RNA-POLYMERASE-II HOLOENZYME RECRUITMENT IS SUFFICIENT TO REMODEL CHROMATIN AT THE YEAST PHO5 PROMOTER

We examine transcriptional activation and chromatin remodeling at the PHO5 promoter in yeast by fusion proteins that are thought to act by r ecruiting the RNA polymerase II holoenzyme to DNA in the absence of a classic activating region. These hybrid proteins (e.g., Gal11+Pho4 or Gal4(58-97)+Pho4 in the presence of a GAL11P allele) efficiently activ ated transcription and remodeled chromatin. Similar chromatin remodeli ng was observed at a PHO5 promoter deleted for TATA and thus unable to support transcription. We conclude that recruitment of the holoenzyme or associated proteins suffices for chromatin remodeling. We also sho w that the SWI/SNF complex is required neither for efficient transcrip tion of the wild-type PHO5 nor the GAL1 promoters, and we observe near ly complete chromatin remodeling at PHO5 in the absence of Snf2.