MicroRNA-directed siRNA biogenesis in Caenorhabditis elegans.
MicroRNA-directed siRNA biogenesis in Caenorhabditis elegans.
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DOI：
10.1371/journal.pgen.1000903
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发表时间：
2010-04-08
期刊：
影响因子：
4.5
通讯作者：
Ketting RF
中科院分区：
文献类型：
--
作者：
Corrêa RL;Steiner FA;Berezikov E;Ketting RF
RNA干扰（RNAi）是由双链RNA（dsRNA）触发的转录后沉默过程，导致同源mRNA的不稳定。已经在内源性RNAi相关途径和外源性RNAi途径之间进行了区分，后者对于RNAi的实验使用是必需的。先前的研究表明，在秀丽隐杆线虫中，含有Dicer酶和Argonaute RDE-1的复合物处理dsRNA。Dicer负责将dsRNA切割成短干扰RNA（siRNA），而RDE-1充当siRNA受体。RDE-1然后引导多蛋白复合物到同源靶标以触发mRNA去稳定化。然而，RDE-1的内源性作用（如果有的话）尚未探索。我们在这里表明RDE-1作为一种清道夫蛋白发挥作用，从许多不同来源摄取小RNA分子，包括microRNA（miRNA）途径。这与直接在miRNA途径中起作用的Argonaute蛋白质ALG-1和ALG-2形成鲜明对比：这些蛋白质专门结合miRNA。RDE-1虽然在主要miRNA库的生物发生中没有发挥重要作用，但它结合内源性miRNA并在至少一个完全匹配的内源性miRNA靶标上触发RdRP活性。所产生的二级siRNA被一组Argonaute蛋白吸收，已知其在外源RNAi中充当siRNA受体，导致强烈的mRNA去稳定化。我们的研究结果表明，RDE-1在内源性环境中使用许多不同的小RNA（包括miRNA）作为指导，积极筛选转录组，这对转录本的进化具有影响，可能被Dicer识别。由于其固有的特性，RNA干扰（RNAi）已成为细胞生物学中最广泛使用的工具之一，并彻底改变了阐明基因功能的方法。这个过程也被称为RNA沉默，是由dsRNA分子触发的，dsRNA分子被Dicer蛋白切割成小干扰RNA（siRNA）。来自秀丽隐杆线虫的rde-1基因是最早发现的与该机制相关的基因之一，并且编码蠕虫中唯一的Argonaute蛋白，其本身对于由外源引入的dsRNA触发的经典RNAi途径是必需的。然而，很少有人知道RDE-1的内源性功能。在这里，我们发现RDE-1与许多类型的小RNA结合，包括microRNA。我们发现，miR-243被RDE-1有效地结合，并在内源性靶点上触发常规RNAi，这意味着许多RNA种类，包括miRNA，正在使用经典的外源性RNAi途径针对转录组进行筛选。
RNA interference (RNAi) is a post-transcriptional silencing process, triggered by double-stranded RNA (dsRNA), leading to the destabilization of homologous mRNAs. A distinction has been made between endogenous RNAi–related pathways and the exogenous RNAi pathway, the latter being essential for the experimental use of RNAi. Previous studies have shown that, in Caenorhabditis elegans, a complex containing the enzymes Dicer and the Argonaute RDE-1 process dsRNA. Dicer is responsible for cleaving dsRNA into short interfering RNAs (siRNAs) while RDE-1 acts as the siRNA acceptor. RDE-1 then guides a multi-protein complex to homologous targets to trigger mRNA destabilization. However, endogenous role(s) for RDE-1, if any, have remained unexplored. We here show that RDE-1 functions as a scavenger protein, taking up small RNA molecules from many different sources, including the microRNA (miRNA) pathway. This is in striking contrast to Argonaute proteins functioning directly in the miRNA pathway, ALG-1 and ALG-2: these proteins exclusively bind miRNAs. While playing no significant role in the biogenesis of the main pool of miRNAs, RDE-1 binds endogenous miRNAs and triggers RdRP activity on at least one perfectly matching, endogenous miRNA target. The resulting secondary siRNAs are taken up by a set of Argonaute proteins known to act as siRNA acceptors in exogenous RNAi, resulting in strong mRNA destabilization. Our results show that RDE-1 in an endogenous setting is actively screening the transcriptome using many different small RNAs, including miRNAs, as a guide, with implications for the evolution of transcripts with a potential to be recognized by Dicer. Due to its intrinsic characteristics, RNA interference (RNAi) has become one of the most widely used tools in cell biology and has revolutionized approaches to elucidate gene function. The process, also known as RNA silencing, is triggered by dsRNA molecules that are cleaved by Dicer proteins into small interfering RNAs (siRNAs). The rde-1 gene from Caenorhabditis elegans was one of the first genes found in association with this mechanism and encodes the only Argonaute protein in worms, which is by itself essential for the classical RNAi pathway triggered by exogenously introduced dsRNA. However, little is known about endogenous functions of RDE-1. Here we show that RDE-1 binds to many classes of small RNAs, including microRNAs. We show that miR-243 is efficiently bound by RDE-1 and triggers regular RNAi on an endogenous target, implying that many RNA species, including miRNAs, are constantly being screened against the transcriptome using the canonical exogenous RNAi pathway.
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影响因子：
3.7
作者：
Fahlgren N;Howell MD;Kasschau KD;Chapman EJ;Sullivan CM;Cumbie JS;Givan SA;Law TF;Grant SR;Dangl JL;Carrington JC
通讯作者：
Carrington JC
DOI：
10.1073/pnas.0906378106
发表时间：
2009-11-03
影响因子：
11.1
作者：
Han, Ting;Manoharan, Arun Prasad;Kim, John K.
通讯作者：
Kim, John K.
影响因子：
56.9
作者：
LABEIT, S;KOLMERER, B
通讯作者：
KOLMERER, B
影响因子：
64.5
作者：
Grishok, A;Pasquinelli, AE;Mello, CC
通讯作者：
Mello, CC
影响因子：
11.4
作者：
Aoki, Kazuma;Moriguchi, Hiromi;Tabara, Hiroaki
通讯作者：
Tabara, Hiroaki