The definition of a large viral transcription unit late in Ad2 infection of HeLa cells: mapping of nascent RNA molecules labeled in isolated nuclei.

Nuclei isolated from HeLa cells 15 hr after infection with Ad2 synthesize an RNA transcript approximately 25 KB long, beginning between 0.2 and 0.3 on the physical map and extending to (or close to) the right end of the genome. The majority (60-92%) of the RNA transcribed from fragments between 0.2 and 1.0 is synthesized as part of this large molecule which represents the major product of late Ad2 RNA synthesis. Smaller transcripts are also formed mainly from the left end of the Ad2 genome.