Fig. 7

mos^m188 mutants lack foxd3 expression in NC precursor cells. Lateral views of wild-type embryos and mos^m188 mutants stained with a foxd3 riboprobe (anterior is to the left). A,B:foxd3 expression at the tail bud stage (10 hpf) in wild-type embryos (A) is localized to the future hindbrain cranial neural crest precursors and to the tail bud domain (tb). foxd3 is not expressed in the NC precursors in mos^m188 mutants (B) and only faintly in the tail bud domain. C,D: In wild-type embryos (C), cranial and trunk premigratory neural crest cells express foxd3 at the 8-somite stage (13 hpf; arrow points to the posterior edge of the otic placode). Expression is also visible in the somitic precursor cells (arrowheads), and in the tail bud (tb). Expression in mos^m188 mutants (D) is restricted to the somites (arrowheads). E,F: The foxd3 message levels in wild types (E) is downregulated in the cranial NC, but it is still maintained in the trunk premigratory NC at the 18-somite stage (arrow, 18 hpf), in the somites (arrowheads), and in the late migrating neural crest precursors around the otic vesicle (ov, arrow). In mos^m188 (F), expression is only detected in the somites (arrowheads). G,H: At 24 hpf, decreasing numbers of cells express foxd3 in the most posterior somites of wild-type embryos (Lee et al.,[2006]; arrowhead in G). At this time, foxd3 expression of the NC is confined to the two domains located anterior and posterior to the otic vesicle (arrows) that will contribute to neural derivatives. In the mos^m188 mutants (H), the somites continue expressing foxd3 (arrowhead), while there is no expression in the cranial and trunk NC progenitors. I,J: The antibody against zebrafish Foxd3 protein marks the two domains at the neural plate border (arrow) where NC progenitors are located at 11.5 hpf (4-somites) in wild types, while there is no detectable protein in mos^m188 mutant embryos at this stage (J). K,L: At 19 hpf, wild-type but not mos^m188 mutant neural crest, seen at the most distal part of the tail, express Foxd3 protein, while there is no difference in somitic expression.