Fig. 5. Ectopic activation of the canonical Wnt pathway induces zic gene transcription. (A-C) Embryos were injected with hs:ßCat-gfp DNA, heat shocked at shield-stage, and assayed for zic2a (purple) and gfp (orange) at late-gastrula. (A) ßCat-gfp is expressed in the medial neural plate; the zic2a pattern is normal (no ectopic expression; n=10, two experiments). (B,C) ßCat-gfp is expressed in lateral ectoderm; zic2a is ectopically expressed (arrows; n=8, 8 ectopic, two experiments). (D) Control embryo expressing hs:gfp in lateral ectoderm showing no ectopic zic2a expression (n=18, 0 ectopic, one experiment). a, anterior. (E-G) Zic2aD5:gfp embryos injected with GR-Lef RNA and assayed for gfp RNA at late-gastrula (purple). (E) GR-Lef-injected embryo showing weak ectopic gfp (arrow). (F,G) GR-Lef-injected embryos treated with DEX (F) or DEX and CHX (G). (H) Uninjected zic2aD5:gfp control treated with DEX. (I) Summary of GR-Lef overexpression experiments, showing the proportion of embryos expressing gfp for each treatment condition. The number of embryos scored for each condition is listed along the x-axis.