Nuclear export factor CRM1 interacts with nonstructural proteins NS2 from parvovirus minute virus of mice
Nuclear export factor CRM1 interacts with nonstructural proteins NS2 from parvovirus minute virus of mice
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DOI：
10.1128/jvi.73.9.7769-7779.1999
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发表时间：
1999-09-01
影响因子：
5.4
通讯作者：
Salomé, N
中科院分区：
文献类型：
--
作者：
Bodendorf, U;Cziepluch, C;Salomé, N
已知自主细小病毒的非结构 NS2 蛋白以宿主细胞依赖性方式发挥作用，并在病毒 DNA 复制、病毒 mRNA 的有效翻译和/或衣壳化中发挥作用。然而，它们在细小病毒生命周期中的确切功能仍然不清楚。我们在此报告了与小鼠细小病毒（MVM）和大鼠的 NS2 蛋白以及人类 CRM1 蛋白的小鼠同源物的相互作用的特征，CRM1 蛋白是最近被确定为重要核输出因子的 importin-beta 家族的成员。使用双杂交系统，我们可以检测大鼠 CRM1 的羧基末端区域与 NS2 的三种亚型（P [或主要]、Y [或次要]和 L [或稀有]）之间的相互作用。使用小鼠和大鼠细胞系的提取物进行免疫共沉淀实验，进一步证明 NS2 蛋白与全长 CRM1 相互作用。我们的数据显示 CRM1 优先结合 NS2 的非磷酸化亚型。此外，我们观察到用瘦霉素 B（一种特异性抑制 CRM1 依赖性核输出途径的药物）处理 MVM 感染的细胞，会导致 NS2 蛋白在细胞核中急剧积累。 NS2 与 CRM1 的相互作用以及瘦霉素 B 处理后的核积累都强烈表明，这些非结构病毒蛋白通过 CRM1 介导的核输出途径主动从受感染细胞的细胞核中输出。
The nonstructural NS2 proteins of autonomous parvoviruses are known to act in a host cell-dependent manner and to play a role in viral DNA replication, efficient translation of viral mRNA, and/or encapsidation. Their exact function during the parvovirus life cycle remains, however, still obscure. We report here the characterization of the interaction with the NS2 proteins from the parvovirus minute virus of mice (MVM) and rat as well as mouse homologues of the human CRM1 protein, a member of the importin-beta family recently identified as an essential nuclear export factor. Using the two-hybrid system, we could detect the interaction between the carboxy-terminal region of rat CRM1 and each of the three isoforms of NS2 (P [or major], Y [or minor], and L [or rare]). NS2 proteins were further shown to interact with the full-length CRM1 by coimmunoprecipitation experiments using extracts from both mouse and rat cell lines. Our data show that CRM1 preferentially binds to the nonphosphorylated isoforms of NS2. Moreover, we observed that the treatment of MVM-infected cells with leptomycin B, a drug that specifically inhibits the CRM1-dependent nuclear export pathway, leads to a drastic accumulation of NS2 proteins in the nucleus. Both NS2 interaction with CRM1 and nuclear accumulation upon leptomycin B treatment strongly suggest that these nonstructural viral proteins are actively exported out of the nuclei of infected cells via a CRM1-mediated nuclear export pathway.