Nuclear import and export of influenza virus nucleoprotein
Nuclear import and export of influenza virus nucleoprotein
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DOI：
10.1128/jvi.71.12.9690-9700.1997
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发表时间：
1997-12-01
影响因子：
5.4
通讯作者：
Kawaoka, Y
中科院分区：
文献类型：
--
作者：
Neumann, G;Castrucci, MR;Kawaoka, Y
流感病毒核蛋白（NP）穿梭于细胞核和细胞质之间。核定位信号（NLS）在NP的327 ~ 345个氨基酸上被发现（J. Davey et al., Cell 40:667-675, 1985）。然而，一些缺乏该区域的NP突变体仍然定位于细胞核，这表明NP中存在额外的NLS。因此，我们研究了流感病毒A/WSN/33 （H1N1）的NP的核质转运。缺乏38个n端氨基酸的NP缺失构建体，以及缺乏38个n端氨基酸的NP缺失构建体和先前鉴定的NLS，都定位于细胞质和细胞核。一个含有NP的1 ~ 38个氨基酸与LacZ融合的蛋白质的核定位证明，这38个氨基酸具有NLS的功能。在这个区域内，我们发现了两个基本氨基酸，Lys7和Arg8，它们对NP核进口至关重要。导入细胞核后，野生型NP和含有NP氨基酸1 ~ 38的NP- lacz融合构建体均被转运回细胞质中积累。这些数据表明，NP具有内在的结构特征，可以在没有任何其他病毒蛋白的情况下允许核输入、核输出和细胞质积累。此外，尽管可能存在其他NP核输出信号，但核进出口所需的信息位于NP的38个n端氨基酸中。用蛋白激酶C抑制剂处理的细胞增加了核NP的数量，而用磷酸化刺激剂处理的细胞增加了细胞质NP的数量。这些发现提示磷酸化在NP的核质转运中的作用。
Influenza virus nucleoprotein (NP) shuttles between the nucleus and the cytoplasm. A nuclear localization signal (NLS) has been identified in NP at amino acids 327 to 345 (J. Davey et al., Cell 40:667-675, 1985). However, some NP mutants that lack this region still localize to the nucleus, suggesting an additional NLS in NP. We therefore investigated the nucleocytoplasmic transport of NP from influenza virus A/WSN/33 (H1N1). NP deletion constructs lacking the 38 N-terminal amino acids, as well as those lacking the 38 N-terminal amino acids and the previously identified NLS, localized to both the cytoplasm and the nucleus. Nuclear localization of a protein containing amino acids 1 to 38 of NP fused to LacZ proved that these 38 amino acids function as an NLS. Within this region, we identified two basic amino acids, Lys7 and Arg8, that are crucial for NP nuclear import. After being imported into the nucleus, the wild-type NP and the NP-LacZ fusion construct containing amino acids 1 to 38 of NP were both transported back to the cytoplasm, where they accumulated. These data indicate that NP has intrinsic structural features that allow nuclear import, nuclear export, and cytoplasmic accumulation in the absence of any other viral proteins. Further, the information required for nuclear import and export is located in the 38 N-terminal amino acids of NP, although other NP nuclear export signals may exist. Treatment of cells with a protein kinase C inhibitor increased the amounts of nuclear NP, whereas treatment of cells with a phosphorylation stimulator increased the amounts of cytoplasmic NP. These findings suggest a role of phosphorylation in nucleocytoplasmic transport of NP.