Differential regulation of human interferon A gene expression by interferon regulatory factors 3 and 7.
Differential expression of the human interferon A (IFN-A) gene cluster is modulated following paramyxovirus infection by the relative amounts of active interferon regulatory factor 3 (IRF-3) and IRF-7. IRF-3 expression activates predominantly IFN-A1 and IFN-B, while IRF-7 expression induces multiple IFN-A genes. IFN-A1 gene expression is dependent on three promoter proximal IRF elements (B, C, and D modules, located at positions -98 to -45 relative to the mRNA start site). IRF-3 binds the C module of IFN-A1, while other IFN-A gene promoters are responsive to the binding of IRF-7 to the B and D modules. Maximal expression of IFN-A1 is observed with complete occupancy of the three modules in the presence of IRF-7. Nucleotide substitutions in the C modules of other IFN-A genes disrupt IRF-3-mediated transcription, whereas a G/A substitution in the D modules enhances IRF7-mediated expression. IRF-3 exerts dual effects on IFN-A gene expression, as follows: a synergistic effect with IRF-7 on IFN-A1 expression and an inhibitory effect on other IFN-A gene promoters. Chromatin immunoprecipitation experiments reveal that transient binding of both IRF-3 and IRF-7, accompanied by CBP/p300 recruitment to the endogenous IFN-A gene promoters, is associated with transcriptional activation, whereas a biphasic recruitment of IRF-3 and CBP/p300 represses IFN-A gene expression. This regulatory mechanism contributes to differential expression of IFN-A genes and may be critical for alpha interferon production in different cell types by RIG-I-dependent signals, leading to innate antiviral immune responses.
Génin
Pierre
P
UPR 2228-CNRS, Laboratoire de Régulation Transcriptionnelle et Maladies Génétiques, UFR Biomédicale des Saints-Pères, Université Paris Descartes, 45 rue des Saints-Pères, 75270 Paris Cedex 06, France.
Lin
Rongtuan
R
Hiscott
John
J
Civas
Ahmet
A
D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004247:DNA / Q000235:genetics; D006801:Humans; D007113:Immunity, Innate; D050838:Interferon Regulatory Factor-3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D050839:Interferon Regulatory Factor-7 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D007370:Interferon Type I / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D029082:Sendai virus / Q000276:immunology / Q000472:pathogenicity; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction; D015533:Transcriptional Activation; D050880:p300-CBP Transcription Factors / Q000378:metabolism
C494232:IRF3 protein, human; C494234:IRF7 protein, human; D050838:Interferon Regulatory Factor-3; D050839:Interferon Regulatory Factor-7; D007370:Interferon Type I; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D004247:DNA; D050880:p300-CBP Transcription Factors