Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA.
Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA.
J Virol. 2024 Sep 17;98(9):e0086424. doi: 10.1128/jvi.00864-24. Epub 2024 Aug 20.
Novel bat H17N10 and H18N11 influenza A viruses (IAVs) are incapable of reassortment with conventional IAVs during co-infection. To date, the underlying mechanisms that inhibit bat and conventional IAV reassortment remain poorly understood. Herein, we used the bat influenza M gene in the PR8 H1N1 virus genetic background to determine the molecular basis that restricts reassortment of segment 7. Our results showed that NEP and M1 from bat H17N10 and H18N11 can interact with PR8 M1 and NEP, resulting in mediating PR8 viral ribonucleoprotein (vRNP) nuclear export and formation of virus-like particles with single vRNP. Further studies demonstrated that the incompatible packaging signals (PSs) of H17N10 or H18N11 M segment led to the failure to rescue recombinant viruses in the PR8 genetic background. Recombinant PR8 viruses (rPR8psH18M and rPR8psH17M) containing bat influenza M coding region flanked with the PR8 M PSs were rescued but displayed lower replication in contrast to the parental PR8 virus, which is due to a low efficiency of recombinant virus uncoating correlating with the functions of the bat M2. Our studies reveal molecular mechanisms of the M gene that hinder reassortment between bat and conventional IAVs, which will help to understand the biology of novel bat IAVs.
Reassortment is one of the mechanisms in fast evolution of influenza A viruses (IAVs) and responsible for generating pandemic strains. To date, why novel bat IAVs are incapable of reassorting with conventional IAVs remains completely understood. Here, we attempted to rescue recombinant PR8 viruses with M segment from bat IAVs to understand the molecular mechanisms in hindering their reassortment. Results showed that bat influenza NEP and M1 have similar functions as respective counterparts of PR8 to medicating viral ribonucleoprotein nuclear export. Moreover, the incompatible packaging signals of M genes from bat and conventional IAVs and impaired bat M2 functions are the major reasons to hinder their reassortment. Recombinant PR8 viruses with bat influenza M open reading frames were generated but showed attenuation, which correlated with the functions of the bat M2 protein. Our studies provide novel insights into the molecular mechanisms that restrict reassortment between bat and conventional IAVs.
新型蝙蝠 H17N10 和 H18N11 流感 A 病毒（IAV）在共同感染期间不能与传统 IAV 进行重组。迄今为止，抑制蝙蝠和传统 IAV 重组的潜在机制仍知之甚少。在此，我们使用 PR8 H1N1 病毒遗传背景中的蝙蝠流感 M 基因来确定限制 7 节段重组的分子基础。我们的结果表明，来自 H17N10 和 H18N11 的 NEP 和 M1 可以与 PR8 M1 和 NEP 相互作用，从而介导 PR8 病毒核糖核蛋白（vRNP）的核输出并形成具有单个 vRNP 的病毒样颗粒。进一步的研究表明，H17N10 或 H18N11 M 节段的不兼容包装信号（PS）导致在 PR8 遗传背景中无法拯救重组病毒。含有蝙蝠流感 M 编码区侧翼带有 PR8 M PS 的重组 PR8 病毒（rPR8psH18M 和 rPR8psH17M）被拯救，但与亲本 PR8 病毒相比复制能力较低，这是由于与蝙蝠 M2 功能相关的重组病毒脱壳效率较低所致。我们的研究揭示了阻止蝙蝠和传统 IAV 之间重组的 M 基因的分子机制，这将有助于了解新型蝙蝠 IAV 的生物学特性。
重组是流感 A 病毒（IAV）快速进化的机制之一，是产生大流行株的原因。迄今为止，新型蝙蝠 IAV 为何不能与传统 IAV 重组仍完全不清楚。在这里，我们试图用来自蝙蝠 IAV 的 M 节段拯救重组 PR8 病毒，以了解阻止其重组的分子机制。结果表明，蝙蝠流感 NEP 和 M1 具有与 PR8 相应物相似的功能，可介导病毒核糖核蛋白的核输出。此外，蝙蝠和传统 IAV 的 M 基因的不兼容包装信号和受损的蝙蝠 M2 功能是阻止它们重组的主要原因。生成了带有蝙蝠流感 M 开放阅读框的重组 PR8 病毒，但表现出衰减，这与蝙蝠 M2 蛋白的功能有关。我们的研究为限制蝙蝠和传统 IAV 之间重组的分子机制提供了新的见解。
