title: Nitric oxide inhibits the transcription repressor Yin-Yang 1 binding activity at the silencer region of the Fas promoter: a pivotal role for nitric oxide in the up-regulation of Fas gene expression in human tumor cells.
abstract: NO has been increasingly implicated in control of the transcriptional machinery and serves as an intracellular second messenger to modify gene expression. We have demonstrated that NO up-regulated Fas receptor expression in ovarian carcinoma cell lines, albeit the mechanism involved is not known. Thus, we hypothesized that NO, directly or indirectly, may modify the transcriptional machinery that is responsible for the increased expression of the Fas gene. We examined the effect of NO on Fas gene expression using a Fas promoter-driven luciferase reporter system. Transient transfection of AD10 cells with pGL-3-FasP demonstrated that the IFN-gamma-dependent NO generation increases the trans-activation of the Fas promoter, and this increase was blocked by the NOS inhibitor (N(G)-monomethyl-L-arginine), but could be restored by the addition of the NO donor S-nitroso-N-acetylpenicillamine. Systematic deletion of the Fas promoter revealed that the functional region responsible for the NO-mediated effect was located at the silencer region, suggesting that NO may be responsible for the disruption of a repressor mechanism. We demonstrate that NO up-regulates the expression of the Fas receptor on AD10 cells via the specific inactivation of the transcription repressor yin-yang 1 DNA binding activity to the silencer region of the Fas promoter. These findings reveal a new mechanism of NO-mediated gene regulation by interfering with a repressor transcription factor at the silencer region of the Fas promoter.
authors: Department of Microbiology, Immunology, and Molecular Genetics, and Jonsson Comprehensive Cancer Center, University of California School of Medicine, Los Angeles, CA 90095, USA.
authors: H J
authors: HJ
authors: Garbán
authors: B
authors: B
authors: Bonavida
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000037:antagonists & inhibitors / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology*; D020868:Gene Silencing / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000502:physiology; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000276:immunology*; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis; D012097:Repressor Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism; D020218:Response Elements / Q000276:immunology; D014157:Transcription Factors / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology*; D050986:YY1 Transcription Factor; D019014:fas Receptor / Q000096:biosynthesis / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; D050986:YY1 Transcription Factor; D019014:fas Receptor; D009569:Nitric Oxide; D007371:Interferon-gamma; D004247:DNA