A plant RNA virus suppresses RNA silencing through viral RNA replication
A plant RNA virus suppresses RNA silencing through viral RNA replication
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DOI：
10.1038/sj.emboj.7600776
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发表时间：
2005-09-07
期刊：
影响因子：
11.4
通讯作者：
Okuno, T
中科院分区：
文献类型：
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作者：
Takeda, A;Tsukuda, M;Okuno, T
RNA干扰（RNAi）是在许多真核生物中起作用的转录后基因调控机制。RNAi由双链RNA （dsRNA）诱导，主要参与对转座子和病毒的防御。为了对抗RNAi，病毒有RNAi抑制因子。在这里，我们展示了植物病毒红三叶草坏死花叶病毒（RCNMV）抑制RNAi的新机制。为了抑制RNAi， RCNMV需要多种病毒成分，其中包括病毒RNA和假定的RNA复制酶蛋白。负链RNA合成所需的RNA元件与RNAi抑制之间的密切关系表明病毒RNA复制机制与RNAi机制之间存在密切联系。在一项瞬时实验中，RCNMV干扰了发夹dsRNA诱导的RNAi中小干扰RNA （sirna）的积累，也干扰了microRNA （miRNA）的生物发生。拟南芥dcl1突变体对RCNMV感染的易感性降低。基于这些结果，我们提出了一个模型，在这个模型中，为了复制，RCNMV剥夺了参与siRNA和miRNA生物发生的dicer样酶的RNAi机制。
RNA interference (RNAi) is a post-transcriptional gene-regulatory mechanism that operates in many eukaryotes. RNAi is induced by double-stranded RNA ( dsRNA) and is mainly involved in defence against transposons and viruses. To counteract RNAi, viruses have RNAi suppressors. Here we show a novel mechanism of RNAi suppression by a plant virus Red clover necrotic mosaic virus ( RCNMV). To suppress RNAi, RCNMV needs multiple viral components, which include viral RNAs and putative RNA replicase proteins. A close relationship between the RNA elements required for negative-strand RNA synthesis and RNAi suppression suggests a strong link between the viral RNA replication machinery and the RNAi machinery. In a transient assay, RCNMV interferes with the accumulation of small-interfering RNA (siRNAs) in RNAi induced by a hairpin dsRNA and it also interferes with microRNA ( miRNA) biogenesis. An Arabidopsis dcl1 mutant showed reduced susceptibility to RCNMV infection. Based on these results, we propose a model in which, to replicate, RCNMV deprives the RNAi machinery of Dicer-like enzymes that are involved in both siRNA and miRNA biogenesis.