Figure 4.

Decoy CTCF Repeals the Histone Acetyltransferase EP300 at the SELL Promoter

(A) Schematic diagram of decoy-CTCF ChIP assay. Two kinds of CTCF protein antibody were used; one can recognize the N-terminal of CTCF (blue) and the other one can recognize the zinc-finger region (red). And the testing site of ChIP assay was shown on the bottom. (B and C) Semi-quantitative (B) and quantitative (C) ChIP assay demonstrated that CTCF could combine to the promoter of SELL in ocular melanoma cells. And decoy-CTCF transfection could reject this combination of wild-type CTCF. (D and E) Semi-quantitative (D) and quantitative (E) ChIP assay showed that EP300 was recruited to the promoter of SELL and lead to the H3K27ac modification at this region. Decoy-CTCF could abolish this recruitment and let down the H3K27ac modification level. (F) Coimmunoprecipitation (coIP) assays suggested that the wild-type CTCF could be pulled out by baiting the EP300 protein (panels 1–3), and EP300 could also be pulled out by baiting the CTCF protein (panels 4–6). Decoy-CTCF could not be detected to interact with Ep300 (panels 7–8).