MRC Transition Support Award CDA Edward Hutchinson

这项提议是为了过渡支助继续职业发展奖（CDA）的工作，由于一些意想不到的问题，该奖项被推迟并重新定向。CDA和目前的建议都侧重于流感病毒。这些导致季节性流感，每年在全球造成29万至65万人死亡，是全球主要死亡原因之一。除了每年在人类中引起季节性疾病外，流感病毒还异乎寻常地善于从一个物种跳到另一个物种，因为人类和动物流感病毒如果同时感染同一宿主，它们可以交换基因。流感病毒随时能够进行这种“重组”，加上它们的高突变率，使它们能够引起反复的、有时是毁灭性的大流行。最初的CDA研究集中在传播流感感染的病毒颗粒中的蛋白质上。我们的研究表明，这些因素比我们之前认识到的变化要大得多。宿主细胞和病毒都能强烈地影响病毒颗粒中包含哪些蛋白质以及蛋白质的数量，蛋白质本身可以通过不同的方式进行修饰。我们还发现了一类全新的“隐藏”流感病毒蛋白，并研究了在自然流感病毒感染中产生的病毒颗粒如何在形状上变化，从实验室中通常研究的球形颗粒到非常延伸的细丝。随着我们工作的发展，我们能够检查流感病毒颗粒中更多变异的来源：它们携带的基因，使它们具有传染性的蛋白质以及它们所采用的形状。此过渡支持提案旨在巩固这项工作。工作将从完成在批评性发展评估期间被推迟的三个进展良好的项目开始。第一项研究汇集了多条证据线，以前所未有的细节提供了流感病毒颗粒的图像，并显示了这些微观结构可以在哪里变化。第二幅图显示了随着时间的推移，受感染的细胞如何改变它所释放的病毒颗粒的组成，使它们更具传染性，就像周围的细胞开始增强它们的抗病毒防御一样。第三项研究考察了流感病毒蛋白质的一系列化学修饰，这些修饰可以像一系列开关一样起作用，改变和调节蛋白质的功能。通过这项工作，我们将完成对流感病毒颗粒变化方式的广泛调查，并开发出许多研究这种变化的新工具。然后，我们会问，了解流感病毒颗粒之间的巨大变异范围如何改变我们对感染流感后发生的情况的理解。流感病毒在宿主体内交换基因的能力向我们表明，病毒颗粒在感染过程中可以相互作用，但我们对流感病毒实际工作原理的大部分理解都集中在理解单个病毒颗粒引发感染的过程上。一旦感染在宿主体内进行，我们知道大量高度可变的病毒颗粒会脱落到一个小空间中并相互作用，但我们尚未能够检查这种“病毒微环境”内的相互作用如何形成感染的结果。利用我们开发的工具，我们将首次研究感染我们的单个流感病毒颗粒如何在我们体内迅速产生一群高度可变的病毒颗粒，这些病毒颗粒相互作用，决定了我们的感染过程。除了详细描述正常感染的过程外，这将使我们了解由人类和动物病毒产生的“群”如何聚集在一起，为下一次呼吸道病毒大流行播下种子。

This proposal is for Transition Support to continue the work of a Career Development Award (CDA), which was delayed and redirected in response to a number of unexpected issues. Both the CDA and the current proposal focus on influenza viruses. These cause seasonal influenza, which kills 290 000 - 650 000 people globally each year and is one of the leading global causes of death. As well as causing seasonal illnesses in humans each year, influenza viruses are unusually good at jumping from one species to another, as human and animal influenza viruses can exchange genes if they both infect the same host at the same time. The ready ability of influenza viruses to undergo this 'reassortment,' along with their high mutation rates, enables them to cause repeated and sometimes devastating pandemics.The work in the original CDA focused on proteins in the virus particles that transmit influenza infections. We showed that these were much more variable than was previously appreciated. The host cell and the virus can both strongly influence which proteins are included in virus particles and in what amount, and the proteins themselves can be modified in different ways. We also discovered an entirely new class of 'hidden' influenza virus proteins, and examined how the virus particles produced in natural influenza virus infections can vary in shape, from the spherical particles typically studied in the laboratory to enormously extended filaments. As our work developed, we were able to examine more sources of variation among influenza virus particles: in the genes they carry, in the proteins that make them infectious and the in shapes they adopt.This Transition Support proposal aims to consolidate this work. Work will begin by completing three well-advanced projects that were delayed during the CDA. The first of these draws together multiple lines of evidence to provide a picture of influenza virus particles in unprecedented detail, and showing where these microscopic structures can vary. The second shows how over time an infected cell alters the composition of the virus particles it sheds, making them more infectious just as the surrounding cells start to increase their antiviral defences. The third examines a set of chemical modifications to influenza virus proteins that can act like a series of switches, altering and regulating the proteins' functions.With this work, we will have completed a wide-ranging survey of the ways in which influenza virus particles can vary, and developed many novel tools to study this variation. We will then ask how knowing about the enormous scope for variation among influenza virus particles changes our understanding of what happens when we get infected with influenza. The ability of influenza viruses to swap genes inside their hosts shows us that virus particles can interact during an infection, but most of our understanding of how influenza viruses actually work focusses on understanding the initiation of an infection by one single virus particle. Once an infection is underway in a host, we know that large numbers of highly variable virus particles are shed into a small space and can interact, but we have not yet been able to examine how interactions within this 'viral microenvironment' shape the outcome of an infection. Using the tools we have developed, we will examine for the first time how the single influenza virus particle that infects us, rapidly creates within us a swarm of highly variable virus particles that interact to determine the course of our infection. As well as detailing the course of a normal infection, this will allow us to understand how the 'swarms' created by a human and animal virus could come together to seed the next respiratory virus pandemic.