[CBFA1/PEBP2 alpha A].

A transcription factor, Cbfa1/Pebp2 alpha A, which belongs to runt-domain gene family, is preferentially expressed in the osteoblast lineage. Cbfa1/Pebp2 alpha A-deficient mice lacked both intramembranous and endochondral ossification completely. The differentiation of osteoblast was blocked, and the maturational disturbance of osteoclasts was also observed in the mutant mice. Further, the Cbfa1/Pebp2 alpha A expression in nonosteoblastic cells induced osteoblastic markers in vitro. These data demonstrate that Cbfa1 is an essential transcription factor for osteoblast differentiation and bone formation. Heterozygously mutated mice in the Cbfa1/Pebp2 alpha A locus showed the similar phenotype with cleidocranial dysplasia, which is an autosomal inherited disease. And the mutations of CBFA1/PEBP2 alpha A locus were identified in the patients with cleidocranial dysplasia.