Xie Zhixin, Qi Xiaopeng
Department of Biological Sciences, Texas Tech University, P. O. Box 43131, Lubbock, Texas 79409, USA.
Biochim Biophys Acta. 2008 Nov;1779(11):720-4. doi: 10.1016/j.bbagrm.2008.02.009. Epub 2008 Mar 4.
Small silencing RNAs of 21- to 24-nucleotide (nt) in length are essential regulatory components expressed in most eukaryotic organisms. These regulatory small RNAs are produced through pathways that involve several evolutionarily conserved protein families, including DICER (DCR) or DICER-LIKE (DCL), ARGONAUTE (AGO), and RNA-DEPENDENT RNA POLYMERASE (RDR). Plants possess multiple functional DCL, RDR, and AGO proteins. Genetic analyses in the model plant Arabidopsis thaliana have revealed multiple small RNA pathways, each utilizing a distinct set of RNA silencing factors. In this short review, mainly based on the work done on A. thaliana, we give a brief overview on the multiple small RNA-directed silencing pathways in plants, which includes the biogenesis and function of microRNAs (miRNAs), trans-acting siRNAs (ta-siRNAs), natural cis-antisense transcripts-associated siRNAs (nat-siRNAs), and heterochromatic siRNAs.
长度为21至24个核苷酸（nt）的小干扰RNA是大多数真核生物中表达的重要调控成分。这些调控性小RNA通过涉及几个进化上保守的蛋白质家族的途径产生，包括Dicer（DCR）或Dicer-like（DCL）、AGO蛋白（AGO）和RNA依赖的RNA聚合酶（RDR）。植物拥有多种功能性DCL、RDR和AGO蛋白。模式植物拟南芥中的遗传分析揭示了多种小RNA途径，每种途径都利用一组不同的RNA沉默因子。在这篇简短的综述中，主要基于对拟南芥所做的工作，我们简要概述了植物中多种小RNA介导的沉默途径，其中包括微小RNA（miRNA）、反式作用小干扰RNA（ta-siRNA）、天然顺式反义转录本相关小干扰RNA（nat-siRNA）和异染色质小干扰RNA的生物合成和功能。
