Evolutionarily conserved sequence elements that positively regulate IFN-gamma expression in T cells

Proc Natl Acad Sci U S A. 2004 Aug 24;101(34):12622-7. doi: 10.1073/pnas.0400849101. Epub 2004 Aug 10.

Abstract

Our understanding of mechanisms by which the expression of IFN-gamma is regulated is limited. Herein, we identify two evolutionarily conserved noncoding sequence elements (IFNgCNS1 and IFNg CNS2) located approximately 5 kb upstream and approximately 18 kb downstream of the initiation codon of the murine Ifng gene. When linked to the murine Ifng gene (-3.4 to +5.6 kb) and transiently transfected into EL-4 cells, these elements clearly enhanced IFN-gamma expression in response to ionomycin and phorbol 12-myristate 13-acetate and weakly enhanced expression in response to T-bet. A DNase I hypersensitive site and extragenic transcripts at IFNgCNS2 correlated positively with the capacity of primary T cell subsets to produce IFN-gamma. Transcriptionally favorable histone modifications in the Ifng promoter, intronic regions, IFNgCNS2, and, although less pronounced, IFNgCNS1 increased as naïve T cells differentiated into IFN-gamma-producing effector CD8+ and T helper (TH) 1 T cells, but not into TH2 T cells. Like IFN-gamma expression, these histone modifications were T-bet-dependent in CD4+ cells, but not CD8+ T cells. These findings define two distal regulatory elements associated with T cell subset-specific IFN-gamma expression.

Publication types

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

MeSH terms

  • Animals
  • Cells, Cultured
  • Evolution, Molecular*
  • Gene Expression Regulation
  • Histones / metabolism
  • Humans
  • Interferon-gamma / genetics*
  • Interferon-gamma / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Protein Processing, Post-Translational
  • Rats
  • Regulatory Sequences, Nucleic Acid*
  • T-Box Domain Proteins
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology
  • T-Lymphocytes / physiology*
  • Transcription Factors / metabolism
  • Transcription, Genetic

Substances

  • Histones
  • T-Box Domain Proteins
  • T-box transcription factor TBX21
  • Transcription Factors
  • Interferon-gamma