Genomic RNA control of HIV viral assembly and export

尽管现有治疗艾滋病毒的药物在多样性和有效性方面取得了重大进展，但艾滋病毒仍然是全世界疾病和死亡的主要原因。HIV是一种RNA病毒，它将其RNA基因组的两个拷贝装入每个病毒颗粒中。这是一个病毒通过主要结构病毒蛋白Gag的结构域和病毒全长基因组RNA的区域之间的非常特定的相互作用来实现的过程，病毒全长基因组RNA已经折叠形成了一个独特的可识别的三维形状。RNA的折叠依赖于病毒RNA的核苷酸序列所以这种特殊的结构只能由HIV基因组形成。关于病毒在离开细胞时如何自我组装和捕获其遗传物质的许多细节仍然不完全清楚。正因为如此，它是生命周期的一部分，是目前尚未开发的治疗靶点。我们知道许多细胞和病毒蛋白参与其中，但它们如何与RNA基因组相互作用仍未完全阐明。我们现在已经发现证据表明，该病毒利用其遗传物质RNA的存在作为一种质量控制措施来调节病毒输出的效率。只有含有RNA基因组的病毒才能经历正确的成熟步骤，并以最佳的效率从感染细胞中发芽。这对病毒很重要，因为一个没有捕获任何遗传物质的粒子是不具有传染性的。我们的数据表明，RNA的存在控制着病毒如何组装，以及病毒如何成熟为感染性颗粒。RNA的存在似乎也确保了病毒和细胞蛋白质之间正确的相互作用，这些蛋白质用于促进出芽。我们对病毒出芽过程中涉及的蛋白质因素了解很多，但直到现在，RNA成分控制这一过程的方式在很大程度上被忽视了。我们发表的初步数据表明，病毒RNA与病毒和细胞蛋白之间存在重要的相互作用，可以作为抑制病毒复制的新方法。我们将分析这一过程，以建立和表征病毒RNA与细胞蛋白的特定相互作用，其中一些我们已经确定。我们将使用最现代的技术来识别RNA/蛋白质相互作用，包括我们自己开发的一些技术。我们还将使用超分辨率显微镜和晶体学来可视化病毒出芽复合体的核心成分以及不同成分如何相互作用。通过充分了解这些过程，我们将能够确定药物干预的新潜在目标。我们已经利用了这一过程的一部分（包括纯病毒成分）作为药物靶点，这是与葛兰素史克公司正在进行的合作的主题。对涉及细胞蛋白质的过程的更详细的了解将提供病毒难以逃脱的新靶点，并将有效地增加治疗这种感染的现有药物的药库。

HIV remains a major cause of illness and death worldwide despite major advances in the diversity and efficaciousness of available drugs to treat the virus. HIV is an RNA virus which encapsidates two copies of its RNA genome into each virus particle. This is a process which the virus achieves by a very specific interaction between domains of the major structural viral protein Gag and a region of the viral full length genomic RNA which has folded up to form a uniquely recognisable three dimensional shape. The folding up of the RNA is dependent on the nucleotide sequence of the virus RNA so this particular structure can only be formed by the HIV genome. Many of the details about how the virus assembles itself and captures its genetic material as it leaves the cell are still incompletely understood. Because of this it is a part of the lifecycle which is a currently unexploited therapeutic target. We know many of the cellular and viral proteins involved but how they interact with the RNA genome is still not fully elucidated. We have now found evidence that the virus uses the presence of its genetic material, RNA, as a quality control measure to regulate the efficiency of virus export. Only viruses which contain the RNA genome undergo the correct maturation steps and bud with optimal efficiency from the infected cell. This is important for the virus since a particle that budded out without capturing any genetic material would not be infectious. Our data show that the presence of the RNA controls how the virus assembles and how the virus matures into an infectious particle. The presence of the RNA also seems to ensure correct interactions between viral and cellular proteins which are used to facilitate budding. Much is known about the protein factors involved in virus budding but until now the way the RNA component controls the process has largely been ignored. Our published and preliminary data indicates that there are important interactions between the viral RNA and viral and cellular proteins that can be exploited as new ways to inhibit virus replication. We will analyse this process to establish and characterise specific interactions of the viral RNA with cellular proteins, some of which we have already identified. We will use the most modern techniques for identifying RNA/protein interactions, including some that we have developed ourselves. We will also use super resolution microscopy and crystallography to visualise the core components of a budding complex of the virus and how the different components interact. By understanding these processes fully we will be able to identify new potential targets for drug intervention. We have already exploited part of this process (involving purely viral components) as a drug target and this is the subject of an ongoing collaboration with Glaxo SmithKline. More detailed knowledge of processes involving cellular proteins will provide new targets which the virus will have difficulty escaping from and which will add usefully to the armamentarium of drugs available to treat this infection.