Specific regulation of N-CAM/D2-CAM cell adhesion molecule during skeletal muscle development.
The expression of the N-CAM/D2-CAM cell adhesion molecule was studied in skeletal muscle. In cell cultures derived from adult human muscle N-CAM/D2-CAM was found at the cell surface of myoblasts and myotubes but not fibroblasts, showing that N-CAM/D2-CAM is a specific gene product of muscle. Western blots showed that the anti N-CAM/D2-CAM antibody reacted with a single protein band of 180 000 daltons in these cultures that differed in mobility from the broad band of 150 000-200 000 daltons found in brain. N-CAM/D2-CAM is also expressed by muscle at certain stages of development. Human foetal muscle of 10 and 20 weeks gestation showed N-CAM/D2-CAM around developing myofibres while both fast and slow adult muscle fibres did not express N-CAM/D2-CAM, suggesting that the protein is down regulated during myofibre maturation. This was studied further in developing rat muscle where N-CAM/D2-CAM was found on myofibres in the day 1 neonate, but had disappeared by day 9. N-CAM/D2-CAM is, however, re-expressed in human muscle disease where there is muscle regeneration such as in polymyositis, and here is associated with classic regenerating myofibres. N-CAM/D2-CAM expression is temporally regulated and is expressed only at times of synapse formation consistent with the idea that it may be involved in early nerve-muscle interactions.
D000954:Antigens, Surface / Q000235:genetics* / Q000276:immunology; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D005347:Fibroblasts / Q000502:physiology; D005455:Fluorescent Antibody Technique; D005865:Gestational Age; D006801:Humans; D008970:Molecular Weight; D024510:Muscle Development; D009132:Muscles / Q000196:embryology / Q000502:physiology; D009469:Neuromuscular Junction / Q000648:ultrastructure; D012038:Regeneration
D000954:Antigens, Surface; D015815:Cell Adhesion Molecules