Unravelling the nuclear manipulation by geminiviruses

双生病毒属是一类具有环状基因组的单链DNA植物病毒，是世界范围内农作物病害的主要病原。双生病毒复制发生在细胞核中，并使用植物DNA复制机制;双生病毒基因组形成微型染色体，并进行表观遗传修饰，这似乎在双生病毒-植物相互作用的结果中发挥重要作用;病毒的核化也发生在细胞核中。很明显，细胞核是双生病毒入侵的最重要的亚细胞区室;然而，缺乏关于病毒相关过程的亚核分布的空间信息。有趣的是，双生病毒感染和/或特异性病毒蛋白的表达诱导核结构的特征性变化，例如，在联合表达Abutilon花叶病毒转运蛋白MP和NSP时，内核囊泡衍生的囊泡内陷到核中，但也出现与核表面相关。此外，双生病毒感染细胞中核标记物定位的变化也反映了核组织的改变。这些观察结果表明，植物病毒复制和穿梭/运动蛋白的协同作用导致重组的核和膜结构域，这可能是必不可少的病毒复制，逃避植物抗病毒机制，和贩运。因此，本提案的目的是i）深入了解双生病毒的核重组和操纵; ii）定义双生病毒的核相互作用组;和iii）鉴定病毒操纵的核靶标。核输入、颠覆和输出对于病毒感染的建立至关重要;深入了解这些过程如何发生将为设计有效的抗病毒策略铺平道路。由于旨在削弱病毒对细胞核的协同选择的策略可能会影响病毒复制，因此它们将使潜在突变病毒版本的出现最小化，从而提供持久的抗性。

Geminiviruses constitute a large and economically important group of single-stranded (ss) DNA plant viruses with circular genomes, causal agents of devastating crop diseases worldwide. Geminiviral replication occurs in the nucleus and uses the plant DNA replication machinery; the geminiviral genome forms minichromosomes and is subjected to epigenetic modifications, which seem to play an important role in the outcome of geminivirus-plant interactions; viral encapsidation also takes place in the nucleus. It is obvious that the nucleus is the most important subcellular compartment for geminiviral invasion; spatial information regarding the subnuclear distribution of virus-related processes, however, is lacking. Interestingly, geminiviral infection and/or expression of specific viral proteins induce characteristic changes in nuclear architecture, e.g. upon combined expression of Abutilon mosaic virus transport proteins, MP and NSP, inner nuclear envelope-derived vesicles invaginate into nuclei, but also appear associated with the nuclear surface. Additionally, changes in the localization of nuclear markers in geminivirus-infected cells also reflect an alteration of nuclear organization. These observations suggest that a concerted action of plant viral replication and shuttling/movement proteins leads to the re-organization of nuclear and membrane domains, which might be essential for viral replication, evasion of plant anti-viral mechanisms, and trafficking. Thus, the objectives of this proposal are i) to gain insight into the nuclear reorganization and manipulation by geminiviruses; ii) to define the nuclear interactome of geminiviruses; and iii) to identify nuclear targets of viral manipulation. Nuclear import, subversion, and export are essential for the establishment of the viral infection; a deep understanding of how these processes occur would pave the way for the design of efficient anti-viral strategies. Because strategies aimed at impairing the viral co-option of the nucleus would potentially impact viral replication, they would minimize the appearance of potential mutated viral versions, hence providing durable resistance.