Preferential binding sites for interferon regulatory factors 3 and 7 involved in interferon-A gene transcription

J Mol Biol. 2002 Mar 8;316(5):1009-22. doi: 10.1006/jmbi.2001.5401.

Abstract

Transcription of the murine interferon-A4 (IFN-A4) gene is mediated by a virus responsive element (VRE-A4) located in the promoter proximal [-120 to -43] region. VRE-A4 contains four DNA modules (A to D) which cooperate for maximal IFN-A4 activation following virus infection. The differential expression between the highly expressed IFN-A4 and the weakly inducible IFN-A11 gene promoters is essentially due to point mutations within the C and D modules of the virus-responsive element VRE-A11. We now demonstrate that in murine L929 and human 293 cells, transcription factors IRF-3 and IRF-7, which are potent activators of virus-induced type I IFN transcription, differentially affect IFN-A4 and IFN-A11 promoter activities. Using electrophoretic mobility shift assays and DNase I footprinting data, our studies demonstrate that the AB modules correspond to a preferential site for IRF-7, whereas the C module is preferentially recognized by IRF-3. Furthermore, transfection of reporter constructs driven by four copies of different GAAANN hexameric motifs found within VRE-A4 indicates that the NN residues of these hexameric sequences define the preferential binding sites for IRF-3 or IRF-7. Together, these experiments clarify the molecular basis for differential expression of IFN-A genes following virus infection by delineating the sequence requirements for IRF association with the virus responsive elements of the IFN-A genes.

Publication types

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

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites
  • Cell Line
  • DNA Footprinting
  • DNA-Binding Proteins / metabolism*
  • Deoxyribonuclease I / metabolism
  • Electrophoretic Mobility Shift Assay
  • Gene Expression Regulation / genetics*
  • Humans
  • Interferon Regulatory Factor-3
  • Interferon Regulatory Factor-7
  • Interferon-alpha / genetics*
  • Mice
  • Molecular Sequence Data
  • Mutation / genetics
  • Promoter Regions, Genetic / genetics
  • Response Elements / genetics*
  • Transcription Factors / metabolism*
  • Transcription, Genetic / genetics*

Substances

  • DNA-Binding Proteins
  • IRF3 protein, human
  • IRF7 protein, human
  • Interferon Regulatory Factor-3
  • Interferon Regulatory Factor-7
  • Interferon-alpha
  • Irf3 protein, mouse
  • Irf7 protein, mouse
  • Transcription Factors
  • Deoxyribonuclease I