A novel 34-kd protein co-isolated with the IgM molecule in surface IgM-expressing cells.
Plasmacytoma cells, transfected with a vector encoding a membrane-bound IgM molecule, do not show cell surface IgM expression, although complete IgM molecules are assembled intracellularly. The isolation of a surface IgM-positive variant allowed us to analyse molecular requirements of surface IgM expression. Only in surface IgM-positive cells, a 34-kd protein (B34) was found to be associated with IgM. B34 is a glycoprotein which forms a disulphide-linked homodimer. The surface IgM-positive variant cell line expressing B34 also contains transcripts of the pre-B and B cell specific mb-1 gene. The data are discussed in the context of a possible IgM-antigen receptor complex.
Hombach
J
J
Institute of Genetics, University of Cologne, FRG.
Leclercq
L
L
Radbruch
A
A
Rajewsky
K
K
Reth
M
M
D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000096:biosynthesis / Q000235:genetics*; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000235:genetics*; D010954:Plasmacytoma; D011947:Receptors, Antigen, B-Cell / Q000096:biosynthesis / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured
D006023:Glycoproteins; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell