FIGURE 5.

DNA binding domain of FOXO1 is required to suppress basal and GnRH-induced Lhb gene expression. A, shown is a schematic illustrating FOXO1-ΔDBD (Δ208–220) and FOXO1-CA + mut DBD (W209G/H215L). NES, nuclear export signal; NLS, nuclear localization signal. B–D, the −1800 rat Lhb-luc reporter was transfected into LβT2 cells along with 200 ng of pcDNA3 empty vector (EV), FOXO1, or FOXO1-CA (CA) as indicated. After overnight starvation in serum-free media, cells were treated for 6 h with 0.1% BSA vehicle (Veh) or 10 nm GnRH. The results represent the mean ± S.E. of at least three experiments performed in triplicate and are presented as basal transcription relative to empty vector (B and C) or -fold GnRH induction relative to the vehicle control (D). * indicates that Lhb-luc transcription is significantly repressed by FOXO1 or FOXO1-CA compared with empty vector using one-way ANOVA followed by Tukey's post-hoc test.