Temporal and Spatial Expressions of FGF18 in the Developing Tooth

objectives: To investigate the effects of FGF18 on tooth development. Materials and Methods: The complete encoded sequence mouse FGF18 gene was amplified by nested RT-PCR from mouse tooth germ, cloned into PGEM-T vector and identified by means of PCR test and KpnI/HindIII digestion, then the cloned cDNA in this recombinant plasmid was sequenced. The open reading frame of FGF18 cDNA was inserted into prokaryotic expression vector pRSET-B to made FGF18 polyclonal antibody. Finally we studied the expressions of FGF18 in tooth development by immunohistochemistry method. Paraffin sections of mouse developing tooth germ were used. Results: FGF18 was expressed in dental epithelium and enamel organ (bud stage). No Positive expressions were found (cap stage). FGF18 was found in both inner/outer enamel epithelial cell and dental sac cells, and weak positive expressions were in dental papilla cells, but no expressions were found in stratum intermedium and stellate reticulum cells. Positive expressions were found in osteoblast and chondrocyte too (early bell stage). Strong positive expressions were found in ameloblast and odontoblast (late bell stage). Conclusions: FGF18 have effects on cell differentiation and matrix mineralization as well as tooth initiation