The importance of the 3'-enhancer region in immunoglobulin kappa gene expression.
The first enhancers to be identified in the immunoglobulin gene loci are located in the J-C intron. However, deletion of the immunoglobulin kappa intron-enhancer has little effect on the transcription of kappa transgenes. Here we ask whether the second kappa enhancer which we recently identified at the 3'-end of the locus plays a role in kappa gene expression. We show that its omission leads to 20-40 fold lower expression of kappa transgenes and to poor allelic exclusion. Transfection experiments show that activity of the 3'-enhancer, like that of the kappa-intron enhancer, can be induced in a pre-B cell line by incubation with bacterial lipopolysaccharide. Whereas induction of the kappa-intron enhancer is due to induction of NF-kappa B activity, deletion mapping of the 3'-enhancer localises its activity to a 50 nucleotide region that lacks an NF-kappa B site; indeed the 3'-enhancer allows kappa expression in a cell line which lacks NF-kappa B. Thus, both the 3'- and intron-enhancers can be induced at the same stage of differentiation but by distinct pathways. Furthermore, unlike the intron-enhancer, the 3'-enhancer plays a critical role in the transcription of rearranged immunoglobulin kappa genes.
Meyer
K B
KB
MRC Laboratory of Molecular Biology, Cambridge, UK.
Sharpe
M J
MJ
Surani
M A
MA
Neuberger
M S
MS
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D015321:Gene Rearrangement; D005803:Genes, Immunoglobulin; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007438:Introns; D008070:Lipopolysaccharides / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D010954:Plasmacytoma; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
D007145:Immunoglobulin kappa-Chains; D008070:Lipopolysaccharides; D016328:NF-kappa B