The morphology of the migrating epiblast edge in gastrulating quail embryos: An SEM study of the effects of tissue handling before fixation on the attachment side

Publisher Website
Google Scholar
Abstract
The expansion of the quail extraembryonic epiblast is a useful system for the study of epithelial sheet locomotion. A band of cells at the epiblast edge, referred to as edge cells (EC), adheres to the vitelline membrane. The attachment side of the EC and the dorsal surface of the submarginal cells were examined with scanning electron microscopy (SEM) after different fixation procedures. Our results indicate that especially the number of the submarginal microvilli and the surface structures of the lamellipodia are affected by tissue handling before fixation. The attachment region consists of overlapping lamellipodia that are bordered by filopodia. Proximal edge cells have a smooth contour, and they are probably elongated and oriented perpendicularly to the direction of locomotion of the EC. Parts of the proximal edge are occupied by lamellipodia and threadlike extensions. The submarginal cells located nearest the EC are usually outlined by intercellular ridges and numerous blebs, whereas the more central cells are outlined by microvilli.