mRNA decay during herpes simplex virus (HSV) infections: Protein-protein interactions involving the HSV virion host shutoff protein and translation factors eIF4H and eIF4A
mRNA decay during herpes simplex virus (HSV) infections: Protein-protein interactions involving the HSV virion host shutoff protein and translation factors eIF4H and eIF4A
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DOI：
10.1128/jvi.79.15.9651-9664.2005
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发表时间：
2005-08-01
影响因子：
5.4
通讯作者：
Read, GS
中科院分区：
文献类型：
--
作者：
Feng, PH;Everly, DN;Read, GS
在裂解感染期间，单纯疱疹病毒的病毒体宿主关闭 (Vhs) 蛋白加速宿主和病毒 mRNA 的降解。这样做，它有助于将细胞从宿主重定向到病毒蛋白质合成，并促进不同病毒基因的顺序表达。 Vhs 与细胞翻译起始因子 eIF4H 相互作用，并且消除其 mRNA 降解活性的几个点突变也消除了其结合 eIF4H 的能力。此外，含有细菌表达的 Vhs 和谷胱甘肽 S-转移酶 (GST)-eIF4H 融合蛋白的复合物具有 RNase 活性。 eIF4H 与 eIF4B 具有序列同源性区域，并且它似乎在功能上相似，因为两者都刺激 eIF4A（mRNA 帽结合复合物 eIF4F 的组成部分）的 RNA 解旋酶活性。我们表明，在酵母双杂交系统和 GST Pull-down 测定中，eIF4H 与 eIF4A 发生物理相互作用，并且这两种蛋白质可以从哺乳动物细胞中共免疫沉淀。 Vhs 还在 GST 下拉和免疫共沉淀测定中与 eIF4A 相互作用。 Vhs 和 eIF4H 的定点诱变揭示了各自的残基，这些残基对于它们的相互相互作用很重要，但对于它们与 eIF4A 的相互作用并不重要。因此，Vhs、eIF4H 和 eIF4A 包含一组蛋白质，其中每一个都能够与另外两个直接相互作用。它们是作为三方复合体同时相互作用还是依次相互作用尚不清楚。这些数据表明了一种将 mRNA 的降解与其翻译联系起来以及将 Vhs 靶向 mRNA 和翻译起始区域的机制。
During lytic infections, the virion host shutoff (Vhs) protein of herpes simplex virus accelerates the degradation of both host and viral mRNAs. In so doing, it helps redirect the cell from host to viral protein synthesis and facilitates the sequential expression of different viral genes. Vhs interacts with the cellular translation initiation factor eIF4H, and several point mutations that abolish its mRNA degradative activity also abrogate its ability to bind eIF4H. In addition, a complex containing bacterially expressed Vhs and a glutathione S-transferase (GST)-eIF4H fusion protein has RNase activity. eIF4H shares a region of sequence homology with eIF4B, and it appears to be functionally similar in that both stimulate the RNA helicase activity of eIF4A, a component of the mRNA cap-binding complex eIF4F. We show that eIF4H interacts physically with eIF4A in the yeast two-hybrid system and in GST pull-down assays and that the two proteins can be coimmunoprecipitated from mammalian cells. Vhs also interacts with eIF4A in GST pull-down and coimmunoprecipitation assays. Site-directed mutagenesis of Vhs and eIF4H revealed residues of each that are important for their mutual interaction, but not for their interaction with eIF4A. Thus, Vhs, eIF4H, and eIF4A comprise a group of proteins, each of which is able to interact directly,with the other two. Whether they interact simultaneously as a tripartite complex or sequentially is unclear. The data suggest a mechanism for linking the degradation of an mRNA to its translation and for targeting Vhs to mRNAs and to regions of translation initiation.