Fig. 12

Behavior of posterior blastopore lip cells undergoing convergence and extension (3c², 3d²). a–aa Projected confocal Z slices of embryos injected with dextran or diI, into 3c, 3d or their subclones, as indicated. a Ventral view of an embryo at epiboly stage. b–u Frames from a time-lapse of the same embryo as shown in a. b–l Frames from a time-lapse movie of the same embryo undergoing convergence and extension to zipper the posterior blastopore (bp) closed. m–r Frames from the same movie showing membrane protrusions (arrows) and cilia (arrow heads) on the cells undergoing convergent extension (zippering). s, t Frames from the same movie showing that the cells undergoing convergence and extension are from the 3c² and 3d² cells. The asterisk (*) marks cells from the 3c¹ and 3d¹ clones that migrate anteriorly towards the ventral side of the stomodeum. In u, the 3c²¹¹ and 3d²¹¹ cells have entered the deeper parts of the mouth and are out of view of the stack, indicated by dashed lines. v–aa Live confocal images of post-zippering-stage embryos showing the movement of the 3c²²¹ and 3d²²¹ cells posteriorly, between cells of the 2d clone. bb–mm Images of fixed embryos stained for acetylated tubulin (to mark cilia) and DAPI (to mark DNA). bb, cc Shows ventral views (vv) of embryos at the early stages of convergent extension and arrowheads point to cilia on cells at the posterior edge of the blastopore. dd–ff Ventral views of embryos during elongation. The ciliated left and right terminal cells (ltc, rtc) are labeled. gg Posterior view (pv) of the same embryo shown in ff. Scale bar in l and mm are equal to 50 μm; scale bar in v equals 20 μm. See also Additional files 9 and 10