Figure 2

Differential expression of Wnt ligands and Wnt pathway components in the late primitive streak. (A) Wnt3a in situ hybridisation, white lines indicate the levels of section in (B) through the anterior streak with staining in the neural plate (C), section through the posterior streak with low levels of Wnt3a transcripts. (D) Wnt5a in situ hybridisation, white lines indicate the levels of section in (E) through the anterior and (F) through the posterior streak indicating widespread expression of Wnt5a in neural plate and mesoderm. (G) Wnt8c in situ hybridisation, white lines indicate the levels of section in (H) through the anterior and (I) through the posterior streak indicating expression of Wnt8c in neural plate and mesoderm. (J) Dishevelled-1 was not expressed in posterior regions of HH9 embryos but (K) dishevelled-3 and (N) prickle-1 showed similar expression in neural folds, lateral plate mesoderm and low levels in the primitive streak White lines indicate the levels of section in L, O (anterior), M and P (posterior) streak of dishevelled-3 and prickle-1. HH stage is indicated on each panel. hn, Hensen's node; m, mesoderm; nf, neural fold; np, neural plate; nt, neural tube; ps, primitive streak; * asterisks indicate position of the node.