Centrobin controls primary ciliogenesis in vertebrates

The BRCA2 interactor, centrobin, is a centrosomal protein that has been implicated in centriole duplication and microtubule stability. We used genome editing to ablate CNT ROB in hTERT-RPE1 cells and observed an increased frequency of monocentriolar and acentriolar cells. Using a novel monoclonal antibody, we found that centrobin primarily localizes to daughter centrioles but also associates with mother centrioles upon serum starvation. Strikingly, centrobin loss abrogated primary ciliation upon serum starvation. Ultrastructural analysis of centrobin nulls revealed defective axonemal extension after mother centriole docking. Ciliogenesis required a C-terminal portion of centrobin that interacts with CP110 and tubulin. We also depleted centrobin in zebrafish embryos to explore its roles in an entire organism. Centrobin-depleted embryos showed microcephaly, with curved and shorter bodies, along with marked defects in laterality control, morphological features that indicate ciliary dysfunction. Our data identify new roles for centrobin as a positive regulator of vertebrate ciliogenesis.