Figure 2

Later internalizations resemble that of Ea/Ep. (A) Sequence of selected internalization events during gastrulation. Time represents developmental time from fertilization. Schematic representations obtained from imaging data. The area shaded in red during the ventral enclosure is shown in (E). (B) Internalization of AB cells in the head region (three-dimensional (3D) projection still images). Intensity-line plots (along the black dashed line in the left panel) for ABalppp were generated as for Figure 1B. (C) Dynamics during temporary covering of the lateral AB cell on the left side of the embryo (representations as in (B)); red arrows in the right panel indicated dynamic filopodia-like protrusion from the covering extensions. (D) Dynamics during mesoderm internalization. (Upper panel) Internalization of anterior mesoderm; white arrows indicate covering extensions and dashed line mark the leading edge. (Lower panel) Internalization of lateral mesoderm; right panels as in part (C). (E) Dynamics during ventral enclosure. Three cells that cover the ventral neuroblasts are labeled for better orientation. The purse-string cable in the covering cells is marked by a dashed red line, and its direction of movement by red arrows.