Figure 2.

In C2C12 cells, the activities of both GAL4–MEF2A and GAL4–MEF2C are enhanced by the over-expression of Smad2 and 4 with wild-type TGF-β receptors (TβR-I and -II), but not in the presence of a TGF-β dominant negative receptor, TβRII(K277R). (A–D) C2C12 cells were co-transfected with pCMV5B–TβRII(K277R), pCMV5B–TβR-I, pCMV5B–TβR-II, pCMV5B–Smad2, pCMV5B–Smad3, pCMV5B–Smad4, 5×GAL4-luc, GAL4(DBD), GAL4–MEF2A(91–507), GAL4–MEF2C(87–442) and pSV-βgal as indicated. Twenty-four hours after transfection, growth medium was replaced with 1% FBS ± 2 ng/ml of TGF-β. Cells were harvested 72 h after transfection for luciferase assays. β-galactosidase activities were used to normalise for transfection efficiency. Two or more sets of experiments were performed with comparable results. Each data point is the mean of triplicate samples from single experiments and the error bars represent the SEM.