Preferential synthesis of viral late RNA by nuclei isolated from SV40 lytically infected cells.

Nuclei from SV40-infected monkey cells were isolated late in lytic infection and their cell-free transcriptional activity was characterized. 3H-RNA synthesized in vitro was hybridized to excess quantities of separated SV40 DNA strands which were each covalently bound to Sepharose. It was found that 3-5% of the newly synthesized RNA is virus-specific and that the plus-strand DNA, coding for late RNA sequences, is transcribed at a rate about 15 times higher than that of the minus-strand DNA, which codes for early RNA sequences. This indicates that transcriptional control has a major role in determining the relative abundancy of early and late RNA classes in lytically infected cells.