Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada.
Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada.
Virology. 2019 Oct;536:91-100. doi: 10.1016/j.virol.2019.08.002. Epub 2019 Aug 2.
Initiation of influenza A virus (IAV) transcription depends on RNA primers derived from host RNAs. During this process, some primers are elongated by a few nucleotides, realigned on the viral RNA templates (vRNA), and then used to initiate another round of transcription. Here, we used information on the host primers used by four IAV strains and four mini-replicons to investigate the characteristics of primer undergoing priming and realignment. We report that primers are biased towards this mechanism on the basis of length and RNA duplex stability with the vRNA templates. Priming and realignment results in primers three nucleotides longer, ending in a nucleotide sequence able to base pair with the 3' end of the vRNA template. By acting on primers based on length and sequence compatibility with the 3' end of the vRNA, priming and realignment rescues suboptimal primers, converting them into ones that can efficiently initiate transcription.
流感病毒 A（IAV）转录的起始依赖于宿主 RNA 衍生的 RNA 引物。在此过程中，一些引物通过几个核苷酸延伸，在病毒 RNA 模板（vRNA）上重新排列，然后用于启动另一轮转录。在这里，我们使用了四种 IAV 株和四种迷你复制子中宿主引物的信息，来研究引物引发和重新排列的特征。我们报告说，基于引物与 vRNA 模板的长度和 RNA 双链体稳定性，引物偏向于这种机制。引发和重新排列导致引物延长三个核苷酸，以能够与 vRNA 模板的 3' 端配对的核苷酸序列结束。通过作用于基于长度和与 vRNA 3' 端序列兼容性的引物，引发和重新排列可以挽救次优引物，将其转化为能够有效启动转录的引物。
