Figure 2

Fz4-v1 perturbs morphogentic movements by activation of the Wnt/β-catenin-independent JNK pathway. (A, B) Embryos were injected radially at the 4-cell stage with 1 ng fz4-v1 RNA. At tailbud stages (st. 25) 22% displayed spina bifida and neural tube closure defects (n = 45). (C) At the 4-cell stage 50 pg of the ATF-luciferase reporter plasmid was injected ventral-animally alone, or in combination with 100 pg (low) or 500 pg (high) wnt11 RNA and fz4-v1 RNA (5, 50 and 1000 pg). Reporter activity was analyzed at late gastrula stages (st. 12). Error bars represent SD. (*) indicate significant difference to control or wnt11 alone, respectively (grey bars) (Student’s t test, *p < 0.05, **p < 0.001). (D-H) 4-cell stage embryos were injected at the animal pole region with bvg1 RNA (100 pg) alone, or in combination with fz4-v1 (600 pg) and jnk-apf (1 ng). At blastula stages (st. 9) the caps were explanted and elongation was scored at stage 25. (D) Non-injected controls (n = 20) showed no elongation but bvg1-injected explants (E) did (n = 27). (F) Co-injection of fz4-v1 partially inhibited explant elongation (n = 29), which was restored by JNK-APF (n = 27) (G). (H) Quantification of the animal cap experiments.