A Western blot analysis and immunohistochemical study of 4-day old mice teeth over-expressing amelotin during amelogenesis

Amelotin is an enamel-specific gene product, and its expression under normal circumstances is limited to maturation-stage (or late-stage) amelogenesis. The altered pattern of amelotin gene expression is achieved by creating transgenic animals in which the amelogenin gene promoter is used to drive amelotin. This study sets out to analyze transgenic animals in which amelotin is expressed throughout all stages of enamel formation (amelogenesis). This thesis will include an introduction and background in tooth development (including amelogenesis), and present results demonstrating animal genotype confirmation, transgene expression profiles by immunohistochemical and Western analysis and enamel phenotype using electron microscopy. We hypothesized that "The transgene will be functional, and that the amelotin transgene will be expressed throughout all stages of amelogenesis, resulting in an abnormal enamel structure." Data from immunohistochemical studies showed amelotin to be expressed throughout all stages of amelogenesis, with relatively higher expression in the maturation stage of amelogenesis. Western blot analysis confirmed the over-expression of amelotin in these animals. Transgene expression was confirmed during all stages of amelogenesis, and scanning electron microscopy (SEM) imaging showed that the transgenic animals had a highly disrupted enamel structure. The conclusions were that transgenic mice over-expressing amelotin during amelogenesis result in a disrupted enamel architecture, and future studies are aimed at defining whether enamel hypomineralization and hypoplasia are also a feature of these teeth.