Expression of core binding factor Osf2/Cbfa-1 and bone sialoprotein in tooth development

The transcription factor Osf2/Cbfa1 is a key regulator of osteogenic differentiation while BSP, a major non-collagenous protein, is a marker of osteoblastic differentiation. To determine the relationship between Osf2/Cbfa1 and the formation of mineralized tissues in tooth development we have studied the temporal expression of Osf2/Cbfa1 and BSP mRNA using in situ hybridization. These studies show that Osf2/Cbfa1 is expressed early in mesenchymal and epithelial tissues destined to form the mineralized tissues of the tooth and periodontal tissues, whereas BSP provides a specific marker for the differentiated cells in each of these tissues. Expression of Osf2/Cbfa1, but not BSP, was observed in the periodontal ligament indicating that expression of Osf2/Cbfa1 is not restricted to mineralizing tissues.