A role for Ets1, synergizing with AP-1 and GATA-3 in the regulation of IL-5 transcription in mouse Th2 lymphocytes

• Published in: International immunology 2006-02, Vol.18 (2), p.313-323
• Main Authors: Wang, Jun, Shannon, M. Frances, Young, Ian G.
• Format: Article
• Language: English
• Subjects: allergy; Animals; Binding Sites; cAMP cyclic adenosine monophosphate; ChIP chromatin immunoprecipitation; CLE0 conserved lymphokine element 0; Cyclic AMP - pharmacology; cytokines; DNA; DTT dithiothreitol; ERK extracellular signal-related kinase; GATA3 Transcription Factor - physiology; Gene Expression Regulation; gene regulation; Genes, fos; Genes, jun; Genes, Reporter; GFP green fluorescent protein; Interleukin-5 - genetics; JNK c-Jun N-terminal kinase; MAP Kinase Signaling System - physiology; Mice; Molecular Sequence Data; Mutation; PKC protein kinase C; PMA phorbol myristate acetate; Promoter Regions, Genetic; Protein Binding; Proto-Oncogene Protein c-ets-1 - physiology; T lymphocytes; Tetradecanoylphorbol Acetate - pharmacology; Th2 Cells - metabolism; Transcription Factor AP-1 - physiology; Transcription, Genetic; Transcriptional Activation
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/dxh370

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.