Fig. 4. Loss of aPKC function expands basolateral membrane domain into the apical side and disrupts the apical domain. (A) The aPKC NT construct has the Par6-binding site but no kinase domain and so acts as a dominant-negative fragment. (B) The effect of this construct can be rescued by overexpressing full-length aPKC. Injections of 4.5 ng aPKC NT + 0.5 ng GFP, 4.5 ng aPKC NT + 0.5 ng aPKC, or 5 ng GFP were carried out. The average of four experiments scored blind is shown. (C,D) aPKC NT dominant-negative fragment caused pigment defects (D) compared with control (C) (5 ng of each). (E,H) aPKC NT was co-injected with GFP showing that the pigment defects occurred in the injected region. The arrows in C,E and D,H highlight the same cells. (F-J) aPKC NT (I,J) caused ectopic localisation of the basolateral markers ß1-integrin and occludin to the apical side (arrow) and tight junctions were also lost (J, arrowhead) when compared with GFP control (F,G). (K) Diagram of the observed phenotype. Colours are as above. Pigmented embryos were injected as this allowed the affected area to be easily identified, they were then fixed and stained for markers of cell polarity.