Fig. 5. Localization of Nok deletion proteins within myocardial cells. Images represent reconstructions of confocal Z-stack sections imaged on 32 hpf Tg[cmlc2:GFP] transgenic myocardial cells of (A-F) nok^s305 mutant embryos expressing different Nok deletion proteins, (G) WT, or (H) ome^m289 mutant. ZO-1 (blue) and Nok (red) label apical cell junctions. (A) Apical junctions are lost and ZO-1-positive belts are missing in nok^s305 mutant embryos. (B) ZO-1-positive apical junctions are present and myocardial organization is restored in nok^s305 mutant embryos injected with mRNA encoding Nok^wt protein which colocalizes with ZO-1 at apical junction belts (white arrowheads). (C) ZO-1-positive apical junctions are present and myocardial organization is restored in nok^s305 mutant embryos injected with mRNA encoding Nok^PatjLin7 which is consistent with the rescue of cardiac morphology by this deletion protein. The deletion protein colocalizes with ZO-1 at apical junctions (white arrowheads). The Nok domains required for interaction with (D) Par6, (E) Crb or (F) the C-terminus of the protein are functionally required for apical junction maintenance and myocardial organization. Although each deletion protein is diffusely expressed within the cytoplasm, ZO-1-positive apical junctions are missing. (A'-F') Nok protein localization is shown in gray. Whereas endogenous Nok protein colocalizes with ZO-1 to apical junctions in WT (G), it is mislocalized in ome/crb2a^m289 mutant myocardial tissue (H). Orientation: all images are apical views.