Myofibrillar M-line structure in normal and dystrophic hamster muscle.

The presence of the specific myofibrillar M-line marker, myomesin , in isolated myofibrils and cryosections of skeletal and heart muscle as well as its appearance during differentiation in skeletal and heart muscle cell cultures of normal and dystrophic hamsters were evaluated. By means of the indirect immunofluorescence technique employing antibodies against chicken M-line proteins, the appearance of antigen localized in the M-line was investigated. No difference could be found between the M-line structure of normal and dystrophic animals. The results suggest that the M-line proteins, apparently relatively stable, are not primarily affected by the disease.