MAb to the UL52 protein, another of the seven proteins essential for replication of HSV DNA. The approximate locations of the epitopes of the polymerase-specific MAbs were identified using truncated polymerase molecules, and the antibodies were characterized in a number of immunological assays allowing eight different specificities to be recognized. These MAbs, together with a polyclonal antibody raised in rabbits against a third DNA replication protein, ICP8, were used to localize the respective proteins by immunofluorescence in cells infected with wild-type HSV-1 or the DNA replication-defective mutants amb UL8 or 2-2. In BHK cells infected with amb UL8, a mutant with an amber termination codon within the coding region of gene UL8, the UL52 protein did not enter the nucleus, although ICP8 and POL entered the nucleus in a normal fashion. The failure of the UL52 protein to be correctly transported to the nucleus was also observed in both HFL and Vero cells infected with amb UL8. In contrast, UL52 protein was transported to the nucleus in BHK cells infected with wild-type HSV-1 or with 2-2, a mutant lacking a functional UL9 protein. Present address: MRC AIDS Reagent Project, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts EN6 3QG, UK. Received 1 April 1996; accepted 4 June 1996.