The primary function of RNA binding by the influenza A virus NS1 protein in infected cells:: Inhibiting the 2′-5′ oligo (A) synthetase/RNase L pathway
The primary function of RNA binding by the influenza A virus NS1 protein in infected cells:: Inhibiting the 2′-5′ oligo (A) synthetase/RNase L pathway
复制标题
DOI：
10.1073/pnas.0602184103
复制
发表时间：
2006-05-02
影响因子：
11.1
通讯作者：
Krug, RM
中科院分区：
文献类型：
--
作者：
Min, JY;Krug, RM
甲型流感病毒的NS 1蛋白（NS 1A蛋白）是一种多功能蛋白，其对抗细胞抗病毒活性并且是毒力因子。其N末端RNA结合结构域结合双链RNA。dsRNA结合所绝对需要的唯一氨基酸是位置38处的R。为了鉴定这种dsRNA结合活性在甲型流感病毒感染过程中的作用，我们产生了表达含有RNA结合结构域的NS 1A蛋白的重组甲型流感病毒/Udorn/72病毒，其中R38突变为A。该R38 A突变病毒是高度减毒的，并且突变NS 1A蛋白与WT蛋白一样定位于细胞核中。使用R38 A突变病毒，我们确定N51 A蛋白的dsRNA结合不抑制IFN-β mRNA的产生。相反，我们证明这种dsRNA结合活性的主要作用是保护病毒免受IFN-β诱导的抗病毒状态。用IFN-β预处理A549细胞6 h不抑制WT Udorn病毒的复制，而R38 A突变病毒的复制被抑制1，000倍。在A549细胞和小鼠敲除细胞中使用RNA干扰，我们表明这种对IFN-β诱导的抗病毒活性的敏感性增强主要是由于RNase L的激活。因为RNase L的活化完全依赖于2 '-5'寡聚（A）合成酶（OAS）的dsRNA活化，所以NS 1A蛋白在病毒感染的细胞中与dsRNA结合的主要作用可能是将dsRNA与2 '-5' OAS隔离。
The NS1 protein of influenza A virus (NS1A protein) is a multifunctional protein that counters cellular antiviral activities and is a virulence factor. Its N-terminal RNA-binding domain binds dsRNA. The only amino acid absolutely required for dsRNA binding is the R at position 38. To identify the role of this dsRNA-binding activity during influenza A virus infection, we generated a recombinant influenza A/Udorn/72 virus expressing an NS1A protein containing an RNA-binding domain in which R38 is mutated to A. This R38A mutant virus is highly attenuated, and the mutant NS1A protein, like the WT protein, is localized in the nucleus. Using the R38A mutant virus, we establish that dsRNA binding by the N51A protein does not inhibit production of IFN-beta mRNA. Rather, we demonstrate that the primary role of this dsRNA-binding activity is to protect the virus against the antiviral state induced by IFN-beta. Pretreatment of A549 cells with IFN-beta for 6 h did not inhibit replication of WT Udorn virus, whereas replication of R38A mutant virus was inhibited 1,000-fold. Using both RNA interference in A549 cells and mouse knockout cells, we show that this enhanced sensitivity to IFN-beta-induced antiviral activity is due predominantly to the activation of RNase L. Because activation of RNase L is totally dependent on dsRNA activation of 2'-5' oligo (A) synthetase (OAS), it is likely that the primary role of dsRNA binding by the NS1A protein in virus-infected cells is to sequester dsRNA away from 2'-5' OAS.