Institute of Molecular Biology, University of Oregon, Eugene, United States
Danielle R Hamill
Department of Zoology, Ohio Wesleyan University, Delaware, United States
Joshua B Lowry
Institute of Molecular Biology, University of Oregon, Eugene, United States
Marie E McNeely
Department of Zoology, Ohio Wesleyan University, Delaware, United States
Molly Enrick
Department of Zoology, Ohio Wesleyan University, Delaware, United States
Alyssa C Richter
Department of Zoology, Ohio Wesleyan University, Delaware, United States
Lauren E Kiebler
Department of Zoology, Ohio Wesleyan University, Delaware, United States
James R Priess
Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States; Molecular and Cellular Biology Program, University of Washington, Seattle, United States; Department of Biology, University of Washington, Seattle, United States
The centriole/basal body is a eukaryotic organelle that plays essential roles in cell division and signaling. Among five known core centriole proteins, SPD-2/Cep192 is the first recruited to the site of daughter centriole formation and regulates the centriolar localization of the other components in C. elegans and in humans. However, the molecular basis for SPD-2 centriolar localization remains unknown. Here, we describe a new centriole component, the coiled-coil protein SAS-7, as a regulator of centriole duplication, assembly and elongation. Intriguingly, our genetic data suggest that SAS-7 is required for daughter centrioles to become competent for duplication, and for mother centrioles to maintain this competence. We also show that SAS-7 binds SPD-2 and regulates SPD-2 centriolar recruitment, while SAS-7 centriolar localization is SPD-2-independent. Furthermore, pericentriolar material (PCM) formation is abnormal in sas-7 mutants, and the PCM-dependent induction of cell polarity that defines the anterior-posterior body axis frequently fails. We conclude that SAS-7 functions at the earliest step in centriole duplication yet identified and plays important roles in the orchestration of centriole and PCM assembly.
