Fig. 6

Dorsal gene expression increases in hec mutant embryos upon injection of upstream components of the Wnt/β-catenin pathway. (a–b) Injection of β-catenin mRNA leads to the appearance of dorsal structures in hec mutant embryos (24 hpf; anterior to left). (c–f) The frequency of embryos expressing goosecoid increases after injection with β-catenin RNA (c), dominant negative GSK-3 RNA (XG114) (d), GSK-3 binding protein RNA (e), and zWnt8 + FzA RNAs (f). “Wild-type gsc” refers to the presence of staining in a pattern similar to that seen in similarly staged uninjected wild-type embryos. “Ectopic gsc” refers to the presence of staining in regions in the margin outside the normal wild-type pattern. Presence of staining in a portion of the uninjected hec mutant embryos is due to the differences in expressivity of the phenotype. Injection of β-galactosidase mRNA does not lead to an increase in dorsal gene expression (data not shown).