The octamer/mu E4 region of the immunoglobulin heavy-chain enhancer mediates gene repression in myeloma x T-lymphoma hybrids.
We have shown previously that the immunoglobulin heavy-chain enhancer acts as a repressor of gene transcription in hybrids between immunoglobulin-producing myelomas and a T-lymphoma line. We have now mapped this repressive activity to a 51-bp enhancer subfragment which contains the octamer and mu E4 protein-binding motifs. Even a single copy of this subfragment will repress gene expression in hybrid cells. Mutational analyses of the repressor fragment suggest that in non-B cells, a strong transcriptional repressor(s) functions through the same motifs important for gene activation in B cells. Changes in chromatin structure that accompany reporter gene repression suggest a general mechanism for prohibiting immunoglobulin heavy-chain locus activation in inappropriate cell types.
Department of Biological Sciences, Columbia University, New York, New York 10027.
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Shen
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Lieberman
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Eckhardt
D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003850:Deoxyribonuclease I; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D015972:Gene Expression Regulation, Neoplastic; D005803:Genes, Immunoglobulin; D006822:Hybrid Cells; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007148:Immunoglobulin mu-Chains / Q000235:genetics*; D007438:Introns; D016399:Lymphoma, T-Cell / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008969:Molecular Sequence Data; D009101:Multiple Myeloma / Q000235:genetics / Q000276:immunology*; D010430:Pentosyltransferases / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured
D007143:Immunoglobulin Heavy Chains; D007148:Immunoglobulin mu-Chains; D011993:Recombinant Fusion Proteins; D010430:Pentosyltransferases; C024827:xanthine phosphoribosyltransferase; D003850:Deoxyribonuclease I