MICROSCOPY Vol.44▶No.4 2009

Heterogeneity of fusion phenomena in maxillo-facial morphogenesis and epithelial cell differentiation during the fusion of palatal shelves

Toshiya Takigawa

Abstract: Although so-called ‘fusion’ morphologically divides into two different types, ‘ostensible fusion’ and ‘actual fusion’, very little is known about the heterogeneity of fusion in maxillo-facial morphogenesis. Moreover, the controversy concerning the mechanism of epithelial disappearance continues even to the fusion of palatal shelves, which has been most often researched as a model of ‘actual fusion’.
In this paper, I explained the morphological difference between ‘ostensible fusion’ and ‘actual fusion’ in so-called ‘fusion’. In addition, I showed a case of epithelial disappearance by means of cell migration, epithelial –mesenchymal transformation, and apoptosis, in a single palatal shelf culture method of fetal mice. Such cell differentiation suggests how epithelial cells disappear during ‘actual fusion’.

Key words: fusion, palatal medial edge epithelial cells, terminal differentiation, organ culture