R-loops have both positive and negative impacts on chromosome functions. To identify toxic R-loops, we mapped RNA:DNA hybrids, markers of replication fork stalling and DNA double-strand breaks along the human genome. This analysis indicates that transient replication fork pausing occurs at the transcription termination sites of highly expressed genes enriched in R-loops and prevents head-on conflicts with transcription, in a topoisomerase I-dependent manner.
Keywords: R-loops; Transcription-replication conflict; chromosome breaks; topoisomerase I.
© 2020 The Author(s). Published with license by Taylor & Francis Group, LLC.