HMG I(Y) interferes with the DNA binding of NF-AT factors and the induction of the interleukin 4 promoter in T cells

Proc Natl Acad Sci U S A. 1996 Dec 24;93(26):15311-6. doi: 10.1073/pnas.93.26.15311.

Abstract

HMG I(Y) proteins bind to double-stranded A + T oligonucleotides longer than three base pairs. Such motifs form part of numerous NF-AT-binding sites of lymphokine promoters, including the interleukin 4 (IL-4) promoter. NF-AT factors share short homologous peptide sequences in their DNA-binding domain with NF-kappa B factors and bind to certain NF-kappa B sites. It has been shown that HMG I(Y) proteins enhance NF-kappa B binding to the interferon beta promoter and virus-mediated interferon beta promoter induction. We show that HMG I(Y) proteins exert an opposite effect on the DNA binding of NF-AT factors and the induction of the IL-4 promoter in T lymphocytes. Introduction of mutations into a high-affinity HMG I(Y)-binding site of the IL-4 promoter, which decreased HMG I(Y)-binding to a NF-AT-binding sequence, the Pu-bB (or P) site, distinctly increased the induction of the IL-4 promoter in Jurkat T leukemia cells. High concentrations of HMG I(Y) proteins are able to displace NF-ATp from its binding to the Pu-bB site. High HMG I(Y) concentrations are typical for Jurkat cells and peripheral blood T lymphocytes, whereas E14 T lymphoma cells and certain T helper type 2 cell clones contain relatively low HMG I(Y) concentrations. Our results indicate that HMG I(Y) proteins do not cooperate, but instead compete with NF-AT factors for the binding to DNA even though NF-AT factors share some DNA-binding to DNA even though NF-AT factors share some DNA-binding properties with NF-kB factors. This competition between HMG I(Y) and NF-AT proteins for DNA binding might be due to common contacts with minor groove nucleotides of DNA and may be one mechanism contributing to the selective IL-4 expression in certain T lymphocyte populations, such as T helper type 2 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Binding, Competitive
  • Cell Line
  • Cloning, Molecular
  • DNA-Binding Proteins / metabolism*
  • Glutathione Transferase / biosynthesis
  • HMGA1a Protein
  • HeLa Cells
  • High Mobility Group Proteins / metabolism*
  • Humans
  • Interleukin-4 / biosynthesis*
  • Interleukin-4 / genetics*
  • Leukemia, T-Cell
  • Lymphocyte Activation
  • Lymphoma, T-Cell
  • Mice
  • Mutagenesis, Site-Directed
  • NF-kappa B / metabolism
  • NFATC Transcription Factors
  • Nuclear Proteins*
  • Oligodeoxyribonucleotides / metabolism
  • Oligodeoxyribonucleotides / pharmacology
  • Promoter Regions, Genetic*
  • Protein Binding
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / metabolism
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Transcription Factors / metabolism*

Substances

  • DNA-Binding Proteins
  • High Mobility Group Proteins
  • NF-kappa B
  • NFATC Transcription Factors
  • Nuclear Proteins
  • Oligodeoxyribonucleotides
  • Recombinant Fusion Proteins
  • Transcription Factors
  • HMGA1a Protein
  • Interleukin-4
  • Glutathione Transferase
  • Tetradecanoylphorbol Acetate