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. 2009 Jul 16;23(10):1587–1602. doi: 10.1210/me.2008-0421

Figure 3.

Figure 3

The C termini of FoxO1 and FoxO3a are insulin-activated transcriptional enhancers. GH4 cells were electroporated with 10 μg of a Luciferase reporter plasmid containing six copies of the LexA response element (ColE1-Luc), 5 μg of pRT3HIR2, and 0.5 μg of rous sarcoma virus-β-Gal. A, Each electroporation also contained 10 μg of an expression vector for a fusion protein containing the LexA DNA-binding domain and the indicated Fox transcription factor C terminus (FoxO1, aa 236–655; FoxO3a, aa 233–673; FoxC1, aa 231–553; FoxC2, aa 231–493; and FoxP1, aa 2–706). A previously described LexA-Elk1 (aa 105–428) was used as a control. The cultures were incubated for 20 h with insulin or forskolin. The luciferase activity was determined and corrected for β-Gal expression as described in Materials and Methods. B, Each electroporation also contained 10 μg of an expression vector for a fusion protein containing the LexA DNA-binding domain and FoxO1 AAA mutant (aa 236–255) or FoxO3a AAA mutant (aa 233–673). The cultures were incubated for 20 h with insulin or forskolin. The luciferase activity was determined and corrected for β-Gal expression as described in Materials and Methods.