Interaction of the influenza virus nucleoprotein with the cellular CRM1-mediated nuclear export pathway
Interaction of the influenza virus nucleoprotein with the cellular CRM1-mediated nuclear export pathway
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DOI：
10.1128/jvi.75.1.408-419.2001
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发表时间：
2001-01-01
影响因子：
5.4
通讯作者：
Digard, P
中科院分区：
文献类型：
--
作者：
Elton, D;Simpson-Holley, M;Digard, P
流感病毒转录发生在感染细胞的细胞核中，在那里病毒基因组rna与核蛋白（NP）复合物形成核糖核蛋白（RNP）结构。在组装成子代病毒粒子之前，这些RNPs离开细胞核并在细胞质中积累。负责RNP输出的机制仅部分了解，但已提出涉及病毒M1和NS2多肽。我们发现药物leptomycin B （LMB）特异性灭活细胞CRM1多肽，在病毒感染的细胞中引起NP的核保留，表明CRM1核输出途径在RNP输出中起作用。然而，在M1或NS2的细胞分布中没有发现任何变化，即使在合成NS2数量大大减少的突变病毒的情况下也是如此。此外，NP在感染后早期分布在感染细胞的细胞核中，但在LMB治疗后期保留在细胞核中时，会重新分布到核质周围。药物治疗后，M1和NS2的核分布未见明显变化。与NP、M1和NS2在感染细胞中的行为类似，LMB对分离表达每种多肽的细胞进行处理，会导致NP的核保留，而M1和NS2的核保留不会发生。相反，CRM1的过表达增加了NP的细胞质积累，但对M1或NS2的分布影响不大。与此一致的是，体外NP结合的CRM1。总的来说，这些数据提出了RNP输出是由NP和细胞CRM1输出途径之间的直接相互作用介导的可能性。
Influenza virus transcription occurs in the nuclei of infected cells, where the viral genomic RNAs are complexed with a nucleoprotein (NP) to form ribonucleoprotein (RNP) structures. Prior to assembly into progeny virions, these RNPs exit the nucleus and accumulate in the cytoplasm. The mechanisms responsible for RNP export are only partially understood but have been proposed to involve the viral M1 and NS2 polypeptides. We found that the drug leptomycin B (LMB), which specifically inactivates the cellular CRM1 polypeptide, caused nuclear retention of NP in virus-infected cells, indicating a role for the CRM1 nuclear export pathway in RNP egress. However, no alteration was seen in the cellular distribution of M1 or NS2, even in the case of a mutant virus which synthesizes greatly reduced amounts of NS2. Furthermore, NP was distributed throughout the nuclei of infected cells at early times postinfection but, when retained in the nucleus at late times by LMB treatment, was redistributed to the periphery of the nucleoplasm. No such change was seen in the nuclear distribution of M1 or NS2 after drug treatment. Similar to the behavior of NP, M1 and NS2 in infected cells, LMB treatment of cells expressing each polypeptide in isolation caused nuclear retention of NP but not M1 or NS2. Conversely, overexpression of CRM1 caused increased cytoplasmic accumulation of NP but had little effect on M1 or NS2 distribution. Consistent with this, NP bound CRM1 in vitro. Overall, these data raise the possibility that RNP export is mediated by a direct interaction between NP and the cellular CRM1 export pathway.