FIG. 5.

Identification of LXREs by deletional and mutational analysis of the oxysterol-inducible region in the SREBP1c-promoter. (A) DNA sequencing of the oxysterol-inducible region of the SREBP1c promoter identified two elements, which were designated mLXREa and -b. These elements are highly similar to the LXRE of the human ABC1 promoter. (B) Sequential deletion and mutation analysis of the oxysterol-inducible region was performed with reporter genes with the indicated sizes and positions of the promoter. HEK 293 cells were transfected with each reporter plasmid, pCMV-LXR, and reference plasmid pSV-βgal and thereafter cultured for 24 h in medium with 10% fetal bovine serum. Luciferase activity was measured and normalized to β-galactosidase activity. Fold induction of luciferase activity by LXRs (means ± standard deviations) is shown. SV40, simian virus 40.