Fig 3

(A-C) Transmission electron micrographs of retinal sections from 6 month old wild-type (A) and cep290^fh297/fh297 mutant adults (B, C). Cone outer segments and mitochondria in the ellipsoids are visible in the wild-type retina. In the cep290^fh297/fh297 mutant retinas, cone outer segments are missing or disorganized (arrows) and the outer nuclear layer (ONL, white line) is reduced to 1–2 nuclei. (D, E) At higher magnification, the outer segment disc membranes are tightly stacked in wild-type retinas. In cep290^fh297/fh297mutants, numerous vesicular structures and disorganized membranes are seen in cone outer segments (bracket). Rod outer segments are largely preserved and the connecting cilia are shown (white arrowheads). Scale bars: 10 μm (A-C); 2 μm (D, E).