||Supplementary Figure 3. Expression of Wtip and Pk3 in Xenopus early embryos. GRP explants and whole embryos were subjected to wholemount in situ hybridization with Wtip or Pk3 anti-sense or control sense RNA probes as indicated. (A, B) Stage 10+ gastrulae. Wtip transcripts are weakly detected in the animal pole ectoderm when
compared to the embryo hybridized with the corresponding sense probe. Animal pole is up. (C-E) Stage 18 neurulae. Wtip transcripts are detected in both neural and non-neural ectoderm. The neural folds and the neural crest area are strongly positive. (A-E) Anterior is to the left. (A, B, D) Lateral view, (C, E) dorsal view. (F, G) Both Pk3 and Wtip RNAs are present in the ventral side of GRP explants that were prepared prior to in situ hybridization from stage 17/18 embryos. For both anti-sense
probes, staining appears stronger at the midline than in the adjacent endoderm. Ventral view is shown, anterior is up. (H-J) Transverse sections of the explants shown in (F, G). Wtip RNA is predominantly in the neural tissue, with lower levels in the GRP (arrow) and the mesoderm (I). Pk3 transcripts are present at the GRP midline (arrow), epidermis and the superficial layer of the neural plate (J). Notochord, N, is indicated by dashed outline.