Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA.
J Med Virol. 2023 Jul;95(7):e28896. doi: 10.1002/jmv.28896.
The genome of influenza A viruses (IAV) consists of eight negative-sense RNA segments that are coated by viral nucleoprotein (NP). Until recently, it was assumed that NP binds viral genomic RNA (vRNA) uniformly along the entire segment. However, genome-wide studies have revised the original model in that NP instead binds preferentially to certain regions of vRNA, while others are depleted for NP binding. Even strains with high sequence similarity exhibit distinct NP-binding profiles. Thus, it remains unknown how NP-binding specificity to vRNA is established. Here we introduced nucleotide changes to vRNA to examine whether primary sequence can affect NP binding. Our findings demonstrate that NP binding is indeed susceptible to sequence alterations, as NP peaks can be lost or appear de novo at mutated sites. Unexpectedly, nucleotide changes not only affect NP binding locally at the site of mutation, but also impact NP binding at distal regions that have not been modified. Taken together, our results suggest that NP binding is not regulated by primary sequence alone, but that a network formed by multiple segments governs the deposition of NP on vRNA.
甲型流感病毒（IAV）的基因组由 8 个负义 RNA 片段组成，这些片段被病毒核蛋白（NP）包裹。直到最近，人们一直认为 NP 均匀地结合在整条 RNA 链上。然而，全基因组研究修正了最初的模型，即 NP 优先结合 vRNA 的某些区域，而其他区域则缺乏 NP 结合。即使是具有高度序列相似性的毒株，其 NP 结合谱也存在明显差异。因此，目前尚不清楚 NP 结合 vRNA 的特异性是如何建立的。在这里，我们引入了 vRNA 的核苷酸变化，以研究核苷酸序列是否可以影响 NP 结合。研究结果表明，NP 结合确实容易受到序列改变的影响，因为 NP 峰可以在突变位点丢失或新出现。出乎意料的是，核苷酸改变不仅会影响突变位点的 NP 结合，还会影响未修饰的远端区域的 NP 结合。总的来说，我们的研究结果表明，NP 结合不仅仅受一级序列的调控，而是由多个片段形成的网络来控制 NP 在 vRNA 上的沉积。
