Figure 1.

Effect of DAF-16 homologs on insulin- and glucocorticoid-responsive gene transcription. HepG2 were cotransfected with a construct encoding the native IGFBP-1 promoter (10 μg/ml) driving luciferase gene expression and the pcDNA expression vector alone (1 μg/ml), or the expression vectors pcDNA⋅DAF-16, pcDNA⋅FKHR, pcDNA⋅FKHRL1, and pcDNA⋅AFX (1 μg/ml). In A, insulin (1 milliunit/ml) was added to serum-starved cells during the last 18 h of incubation. In B, cells were exposed to dexamethasone (0.5 μM) for 18 h. The effect of these agents on endogenous proteins, pcDNA (bars A and B), or the exogenous proteins encoded by pcDNA⋅DAF-16 (bars C and D) and its three mammalian homologs, pcDNA⋅FKHRL1 (bars E and F), pcDNA⋅FKHR (bars G and H), and pcDNA⋅AFX (bars I and J) is shown. Luciferase activity was corrected for β-galactosidase gene expression. The data shown are representative of three experiments.