Fig. 1

Differential cellular characteristics of the neural tube at neural crest (NC) and roof plate (RP) stages. a, b Transverse sections of the flank region of E4.5 avian embryos whose hemi-neural tubes (NTs) were electroporated with a control GFP plasmid at E2 (a) or E3.5 (b). Note the contribution of labeled cells to NC derivatives including melanocytes (arrow in a) following early but not late stage electroporations. c, d Bromodeoxyuridine (BrdU) incorporation following a 1-h pulse at NC (E2–E2.5, c) or RP (E3.5, d) stages. Dashed lines in insets mark the dorsal NT domain that was quantified (see text for details). Note the presence of the BrdU+ nuclei (Red) in c–c” but not in the equivalent dashed area in d–d”. Nuclei were visualized with Hoechst. e–j Antibody staining for epithelial (ZO-1, N-cadherin, laminin) or ciliary (Arl13b) markers. Arrows point to disorganized cilia (e’), the absence of N-cadherin in the dorsal NT compared to more ventral regions (g), and an incomplete laminin-containing basal lamina (i, i’) at the NC stage. In contrast, note the apically oriented cilia (f), positive N-cadherin immunostaining (h), and continuous laminin expression (j) in the dorsal NT at the RP stage (arrowheads in f, h, and j’). Ect ectoderm. Bar in a, b, d, h, j = 80 μM; c = 50 μM; c’, d’, e = 30 μM; f, g, i’ = 40 μM; e’ =15 μM; j = 240 μM; i =140 μM