Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO, USA; Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA.
Center for Influenza and Emerging Infectious Diseases, University of Missouri, Columbia, MO, USA; Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.
Virology. 2021 Jul;559:145-155. doi: 10.1016/j.virol.2021.04.001. Epub 2021 Apr 9.
PB1 functions as the catalytic subunit of influenza virus RNA polymerase complex and plays an essential role in viral RNA transcription and replication. To determine plasticity in the PB1 enzymatic site and map catalytically important residues, 658 mutants were constructed, each with one to seven mutations in the enzymatic site of PB1. The polymerase activities of these mutants were quantified using a minigenome assay, and polymerase activity-associated residues were identified using sparse learning. Results showed that polymerase activities are affected by the residues not only within the conserved motifs, but also across the inter-motif regions of PB1, and the latter are primarily located at the base of the palm domain, a region that is conserved in avian PB1 but with high sequence diversity in swine PB1. Our results suggest that mutations outside the PB1 conserved motifs may affect RNA replication and could be associated with influenza virus host adaptation.
PB1 作为流感病毒 RNA 聚合酶复合物的催化亚基，在病毒 RNA 转录和复制中发挥着重要作用。为了确定 PB1 酶活性位点的可塑性并绘制催化关键残基，构建了 658 个突变体，每个突变体在 PB1 的酶活性位点有一个到七个突变。使用小基因检测法来定量这些突变体的聚合酶活性，并使用稀疏学习来鉴定与聚合酶活性相关的残基。结果表明，聚合酶活性不仅受保守基序内的残基影响，而且受 PB1 跨基序区域的残基影响，后者主要位于手掌结构域的底部，该区域在禽 PB1 中保守，但在猪 PB1 中具有高度的序列多样性。我们的研究结果表明，PB1 保守基序之外的突变可能影响 RNA 复制，并且可能与流感病毒宿主适应性相关。
