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Fig. 2. Overexpression of Pax3 and Zic1 induces ectopic expression of neural crest markers. Synthetic mRNA was injected into two left animal blastomeres (A-L) or into the ventral animal blastomeres (M-P) at the eight-cell stage. Embryos were harvested at stage 15 and subjected to in situ hybridization with Foxd3 (A,D,G-M,O,P), Slug (B,E,N), Zic1 (C) and Pax3 (F) probes. Pax3 mRNA injection (50 pg/cell; A-C), Zic1 mRNA injection (50 pg/cell; D-F), Pax3-GR mRNA injection (100 pg/cell; G-I), Zic1-GR mRNA injection (100 pg/cell; J-L), and injection of both Pax3 and Zic1 mRNAs (50 pg/cell each; E-H) with lacZ mRNA (200 pg/cell). Dexamethasone (Dex; 10 μM) was added to culture solution at stage 10.5 (H,K) or stage 12 (I,L). Arrows in A,B,H,K,M and N indicate ectopic expression of each marker gene. |
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Fig. 5. Co-activation of Pax3 and Zic1 in concert with Wnt signaling is essential for neural crest determination of the ectoderm in vivo. (A-F) Synthetic mRNA was injected into a ventral animal blastomere at the eight-cell stage. Embryos were harvested at stage 15 for in situ hybridization with Foxd3 (A,C,E) or Slug (B,D,F) probes. A higher magnification view is shown in the right half of each panel. Pax3 and Zic1 mRNA injection with lacZ mRNA (A-F; β-gal activity was visualized by incubating with Red-Gal), β-catenin-MO (Gene Tools; 10 ng/cell; C-F), and β-catenin (50 pg of DNA/cell; E,F). |
