title: B-cell nuclear proteins binding in vitro to the human immunoglobulin kappa enhancer: localization by exonuclease protection.
abstract: Proteins capable of interacting with the enhancer of the immunoglobulin kappa gene in vitro have been detected in extracts of nuclei from human B cells and from human, mouse, and rabbit spleens. The experiments, based on an exonuclease protection technique, demonstrate nuclear protein factors binding to a 30- to 35-base-pair domain containing both the simian virus 40 enhancer core element (TTTCCA) and the octamer CAGGTGGC that was previously identified as the consensus sequence for protein-binding sites in the murine immunoglobulin heavy-chain enhancer. This 30- to 35-base-pair domain in the human kappa enhancer is homologous to a site of protein binding detected in the murine kappa enhancer by other investigators using a gel retardation assay. Our results complement in vivo dimethyl sulfate footprinting studies of the human immunoglobulin kappa enhancer which demonstrated B cell-specific changes in guanine reactivity immediately 5' to the consensus octamer. Together, these findings suggest that DNA-binding proteins in B-cell nuclei interact with the 5' portion of the human kappa-gene enhancer. Such proteins could play a role in the B cell-specific transcription of the human immunoglobulin kappa gene.
mesh_terms: D001402:B-Lymphocytes / Q000502:physiology*; D001665:Binding Sites; D002467:Cell Nucleus / Q000502:physiology; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005092:Exonucleases; D005786:Gene Expression Regulation; D005809:Genes, Regulator; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D066298:In Vitro Techniques; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D007145:Immunoglobulin kappa-Chains; D014157:Transcription Factors; D005092:Exonucleases