International Immunology Advance Access originally published online on July 6, 2005
International Immunology 2005 17(8):973-982; doi:10.1093/intimm/dxh280
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A negative regulatory element in the rabbit 3'IgH chromosomal region
Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA
1 Present address: Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
Correspondence to: K. L. Knight; E-mail: kknight{at}lumc.edu
Mouse and human IgH loci contain several 3'IgH enhancers. In rabbit, a single hs1,2 enhancer is located 3' of the distal germ line C
gene, C
13. We searched for additional regulatory elements in this region by using a luciferase reporter assay and nucleotide sequence analysis. Within 8 kb 3' of C
13, we identified a 1-kb fragment that negatively regulated the hs1,2 enhancement of the I
promoter. This negative regulatory element, C
-NRE, contains a conserved 300-bp region that is associated with 8 of the 13 germ line C
genes. This conserved region contains an E box that, by electrophoretic mobility shift assay, binds an E47-like protein. At the 5' end, C
-NRE also includes a 270-bp region with 20-bp repeats nearly identical to those 3' of mouse and human C
genes, and these repeats bind unidentified nuclear protein(s). C
-NRE appears to be a novel regulatory element that may contribute to the regulation of IgH gene expression.
Keywords: B cells, gene regulation, molecular biology, rabbit, transcription factors