Figure 3
Delamination and migration of cells from the dorsal neural tube at G15-G17. GFP expression plasmid was injected into the lumen of the neural tube of turtle embryo explants and, electroporated onto one side of the neural tube; the explants were then cultured for up to three days. (A) Dorsal view of G16 trunk explant at 24 hpe. Hindlimbs orientate the explant: anterior to right. (B) G16 explant at 72 hpe demonstrating GFP expression in the neural tube along the length of the trunk-level. Boxed area is shown in higher magnification in (D). (C) G15 GFP explant at 72 hpe showing GFP-positive delaminating and migrating cells from the neural tube. An arrow shows the direction of emigration from the midline of the neural tube. (D) G16 GFP electroporated explant at 72 hpe showing the boxed area in (B). (E) G17 GFP electroporated explant at 72 hpe. (F) Bright field dorsal view of GFP-electroporated G16 trunk explant at 72 hpe stained with anti-GFP antibody. The electroporated side of the neural tube (+) showed delaminating cells along the neural tube. The control side (−) had no GFP-positive cells. (G) A transverse paraffin section of G16 explant at 72 hpe stained with anti-GFP antibody showing GFP-positive cells gathered at the CSA above the neural tube in the carapacial mesenchyme. Boxed area in the CSA is shown in (H) and boxed area in the NT is shown in (I). (H) Cytoplasmic expression of GFP in cells in the CSA. (I) Cytoplasmic expression of GFP in few cells in the dorsal neural tube. hpe, hours post electroporation; CSA, carapacial staging area for neural crest cells above neural tube in carapacial mesenchyme; NT, neural tube. Scale bar approx. 200 μm.
