Characterising a novel mouse model with a mutated ciliopathy gene ( Cep290 ) leading to Joubert Syndrome

摘要

Joubert syndrome (JBTS) is an inherited ciliopathy leadingto a cerebellum-retinal-renal syndrome. Recent geneticadvances have allowed positional cloning and identificationof numerous JBTS genes. CEP290, one of the JBTSgenes identified, (alias NPHP6) encodes a centrosomalprotein and accounts for 7% of patients with Joubert syndrome.We have identified a murine Embryonic Stem (ES)cell line containing a Cep290 “gene trap” using data basesearches. ES cells were cultured before injecting into murineblastocysts to create chimaeric mice. Chimeras werebred to produce viable, healthy heterozygous mutant mice.Heterozygous mutant mice have been intercrossed to producemice homozygous for the Cep290 truncating mutation.Cep290-/- animals (homozygous for the gene trapCep290) exhibit a cortico-medullary cystic kidney diseasecommencing from birth. Histological examination revealsthat these cysts are collecting duct in origin, staining positivelyfor aquaporin-2 and -3. In this study the cilia wereinvestigated in cystic Cep290-/- animals using ElectronMicroscopy (EM) analysis. Scanning electron microscopy(SEM) identified that cilia were evident within renaltubules in Cep290-/- animals. Once cilia were identified inCep290-/- animals Transmission Electron Microscopy(TEM) was carried out to investigate cross sections of thecollecting duct cilium in cystic and non-cystic kidneys.TEM analysis identified tubular basement membrane disruptionsin Cep290-/- animals. The Cep290-/- mousedescribed provides an excellent model to investigate themechanisms involved in cyst formation and to test noveltherapeutic agents.