Fig. 5

nephrin and podocin morphant embryos exhibit progressive edema, glomerular malformation and podocyte foot process effacement. (A) nephrin and podocin morphant larvae develop severe pericardial edema (arrowheads) at 96 hpf. (B–F) Histological sections of 72 hpf embryos stained with methylene blue/azure II. (B) Normal wild-type glomerulus (gl). Glomeruli in nephrin morphant larva are somewhat flattened (C), and, in approximately 30% of morpholino injected embryos, the glomerulus appears as a midline septum with distended tubules (* in panel D). (E) In cystic nephrin morphants, evidence for obstruction of the pronephric duct could be seen in the presence of large, occluding crystaline deposits (white arrowheads) that completely fill the duct lumen. Particulate debris in the duct lumen was also observed in podocin morphants (F). In contrast to wild-type podocytes (see Fig. 1), nephrin morphant podocytes at 96 hpf show foot process effacement (G) and lack of fine interdigitation. Similarly, podocin morphant podocytes at 96 hpf exhibit irregular processes and foot process effacement (H). At 96 hpf, wild-type podocyte foot processes and slit-diaphragms appear as “beads on a string” (I; arrowheads) along the basement membrane of the capillary wall. nephrin and podocin foot processes at 96 hpf are broad and effaced and lack slit-diaphragms (panels J and K are higher magnifications of the boxed areas in panels G and H).