Fig. 1. Xwnt1 and Xfz3 synergize in the dorsal axis induction assay. (A) Xenopus ectopic axis assay showing synergy between Wnts and frizzleds. RNAs encoding frizzleds (Xfz) and Wnts were injected at low concentrations either alone or in combination into a ventral blastomere of a four- to eight-cell embryo. Secondary axes (indicated by arrows) were scored at the late neurula stage. (B) Summary of screen to identify synergistic Wnt/frizzled combinations. Percent of embryos with ectopic axes is plotted with respect to RNAs injected. The black represents complete axes with cement gland and at least one eye at stage 30. The white represents partial axes. n=61 per combination. Doses of RNA used: Xfz2 (1 ng), Xfz3 (100 pg), Xfz7 (500 pg), Xfz8 (20 pg), mouse Wnt1 (1 pg), Xwnt2b (2.5 pg), Xwnt3A (0.5 pg), Xwnt4 (1 ng), Xwnt5A (200 pg), Xwnt7b (0.1 pg), Xwnt8 (25 pg) and Xwnt11 (500 pg). Synergy in the axis duplication assay was similar for Xenopus and mouse Xwnt1 and frizzled 3 (data not shown).
