Lamin A/C deficiency is 'unnerving'January 05, 2009Mutations in the nuclear intermediate filament lamin A/C (LMNA) gene are associated with Emery-Dreifuss muscular dystrophy, but cause the disease by unknown mechanisms. Méjat et al. show that one mechanism involves the disruption of neuromuscular junctions. The study will appear online on Monday, January 5, 2009 (www.jcb.org) and in the January 12, 2009 print issue of the Journal of Cell Biology. Muscle fiber cells contain hundreds of nuclei. In normal fibers, several nuclei cluster together under the cell membrane at sites of neuronal contact. These postsynaptic nuclei synthesize the components of the neuromuscular junction that specify the overlying membrane as the target site for innervation. The authors found that LMNA-deficient animals (including those with a point mutation in LMNA that in humans can cause Emery-Dreifuss disease) failed to position nuclei into these postsynaptic clusters. This prevented the proper organization of the neuromuscular junction and disrupted muscle fiber innervation, says author Alexandre Méjat. The authors showed that either loss or mutation of LMNA disrupted nuclear positioning by causing the mislocalization of two other proteins: Nesprin-1, which spans the outer nuclear membrane and anchors nuclei to the actin cytoskeleton, and SUN2, which spans the inner nuclear membrane, linking Nesprin to lamin A/C. Although lamin A/C is ubiquitously expressed, LMNA defects specifically affected striated and skeletal muscle because Nesprin-1 and SUN2 are highly expressed in these tissues. Samples from Emery-Dreifuss muscular dystrophy patients exhibit similar hallmarks of skeletal muscle functional denervation, suggesting the authors are on the right track. Rockefeller University Press |
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| Related Muscular Dystrophy Current Events and Muscular Dystrophy News Articles Treatment to improve degenerating muscle gains strength A study appearing in Science Translational Medicine puts scientists one step closer to clinical trials to test a gene delivery strategy to improve muscle mass and function in patients with certain degenerative muscle disorders. Possible help in fight against muscle-wasting disease A compound already used to treat pneumonia could become a new therapy for an inherited muscular wasting disease, according to researchers at the University of Oregon and the University of Rochester School of Medicine and Dentistry in New York. Exon-skipping drug prevents muscle wasting, maintains muscle function in dystrophin deficient mice An exon skipping PPMO has demonstrated dramatic effects in the prevention and treatment of severely affected, dystrophin and utrophin-deficient mice, preventing severe deterioration of the treated animals and extending their lifespan. To regenerate muscle, cellular garbage men must become builders For scientists at the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy, what seemed like a disappointing result turned out to be an important discovery. Zoo volunteers help explain mysteries of the genome As the University of Leicester approaches the 25th anniversary of the discovery of DNA fingerprinting (September 10), Leicester geneticists interested in a particular type of DNA are receiving some help from an unusual band of assistants. Small molecule inhibits pathology associated with myotonic dystrophy type 1 Researchers at the University of Illinois have designed a small molecule that blocks an aberrant pathway associated with myotonic dystrophy type 1, the most common form of muscular dystrophy. Researchers identify new function for protein missing in Duchenne muscular dystrophy Researchers at the University of Minnesota and National Institutes of Health have identified a new function for the protein missing in people with the most common and ultimately lethal form of childhood muscular dystrophy. Sticky protein helps reinforce fragile muscle membranes A new study by scientists at the University of Iowa shows why muscle membranes don't rupture when healthy people exercise. Stem cell surprise for tissue regeneration Scientists working at the Carnegie Institution's Department of Embryology, with colleagues, have overturned previous research that identified critical genes for making muscle stem cells. Researchers make progress toward early identification of muscular dystrophy The saying "Knowing is half the battle" is never more true than when discussing early treatment of disease. Muscular dystrophy is one such disease where patients can benefit from early treatment. Now, new research is moving doctors and scientists closer to disease diagnosis in advance of patient symptoms. More Muscular Dystrophy Current Events and Muscular Dystrophy News Articles |
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