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Fig. 2. Ednra is required for neural crest development. (A–I) Efficiency of Ednra antisense morpholino oligonucleotide. (A) EdnraMO inhibits in vitro translation of Ednra in a dose-dependent fashion. Arrow indicates Ednra protein product. (B–I) EdnraMO inhibits in vivo expression of Ednra–GFP. (B,C) Embryos injected with mRNA encoding Ednra–GFP (1 ng/embryo) showing GFP fluorescence. (D,E) Embryos injected with Ednra–GFP mRNA (1 ng/embryo) and CoMO (30 ng/embryo). (F–I) Embryos injected with Ednra–GFP mRNA (1 ng/embryo) and EdnraMO (F–G, low dose, (l) 10 ng/embryo; H–I, high dose (h), 20 ng/embryo). No embryo shows GFP fluorescence at high dose. White arrows indicate the injected side. (J–S) Analysis of the formation of neural crest derivatives. Normal melanocyte formation (J, arrows) and Trp2 expression (M, arrows). EdnraMO-injected embryos show inhibition in melanocyte development (K) or Trp2 expression (N). The melanocyte formation was completely rescued by the coinjection of EdnraMO and Ednra′ mRNA (L). Induction of melanocytes in vitro by conjugating animal caps with prospective paraxial mesoderm cultured until the equivalent of St. 38. Control conjugates show melanocytes (O, arrows). Conjugates prepared with a 10 μM BQ123-soaked bead show no melanocyte formation (P). EdnraMO-injected (Q, arrowhead) embryos present a reduction of Meckel's and ceratohyal cartilages. (R) Schematic representation of EdnraMO effects on Xenopus head cartilages. M, Meckel's cartilage; Ir, infrarrostral; CH, ceratohyal; BH, basihyal; CB, ceratobranchial. (S) Normal cartilage formation was completely rescued by the coinjection of EdnraMO and Ednra′ mRNA. |
