tRNA-derived small non-coding RNAs perturb C. elegans gene expression in response to genotoxic stress.

Research shows that the individual lifestyle and environment of an organism can influence its phenotype and potentially the phenotype of its offspring. The different genetic and non-genetic components of the inheritance system and their mutual interactions are key mechanisms to generate inherited phenotypic changes. Epigenetic changes can be transmitted between generations independently from changes in DNA sequence. In C. elegans, epigenetic differences, i.e., epimutations, mediated by small non-coding RNAs, particularly 22G RNAs, as well as chromatin have been identified and their average persistence is 3 to 5 generations. In addition, previous research showed that some epimutations had a longer duration and concerned genes that were enriched for multiple components of xenobiotic response pathways. These results raise the possibility that environmental stresses might change the rate at which epimutations occur, with potential significance for adaptation. In this work, we explore this question by propagating C. elegans lines either in control conditions or in moderate or high doses of the chemical cisplatin, which introduces genotoxic stress by damaging DNA. Our results show that cisplatin has a limited effect on global small non-coding RNAs epimutations but does affect epimutation rate on tRNAs 3 prime halves. Such changes in tRNAs fragments may impact genes expression. This result echo recent advances in environmental epigenetic suggesting tRNAs as potentials new epigenetic regulators in multi/transgenerational inheritance and offspring adaptation.