Negative regulation of immunoglobulin kappa light-chain gene transcription by a short sequence homologous to the murine B1 repetitive element.
B-cell-specific expression of the immunoglobulin kappa light-chain (Ig kappa) gene is in part accomplished by negative regulatory influences. Here we describe a new negatively acting element (termed kappa NE) immediately upstream of the NF-kappa B-binding site in the Ig kappa intronic enhancer. The 27-bp kappa NE sequence is conserved in the corresponding positions in the rabbit and human Ig kappa genes, and the human kappa NE homolog was shown to have a similar negative regulatory activity. Data base searches using the mouse kappa NE sequence revealed a striking homology to murine B1 repetitive sequences. A sequence homologous to kappa NE and B1 was also noted in a previously identified silencer element in the murine T-cell receptor alpha locus. The homologous T-cell receptor alpha locus sequence, but notably not a corresponding 27-bp B1 consensus sequence, showed a negative regulatory potential similar to that of kappa NE. The negative effect of kappa NE by itself was not cell type specific but became so when paired with its 5'-flanking sequence in the Ig kappa enhancer. A short (30-bp) fragment upstream of kappa NE (termed kappa BS) was found to be necessary and sufficient for abolishing the negative effect of kappa NE in B cells. Point mutations in a T-rich motif within the kappa BS sequence allowed the transcriptional repression by kappa NE to be evident in B cells as well as other cells. As suggested by this cell-independent negative activity, proteins binding to the mouse and human kappa NE sequences were identified in all cell types tested.
Saksela
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Rockefeller University, New York, New York 10021.
Baltimore
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D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology; D005786:Gene Expression Regulation; D005803:Genes, Immunoglobulin; D005809:Genes, Regulator; D006367:HeLa Cells; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D011817:Rabbits; D011994:Recombinant Proteins / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014162:Transfection
D007145:Immunoglobulin kappa-Chains; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D008156:Luciferases