Regulation of osteoblast differentiation by transcription factors

Runx2, osterix, and beta-catenin are essential for osteoblast differentiation. Runx2 directs multipotent mesenchymal cellstoan osteoblastic lineage, and inhibitsthem from differentiating into the adipocytic and chondrocytic lineages. After differentiating to preosteoblasts, beta-catenin, osterix, and Runx2 directthem to immature osteoblasts, which produce bone matrix proteins, blocking their potential to differentiate into the chondrocytic lineage. Runx2 inhibits osteoblast maturation and the transition into osteocytes, keeping osteoblasts in an immature stage. Other transcription factors including Msxl, Msx2, Dlx5, Dlx6, Twist, AP1 (Fos/Jun), Knox-20, Sp3, and ATF4 are also involved in osteoblast differentiation. To gain an understanding of bone development, it is importantto position these transcription factors to the right places in the processes of osteoblast differentiation.