RHON1 Co-transcriptionally Resolves R-Loops for Arabidopsis Chloroplast Genome Maintenance
RHON1 Co-transcriptionally Resolves R-Loops for Arabidopsis Chloroplast Genome Maintenance
复制标题
RHON1 共转录解决拟南芥叶绿体基因组维护的 R 环
DOI：
10.1016/j.celrep.2019.12.007
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发表时间：
2020
期刊：
影响因子：
8.8
通讯作者：
Qianwen Sun
中科院分区：
文献类型：
--
作者：
Zhuo Yang;Mengmeng Li;Qianwen Sun
防止转录复制正面冲突 (HO-TRC) 触发的 R 环形成对于维持细菌、植物和哺乳动物基因组完整性至关重要。 R环擦除器RNase H可以有效地松弛HO-TRC。然而，当 RNase H 蛋白缺乏时，尚不清楚生物体如何抵抗 HO-TRC 触发的 R 环。通过筛选可能缓解拟南芥atrnh1突变体中R环积累的因子，我们发现R环解旋酶RHON1的过度表达可以挽救HO-TRC触发的R环共转录异常积累的缺陷。此外，我们发现 RHON1 与质体编码的 RNA 聚合酶的转录活性相互作用并协调，以缓解转录和复制之间的冲突。我们的研究表明，生物体采用多种机制来逃避 HO-TRC 触发的 R 环积累，从而维持基因组完整性。
Preventing transcription-replication head-on conflict (HO-TRC)-triggered R-loop formation is essential for maintaining genome integrity in bacteria, plants, and mammals. The R-loop eraser RNase H can efficiently relax HO-TRCs. However, it is not clear how organisms resist HO-TRC-triggered R-loops when RNase H proteins are deficient. By screening factors that may relieve R-loop accumulation in theArabidopsis atrnh1cmutant, we find that overexpression of the R-loop helicase RHON1 can rescue the defects of aberrantly accumulated HO-TRC-triggered R-loops co-transcriptionally. In addition, we find that RHON1 interacts with and orchestrates the transcriptional activity of plastid-encoded RNA polymerases to release the conflicts between transcription and replication. Our study illustrates that organisms employ multiple mechanisms to escape HO-TRC-triggered R-loop accumulation and thus maintain genome integrity.