Figure 5.

Overexpression of FoxL2 potentiates the effects of activin in LβT2 cells and confers activin responsiveness to the FSHβ gene in heterologous cells. A, LβT2 cells were transfected with a minimal heterologous thymidine kinase (TK) promoter (ctrl) or with four tandem copies (multimers) of the individual elements critical for activin responsiveness (indicated under each bar) linked to the TK promoter. The cells were treated with activin for 5 h and results presented as fold induction over vehicle control for each multimer. B, LβT2 cells were transfected with multimers consisting of four tandem repeats of the elements indicated below each group of bars, and contransfected with caALK7 or Smad3 or treated with activin for 5 h. *, Statistically significant induction of the multimer reporter compared with its control; #, significant difference in fold induction between two multimer reporters with the same treatment. C, LβT2 cells were transfected with the 1-kb mouse FSHβ reporter and treated with activin for 5 h. Normalized luciferase values are presented as fold induction from the vehicle-treated cells transfected with the empty vector control for FoxL2 overexpression. Data from empty vector control-transfected cells are represented by gray bars, whereas FoxL2-transfected cells are represented by black bars. *, Significant induction by activin; #, significant increase in fold induction by activin after transfection of FoxL2 by two-way ANOVA. D, CV-1 cells were transfected with empty vector control, caALK7, Smad3, or Smad3 and 4 with (black bars) or without FoxL2 (gray bars) expression vector. *, Significant induction by FoxL2; #, significant change in fold induction or synergy determined by two-way ANOVA after cotransfection of FoxL2 with caALK7, Smad3, or Smad3 and -4 (P < 0.05). ctrl, Control; unkn, unknown.