Tubulin glutamylation is a post-translational modification that occurs predominantly in the ciliary axoneme and has been suggested to be important for ciliary function1, 2. However, its relationship to disorders of the primary cilium, termed ciliopathies, has not been explored. Here we mapped a new locus for Joubert syndrome (JBTS)3, which we have designated as JBTS15, and identified causative mutations in CEP41, which encodes a 41-kDa centrosomal protein4. We show that CEP41 is localized to the basal body and primary cilia, and regulates ciliary entry of TTLL6, an evolutionarily conserved polyglutamylase enzyme5. Depletion of CEP41 causes ciliopathy-related phenotypes in zebrafish and mice and results in glutamylation defects in the ciliary axoneme. Our data identify CEP41 mutations as a cause of JBTS and implicate tubulin post-translational modification in the pathogenesis of human ciliary dysfunction.
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- Supplementary Text and Figures (8M)
Supplementary Figures 1–14 and Supplementary Tables 1–4
- Supplementary Video 1 (13M)
A small piece of debris in Kupffer's vesicle of a 12 hpf (6 somite) WT embryo is caught moving ciliary currents. The debris (marked by arrow) follows a counter-clockwise circular path around Kupffer's vesicle. nc, notochord; A, anterior; P, posterior; L, left; R, right directions.
- Supplementary Video 2 (4M)
Small pieces of debris in Kupffer's vesicle of a 12 hpf (6 somite) cep41 morphant are caught moving ciliary currents. The debris (within a circle) shows no directional movement, but rather bounces around or stalls. nc, notochord; A, anterior; P, posterior; L, left; R, right directions.
- Supplementary Video 3 (2M)
Movement of cilia at the junction area of the pronephric duct and tubule in a 2.5 dpf WT zebrafish embryo. The observed cilium (an arrow) shows rhythmic undulations. Dashed lines demarcate the outline of the pronephric duct lumen and an arrow point out the observed cilium. A, anterior; D, dorsal; P, posterior; V, ventral directions.
- Supplementary Video 4 (2M)
Movement of cilia at the junction area of the pronephric duct and tubule in a 2.5 dpf cep41 MO-injected embryo. Motile cilium, observed in the WT embryo, is not found. Dashed lines demarcate the outline of the pronephric duct lumen. A, anterior; D, dorsal; P, posterior; V, ventral directions.
- Supplementary Video 5 (11M)
Movement of cilia at the pronephric duct in a 2.5 dpf WT zebrafish embryo. The cilium (an arrow) shows rhythmic undulations. Dashed lines demarcate the outline of the pronephric duct lumen and an arrow point out the observed cilium. A, anterior; D, dorsal; P, posterior; V, ventral directions.