Ultrastructural localization of the C-terminus of the 43-kd dystrophin-associated glycoprotein and its relation to dystrophin in normal murine skeletal myofiber.
We used single and double immunogold labeling electron microscopy to investigate ultrastructural localization of the C terminus of the 43-kd dystrophin-associated glycoprotein (43-DAG) and its relationship to dystrophin in normal murine skeletal myofibers. Single immunolabeling localized the antibody against the C terminus of 43-DAG to the inside surface of the muscle plasma membrane and the sarcoplasmic side of plasma membrane invaginations. Double immunolabeling co-localized antibodies against dystrophin and the C terminus of 43-DAG to the same site noted in the single immunolabeling localization of 43-DAG. In particular, dystrophin and the C-terminal 43-DAG antibody signals were often observed as doublets separated by less than 30 nm. We compared these results with those obtained from double immunogold labeling with anti-dystrophin and anti-beta-spectrin, as well as anti-C-terminal 43-DAG and anti-beta-spectrin antibodies. The antibodies against dystrophin and beta-spectrin, or beta-spectrin and 43-DAG, also co-localized to similar sites in skeletal muscle fibers. Signals of doublet formations were noted but their frequency was significantly lower than the doublet frequency of antidystrophin and anti-43-DAG antibodies. The results support the presence of dystrophin and 43-DAG linkage at the inside surface of the murine skeletal muscle plasma membrane.
Department of Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan.
Y
Y
Wakayama
S
S
Shibuya
A
A
Takeda
T
T
Jimi
Y
Y
Nakamura
H
H
Oniki
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000648:ultrastructure*; D049030:Dystroglycans; D016189:Dystrophin / Q000032:analysis / Q000648:ultrastructure*; D008562:Membrane Glycoproteins / Q000032:analysis / Q000648:ultrastructure*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D018485:Muscle Fibers, Skeletal / Q000737:chemistry* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000276:immunology
D003598:Cytoskeletal Proteins; D016189:Dystrophin; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D049030:Dystroglycans