Priming of influenza viral RNA transcription by capped heterologous RNAs.
Priming of influenza viral RNA transcription by capped heterologous RNAs.
复制标题
加帽异源 RNA 引发流感病毒 RNA 转录。
DOI：
10.1007/978-3-642-68123-3_6
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发表时间：
1981
影响因子：
--
通讯作者：
Krug,RM
中科院分区：
文献类型：
--
作者：
Krug,RM
流感病毒是负链RNA病毒，即，病毒信使RNA（mRNA）与基因组RNA（其是分段的）互补，并且病毒体含有将基因组RNA转录成病毒mRNA的酶系统。这种病毒采用独特的机制来启动其mRNA的合成。具体地，病毒体相关转录酶系统需要蚕食加帽的异源RNA，即，在一些实施方案中，病毒mRNA可以与真核细胞mRNA和/或其前体结合，以合成病毒mRNA。该过程涉及通过病毒体相关的核酸内切酶切下真核mRNA 5 '端附近的一小段，然后利用该RNA片段作为引物来启动病毒mRNA的合成。在所有哺乳动物细胞mRNA的5 J-末端发现的甲基化帽结构（m7 GpppNm，其中Nm = 2' -O-甲基化核苷）是用作引物并从细胞转移到病毒mRNA的RNA片段的一部分，并且该帽结构对于病毒核酸酶和引发反应是绝对必需的。事实上，5;- 甲基化帽结构对于引发流感病毒mRNA合成比对于其先前已显示起作用的过程（无细胞系统中mRNA的翻译）更严格地需要。这种病毒mRNA合成的机制解释了为什么流感病毒需要宿主细胞核RNA聚合酶II的功能才能复制：新合成的宿主mRNA和/或其前体需要作为病毒mRNA合成的引物。
Influenza virus is a negative-stranded RNA virus, i.e., the viral messenger RNA (mRNA) is complementary to the genome RNA (which is segmented), and the virion contains the enzyme system which transcribes the genome RNA into the viral mRNA. This virus employs a unique mechanism for the initiation of the synthesis of its mRNA. Specifically, the virion-associated transcriptase system needs to cannibalize capped heterologous RNAs, i.e., eukaryotic cellular mRNAs and/or their precursors, in order to synthesize the viral mRNA. This process involves the clipping off by a virion-associated endonuclease of a small piece of the eukaryotic mRNA near its 5’-end, followed by the utilization of this RNA fragment as a primer to initiate the synthesis of the viral mRNA. The methylated cap structure (m7GpppNm, where Nm = 2’ -O-methylated nucleoside) found at the 5J -end of all mammalian cellular mRNAs is part of the RNA fragment that is used as primer and transferred from the cellular to the viral mRNA, and this cap structure is absolutely necessary for the viral nuclease and the priming reaction. In fact, the 5;-methylated cap structure is more stringently required for priming influenza viral mRNA synthesis than for the process in which it had previously been shown to play a role, the translation of mRNAs in cell-free systems. This mechanism for viral mRNA synthesis explains why influenza virus requires the functioning of the host-cell nuclear RNA polymerase II in order to replicate: newly synthesized host mRNAs and/or their precursors are needed as primers for viral mRNA synthesis.