Fig. 8. Recruitment of p300/CBP by SRC2 enhances ER-mediated transcription initiation, but not reinitiation, with chromatin templates. The transcriptional activity of ERα and Gal4–SRC2(PID) (A and B), as well as the inhibitory activity of the GST–coactivator polypeptide fusions shown in Figure 3 (C), were analyzed in single round (+Sarkosyl) versus multiple round (–Sarkosyl) transcription experiments with chromatin templates. The number of rounds of transcription obtained was determined by dividing the amount of transcription in the absence of Sarkosyl by the amount of transcription in the corresponding sample in the presence of Sarkosyl. In (C), the GST polypeptides were added at a 50-fold molar excess relative to ERα. ‘ERα + E₂’ for each set of samples (±Sarkosyl) was set to 100%. Each bar represents the mean plus the range from two separate determinations.