Figure 2.

Repression of LDLR promoter activity by PGC-1α that co-activates the ERα/ERE-dependent transcription. HepG2 cells were transfected with LacZ expression vector (400 ng), expression vectors (400 ng) for PGC-1α and/or ERα, and a reporter gene (800 ng), pERE-luc (panel A) or pLR1563-luc (panel B), as indicated. The cells were treated for 24 h with either vehicle only (EtOH, ethanol) or 17β-ethinyl estradiol (E₂, 10^-8 M) in phenol red-free MEM with 10% charcoal-treated FBS and harvested for luciferase assay. Normalized luciferase expressions from triplicate samples were calculated relative to the LacZ expressions, and the results were expressed as n-fold activation or % control over the value obtained with the reporter alone in EtOH. Values are mean ± SD of three independent duplicate experiments. ^*: P < 0.05 vs. the vehicle-treated.