Translation-coupled sensing and degradation of RNA-protein crosslinks [Ribo-Seq: dataset_2]

Reactive aldehydes are abundant cytotoxic metabolites, which challenge homoeostasis by crosslinking cellular macromolecules. Aldehyde-induced DNA-DNA crosslinks cause cancer and bone marrow failure in Fanconi anemia, while covalent DNA-protein crosslinks require proteolytic repair to prevent liver tumours and premature ageing. Whether RNA damage contributes to the toxicity of aldehydes and whether cells possess mechanisms to resolve RNA-protein crosslinks (RPCs) in particular is unknown. Studying the specific consequences of aldehyde-induced RNA damage is challenging due to confounding induction of DNA damage. Here, we establish photoactivatable ribonucleosides as a tractable model system to study aldehyde-mimicking RNA damage in the absence of DNA damage. We find that RNA crosslinking damage causes translational stress by stalling elongating ribosomes, which causes cell death upon ZAKα-dependent activation of the ribotoxic stress response (RSR) and GCN2-dependent activation of the integrated stress response (ISR). Moreover, we discover the principles of a translation-coupled cellular quality control mechanism that targets RPCs. Collisions between translating ribosomes and crosslinked mRNA-binding proteins trigger their ubiquitylation and subsequent proteasomal degradation. Our findings reveal RNA damage and RPC formation as a central aspect of aldehyde-induced toxicity and establish a framework to study the cellular responses to these threats in mechanistic detail. Ribosome profiling of two biological replicates of HAP1 cells with and without RNF14 knockout, treated with 4SU and UV and recovered for 0 or 30 min.