Multistep mechanism of DNA replication-coupled G-quadruplex resolution
biorxiv(2020)
摘要
G-quadruplex (or G4) structures are non-canonical DNA structures that form in guanine-rich sequences and threaten genome stability when not properly resolved. G4 unwinding occurs during S phase via an unknown mechanism. Using Xenopus egg extracts, we define a three-step G4 unwinding mechanism that is coupled to DNA replication. First, the replicative helicase (CMG) stalls at a leading strand G4 structure. Second, the DHX36 helicase mediates the bypass of the CMG past the intact G4 structure, which allows approach of the leading strand to the G4. Third, G4 structure unwinding by the FANCJ helicase enables the DNA polymerase to synthesize past the G4 motif. A G4 on the lagging strand template does not stall CMG, but still requires DNA replication for unwinding. DHX36 and FANCJ have partially redundant roles, conferring robustness to this pathway. Our data reveal a novel genome maintenance pathway that promotes faithful G4 replication thereby avoiding genome instability.
### Competing Interest Statement
The authors have declared no competing interest.
更多查看译文
关键词
multistep mechanism,resolution,replication-coupled,g-quadruplex
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要