The gene responsible for Duchenne muscular dystrophy encodes an mRNA of about 16 kb (kilobases). If the message encodes a single protein, the protein would be about 500 kd in size. The largest known proteins in muscle are nebulin (550 kd) and titin (over 1000 kd). Both proteins have been localized to the junction of the A band (the area of the sarcomere composed of myosin thick filaments) and I band (the area of the sarcomere containing actin thin filaments attached to the Z line). We have examined nondegenerating muscle fibers from five patients with Duchenne muscular dystrophy. A band identified as nebulin from published patterns and molecular weight (approximately 500 kd) was absent or extremely faint in all 30 patients with Duchenne muscular dystrophy. The nebulin band was clear in all controls, and the bands of all other proteins seen in control muscle were equally prominent in muscle from patients with Duchenne muscular dystrophy. Titin was equally prominent in control and Duchenne muscle on immunocytochemistry and sodum dodecyl sulfate-polyacrylamide-gel electrophoresis.
|Number of pages||2|
|Journal||New England Journal of Medicine|
|Publication status||Published - 1987|
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