title: In vivo characterization of mutant myotilins.
abstract: Myofibrillar myopathy (MFM) is a group of disorders that are pathologically defined by the disorganization of the myofibrillar alignment associated with the intracellular accumulation of Z-disk-associated proteins. MFM is caused by mutations in genes encoding Z-disk-associated proteins, including myotilin. Although a number of MFM mutations have been identified, it has been difficult to elucidate the precise roles of the mutant proteins. Here, we present a useful method for the characterization of mutant proteins associated with MFM. Expression of mutant myotilins in mouse tibialis anterior muscle by in vivo electroporation recapitulated both the pathological changes and the biochemical characteristics observed in patients with myotilinopathy. In mutant myotilin-expressing muscle fibers, myotilin aggregates and is costained with polyubiquitin, and Z-disk-associated proteins and myofibrillar disorganization were commonly seen. In addition, the expressed S60C mutant myotilin protein displayed marked detergent insolubility in electroporated mouse muscle, similar to that observed in human MFM muscle with the same mutation. Thus, in vivo electroporation can be a useful method for evaluating the pathogenicity of mutations identified in MFM.
authors.affiliation: Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Keduka
authors.forename: Yukiko K
authors.initials: YK
authors.lastname: Hayashi
authors.forename: Sherine
authors.initials: S
authors.lastname: Shalaby
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mitsuhashi
authors.forename: Satoru
authors.initials: S
authors.lastname: Noguchi
authors.forename: Ikuya
authors.initials: I
authors.lastname: Nonaka
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D064211:Connectin; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism; D018274:Electroporation / Q000379:methods; D005260:Female; D006801:Humans; D051379:Mice; D008840:Microfilament Proteins; D008854:Microscopy, Electron; D008875:Middle Aged; D009124:Muscle Proteins / Q000235:genetics* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism / Q000648:ultrastructure; D009135:Muscular Diseases / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009154:Mutation; D032446:Myoblasts / Q000378:metabolism; D009210:Myofibrils / Q000378:metabolism; D025821:Polyubiquitin / Q000378:metabolism; D058767:Protein Unfolding
chemical_list: D064211:Connectin; D003598:Cytoskeletal Proteins; C577290:MYOT protein, human; D008840:Microfilament Proteins; D009124:Muscle Proteins; C503771:Myot protein, mouse; D025821:Polyubiquitin