Detection of an immunoglobulin switch region-specific DNA-binding protein in mitogen-stimulated mouse splenic B cells.
We have detected a nuclear protein from lipopolysaccharide- and dextran sulfate-stimulated mouse splenic B cells which binds specifically to the immunoglobulin switch mu (S mu) sequence. We have termed the binding protein NF-S mu. DNA containing the S mu repeated sequence, GAGCTGGGGTGAGCTGAGCTGAGCT, was used as a probe in electrophoretic mobility shift assays. Methylation interference analysis indicated that binding centers on the run of four guanine residues. Competitions with mutated S mu sequences confirmed the importance of the run of G residues and revealed that optimal binding occurs when they are flanked by GAGCT. The kinetics of the expression of NF-S mu in splenic B cells treated with lipopolysaccharide and dextran sulfate parallels the induction of recombinational activity at S mu in these cells. On the basis of these data, we suggest that NF-S mu may be an effector of switch recombination.
Wuerffel
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RA
Department of Microbiology and Immunology, College of Medicine, University of Illinois, Chicago 60680.
Nathan
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Kenter
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D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism*; D016264:Dextran Sulfate; D003911:Dextrans; D007148:Immunoglobulin mu-Chains / Q000235:genetics*; D008070:Lipopolysaccharides; D008213:Lymphocyte Activation; D008745:Methylation; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D013154:Spleen / Q000276:immunology
D004268:DNA-Binding Proteins; D003911:Dextrans; D007148:Immunoglobulin mu-Chains; D008070:Lipopolysaccharides; D008934:Mitogens; D015345:Oligonucleotide Probes; D016264:Dextran Sulfate