Fig. 3. Morphology and origin of NS-divisions in vivo. (A) Double immunostaining of an E13 cerebral wall section with phosphorylated vimentin (p-vim) and pH3, showing two pia-connected, unipolar-shaped dividing cells (one of them is magnified in A'). (B) A serial section (20 µm thick) from an E14 cerebral hemisphere subjected to GFP-adenovirus injection into the lateral ventricle 19 hours earlier visualized under a fluorescent microscope. Anti-GFP antibody detected only the indicated mitosis (telophase, strongly positive for Ki67; B') in three serial sections. (C) Visualization of cerebral wall sections from embryos infected with GFP-adenovirus demonstrates GFP⁺ cells in both S and NS positions. Scale bars: 10 µm in A,C; 100 µm in B.