title: Dystrophin and a dystrophin-related protein in intrafusal muscle fibers, and neuromuscular and myotendinous junctions.
abstract: To determine whether or not and how dystrophin exists in neuromuscular junctions (NMJs) and myotendinous junctions (MTJs), we studied the mid-belly and peripheral portions of control and mdx muscles, immunohistochemically and immunoelectrophoretically, using six kinds of polyclonal antibodies, and an antibody against a dystrophin-related protein (DRP). In controls these regions and the polar region of intrafusal muscle fibers showed a rather clearer immunohistochemical dystrophin reaction than those of extrafusal muscle fibers with all antibodies used. In the muscles of mdx mice NMJs only showed a positive dystrophin reaction with the c-terminal antibody, that is, no reaction with the other five antibodies, and MTJs in mdx showed a positive reaction with the c-terminal antibody and a faint to negative reaction with the other five antibodies. In biopsied human muscles NMJs and MTJs also showed a clear reaction with all ten antibodies, i.e., six polyclonal and four monoclonal ones. Although an immunohistochemical DRP reaction was clearly seen at NMJs, only a faint or no reaction was seen on MTJs and on intrafusal muscle fibers in both mouse and human materials. Western blot analysis of control mouse muscle for dystrophin showed a clearer band for the peripheral portion, which contains many MTJs, than for the mid-belly portion. These data suggest that dystrophin really exists on MTJs, and that dystrophin and DRP exist on NMJs in mouse and human muscles.
authors.affiliation: Department of Child Development, Kumamoto University Medical School, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: K
authors.initials: K
authors.lastname: Yoshioka
authors.forename: M
authors.initials: M
authors.lastname: Miyatake
authors.forename: T
authors.initials: T
authors.lastname: Miike
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D016189:Dystrophin / Q000378:metabolism*; D007122:Immunoelectrophoresis; D007150:Immunohistochemistry; D008565:Membrane Proteins; D051379:Mice; D008818:Mice, Neurologic Mutants; D009132:Muscles / Q000378:metabolism* / Q000648:ultrastructure; D009469:Neuromuscular Junction / Q000378:metabolism* / Q000648:ultrastructure; D013710:Tendons / Q000378:metabolism* / Q000648:ultrastructure; D049411:Utrophin
chemical_list: D000911:Antibodies, Monoclonal; D003598:Cytoskeletal Proteins; D016189:Dystrophin; D008565:Membrane Proteins; C483600:Utrn protein, mouse; D049411:Utrophin