GENE-EXPRESSION OF EPIMORPHIN IN RAT INCISOR AMELOBLASTS

Epimorphin has been recently identified as an important factor in the morphogenesis of epithelial cells. A cDNA encoding epimorphin from ski n of newborn mice was cloned by the polymerase chain-reaction techniqu e before the preparation of digoxigenin-labelled cRNA probes. In situ hybridization of longitudinal sections of rat incisors revealed a dist inct pattern of expression of epimorphin mRNA in the ameloblast layer. Epimorphin mRNA was detected from the presecretory stage up to the be ginning of the maturation stage of amelogenesis. With the identificati on of this expression by epithelial-derived cells, i.e. ameloblasts, i t is thought likely that epimorphin is one of the factors that modulat e the differentiation cascade of ameloblasts in the course of amelogen esis.