PICH formation from PBMC nuclear extracts depends on general transcription factors. EMSAs were performed with PBMC nuclear extracts as in Figure 2. (A) The indicated antibodies were added to the reaction (lanes 2 to 6 and 8 to 11). Lanes 1 and 7 contain no antibody. Pre-initiation Complexes of HIV (PICHs), other complexes and a non-specific complex are indicated by arrows at the left. Black arrowheads highlight supershifted bands. Brackets point out smearing of bands. White arrowheads highlight bands lost upon antibody addition. (B) Quantification of EMSA band intensities from panel A. Band intensities are expressed on the Y-axis as a percentage relative to the strongest band in the control lane (panel A lane 1 or 7) that was set at 100%. The graph on the left corresponds to lanes 1 to 6, and the graph on the right to lanes 7 to 11. Band intensities that change by one third (33%) or more relative to its level in the control lane (−) are highlighted in orange. Complexes are displayed on the right (Z-axis), supershifting antibodies on the left (X-axis). Shades of grey are used to distinguish each PICH.