两者均为植物特有的RdDM（RNA directed DNA methylation）通路中的核心组分，其中Pol IV在通路的上游协同RDR2一起生成前体siRNA，而Pol V则在下游产生lncRNA（long non-coding RNA）来招募DNA甲基转移酶从而引起基因组特定位点的基因沉默。因此与常规的DdRP转录并释放产物RNA不同，Pol V在功能上要求其滞留在染色质上...
【答案】：首先在植物中发现的一种RNA指导的沉默机制。类似于：RNA干扰(RNAi)，RdI)M也需要21～26nt的双链RNA片段。与短双链RNA同源的DNA序列被甲基化，从而使基因沉默。
两者均为植物特有的RdDM(RNA directed DNA methylation)通路中的核心组分,其中Pol IV在通路的上游协同RDR2一起生成前体siRNA,而Pol V则在下游产生lncRNA(long non-coding RNA)来招募DNA甲基转移酶从而引起基因组特定位点的基因沉默。因此与常规的DdR...
RNA Directed DNA Methylation (RdDM) is a pathway that mediates de novo DNA methylation, an evolutionary conserved chemical modification of cytosine bases, which exists in living organisms and utilizes small interfering RNA. Plants utilize DNA methylation for transposable element (TE) repression, ...
RNA聚合酶(DdRPs, DNA-dependent RNA polymerases) 是由多亚基组成的复合物,负责转录生成不同类型的RNA,是中心法则的核心执行者。除了所有真核生物中均保守的Pols I-III外,植物则拥有两种由Pol II进化而来的特化的DdRPs, Pol IV和Pol V。两者均为植物特有的RdDM (RNA directed DNA methylation) 通路中的核心组...
陆地植物通过RNA介导的DNA甲基化通路（RNA-directed DNA methylation pathway，RdDM）建立和部分维持基因组DNA甲基化。该通路中，基因组DNA甲基化与Pol V的转录延伸过程紧密偶联，Pol V转录延伸过程通过两个层次的相互作用招募Argonaute4/6-siRNA复合物。第一个层次是Pol V-KTF1和Argonaute 4/6蛋白的直接相互作用。该...
RNA-directed DNA methylation (RdDM) is the major small RNA-mediated epigenetic pathway in plants. RdDM requires a specialized transcriptional machinery that comprises two plant-specific RNA polymerases — Pol IV and Pol V — and a growing number of accessory proteins, the functions of which in th...
DNA甲基化在这些序列的建立都依赖于一条RNA介导的DNA甲基化(RNA-directed DNA methylation,RdDM)途径。RNA聚合酶Pol IV和Pol V在RdDM途径中分别负责产生小干扰RNA(small interfering RNAs,siRNAs)和长非编码RNA(Long Intergenic Noncoding RNAs, IGN RNAs)。siRNA和AGO4结合并与IGN RNA互补配对,招募甲基转移酶DRM2(...
► De novo DNA methylation in plants can be established by the RNA-directed DNA methylation (RdDM) pathway. ► RdDM involves biogenesis of siRNAs and scaffold RNAs, and the recruitment of DNA methyltransferase. ► RdDM process appears to be spatially and temporally segregated....
RNA导向的DNA甲基化(RdDM)途径是高等植物基因组甲基化的重要途径。在该途径中,植物独有的两个RNA聚合酶(Pol IV和Pol V)发挥了核心作用。Pol IV与RDR2合作产生小干扰RNA的dsRNA前体,经过加工后形成24个碱基的小干扰RNA,随后这些小干扰RNA在Argonaut蛋白的帮助下与RNA聚合酶Pol V产生的scaffold RNA配对,从而招募DNA...