Fig. 6. Analysis of epithelial integrity in nok mutants. (A-L) Transverse sections through brains of wild-type and nok embryos at 17 hpf (A,B) or 22 hpf (C-L). (A,B) A clear midline is visible in wild type (A; arrow) but cells are disorganized in nok (B). (C,D) Labeled with PH3 antibody (mitosis marker) (green) and actin (red), dividing nuclei localize apically in both wild type (C) and mutant (D). (E,F) Labeled with ß-catenin antibody; (G,H) labeled with actin marker, phalloidin-Texas Red; (I,J) labeled with occludin antibody and phalloidin-Texas Red counterstain; (K,L) high magnification of 3D compilation of transverse sections through forebrain, labeled with phalloidin-Texas Red. In the nok mutant, all junction markers localize apically as in wild type but show disorganization. (M,N) Nok antibody labeling (green) at 22 hpf in horizontal section through midbrain and hindbrain of wild type (M) and nok mutant (N), with phalloidin-Texas Red as counterstain (red). Scale bar: 20 µm.