A role for R-Loops in promoting antisense transcription

A role for R-Loops in promoting antisense transcription

R-Loops are nucleic acid structures that have been implicated in both DNA damage and DNA repair processes. They tend to form during transcription, when a growing RNA strand invades the DNA to form an RNA:DNA hybrid. R-Loops contain single-stranded DNA, a type of DNA which has been shown to possess the potential to initiate transcription.

By forming these structures in vitro, researchers from the Proudfoot Lab demonstrated that R-Loops are indeed able to promote transcription. The team then moved into cells to find out what sort of transcripts these R-Loops might be initiating. When they removed the R-Loops using a specific enzyme called RNase H1, they found that levels of antisense long non-coding RNAs (lncRNA) were reduced when compared with cells which had not been expressing the RNase. Furthermore, the researchers showed that these RNase-sensitive lncRNA transcripts were often formed adjacent to R-Loops, suggesting that their formation is R-Loop dependent.

lncRNA may form from protein-coding genes but do not code for proteins themselves. Their function is enigmatic, and little was previously known about how lncRNA are produced. This study offers insight into their origin, as well as positing a novel function for R-Loops in our genome.

Laura Hankins

Tan-Wong SM, Dhir S, Proudfoot NJ (2019).

Mol. Cell 76(4):600-616.e6