Fig. 3. Loss of aPKC impairs cell cycle-dependent nuclear positioning. (A,B) Nuclei of cells in S-phase of cell cycle are labeled using BrdU antibody (red), and mitotic cells are labeled with phospho-histone H3 antibody (green) on confocal sections of the neocortical region. Brains were dissected from control (A) and aPKC cKO (B) embryos at E15.5, 2 hours after administration of BrdU. Scale bars: 10 µm. (C-E) Distributions of BrdU positive or mitotic cell nuclei in each layer were quantified and graphed. Total numbers of BrdU-positive nuclei in neocortical layers are not significantly changed by loss of aPKC (C). The large majority of BrdU-positive nuclei in aPKC cKO and control embryos are located in the subventricular zone and ventricular zone (SVZ/VZ) (D). With the SVZ/VZ divided into three layers, differences in distribution of BrdU-labeled nuclei in each layer are obvious between control and aPKC cKO embryos (D). ^*P<0.01. Cells dividing in non-surface areas are greatly increased in aPKC cKO embryos (E).