Fig. 7

Wnt8b and Lef1 act through the canonical Wnt pathway in the posterior hypothalamus. White circles outline posterior hypothalamus in whole-mount views, and black ovals outline posterior hypothalamus in cross-sections. (A,B) At 30 hpf, wnt8b (blue) and lef1 (red) show overlapping and adjacent expression in the posterior hypothalamus. (C-F) In wnt8b morphants, sox3, zash1a, dlx2 and isl1 expression are specifically reduced in the posterior hypothalamus at 30 hpf. (G-I) A transgenic reporter for ß-catenin-mediated transcription (TOPdGFP) shows mRNA expression in the posterior hypothalamus (red) at 24 hpf. In the posterior hypothalamus, wnt8b expression (blue-H) partially overlaps with gfp, whereas lef1 (blue-I) almost completely overlaps with gfp. (J-O) In TOPdGFP embryos, GFP protein (brown) is expressed in the posterior hypothalamus. At 24 hpf (J-L) and 30 hpf (M-O), this expression is absent in wnt8b and lef1 morphants.