Research Article

Identification of Sp1 as a Transcription Activator to Regulate Fibroblast Growth Factor 21 Gene Expression

Figure 5

Sp1 can induce the upregulation of FGF21 in liver of DEN-treated mice. (a) Histochemical analysis of liver samples from mice treated with DEN or PBS. Liver tissues were collected at 4 months after injection and then fixed overnight in 4% PFA in 1x PBS. Paraffin-embedded tissue blocks were sectioned into 5 μm slides for H&E staining. (b) Western blot analysis of FGF21 and Sp1 protein levels in the liver of C57BL/6J mice injected with PBS or DEN for 4 months. Quantification of the relative protein levels (expressed as the percentage of PBS-treated mice protein level, arbitrarily set as 1.0) was performed by analyzing Western blot data from three independent experiments using the Scion Image program. Actin was used as a loading control. Data are means ± SEM, . versus PBS-treated mice. (c) ChIP analysis. Formaldehyde-crosslinked chromatin from liver of C57BL/6J mice treated with PBS or DEN was incubated with anti-Sp1 antibody. DNA immunoprecipitated using the antibody against Sp1 was analyzed by PCR with primers specific for the FGF21. Input DNA were used as a positive control for the PCR reaction. The chromatin incubated with nonspecific IgG and diethylpyrocarbonate-treated water (DEPC H2O) were used as negative control.