Figure 1

Fz4-v1 has a biphasic, dose-dependent activity in modulating Wnt/β-catenin-dependent signalling. (A-F) 4-cell stage embryos were injected on the ventral marginal side with 0.5 pg wnt8b RNA (lo) or 10 pg (hi) alone, or in combination with 250 pg fz4-v1 RNA (lo) or 1000 pg (hi) or with 250 pg (lo) or 1000 pg (hi) fz4-v1 RNA alone. Formation of secondary body axes was scored at neurula (st. 20, B-F) and tadpole stages (st. 38, B’-F’). Frequency of secondary axis formation: (B, B’) 71.9% (n = 36), (C, C’) 0% (n = 24), (D, D’) 0% (n = 20), (E, E’) 0% (n = 24), (F, F’) 54.2% (n = 24). (G) At the 4-cell stage blastomeres were injected in the animal region with 80 pg Topflash-Luciferase reporter plasmid in combination with wnt3a RNA (0.05 pg, 0.1 pg, 5 pg) and fz4-v1 RNA (5 pg, 50 pg, 1000 pg). (H) Luciferase activity was measured at gastrula stage (st. 11). Error bars represent standard deviation (SD). (*) indicates significant difference (Student’s t test, p < 0.05).