Figure 3

Transmission electron micrograph of Crx-/- retina at P21 (A and B), and scanning electron micrograph of Crx-/- at P10 (C) of outer segment layer. (A) Evidence of ciliogenesis in the photoreceptor layer of Crx-/- retina. Nonmotile connecting cilia were observed in cross section (arrowheads 1,2, and 3, for examples). Connecting cilium 1 (arrowhead 1) demonstrated seven microtuble doublets, while cilium 2 and cilium 3 exhibited nine. In A, a displaced cell nucleus (n) appearing pyknotic and abnormal deposition of matrix (mx) material of unknown identity were seen, along with large amounts of membranous vesicles (arrow) which filled the photoreceptor space and appeared to be released from inner segments. Scale bar = 3.7 μm. (B) Nonmotile connecting cilium in cross section, from a Crx-/- photoreceptor, demonstrating characteristic 9+0 radial array of microtubule doublets. Scale bar = 88 nm. (C) Scanning electron micrograph (SEM) of membranous vesicles (arrow shows one example) shed from inner segments of Crx-/- photoreceptors at P10. Figure shows inner segments viewed from the scleral side with the pigmented epithelium removed. Scale bar = 1 μm.