FIGURE 3.

Transactivation of CYP2B6 5′-flanking reporter constructs by C/EBPα, HNF4α, and CAR. Sequential deletion fragments of the 5′-flanking region of the CYP2B6 promoter were cloned into the firefly luciferase pGL3-Basic reporter vector. HepG2 cells were infected with the three adenoviral vectors individually (A) or combined (B). Twenty-four hours later, cells were transfected with the different CYP2B6 promoter constructs (0.5 μg) and the normalization plasmid pRL-SV40 (0.08 μg). At 48 h postinfection, cells were treated with 500 nm CITCO, and at 72 h postinfection, cells were lysed, and both firefly and Renilla reniformis luciferase activities were determined. Bars, mean ± S.D. of five independent experiments, expressed as firefly/Renilla luciferase activity ratios. The symbols in the left-hand diagrams denote OA-responsive module (ellipse), PBREM (square), and XREM (hexagon).