<prompt> The gene that defines the localization of the tooth germs is:Fgf-8Bmp-2Dlx-5Pax-9  <response>: During tooth development, several mesenchymal molecules and their receptors act as mediators of epithelial-mesenchymal interactions. Bone morphogenetic proteins BMPs 2,4,7 mRNAs shift between epithelium and mesenchyme during regulation of tooth morphogenesis. Fibroblast growth factor FGF8 FGF9 have been localized in the dental mesenchyme and act via downstream factors MSX1 and PAX9. Muscle specific homeobox genes MSX-1 and MSX-2, appear to be involved in epithelial-mesenchymal interactions and craniofacial development, particularly in the initiation of developmental position MSX-1 and further development of MSX-2 of tooth buds. Pax-9 is transcription factor necessary for the development of MSX 2 of tooth buds. Pax 9 is a transcription factor necessary for tooth morphology. 