Regulation of antibody class switching to IgE: characterization of an IL-4-responsive region in the immunoglobulin heavy-chain germline epsilon promoter
Department of Molecular Genetics and Microbiology
Animals; Base Sequence; Binding Sites; DNA-Binding Proteins; Gene Expression Regulation; *Genes, Immunoglobulin; Genes, Reporter; Humans; *Immunoglobulin Class Switching; Immunoglobulin Constant Regions; Immunoglobulin E; Immunoglobulin Heavy Chains; Interleukin-4; Luciferases; Mice; Molecular Sequence Data; Mutagenesis, Site-Directed; *Promoter Regions (Genetics); Sequence Alignment; Sequence Homology, Nucleic Acid; Transcription Factors
Life Sciences | Medicine and Health Sciences | Women's Studies
A large body of data indicate that antibody class switching is directed by cytokines by inducing or repressing transcription from unrearranged, or germline, CH genes. IL-4 induces transcription of the germline C epsilon genes in activated B cells, and subsequently cells in this population will undergo switch recombination to IgE. Furthermore, the data suggest that transcription of germline C epsilon genes is required for class switching. In this paper we define DNA elements required for induction of transcription of the germline C epsilon genes by IL-4. To do this, segments of DNA from the 5' flank of the initiation sites for germline epsilon RNA were ligated to a luciferase reporter gene and transfected into two mouse B-cell lines, one of which can be induced to switch to IgE. By analysis of a series of 5' deletion constructs and linker-scanning mutations, we demonstrate that a 46-bp segment (residing at -126/-79 relative to the first RNA initiation site) contains an IL-4 responsive region. This segment binds three transcription factors: the recently described NF-IL4, one or more members of the C/EBP family of transcription factors, and NF-kappa B/p50. Mutation of any of the binding sites for these three factors abolishes or reduces IL-4 inducibility of the epsilon promoter. A 27-bp segment within this IL-4 response region containing binding sites for NF-IL4 and a C/EBP factor is sufficient to transfer IL-4 inducibility to a minimal c-fos promoter.
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Citation: Ann N Y Acad Sci. 1995 Sep 29;764:123-35.
Delphin, S. and Stavnezer, Janet, "Regulation of antibody class switching to IgE: characterization of an IL-4-responsive region in the immunoglobulin heavy-chain germline epsilon promoter" (1995). Women’s Health Research Faculty Publications. 208.