Muscle repair protein

Muscular dystrophies represent a heterogeneous group of disorders characterized by wasting and weakness of skeletal muscle. A novel mammalian gene, dysferlin — predicted to encode a product related to Caenorhabditis elegans spermatogenesis factor fer-1 — is mutated in limb-girdle muscular dystrophy type 2B and in Miyoshi myopathy, but the molecular mechanisms that lead to muscle degeneration in these conditions have been unclear. In the May 8 Nature, Dimple Bansal and colleagues from University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, show that disruption of the muscle membrane repair machinery is responsible for dysferlin-deficient muscle degeneration (Nature, 423:168-172, May 8, 2003).

Bansal et al. generated dysferlin-null mice by homologous recombination. They observed that these mice had a functional dystrophin–glycoprotein complex but developed a progressive muscular dystrophy with sub-sarcolemmal accumulations of vesicles that occurred in response to sarcolemma injuries. In addition, membrane repair assays...