The c-rel protooncogene product c-Rel but not NF-kappa B binds to the intronic region of the human interferon-gamma gene at a site related to an interferon-stimulable response element

Proc Natl Acad Sci U S A. 1992 Mar 1;89(5):1740-4. doi: 10.1073/pnas.89.5.1740.

Abstract

Interferon-gamma (IFN-gamma) is an important immunoregulatory protein that is expressed usually only in large granular lymphocytes and T cells. The gene encoding IFN-gamma was previously found to contain an intronic enhancer element that was not tissue-specific in its activity, despite the restricted expression of the intact IFN-gamma-encoding gene. Using nuclear extracts from the human T-cell line Jurkat, we have now identified two protein-binding regions in this intronic enhancer element. One of the protected regions has strong partial identify to the NF-kappa B site present in the promoter region of the human interleukin 2-encoding gene. Based on this observation and recent reports of the interaction of the c-rel protooncogene product (c-Rel) with NF-kappa B sites, we determined whether c-Rel could interact with the intronic enhancer element in the human IFN-gamma genomic DNA. Most surprisingly, gel-shift analysis, using c-Rel expressed in Escherichia coli established that c-Rel binds specifically to the IFN-gamma intronic DNA but not to the interleukin 2-like NF-kappa B site. Additional studies with antibodies prepared against c-Rel peptides verified specificity of the interaction of c-Rel with this binding site. In addition, using an affinity-purified p50 subunit of the NF-kappa B complex, we observed that the p50 protein did not bind to this additional c-Rel-binding site. Furthermore, nucleotide sequence analysis of this DNA region revealed a strong similarity of the additional c-Rel-binding site to a previously identified IFN-stimulable response element. These data show that c-Rel can interact with DNA regions distinct from that recognized by NF-kappa B and may, in fact, be involved in transcriptional regulation of the IFN-stimulable genes via the IFN-stimulable response element.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation
  • Humans
  • In Vitro Techniques
  • Interferon-gamma / genetics*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • NF-kappa B / metabolism*
  • Oligodeoxyribonucleotides / chemistry
  • Protein Binding
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-rel
  • RNA, Messenger / genetics
  • Regulatory Sequences, Nucleic Acid
  • Sequence Homology, Nucleic Acid

Substances

  • DNA-Binding Proteins
  • NF-kappa B
  • Oligodeoxyribonucleotides
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-rel
  • RNA, Messenger
  • Interferon-gamma