ChIP assays demonstrating protein binding at the IGF2 promoter region. (A) A schematic diagram of the IGF2/H19 imprinting domain. The exons are depicted as solid boxes. The bottom arrows mark the orientation of ChIP-specific primers. (B and C) Alteration of CTCF binding, SUZ12 interaction, and histone H3-K27 methylation across IGF2 promoters in decoy CTCF ZF-Sss1–expressing MCF7 breast tumor cells (B) and HBF1 fibroblasts (C). Cross-linked DNA–protein complexes were immunoprecipitated with antiserum against CTCF, SUZ12, or dimethyl-H3-K27 (mK27), followed by PCR amplification with specific primers for the IGF2 promoters (P1–P4). Input: genomic DNA collected before antibody precipitation.