FIGURE 1.
A p53·p21waf1 promoter complex is destabilized by the yeast 26 S proteasome. A, schematic diagram of the biotinylated DNA fragments containing the p53 binding site (S) derived from pWAFMLT (i.e. the distal p53 binding site originally from the human p21waf1 gene) and containing no p53 binding site (NS), which was prepared by XbaI digestion of above fragment. The p53 binding site, TATA box, and transcription start site are indicated. B, Western blot using anti-p53 antibody that measures the amount of p53 protein that remains bound to the immobilized DNA after incubation for 15 min at 30 °C in the presence of the reagents indicated. The values shown at the bottom, which represent the percentage of p53 that remained bound to the immobilized DNA relative to the control lacking the proteasome and ATP (lane 1), were determined by quantitating each band using ImageJ software. C, the comparison of the destabilization effect of proteasomal ATPases on sequence-specific versus non-sequence specific p53 binding to the DNA.