标题：A Kaposi's sarcoma-associated herpesviral protein inhibits virus-mediated induction of type I interferon by blocking IRF-7 phosphorylation and nuclear accumulation
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：8
页码：5573-5578
DOI：10.1073/pnas.082420599
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Interferons constitute the earliest immune response against viral infection. They elicit antiviral effects as well as multiple biological responses involved in cell growth regulation and immune activation. Because the interferon-induced cellular antiviral response is the primary defense mechanism against viral infection, many viruses have evolved strategies to antagonize the inhibitory effects of interferon. Here, we demonstrate a strategy that Kaposi's sarcoma-associated herpesvirus uses to block virus-mediated induction of type I interferon. We found that a viral immediate-early protein, namely ORF45, interacts with cellular interferon-regulatory factor 7 (IRF-7). In consequence, IRF-7 phosphorylation is inhibited and the accumulation of IRF-7 in the nucleus in response to viral infection is blocked. IRF-7 is a transcription regulator that is responsible for virus-mediated activation of type I interferon genes. By blocking the phosphorylation and nuclear translocation of IRF-7, ORF45 efficiently inhibits the activation of interferon and {beta} genes during viral infection. Inhibition of interferon gene expression through a viral protein blocking the activation and nuclear translocation of a crucial transcription factor is a novel mechanism for viral immune evasion.
