Fig. 5: Expression of mutant usherin leads to shortening of the photoreceptor cilium.

A Retinal sections labeled with the CC marker Cen2 revealed a decrease in CC length in the Ush2a^delG/delG retina. B Measurement of the ciliary length revealed statistically significant shortening at P30 Ush2a^delG/delG mice (359 cilia were measured from three independent WT and Ush2a^delG/delG mice). The acetylated region of the photoreceptor cilium is also significantly reduced (177 and 175 cilia were measured from three separate WT and Ush2a^delG/delG mice, respectively). Significance was determined by a two-tailed unpaired t-test, p < 0.0001 (****). C Measurements of the ciliary length revealed the shortening to be significant in P300 Ush2a^delG/delG mice (208 and 210 cilia were measured from two separate WT and Ush2a^delG/delG mice, respectively). Significance was determined by a two-tailed unpaired t-test, p < 0.0001 (****). Data presented in B and C are means ± SD. D Representative TEM images of the OS/IS junction (upper images) and higher magnification images of the CC (lower images) from P360 WT and Ush2a^delG/delG mice are shown. E A photoreceptor schematic denoting the areas at which measurements of OS and CC widths were made. F The width of OS and CC was quantified in P360 WT and Ush2a^delG/delG retinas. The width of the OS was significantly reduced in the Ush2a^delG/delG retina, while the width of CC remained unchanged (68 cilia were measured for WT and 90 cilia were measured for the Ush2a^delG/delG). Shown are means ± SD. Significance was determined by a two-tailed unpaired t-test, p < 0.0001 (****) for OS width. G High magnification TEM images are taken from P360 WT and Ush2a^delG/delG mice showing a cross-section of the CC. OS outer segment, CC connecting cilium, IS inner segment, PR periciliary region, OSW outer segment width, CCW connecting cilium width.