Fig. 6. Ingression of the endodermal precursors. (A) Images from video recordings of the ingression of the E daughters, the endodermal precursors. The focal plane is through the center of the embryo. (a) 24-cell stage. The E daughters (nuclei indicated by single asterisks) are present on the surface of the embryo. (b) 28-cell stage. The E daughters have moved toward the interior of the embryo (top). (c) 46-cell stage. The E daughters have entered the body cavity and divided into the E granddaughters (double asterisks indicate the two visible granddaughters). Neighboring cells (triangle) cover the site of ingression. (d-f) Comparable stages of par-3(ZF1) embryos, labeled as above. Note that the E granddaughters remain on the surface of the embryo in f. (B) Confocal images of NMY-2^GFP in living embryos during the early stages of ingression, labels as above. The arrowheads in b,e indicate levels of NMY-2^GFP in the midbodies of dividing cells; arrows in c and f show the apical surfaces of the E daughters. Time points in minutes are indicated in the lower right-hand corner of each panel; t=0 was the 26-cell stage just after the MS(2) to MS(4) division. Scale bars: 5 µm.