FXR-mediated transreppression of Cyp8b1 and transcriptional activity of the FXR isoforms <i>in vitro.</i>

<p>Luciferase assays where performed in CV1 cells using an luciferase reporter containing tandem copies of the FXRE from the Cyp8b1 (A) and SHP (B) genes. Activity is shown in fold induction, with the transfection efficiencies being normalized using a dual Renilla-Firefly luciferase assay. Activity is compared to empty vector control. Using the SHP receptor, cells were treated 24 hr post transfection either with 50 µM CDCA or vehicle. Data are presented as average ± standard deviations (n≥2). Significance Cyp8B1 reporter: *p<0.05 <i>vs</i>. control; #p<0.05 <i>vs.</i> HNF4α 10 ng; $p<0.05 <i>vs</i>. HNF4α 100 ng; &p<0.05 <i>vs</i> HNF4α and SHP; ∧p<0.05 <i>vs</i>. HNF4α and FXRα2. Significance SHP reporter: *p<0.05 <i>vs</i>. control; #p<0.05 <i>vs</i>. FXRα1; $p<0.05 <i>vs</i>. FXRα2; &p<0.05 <i>vs,</i> FXRα3.