Intracellular and surface distribution of a membrane protein (CD8) derived from a single nucleus in multinucleated myotubes.
We have investigated the contribution of an individual nucleus to intracellular and surface membranes in multinucleated muscle fibers. Using a retroviral vector, we introduced the gene encoding the human T-lymphocyte antigen CD8 into C2 mouse muscle cells to form a stable line expressing the human protein on its surface. The intracellular and surface distributions of the protein were then investigated by immunocytochemistry in hybrid myotubes containing a single nucleus expressing CD8. We show that the intracellular distribution of CD8 is limited to a local area surrounding the nucleus encoding it and several neighboring nuclei. On the cell surface, however, the protein is distributed over the entire myotube. Widespread distribution of a surface membrane protein in multinucleated myotubes can thus result from localized synthesis and processing.
Ralston
E
E
Department of Physiology, School of Medicine, University of California, San Francisco 94143-0444.
Hall
Z W
ZW
D000818:Animals; D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics; D016827:CD8 Antigens; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002999:Clone Cells; D005796:Genes; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis*; D051379:Mice; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism*; D010957:Plasmids; D012397:Rosette Formation; D014162:Transfection
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D008565:Membrane Proteins