Induction of host DNA synthesis and DNA polymerase by DNA-negative temperature-sensitive mutants of human cytomegalovirus

Abstract

Four DNA-negative temperature-sensitive ( ts) mutants of human cytomegalovirus, belonging to different complementation groups, were studied for their ability to induce cell DNA synthesis and DNA polymerase in permissive human embryo lung (HEL) and nonpermissive rabbit lung (RL) cells. These is mutants stimulated host cell DNA synthesis in HEL and RL cells and DNA polymerase activity in HEL and RL cells at permissive (33.5°) and nonpermissive temperatures (39.5°). Salt stimulation of induced DNA polymerase activity was used to distinguish between virus and cell DNA polymerase from HEL cells. DNA polymerase activity was stimulated by 100 m M (NH 4) 2SO 4 at either 33.5 or 39.5° in cultures infected with three of the mutants ( ts 9, is 153, and ts 155). However, DNA polymerase activity was not stimulated by 100 m M (NH 4) 2SO 4, in cultures infected with one of the ts mutants ( ts 13). These data suggest that at least four cistrons control the synthesis of virus DNA and that virus DNA synthesis is not required for the induction of cell DNA synthesis.