Figure 7

Two-year old Bbs4^−/−mouse lateral ventricles exhibit ependymal thinning and vacuolization of the neuropil. Neutral red stained coronal sections of 2 yr.-old wild- type (A, C) and Bbs4^−/− brains (B, D) illustrate the progressive nature of the lateral and third ventricle enlargement. TEM micrographs of ependymal cilia of the lateral ventricles of wild- type (E) and Bbs4^−/− mice (F) show reduced numbers of cilia in the mutant mice as well as a mixture of normal and abnormal cilia. Note the presence of typical IFT-like particles and larger vesicle-like material in some Bbs4^−/− cilia (F). Thinning of the ependymal layer of Bbs4^−/− mice (H) is apparent in some regions of the ependyma (G) compared to wild-type mice. Other regions of the ependyma look healthy with intact zona adherens junctions between cells (arrow) but have large vacuoles in the underlying neuropil (I). Asterisks denote the ependymal layer. Bars 1 mm (A-D), 1 μm (E), 0.2 μm (F), 2 μm (G-I).