The tumor suppressor p53 has been proposed to bind target promoters upon genotoxic stress. However, recent evidence shows that p53 occupies some target promoters without such stress, suggesting that a negative regulator might render p53 transcriptionally inactive on these promoters. Here we show that calcineurin binding protein 1 (Cabin1) is a negative… (More)
Figure 3 CABIN1 occupies a subset of p53 target promoters in the absence of genotoxic stress. (a) ChIP and re-ChIP show that CABIN1 and p53 coexist on the GADD45 promoter. (b) Recruitment of CABIN1 to the GADD45 promoter is dependent on p53 occupancy. HCT116 (TP53+/+) and HCT116 (TP53–/–) cells were ChIPed with anti-p53 or anti-CABIN1 antibodies. ChIPed DNA was analyzed by real-time qPCR. (c,d) CABIN1 occupies a subset of p53 target promoters. CABIN1 (c) and p53 (d) occupancy on various p53 target promoters in HCT116 cells was determined by ChIP assays. *P < 0.05.