Basic fibroblast growth factor (FGF-2) in mouse tooth morphogenesis.

This study describes the spatio-temporal expression of basic Fibroblast growth factor (FGF-2) during odontogenesis of mouse as revealed by immunohistology. Parasagittal sections of mouse embryo head (13-18 day of gestation) containing various stages of developing tooth were incubated with a polyclonal anti-FGF-2 antibody and positive binding was evidentiated by using Streptavidin-Biotin complex-HRP system and AEC staining. We observed no FGF-2 staining at the dental lamina stage. At the bud stage slight staining is seen, limited to some epithelial cells. The intensity of the staining increases at the cap stage. In the bell stage, the stellate reticulum cells stain intensely. Later, odontoblasts and the dentin matrix stain deeply; but the epithelial cells stain faint. The extra cellular matrix of the dentin and dental papilla stain very intense but the enamel matrix is found negative. These results indicate the participation of FGF-2 in differentiation rather than in proliferation of tooth-forming cells. In particular, it appears that FGF-2 participates in odontoblast differentiation and in dentin matrix deposition. The spatio-temporally specific distribution pattern of FGF-2 in developing mouse tooth reported here emphasizes the importance of FGF-2 in mammalian odontogenesis.

Cellular and molecular regulation of odontogenesis.

Developing mammalian tooth is one of the most interesting model systems to study the mechanism of morphogenetic process especially to understand problems associated with spatial organization and symmetry. In the present article we recapitulate the morphologic aspects of odontogenesis and discuss the cellular and molecular regulatory factors involved in this process. The importance of cellular aspects such as epithelial-mesenchymal interactions and the cell kinetics are described. Role of growth factors such as Transferrin, Epidermal Growth Factor and its receptor and Transforming Growth Factor is analyzed. In addition the studies on transcription factors such as c-fos and Egr-1 and on homeobox genes are discussed to understand the molecular mechanism of odontogenesis.