A hybrid IRF9-STAT2 protein recapitulates interferon-stimulated gene expression and antiviral response
A hybrid IRF9-STAT2 protein recapitulates interferon-stimulated gene expression and antiviral response
复制标题
DOI：
10.1074/jbc.m212972200
复制
发表时间：
2003-04-11
影响因子：
4.8
通讯作者：
Horvath, CM
中科院分区：
文献类型：
--
作者：
Kraus, TA;Lau, JF;Horvath, CM
I型干扰素（IFN）信号传导诱导异源三聚体转录复合物，IFN刺激基因因子（ISGF）3，其含有STAT 1、STAT 2和DNA结合亚基，干扰素调节因子（IRF）9。由于IRF 9在没有IFN刺激的情况下靶向细胞核，因此使用GAL 4 DNA结合结构域融合系统检查IRF 9蛋白用于基因调节的潜力。GAL 4-IRF 9在报告基因测定中具有转录活性，但在细胞STAT 1和STAT 2不存在的情况下没有。然而，惰性IRF 9蛋白通过与STAT 2的C-末端转录激活结构域或疱疹病毒VP 16的酸性激活结构域融合而容易地转化为组成型活性ISGF 3样激活剂。IRF 9杂合体靶向内源性ISGF 3靶基因座并可激活其转录。此外，IRF 9-STAT 2融合体的表达可以重现I型IFN生物学应答，产生保护细胞免受病毒诱导的细胞病变效应并抑制病毒复制的细胞抗病毒状态。通过调节IRF 9-STAT 2杂合蛋白表达产生的抗病毒状态不依赖于自分泌IFN信号传导，并抑制RNA和DNA病毒。
Type I interferon (IFN) signaling induces the heterotrimeric transcription complex, IFN-stimulated gene factor (ISGF) 3, which contains STAT1, STAT2, and the DNA binding subunit, interferon regulatory factor (IRF) 9. Because IRF9 is targeted to the nucleus in the absence of IFN stimulation, the potential of IRF9 protein for gene regulation was examined using a GAL4 DNA binding domain fusion system. GAL4-IRF9 was transcriptionally active in reporter gene assays but not in the absence of cellular STAT1 and STAT2. However, the inert IRF9 protein was readily converted to a constitutively active ISGF3-like activator by fusion with the C-terminal transcriptional activation domain of STAT2 or the acidic activation domain of herpesvirus VP16. The IRF9 hybrids are targeted to endogenous ISGF3 target loci and can activate their transcription. Moreover, expression of the IRF9-STAT2 fusion can recapitulate the type I IFN biological response, producing a cellular antiviral state that protects cells from virus-induced cytopathic effects and inhibits virus replication. The antiviral state generated by regulated IRF9-STAT2 hybrid protein expression is independent of autocrine IFN signaling and inhibits both RNA and DNA viruses.