title: Interleukin-21 receptor gene induction in human T cells is mediated by T-cell receptor-induced Sp1 activity.
abstract: Interleukin-21 (IL-21) plays important roles in regulating the immune response. IL-21 receptor (IL-21R) mRNA is expressed at a low level in human resting T cells but is rapidly induced by mitogenic stimulation. We now investigate the basis for IL21R gene regulation in T cells. We found that the -80 to -20 region critically regulates IL-21R promoter activity and corresponds to a major DNase I-hypersensitive site. Electrophoretic mobility shift assays, DNA affinity chromatography followed by mass spectrometry, and chromatin immunoprecipitation assays revealed that Sp1 binds to this region in vitro and in vivo. Moreover, mutation of the Sp1 motif markedly reduced IL-21R promoter activity, and Sp1 small interfering RNAs effectively diminished IL-21R expression in activated T cells. Interestingly, upon T-cell receptor (TCR) stimulation, T cells increased IL-21R expression and Sp1 protein levels while decreasing Sp1 phosphorylation. Moreover, phosphatase inhibitors that increased phosphorylation of Sp1 diminished IL-21R transcription. These data indicate that TCR-induced IL-21R expression is driven by TCR-mediated augmentation of Sp1 protein levels and may partly depend on the dephosphorylation of Sp1.
authors.affiliation: Laboratory of Molecular Immunology, National Heart, Lung, and Blood InstituteNational Institutes of Health, Building 10, Room 7N252, Bethesda, Maryland 20892-1674, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wu
authors.forename: Hyoung-Pyo
authors.initials: HP
authors.lastname: Kim
authors.forename: Hai-Hui
authors.initials: HH
authors.lastname: Xue
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.forename: Keji
authors.initials: K
authors.lastname: Zhao
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Leonard
mesh_terms: D020816:Amino Acid Motifs; D001483:Base Sequence; D015153:Blotting, Western; D047369:Chromatin Immunoprecipitation; D002846:Chromatography, Affinity; D004262:DNA Restriction Enzymes / Q000494:pharmacology; D003850:Deoxyribonuclease I / Q000378:metabolism; D005091:Exons; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006801:Humans; D053738:Interleukin-21 Receptor alpha Subunit; D008156:Luciferases / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism; D013058:Mass Spectrometry; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D018123:Receptors, Interleukin / Q000235:genetics*; D053655:Receptors, Interleukin-21; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016329:Sp1 Transcription Factor / Q000378:metabolism; D051705:Sp3 Transcription Factor / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
chemical_list: C508117:IL21R protein, human; D053738:Interleukin-21 Receptor alpha Subunit; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011948:Receptors, Antigen, T-Cell; D018123:Receptors, Interleukin; D053655:Receptors, Interleukin-21; D016329:Sp1 Transcription Factor; D051705:Sp3 Transcription Factor; D008156:Luciferases; D004262:DNA Restriction Enzymes; D003850:Deoxyribonuclease I