Fig. 3

a C. elegans CFAP-20 is expressed specifically in ciliated sensory neurons and localises to the inner junction-containing proximal segment of the ciliary axoneme. Shown are fluorescence microscopy images of GFP-tagged CFAP-20 (CFAP-20::GFP) localising to cilia in the head (including amphid/labial neurons) and tail (phasmid neurons). Schematics show the relative locations and structural features of different cilia at the dendritic ends of sensory neurons in the head and tail. PS, proximal segment; DS, distal segment. b Loss of C. elegans CFAP-20 leads to longer phasmid (Kruskal-Wallis and Dunn’s Test; P values: CHE-11::GFP: P values: WT vs cfap-20 = 0.0186; WT vs pcrg-1 = 0.9999; cfap-20 vs pcrg-1 = 0.1634; OSM-3::GFP: WT vs cfap-20 = 0.0001; WT vs pcrg-1 = 0.6374; cfap-20 vs pcrg-1 = 0.0336) but not ASE cilia (one way ANOVA and Tukey Mann test; GFP (ASE): WT vs cfap-20 = 0.4322; WT vs pcrg-1 = 0.1976; cfap-20 vs pcrg-1 = 0.0097). Graphs represent ciliary length measurements using the cilium-localised CHE-11::GFP and OSM-3::GFP fluorescence reporters in phasmid cilia from wild-type animals and pcrg-1 mutants, or soluble GFP marker for ASE cilia. Loss of PACRG (pcrg-1 mutant) does not affect ciliary length. Measurements are from basal body (BB) to ciliary tip for the intraflagellar transport (IFT) markers, and transition zone (TZ) to the ciliary tip for the GFP reporter. Box plots represent minima, 25^th percentile, median, 75^th percentile, maxima. c C. elegans CFAP-20 is required for the structural integrity of the axoneme inner junction. The schematic shows normal ciliary/microtubule ultrastructures at the level of the transition zone, middle segment, and distal segment. Transmission Electron Microscopy (TEM) cross-sections of C. elegans amphid (head) cilia reveal ultrastructure defects in the cfap-20 mutant, namely a break at the inner junction (IJ) in transition zone and middle segment doublet microtubules (examples of the defects shown with white arrows). Source data are provided as a Source Data file.