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>The Arabidopsis RNA-Directed DNA Methylation Argonautes Functionally Diverge Based on Their Expression and Interaction with Target Loci
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The Arabidopsis RNA-Directed DNA Methylation Argonautes Functionally Diverge Based on Their Expression and Interaction with Target Loci
n nnnArgonaute (AGO) effectors of RNA silencing bind small RNA (sRNA)molecules and mediate mRNA cleavage, translational repression,or epigenetic DNA modification. In many organisms, these targetingmechanisms are devolved to different products of AGO multigenefamilies. To investigate the basis of AGO functional diversification,we characterized three closely related Arabidopsis thalianaAGOs (AGO4, AGO6, and AGO9) implicated in RNA-directed DNA methylation.All three AGOs bound 5' adenosine 24-nucleotide sRNAs, but eachexhibited different preferences for sRNAs from different heterochromatin-associatedloci. This difference was reduced when AGO6 and AGO9 were expressedfrom the AGO4 promoter, indicating that the functional diversificationwas partially due to differential expression of the correspondinggenes. However, the AGO4-directed pattern of sRNA accumulationand DNA methylation was not fully recapitulated with AGO6 orAGO9 expressed from the AGO4 promoter. Here, we show that sRNAlength and 5' nucleotide do not account for the observed functionaldiversification of these AGOs. Instead, the selectivity of sRNAbinding is determined by the coincident expression of the AGOand sRNA-generating loci, and epigenetic modification is influencedby interactions between the AGO protein and the different targetloci. These findings highlight the importance of tissue specificityand AGO-associated proteins in influencing epigenetic modifications.展开▼
机译:ABSTRACTn FONT> TH> TR> TABLE> n
n TOP n <字体颜色= 464c53>抽象 FONT> n 介绍 n 结果 n 讨论 n 方法 n 参考文献 n FONT> TH> TR> TABLE> n nnnArgonaute(AGO)RNA沉默效应子与小RNA(sRNA) SUP> mol结合Ecules并介导mRNA切割,翻译抑制, SUP>或表观遗传DNA修饰。在许多生物中,这些靶向 SUP>机制被转移到AGO多基因 SUP>家族的不同产品上。为了研究AGO功能多样化的基础,我们对与RNA-有牵连的三个紧密相关的拟南芥 I> SUP> AGO(AGO4,AGO6和AGO9)进行了表征。 SUP>所有三个AGO都结合5'腺苷24核苷酸sRNA,但每个 SUP>都对来自不同异染色质相关的 SUP> loci的sRNA表现出不同的偏好。从 AGO4 I>启动子表达 SUP>表示AGO6和AGO9时,这种差异减小了,这表明功能多样化 SUP>的部分原因是相应的差异表达。 SUP>基因。但是, AGO4 I>指导的sRNA积累 SUP>和DNA甲基化的模式并没有完全由 AGO4 < / I>启动子。在这里,我们显示sRNA SUP>的长度和5'核苷酸不能解释这些AGO的功能性 SUP>多样化。取而代之的是,sRNA SUP>结合的选择性取决于AGO SUP>和sRNA生成基因座的重合表达,而表观遗传修饰受相互作用的影响 SUP>在AGO蛋白和不同的目标 SUP>位置之间。这些发现强调了组织特异性 SUP>和与AGO相关的蛋白在影响表观遗传修饰中的重要性。 SUP>
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