Identification of an RNA silencing suppressor from a plant double-stranded RNA virus
Identification of an RNA silencing suppressor from a plant double-stranded RNA virus
复制标题
植物双链 RNA 病毒 RNA 沉默抑制子的鉴定
DOI：
10.1128/jvi.79.20.13018-13027.2005
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发表时间：
2005-10-01
影响因子：
5.4
通讯作者：
Li, Y
中科院分区：
文献类型：
--
作者：
Cao, XS;Zhou, P;Li, Y
RNA沉默是高等植物和动物进化出的一种防御病毒感染的机制，也是一种调节基因表达以促进生长发育的机制。作为一种防御手段，迄今为止研究的许多植物和一些动物病毒编码RNA沉默抑制子（RSS），干扰沉默途径的各个步骤。在这项研究中，我们首次从植物双链RNA （dsRNA）病毒中鉴定出RSS。Pns10由水稻矮化植物呼肠病毒（RDV） S10编码，在携带绿色荧光蛋白的转基因本烟16c中与报告绿色荧光蛋白（GFP）共浸润试验中表现出RSS活性。RDV基因组的其他基因片段没有这样的功能。Pns10可抑制sense RNA诱导的局部和全身沉默，但不干扰dsRNA诱导的局部和全身沉默。在瞬时检测中，Pns10的表达也增加了β-葡萄糖醛酸酶的表达，并增强了马铃薯病毒X在拟南芥中的致病性。总之，我们的研究结果证实Pns10是由植物dsRNA病毒编码的RSS，并进一步表明Pns10靶向RNA沉默途径中dsRNA形成的上游步骤。
ABSTRACT RNA silencing is a mechanism which higher plants and animals have evolved to defend against viral infection in addition to regulation of gene expression for growth and development. As a counterdefense, many plant and some animal viruses studied to date encode RNA silencing suppressors (RSS) that interfere with various steps of the silencing pathway. In this study, we report the first identification of an RSS from a plant double-stranded RNA (dsRNA) virus. Pns10, encoded by S10 of Rice dwarf phytoreovirus (RDV), exhibited RSS activity in coinfiltration assays with the reporter green fluorescent protein (GFP) in transgenic Nicotiana benthamiana line 16c carrying GFP. The other gene segments of the RDV genome did not have such a function. Pns10 suppressed local and systemic silencing induced by sense RNA but did not interfere with local and systemic silencing induced by dsRNA. Expression of Pns10 also increased the expression of β-glucuronidase in transient assays and enhanced Potato virus X pathogenicity in N. benthamiana. Collectively, our results establish Pns10 as an RSS encoded by a plant dsRNA virus and further suggest that Pns10 targets an upstream step of dsRNA formation in the RNA silencing pathway.