Developmental expression of the tight junction protein, occludin, in the gastrointestinal tract of the chick embryo

Abstract

The developmental expression of occludin was studied biochemically in whole chick embryos to determine when intercellular tight junctions develop. Occludin mRNA was first detected after 3 days of incubation by the reverse transcriptase-polymerase chain reaction. On northern blot analysis, although occludin mRNA was not discernible in 3-day-old embryos, weak but clear expression was noted on day 4 of incubation and increased dramatically in 5-day-old embryos. Occludin was not detectable on days 3 or 4 of incubation by western blot analysis, and was first detected in 5-day-old embryos. In addition, the expression of occludin was examined immunohistochemically in the gastrointestinal tract of 3- to 21-day-old embryos. Immunoreactivity for occludin was not expressed on day 3 of incubation. On day 4 of incubation, weak immunoreactivity was demonstrated in the gastrointestinal tract, and gradually became stronger with development. By day 11 of incubation, a positive immunoreaction was obtained only on the apical surfaces of the epithelial cells, i.e., at the junctional complexes, while weak immunoreactivity was diffusely distributed throughout the epithelial cells. The possible roles of occludin in the developing gastrointestinal tract are discussed.

Mosaic analysis of small intestinal development using the spf ash -heterozygous female mouse

“…In development of the mouse small intestine, expression of several basal laminar components and intercellular adhesion molecules changes (Simon-Assmann et al 1990Kawasaki et al 1998;Lefebvre et al 1999;Angres et al 2001), and this may be related to the patch size and patch shape changes. It will also be intriguing to study cell-cell adhesion of epithelial cells in intestinal development in the future.…”

Histochemistry and cell biology: what's in a name?

“…The tight junction component occludin expression was investigated in the gastrointestinal tract of 3-to 21-day-old chick embryos by RT-PCR and immunohistochemistry (Kawasaki et al 1998). Two types of polysialic acid, one present on megalin and the other on the neural cell adhesion molecule, showed mutually exclusive expression during kidney development and maturation (Ziak and Roth 1999).…”