Fig. 2. Phenotype of ceh-16(lg16) mutants and mosaic animals. (A,C,E,G,I,K) Fluorescence micrographs of living animals [1.5-fold stage, except for E,F (bean stage) and K,L (L1 larvae)] expressing the adherens junction marker ajm-1::gfp in order to visualize cell boundaries in the epithelia. (B,D,F,H,J,L) Corresponding Nomarski pictures. (A,B) Seam cells in wild-type embryos form one line of ten cells (C,D) ceh-16(lg16) embryo (approx. same stage) with disorganized epidermal structure. These animals normally do not elongate and do not hatch. The position of seam cell nuclei and the shape of the embryo are sketched. The initiation of ectopic cell fusion events can also be observed. (E,F) Mosaic analysis: Bean-stage ceh-16(lg16) embryo rescued with ceh-16::gfp. Seam cells that do not express nuclear ceh-16::gfp are misshapen and the boundaries intermingle with dorsal and ventral cells (E, arrows). At this stage the dorsal hypodermis has not yet fused to form a syncytium. (G,H) 1.5-fold ceh-16(lg16) embryo mosaic for ceh-16::gfp. Loss of ceh-16 results in fusion with the dorsal and ventral hypodermis (arrows). (I,J) Same genotype, one cell fusion event is shown (arrow in I). Leakage of internal cells through the epidermis is shown (arrow in J). (K,L) Mosaic (semi-rescued) L1 larva: fusions are shown (arrows in K). At the same position the larva has a lump (arrow in L). Scale bars: 10 µm for embryos; 20 µm for L1 larvae.