title: Modelling a ciliopathy: Ahi1 knockdown in model systems reveals an essential role in brain, retinal, and renal development.
abstract: Joubert syndrome and related diseases (JSRD) are cerebello-oculo-renal syndromes with phenotypes including cerebellar hypoplasia, retinal dystrophy, and nephronophthisis (a cystic kidney disease). Mutations in AHI1 are the most common genetic cause of JSRD, with developmental hindbrain anomalies and retinal degeneration being prominent features. We demonstrate that Ahi1, a WD40 domain-containing protein, is highly conserved throughout evolution and its expression associates with ciliated organisms. In zebrafish ahi1 morphants, the phenotypic spectrum of JSRD is modeled, with embryos showing brain, eye, and ear abnormalities, together with renal cysts and cloacal dilatation. Following ahi1 knockdown in zebrafish, we demonstrate loss of cilia at Kupffer's vesicle and subsequently defects in cardiac left-right asymmetry. Finally, using siRNA in renal epithelial cells we demonstrate a role for Ahi1 in both ciliogenesis and cell-cell junction formation. These data support a role for Ahi1 in epithelial cell organization and ciliary formation and explain the ciliopathy phenotype of AHI1 mutations in man.
authors.affiliation: Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
authors.forename: Roslyn J
authors.initials: RJ
authors.lastname: Simms
authors.forename: Ann Marie
authors.initials: AM
authors.lastname: Hynes
authors.forename: Lorraine
authors.initials: L
authors.lastname: Eley
authors.forename: David
authors.initials: D
authors.lastname: Inglis
authors.forename: Bill
authors.initials: B
authors.lastname: Chaudhry
authors.forename: Helen R
authors.initials: HR
authors.lastname: Dawe
authors.forename: John A
authors.initials: JA
authors.lastname: Sayer
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000196:embryology*; D002352:Carrier Proteins / Q000502:physiology*; D016764:Cell Polarity; D002478:Cells, Cultured; D002923:Cilia / Q000473:pathology* / Q000502:physiology; D007668:Kidney / Q000196:embryology*; D051379:Mice; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000502:physiology*; D012160:Retina / Q000196:embryology*; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins / Q000502:physiology*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; C465818:Ahi1 protein, mouse; C517210:Ahi1 protein, zebrafish; D002352:Carrier Proteins; D011518:Proto-Oncogene Proteins; D029961:Zebrafish Proteins