A role for Ets1, synergizing with AP-1 and GATA-3 in the regulation of IL-5 transcription in mouse Th2 lymphocytes.
IL-5 is a key regulator of eosinophilic inflammation and is selectively expressed by antigen-activated Th2 lymphocytes. An important role for the proximal AP-1 and GATA sites in regulating IL-5 transcription is generally accepted but the significance of an adjacent Ets/NFAT site has remained unclear. We have investigated its role using the mouse Th2 clone D10.G4.1. Transcription of IL-5 reporter gene plasmids could be induced in D10 cells by phorbol myristate acetate/cyclic adenosine monophosphate (PMA/cAMP) stimulation and significantly further enhanced by activation of the mitogen-activated protein (MAP) kinase pathways. Strong induction of IL-5 mRNA was also induced by PMA/cAMP. Mutagenesis showed that the Ets/NFAT site is of critical importance along with the AP-1 and GATA sites in regulating IL-5 transcription stimulated by PMA/cAMP and MAP kinase activation. Transactivation was used to investigate the transcription factors which could function at the three sites and possible synergistic interactions. AP-1 (c-Fos/c-Jun) strongly induced IL-5 transcription and dominant negative AP-1 constructs confirmed that AP-1 plays an important role in regulating IL-5 expression. Ets1, unlike other members of the Ets/NFAT family, synergized strongly with AP-1 suggesting that Ets1 is the family member which functions at the Ets/NFAT site. AP-1/Ets1 transactivation also stimulated IL-5 mRNA expression. Ets1 binding to the proximal promoter region, demonstrated by chromatin immunoprecipitation, was stimulated by PMA/cAMP. The absolute dependence on the binding sites for Ets1, AP-1 and GATA-3 together with the strong synergy between Ets1 and AP-1 suggest close cooperative interactions between the three transcription factors in the regulation of IL-5 expression in mouse T cells.
Wang
Jun
J
Division of Molecular Bioscience, John Curtin School of Medical Research, Australian National University, Mills Road, Acton, ACT 0200 Australia.
Shannon
M Frances
MF
Young
Ian G
IG
D000818:Animals; D001665:Binding Sites; D000242:Cyclic AMP / Q000494:pharmacology; D004247:DNA; D050990:GATA3 Transcription Factor / Q000502:physiology*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D016762:Genes, fos; D016758:Genes, jun; D015848:Interleukin-5 / Q000235:genetics*; D020935:MAP Kinase Signaling System / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D050784:Proto-Oncogene Protein c-ets-1 / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018418:Th2 Cells / Q000378:metabolism*; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D050990:GATA3 Transcription Factor; D015848:Interleukin-5; D050784:Proto-Oncogene Protein c-ets-1; D018808:Transcription Factor AP-1; D004247:DNA; D000242:Cyclic AMP; D013755:Tetradecanoylphorbol Acetate