“…Proteins of numerous molecular families have been implicated in the longitudinal growth of the skeleton including growth factors, e.g., bone morphogenetic proteins, fibroblast growth factor family members, insulin-like growth factor signaling components (Cancedda et al, 1995); extracellular matrix molecules, e.g., collagen II, aggrecan, link protein and cartilage oligomeric protein (Cheah et al, 1991;Watanabe et al, 1994;Fang et al, 2000;Tuckermann et al, 2000); and transcription factors, e.g., Sox9, Core-binding factor alpha (Cbfa1) and ATF-2. In particular, Sox9 has been shown to be required for chondrogenesis, ATF-2 controls cell cycle progression and proliferation, and Cbfa1/Runx2 is involved in hypertrophic differentiation (Reimold et al, 1996;Lefebvre and de Crombrugghe, 1998;Beier et al, 1999;Bi et al, 1999;Stricker et al, 2002).…”