FIGURE 5.

Functional interaction between FXR and the SF-1 site. A, schematic map of the P450arom proximal promoter PII constructs used in this study. All of the promoter constructs contain the same 3′ boundary (+94). The 5′ boundaries of the promoter fragments varied from −1037 to −183. Three putative CRE motifs (5′-CRE at −335; 3′-CRE at −231; XCRE at −169) are indicated as squares. The AGGTCA site (SF-1 RE at-90) is indicated as a rectangle. A mutated SF-1 binding site (SF-1 mut) is present in p-688m (black rectangle). B, aromatase transcriptional activity of R2C cells transfected with promoter constructs are shown. After transfection, cells were treated in the presence of vehicle (−) or 50 μm CDCA for 24 h. These results represent the mean ± S.D. (error bars) of three different experiments performed in triplicate. *, p < 0.01 with respect to the vehicle; **, p < 0.01 with respect to the control of p688. C, HeLa cells were transiently cotransfected with the CYP17 promoter and SF-1 plasmid or empty vector (EV) in the presence of increasing amounts of FXR expression plasmid. These results represent the mean ± S.D. of three different experiments performed in triplicate. In each experiment, the activities of the transfected plasmids were assayed in triplicate transfections. *, p < 0.01 with respect to the EV; **, p < 0.01 with respect to the SF-1 alone.