Suppression of endogenous gene silencing by bidirectional cytoplasmic RNA decay in Arabidopsis
Suppression of endogenous gene silencing by bidirectional cytoplasmic RNA decay in Arabidopsis
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DOI：
10.1126/science.aaa2618
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发表时间：
2015-04
期刊：
影响因子：
56.9
通讯作者：
Xinyan Zhang;Ying Zhu;Xiaodan Liu;Xinyu Hong;Yang Xu;P. Zhu;Yang Shen;Huihui Wu;Yusi Ji;X. Wen;Chen Zhang;Qiong Zhao;Yichuan Wang;Jian Lu;Hongwei Guo
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作者：
Xinyan Zhang;Ying Zhu;Xiaodan Liu;Xinyu Hong;Yang Xu;P. Zhu;Yang Shen;Huihui Wu;Yusi Ji;X. Wen;Chen Zhang;Qiong Zhao;Yichuan Wang;Jian Lu;Hongwei Guo
防止失控的防御系统RNA干扰保护细胞免受入侵的遗传因素，如病毒或转基因。但是，当侵入性RNA受到攻击时，是什么保护了正常的内源性RNA呢？Zhang等人在小型植物拟南芥中发现了一种监视系统，可以做到这一点：保护正常的转录组，并将攻击集中在入侵转录本上。《科学》，本期第120页。模式植物拟南芥使用额外的RNA干扰层来保护自己的转录组。转录后基因沉默（PTGS）是植物抵抗外源基因入侵的重要机制。植物如何精心避免不适当的PTGS内源编码基因仍然不清楚。我们在拟南芥中证明，5 '-3'和3 '-5'细胞质RNA衰变途径都充当转基因和内源PTGS的抑制子。双向胞质RNA衰变的破坏导致多效性发育缺陷和剧烈的转录组学改变，这基本上是由PTGS突变体拯救的。当双向RNA衰变功能障碍时，编码转录物产生大量21- 22个核苷酸的内源性小干扰RNA，包括多个microRNA靶标，其可干扰其同源基因表达和功能。这项研究强调了不需要的PTGS的风险，并确定了细胞质RNA衰变途径作为植物转录组和发育的保障。
Protecting against runaway defense systems RNA interference defends cells against invading genetic elements, such as viruses or transgenes. But while the invasive RNAs are under attack, what protects the normal endogenous RNAs? Zhang et al. identified, in the small plant Arabidopsis, a surveillance system to do just that: Preserve the normal transcriptome and keep the attack focused on invasive transcripts. Science, this issue p. 120 The model plant Arabidopsis uses extra layers of RNA interference to protect its own transcriptome. Plant immunity against foreign gene invasion takes advantage of posttranscriptional gene silencing (PTGS). How plants elaborately avert inappropriate PTGS of endogenous coding genes remains unclear. We demonstrate in Arabidopsis that both 5′-3′ and 3′-5′ cytoplasmic RNA decay pathways act as repressors of transgene and endogenous PTGS. Disruption of bidirectional cytoplasmic RNA decay leads to pleiotropic developmental defects and drastic transcriptomic alterations, which are substantially rescued by PTGS mutants. Upon dysfunction of bidirectional RNA decay, a large number of 21- to 22-nucleotide endogenous small interfering RNAs are produced from coding transcripts, including multiple microRNA targets, which could interfere with their cognate gene expression and functions. This study highlights the risk of unwanted PTGS and identifies cytoplasmic RNA decay pathways as safeguards of plant transcriptome and development.