The multiple layers of RNA response in double-strand break repair.

RNA molecules are now recognized as active regulators of DNA double-strand break repair. In end-joining pathways, nascent transcripts promote repair through RNA:DNA hybrids, end bridging and RNA-templated synthesis. In homologous recombination, RNA:DNA hybrids modulate DNA end resection, recruit repair factors and enable RNA-templated repair, with DNA polymerase ζ emerging as a key reverse transcriptase in this process. Transcription at double-strand break sites generates regulatory RNAs that further influence pathway choice and repair fidelity. Long noncoding RNAs, RNA-binding proteins and RNA modifications add additional control layers. Advances in genomic mapping, reporter assays and in vitro methods are now dissecting these complex RNA-mediated processes, although important challenges remain in capturing their full kinetics and contributions. Finally, RNA-templated genome editing platforms, such as prime editing, harness these principles for precise, programmable DNA repair. Together, these findings position RNA as a multifunctional player in genome maintenance and engineering.