A novel approach to the growth analysis of hamster secondary palate by histone 3 m RNA in situ hybridiration

Abstract

A study was undertaken to determine the cell proliferation kinetics during the development of hamster vertical palatal shelf ad initium. Harnster embryo heads, obtained at different times between days 10 and 12 of gestation (which is the period of vertical shelf development) were processed and sectioned to localize histone 3 mRNA, a cell cycle specific gene, by in situ hybridization. Sense and antisense 35~-labelledh istone 3 riboprobes were used as hybridization probes. Percent labelled cells were determined. The results showed that a high rate of random proliferation of both epithelial and mesenchymal cells was a major component of early vertical palatal growth. Subsequently, during the latter half of vertical shelf development, the proliferation rates of the epithelial and mesenchymal cells were different in a region specific manner. It was suggested that the spatio-temporal changes in the distribution of cycling mesenchymal and epithelial cells during vertical palate development may indicate their heterogeneity for subsequent segregation into appropnate phenotypes.