Fig. 4. Loss of aPKC causes retraction of apical process in neuroepithelial cells. (A) Immunofluorescence for -tubulin (red) and nuclei (blue) on confocal sections of the neocortical region in control (left panel) and aPKC cKO embryos (right panel) at E15.5. (B) Cell shape of neuroepithelial cells was examined by DiI labeling. Slice cultures were prepared with telencephalic vesicles of control (left panels) and aPKC cKO embryos (right panels) at E15.5. Phase-contrast images of slice cultures are also shown (phase). Broken white lines indicate pial surface of slice culture, and the ventricular surface is shown by broken black lines. Asterisks indicate pial end of cell process with DiI mass. Arrowheads indicate position of cell body, and an arrow indicates retracted apical cellular process in slice culture prepared from an aPKC cKO embryo. (C) Quantitation of neuroepithelial cell morphology. Most cells attach to the ventricular surface in control embryos; however, these cells are rare in aPKC cKO embryos. (D) Time-lapse image of a DiI-labeled neuroepithelial cell in a slice culture prepared from aPKC cKO embryo at E15.5. Apical tip of a cellular process indicated by arrows is detached from the ventricular surface and shortened progressively. LV, lateral ventricle. Scale bars: 10 µm.