FIGURE 6.

SIRT1 decreases occupancy of SREBP-1c at the Fas and Srebp-1c gene promoters. A, HepG2 cells were transfected with plasmids, as indicated, using electroporation, and association of SREBP-1c or RNA pol II at the Fas and Srebp-1c promoters was detected by ChIP assays. B, the mRNA levels of Fas and Srebp-1c genes were detected by quantitative RT-PCR in parallel. Statistical significance was determined by Student's t test. *, p < 0.05 (n = 3). C, the experimental procedure is outlined. D and E, HepG2 cells were transfected with SREBP-1c wild type or mutant plasmids using electroporation as indicated. Cells were treated with insulin (100 nm) for 30 min and collected for ChIP assays to detect occupancy of SREBP-1c at the Fas promoter (D), Srebp-1c promoter (F), or GAPDH coding region (E). Consistent results were observed from two independent assays. IP, immunoprecipitation. Error bars, S.E.