RNA-silencing suppressors of geminiviruses
RNA-silencing suppressors of geminiviruses
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DOI：
10.1007/s10327-008-0085-5
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发表时间：
2008-04
影响因子：
1.2
通讯作者：
Pradeep Sharma;M. Ikegami
中科院分区：
文献类型：
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作者：
Pradeep Sharma;M. Ikegami
双生病毒是一类单链DNA病毒，不仅能在世界范围内引起重要粮食和纤维作物的毁灭性病害，而且是研究病毒诱导的基因沉默和RNA干扰的重要模型。作为一种反防御机制，病毒已经进化出各种反沉默策略，这些策略正在逐步被解开。双生病毒是在细胞核内复制的ssDNA分子，因此在复制过程中没有dsRNA相，它们既可以诱导基因沉默，也可以成为基因沉默的靶标。双链双生病毒的蛋白AC 2（编码转录激活蛋白）和AC 4以及单链病毒的蛋白C2（AC 2的位置同源物）已被鉴定为转录后基因沉默的抑制因子。迄今为止，大多数双生病毒抑制子的特点不共享任何明显的结构或序列相似性，除了他们已被确定为致病性决定因素的家庭和群体。本文主要综述了双生病毒编码的RNA沉默抑制蛋白--βC1和V2蛋白，以及它们在RNA沉默途径不同阶段的干扰作用。
Geminiviruses are single-stranded (ss) DNA viruses that not only cause devastating diseases of important food and fiber crops worldwide, but also are important models to study fundamental aspects of virus-induced gene silencing and RNA interference. As a counterdefense mechanism, viruses have evolved various antisilencing strategies that are being progressively unraveled. The geminiviruses, ssDNA molecules that replicate inside the nucleus and therefore have no dsRNA phase during replication, can both induce and become targets of gene silencing. Proteins AC2 (encoding the transcriptional activator protein) and AC4 of bipartite geminiviruses and protein C2, a positional homolog of AC2 of monopartite viruses, have been identified as suppressors of posttranscriptional gene silencing. The majorities of geminiviral suppressors characterized to date do not share any obvious structural or sequence similarity across families and groups except that they have been identified as pathogenicity determinants. This review mainly focuses on the geminivirus-encoded suppressors of RNA-silencing—the βC1 and V2 proteins—and their possible role in the interference of silencing at different steps in the pathways.