(A–D) The whole brains of Anks1a heterozygous mice at the indicated embryonic or postnatal days were processed for cryostat sectioning. Coronal sections of the brain were subjected to X-gal staining to reveal LacZ-positive cells lining the lateral ventricle. cc, corpus callosum; ChPl, choroid plexus; CP, caudate putamen; Cx, cerebral cortex; LV, lateral ventricle; LW, lateral wall; MW, medial wall. Scale bars, 1 mm. The boxes in A–C were enlarged in A′–C′. Scale bar for A′, 250 μm. (E) The lateral wall (LW) of Anks1a heterozygous mice on P45 was subjected to whole mount X-gal staining. Note that ependymal cells in the LW display prominent X-gal staining. At least three embryos or mice were analyzed at each developmental stages and the results were reproducible.