Identification and characterization of the UL14 gene product of herpes simplex virus type 2

The UL14 gene of herpes simplex virus type 2 (HSV-2) is predicted to encode a 219 amino acid protein with a molecular mass of 23 kDa. In this study, the HSV-2 UL14 gene product has been identified by using a rabbit polyclonal antiserum raised against a recombinant 6 x His-UL14 fusion protein expressed in E. coli. The antiserum reacted specifically with 34, 33 and 28 kDa proteins in HSV-2-infected cell lysates and also with a 34 kDa protein produced by in vitro transcription and translation reactions, suggesting that the 34 kDa protein is the primary translation product of the UL14 gene. The protein was synthesized at late times post-infection (p.i.) and was not detectable in the presence of the viral DNA synthesis inhibitor acycloguanosine. Indirect immunofluorescence studies localized the UL14 protein both to the nucleus and to perinuclear regions of the cytoplasm, and the nuclear UL14 protein was found to co-localize with the scaffolding protein ICP35 at 9 h p.i. However, the protein accumulated in a perinuclear region of the cytoplasm at 12 h p.i., while most of the ICP35 protein localized within assemblons in the nucleus. Although no detectable UL14 protein was associated with intracellular capsids isolated in the presence of 0.5 M NaCl, it was detected in purified virions. Furthermore, the UL14 protein expressed alone was detected both in the nucleus and in the cytoplasm at 24 h after transfection, but was mainly localized to the cytoplasm at later times.