(A–C) Elongation of the OS (contains the axoneme) and CC (connecting cilium) in Atxn3 KO PhRs, as shown in (A), by rhodopsin (red) and acetylated-α-tubulin (green) detection in isolated rods from 2-year-old WT (Atxn3+/+) and KO (Atxn3−/−) mouse retinas; nuclei were labeled with DAPI (blue) (scale bar, 10 μm); and in (B), by transmission electron microscopy (TEM), where the connecting cilium is indicated by a black line. No other apparent morphological differences were detected (representative images). (C) Mean CC length was 1.897 μm for WT and 2.066 μm for KO (19 TEM pictures, 3 animals per genotype). Two-way ANOVA test (*p < 0.05).
(D–G) The length of primary cilia in ARPE-19 cells is modulated by ATXN3 levels. (D and E) Depletion of endogenous ATXN3 by siATXN3 transfection in human ARPE-19 cells results in longer primary cilium (mean 4.222 μm in siATXN3 cells, n = 41) than that in controls (mean 3.523 μm in siSCR cells, n = 26). Mann-Whitney test (**p < 0.01). (F and G) Starved ARPE-19 cells overexpressing GFP-ATXN3 WT Q22 produce shorter cilia (mean, 3.211 μm) than cells with GFP-ATXN3 C14A mutant (4.208 μm) or the pEGFP empty vector (mean 4.318 μm). Only GFP-positive cells (n > 20–30 per condition) were analyzed (see Figure S5B). Mann-Whitney test (*p < 0.05, **p < 0.01). In (D) and (F), Ciliary microtubules were detected with acetylated α-tubulin (red) and basal bodies with γ-tubulin (green). Scale bar, 5 μm.