FOXO induces TR4 promoter activity. A, Schematic representation of TR4 promoter. Putative FOXO consensus binding site and potential cobinding site locations and sequences are shown. B, H1299 cells were transfected with 500 ng pGL-TR4–1920 and 200 ng vector, FOXO3a, FOXO3a-TM, FOXO4, or FOXO4-T451E. After 48 h, cells were harvested and Luc activities were measured. **, P < 0.01 (ANOVA), as compared with vector or FOXO3a WT. C, Schematic diagram of 5′ serial deletions and site-directed mutagenesis of TR4 promoter reporter constructs (left panel); 500 ng pGL3 and indicated TR4 promoter reporter constructs were cotransfected with 200 ng FOXO3a-TM or vector into H1299 cells. After 48 h, cells were harvested and Luc activities were measured. **, P < 0.01 (ANOVA), as compared with vector or FOXO3a-TM upon pGL3, pGL-TR4–605 or pGL-TR4–1920m.