Figure 6.

Tip60 is required for p53 binding on p53 target promoters. U2OS cells were transfected by the indicated siRNAs (C1 or Tip1) by electroporation and 48 h later, they were UV-irradiated or not (10 J/m²). After 16 h irradiation, ChIP was performed on these cells using an anti-p53 antibody (black bars) or no antibody as a control (grey bars). The presence of p21 promoter, fas promoter (containing the p53 response element) and β-actin coding sequence in the immunoprecipitates and in the inputs were analysed by real-time PCR. After dividing by the input DNA, the amount of immunoprecipitated sequence was calculated relative to 1 for the amount of p21 promoter immunoprecipitated by the anti-p53 antibody in cells transfected by the control siRNA and not irradiated. The mean and standard deviation from three entirely independent experiments are shown.