The immunoglobulin heavy-chain matrix-associating regions are bound by Bright: a B cell-specific trans-activator that describes a new DNA-binding protein family.
B lymphocyte-restricted transcription of immunoglobulin heavy-chain (IgH) genes is specified by elements within the variable region (VH) promoter and the intronic enhancer (E mu). The gene encoding a protein that binds a VH promoter proximal site necessary for induced mu-heavy-chain transcription has been cloned. This B-cell specific protein, termed Bright (B cell regulator of IgH transcription), is found in both soluble and matrix insoluble nuclear fractions. Bright binds the minor groove of a restricted ATC sequence that is sufficient for nuclear matrix association. This sequence motif is present in previously described matrix-associating regions (MARs) proximal to the promoter and flanking E mu. Bright can activate E mu-driven transcription by binding these sites, but only when they occur in their natural context and in cell lines permissive for E mu activity. To bind DNA, Bright requires a novel tetramerization domain and a previously undescribed domain that shares identity with several proteins, including SWI1, a component of the SWI/SNF complex.
Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9048, USA.
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Herrscher
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Kaplan
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Lelsz
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Das
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Scheuermann
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Tucker
D000595:Amino Acid Sequence; D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D018507:Gene Expression Regulation, Developmental; D007143:Immunoglobulin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009857:Oncogenes; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors
C097532:Arid3a protein, mouse; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; D015534:Trans-Activators; D014157:Transcription Factors