Immunoelectronmicroscopic localization of alpha-actinin in skeletal muscle cells

The ultrastructural distribution of alpha-actinin in skeletal myocytes was studied by a sensitive method that permits localization of antigenic proteins in intact fixed cells rather than in glycerol estracted tissues or isolated cell fractions. Binding to the Z line of specific antiserum produced in rabbits immunized with highly purified alpha-actinin was demonstrated by deposition at this site of a reaction product of horseradish peroxidase that had been coupled to antigen-binding fragments of sheep anti-rabbit gamma globulin.