RNA synthesis in isolated nuclei: in vitro initiation of adenovirus 2 major late mRNA precursor.

We have analyzed the RNA produced in vitro by incubating nuclei from HeLa cells infected with adenovirus serotype 2. Our results show that adenovirus-specific RNA is produced at a linear rate for up to 2.5 hr. Hybridization analysis of RNA produced in nuclei isolated 18 hr after infection indicated that transcription begins at the "late promoter" at map position 16.5. Sequence analysis of the 5' termini of the in vitro transcripts showed that this system initiates RNA chains de novo at the correct promoter and that the 5' terminus is capped.