Whirlin knockout mice have morphological defects around the PMC in photoreceptors revealed by electron microscopy.

<p>(A) A representative image showing the normal ultrastructure around the PMC in the wild-type photoreceptor (whirlin^+/+). (B–F) In whirlin knockout mice (whirlin^−/−), abnormal distance (E) and membrane fusion (empty arrows, B–E) between the apical inner segment and the connecting cilium were found. In addition, a large amount of vacuoles (filled arrows, D–F) were accumulated around the PMC. (D,D′) show the same cell at different sectioning levels. OS, outer segments; CC, connecting cilia; IS, inner segments. Scale bars, 200 nm. (G) All the above abnormalities exist in a small fraction of photoreceptors randomly distributed in the retina of whirlin knockout mice. The number of mice analyzed in each group is indicated in the bottom of each bar. Mean ± SEM; **, p<0.01.