A structural-maintenance-of-chromosomes hinge domain-containing protein is required for RNA-directed DNA methylation
A structural-maintenance-of-chromosomes hinge domain-containing protein is required for RNA-directed DNA methylation
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DOI：
10.1038/ng.119
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发表时间：
2008-05-01
期刊：
影响因子：
30.8
通讯作者：
Matzke, Antonius J. M.
中科院分区：
文献类型：
--
作者：
Kanno, Tatsuo;Bucher, Etienne;Matzke, Antonius J. M.
RNA指导的DNA甲基化（RdDM）是其中dicer产生的小RNA指导同源DNA区域的从头胞嘧啶甲基化的过程（1，2）。为了鉴定对拟南芥发育重要的RdDM机制的组成部分，我们靶向了在分生组织中活跃的甲基化增强子，这导致下游GFP报告基因的沉默。这种沉默系统还具有次级siRNA的特征，其触发甲基化扩散到靶向增强子区域之外。对分生组织沉默和增强子甲基化缺陷突变体的筛选检索到六个dms互补组，其包括已知因子DRD 1（参考文献3; SNF 2样染色质重塑蛋白）和Pol IVb亚基（4，5）。此外，我们确定了一个以前未知的基因DMS 3（At 3g 49250），编码的蛋白质类似的铰链结构域区域的结构维持的染色体（SMC）蛋白。这一发现暗示了一种假定的染色体结构蛋白，其可以潜在地连接核酸（6），以促进涉及二级siRNA和DNA甲基化扩散的RNAi介导的表观遗传修饰。
RNA-directed DNA methylation (RdDM) is a process in which dicer-generated small RNAs guide de novo cytosine methylation at the homologous DNA region(1,2). To identify components of the RdDM machinery important for Arabidopsis thaliana development, we targeted an enhancer active in meristems for methylation, which resulted in silencing of a downstream GFP reporter gene. This silencing system also features secondary siRNAs, which trigger methylation that spreads beyond the targeted enhancer region. A screen for mutants defective in meristem silencing and enhancer methylation retrieved six dms complementation groups, which included the known factors DRD1 (ref. 3; a SNF2-like chromatin-remodeling protein) and Pol IVb subunits(4,5). Additionally, we identified a previously unknown gene DMS3 (At3g49250), encoding a protein similar to the hinge-domain region of structural maintenance of chromosomes (SMC) proteins. This finding implicates a putative chromosome architectural protein that can potentially link nucleic acids(6) in facilitating an RNAi-mediated epigenetic modification involving secondary siRNAs and spreading of DNA methylation.