Amelotin (AMTN)

The mineralized portions of teeth, the dentin and enamel, are formed by mesenchyme-derived odontoblasts and epithelium-derived ameloblasts, respectively. As ameloblasts differentiate, they deposit specific proteins necessary for enamel formation, including amelogenin (AMELX), enamelin (ENAM), and ameloblastin (AMBN), in the organic enamel matrix. Amelotin is specifically expressed in maturation-stage ameloblasts.The mouse and human proteins both contain N-terminal signal sequences and are rich in proline, leucine, and threonine. Amtn was expressed exclusively in teeth.In situ hybridization analysis revealed that Amtn was expressed only in maturation-stage ameloblasts during mouse tooth development.Amtn protein was efficiently secreted from transfected cells in culture.