Cloning and characterization of the mouse and human enamelin genes

Enamelin is likely to be essential for proper dental enamel formation. It i s secreted by ameloblasts throughout the secretory stage and can readily be isolated from the enamel matrix of developing teeth. The gene encoding hum an enamelin is located on the long arm of chromosome 4, in a region previou sly linked to an autosomal-dominant form of amelogenesis imperfecta (AI). T o gain information on the structure of the enamelin gene and to facilitate the future assessment of the role of enamelin in normal and diseased enamel fori-nation, we have cloned and characterized the mouse and human enamelin genes. Both genes are about 25 kilobases long. The enamelin gene has 10 ex ons interrupted by 9 introns. Translation initiates in exon 3 and terminate s in exon 10. All of the intron/exon junctions within the mouse and human e namelin coding regions are between codons, so there are no partial codons i n any exon, and deletion of one or more coding exons by alternative RNA spl icing would not shift the downstream reading frame.