摘 要：摘 要：RNA沉默(RNA silencing)是真核生物中的一种抵抗外源遗传因子(病毒、转座子或转基因)及调控基因表达的防御机制。参与植物RNA沉默的酶及蛋白质主要包括6种RNA依赖的RNA聚合酶、4种Dicer-like (DCL)核酸内切酶和10种Argonautes蛋白。植物中4条RNA沉默途径分别由微小RNA (miRNAs)和3种小干扰RNA (siRNAs)介导，包括反式作用siRNAs (ta-siRNAs)、天然反义siRNAs (nat-siRNAs)和异染色质siRNAs (hc-siRNAs)。 在植物RNA沉默的系统性传播中，由DCL4或DCL2将dsRNAs裁剪为次级siRNAs，以放大RNA沉默信号和增强沉默效应。
关键词：RNA沉默；RNA依赖的RNA聚合酶；Dicer-like核酸内切酶；Argonaute蛋白；微小RNA；小干扰RNA;沉默途径; 系统性RNA沉默
中图分类号：Q946; Q752; Q943.2 文献标识码：A
Abstract: Abstract: RNA silencing is a defense mechanism in eukaryotes which can resist the exogenous genetic factors (virus, transposon or transgene) and regulate gene expression. It was found that many important enzymes and proteins are involved in the RNA silencing of plants, including 6 kinds of RNA-dependent RNA polymerases, 4 types of Dicer-like (DCL) endoribonucleases and 10 kinds of argonautes protein. In plants, four RNA silencing pathways are directed by microRNAs (miRNAs) and three types of small interfering RNAs (siRNAs) which are trans-acting siRNAs (ta-siRNAs), natural antisense siRNAs (nat-siRNAs) and heterochromatin siRNAs (hc-siRNAs). In the systematic RNA silencing, DCL4 or/and DCL2 process dsRNAs into the secondary siRNAs to amplify silencing signals and effects.
Key words: RNA silencing; RNA-dependent RNA polymerase; dicer-like endoribonuclease; argonaute protein; microRNAs; small interfering RNAs; silencing pathways; systematic RNA silencing
