Cellular splicing factor RAF-2p48/NPI-5/BAT1/UAP56 interacts with the influenza virus nucleoprotein and enhances viral RNA synthesis
Cellular splicing factor RAF-2p48/NPI-5/BAT1/UAP56 interacts with the influenza virus nucleoprotein and enhances viral RNA synthesis
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DOI：
10.1128/jvi.75.4.1899-1908.2001
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发表时间：
2001-02-01
影响因子：
5.4
通讯作者：
Nagata, K
中科院分区：
文献类型：
--
作者：
Momose, F;Basler, CF;Nagata, K
此前的生化数据证实了一种宿主细胞组分，命名为RAF-2，它能刺激流感病毒RNA的合成。一个48 kDa的多肽(RAF-2P48)是一种细胞剪接因子，属于以前被命名为BAT1(也称为UAP56)的RNA依赖ATPase死盒家族，现在被认为是RAF-2刺激活性所必需的。此外，在酵母双杂交筛选的哺乳动物文库中，RAF-2p48被独立地鉴定为流感病毒核蛋白(NP)相互作用蛋白NPI-5。在体外，RAP-2p48与游离NP相互作用，但不与结合在RNA上的NP相互作用，加入游离RNA后，RAF-2p48-NP复合体解离。此外，RAF-2p48促进了NP-RNA复合体的形成，这些复合体可能作为病毒RNA聚合酶的模板。在体外结合试验和酵母双杂交系统中，RAF-2p48都被证明与NP的氨基末端区域结合，这是RNA结合所必需的区域。综上所述，这些观察表明RAF-2p48促进了NP-RNA的相互作用，从而导致流感病毒RNA合成的增强。
Previous biochemical data identified a host cell fraction, designated RAF-2, which stimulated influenza virus RNA synthesis. A 48-kDa polypeptide (RAF-2p48), a cellular splicing factor belonging to the DEAD-box family of RNA-dependent ATPases previously designated BAT1 (also UAP56), has now been identified as essential for RAF-2 stimulatory activity. Additionally, RAF-2p48 was independently identified as an influenza virus nucleoprotein (NP)-interacting protein, NPI-5, in a yeast two-hybrid screen of a mammalian cDNA library. In vitro, RAP-2p48 interacted with free NP but not with NP bound to RNA, and the RAF-2p48-NP complex was dissociated following addition of free RNA. Furthermore, RAF-2p48 facilitated formation of the NP-RNA complexes that likely serve as templates for the viral RNA polymerase. RAF-2p48 was shown, in both in vitro binding assays and the yeast two-hybrid system, to bind to the amino-terminal region of NP, a domain essential for RNA binding. Together, these observations suggest that RAF-2p48 facilitates NP-RNA interaction, thus leading to enhanced influenza virus RNA synthesis.