Abstract
Purified nuclei, isolated from appropriately infected HeLa cells, are shown to synthesize large amounts of either herpes simplex virus (HSV) or vaccinia virus DNA in vitro. The rate of synthesis of DNA by nuclei from infected cells is up to 30 times higher than the synthesis of host DNA in vitro by nuclei isolated from uninfected HeLa cells. Thus HSV nuclei obtained from HSV-infected cells make DNA in vitro at a rate comparable to that seen in the intact, infected cell. Molecular hybridization studies showed that 80% of the DNA sequences synthesized in vitro by nuclei from herpesvirus-infected cells are herpesvirus specific. Vaccinia virus nuclei from vaccinia virus-infected cells, also produce comparable percentages of vaccinia virus-specific DNA sequences. Adenovirus nuclei from adenovirus 2-infected HeLa cells, which also synthesize viral DNA in vitro, have been included in this study. Synthesis of DNA by HSV or vaccinia virus nuclei is markedly inhibited by the corresponding viral-specific antisera. These antisera inhibit in a similar fashion the purified herpesvirus-induced or vaccinia virus-induced DNA polymerase isolated from infected cells. Phosphonoacetic acid, reported to be a specific inhibitor of herpesvirus formation and the herpesvirus-induced DNA polymerase, is equally effective as an inhibitor of HSV DNA synthesis in isolated nuclei in vitro. However, we also find phosphonoacetic acid to be an effective inhibitor of vaccinia virus nuclear DNA synthesis and the purified vaccinia virus-induced DNA polymerase. In addition, this compound shows significant inhibition of DNA synthesis in isolated nuclei obtained from adenovirus-infected or uninfected cells and is a potent inhibitor of HeLa cell DNA polymerase alpha.