Fig. 5. The effects of loss and gain of function of Wnt signaling on BrdU incorporation and NC delamination. (A-I) Transverse sections of embryos that received control GFP (A-C), Xdd1 (D-F) or Dep+ (G-I). Upper panels represent GFP immunostaining, central panels are BrdU immunoreactivity, and lower panels depict Hoechst-stained nuclei. (A-C) Electroporation with a control GFP-encoding vector (green) into the hemi neural tube reveals no change in BrdU incorporation (red) when compared with contralateral side. Emigration of GFP+/BrdU+ NC cells is shown (arrowheads). (D-F) Transfection with Xdd1-GFP (green) caused a reduction in number of BrdU+ nuclei (red) and no GFP+ crest cells exiting the treated side of the tube. In D,F, GFP-negative NC cells emigrate from the transfected side. Emigration is normal from the contralateral hemi-tube. (G-I) Dep+ had no effect on either BrdU incorporation or NC emigration. Dep+/GFP+/BrdU+ delaminating cells (arrowheads). NC delamination is also normal from the control side, albeit not seen in this particular section. (J-M) Neural tube explants that received control GFP (J,K) or Wnt1-GFP at 3 µg/µl (L,M). (J,L) An overlay of GFP immunofluorescence (green) onto the phase-contrast images. The white lines depict the border of the tube explants. A larger number of Wnt1/GFP+ NC cells delaminate from the tube and migrate on the substrate when compared with GFP controls. (K,M) GFP in green, BrdU immunolabeling in red and Hoechst nuclear staining in blue. Yellow cells co-express GFP and BrdU. DM, dermomyotome; NT, neural tube; No, notochord; Scl, sclerotome. Scale bar: 35 µm in A-I; 200 µm in J-M.