Figure 3.

The recruitment of Smad2/4 and PIAS1 complex to the P21^WAF1/Cip1 promoter induced by zinc. (a) Schematic diagram of three SBEs of the p21^WAF1/Cip1 promoter. (b) ChIP assays of Smad4 or Smad3 occupancy on the p21^WAF1/Cip1 promoter in LNCaP cells with or without zinc treatment. LNCaP cells were used with or without zinc treatment, and anti-Smad4, anti-Smad3 or IgG antibody was added to immunoprecipitate chromatin and the elution was analyzed by p21 promoter-specific primers. (c) Re-ChIP assays of Smad4/Smad2 complex occupancy on the p21^WAF1/Cip1 promoter in cells with or without zinc treatment. (d) Re-ChIP assays of Smad4/PIAS1 complex occupancy on the p21^WAF1/Cip1 promoter in cells with or without zinc treatment. LNCaP cells were used with or without zinc treatment and mouse anti-Smad4 or IgG antibody was added to immunoprecipitate chromatin. The elution was subjected to a second immunoprecipitation by anti-Smad2, anti-Smad3 or IgG antibody (c), or by anti-PIAS1, PIAS2, PIAS3 or IgG antibody (d). The final elution was analyzed by p21 promoter-specific primers