Epitranscriptome in action: RNA modifications in the DNA damage response.

Complex pathways involving the DNA damage response (DDR) contend with cell-intrinsic and -extrinsic sources of DNA damage. DDR mis-regulation results in genome instability that can contribute to aging and diseases including cancer and neurodegeneration. Recent studies have highlighted key roles for several RNA species in the DDR, including short RNAs and RNA/DNA hybrids (R-loops) at DNA break sites, all contributing to efficient DNA repair. RNAs can undergo more than 170 distinct chemical modifications. These RNA modifications have emerged as key orchestrators of the DDR. Here, we highlight the function of enzyme- and non-enzyme-induced RNA modifications in the DDR, with particular emphasis on mA, mC, and RNA editing. We also discuss stress-induced RNA damage, including RNA alkylation/oxidation, RNA-protein crosslinks, and UV-induced RNA damage. Uncovering molecular mechanisms that underpin the contribution of RNA modifications to DDR and genome stability will have direct application to disease and approaches for therapeutic intervention.