Fig. 7. Acetylation by PCAF stimulates rDNA transcription in vitro. (A) PCAF-mediated transcriptional activation. Transcription factors and Pol I were pre-incubated in the absence (lane 1) or presence of 60 (lanes 2 and 4) and 160 ng (lanes 3 and 5) of purified GST–PCAF. Reactions 4 and 5 were supplemented with 10 µM acetyl-CoA. After pre-incubation for 30 min at 30°C, transcriptions were started by adding 20 ng of template DNA and ribonucleotides. (B) Transcriptional stimulation by PCAF requires a functional HAT domain. Transcription reactions were performed in the absence (lane 1) or presence of GST–PCAF (lanes 2 and 3) or GST–PCAF/ΔHAT (lanes 4 and 5) and 10 µM acetyl CoA as above.