title: Myopathy phenotype of transgenic mice expressing active site-mutated inactive p94 skeletal muscle-specific calpain, the gene product responsible for limb girdle muscular dystrophy type 2A.
abstract: A defect of the gene for p94 (calpain 3), a skeletal muscle-specific calpain, is responsible for limb girdle muscular dystrophy type 2A (LGMD2A), or 'calpainopathy', which is an autosomal recessive and progressive neuromuscular disorder. To study the relationships between the physiological functions of p94 and the etiology of LGMD2A, we created transgenic mice that express an inactive mutant of p94, in which the active site Cys129 is replaced by Ser (p94:C129S). Three lines of transgenic mice expressing p94:C129S mRNA at various levels showed significantly decreased grip strength. Sections of soleus and extensor digitorum longus (EDL) muscles of the aged transgenic mice showed increased numbers of lobulated and split fibers, respectively, which are often observed in limb girdle muscular dystrophy muscles. Centrally placed nuclei were also frequently found in the EDL muscle of the transgenic mice, whereas wild-type mice of the same age had almost none. There was more p94 protein produced in aged transgenic mice muscles and it showed significantly less autolytic degradation activity than that of wild-type mice. Although no necrotic-regenerative fibers were observed, the age and p94:C129S expression dependence of the phenotypes strongly suggest that accumulation of p94:C129S protein causes these myopathy phenotypes. The p94:C129S transgenic mice could provide us with crucial information on the molecular mech-anism of LGMD2A.
authors.affiliation: Department of Molecular Biology, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan,
authors.forename: K
authors.initials: K
authors.lastname: Tagawa
authors.forename: C
authors.initials: C
authors.lastname: Taya
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: M
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Y
authors.initials: Y
authors.lastname: Ono
authors.forename: R
authors.initials: R
authors.lastname: Fukuda
authors.forename: H
authors.initials: H
authors.lastname: Karasuyama
authors.forename: N
authors.initials: N
authors.lastname: Toyama-Sorimachi
authors.forename: Y
authors.initials: Y
authors.lastname: Katsui
authors.forename: S
authors.initials: S
authors.lastname: Hata
authors.forename: S
authors.initials: S
authors.lastname: Ishiura
authors.forename: I
authors.initials: I
authors.lastname: Nonaka
authors.forename: Y
authors.initials: Y
authors.lastname: Seyama
authors.forename: K
authors.initials: K
authors.lastname: Arahata
authors.forename: H
authors.initials: H
authors.lastname: Yonekawa
authors.forename: H
authors.initials: H
authors.lastname: Sorimachi
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D001835:Body Weight; D002154:Calpain / Q000096:biosynthesis* / Q000235:genetics*; D064211:Connectin; D003545:Cysteine / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D009135:Muscular Diseases / Q000235:genetics*; D009136:Muscular Dystrophies / Q000235:genetics*; D009154:Mutation; D010641:Phenotype; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000378:metabolism; D012694:Serine / Q000378:metabolism
chemical_list: D064211:Connectin; D009124:Muscle Proteins; D012694:Serine; D011494:Protein Kinases; D002154:Calpain; C078134:calpain p94; D003545:Cysteine