Figure 6.

Structural abnormalities are present in the ependymal cilia of Bbs2^−/−, Bbs4^−/−, and Bbs6^−/−mice. TEM micrographs illustrate the presence of vesicular-like inclusions and electron-dense material in a sub-population of BBS mutant mouse ependymal cilia lining the enlarged lateral ventricles (A,B, D-F) and 3^rd ventricles (C, G, H) in 4 month-old Bbs2^−/− mice (A, D), 2 month-old Bbs4^−/− mice (B, E, F) and 8 month-old Bbs6^−/− mice (C, G, H). In some cilia, these structural abnormalities appear slightly distal to the transition zone between the basal body and the ciliary axoneme (A) while in others bloating of cilia is observed (B, C). Cross-sections illustrate disruption of the 9 + 2 axoneme in a subpopulation of cilia. Note the broken radial spokes that attach the peripheral microtubule doublets to the central pair, and the broken nexin links that connect the peripheral microtubule doublets (D-H). Arrows point to disrupted axonemes in E, F, G (lower region), and H. Typical IFT-like particles are denoted by an arrow in (C). TZ (transition zone). Bars, 1 mm (A-D), 0.5 μm (E-L).