Fig. 4. Neural retinal polarity in Nok deletion mutants. Optical cross sections through the neural retina at 32 hpf. Images represent reconstructions of confocal Z-stack sections. Tissues are stained for ZO-1 (red) and Nok (green). Small insets are magnifications of ZO-1 staining indicated by white arrowheads. (A) The nok^s305 mutant neural retina displays disruptions (white asterisks) and ectopic non-polarized clusters of junction-associated ZO-1 bundles throughout the entire tissue (white arrowhead). (B) Embryos expressing Nok^wt protein within the nok^s305 mutant background display WT retinal polarity. The Nok domains thought to be required for interaction with (C) Patj, (D) Par6, or (F) Crb, as well as (E) the C-terminus of Nok are essential for retinal polarity. All of these deletion mutants display the characteristic nok^s305 mutant phenotype suggesting that Nok functions as an important scaffold for a highly conserved assembly of Crb and Par6-aPKC complex proteins within this tissue.