microRNA-directed phasing during trans-acting siRNA biogenesis in plants
microRNA-directed phasing during trans-acting siRNA biogenesis in plants
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DOI：
10.1016/j.cell.2005.04.004
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发表时间：
2005-04-22
期刊：
影响因子：
64.5
通讯作者：
Carrington, JC
中科院分区：
文献类型：
--
作者：
Allen, E;Xie, ZX;Carrington, JC
植物和动物使用小RNA（microRNA [miRNAs]和siRNA）作为转录后和表观遗传调控的指导。在植物中，miRNA和反式作用（ta）siRNA通过不同的生物合成途径形成，尽管它们都与靶转录物相互作用并引导切割。一种识别拟南芥miRNA和ta-siRNA靶点的综合方法揭示了几类新的小RNA调控基因，包括传统基因如Argonaute 2和E2-泛素缀合酶。令人惊讶的是，五种tasiRNA生成转录物被鉴定为miR 173或miR 390的靶标。miR 173和miR 390引导的切割显示为ta-siRNA前体加工设定21个核苷酸的阶段，而不是作为负调节剂发挥作用。这些数据支持一种模型，其中在pre-ta-siRNA转录物内miRNA引导的5'或3'末端的形成，随后是dsRNA的RDR 6依赖性形成和Dicer样加工，产生负调节其他基因的定相ta-siRNA。
Plants and animals use small RNAs (microRNAs [miRNAs] and siRNAs) as guides for posttranscriptional and epigenetic regulation. In plants, miRNAs and trans-acting (ta) siRNAs form through distinct biogenesis pathways, although they both interact with target transcripts and guide cleavage. An integrated approach to identify targets of Arabidopsis thaliana miRNAs and ta-siRNAs revealed several new classes of small RNA-regulated genes, including conventional genes such as Argonaute2 and an E2-ubiquitin conjugating enzyme. Surprisingly, five tasiRNA-generating transcripts were identified as targets of miR173 or miR390. Rather than functioning as negative regulators, miR173- and miR390-guided cleavage was shown to set the 21-nucleotide phase for ta-siRNA precursor processing. These data support a model in which miRNA-guided formation of a 5' or 3' terminus within pre-ta-siRNA transcripts, followed by RDR6-dependent formation of dsRNA and Dicer-like processing, yields phased ta-siRNAs that negatively regulate other genes.