Role of cbfal in osteoblast and chondrocyte differentiation

摘要

Cbfal is a transcription factor, which belongs to the runt-domain gene family. Cbfal is expressed in osteoblasts and chondrocytes, and its expression is increased according to their maturation. Cbfal has two isotypes with different N-terminal domains, and the two isotypes show different activities in the regulation of their target genes. Cbfal-deficient mice showed a complete lack of bone formation in the absence of mature osteoblasts, and forced expression of Cbfal in mesenchymal cells induced osteoblastic markers, indicating that Cbfal is an essential factor for osteoblast differentiation. Chondrocyte maturation and osteoclast differentiation was also blocked in mutant mice. RANKL was barely detectable in Cbfal-deficient mice, suggesting that Cbfal induces osteoclast differentiation by the regulation of RANKL in osteoblastic cells. These data demonstrate that Cbfal plays an essential role in bone formation.