Symmetric transcription of simian virus 40 DNA in the nuclei of transformed mouse cells

Abstract

The transcription pattern of SV40 DNA in the transformed mouse 3T3 cell line SV101 has been determined by DNA-RNA hybridization studies using the separated strands of restriction endonuclease derived viral DNA fragments as molecular probes. RNA isolated from the cytoplasm of these cells contained asymmetrically transcribed base sequences complementary to only the early region of the viral genome, while RNA isolated from purified nuclei contained symmetrically transcribed sequences complementary to all regions. The presence of late, anti-early, and anti-late RNA copies in the nuclei of these transformed cells, and their absence from the cytoplasm, suggests that RNA processing and/or transport are significant control mechanisms in the expression of this eukaryotic DNA.