[Monoclonal antibodies to the muscle isoform of alpha-actinin--a marker for the study of the differentiation of skeletal and cardiac muscles].

A battery of monoclonals to the rabbit skeletal muscle alpha-actinin has been produced. The majority of monoclonals proved to be species-specific by indirect immunofluorescence on the isolated rabbit skeletal myofibrils and on the differentiating cultures of chicken and rat skeletal muscles. One monoclonal, EA-53, reacts with the skeletal muscle alpha-actinin of various species (rat, rabbit, chicken) in immunofluorescence and immunoblotting. The monoclonal EA-53 recognizes also heart muscle alpha-actinin in cultured cardiomyocytes of human, rat and mouse origin. EA-53 does not stain alpha-actinin in myoblasts, fibroblasts, and endothelial cells. The monoclonal antibody EA-53 discriminating muscle and nonmuscle alpha-actinin isoforms could be used as a tool to study the mechanisms of skeletal and cardiac myogenesis.