Figure 4.

Pre-initiation complex (PIC) formation at the HIS4 promoter was monitored in an immobilized template assay. Bead bound templates were incubated with yeast whole-cell extract in the presence of the TFIIB aptamers B60 or B4 at 50 nM for 30 min. The templates were then washed and promoter bound factors were analyzed by western blots using specific antibodies [anti-TFIIB, anti-Rpb3 (PolII), anti-TBP and anti-Toa2 (TFIIA)]. The results were quantified and the values normalized to the no aptamer sample are plotted. Error bars represent the SEM for three independent experiments.