Utrophin Localization in Normal and Dystrophin‐Deficient Heart

The localization of dystrophin at the sarcolemma of cardiac skeletal fibers and cardiac Purkinje fibers has been described. Dystrophin deficiency produces clinical manifestations of disease in skeletal muscles and hearts of patients with Duchenne and Becker muscular dystrophy. Utrophin (or dystrophin-related protein), a dystrophin homologous protein, was found to be expressed in fetal muscles and reexpressed in dystrophin-deficient skeletal muscle fibers. We therefore examined utrophin expression in normal and in dystrophindeficient hearts. Methods and ResultsThe expression and subcellular distribution of utrophin was examined in cardiac muscle by immunoblot and immunofluorescence analysis in normal bovine heart compared with dystrophin. Utrophin expression was also examined in normal and dystrophin-deficient hearts of MDX mice. Three monoclonal antibodies reacting with dystrophin and utrophin solely or reacting with both proteins along with two polyclonal antibodies reacting with either utrophin or dystrophin and utrophin were tested. In normal bovine heart, utrophin was not expressed at the periphery of fibers but was strongly expressed in intercalated disks and in the cytoplasm of cardiac Purkinje fibers. In cardiocytes, utrophin was colocalized along transverse T tubules with dystrophin. Dystrophin was present at the periphery of cardiocytes and cardiac Purkinje fibers as well as in transverse T tubules but was absent or faintly expressed in intercalated disks. The results with monoclonal and polyclonal antibodies were identical. Western blot analysis revealed that the detected molecules corresponded only to a 400-kD protein band and not to possible shorter transcripts of utrophin or dystrophin (apo-utrophin or apo-dystrophin). In dystrophin-deficient hearts of MDX mice, utrophin alone was abundant but not organized in the same networklike distribution. ConclusionsThis first localization of utrophin in normal heart (in Purkinje fibers, transverse tubules, and intercalated disks) showed a distinct subcellular localization of this protein with dystrophin, suggesting an important function of this protein in intercellular communication. In dystrophin-deficient hearts of MDX mice, utrophin alone is overexpressed as in skeletal muscle sarcolemma, an area normally occupied by dystrophin but not organized in the same networklike distribution.

[1]  J. Léger,et al.  Dystrophin and dystrophin-related protein (utrophin) distribution in normal and dystrophin-deficient skeletal muscles , 1993, Neuromuscular Disorders.

[2]  J. Léger,et al.  Monoclonal antibodies targeted against the C‐terminal domain of dystrophin or utrophin , 1993, FEBS letters.

[3]  K. Campbell,et al.  Restoration of dystrophin‐associated proteins in skeletal muscle of mdx mice transgenic for dystrophin gene , 1993, FEBS letters.

[4]  P. Kitabgi,et al.  Immunological and biochemical characterization of processing products from the neurotensin/neuromedin N precursor in the rat medullary thyroid carcinoma 6-23 cell line. , 1993, The Biochemical journal.

[5]  P. Kitabgi,et al.  Biosynthesis and posttranslational processing of the neurotensin/neuromedin N precursor in the rat medullary thyroid carcinoma 6-23 cell line. Effect of dexamethasone. , 1993, Endocrinology.

[6]  K. Davies,et al.  Localization and Quantitation of the Chromosome 6-Encoded Dystrophin-Related Protein in Normal and Pathological Human Muscle , 1993, Journal of neuropathology and experimental neurology.

[7]  J. Ervasti,et al.  Dystrophin-glycoprotein complex and laminin colocalize to the sarcolemma and transverse tubules of cardiac muscle. , 1993, Circulation research.

[8]  K. Davies,et al.  Primary structure of dystrophin-related protein , 1992, Nature.

[9]  J. Ervasti,et al.  Association of dystrophin-related protein with dystrophin-associated proteins in mdx mouse muscle , 1992, Nature.

[10]  C. Young,et al.  Different distributions of dystrophin and related proteins at nerve-muscle junctions. , 1992, Neuroreport.

[11]  C. Caskey,et al.  Expression and Localization of Dystrophin in Human Cardiac Purkinje Fibers , 1992, Circulation.

[12]  K. Davies,et al.  Characterization of a 4.8kb transcript from the Duchenne muscular dystrophy locus expressed in Schwannoma cells. , 1992, Human molecular genetics.

[13]  C. Caskey,et al.  Human and murine dystrophin mRNA transcripts are differentially expressed during skeletal muscle, heart, and brain development. , 1992, Nucleic acids research.

[14]  J. Léger,et al.  A homologue of dystrophin is expressed at the blood vessel membrane of DMD and BMD patients: Immunological evidence , 1992, Journal of the Neurological Sciences.

[15]  M. Takemitsu,et al.  Dystrophin-related protein in the fetal and denervated skeletal muscles of normal and mdx mice. , 1991, Biochemical and biophysical research communications.

[16]  J. Léger,et al.  Xp21 dystrophin and 6q dystrophin-related protein. Comparative immunolocalization using multiple antibodies. , 1991, The American journal of pathology.

[17]  J. Léger,et al.  A homologue of dystrophin is expressed at the neuromuscular junctions of normal individuals and DMD patients, and of normal and mdx mice Immunological evidence , 1991, FEBS letters.

[18]  W. Denetclaw,et al.  Increased activity of calcium leak channels in myotubes of Duchenne human and mdx mouse origin. , 1990, Science.

[19]  R. Heilig,et al.  Isolated dystrophin molecules as seen by electron microscopy. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[20]  J. Ervasti,et al.  Deficiency of a glycoprotein component of the dystrophin complex in dystrophic muscle , 1990, Nature.

[21]  J. Lansman,et al.  Calcium entry through stretch-inactivated ion channels in mdx myotubes , 1990, Nature.

[22]  J. Bockaert,et al.  Neuroblastoma Differentiation Involves the Expression of Two Isoforms of the α‐Subunit of Go , 1990 .

[23]  B. Cooper,et al.  Development of Duchenne-type cardiomyopathy. Morphologic studies in a canine model. , 1989, The American journal of pathology.

[24]  D. Branton,et al.  Sequence similarity of the amino-terminal domain of Drosophila beta spectrin to alpha actinin and dystrophin , 1989, The Journal of cell biology.

[25]  R. Heilig,et al.  The chicken dystrophin cDNA: striking conservation of the C‐terminal coding and 3′ untranslated regions between man and chicken. , 1988, The EMBO journal.

[26]  P. Blache,et al.  Development of an oxyntomodulin/glicentin C-terminal radioimmunoassay using a "thiol-maleoyl" coupling method for preparing the immunogen. , 1988, Analytical biochemistry.

[27]  Hideo Sugita,et al.  Immunostaining of skeletal and cardiac muscle surface membrane with antibody against Duchenne muscular dystrophy peptide , 1988, Nature.

[28]  T. Partridge,et al.  THE mdx MOUSE SKELETAL MUSCLE MYOPATHY: I. A HISTOLOGICAL, MORPHOMETRIC AND BIOCHEMICAL INVESTIGATION , 1988, Neuropathology and applied neurobiology.

[29]  Eric P. Hoffman,et al.  Dystrophin: The protein product of the duchenne muscular dystrophy locus , 1987, Cell.

[30]  M. Koenig,et al.  Complete cloning of the duchenne muscular dystrophy (DMD) cDNA and preliminary genomic organization of the DMD gene in normal and affected individuals , 1987, Cell.

[31]  L. Bridges.  The association of cardiac muscle necrosis and inflammation with the degenerative and persistent myopathy of MDX mice , 1986, Journal of the Neurological Sciences.

[32]  J. Léger,et al.  Local diversity of myosin expression in mammalian atrial muscles. Variations depending on age and thyroid state in the rat and the rabbit. , 1985, Circulation research.

[33]  D. Doyle,et al.  Pathogenesis of Human Muscular Dystrophies , 1978 .

[34]  J. Perloff,et al.  The Cardiomyopathy of Progressive Muscular Dystrophy , 1966, Circulation.