End group of naturally terminated and UV lesion terminated T7 in vitro RNA.

The 3' terminal nucleosides of RNA transcribed in vitro by E. coli RNA polymerase from T7 DNA and UV irradiated TN DNA were determined. The 3' terminal nucleoside of naturally terminated (t1 termination site) RNA cytidine. In the case of RNA terminated at UV lesions, it is cytidine in 0 per cent of the molecules and adenosine in the remaining 30 per cent. Cytidine trialcohols are labile in high concentrations of KOH and at high temperature and appear to convert to uridine.