Runx2 and dental development.

The Runx2 gene is a master transcription factor of bone and plays a role in all stages of bone formation. It is essential for the initial commitment of mesenchymal cells to the osteoblastic lineage and also controls the proliferation, differentiation, and maintenance of these cells. Control is complex, with involvement of a multitude of factors, thereby regulating the expression and activity of this gene both temporally and spatially. The use of multiple promoters and alternative splicing of exons further extends its diversity of actions. RUNX2 is also essential for the later stages of tooth formation, is intimately involved in the development of calcified tooth tissue, and exerts an influence on proliferation of the dental lamina. Furthermore, RUNX2 regulates the alveolar remodelling process essential for tooth eruption and may play a role in the maintenance of the periodontal ligament. In this article, the structure of Runx2 is described. The control and function of the gene and its product are discussed, with special reference to developing tooth tissues, in an attempt to elucidate the role of this gene in the development of the teeth and supporting structures.