(a) Scheme of the DNA constructs used in the figure. (b) HH-12 chicken neural tubes were analysed 16 (two upper panels) or 39 h (lower panel) after electroporation with aPKCζΔNT·HA. Sections were stained with antibodies against GFP (green, transfection), phalloidin (labels F-actin) or N-cadherin (red) and ZO-1or HA (blue). Arrowheads indicate ectopic accumulation of ZO-1 and N-cadherin. (c) Neural tubes were stained with phalloidin (red), and with antibodies against GFP (green, transfection) and aPKC (blue) 39 h after electroporation with aPKCı alone or plus β-cateninS33Y. Isolated channels are shown in grey scale for a better comparison. (d) Similar experimental conditions as in c but following transfection of aPKCζΔNT. (e) Chicken neural tubes 39 h after transfection with β-cateninS33Y plus pCIG (control), aPKCζK281W or aPKCıK274W (kinase-dead mutants). Sections were stained with antibodies against GFP (green, transfection) and N-cadherin (magenta). (f) The bar graph shows the percentage of sections from the experiment shown in e that presented invaginations and/or a loss of polarity for each treatment. The total number of sections studied (n) in each condition was pCIG=48, aPKCıK274W=62, aPKCζK281W=45. (g,h) Sections of chicken neural tubes were stained with antibodies against GFP (green, transfection), N-cadherin (red) and PH3 (blue) 39 h after electroporation with wild type (aPKCζ, and aPKCı), active (aPKCζΔNT and aPKCıA120E) or kinase-dead (aPKCζK281W and aPKCıK274W) mutants of the ζ and ı isoforms of aPKC. The ratio obtained by dividing the number of PH3+ cells in the electroporated side (EP) by the non-electroporated one (NE) is plotted to the right of each treatment. The number of PH3+ cells counted (n) is displayed within each photogram (white lettering). The bar graphs show the mean±s.d. Significant differences were tested by one-way analysis of variance (ANOVA) followed by the Tukey’s test. Scale bar, 50 μm.