Fig. 7.

Disruption of GR binding to DNA significantly reduces the ability of activin and glucocorticoids to synergistically activate FSHβ gene expression. A, The −1000FSHβluc reporter gene with TKβgal was transiently transfected into LβT2 cells along with either 200 ng wild-type GR and normalized to the vehicle control transfected with wild-type GR (WT, black bars) or with mutant GR, either GRdim4 (dotted bars) or GR DBDmut (striped bars) and normalized to the vehicle control transfected with the corresponding mutant GR. After overnight starvation in serum-free media, the cells were treated for 24 h with 10 ng/ml activin and/or with 100 nm dexamethasone (Dex) as indicated. #, Induction by the mutant GR is significantly different from induction with wild-type GR by one-way ANOVA followed by Tukey's post hoc test. B and C, The wild-type −1000FSHβluc reporter gene or one of three cis-mutated reporters, GR, and TKβgal were transiently transfected into LβT2 cells. After overnight starvation in serum-free media, the cells were treated for 24 h with either vehicle (white bars) or 100 nm dexamethasone (Dex, black bars) (B) or 10 ng/ml activin (Act) plus 100 nm dexamethasone (Dex, black bars) (C). *, Hormone treatment significantly different from the vehicle-treated control of the same reporter gene by Student's t test; #, induction of the mutant reporter gene is significantly different from the induction of the wild-type reporter gene, using one-way ANOVA followed by Tukey's post hoc test.