Characterization of early simian virus 40 transcriptional complexes: late transcription in the absence of detectable DNA replication.

Abstract

Isolation of early viral transcriptional complexes and incorporation in vitro of radiolabeled precursors into nascent RNA permitted an analysis of early SV-40 transcription. Under conditions such that viral DNA replication was undetectable, both early and late SV-40 RNA were synthesized. Apparently, viral DNA replication is not an absolute requirement for late transcription, and late viral RNA is synthesized in SV-40 infected nonpermissive mouse cells. The majority of the early viral transcriptional activity can be solubilized, indicating that a substantial portion of this RNA is transcribed from free rather than integrated templates. Sedimentation analysis of the transcriptional complexes resulted in the detection of 2 separate peaks of activity, suggesting the possibility of 2 distinct types of early SV-40 templates.