8 research outputs found
Smad7 regulates terminal maturation of chondrocytes in the growth plate
Members of the bone morphogenetic protein (BMP) superfamily, including transforming growth factor-betas (TGFβ), regulate multiple aspects of chondrogenesis. Smad7 is an intracellular inhibitor of BMP and TGFβ signaling. Studies in which Smad7 was overexpressed in chondrocytes demonstrated that Smad7 can impact chondrogenesis by inhibiting BMP signaling. However, whether Smad7 is actually required for endochondral ossification in vivo is unclear. Moreover, whether Smad7 regulates TGFβ in addition to BMP signaling in developing cartilage is unknown. In this study, we found that Smad7 is required for both axial and appendicular skeletal development. Loss of Smad7 led to impairment of the cell cycle in chondrocytes and to defects in terminal maturation. This phenotype was attributed to upregulation of both BMP and TGFβ signaling in Smad7 mutant growth plates. Moreover, Smad7−/− mice develop hypocellular cores in the medial growth plates, associated with elevated HIF1α levels, cell death, and intracellular retention of types II and X collagen. Thus, Smad7 may be required to mediate cell stress responses in the growth plate during development
Cloning of the human and mouse type X collagen genes and mapping of the mouse type X collagen gene to chromosome 10
Identification of a promoter element within the zebrafish Collagen X¿1 gene responsive to Runx2 isoforms Osf2/Cbfa1 and til-1 but not to pebp2aA2
Type X collagen is a short chain collagen
specifically expressed by hypertrophic chondrocytes
during endochondral ossification. We report here the
functional analysis of the zebrafish (Danio rerio) collagen
Xa1 gene (colXa1) promoter with the identification
of a region responsive to two isoforms of the runt domain
transcription factor runx2