Enhancer role of STAT5 in CD2 activation of IFN-gamma gene expression

J Immunol. 2004 Nov 15;173(10):6241-7. doi: 10.4049/jimmunol.173.10.6241.

Abstract

IFN-gamma is an important immunoregulatory protein with tightly controlled expression in activated T and NK cells. Three potential STAT binding regions have been recognized within the IFN-gamma promoter: 1) an IL-12-mediated STAT4 binding site at -236 bp; 2) a newly identified IL-2-induced STAT5 binding element at -3.6 kb; and 3) CD2-mediated STAT1 and STAT4 binding to an intronic element in mucosal T cells. However, functional activation of these sites remains unclear. In this study we demonstrate CD2-mediated activation of the newly characterized -3.6-kb IFN-gamma STAT5 binding region. CD2 signaling of human PBMC results in activation of the -3.6-kb IFN-gamma promoter, whereas mutation of the -3.6-kb STAT5 site attenuates promoter activity. Functional activation is accompanied by STAT5A but little STAT5B nucleoprotein binding to the IFN-gamma STAT5 site, as determined by competition and supershift assays. STAT5 activation via CD2 occurs independent of IL-2. Western and FACS analysis shows increased phospho-STAT5 following CD2 signaling. AG490, a tyrosine kinase inhibitor affecting Jak proteins, inhibits CD2-mediated IFN-gamma mRNA expression, secretion, and nucleoprotein binding to the IFN-gamma STAT5 site in a dose-dependent fashion. This report is the first to describe CD2-mediated activation of STAT5 and supports STAT5 involvement in regulation of IFN-gamma expression.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • CD2 Antigens / physiology*
  • Cells, Cultured
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • Enhancer Elements, Genetic / immunology*
  • Humans
  • Interferon-gamma / antagonists & inhibitors
  • Interferon-gamma / biosynthesis*
  • Interferon-gamma / genetics*
  • Janus Kinase 1
  • Milk Proteins / genetics
  • Milk Proteins / metabolism
  • Nuclear Proteins / metabolism
  • Phosphorylation
  • Promoter Regions, Genetic / immunology
  • Protein Binding / genetics
  • Protein Binding / immunology
  • Protein Kinase Inhibitors / pharmacology
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Response Elements / immunology
  • STAT5 Transcription Factor
  • Signal Transduction / genetics*
  • Signal Transduction / immunology*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism
  • Trans-Activators / physiology*
  • Transcriptional Activation / immunology*
  • Tumor Suppressor Proteins
  • Tyrphostins / pharmacology
  • Up-Regulation / immunology

Substances

  • CD2 Antigens
  • DNA-Binding Proteins
  • Milk Proteins
  • Nuclear Proteins
  • Protein Kinase Inhibitors
  • STAT5 Transcription Factor
  • STAT5A protein, human
  • STAT5B protein, human
  • Trans-Activators
  • Tumor Suppressor Proteins
  • Tyrphostins
  • alpha-cyano-(3,4-dihydroxy)-N-benzylcinnamide
  • Interferon-gamma
  • Protein-Tyrosine Kinases
  • JAK1 protein, human
  • Janus Kinase 1