RNA聚合酶Ⅱ
终止因子
抄写(语言学)
过程性
聚合酶
细胞生物学
转录泡
RNA聚合酶
转录因子ⅡD
生物
编码链
核糖核酸
DNA
遗传学
化学
RNA依赖性RNA聚合酶
基因
发起人
基因表达
哲学
语言学
作者
Guohui Xie,Xuan Du,Hongmiao Hu,Sisi Li,Xiaofeng Cao,Steven E. Jacobsen,Jiamu Du
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:2023-03-24
卷期号:379 (6638): 1209-1213
被引量:9
标识
DOI:10.1126/science.adf8231
摘要
In addition to the conserved RNA polymerases I to III (Pols I to III) in eukaryotes, two atypical polymerases, Pols IV and V, specifically produce noncoding RNA in the RNA-directed DNA methylation pathway in plants. Here, we report on the structures of cauliflower Pol V in the free and elongation conformations. A conserved tyrosine residue of NRPE2 stacks with a double-stranded DNA branch of the transcription bubble to potentially attenuate elongation by inducing transcription stalling. The nontemplate DNA strand is captured by NRPE2 to enhance backtracking, thereby increasing 3'-5' cleavage, which likely underpins Pol V's high fidelity. The structures also illuminate the mechanism of Pol V transcription stalling and enhanced backtracking, which may be important for Pol V's retention on chromatin to serve its function in tethering downstream factors for RNA-directed DNA methylation.
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