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Abstract：
Influenza A viruses (IAVs) possess a segmented genome consisting of eight viral RNAs (vRNAs) associated with multiple copies of viral nucleoprotein (NP) and a viral polymerase complex. Despite the crucial role of RNA structure in IAV replication, the impact of NP binding on vRNA structure is not well understood. In this study, we employed SHAPE chemical probing to compare the structure of NS and M vRNAs of WSN IAV in various states: before the addition of NP, in complex with NP, and after the removal of NP. Comparison of the RNA structures before the addition of NP and after its removal reveals that NP, while introducing limited changes, remodels local structures in both vRNAs and long-range interactions in the NS vRNA, suggesting a potentially biologically relevant RNA chaperone activity. In contrast, NP significantly alters the structure of vRNAs in vRNA/NP complexes, though incorporating experimental data into RNA secondary structure prediction proved challenging. Finally, our results suggest that NP not only binds single-stranded RNA but also helices with interruptions, such as bulges or small internal loops, with a preference for G-poor and C/U-rich regions.
摘要：
甲型流感病毒(IAV)具有由与病毒核蛋白(NP)的多个拷贝相关的八个病毒RNA(vRNA)和病毒聚合酶复合物组成的分段基因组。尽管RNA结构在IAV复制中起着至关重要的作用，NP结合对vRNA结构的影响尚不清楚。在这项研究中,我们使用SHAPE化学探测来比较WSNIAV的NS和MvRNA在各种状态下的结构：在添加NP之前，在复杂的NP，然后去除NP。添加NP之前和去除后的RNA结构的比较表明，NP，在引入有限变化的同时，重塑vRNA中的局部结构和NSvRNA中的长程相互作用，提示潜在的生物学相关的RNA伴侣活性。相比之下,NP显著改变vRNA/NP复合物中vRNA的结构，尽管将实验数据纳入RNA二级结构预测被证明具有挑战性。最后,我们的结果表明，NP不仅结合单链RNA，而且与中断的螺旋，如凸起或小的内部回路，偏好G贫和富C/U地区。
