m6A modification in R-loop homeostasis: a potential target for cancer therapeutics

R-loops or DNA-RNA hybrids are prominent nucleic acid structures that commonly arise during transcription. These structures play important biological functions, such as regulating gene expression and DNA repair. However, when unresolved by nucleic acid processing factors, pathological R-loops can be harmful and lead to genome instability. N ⁶-Methyladenosine (m6A), the most prevalent modification in messenger RNA, has been recently identified to be crucial for regulating R-loop balance and maintaining genome stability. Strikingly, m6A-modified R-loop formation can have opposing consequences, either stabilization or resolution, depending on the biological context. In this review, we discuss the current knowledge of the regulatory roles of m6A on R-loops across various processes, including gene transcription, DNA repair, and centromere and telomere stability. Additionally, we explore other m6A-mediated processes, such as nascent transcription and chromatin landscape, that potentially affect R-loop dynamics. Finally, we discuss the current limitations and future directions of studying the m6A-R-loop axis, as well as the opportunities to target this pathway as a potential therapeutic strategy.