Fig. 4.

Role of FOXO3a CR2C and CR3 and two KIX binding sites in luciferase transactivation. (A) HEK 293T or p300-null HCT116 cells were transfected with vector encoding luciferase fused to five GAL4 binding sites and pCMX vector encoding GAL4 DBD fused to CR2C-CR3, as well as to vector encoding p300 [WT or p300 lacking TAZ1 and KIX domains (p300ΔN); lacking TAZ2 (p300ΔC); or bearing mutations in the KIX MLL site, c-Myb site, or both). Luciferase activity was normalized to the cells overexpressing WT-p300 for each cell line. Significant differences (determined by ANOVA) are indicated. *P < 0.01. (B) HEK 293T cells were transfected with luciferase vector (as above), and vectors encoding GAL4 DBD were fused to CR2A-CR2B or to WT or mutant CR2C, CR3, or CR2C-CR3 fusion as indicated (Left). The four CR2C-CR3 fusions were also assayed in the presence of overexpressed p300. Luciferase activity was normalized to cells overexpressing GAL4 DBD alone. *P < 0.01; **P < 0.05. All experiments were repeated three times, and the data are shown as mean ± SEM.