Acute Versus Chronic Loss of Mammalian Azi1/Cep131 Results in Distinct Ciliary Phenotypes

• DOI: 10.1371/journal.pgen.1003928
• Publication Date: 2013-12-26T21:18:29Z
• Authors: Emma A. Hall; Margaret Keighren; Matthew J. Ford; Tracey Davey; Andrew P. Jarman; Lee B. Smith; Ian J. Jackson; Pleasantine Mill
• Keywords: Ciliogenesis; Ciliopathies; Basal body; Motile cilium; Phenocopy

Defects in cilium and centrosome function result a spectrum of clinically-related disorders, known as ciliopathies. However, the complex molecular composition these structures confounds functional dissection what any individual gene product is doing under normal disease conditions. As part an siRNA screen for genes involved mammalian ciliogenesis, we others have identified conserved centrosomal protein Azi1/Cep131 required cilia formation, supporting previous Danio rerio Drosophila melanogaster mutant studies. Acute loss Azi1 by knock-down mouse fibroblasts leads to robust reduction which rescue expressing siRNA-resistant Azi1-GFP. Localisation studies show localises centriolar satellites, traffics along microtubules becoming enriched around basal body. also transition zone, structure important regulating traffic into ciliary compartment. To study requirement during development tissue homeostasis, null mice were generated (Azi1Gt/Gt). Surprisingly, Azi1Gt/Gt MEFs no discernible phenotype moreover are resistant knock-down, demonstrating that compensation mechanism exists allow ciliogenesis proceed despite lack Azi1. Cilia throughout functionally normal, embryonic patterning adult homeostasis grossly unaffected. highly specialised sperm flagella, not compensated, leading striking microtubule-based trafficking defects both manchette resulting male infertility. Our analysis (acute loss) versus deletion (chronic suggests plays conserved, but non-essential role ciliogenesis. Importantly, our vivo reveals mediates novel functions necessary flagellogenesis. highlights importance acute removal protein, addition knock-out studies, when characterising candidates human disease.