Dorsal alignment of the valve and intestine.

<p>(A) Horizontal optical plane near the center of an embryo shortly after the birth of v3D; the top panel shows the E16 primordium and the bottom panel is the same plane showing all cell membranes. Note that v3D is deeply embedded between the left and right anterior intestinal cells (int1^p cells). (B) Expression of PAR-6 and HMR-1/E-cadherin at the double plate stage (see <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003772#pgen.1003772.s002" target="_blank">Figure S2</a> for developmental sequence). Closed arrowheads indicate contacts between intestinal cells and v3D, and open arrowheads indicate contacts between intestinal cells and other cyst cells. (C) High magnification through a plane as in panel A, but taken at the late double plate stage. A shallow cleft (arrow) occupied by a process from v3D remains at the left-right boundary between the int1^p intestinal cells. (D) Transverse plane showing the wedge-shape of the v3D cell body between the left and right int1^p cells. (E) Transverse plane just anterior to the plane shown in panel D, showing the cuboidal shapes of other double plate cells. (F) Time-lapse sequence to 350 minutes showing the intercalation of v3D dorsally across the int1^p cells. The arrow indicates a lamellipodium that leads v3D intercalation. The bold black line indicates the dorsal margin of the double plate. (G) v3D in a <i>die-1(w34)</i> embryo at 350 minutes. (H) v3D in a <i>egl-43(zu471)</i> embryo at 350 minutes; v3D has partially engulfed a cell death. Bars: (A–H) 5 microns.