Nature：与基因沉默有关的特殊基因RDM1- 生物研究- 生物谷

最新一期英国《自然》杂志网络版发表了这个国际科研小组的论文。这一科研小组发现的特殊基因名为RDM1，它可以编码生成一种小蛋白，从而参与指导其他基因的表达。

科学家指出，基因一般处于被保护状态中，只有通过所谓的甲基化，即与甲基接触，才能表达并发挥作用。如果去除RDM1，被保护的基因就无法甲基化，也就无法进行表达。

由于每一个植物细胞中都存在着完整的遗传信息，因此必须让某些基因保持“沉默”，植物具体的器官才能顺利地发挥各自作用。否则，所有基因就会都来表达，植物器官也将不知道听从谁的“指令”。一般在一个植物的上万个基因里，只有很少的一部分能够表达，RNA（核糖核酸）会对需要表达的基因进行标记。RDM1基因的任务就是让RNA标记过的基因表达。缺少了RDM1，植物中许多本该表达的基因就会保持“沉默”，植物无法正常生长。(生物谷Bioon.com)

延伸阅读

Nature ：有丝分裂过程中引起基因沉默的原因
The Plant Journal ：人工miRNA介导基因沉默
Science ：RNAi调控基因沉默的研究
Nature Cell Biology： 美开发出新型基因沉默技术

生物谷推荐原文出处：

Nature doi:10.1038/nature09025

An RNA polymerase II- and AGO4-associated protein acts in RNA-directed DNA methylation
ZhihuanGao1,10, Hai-Liang Liu1,2,10, Lucia Daxinger3,10,11, Olga Pontes4,10,Xinjian He1,5, Weiqiang Qian1, Huixin Lin1, Mingtang Xie1, Zdravko J.Lorkovic6, Shoudong Zhang1,5, Daisuke Miki1, Xiangqiang Zhan1,5,Dominique Pontier7, Thierry Lagrange7, Hailing Jin8, Antonius J. M.Matzke3, Marjori Matzke3, Craig S. Pikaard9 & Jian-Kang Zhu1,5

Institute for Integrative Genome Biology and Department of Botany andPlant Sciences, University of California, Riverside, California 92521,USA
School of life science and technology, Tongji University, Shanghai 200092, China
Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, 1030 Vienna, Austria
Biology Department, Washington University, St Louis, Missouri 63130, USA
Centerfor Plant Stress Genomics and Technology, 4700 King Abdullah Universityof Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia
Max F. Perutz Laboratory, Medical University of Vienna, 1030 Vienna, Austria
LGDP, CNRS/IRD/Université de Perpignan, UMR 5096, 66860 Perpignan, France
Institutefor Integrative Genome Biology and Department of Plant Pathology andMicrobiology, University of California, Riverside, California 92521, USA
Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
These authors contributed equally to this work.

DNA methylation is an important epigenetic mark in many eukaryotes1,2, 3, 4, 5. In plants, 24-nucleotide small interfering RNAs (siRNAs)bound to the effector protein, Argonaute 4 (AGO4), can direct de novoDNA methylation by the methyltransferase DRM2 (refs 2, 4–6). Here wereport a new regulator of RNA-directed DNA methylation (RdDM) inArabidopsis: RDM1. Loss-of-function mutations in the RDM1 gene impairthe accumulation of 24-nucleotide siRNAs, reduce DNA methylation, andrelease transcriptional gene silencing at RdDM target loci. RDM1 encodesa small protein that seems to bind single-stranded methyl DNA, andassociates and co-localizes with RNA polymerase II (Pol II, also knownas NRPB), AGO4 and DRM2 in the nucleus. Our results indicate that RDM1is a component of the RdDM effector complex and may have a role inlinking siRNA production with pre-existing or de novo cytosinemethylation. Our results also indicate that, although RDM1 and Pol V(also known as NRPE) may function together at some RdDM target sites inthe peri-nucleolar siRNA processing centre, Pol II rather than Pol V isassociated with the RdDM effector complex at target sites in thenucleoplasm.