Conserved regulatory motifs in osteogenic gene promoters integrate cooperative effects of canonical Wnt and BMP pathways

• Published in: Journal of bone and mineral research 2011-04, Vol.26 (4), p.718-729
• Main Authors: Rodríguez‐Carballo, Edgardo, Ulsamer, Arnau, Susperregui, Antonio RG, Manzanares‐Céspedes, Cristina, Sánchez‐García, Eva, Bartrons, Ramon, Rosa, José Luis, Ventura, Francesc
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors - genetics; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors - metabolism; beta Catenin - genetics; beta Catenin - metabolism; Biological and medical sciences; BMP; Bone Morphogenetic Protein 2 - pharmacology; Bone Morphogenetic Proteins - pharmacology; Cell Differentiation - physiology; Cell Line; Conserved Sequence - physiology; Core Binding Factor Alpha 1 Subunit - genetics; Core Binding Factor Alpha 1 Subunit - metabolism; DLX5; DNA - metabolism; Enhancer Elements, Genetic - physiology; Fundamental and applied biological sciences. Psychology; Gene Expression - drug effects; Gene Expression - genetics; Gene Expression Regulation - physiology; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Mesenchymal Stromal Cells - cytology; Mesenchymal Stromal Cells - drug effects; Mesenchymal Stromal Cells - metabolism; Mice; Mice, Inbred Strains; MSX2; Mutation - physiology; OSTEOBLAST DIFFERENTIATION; Osteoblasts - cytology; Osteoblasts - metabolism; Osteogenesis - genetics; OSTERIX; Promoter Regions, Genetic - physiology; Protein Binding - physiology; Protein Interaction Domains and Motifs - physiology; RUNX2; Signal Transduction - physiology; Skeleton and joints; Skull - drug effects; Skull - metabolism; Smad Proteins - genetics; Smad Proteins - metabolism; Sp7 Transcription Factor; TCF Transcription Factors - genetics; TCF Transcription Factors - metabolism; Transcription Factor 4; Transcription Factors - genetics; Transcription Factors - metabolism; Vertebrates: osteoarticular system, musculoskeletal system; WNT; Wnt Proteins - pharmacology; Wnt3 Protein
• ISSN: 0884-0431; 1523-4681
• DOI: 10.1002/jbmr.260

Osteoblast differentiation depends on the coordinated network of evolutionary conserved transcription factors during bone formation and homeostasis. Evidence indicates that bone morphogenetic protein (BMP) and Wnt proteins regulate several steps of skeletal development. Here, we provide a molecular description of the cooperative effects of BMP and Wnt canonical pathway on the expression of the early osteogenic genes Dlx5, Msx2, and Runx2 in C2C12 cells, primary cultures of bone marrow–mesenchymal stem cells, and organotypic calvarial cultures. Coordinated regulation of these genes leads to the cooperative activation of their downstream osteogenic target gene osterix. Induction of these genes is mediated through enhancer regions with an evolutionary conserved structure encompassing both Smad and TCF/LEF1 DNA‐binding sites. Formation of a cooperative complex is mediated through DNA binding of Smads and TCF4/β‐catenin to their cognate sequences, as well as protein‐protein interactions between them. The formation of these cooperative transcriptional complexes results in a more efficient recruitment of coactivators such as p300. We propose that evolutionary conserved regulatory regions in specific osteogenic master genes are key integrative modules during osteogenesis. © 2011 American Society for Bone and Mineral Research.