FIGURE 3.

SOX9 transcriptionally activates TCF4 by binding to the TCF4 promoter. A, ChIP assay using three independent SOX9-specific antibodies (Ab1–3) was performed in MCF10A-DCIS cells. P1 and P2 are PCR fragments of the promoter region, whereas C1 and C2 are PCR fragments of exon or intron region (numbered from the translation initiation site). B, MCF7 cells were transfected with a TCF4 promoter-driven firefly luciferase reporter and a CMV-driven Renilla luciferase reporter together with increasing quantities of SOX9 expression vector or empty vector control. The luciferase activities were assessed at 72 h posttransfection. RLU, relative light unit (the ratio of firefly over Renilla luciferase light units; n = 3). Error bars show S.E.