Figure 6. Foxo1 participates in the insulin inhibition of PDK4 gene expression.

A. The FoxO1 site in the −1529/+78 site in the PDK4 promoter was disrupted by site directed mutagenesis. The mutant vector was transfected into McA cells with ERRα and PGC-1α as described in the legend to figure 4. Transfections were repeated four times in duplicate. B. Primary rat hepatocytes were treated with dexamethasone or insulin for 4 hours prior to crosslinking with 1% formaldehyde. Chromatin immunoprecipitation (ChIP) assays were conducted with the PDK4 promoter and an antibody to FoxO1 essentially as described in the legend to figure 2. C. The PCR products were quantified as described in the materials and methods. The values represent the average of four independent preparations of hepatocytes.