Identification and Functional Characterization of Distinct Critically Important Bone Morphogenetic Protein-specific Response Elements in the Id1 Promoter

Transforming growth factor-beta (TGF-beta) family members, which include bone morphogenetic proteins (BMPs) and TGF-betas, elicit their cellular effects by activating specific Smad proteins, which control the transcription of target genes. BMPs and TGF-betas have overlapping as well as specific effects on mesenchymal cell differentiation for which the mechanisms are incompletely understood. Here we report that Id1, a dominant negative inhibitor of basic helix-loop-helix proteins, is a direct target gene for BMP. BMP, but not TGF-beta, strongly activates the Id1 promoter in an Smad-dependent manner. We identified two BMP-responsive regions in the mouse Id1 promoter, which contain three distinct sequence…