Fig. 7

The asymmetric distribution of plasma membrane proteins is maintained in tjp3/zo-3 morphants. (A) Epithelial cell polarization in the EVL. Cryosections of control morpholino (a, c) and tjp3/zo-3 morpholino (b, d) injected embryos at 6 hpf. The EVL, a monolayer of epithelial cells that surrounds the blastoderm, is shown. EVL cells retain their elongated, flattened morphology in the morphants (b, d). These cells are still polarized with adherens junctions along their basolateral membranes, as shown by labeling with anti β-catenin (a, b) and anti pan-Cadherin (c, d) antibodies. Both markers remained restricted to the basolateral surfaces (lateral membranes, arrowheads; basal membranes, arrows). (B) Epithelial cell polarization in the pronephric ducts. Whole mount in situ hybridization of Pax2b (a, b); Immunofluorescence on cryosections: anti-Tjp3/Zo-3 (green) and anti-E-cadherin (red) (c, d); anti-PKCζ (green) and anti-Na⁺/K⁺-ATPase (red) (e, f). Control morpholino 1 dpf (a, c, e): anti-Tjp3/Zo-3 (green) and anti-E-cadherin (red) (c, d); anti-PKCζ (green) and anti-Na⁺/K; tjp3/zo-3 morpholino 1 dpf (b, d, f). In situ hybridization with Pax2b shows that the pronephric ducts extend normally in tjp3/zo-3 morphants (a, b, arrowheads). Morphants lost Tjp3/Zo-3 protein from the apical side of the pronephric ducts as shown above (c, d). E-cadherin staining of the basolateral membranes of the pronephric ducts is maintained in morphants (d, arrows). The polarized distribution of the basolateral Na⁺/K⁺-ATPase (e, f, arrows) and the apical PKCζ (e f, arrowheads) are also maintained in the pronephric duct.