Figure 3.
Effect of FoxO1 on islet mRNA expression in FoxO1-transgenic mice on high-fat diet. FoxO1-tg and WT littermates (male, 8 wk old, n = 10/group) were killed under fasting conditions after 8 weeks of high-fat feeding. Islets were subjected to real-time qRT-PCR analysis using 18S RNA as control. A, Islet mRNA profiles of genes in cell-cycle G1/S transition. B, The mouse Ccnd3 promoter. Underlined are nucleotides corresponding to the consensus FoxO1 binding site. C, ChIP assay for FoxO1-Ccnd3 promoter interaction. D, Ccnd3 promoter activity in INS-1 cells, as determined by luciferase reporter assay; n = 3. E, Ccnd3 protein levels. Aliquots of islets (n = 150/mouse) from high-fat-fed FoxO1-tg and WT littermates (n = 3/group) were subjected to anti-Ccnd3 immunoblot analysis, using anti-β-actin as control. The amounts of Ccnd3 relative to β-actin proteins in islets were determined. F, Islet mRNA profiles of genes in β-cell mass and function regulation. *, P < .05 and **, P < .005 vs WT control.