Cell adhesion properties of neural stem cells in the chick embryo.

The nervous system of vertebrates is derived from an early embryonic region referred to as the neural plate. In the chick embryo, the neural plate is populated by neural stem cells specified from the epiblast shortly after the onset of gastrulation. Accompanying the formation of the plate, chondroitin sulfate glycosaminoglycans are expressed in the basal extracellular matrix. We describe in vitro experiments measuring cell adhesion of epiblast cells during the formation of the neural plate. Our findings may suggest that neural stem cells are set apart from non-neural epiblast by changes in relative cell-cell and cell-substrate adhesion. Specifically, changes in cell adhesion separating neural stem cells from the non-neural epiblast may be augmented by the presence of exogenous chondroitin-6-sulfate in the epiblast basal lamina at the time neural progenitors are specified in the epiblast.