Figure 4.
Permanganate mapping of open transcription bubbles reveals engaged Pol II within the promoter-proximal region of genes with PPEP. In vivo permanganate footprinting demonstrates the presence and locations of engaged Pol II in the promoter-proximal region of five genes with PPEP. Each panel shows a adenine-guanine ladder used for position determination, the reactivity pattern of naked DNA as a control and the permanganate reactivity observed in S2 cells (last lane in each panel). The positions of a subset of hyper-reactive thymine residues are identified to the right of each panel.