Structure and function of the Bovine Viral Diarrhea Virus 3' UTR during the virus life cycle.

牛病毒性腹泻病毒 3 UTR 在病毒生命周期中的结构和功能。

• 批准号: RGPIN-2018-06335
• 负责人: Wilson, Joyce
• 金额: $ 7.29万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=761050
• 关键词: Structure; function; Bovine; Viral; Diarrhea

Bovine viral diarrhea virus (BVDV) is an important pathogen to the cattle industry, through both acute and persistent infections (PI). Acute infections decrease reproduction in both male and females cattle, and PI calves are sources of infection. PI calves result from in utero BVDV infection of the fetus in acutely infected pregnant females. Control of BVDV involves identification and culling of PI calves, and vaccination. However, vaccination with modified live vaccines can lead to the birth of PI calves if vaccines are accidently given to pregnant females. BVDV has a + stranded RNA genome and its replication is regulated by the structure of the RNA genome and protein that bind to it. In particular, the 5' and 3' end regions, the un-translated regions (UTRs), contain sequences and structures that regulate virus translation and replication. In addition, the UTRs of a few viruses, hepatitis C virus (HCV) and BVDV, also bind miRNAs that promote the virus life-cycle, possibly by modulating the functions of the RNA to which they bind and altering RNA structures and/or protein binding at that region. The long-term objective of my research is to understand how the BVDV 5' and 3' UTRs regulate virus replication so that we can identify ways to develop attenuated viral vaccines or control the cellular tropism of the virus and prevent infection of the fetus. In this proposal, our short-term objectives are to analyze the role of the BVDV 3 UTR in regulating the virus' life cycle. The 3' UTR is a structured RNA element and recent research showed that host cellular microRNAs, miR-17 and let-7, anneal to the 3' UTR and promote BVDV replication. We have preliminary data showing that small RNAs other than miR-17 or let-7 that also anneal to the 3' UTR can also promote BVDV replication. This suggests that any small RNA that binds is sufficient to promote virus replication, as long as it binds to the right region of the genome. Our goal is to identify the boundary of the domain to which miRNA annealing can promote BVDV replication. We will also determine the role of this domain in the virus' life cycle by analyzing growth of viruses having point mutations to this region. Finally we will identify the role of this domain in BVDV replication by analyzing the proteins that bind to it, how annealing of the miRNAs changes protein binding, and how this regulates BVDV replication. These studies will lead to a better understanding of the BVDV life cycle and the roles of the 3' UTR and its binding proteins and RNAs. This work may also identify ways to make new attenuated vaccines and strategies to limit vaccine replication to specific cell times and thus avoid vaccine spread to the fetus and prevent birth of PI calves from vaccinated pregnant cows.

牛病毒性腹泻病毒(BVDV)是养牛业的重要病原，可引起急性和持续性感染。急性感染降低了公牛和母牛的繁殖力，而小牛是感染源。PI牛犊是由BVDV在宫内感染急性感染的怀孕雌性动物造成的。BVDV的控制包括识别和扑杀猪犊，以及接种疫苗。然而，如果疫苗意外地接种给怀孕的雌性，用改良的活疫苗接种可能会导致PI小牛的出生。BVDV有一个+链的RNA基因组，它的复制受RNA基因组和与其结合的蛋白质的结构调节。特别是，5‘端和3’端区，即非翻译区(UTRs)，包含调节病毒翻译和复制的序列和结构。此外，少数病毒，丙型肝炎病毒(HCV)和BVDV的UTRs也与促进病毒生命周期的miRNAs结合，可能是通过调节它们所结合的RNA的功能，改变该区域的RNA结构和/或蛋白质结合。我研究的长期目标是了解BVDV 5‘和3’UTRs是如何调控病毒复制的，以便我们能够找到开发减毒病毒疫苗或控制病毒的细胞趋向性和预防胎儿感染的方法。在这项提案中，我们的短期目标是分析BVDV 3非编码区在调节病毒生命周期中的作用。3‘非编码区是一种结构化的RNA元件，最近的研究表明宿主细胞中的microRNAs miR-17和let-7与3’非编码区结合并促进BVDV的复制。我们有初步的数据表明，除miR-17或let-7外的小RNA也可以促进BVDV的复制。这表明，任何结合的小RNA都足以促进病毒复制，只要它结合到基因组的正确区域。我们的目标是确定miRNA退火可以促进BVDV复制的结构域的边界。我们还将通过分析具有该区域点突变的病毒的生长来确定该结构域在病毒生命周期中的作用。最后，我们将通过分析与BVDV结合的蛋白质，miRNAs的退火如何改变蛋白质结合，以及这如何调节BVDV复制，来确定该结构域在BVDV复制中的作用。这些研究将有助于更好地了解BVDV的生活史和3‘UTR及其结合蛋白和RNA的作用。这项工作还可能确定制造新的减毒疫苗的方法和策略，将疫苗复制限制在特定的细胞时间，从而避免疫苗传播到胎儿，防止接种疫苗的怀孕奶牛产下PI小牛。