title: Aberrant Wnt signalling and cellular over-proliferation in a novel mouse model of Meckel-Gruber syndrome.
abstract: Meckel-Gruber syndrome (MKS) is an embryonic lethal ciliopathy resulting from mutations in genes encoding proteins localising to the primary cilium. Mutations in the basal body protein MKS1 account for 7% of cases of MKS. The condition affects the development of multiple organs, including brain, kidney and skeleton. Here we present a novel Mks1(tm1a(EUCOMM)Wtsi) knockout mouse which accurately recapitulates the human condition, consistently developing pre-axial polydactyly, complex posterior fossa defects (including the Dandy-Walker malformation), and renal cystic dysplasia. TOPFlash Wnt reporter assays in mouse embryonic fibroblasts (MEFs) showed general de-regulated high levels of canonical Wnt/β-catenin signalling in Mks1(-/-) cells. In addition to these signalling defects, we also observed ectopic high proliferation in the brain and kidney of mutant animals at mid- to late-gestation. The specific role of Mks1 in regulating cell proliferation was confirmed in Mks1 siRNA knockdown experiments which showed increased levels of proliferation after knockdown, an effect not seen after knockdown of other ciliopathy genes. We suggest that this is a result of the de-regulation of multiple signalling pathways (Wnt, mTOR and Hh) in the absence of functional Mks1. This novel model system offers insights into the role of MKS1 in Wnt signalling and proliferation, and the impact of deregulation of these processes on brain and kidney development in MKS, as well as expanding our understanding of the role of Mks1 in multiple signalling pathways.
authors: Section of Ophthalmology and Neurosciences, Leeds Institute of Molecular Medicine, Beckett Street, The University of Leeds, Leeds, LS9 7 TF, UK.
authors: Gabrielle
authors: G
authors: Wheway
authors: Zakia
authors: Z
authors: Abdelhamed
authors: Subaashini
authors: S
authors: Natarajan
authors: Carmel
authors: C
authors: Toomes
authors: Chris
authors: C
authors: Inglehearn
authors: Colin A
authors: CA
authors: Johnson
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D002925:Ciliary Motility Disorders / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D004195:Disease Models, Animal; D004622:Embryo, Mammalian / Q000378:metabolism / Q000473:pathology; D004677:Encephalocele / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D005091:Exons / Q000235:genetics; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005455:Fluorescent Antibody Technique; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D006849:Hydrocephalus / Q000196:embryology / Q000473:pathology; D051379:Mice; D008850:Microphthalmos / Q000196:embryology / Q000473:pathology; D007690:Polycystic Kidney Diseases / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012174:Retinitis Pigmentosa; D060449:Wnt Signaling Pathway
chemical_list: C509166:MKS1 protein, mouse; D011506:Proteins