A Second CRM1-Dependent Nuclear Export Signal in the Influenza A Virus NS2 Protein Contributes to the Nuclear Export of Viral Ribonucleoproteins
A Second CRM1-Dependent Nuclear Export Signal in the Influenza A Virus NS2 Protein Contributes to the Nuclear Export of Viral Ribonucleoproteins
复制标题
甲型流感病毒 NS2 蛋白中第二个 CRM1 依赖性核输出信号有助于病毒核糖核蛋白的核输出
DOI：
10.1128/jvi.06519-11
复制
发表时间：
2013-01-01
影响因子：
5.4
通讯作者：
Chen, Ze
中科院分区：
文献类型：
--
作者：
Huang, Shengping;Chen, Jingjing;Chen, Ze
甲型流感病毒NS 2蛋白，又称核输出蛋白（NEP），是病毒核糖核蛋白向核输出的关键蛋白。然而，在这一过程中NEP介导的分子机制仍然不完全清楚。本研究发现NEP中存在一个富含亮氨酸的核输出信号（NES 2），位于N-末端结构域的N2螺旋。NES 2被证明是可转移的内斯，其核输出活性依赖于核输出受体染色体区域维持1（CRM 1）介导的途径。NEP和CRM 1之间的相互作用是协调调节的内斯（NES 1），现在新的NES 2。NES 1的缺失增强了NEP和CRM 1之间的相互作用，NES 1和NES 2基序的缺失完全消除了这种相互作用。此外，在哺乳动物双杂交系统中，NES 2与CRM 1相互作用。通过反向遗传学产生的含有NES 2改变的突变病毒表现出病毒生长减少和病毒核糖核蛋白（vRNP）核输出延迟。NES 2基序在甲型和B型流感病毒中高度保守。结果表明，富含亮氨酸的NES 2参与vRNP的核输出，并有助于理解流感病毒vRNP的核质转运。
ABSTRACT Influenza A virus NS2 protein, also called nuclear export protein (NEP), is crucial for the nuclear export of viral ribonucleoproteins. However, the molecular mechanisms of NEP mediation in this process remain incompletely understood. A leucine-rich nuclear export signal (NES2) in NEP, located at the predicted N2 helix of the N-terminal domain, was identified in the present study. NES2 was demonstrated to be a transferable NES, with its nuclear export activity depending on the nuclear export receptor chromosome region maintenance 1 (CRM1)-mediated pathway. The interaction between NEP and CRM1 is coordinately regulated by both the previously reported NES (NES1) and now the new NES2. Deletion of the NES1 enhances the interaction between NEP and CRM1, and deletion of the NES1 and NES2 motifs completely abolishes this interaction. Moreover, NES2 interacts with CRM1 in the mammalian two-hybrid system. Mutant viruses containing NES2 alterations generated by reversed genetics exhibit reduced viral growth and delay in the nuclear export of viral ribonucleoproteins (vRNPs). The NES2 motif is highly conserved in the influenza A and B viruses. The results demonstrate that leucine-rich NES2 is involved in the nuclear export of vRNPs and contributes to the understanding of nucleocytoplasmic transport of influenza virus vRNPs.