Hypomethylation of the proximal and intronic regulatory regions of the IFN-gamma gene is not essential for its transcription by naive CD4+ T cells cultured with IL-4

Immunol Lett. 1999 Aug 3;69(2):239-45. doi: 10.1016/s0165-2478(99)00078-4.

Abstract

Recently, long-term preculture with IL-4 or IL-7 has been reported to induce IFN-gamma-producing ability in naive CD4+ T cells without stimulation via TCR. The mechanism of IFN-gamma-transcription in naive CD4+ T cells precultured with IL-4 was analyzed and compared with that in typical Th1 cells by focusing on the TATA proximal and first intronic regulatory regions of the IFN-gamma gene. Both regulatory regions in these IL-4-primed naive CD4+ T cells, which produce a large amount of IFN-gamma upon stimulation with PMA and ionomycin, were completely methylated in contrast to the same hypomethylated regions in Th1 cells. DNase I hypersensitive site analysis suggested that both regulatory regions in IL-4-primed naive CD4+ T cells were not active for IFN-gamma-expression. Moreover, we demonstrated that the composition of transcriptional factors that can bind to the proximal regulatory region is different between IL-4-primed naive CD4+ T cells and Th1 cells. These results indicated that the transcriptional machinery involved in the expression of the IFN-gamma gene by CD4+ T cells varied depending on their modes of differentiation in both the responsive regulatory regions and the specific nuclear factors.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD4-Positive T-Lymphocytes / drug effects*
  • CD4-Positive T-Lymphocytes / metabolism
  • Cell Differentiation
  • Cells, Cultured
  • DNA / metabolism
  • DNA Methylation*
  • Fetal Blood / cytology
  • Gene Expression Regulation / drug effects
  • Humans
  • Interferon-gamma / genetics*
  • Interferon-gamma / pharmacology
  • Interleukin-4 / pharmacology*
  • Introns / genetics*
  • Ionomycin / pharmacology
  • Leucine / analogs & derivatives
  • Leucine / pharmacology
  • Recombinant Proteins
  • Regulatory Sequences, Nucleic Acid*
  • TATA Box / genetics*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Th1 Cells / drug effects
  • Th1 Cells / metabolism
  • Transcription Factors / metabolism
  • Transcription, Genetic / drug effects

Substances

  • Recombinant Proteins
  • Transcription Factors
  • Interleukin-4
  • leucine methyl ester
  • Ionomycin
  • Interferon-gamma
  • DNA
  • Leucine
  • Tetradecanoylphorbol Acetate