Effects of cytosol on transcription in isolated simian-virus-40-infected nuclei

The transcription in vitro of nuclei isolated from monkey kidney cells infected with simian virus 40 was stimulated by a cytosol fraction from the same uninfected cells. Transcription in nuclei was inhibited 60--80% by 0.1 microgram/ml of alpha-amanitin, in the presence or in the absence of the cytosol preparation. Treatment of nuclei after transcription in vitro with 0.02 M EDTA preferentially solubilized viral-specific RNA partially bound to the viral chromatin. The increase in incorporation into total RNA seen in the presence of cytosol was not paralleled by any detectable increase in transcription of viral sequences as shown by RNA . DNA hybridizations.