biostudies-literatureMangione RMLigue Contre le CancerFondation ARC pour la Recherche sur le CancerFondation ARC pour la Recherche sur le Cancer (ARC Foundation for Cancer Research)Agence Nationale de la RechercheFondation pour la Recherche Médicale (Foundation for Medical Research in France)Agence Nationale de la Recherche (French National Research Agency)Fondation pour la Recherche MédicaleU.S. Department of Health & Human Services | National Institutes of Health (NIH)BioSPC PhD program Université Paris CitéNIGMS NIH HHSU.S. Department of Health & Human Services | National Institutes of Health2401https://www.ebi.ac.uk/biostudies/studies/S-EPMC11893903biostudies-literatureUnknown16(1)While DNA:RNA hybrids contribute to multiple genomic transactions, their unscheduled formation is a recognized source of DNA lesions. Here, through a suite of systematic screens, we rather observed that a wide range of yeast mutant situations primarily triggering DNA damage actually leads to hybrid accumulation. Focusing on Okazaki fragment processing, we establish that genic hybrids can actually form as a consequence of replication-born discontinuities such as unprocessed flaps or unligated Okazaki fragments. Strikingly, such "post-lesion" DNA:RNA hybrids neither detectably contribute to genetic instability, nor disturb gene expression, as opposed to "pre-lesion" hybrids formed upon defective mRNA biogenesis, e.g., in THO complex mutants. Post-lesion hybrids similarly arise in distinct geNature communicationsDNA lesions can frequently precede DNA:RNA hybrid accumulation.PMC11893903ANR-18-IDEX-0001GM50237FDT202304016590R35 GM118180ANR-21-CE12-0040EQU202003010245PJA20181208112RS21/75-21ANR-18-CE12-003ANR-11-LABX-0071de Almeida SFPierce SMangione RMGoncalves CReid RJDLancrey ALautier OZheng MPalancade BScaglione Sde Sousa Morgado CGaillard PHMartin RMPenzo AStirling PCKumar ARothstein RfalseDNA lesions can frequently precede DNA:RNA hybrid accumulation.While DNA:RNA hybrids contribute to multiple genomic transactions, their unscheduled formation is a recognized source of DNA lesions. Here, through a suite of systematic screens, we rather observed that a wide range of yeast mutant situations primarily triggering DNA damage actually leads to hybrid accumulation. Focusing on Okazaki fragment processing, we establish that genic hybrids can actually form as a consequence of replication-born discontinuities such as unprocessed flaps or unligated Okazaki fragments. Strikingly, such "post-lesion" DNA:RNA hybrids neither detectably contribute to genetic instability, nor disturb gene expression, as opposed to "pre-lesion" hybrids formed upon defective mRNA biogenesis, e.g., in THO complex mutants. Post-lesion hybrids similarly arise in distinct ge2025-01-01T00:00:00Z2025 Mar2026-06-01T18:02:04.644Z2025-04-04T00:21:44.243ZS-EPMC118939034006491410.1038/s41467-025-57588-x