Biology of Circoviruses

圆环病毒生物学

• 批准号: RGPIN-2016-06291
• 负责人: Teodoro, Jose
• 金额: $ 2.4万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616214
• 关键词: Biology; Circoviruses

BACKGROUND. Circoviruses are small, non-enveloped icosahedral viruses that are important pathogens of several animal species. Infectious chicken anemia, is caused by a circovirus called chicken anemia virus (CAV). Controlling outbreaks of CAV during intensive poultry farming is costly and disruptive. Circovirus genomes are small, ranging between 1.7-2.3 kb and circular, which gives the family its name. CAV encodes only 3 open reading frames (ORFs). Pathogenicity of the virus in chickens is due to a single ORF, designated viral protein 3 (VP3), which causes extensive apoptosis in infected cells and is required for efficient viral replication. In order to understand how CAV-VP3 induces cell death, our group purified the cellular protein complexes associated with this protein and found that CAV-VP3 binds to the anaphase promoting complex/cyclosome (APC/C). Several diverse types of virus including Papillomavirus, Adenovirus, Herpesvirus, Poxvirus and Circovirus have all been shown to have proteins that bind and inactivate the APC/C. Although this wide range of viruses have convergently evolved strategies to inhibit the APC/C, the functional importance of this interaction during viral replication is unknown. Continued study of the biology of CAV can therefore provide fundamental insights into general mechanisms of molecular virology and cell biology. RESEARCH PROGRAM. Our previous studies focused on the mechanism of cytotoxicity of the VP3 protein of CAV. We found that CAV-VP3 interacts with critical components of the cell cycle and DNA damage response pathway. We now plan to continue our research program by examining how these properties of CAV-VP3 enhance viral replication and spread. SPECIFIC AIMS. Aim 1. Functions of the CAV-VP3 protein required for efficient viral replication. Our studies have shown that nuclocytoplasmic shuttling and multimerization activity of CAV-VP3 is required for the cytotoxic properties of the protein. We will utilize an in vitro replication system of CAV to assess the impact of each of these activities of CAV-VP3 on replication. Aim 2. The role the CAV-VP3 interaction with the APC/C in viral replication. CAV-VP3 interacts and inhibits the anaphase-promoting complex (APC), a critical component of the cell cycle regulatory machinery. In this aim we will study how inhibition of the APC promotes viral replication. Aim 3. The CAV-VP3 protein as a DNA damage sensor and modulator of DNA damage responses. We have observed that CAV-VP3 is able to attenuate cellular DNA damage responses. In the final aim we will study how CAV-VP3 is targeted by the DNA damage signaling pathway and the importance of these interactions for efficient viral replication.

背景 圆环病毒是一种小型无包膜二十面体病毒，是几种动物的重要病原体。鸡传染性贫血是由一种叫做鸡贫血病毒（CAV）的圆环病毒引起的。在集约化家禽养殖中控制CAV的爆发是昂贵的和破坏性的。圆环病毒的基因组很小，在1.7-2.3 kb之间，呈圆形，因此得名。CAV仅编码3个开放阅读框（ORF）。该病毒在鸡中的致病性是由于单个ORF，命名为病毒蛋白3（VP 3），其引起感染细胞中的广泛凋亡，并且是有效病毒复制所需的。为了了解CAV-VP 3是如何诱导细胞死亡的，我们的小组纯化了与该蛋白相关的细胞蛋白复合物，发现CAV-VP 3与后期促进复合物/环体（APC/C）结合。包括乳头瘤病毒、腺病毒、疱疹病毒、痘病毒和圆环病毒在内的几种不同类型的病毒都已显示具有结合和包裹APC/C的蛋白质。虽然这种广泛的病毒已经收敛地进化策略来抑制APC/C，但这种相互作用在病毒复制期间的功能重要性是未知的。因此，对CAV生物学的持续研究可以为分子病毒学和细胞生物学的一般机制提供基本的见解。 研究报告 本课题组前期的研究主要集中在CAV VP 3蛋白的细胞毒作用机制上。我们发现CAV-VP 3与细胞周期和DNA损伤反应途径的关键组分相互作用。我们现在计划通过研究CAV-VP 3的这些特性如何增强病毒复制和传播来继续我们的研究计划。 具体目标。 目标1。有效病毒复制所需的CAV-VP 3蛋白的功能。 我们的研究表明，CAV-VP 3的核质穿梭和多聚化活性是该蛋白的细胞毒性特性所必需的。我们将利用CAV的体外复制系统来评估CAV-VP 3的这些活性中的每一个对复制的影响。 目标二。CAV-VP 3与APC/C相互作用在病毒复制中的作用。 CAV-VP 3相互作用并抑制后期促进复合物（APC），这是细胞周期调节机制的关键组分。在这个目标中，我们将研究APC的抑制如何促进病毒复制。 目标3. CAV-VP 3蛋白作为DNA损伤传感器和DNA损伤反应的调节剂。 我们已经观察到CAV-VP 3能够减弱细胞DNA损伤反应。在最后的目标中，我们将研究CAV-VP 3如何被DNA损伤信号通路靶向，以及这些相互作用对有效病毒复制的重要性。