甲型流感病毒(IAV)的病毒核糖核蛋白(vRNP)负责病毒RNA在细胞核中的转录和复制,其功能依赖于宿主因素。以前的研究表明,真核翻译延伸因子1δ(eEF1D)可能与RNP亚基相关,但其在IAV复制中的作用尚不清楚。在这里,我们发现eEF1D是IAV复制的抑制剂,因为敲除eEF1D导致病毒产量显著增加.eEF1D与RNP亚基聚合酶酸性蛋白(PA)相互作用,碱性聚合酶1(PB1),聚合酶碱性2(PB2),以及以RNA依赖性方式与核蛋白(NP)。进一步的研究表明,eEF1D阻碍了IAV的NP和PA-PB1异源二聚体的核输入,从而抑制vRNP组装,病毒聚合酶活性,和病毒RNA合成。一起,我们的研究表明,eEF1D通过抑制RNP亚基的核输入来负调节IAV复制,这不仅揭示了eEF1D在IAV复制中的新作用,而且为vRNP蛋白的核导入机制提供了新的见解。重要性甲型流感病毒是流感的主要原因,人类和动物的呼吸道疾病。与大多数其他RNA病毒不同,IAV的转录和复制发生在细胞核中。因此,vRNP必须导入细胞核进行病毒转录和复制,这需要宿主蛋白的参与。然而,核导入过程中涉及的IAV-宿主相互作用机制仍知之甚少.这里,我们确定eEF1D是流感病毒生命周期的新型抑制剂.重要的是,eEF1D损害了NP与导入蛋白α5之间的相互作用以及PB1与RanBP5之间的相互作用,从而阻碍了vRNP的核导入。我们的研究不仅揭示了IAVvRNP核输入的分子机制,而且为抗病毒开发提供了潜在的抗流感靶标。
The viral ribonucleoprotein (
vRNP) of the influenza A virus (IAV) is responsible for the viral RNA transcription and replication in the nucleus, and its functions rely on host factors. Previous studies have indicated that eukaryotic translation elongation factor 1 delta (eEF1D) may associate with RNP subunits, but its roles in IAV replication are unclear. Herein, we showed that eEF1D was an inhibitor of IAV replication because knockout of eEF1D resulted in a significant increase in virus yield. eEF1D interacted with RNP subunits polymerase acidic protein (PA), polymerase basic 1 (PB1), polymerase basic 2 (PB2), and also with nucleoprotein (NP) in an RNA-dependent manner. Further studies revealed that eEF1D impeded the nuclear import of NP and PA-PB1 heterodimer of IAV, thereby suppressing the
vRNP assembly, viral polymerase activity, and viral RNA synthesis. Together, our studies demonstrate eEF1D negatively regulating the IAV replication by inhibition of the nuclear import of RNP subunits, which not only uncovers a novel role of eEF1D in IAV replication but also provides new insights into the mechanisms of nuclear import of
vRNP proteins.IMPORTANCE Influenza A virus is the major cause of influenza, a respiratory disease in humans and animals. Different from most other RNA viruses, the transcription and replication of IAV occur in the cell nucleus. Therefore, the vRNPs must be imported into the nucleus for viral transcription and replication, which requires participation of host proteins. However, the mechanisms of the IAV-host interactions involved in nuclear import remain poorly understood. Here, we identified eEF1D as a novel inhibitor for the influenza virus life cycle. Importantly, eEF1D impaired the interaction between NP and importin α5 and the interaction between PB1 and RanBP5, which impeded the nuclear import of
vRNP. Our studies not only reveal the molecular mechanisms of the nuclear import of IAV
vRNP but also provide potential anti-influenza targets for antiviral development.