A heteroduplex template circumvents the energetic requirement for ATP during activated transcription by RNA polymerase II.

Unlike most eukaryotic and prokaryotic RNA polymerases, promoter-specific transcription by RNA polymerase II requires hydrolysis of the ATP beta-gamma phosphoanhydride bond. Here we show that a template containing a 10-base pair DNA mismatch encompassing the start site circumvents this requirement such that the non-hydrolyzable ATP analogues, ATP gamma S (adenosine 5'-O-(thiotriphosphate)) and AMP-PNP (adenyl-5'-yl imidodiphosphate), support both basal and GAL4-VP16-activated transcription in a reconstituted HeLa cell in vitro transcription system. The results imply that ATP regulates either opening of the template at the start site or a closely associated step.