Embryonic day 13.5 Lis1^+/− mouse brains have reduced PNEI and delayed NEBD. (A) Parasagittal sections through embryonic day 13.5 cortices from wild-type (WT) and Lis1^+/− mice stained with LAP2 (green), H3 (red), and Hoechst (blue). (B) Enlargement of VZ. (C) Interphase (I) cells lack H3 staining and have intact NEs. Prophase (P) cells had an intact NE, sometimes with invaginations (PI). Prometaphase (PM), NE disrupted and chromosomes not aligned. Metaphase (M) and telophase/anaphase (T/A) cells were categorized by chromosome arrangement. (D) The percentage of prophase cells with PNEI was decreased in Lis1^+/− animals. Three sections per animal were analyzed. Error bars indicate the mean ± SD for three animals per genotype. (E) Lis1^+/− animals (blue) had more prophase (pro) and fewer prometaphase cells (promet) than wild-type littermates (brown). (F) A prophase cell in a wild-type embryonic day 13.5 brain stained for Lis1 (green) and LAP2 (red). (right) LAP2 (red) and Hoechst (blue). Arrows indicate prophase cells at the VZ. (D and E) Significance determined by Student's t test. Error bars indicate ±SD. Bars: 20 μm (A); 10 μm (B); 2.5 μm (C); 5 μm (F).