Possible involvement of pregnane X receptor–enhanced CYP24 expression in drug-induced osteomalacia
J. Clin. Invest. Jean Marc Pascussi, et al. 115:177 doi:10.1172/JCI21867 [Go to this article.]

Figure 5
PXR transactivates the proximal human CYP24 promoter. (A) VDREs present in the human CYP24 (hCYP24) gene. Schematic representation of the human CYP24 constructs used in this work. (B) Ligand-activated PXR transactivates the –326 to –143 promoter region of human CYP24. Hek293 cells were transiently transfected with human PXR (pSG5-Ø^ATG-hPXR), mouse PXR (pSG5-mPXR), or control expression vector (pSG5) in the presence of reporter vectors driven by the indicated human CYP24 promoter sequences, together with pRSV-β-gal transfection control plasmid. Cells were treated with vehicle (0.1% DMSO; UT), 50 nM 1α,25(OH)₂D₃ (VD₃), 10 μM rifampicin (RIF), or 10 μM pregnenolone 16α-carbonitrile (PCN) for 24 hours. Cells were then harvested and analyzed for both luciferase and β-gal activities. Values represent β-gal–corrected luciferase activities normalized to the corresponding level in untreated Hek293 cells and are the average of duplicates ± SE. These were replicated in independent experiments.