L. Gaudreau et al., ACTIVATION OF TRANSCRIPTION IN-VITRO BY RECRUITMENT OF THE YEAST RNA-POLYMERASE-II HOLOENZYME, MOLECULAR CELL, 1(6), 1998, pp. 913-916
It has been argued that many transcriptional activators work by ''recr
uitment,'' that is, by helping the transcriptional machinery bind stab
ly to DNA. We demonstrate here a realization of a strong prediction of
this idea in an in vitro transcription reaction performed with purifi
ed yeast RNA polymerase II holoenzyme and a classical transcriptional
activator. We show that the level of transcription reached by the acti
vator working on low concentrations of holoenzyme can also be reached
in the absence of activator by raising the holoenzyme concentration, a
nd that under that condition the activator has no further stimulatory
effect. We also show, in agreement with another prediction of the recr
uitment model, that in a reaction using a holoenzyme purified from cel
ls bearing the ''P'' mutation, transcription is stimulated by a DNA-te
thered peptide that binds the mutant holoenzyme component Gal11P but t
hat lacks a classical activating region.