FIG. 8.

HDAC4 and MEF2C cooperatively regulate c-jun promoter activity. (A) Schematic representation of the reporter pJLuc, which contains positions −225 to +150 of the c-jun promoter upstream of the luciferase coding sequence. (B) HDAC4 activates c-jun promoter activity in a MEF2C-independent manner. The pJLuc reporter and expression plasmids for HDAC4 or its mutants were cotransfected into NIH 3T3 cells. Luciferase (Luc) activities were normalized to the internal β-galactosidase control; the normalized luciferase activity from the transfection without any effector plasmid was arbitrarily set to 1.0. (C) HDAC4 represses MEF2C-dependent transcription. Together with the MEF2C expression plasmid, pJLuc and indicated HDAC4 plasmids were cotransfected into NIH 3T3 cells. Reporter assays were determined and calculated as for panel B. (D) Schematic representation of HDAC4 and its mutants used for panels B and C. Repression of MEF2C-dependent transcription by each construct is shown at the right.