Exploiting the power of heterologous expression in plants to discover new virus structure.

利用植物异源表达的力量来发现新的病毒结构。

基本信息

批准号：
BB/R00160X/1
负责人：
Neil Ranson
金额：
$ 62.99万
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FR00160X%2F1
关键词：
Exploiting power heterologous expression plants

项目摘要

For a virus to be able to spread from one organism to another, it is absolutely essential that a protective protein (and sometimes membrane-containing) capsid is assembled to protect its genetic material (genome) from the harsh external environment. Typically, the protein capsid is formed from one (or a few) type of coat protein that assembles to form a highly symmetric container into which the genome is packaged. These capsids are characteristic of the virus: each virus has a particular size, shape and configuration that uniquely identifies it. A large number of 3D structures have been determined for virus capsids, and these structures have helped revolutionise research into viruses. Structural information enables a myriad of experiments, including the design of mutant versions of the viruses to help understand their basic biology, informing the design of new molecules that have antiviral properties and are thus potential anti-viral medicines, and helping to validate the design and efficacy of new vaccines. However, despite these enormous strides, large holes exist in our structural understanding of the viruses in nature. A great many different types of viruses, including viruses that are devastating pathogens of crops around the world, and a thus are a major source of food insecurity in the developing world, currently have no structures. In part this is because many viruses, especially those that are extremely toxic to plants, are exquisitely difficult to propagate in the amounts required for structural studies. We are now in a position to remedy this problem. Using cryo-electron microscopy, a technique in structural biology that is now capable of generating structures for viruses at atomic resolution using relatively small amounts of virus (at the University of Leeds), and new capabilities to express virus proteins in plants (at the John Innes Centre in Norwich), we have shown that virus-like particles that are identical to the authentic virus can be produced, and their 3D structures can be relatively rapidly determined. We will now use these techniques to fill in some of the gaps in our structural knowledge of viruses present in Nature. We will start with the Luteoviridae, a family of viruses that infect plants, and are commercially important pathogens of cereals and potatoes. We have already determined a preliminary structure for one: potato leaf roll virus, showing that our approach is highly likely to yield rapid results. We will improve our existing structure and solve the structure of other important family members, before beginning to work on more challenging viruses (with more complicated capsids). These will include a large number of different families of plant viruses, which again include important pathogens that devastate food and commercial crops across the developing world (e.g. rice tungro spherical virus, that is implicated in rice crop losses of >$1.5 billion p.a.). They will also include human pathogens.Clearly a greater understanding of the structure that viruses assemble to protect their genomes, and of processes essential for virus spread would be of huge significance to our ability to combat the diseases these viruses cause. Such understanding might help to develop virus particles that can act vaccines, or as vehicles for the delivery of molcules to cells for a variety of medical applications. As a routine part of our work, we will generate a novel protein-based binding reagent that can specifically recognise the virus in question. These molecules, called 'Adhirons' are functionally analogous to antibodies, and will be an invaluable resource for researchers interested in the virus in question, potentially allowing for example the rapid diagnosis of infection in a simple, in-field testing device, or the purification of small amounts of authentic virus from infected tissues for future research. The knowledge gained from these studies would therefore also aid applications in biotechnology.

对于病毒能够从一种生物体传播到另一种生物体来说，组装保护性蛋白质（有时是含膜）衣壳以保护其遗传物质（基因组）免受恶劣的外部环境的影响是绝对必要的。通常，蛋白质衣壳由一种（或几种）类型的外壳蛋白形成，该外壳蛋白组装形成高度对称的容器，基因组被包装在其中。这些衣壳是病毒的特征：每种病毒都有特定的大小、形状和结构，可以唯一地识别它。病毒衣壳的大量 3D 结构已被确定，这些结构有助于彻底改变病毒研究。结构信息使得大量的实验成为可能，包括设计病毒的突变版本以帮助了解其基本生物学，为具有抗病毒特性并因此成为潜在抗病毒药物的新分子的设计提供信息，并帮助验证设计和新疫苗的功效。然而，尽管取得了这些巨大的进步，我们对自然界病毒的结构理解仍然存在很大的漏洞。许多不同类型的病毒，包括对世界各地农作物具有毁灭性病原体的病毒，因此是发展中国家粮食不安全的主要根源，目前还没有结构。部分原因是许多病毒，尤其是那些对植物剧毒的病毒，很难以结构研究所需的数量繁殖。我们现在可以解决这个问题。使用冷冻电子显微镜，一种结构生物学技术，现在能够使用相对少量的病毒（在利兹大学）以原子分辨率生成病毒结构，以及在植物中表达病毒蛋白的新能力（在约翰在诺维奇的英尼斯中心），我们已经证明可以生产与真实病毒相同的病毒样颗粒，并且可以相对快速地确定它们的 3D 结构。我们现在将使用这些技术来填补我们对自然界中存在的病毒的结构知识的一些空白。我们将从黄体病毒科开始，黄体病毒科是感染植物的病毒家族，是谷物和马铃薯的商业重要病原体。我们已经确定了其中一种病毒的初步结构：马铃薯卷叶病毒，这表明我们的方法极有可能快速产生结果。在开始研究更具挑战性的病毒（具有更复杂的衣壳）之前，我们将改进现有的结构并解决其他重要家族成员的结构。其中包括大量不同的植物病毒家族，其中又包括毁坏发展中国家粮食和经济作物的重要病原体（例如水稻东格罗球形病毒，每年造成水稻作物损失超过 15 亿美元）。它们还包括人类病原体。显然，更好地了解病毒为保护其基因组而组装的结构以及病毒传播所必需的过程对于我们对抗这些病毒引起的疾病的能力具有重要意义。这种理解可能有助于开发可以发挥疫苗作用的病毒颗粒，或者作为将分子递送到细胞的载体以用于各种医疗应用。作为我们工作的常规部分，我们将生成一种新型的基于蛋白质的结合试剂，可以特异性识别相关病毒。这些被称为“Adhirons”的分子在功能上类似于抗体，对于对相关病毒感兴趣的研究人员来说将是宝贵的资源，例如可能允许在简单的现场测试设备中快速诊断感染，或纯化病毒从受感染组织中提取少量真实病毒以供未来研究。因此，从这些研究中获得的知识也将有助于生物技术的应用。