Identification of a conserved lipopolysaccharide-plus-interleukin-4-responsive element located at the promoter of germ line epsilon transcripts.
Treatment of splenic B lymphocytes and certain B-lineage cell lines with the mitogen lipopolysaccharide (LPS) and the lymphokine interleukin-4 (IL-4) induces expression of germ line immunoglobulin C epsilon transcripts and class switching to the C epsilon gene. We show that LPS-plus-IL-4 induction of germ line epsilon transcripts (termed I epsilon transcripts) occurs at the transcriptional level in an Abelson murine leukemia virus-transformed pre-B-cell line. A 1.1-kb region of DNA surrounding the I epsilon promoter endows inducible transcription to a heterologous reporter gene stably transfected into these cells; such inducible expression depends on combined treatment with LPS and IL-4. Analyses of constructs transiently introduced into a B-cell lymphoma line demonstrated that LPS-plus-IL-4-inducible expression can be conferred by a 179-bp segment of DNA spanning the I epsilon transcriptional initiation site. Mutational analyses demonstrated that this expression depended on DNA sequences within a conserved region directly upstream from the I epsilon transcriptional initiation region. One nuclear protein that is constitutively expressed in normal B cells binds to the downstream end of the conserved sequence; its binding specificity correlates with the functional effect of several mutations. Two additional proteins, which are induced by IL-4 treatment of splenic B cells, bind to the transcription initiation sites of I epsilon. These proteins are indistinguishable in binding assays from proteins previously shown to bind an enhancer region of the class II major histocompatibility complex gene A alpha.
Howard Hughes Medical Institute, Columbia University College of Physicians and Surgeons, New York, New York 10032.
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Rothman
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Li
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Gorham
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Glimcher
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Alt
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Boothby
D000011:Abelson murine leukemia virus / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002461:Cell Line, Transformed; D007127:Immunoglobulin Constant Regions / Q000235:genetics; D007134:Immunoglobulin Switch Region / Q000187:drug effects*; D007139:Immunoglobulin epsilon-Chains / Q000235:genetics*; D015847:Interleukin-4 / Q000494:pharmacology*; D008070:Lipopolysaccharides; D016393:Lymphoma, B-Cell; D051379:Mice; D008969:Molecular Sequence Data; D009841:Oligonucleotides; D011401:Promoter Regions, Genetic / Q000187:drug effects; D014158:Transcription, Genetic; D014162:Transfection
D007127:Immunoglobulin Constant Regions; D007139:Immunoglobulin epsilon-Chains; D008070:Lipopolysaccharides; D009841:Oligonucleotides; D015847:Interleukin-4