title: B lymphocytes contain three species of mu chains.
abstract: The murine B cell line cloned from a single cell, 38C-13, synthesizes three species of mu chains, that of cell surface membrane IgM (m-mu), that of secreted IgM (s-mu) and that of intracellular IgM (i-mu). They differ in their mobility on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Sequence analysis of the different mu chains suggests that they are identical in the N-terminal as well as in their C-terminal positions. The ratio between incorporated radioactive monosaccharides to radioactive amino acids into the three different mu chains was higher in s-mu than in m-mu, but nevertheless m-mu migrated more slowly than s-mu on sodium dodecyl sulfate polyacrylamide gel electrophoresis. However, since this ratio may also be influenced by the rate of synthesis, it may not represent a real molar ratio of carbohydrate to protein. Studies with normal spleen cells clearly indicated the presence of the same three types of mu chains.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D007143:Immunoglobulin Heavy Chains / Q000276:immunology*; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains / Q000276:immunology*; D007136:Immunoglobulins / Q000096:biosynthesis; D007930:Leucine / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D009005:Monosaccharides / Q000378:metabolism; D013154:Spleen / Q000276:immunology
chemical_list: D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007148:Immunoglobulin mu-Chains; D007136:Immunoglobulins; D009005:Monosaccharides; D007930:Leucine