FIGURE 8.

Apical constriction of anterior cells. (A) Maximum intensity projections of stacks of confocal images from time lapse recordings of a representative wt embryo expressing a membrane-localized GFP under the control of the pha-4 promotor imaged from the ventral side. The individual compartments of the alimentary system are highlighted in the right panel. See also Supplementary Video 13. (B) Top: Maximum intensity projections of stacks of confocal images from time lapse recordings of representative wt embryo imaged from the ventral side. White lines mark the outlines of the embryo. Bottom: Central confocal plane from time lapse recordings of a representative wt embryo imaged from the left side. Green arrowheads mark the anterior cell surfaces that acquire and accumulate NMY-2. The dashed white line highlights cells that have undergone apical constriction. The solid white line traces a cell that undergoes apical constriction and thereby moves juxta-orally. See also Supplementary Video 10. (C) Maximum intensity projections of stacks of confocal images from time lapse recordings of a representative wt embryo imaged from the left side. Labial sensilla (green) and the left amphid sensillum (magenta) are tracked. (D) Schematic illustrating how sequential, collective apical constriction at the anterior tip of the embryo creates the anterior-most epithelial part of the mouth (arcade cells, light green) and, simultaneously, invagination of anteriorly localized neurons.