3-D Movies of Zebrafish Gastrulation:
Hypoblast formation in lateral germ ring.
Turning inward of cells to form the hypoblast, convergence of cells toward the dorsal side.
Hypoblast formation movie: The animal pole is toward the top, dorsal is toward the right.
Scatter labeling of cells with the flourescent probe, Bodipy-dextran, allows many individual cells to be followed through time. Notice cells on the surface are generally moving vegetally (toward the bottom of image). Cells that are at or close to the margin move from the surface layer into the hypoblast (inner layer of cells). Once in the hypoblast, cells move away from the margin toward the animal pole (top of image). This movement of cells creates the germ layers of the embryo. Remember, not all of the cells are labeled in the embryo; the holes that you see between the cells are filled with cells that are not labeled with the flourescent probe.