VARICELLA-ZOSTER VIRUS GENE-51 COMPLEMENTS A HERPES-SIMPLEX VIRUS TYPE-1 UL9 NULL MUTANT

Varicella-zoster virus (VZV) gene 51 encodes a protein which is homolo gous to UL9, the origin of DNA replication binding protein of herpes s implex virus type 1. No genetic information is available on VZV gene 5 1, but its product has been shown to bind to virtually the same recogn ition sequence as does UL9 (D. Chen and P.D. Olive, J. Virol. 68:3841- 3849, 1994; N. D. Stow, H. M. Weir, and E. C. Stow, Virology 177:570-5 77, 1990). We report here that gene 51 can complement a UL9 null mutan t (hr94) (A. K. Malik, R. Martinet, L. Muncy, E. P. Carmichael, and S. K. Weller, Virology 190:702-715, 1992), but at a level which is only 20% of that of UL9. Quantitation of viral DNA synthesis suggests that this phenotype is due to a defect in viral DNA synthesis. Regardless, the ability of VZV gene 51 to complement UL9 suggests that alphaherpes viruses have a highly conserved mechanism of initiation of viral DNA s ynthesis.