Fig. 4. Noggin application does not interfere with neural crest specification, but is required for the development of the roof plate and rhombic lip. Expression of the neural crest marker Sox10 (A,D,G, arrows) and of dorsal midline markers Wnt1 (B,E,H, arrow) and Bmp5 (arrow, C,F,I) in control embryos at stage 10 (A-C). The effect of implantation of control CHO cells (D-F) and of Noggin-expressing CHO cells (G-I) was analysed at stage 22. Note that in Noggin-treated embryos Sox10 expression is not affected (G), while expression of Wnt1 and Bmp5 is completely lost at the dorsal midline (arrows, H,I).
