Fig. 3. Associations of Smad1, ß-catenin and Tcf4 with the Myc promoter are enhanced in TgAlk3^QD kidney tissue. (A) Schematic representation of mouse Myc promoter. The 1409 nucleotide region upstream of the transcription start site is organized into Tcf-binding element (TBE), TBE-A, consisting of three Tcf-binding consensus sequences, an adjacent Smad-binding element (SBE), SBE-A, consisting of five Smad-binding consensus sequences, and a second SBE, SBE-B, consisting of four Smad-binding consensus sequences. (B) Results of ChIP. DNA amplified using region-specific primers is shown above graphs demonstrating quantitation of corresponding amplified DNA controlled for the amount of input DNA. Antibody controls using non-immune sera are shown for each ChIP. Left panel: ChIP of TBE-A using anti-Tcf4 antibody showing increased association of Tcf4 with TBE-A in TgAlk3^QD kidney tissues versus wild type. Middle and right panels: ChIP of SBE-A and SBE-B using anti-Smad1 antibody showing increased association of Smad1 with SBE-A and SBE-B in TgAlk3^QD kidney tissue. (C, left panels) ChIP of SBE-A using anti-Tcf4 antibody showing association of Tcf4 with SBE-A in TgAlk3^QD kidney tissue but not in wild-type tissue. (C, right panels) ChIP of SBE-B using anti-Tcf4 antibody. No association of Tcf4 with SBE-B was detected in either wild-type or TgAlk3^QD kidney tissue.