Kilham rat virus DNA replication in subcellular fractions.

A subcellular system actively replicating Kilham rat virus DNA in vitro was developed. Cellular lysates and isolated nuclei from infected cells showed an amplification of replicative forms in vitro. Solubilized replicative complexes, either partly purified or in the form of a crude extract, were able to synthesize replicative forms and single-stranded DNA. DNA polymerase alpha played a major role in Kilham rat virus DNA synthesis in vivo and in vitro. Furthermore, a factor present in the cytosol of infected cells increased the polymerizing activity of viral replicative complexes.