MYOGENIN BINDS TO AND REPRESSES C-FOS PROMOTER

Myogenin (a member of the myogenic basic helix-loop-helix transcriptio n factor family) seems to be the main effector of proliferation repres sion, a crucial step which precedes muscle cell terminal differentiati on during muscle development. Proliferation repression most likely occ urs through inhibition of proliferation-associated genes such as the p roto-oncogene, c-fos. Here, we demonstrate that myogenin binds to an E -box located in the main element of the c-fos promoter, the serum resp onse element (SRE). Results from co-transfection experiments indicate that myogenin acts as a repressor for the SRE. Our data suggest that m yogenin could play a role in c-fos inhibition at the onset of muscle c ell terminal differentiation.