Involvement of Hsp90 in assembly and nuclear import of influenza virus RNA polymerase subunits
Involvement of Hsp90 in assembly and nuclear import of influenza virus RNA polymerase subunits
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DOI：
10.1128/jvi.01917-06
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发表时间：
2007-02-01
影响因子：
5.4
通讯作者：
Nagata, Kyosuke
中科院分区：
文献类型：
--
作者：
Naito, Tadasuke;Momose, Fumitaka;Nagata, Kyosuke
流感病毒 RNA 基因组的转录和复制通过由 PB1、PB2 和 PA 组成的病毒 RNA 依赖性 RNA 聚合酶在受感染细胞的细胞核中发生。我们之前发现了一种名为 RAF-1（RNA 聚合酶激活因子 1）的宿主因子，它可以刺激病毒 RNA 合成。发现 RAF-1 与 Hsp90 相同。在这里，我们检查了 Hsp90 和病毒 RNA 聚合酶亚基的细胞内定位及其分子相互作用。 Hsp90被发现与PB2和PB1相互作用，并且在病毒感染后重新定位到细胞核。我们发现 Hsp90 的核转运发生在单独表达 PB2 的细胞中。 Hsp90 的核转运与病毒 RNA 聚合酶二元复合物（PB1 和 PB2 或 PB1 和 PA）以及单独的 PB2 的核转运平行。 Hsp90 还与二元 RNA 聚合酶复合物 PB1-PB2 相互作用，并且在与 PA 结合后从 PB1-PB2 复合物解离。此外，Hsp90 可以在感染细胞中通过 PA 组装形成三元聚合酶复合物之前形成稳定的 PB1-PB2-Hsp90 复合物。这些结果表明，Hsp90 参与病毒 RNA 聚合酶亚基的组装和核转运，可能在形成成熟的三元聚合酶复合物之前作为聚合酶亚基的分子伴侣。
Transcription and replication of the influenza virus RNA genome occur in the nuclei of infected cells through the viral RNA-dependent RNA polymerase consisting of PB1, PB2, and PA. We previously identified a host factor designated RAF-1 (RNA polymerase activating factor 1) that stimulates viral RNA synthesis. RAF-1 is found to be identical to Hsp90. Here, we examined the intracellular localization of Hsp90 and viral RNA polymerase subunits and their molecular interaction. Hsp90 was found to interact with PB2 and PB1, and it was relocalized to the nucleus upon viral infection. We found that the nuclear transport of Hsp90 occurs in cells expressing PB2 alone. The nuclear transport of Hsp90 was in parallel with that of the viral RNA polymerase binary complexes, either PB1 and PB2 or PB1 and PA, as well as with that of PB2 alone. Hsp90 also interacted with the binary RNA polymerase complex PB1-PB2, and it was dissociated from the PB1-PB2 complex upon its association with PA. Furthermore, Hsp90 could form a stable PB1-PB2-Hsp90 complex prior to the formation of a ternary polymerase complex by the assembly of PA in the infected cells. These results suggest that Hsp90 is involved in the assembly and nuclear transport of viral RNA polymerase subunits, possibly as a molecular chaperone for the polymerase subunits prior to the formation of a mature ternary polymerase complex.