Molecular cloning and DNA sequence of rat amelogenin and a comparative analysis of mammalian amelogenin protein sequence divergence.

The developing rat incisor is a common model used in the study of enamel development. It has been impossible to study correlation between rat enamel structure and the sequence of the major developing enamel protein in this species as to date a DNA sequence for rat amelogenin has not been reported. This study presents the first cloning of a full-length cDNA copy of rat amelogenin and its deduced primary sequence. Detailed analysis of this sequence provides evidence that the gene has evolved by internal sequence duplication. Comparison of the rat amelogenin primary sequence with those published for other species provides evidence that this protein, while exhibiting extreme levels of sequence conservation, has been subject to significant structural changes that may be related to alterations in enamel structure in different mammalian groups.