Resolution of ROS‐induced G‐quadruplexes and R‐loops at transcriptionally active sites is dependent on BLM helicase
2020
Tan, Jun | Wang, Xiangyu | Phoon, Laiyee | Yang, Haibo | Lan, Li
R‐loops and G‐quadruplexes (G4s) are noncanonical secondary DNA structures. Here, we show that reactive oxygen species (ROS) induce G4 formation as well as R‐loops at transcriptionally active sites. Importantly, the G4 structure is subsequently triggered by R‐loop formation after damage. Once G4 is formed within an R‐loop, it reversely stabilizes the R‐loop. Notably, the helicase activity of Bloom syndrome protein is essential for the resolution of both R‐loops and G4s. Unresolved G4s and R‐loops delay the repair of ROS‐induced damage at actively transcribed sites. Together, our results demonstrate that interregulation between R‐loops and G4s induced by ROS is essential for repair at transcriptionally active sites.
显示更多 [+] 显示较少 [-]