Tooth morphogenesis and cell differentiation.

The tooth is one of the vertebrate organs in which development at the molecular level is beginning to be understood. Secreted signaling molecules have been identified that mediate sequential and reciprocal inductive interactions between the dental epithelium and mesenchyme. Transcription factors have been found that participate in these signaling cascades. A signaling or organizing center was recently discovered in the dental enamel knot that expresses the same signals as other organizing centers in the embryo, and which presumably regulates tooth shape. It has recently become evident that the signaling networks that operate in the development of mammalian teeth are similar to those that are involved in the development of other vertebrate organs.