Fig 6

Fig 6

(A-J) Peripheral nervous system derivatives develop normally in tfec mutants. (A,B) At 4 dpf, the DRG (asterisks) and enteric neurons (arrowheads) number and positioning, as revealed by immunofluorescent detection of Elav1/Hu, is indistinguishable between tfec mutant embryos (B) and WT siblings (A). (C,D) phox2b expression, detected by whole-mount in situ hybridisation, at 72 hpf. The formation and the extent of migration of enteric nervous system progenitors (region between arrowheads) are indistinguishable between tfec mutants and WT siblings. Likewise, expression in the earliest differentiating region of the sympathetic ganglia chain, the superior cervical ganglion (SCG), is unaffected. phox2b expression is also indistinguishable in the hindbrain (white asterisks) and in placode-derived neuronal progenitors in the cranial ganglia associated with the branchial arches (arrows). (E,F) At 48 hpf, sox10 expression analysis showed indistinguishable numbers and distribution of Schwann cells (Sc) occupying the pLLn and spinal nerves. Likewise, oligodendrocyte progenitors throughout the CNS appear normal in their specification, numbers and migration (asterisks). sox10 expression is detectable in iridophore positions (red arrowheads) and in eye iridophores (insets, white arrows), that are strongly affected in homozygous tfec mutants. (G,H) pou3f1 expression analyses at 48 hpf show that glial progenitors on the posterior lateral line nerve (pLLn; area between arrowheads) develop normally in tfec mutants. (I,J) sox10 staining at 30 hpf indicates no observable alterations in the migration of specified neural progenitors through the medial pathway (arrows) in tfec mutants, compared to WT siblings. Likewise, the number and distribution of sox10-positive premigratory NC progenitors (arrowheads) is unaffected. tfec mutants were identified by lack of RPE melanisation (I,J, insets). (K,L) At 30 hpf, dlx2a expression shows that formation of the three streams (s1-s3) of migrating cranial NCCs is unaffected in tfec mutants. Staining is also indistinguishable in the forebrain (f). (M,N) The cranial cartilage at 4 dpf is unaffected in tfec mutants, versus WT siblings, as indicated by Alcian blue staining. Numbered 3–7 are the positions of the branchial arches. (B,H,L,N): tfec^vc60 allele, (D,F,J): tfec^ba6 allele. cb, ceratobranchials; ch, ceratohyal; M, Meckel’s cartilage; nt, neural tube; pq, palatoquadrate. (A-L): lateral views. (M,N): dorsal views. Head towards the left. Scale bars: (A, B, G, H, K-N): 200 μm; (C-F, I, J): 100 μm.