NcKO mice show severe hypoplasia of the cerebral cortex and have no hippocampus or cerebellum. (A) The appearance of control (Ctrl) and NcKO mice at P0. NcKO mice exhibited small eyes (arrow) and internal hemorrhaging (arrowhead). (B) Representative brains of the P14 Ctrl and NcKO mice. The NcKO brain shows hypoplasia of the cerebral cortex (arrow) and has no cerebellum (arrowhead). Scale bar, 5 mm. (C–H) Hematoxylin-eosin staining of coronal sections in the middle (C and F) and caudal region (D and G) and sagittal sections of the cerebellum (E and H) at E16.5 (C–E) and P0 (F–H). Asterisks, arrows, and arrowheads in C and F indicate the cerebral cortex, hippocampus, and third ventricle, respectively. Arrows and arrowheads in D and E indicate the vermis of the cerebellum (Cb) and middle part of the midbrain (Mb), respectively. Asterisks in G and H indicate the enlarged aqueduct of the midbrain and the fourth ventricle, respectively. Scale bars, 1 mm. (I) Immunoblots showing SNAP23 and SNAP25 in the brain. GAPDH blotting was used as a loading control. (J and K) Nissl staining in coronal sections of the cerebrum and sagittal sections of the cerebellum at E12.5 and E13.5. Arrows indicate the disorganization of the ventricular walls. Scale bars, 200 µm (J), 100 µm (K). (L and M) Expression of SNAP23 in E13.5 brain sections. Scale bars, 50 µm. 4th V, fourth ventricle; CP, cortical plate; EGL, external granular layer; LV, lateral ventricle; RL, rhombic lip; VZ, ventricular zone.