Fig. 4. Suppression of Wnt signalling in combination with activation of Nodal signalling promotes hypothalamic marker gene expression. Lateral (A,B,C,E,F) and ventral (D) views of brains of embryos at 24-somite stage with anterior to the left in which cells (brown) overexpressing hdl/tcf3a (A,B), axin1 (C), dkk1 (D), madh2CA (E) or madh2CA+dkk1 (F) were transplanted into the prospective hypothalamus/anterior floorplate at 60-65% epiboly. A and B show the same embryo before and after immunohistochemistry for Gfp. In A,B,C,F, black arrowheads point to ectopic nk2.1a expression in the medial floorplate and/or adjacent cells. In B,C,E, red arrows point to cells that integrated in the medial floorplate. In D, Dkk1+ cells (brown) mainly integrate in more lateral positions in the neuroepithelium compared to the Axin1+ and Madh2CA+ cells that integrate in the medial floorplate (brown, red arrows) of the embryos in C and E respectively. Abbreviations: hy, hypothalamus; mb, midbrain; mfp, medial floorplate; pv, posterior-ventral hypothalamus.