FIGURE 2.

MEF2A mediates SENP2 activity on the myostatin promoter. A, schematic of the various deletion fragments generated to identify the minimal promoter region required for myostatin activity. There is one MEF2 binding site (MBS) in pMSTN4 but not in pMSTN3. C2C12 cells were transfected with various deletion fragments and SENP2, and luciferase activity was measured 24 h after transfection. The data are presented as mean ± S.D. of three independent experiments. B, C2C12 cells were transfected with FLAG-tagged SENP2 or SENP2m plasmid, and relative luciferase activity was measured 24 h after transfection. The data are presented as mean ± S.D. of three independent experiments. Differences between SENP2 and SENP2m or control cells were significant (p < 0.05, Student's t test). C, C2C12 cells were transfected with pMSTN4 or pMSTN4m plasmid, and relative luciferase activity was measured 24 h after transfection. The data are presented as mean ± S.D. of three independent experiments. Differences between SENP2 and SENP2m or control cells were significant (p < 0.05, Student's t test). D, C2C12 cells were transfected with MEF2A, MEF2B, MEF2C, or MEF2D plasmid, and luciferase activity was measured 24 h after transfection. The data are presented as mean ± S.D. of three independent experiments. Differences between MEF2A and MEF2B, MEF2C, MEF2D, or the control were significant (p < 0.05, Student's t test). E, C2C12 cells were transfected with NS-siRNA (si-NS), MEF2A siRNA (si-MEF2A), MEF2B siRNA (si-MEF2B), MEF2C siRNA (si-MEF2C), or MEF2D siRNA (si-MEF2D), and the expression of MEF2 proteins was analyzed by Western blot analysis (right panel). Luciferase activity was measured 24 h after transfection. The data are presented as mean ± S.D. of three independent experiments.