The structure of the influenza A virus genome

Influenza A viruses (IAVs) constitute a major threat to human health. The IAV genome consists of eight single-stranded viral RNA segments contained in separate viral ribonucleoprotein (vRNP) complexes that are packaged together into a single virus particle. The structure of viral RNA is believed to play a role in assembling the different vRNPs into budding virions1,2,3,4,5,6,7,8 and in directing reassortment between IAVs9. Reassortment between established human IAVs and IAVs harboured in the animal reservoir can lead to the emergence of pandemic influenza strains to which there is little pre-existing immunity in the human population10,11. While previous studies have revealed the overall organization of the proteins within vRNPs, characterization of viral RNA structure using conventional structural methods is hampered by limited resolution and an inability to resolve dynamic components12,13. Here, we employ multiple high-throughput sequencing approaches to generate a global high-resolution structure of the IAV genome. We show that different IAV genome segments acquire distinct RNA conformations and form both intra- and intersegment RNA interactions inside influenza virions. We use our detailed map of IAV genome structure to provide direct evidence for how intersegment RNA interactions drive vRNP cosegregation during reassortment between different IAV strains. The work presented here is a roadmap both for the development of improved vaccine strains and for the creation of a framework to ‘risk assess’ reassortment potential to better predict the emergence of new pandemic influenza strains

Understanding Influenza

Influenza, a serious illness of humans and domesticated animals, has been studied intensively for many years. It therefore provides an example of how much we can learn from detailed studies of an infectious disease and of how even the most intensive scientific research leaves further questions to answer. This introduction is written for researchers who have become interested in one of these unanswered questions, but who may not have previously worked on influenza. To investigate these questions, researchers must not only have a firm grasp of relevant methods and protocols; they must also be familiar with the basic details of our current understanding of influenza. This article therefore briefly covers the burden of disease that has driven influenza research, summarizes how our thinking about influenza has evolved over time, and sets out key features of influenza viruses by discussing how we classify them and what we understand of their replication. It does not aim to be comprehensive, as any researcher will read deeply into the specific areas that have grasped their interest. Instead, it aims to provide a general summary of how we came to think about influenza in the way we do now, in the hope that the reader’s own research will help us to understand it better

The structure of the influenza A virus genome

Influenza A viruses (IAVs) constitute a major threat to human health. The IAV genome consists of eight single-stranded viral RNA segments contained in separate viral ribonucleoprotein (vRNP) complexes that are packaged together into a single virus particle. The structure of viral RNA is believed to play a role in assembling the different vRNPs into budding virions1,2,3,4,5,6,7,8 and in directing reassortment between IAVs9. Reassortment between established human IAVs and IAVs harboured in the animal reservoir can lead to the emergence of pandemic influenza strains to which there is little pre-existing immunity in the human population10,11. While previous studies have revealed the overall organization of the proteins within vRNPs, characterization of viral RNA structure using conventional structural methods is hampered by limited resolution and an inability to resolve dynamic components12,13. Here, we employ multiple high-throughput sequencing approaches to generate a global high-resolution structure of the IAV genome. We show that different IAV genome segments acquire distinct RNA conformations and form both intra- and intersegment RNA interactions inside influenza virions. We use our detailed map of IAV genome structure to provide direct evidence for how intersegment RNA interactions drive vRNP cosegregation during reassortment between different IAV strains. The work presented here is a roadmap both for the development of improved vaccine strains and for the creation of a framework to ‘risk assess’ reassortment potential to better predict the emergence of new pandemic influenza strains

Symplocos prunifolia Sieb. et Zucc.

原著和名: クロバヒ科名: ハイノキ科 = Symplocaceae採集地: 千葉県 清澄山 (安房 清澄山)採集日: 1962/5/13採集者: 萩庭丈壽整理番号: JH037195国立科学博物館整理番号: TNS-VS-98719

The structure of the influenza A virus genome

Influenza A viruses (IAVs) constitute a major threat to human health. The IAV genome consists of eight single-stranded viral RNA segments contained in separate viral ribonucleoprotein (vRNP) complexes that are packaged together into a single virus particle. The structure of viral RNA is believed to play a role in assembling the different vRNPs into budding virions1-8 and in directing reassortment between IAVs9. Reassortment between established human IAVs and IAVs harboured in the animal reservoir can lead to the emergence of pandemic influenza strains to which there is little pre-existing immunity in the human population10,11. While previous studies have revealed the overall organization of the proteins within vRNPs, characterization of viral RNA structure using conventional structural methods is hampered by limited resolution and an inability to resolve dynamic components12,13. Here, we employ multiple high-throughput sequencing approaches to generate a global high-resolution structure of the IAV genome. We show that different IAV genome segments acquire distinct RNA conformations and form both intra- and intersegment RNA interactions inside influenza virions. We use our detailed map of IAV genome structure to provide direct evidence for how intersegment RNA interactions drive vRNP cosegregation during reassortment between different IAV strains. The work presented here is a roadmap both for the development of improved vaccine strains and for the creation of a framework to 'risk assess' reassortment potential to better predict the emergence of new pandemic influenza strains

Visualization of lncRNA and mRNA Structure Models Within the Integrative Genomics Viewer

Every class of RNA forms base-paired structures that impact biological functions. Chemical probing of RNA structure, especially with the advent of strategies such as SHAPE-MaP, vastly expands the scale and quantitative accuracy over which RNA structure can be examined. These methods have enabled large-scale structural studies of mRNAs and lncRNAs, but the length and complexity of these RNAs makes interpretation of the data challenging. We have created modules available through the open-source Integrative Genomics Viewer (IGV) for straightforward visualization of RNA structures and associated and complementary experimental data. Here we present detailed and stepwise strategies for exploring and visualizing complex RNA structures in IGV. Individuals can use these instructions and supplied sample data to become adept at using IGV to visualize RNA structure models in conjunction with useful allied information