Figure 3.

Effect of Sox2 plus Oct-3/4 overexpression on the Sox2 and FGF-4 promoters. Schematics of each of the promoter/reporter constructs are shown. The gray boxes indicate critical enhancers, the basal promoter is represented by a black box adjacent to the CAT reporter gene, and the relative HMG/POU cassette is indicated with an asterisk. F9 EC cells were transfected with 12 µg of either (A) Sox2 + US/DSE or (B) FGF-4 + E plus 1 µg of the CMV-β-gal expression vector. Where indicated, 1, 2 or 3 µg of the Sox2 and/or the Oct-3/4 expression vector was co-transfected. Reporter activity was normalized to that of β-galactosidase and the activity of the reporter construct (with no overexpression) was set to 1. Overexpression values are shown relative to the given promoter/reporter construct. The data shown represents the mean and standard deviation of duplicate samples from representative experiments. Each experiment was repeated twice and similar results were obtained.