Fig. 6. Slam localizes to the furrow canals during cellularization. Embryos are stained in green with -Neurotactin, which marks surfaces of membrane during cellularization. -Slam is in red; overlap is yellow. (A-D) Slam localizes to the basal-lateral domain of the invaginating plasma membrane from early cellularization (A) to the end of cellularization (D). Note the decrease of Slam expression in the ventral part of the embryo at the end of cellularization (D). (E,F) Posterior pole during early (E) and late (F) cellularization. Slam is not expressed in the germ cells. (G) Enlarged double-labeling of Slam and Neurotactin reveals Slam (red) preceding Neurotactin (green) in growing membrane during early cellularization. (H) Section (2 µm) through gastrulating embryo. White arrow indicates lack of Slam in the farthest invaginated cells. Black arrow indicates presence of Slam in the basal membrane of cells that will become adjacent to migrating germ cells at stage 10-11. White arrowhead indicates germ cells.