siRNA-mediated chromatin maintenance and its function in Arabidopsis thaliana
siRNA-mediated chromatin maintenance and its function in Arabidopsis thaliana
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DOI：
10.1016/j.bbagrm.2011.05.002
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发表时间：
2011-08-01
影响因子：
4.7
通讯作者：
Habu, Yoshiki
中科院分区：
文献类型：
--
作者：
Kanno, Tatsuo;Habu, Yoshiki
小干扰RNA（siRNA）广泛存在于各种真核生物中，并且参与染色质修饰的维持，特别是那些由胞嘧啶和/或组蛋白的共价修饰代表的惰性状态。与哺乳动物基因组中胞嘧啶甲基化主要限于CG二核苷酸序列相反，植物中的惰性染色质在所有序列背景下都携带胞嘧啶甲基化，并且siRNA通过RNA指导的DNA甲基化过程在指导胞嘧啶甲基化中发挥主要作用。该领域的最新进展揭示了siRNA介导的惰性染色质的维持在发育以及植物对环境的响应中具有不同的作用。已经在拟南芥中鉴定了siRNA介导的染色质修饰所需的各种蛋白质因子，并且已经投入了大量努力来理解它们的功能和相互作用，导致这些因子中的许多因子被分配到特定的生物化学活性和参与特定的步骤，例如基因间RNA的转录、RNA加工和胞嘧啶甲基化。然而，许多因子的精确功能仍然未指定，并且siRNA介导的染色质修饰的不同途径的相互作用在很大程度上是未知的。本文综述了siRNA介导的染色质修饰在A. thaliana，并提出了一些推测沉默因子的功能和相互作用，虽然尚未分配到定义的生化活动，已被松散地分配到siRNA介导的染色质修饰途径的特定事件。特刊题目：植物细胞和发育过程的表观遗传控制。(C)2011 Elsevier B. V.保留所有权利。
Small interfering RNAs (siRNAs) are widespread in various eukaryotes and are involved in maintenance of chromatin modifications, especially those for inert states represented by covalent modifications of cytosine and/or histones. In contrast to mammalian genomes, in which cytosine methylation is restricted mostly to CG dinucleotide sequences, inert chromatin in plants carries cytosine methylation in all sequence contexts, and siRNAs play a major role in directing cytosine methylation through the process of RNA-directed DNA methylation. Recent advances in this field have revealed that siRNA-mediated maintenance of inert chromatin has diverse roles in development as well as in plant responses to the environment. Various proteinaceous factors required for siRNA-mediated chromatin modification have been identified in Arabidopsis thaliana, and much effort has been invested in understanding their function and interaction, resulting in the assignment of many of these factors to specific biochemical activities and engagement with specific steps such as transcription of intergenic RNAs, RNA processing, and cytosine methylation. However, the precise functions of a number of factors remain undesignated, and interactions of distinct pathways for siRNA-mediated chromatin modification are largely unknown. In this review, we summarize the roles of siRNA-mediated chromatin modification in various biological processes of A. thaliana, and present some speculation on the functions and interactions of silencing factors that, while not yet assigned to defined biochemical activities, have been loosely assigned to specific events in siRNA-mediated chromatin modification pathways. Special Issue entitled: Epigenetic control of cellular and developmental processes in plants. (C) 2011 Elsevier B.V. All rights reserved.