Figure 8.

The Srebp1c promoter is regulated by DNA methylation during 3T3-L1 adipogenesis. A, DNA methylation levels were decreased at CpG sites on the key cis-elements of Srebp1c promoter during adipogenesis. 3T3-L1 preadipocyte were induced to differentiate and cells were harvested at day 0 or 8 of the differentiation for the pyrosequencing analysis, which was conducted as described in Materials and Methods. All data are expressed as mean ± SEM, n = 4; *, P < .05 vs D0. D0, day 0; D8, day 8. B, The binding of nuclear extracts to the fully methylated SRE oligonucleotides was decreased compared with the unmethylated SRE. The binding of nuclear extracts to SRE oligonucleotides was measured by EMSA, which was conducted as described in Materials and Methods. C, DNA methylation regulates Srebp1c promoter activity. A 550-bp Srebp1c promoter was cloned into the pGL3 luciferase reporter. Unmethylated vs fully methylated SREBP1C promoter activity was conducted as described in Materials and Methods. All data are expressed as mean ± SEM, n = 4; *, P < .05 vs methylated.