Fig. 2

The mos^m188 mutation affects migratory cranial neural crest. A,B:dlx8 expression was analyzed by in situ hybridization at 36 hpf in the craniofacial primordia of wild-type (A) and mos^m188 (B) embryos. In mos^m188mutants, expression appears slightly reduced in the first primordium but it is faint in the second (arrow in all panels) and absent in the posterior streams. C,D: Dorsal view of dlx2 expression at 24 hpf shows markedly reduced expression in the first two neural crest streams and almost complete absence in the postotic ones. E,F: Expression of the paraxial mesoderm and head mesenchyme marker wnt5a is substantially reduced at 24 hpf in the second and posterior NC streams in the mos^m188 mutants while the first arch expression appears unaffected. G,H: The expression of sox9a, a marker of cranial mesenchymal condensations, is reduced in the first arch and is completely abolished in the second and posterior arches (24 hpf). I-L: The hox gene expression in hindbrain rhombomeres (r) is comparable between wild-type (I, K) and mos^m188 (J, L) embryos, but expression of hoxa2 in the hyoid neural crest stream is largely absent, (arrow, J). Expression of hoxa2 and hoxb3 in the postotic stream is considerably reduced (white arrowhead in I,L).