title: Identification of IFN regulatory factor-1 binding site in IL-12 p40 gene promoter.
abstract: IL-12 is a heterodimer composed of p40 and p35 and is a key cytokine that functions to protect the host from viral and microbial infections. IL-12 links the innate immune system with the acquired immune system during infection, and induces differentiation of type 1 T cells that play an important role in the eradication of microbes. The induction of the IL-12 p40 gene is regulated by NF-kappaB in the presence of IFN-gamma. IFN-gamma induces IFN regulatory factor-1 (IRF-1), which in turn induces the transcription of the IL-12 p40 gene. However, the IRF-1 binding site in the promoter region of the IL-12 p40 gene has not yet been formally determined. In the present study, we demonstrated that IRF-1 directly binds to the IL-12 p40 gene promoter and identified its binding site. The IRF-1 binding site in the promoter region of the IL-12 p40 gene is shown to be in the -72 to -58 area of the 5'-upstream region. The -63 to -61 position is the critical site within this region for the binding of IRF-1 to the IL-12 p40 gene promoter. While IFN-gamma must be present for IL-12 p40 gene induction, the p35 gene is strongly induced by LPS, even in the absence of IFN-gamma, and therefore the induction of the p35 gene is IRF-1 independent.
authors.affiliation: Department of Immunology and Host Defenses, Ehime University School of Medicine, Shigenobu, Japan.
authors.forename: Saho
authors.initials: S
authors.lastname: Maruyama
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Sumita
authors.forename: Hua
authors.initials: H
authors.lastname: Shen
authors.forename: Makoto
authors.initials: M
authors.lastname: Kanoh
authors.forename: Xin
authors.initials: X
authors.lastname: Xu
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Sato
authors.forename: Masahito
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Hiroto
authors.initials: H
authors.lastname: Shinomiya
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Asano
mesh_terms: D020121:5' Untranslated Regions / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D005786:Gene Expression Regulation / Q000276:immunology; D050856:Interferon Regulatory Factor-1; D050832:Interferon-Stimulated Gene Factor 3; D050834:Interferon-Stimulated Gene Factor 3, gamma Subunit; D007371:Interferon-gamma / Q000378:metabolism*; D018664:Interleukin-12 / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D053765:Interleukin-12 Subunit p35; D053762:Interleukin-12 Subunit p40; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000378:metabolism* / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000276:immunology*; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D021122:Protein Subunits / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic / Q000276:immunology; D015533:Transcriptional Activation; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
chemical_list: D020121:5' Untranslated Regions; D004268:DNA-Binding Proteins; D050856:Interferon Regulatory Factor-1; D050832:Interferon-Stimulated Gene Factor 3; D050834:Interferon-Stimulated Gene Factor 3, gamma Subunit; D053765:Interleukin-12 Subunit p35; D053762:Interleukin-12 Subunit p40; C494258:Irf1 protein, mouse; C494228:Isgf3g protein, mouse; D010750:Phosphoproteins; D021122:Protein Subunits; D012333:RNA, Messenger; D014157:Transcription Factors; D018664:Interleukin-12; D007371:Interferon-gamma