FIG. 7.

Dose-dependent activation of the LXRE complex enhancer in the SREBP-1c promoter by LXRs (left panel) and their ligands (right panel). The LXRE complex (LXREa and -b, bp −249 to −148) in the SREBP-1c promoter was fused to a luciferase reporter plasmid which contained a simian virus 40 promoter (pGL2 promoter vector; Fig. 5) to estimate LXRE enhancer activity (pLXRE-Luc). (Left panel) pLXRE-Luc was cotransfected into HEK 293 cells with pCMV-LXRα, pCMV-LXRβ, or an empty vector (CMV-7, used as a control) and pSV-βgal, which was used as a reference plasmid. (Right panel) Ligands for LXR or ethanol (used as a control) was added to the cells after transfection of pLXRE-Luc and pSV-βgal 24 h prior to the assay. After the incubation, luciferase activity was measured and normalized to β-galactosidase activity. Fold induction of luciferase activity by LXRs or their ligands (means ± standard deviations in the left panel [n = 3]; means in the right panel [n = 2]) compared to that of the control is shown. Cho, cholesterol.