Transcription Regulation of by the Triple Complex of Mef2c, Creb1 and Myod.

has been identified as a direct, downstream target gene of MRF in the skeletal muscle. The overexpression of represses myogenic proliferation and promotes cell differentiation. Previous studies have defined the 0.7 kb upstream fragment of the gene. In the present study, we have further determined two clusters of transcription factor-binding motifs in the 0.7 kb promoter: CRE#2-E#1-CRE#1 in the proximal region and Mef2#3-CRE#3-E#4 in the distal region. Utilizing transcription assays, we have also shown that the reporter containing the Mef2#3-CRE#3-E#4 motifs is synergistically transactivated by Mef2c and Creb1. Further studies have mapped out the protein-protein interaction between Mef2c and Creb1. In summary, our present studies support the notion that the triple complex of Mef2c, Creb1 and Myod interacts with the Mef2#3-CRE#3-E#4 motifs in the distal region of the promoter, thereby driving expression during skeletal muscle development and regeneration.