title: Positive and negative regulation of IL-2 gene expression: role of multiple regulatory sites.
abstract: Interleukin 2 (IL-2) is an important lymphokine required in the process of T cell activation, proliferation, clonal expansion and differentiation. The IL-2 gene displays both T cell specific and inducible expression: it is only expressed in CD4+ T cells after antigenic or mitogenic stimulation. Several cis-acting regulatory sites are required for induction of the IL-2 gene after stimulation. In this study, we have analysed the function of these cis-acting regulatory sites in the context of the native IL-2 enhancer and promoter sequence. The results of this study suggest that the NFAT (-276 to -261), the distal octamer (-256 to -248) and the proximal octamer (-75 to -66) sites not only act as enhancers of IL-2 gene transcription in the presence of cellular stimulation, but also have a silencing effect on IL-2 gene expression in resting cells. Two other sites display disparate effects on IL-2 gene expression in different T leukemia cell lines: the distal purine box (-291 to -277) and the proximal purine box sites (-145 to -128). Finally, the AP-1 (-186 to -176) and the kappa B sites (-206 to -195) respond to different cellular activation in EL4 cells. The AP-1 site mediated the response to PMA stimulation while the kappa B site responded to IL-1 stimulation. These data suggest that the regulation of IL-2 gene expression is a complex process and multiple cis-acting regulatory sites interact to exert different effects in T cells representative of alternative stages of differentiation.
authors.affiliation: Howard Hughes Medical Institute, University of Michigan Medical Center, Department of Internal Medicine, Ann Arbor 48109-0650.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: G J
authors.initials: GJ
authors.lastname: Nabel
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D004742:Enhancer Elements, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000235:genetics; D015759:Ionomycin / Q000494:pharmacology; D015458:Leukemia, T-Cell; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D011687:Purines; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D016385:TATA Box; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D007375:Interleukin-1; D007376:Interleukin-2; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D016755:Proto-Oncogene Proteins c-jun; D011687:Purines; D014157:Transcription Factors; D015759:Ionomycin; D015500:Chloramphenicol O-Acetyltransferase