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第一作者:Ben P Williams
第一单位:美国Whitehead生物医学研究所
第一通讯:Mary Gehring
Abstract
背景回顾:Cytosine methylation is a reversible epigenetic modification of DNA. In plants, removal of cytosine methylation is accomplished by the four members of the DEMETER (DME) family of 5-methylcytosine DNA glycosylases, named DME, DEMETER-LIKE2 (DML2), DML3, and REPRESSOR OF SILENCING1 (ROS1) in Arabidopsis thaliana. 提出问题:Demethylation by DME is critical for seed development, preventing experiments to determine the function of the entire gene family in somatic tissues by mutant analysis. 主要研究:Here, we bypassed the reproductive defects of dme mutants to create somatic quadruple homozygous mutants of the entire DME family. 结果1:dme; ros1; dml2; dml3 (drdd) leaves exhibit hypermethylated regions compared to wild-type leaves and rdd triple mutants, indicating functional redundancy among all four demethylases. 结果2:Targets of demethylation include regions co-targeted by RNA-directed DNA methylation and, surprisingly, CG gene body methylation, indicating dynamic methylation at these less-understood sites. 结果3:Additionally, many tissue-specific methylation differences are absent in drdd, suggesting a role for active demethylation in generating divergent epigenetic states across wild-type tissues. 结果4:Furthermore, drdd plants display an early flowering phenotype, which involves 5’ hypermethylation and transcriptional down-regulation of FLOWERING LOCUS C. 结论:Active DNA demethylation is therefore required for proper methylation across somatic tissues and defines the epigenetic landscape of intergenic and coding regions. 摘 要
胞嘧啶甲基化是DNA的可逆表观修饰。在拟南芥中,胞嘧啶甲基化的移除是由5-甲基胞嘧啶DNA糖基化酶DME家族的四个成员,即DME、DML2、DML3和ROS1来完成的。DME的去甲基化对种子的发育至关重要,这阻碍了通过突变来分析体细胞组织中整个基因家族的功能。本文中,作者绕过了dme突变的生殖缺陷,创制了整个DME家族的体细胞四突纯合体。与野生型和rdd三突植株的叶片相比,dme; ros1; dml2; dml3(drdd)四突植株的叶片存在高甲基化区域,表明所有四种去甲基酶之间存在功能冗余。去甲基化的靶标包括由RNA指导的DNA甲基化和CG基因体甲基化共靶向的区域,揭示了这些位点上的甲基化动态。此外,drdd四突中缺少许多组织特异性的甲基化差异,这表明野生型不同组织中活跃的去甲基化产生了不同的表观状态。此外,drdd四突植物表现出早花表型,这涉及了FLC基因的5'超甲基化和转录下调。因此,活跃的DNA去甲基化是体细胞组织适当甲基化所必需的,并决定了基因间和编码区的表观状态。
通讯作者
** Mary Gehring **
个人简介: 1998年,美国威廉姆斯学院,学士; 2005年,美国加州大学伯克利分校,博士。 研究方向:植物生殖发育过程中的表观遗传学。
doi: https://doi.org/10.1093/plcell/koab319
Journal: Plant Cell
Published date: December 25, 2021
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