Immunogold labelling of dystrophin in human muscle, using an antibody to the last 17 amino acids of the C-terminus

Abstract Immunolabelling with a 10 nm gold probe was used to localize dystrophin at the ultrastructural level in human skeletal muscle. The primary antibody was raised against a synthetic peptide containing the last 17 amino acids at the C-terminus of dystrophin. Using this antibody, labelling was almost entirely confined to a narrow band enclosing 40 nm either side of the plasma membrane and including the membrane itself. Histograms of the position of the gold probe relative to the plasma membrane showed modes lying over the membrane itself or the extracellular face of the membrane. One interpretation of these results is that the C-terminus of dystrophin is inserted in the plasma membrane alongside the glycoproteins with which it is tightly associated. Histograms of the distances between gold probes displayed modes at approximately 120 nm in both transverse and longitudinal sections suggesting that dystrophin forms a lattice-like network adjacent to the plasma membrane.