Figure 2.

Activation of the wild-type and mutant LDL receptor promoter by SREBP-1a and Sp1. Drosophila SL2 cells were transfected with increasing amounts of pPACSREBP-1a DNA alone (□, ○) or in the presence (▪, •) of a constant amount (25 ng/60-mm dish) of pPACSp1 expression vectors as indicated. The wild-type (Wt; •, ○) or mutant (LDLE; ▪, □) LDL receptor promoter fused to the luciferase gene (2 μg per 60-mm dish) were used as the reporters. Transfection, harvesting, preparation of cell extracts, and enzyme assays were performed as described in Materials and Methods. A pPAC-β-galactosidase expression vector (1 μg per 60-mm dish) was included in all transfections and its expression was used for normalization of the luciferase activity. This graph represents data from one of three individual experiments that showed similar results.