Fig. 10

Compromised osmotic homeostasis mimics the tjp3/zo-3 morphant phenotype. (A) Pericardial edema of tjp3/zo-3 morphants can be reversed by growing the embryos in a hyperosmotic sucrose solution. At 2 dpf tjp3/zo-3 morphants were transferred into a 300 mM sucrose solution. ∼ 80% of tjp3/zo-3 morphants presented with edema (∼ 20% had a curved tail only). If grown in 1x egg water (diamonds), the incidence of edema only slightly decreased, due to individuals that died. However, if tjp3/zo-3 morphants were grown in 300 mM Sucrose (triangles), edema incidence dropped significantly. Mean and S.E.M.; n ≥ 10 per experiment; 5–6 independent experiments. 2-way ANOVA; p < 0.01. (B) Mortality of embryos grown in 300 mM sucrose. Morpholino injected embryos grown in 1x egg water had a mortality of only ∼ 20% at 4 dpf (diamonds), whereas the mortality for controls was very low (open diamonds). Placed in a hyperosmotic sucrose solution at 2 dpf, most morpholino injected (triangles) and control (open triangles) embryos survived up to 3 dpf, when edema incidence was counted. However, after 48 h exposure close to 90% of both control and morphant embryos died. There was no statistical significance between mortality of control or morphant embryos in 300 mM sucrose. Mean and S.E.M.; n ≥ 10 per experiment; 2–6 independent experiments. Two-way ANOVA; p > 0.5. (C) Exposure of WT embryos to high salt conditions mimics the tjp3/zo-3 morphant phenotype. WT embryos in 1x egg water have a straight tail, a wide tailfin and circulating blood (a). Tjp3/zo-3 morphants in 1x egg water presented with curved tail, reduced tailfin (b, arrowheads), the loss of blood circulation and an accumulation of red blood cells (b, arrow). 10–15% of control embryos raised in 100x egg water (c), 20x MgSO₄ (d), 10x NaCl or 20x CaCl₂ (data not shown), also presented with reduced tailfin (c, d, arrowheads), no blood circulation and accumulation of red blood cells (d, arrow).