title: Complex formation of the interferon (IFN) consensus sequence-binding protein with IRF-1 is essential for murine macrophage IFN-gamma-induced iNOS gene expression.
abstract: This study describes the role of the interferon (IFN) consensus sequence-binding protein (ICSBP or IRF-8) in iNOS gene expression by murine macrophages. An ICSBP binding site in the iNOS promoter region (-923 to -913) was identified using an electrophoretic mobility shift assay and chromatin co-immunoprecipitation. Overexpression of ICSBP greatly enhanced IFN-gamma-induced iNOS promoter activation in RAW264.7 cells, and IFN-gamma-induced iNOS promoter activation was abolished in ICSBP-/- macrophages. Furthermore, transduction of retrovirus-ICSBP in ICSBP-/- macrophages rescued IFN-gamma-induced iNOS gene expression. However, transduction of retrovirus-ICSBP in the absence of IFN-gamma activation did not induce iNOS expression in either RAW264.7 cells or ICSBP-/- macrophages. Interestingly, ICSBP alone transduced into ICSBP-/- macrophages did not bind to IFN-stimulated response element site (-923 to -913) of the iNOS promoter region, although following activation with IFN-gamma, a DNA.protein complex was formed that contains ICSBP and IRF-1. Co-transduction of ICSBP with IRF-1 clearly induces nitric oxide production. In addition, interleukin-4 inhibits IFN-gamma-induced iNOS gene expression by attenuating the physical interaction of ICSBP with IRF-1. Complex formation of ICSBP with IRF-1 is essential for iNOS expression, and interleukin-4 attenuates the physical interaction of ICSBP with IRF-1 resulting in the inhibition of INOS gene expression.
authors.affiliation: Immunobiology Center, Mount Sinai School of Medicine, New York, New York 10029, USA. xionghbl@yahoo.com
authors.forename: Huabao
authors.initials: H
authors.lastname: Xiong
authors.forename: Chen
authors.initials: C
authors.lastname: Zhu
authors.forename: Hongxing
authors.initials: H
authors.lastname: Li
authors.forename: Frank
authors.initials: F
authors.lastname: Chen
authors.forename: Lloyd
authors.initials: L
authors.lastname: Mayer
authors.forename: Keiko
authors.initials: K
authors.lastname: Ozato
authors.forename: Jay C
authors.initials: JC
authors.lastname: Unkeless
authors.forename: Scott E
authors.initials: SE
authors.lastname: Plevy
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D050856:Interferon Regulatory Factor-1; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma / Q000378:metabolism*; D007372:Interferons / Q000378:metabolism*; D015847:Interleukin-4 / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D010750:Phosphoproteins / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism* / Q000502:physiology*; D012190:Retroviridae / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D014161:Transduction, Genetic; D014162:Transfection; D000099185:Interferon Regulatory Factor-8
chemical_list: D004247:DNA; D004268:DNA-Binding Proteins; D049452:Green Fluorescent Proteins; D050856:Interferon Regulatory Factor-1; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma; D007372:Interferons; D015847:Interleukin-4; D008164:Luminescent Proteins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D010750:Phosphoproteins; D012097:Repressor Proteins; D000099185:Interferon Regulatory Factor-8; C494258:Irf1 protein, mouse; C496317:Nos2 protein, mouse