Role of Runx Genes in Chondrocyte Differentiation

摘要: Runx2/Cbfa1 plays a central role in skeletal development as demonstrated by the absence of osteoblasts/bone mice with inactivated alleles. To further investigate Runx2 cartilage differentiation and to assess potential induce bone formation, we cloned chicken overexpressed it chick embryos using retroviral system. Infected wings showed multiple phenotypes consisting (1) joint fusions, (2) expansion carpal elements, (3) shortening elements. In contrast, formation was not affected. function during development, have generated transgenic that express dominant negative form cartilage. The selective inactivation chondrocytes results severe limbs due disturbance chondrocyte differentiation, vascular invasion, osteoclast periosteal formation. Analysis growth plates shows is positive regulator invasion. indicate promotes chondrogenesis either maintaining or initiating early differentiation. Furthermore, essential but sufficient osteoblast analyze runx genes performed situ hybridization Runx2- Runx3-specific probes. Both were coexpressed cartilaginous condensations, indicating cooperative regulation thus explaining expansion/maintenance carpus joints infected limbs.