FIGURE 8.

FOXO3a activates transcription from its own promoter. A, schematic representation of the Foxo3a promoter regions cloned into firefly luciferase reporter vector. The locations of potential FHREs 1–4 are indicated with black boxes. Mutated FHRE 3 is depicted as a white box. The numbers indicate the position relative to the transcription start site (TSS) that is shown with arrows. B–D, reporter assays with primary cortical neurons (B), Hdh^7/7 (C), and Hdh^109/109 cells (D) transfected with Foxo3a promoter constructs and Renilla luciferase construct with EF1α promoter (B) or PGK1 promoter (C and D) for normalization. The cells were co-transfected with constructs encoding constitutively active Flag-FOXO3A-TM or empty vector. Luciferase activities were measured, and data are presented as fold induction of normalized luciferase activity in Flag-FOXO3A-TM-expressing cells compared with cells transfected with empty vector. The statistical significance denoted with asterisks is relative to the induction of transcription from WT full-length promoter. *, p < 0.05; **, p < 0.01; ***, p < 0.001; n > 3