title: IFN-gamma up-regulates IL-18 gene expression via IFN consensus sequence-binding protein and activator protein-1 elements in macrophages.
abstract: Constitutive IL-18 expression is detected from many different cells, including macrophages, keratinocytes, and osteoblasts. It has been known that IL-18 gene expression is regulated by two different promoters (p1 promoter and p2 promoter). When RAW 264.7 macrophages were treated with IFN-gamma, IL-18 gene expression was increased in a dose- and time-dependent manner. IFN-gamma activated the inducible promoter 1, but not the constitutive promoter 2. Mutagenesis studies indicated that an IFN consensus sequence-binding protein (ICSBP) binding site between -39 and -22 was critical for the IFN-gamma inducibility. EMSA using an ICSBP oligonucleotide probe showed that IFN-gamma treatment increased the formation of DNA-binding complex, which was supershifted with anti-IFN regulatory factor-1 Ab and anti-ICSBP Ab. Another element, an AP-1 site between -1120 and -1083, was important. EMSA using an AP-1-specific oligonucleotide demonstrated that IFN-gamma or LPS treatment increased the AP-1-binding activity. The addition of anti-c-Jun Ab or anti-c-Fos Ab to IFN-gamma- or LPS-treated nuclear extracts resulted in the reduction of AP-1 complex or the formation of a supershifted complex. Taken together, these results indicate that IFN-gamma increased IL-18 gene expression via ICSBP and AP-1 elements.
authors.affiliation: Laboratory of Immunology, Korea Research Institute of Bioscience and Biotechnology, Yusong, Taejon, Republic of Korea.
authors.forename: Y M
authors.initials: YM
authors.lastname: Kim
authors.forename: J Y
authors.initials: JY
authors.lastname: Im
authors.forename: S H
authors.initials: SH
authors.lastname: Han
authors.forename: H S
authors.initials: HS
authors.lastname: Kang
authors.forename: I
authors.initials: I
authors.lastname: Choi
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D016384:Consensus Sequence / Q000235:genetics / Q000276:immunology; D005786:Gene Expression Regulation / Q000276:immunology; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma / Q000502:physiology*; D020382:Interleukin-18 / Q000096:biosynthesis / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000235:genetics / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic / Q000276:immunology; D012097:Repressor Proteins / Q000502:physiology*; D018808:Transcription Factor AP-1 / Q000502:physiology*; D015854:Up-Regulation / Q000276:immunology*; D000099185:Interferon Regulatory Factor-8
chemical_list: D050835:Interferon Regulatory Factors; D007371:Interferon-gamma; D020382:Interleukin-18; D008070:Lipopolysaccharides; D012097:Repressor Proteins; D018808:Transcription Factor AP-1; D000099185:Interferon Regulatory Factor-8