Figure 2. Laminin remodeling at the tip of the archenteron facilitates migration of the small micromeres to the posterior end of the coelomic pouch.
(A) Once the micromeres reach the tip of the gut, they undergo an epithelial–mesenchymal transition (EMT). By immunostaining, we see that laminin (red), at the time, is reduced as the small micromeres (SM, green) breach the top of the gut. (B) Once they reach the posterior coelomic pouch, laminin (red) surrounds the small micromeres (green) and NSM to encapsulate the coelomic pouch (yellow dashed circle). (C, D) Ectopically placed small micromeres underwent an EMT coincident with the endogenous EMT event of the skeletogenic cells. Laminin (red) is absent both at the site of skeletogenic cell ingression (indicated by white arrows at the site of ingression) and at the site of ectopic small micromere (SM, green) ingression (indicated by a yellow arrow).