Fig. 2

The structure of the R-loop and the process of transcription-replication conflicts. a R-loop is a three-stranded nucleic acid structure consisting of an RNA: DNA hybrid strand and a replaced DNA strand (ssDNA). b In the S phase of the cell cycle, transcription and replication share the same DNA strand as a template, which makes the two processes often collide. The transcription-replication conflict is divided into two types: HO and CD conflict. In the HO conflict, RNA polymerase II collides with the replicon, which leads to the generation of the R-loop. The consequences of co-directional conflict are different from those of HO conflict, which can avoid the accumulation of the R-loop