DNA methylation is a type of stable epigenetic modifications that plays crucial roles in regulating gene expression, silencing transposons and maintaining genome stability. In plants, the de novo DNA methylation is established via a pathway termed as RNA-directed DNA methylation (RdDM). The plant-specific DNA-dependent RNA polymerase IV (Pol IV) as the core protein in RdDM pathway produces non-coding RNAs that direct the establishment of DNA methylation, regulates gene expression and controls plant development. Pol IV function is regulated by several proteins including SHH1, which recognizes H3K9 methylation and guides Pol IV to genome specific sites, the chromatin remodeling factor CLSY family that is involved in assisting Pol IV chromatin association and RDR2 that converts Pol IV produced single-stranded RNA into double-stranded RNA. In this review, we summarize the latest progress on Pol IV and its co-regulators, and focus on their functions in shaping epigenome and development in plants, which might provide implications for studying of DNA methylation and crop breeding.
DNA甲基化是一类稳定可遗传的表观遗传修饰,在调控基因表达、沉默转座子和维持基因组稳定性等方面发挥重要作用。植物中,DNA从头甲基化通过RNA指导的DNA甲基化(RNA-directed DNA methylation, RdDM)途径建立。植物特有的DNA依赖的RNA聚合酶IV (DNA-dependent RNA polymerase IV, Pol IV)是RdDM途径核心蛋白,转录产生非编码RNA,通过RdDM途径引导从头建立DNA甲基化,进而调控植物基因表达和生长发育。Pol IV行使功能受多个蛋白调控：组蛋白阅读器SHH1 (SAWADEE homeodomain homolog 1)识别H3K9甲基化引导Pol IV到基因组特定位点;染色质重塑因子CLSY (CLASSY)蛋白家族协助Pol IV识别靶位点;RNA依赖的RNA聚合酶2 (RNA-dependent RNA polymerase 2, RDR2)将Pol IV转录产生的单链RNA转换成双链RNA。本文总结了Pol IV及其调控蛋白调控植物DNA甲基化和发育的研究进展,以期为DNA甲基化研究和农作物育种提供参考。.
Keywords: DNA methylation; Pol IV; RdDM pathway; development; epigenome.