Osteocalcin gene promoter: Unlocking the secrets for regulation of osteoblast growth and differentiation

The bone tissue-specific osteocalcin gene remains one of a few genes that e xhibits osteoblast-restricted expression. Over the last decade, characteriz ation of the promoter regulatory elements and complexes of factors that con trol suppression of the osteocalcin gene in osteoprogenitor cells and trans activation in mature osteoblasts has revealed transcriptional regulatory me chanisms that mediate development of the osteoblast phenotype. In this revi ew, we have focused on emerging concepts related to molecular mechanisms su pporting osteoblast growth and differenliation based on the discoveries tha t the osteocalcin gene is regulated by homeodomain factors, AP-1 related pr oteins, and the bone restricted Cbfa1/AML3 transcription factor. I. Cell. B iochem. Suppls. 30/31.62-72, 1998. (C) 1998 Wiley-Liss, Inc.