BINDING OF THE INFLUENZA-VIRUS NS1 PROTEIN TO DOUBLE-STRANDED-RNA INHIBITS THE ACTIVATION OF THE PROTEIN-KINASE THAT PHOSPHORYLATES THE ELF-2 TRANSLATION INITIATION-FACTOR
BINDING OF THE INFLUENZA-VIRUS NS1 PROTEIN TO DOUBLE-STRANDED-RNA INHIBITS THE ACTIVATION OF THE PROTEIN-KINASE THAT PHOSPHORYLATES THE ELF-2 TRANSLATION INITIATION-FACTOR
复制标题
DOI：
10.1006/viro.1995.9937
复制
发表时间：
1995-12-01
期刊：
影响因子：
3.7
通讯作者：
KRUG, RM
中科院分区：
文献类型：
--
作者：
LU, Y;WAMBACH, M;KRUG, RM
甲型流感病毒的 NS1 蛋白不仅与聚腺苷酸 (poly(A)) 和 U6 小核 RNA (snRNA) 中的茎凸出区域结合，而且还与双链 (ds) RNA 结合。 NS1 蛋白突变体的结合测定表明，先前鉴定的 NS1 蛋白的 RNA 结合结构域是与 ds RNA 结合以及与 Poly(A) 和 U6 snRNA 结合所必需的。此外，dsRNA 与 U6 snRNA 竞争与 NS1 蛋白的结合，这与两种 RNA 在蛋白上共享相同的结合位点一致。由于与 dsRNA 结合，NS1 蛋白在体外阻断 dsRNA 激活蛋白激酶 (PKR) 的激活。该激酶磷酸化真核翻译起始因子 2 (elF-2 α) 的 cu 亚基，导致翻译起始速率降低。使用纯化的 PKR 和纯化的 eF2 进行的测定表明，NS1 蛋白阻断 PKR 的 dsRNA 激活，并且使用网织红细胞提取物的实验表明，NS1 蛋白阻断 PKR 的 dsRNA 激活引起的翻译抑制。讨论了这些结果对流感病毒感染细胞中发生的控制机制的影响。 (C) 1995 学术出版社
The NS1 protein of influenza A virus binds not only to poly(A) and a stem-bulge region in U6 small nuclear RNA (snRNA), but also to double-stranded (ds) RNA. Binding assays with NS1 protein mutants established that the previously identified RNA-binding domain of the NS1 protein is required for binding to ds RNA as well as for binding to poly(A) and U6 snRNA. In addition, dsRNA competed with U6 snRNA for binding to the NS1 protein, consistent with both RNAs sharing the same binding site on the protein. As a consequence of its binding to dsRNA, the NS1 protein blocks the activation of the dsRNA-activated protein kinase (PKR) in vitro. This kinase phosphorylates the cu subunit of eukaryotic translation initiation factor 2 (elF-2 alpha), leading to a decrease in the rate of initiation of translation. Assays using purified PKR and purified elF2 demonstrated that the NS1 protein blocks the dsRNA activation of PKR, and experiments using reticulocyte extracts showed that the NS1 protein blocks the inhibition of translation caused by dsRNA activation of PKR. The implications of these results for control mechanisms occurring in influenza virus-infected cells are discussed. (C) 1995 Academic Press, Inc.