Gastrulation - Adhesive Changes during PMC Ingression

Primary mesenchyme cells (PMCs) must undergo several changes in their adhesive properties in order to detach from the epithelium of the vegetal plate and ingress into the interior: (1) they must lose affinity for neighboring epithelial cells that remain in the vegetal plate; (2) they must lose affinity for the hyaline layer on the exterior of the embryo; and (3) they presumabl;y must gain affinity for the basal lamina,. since PMCs later migrate within the blastocoel. Hideki Katow anf Michael Solursh used transmission electron microscopy to show that PMCs undergo a dramatic reorganization of their cytoskeleton and their contacts with these three regions during ingression. A colorized adapatation of their original work is shown here: