STUDY ON SIMIAN-VIRUS-40 DNA-SYNTHESIS IN HERPES-SIMPLEX VIRUS-INFECTED CELLS

Replication of simian virus 40 (SV40) DNA occurs in SV40 nonpermissive hamster cells upon infection with herpes simplex virus (HSV), leading to concatemeric replication products characteristic for HSV DNA repli cation. This SV40 origin (ori)-dependent process is governed by SV40 l arge T antigen and HSV-encoded DNA replication factors; e.g., DNA poly merase, single-strand binding protein (SSB), and helicase-primase. In this study, we show that specific interaction of SV40 T antigen with S V40 ori is crucial for HSV-directed SV40 DNA synthesis and that the pr operty of T antigen to bind and unwind the ori is not sufficient for t his process. A T antigen with the mutation T217S, affecting a hypothet ical novel DNA replication subfunction, is able to support DNA synthes is in vitro but not in cultured primate cells. This subfunction is als o necessary in HSV-infected hamster cells. Using temperature-sensitive mutants, we demonstrate that the T antigen acts at early stages of DN A synthesis while HSV helicase is required continuously as has been sh own for HSV DNA polymerase. HSV SSB is also continuously involved in h eterologous SV40 DNA synthesis. However, a HSV mutant, temperature-sen sitive in SSB function, showed residual synthesis of SV40 DNA but not of HSV DNA at the nonpermissive temperature. The nature of this dichot omy between HSV SSB function on SV40 DNA and HSV DNA will be discussed . (C) 1996 Academic Press, Inc.