《生命科学》 2014, 26(4): 384-391

RdDM途径中的重要蛋白质

徐　驰^1#，田　静^2#，莫蓓莘^1*

(1 深圳大学生命科学学院，深圳市微生物基因工程重点实验室，深圳 518060；2 深圳大学生命科学学院，深圳市海洋生物技术与生态环境重点实验室，深圳 518060)

摘　要：异染色质siRNAs 通过RNA 指导的DNA 甲基化(RdDM) 途径在胞嘧啶甲基化过程中扮演重要角色。RdDM 是沉默转座子和重复序列的重要表观遗传修饰。RdDM 主要包括4 个过程：24-nt siRNAs 的产生、支架RNA(scaffold RNA) 的合成、沉默复合体到沉默位点的募集和DNA 甲基化。在拟南芥中已经发现了一系列参与这4 个过程的蛋白质。通过介绍RdDM 途径中的重要蛋白质，说明RdDM 途径及其在植物体内的主要功能，重点论述了最新报道的作用机制和新RdDM 组分在该途径中的作用。

The important proteins of RNA-directed DNA methylation pathways

XU Chi^1#， TIAN Jing^2#， MO Bei-Xin^1*

(1 College of Life Science， Shenzhen Key Laboratory of Microbial Genetic Engineering， Shenzhen University， Shenzhen 518060， China; 2 College of Life Science， Shenzhen Key Laboratory of Marine Biological Resources and Ecological
    Environment， Shenzhen University， Shenzhen 518060， China)

Abstract: Heterochromatic siRNAs play a major role in directing cytosine methylation through the process of RNAdirected DNA methylation (RdDM). RdDM is an important epigenetic mechanism for silencing transposons and other repetitive elements， which includes mainly four phases: 24-nt siRNA production， scoffold RNA production， recruitment of the silencing complex to genomic targets， and DNA methylation. Various proteins involved in these fours phases have been identified in Arabidopsis thaliana. This paper described the RdDM pathway and its functions in plants based on the important proteins of the RdDM pathway， and then mainly discussed the latest reports on the mechanisms of the RdDM pathway and the role of some new RdDM components.