Figure 3

BHEXIM1 competes with BTat for binding B-cyclin T1. GST (lane 1, 20 μg) or GST-B-cyclin T1 (lane 2-6, 20 μg) was incubated with His-BTat (5 μg). Increasing amounts of His-BHEXIM1 (1, 5, 10, 20 μg) were added to the reactions in lane 3-6 but not lane 1 and 2. GST pulldown was then performed, and the purified GST and GST-B-cyclin T1 used in the pulldown assay were detected by Coomassie blue staining (top). The bound BTat and BHEXIM1 were detected using an anti-His antibody (middle). The amount of BTat and BHEXIM1 in the cell lysates were checked using an anti-His antibody (bottom).