Biology of Circoviruses

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。

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.