Rexinoid effects on CAR/RXR are dependent on response element. A. HepG2 cells were cotransfected with expression constructs for CAR and/or RXR together with a previously described luciferase construct containing a ER-6 type element from the, human CYP3A4 promoter  in the presence or absence of ligands. The luciferase activity presented above is relative to that directed by vector alone in the absence of ligands (100%). B. A similar transfection with a previously described reporter containing the tandem DR-4 elements from the mCYP2B10 gene .