Fig. 6.

Smad Proteins Are Necessary and Sufficient for LHβ Induction by Activin

A, Cells transfected with wild-type LHβ-luc were treated for 6 h with vehicle (white bars) or 10 ng/ml activin (black bars). Cells were cotransfected with an expression vector for Smad7 or its empty vector control, to assess the necessity for Smad protein activation in the induction by activin. Results represent the means of three independent experiments each performed in triplicate. *, Statistically significant difference from the control cells transfected with the wild-type vector. B, Cells transfected with wild-type LHβ-luc, or each SBE mutation introduced into LHβ-luc, were cotransfected with Smad3 or empty vector control (control). Activin was added to the cells 24 hr after transfection (filled bars are activin treated and white bars are control) and after6hof treatment, luciferase activity was measured and normalized to β-galactosidase. Results represent the means of three independent experiments each performed in triplicate. *, Statistically significant induction by activin; #, statistically significant induction by Smad3 overexpression as analyzed by ANOVA and Tukey’s post hoc test. WT, Wild type.