Fig. 5. Chromatin Immunoprecipitation assay demonstrates that HNF6 and Foxm1 proteins bind to the endogenous TGFα and Cyclin D1 promoter regions.

The mouse TGFα promoter region contains distinct DNA binding sequences for the HNF6 protein (−1608 to −1591 bp) and the FoxM1 protein (−1561 to −1531 bp), whereas these transcription factors bind to the same DNA sequence in the mouse Cyclin D1 promoter region (−1064 to −1049 bp). Mouse hepatoma Hepa1-6 cells were mock infected or infected with AdHNF6 or adenovirus expressing Green Fluorescent Protein (AdGFP). For the Cyclin D1 promoter ChIP assays (Panel D), we also infected Hepa1-6 cells with AdHNF6 or AdM1b (adenovirus expressing human FoxM1b) separately or together. At 24 hours after infection the chromatin was cross-linked, sonicated to DNA fragments of 500 to 1000 nucleotides in length, and then processed for ChIP assays as described in the Materials and Methods. The cross-linked and sonicated mouse chromatin was immunoprecipitated (IP) with antibodies specific to either HNF6 (+, A and B) or FoxM1 (+, C and D) or with rabbit antisera (−) and the amount of promoter DNA associated with the IP chromatin was quantitated by Real-Time PCR with primers specific to either the −1647 to −1495 bp mouse TGFα promoter region (A and C) or the −890 to −733 bp mouse Cyclin D1 promoter region (B and D). The asterisks indicate statistically significant changes: *P ≤ 0.05, **P ≤ 0.01 and P ≤ 0.001.