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Fig. 9. Ednra in the genetic cascade that specifies the neural crest. Ednra lies downstream Msx1 and upstream Sox9–Sox10. (A–O) Representative examples of embryos injected with the indicated reagents. The graphs at the right side represent the percentage of embryos with the indicated phenotypes; the letter in each column correspond to the treatment described for each figure in panels A–O. (A, B) Embryos injected with Msx1-GR show increased expression of Ednra and neural crest marker FoxD3. (C) Msx1-GR construct failed to increase the expression of FoxD3 marker when was coinjected with EdnraMO. (C') EdnraMO leads to a reduction of FoxD3 expression in the injected side (arrowhead). (D, E) Msx1-dominant negative inducible construct (HDMsx1-GR) inhibited the expression of Ednra and FoxD3. (F) The coinjection of dominant negative HDMsx1-GR construct and Ednra mRNA rescue the expression of FoxD3 in the neural crest. (F') Ednra overexpression leads to an increased FoxD3 expression in the injected side (arrowhead). (G) No changes in the expression of Msx1 was observed in embryos microinjected with Ednra mRNA. (H, I) Ednra mRNA-microinjected embryos show expanded expression of Sox9 and Sox10 in the injected side (arrowhead). (J–L) EdnraMO-microinjected embryos show no effect on Msx1 (J), but inhibition of Sox9 (K) and Sox10 (L) expression in the injected side (arrowhead). (M–O) Sox9 mRNA and Sox10 mRNA rescue FoxD3 expression in EdnraMO-injected embryos. (N') Expansion of FoxD3 in embryo injected with Sox9. (O') Expansion of FoxD3 in embryo injected with Sox9. |
