DNA-RNA hybrids at DSBs interfere with repair by homologous recombination
- CABIMER, Universidad de Sevilla, Spain
Abstract
DNA double strand breaks (DSBs) are the most harmful DNA lesions and their repair is crucial for cell viability and genome integrity. The readout of DSB repair may depend on whether DSBs occur at transcribed versus non-transcribed regions. Some studies have postulated that DNA-RNA hybrids form at DSBs to promote recombinational repair, but others have challenged this notion. To directly assess whether hybrids formed at DSBs promote or interfere with recombinational repair we have used plasmid and chromosomal-based systems for the analysis of DSB-induced recombination in Saccharomyces cerevisiae. We show that, as expected, DNA-RNA hybrid formation is stimulated at DSBs. In addition, mutations that promote DNA-RNA hybrid accumulation, such as hpr1∆ and rnh1∆ rnh201∆, cause high levels of plasmid loss when DNA breaks are induced at sites that are transcribed. Importantly, we show that high levels or unresolved DNA-RNA hybrids at the breaks interfere with their repair by homologous recombination. This interference is observed for both plasmid and chromosomal recombination and is independent of whether the DSB is generated by endonucleolytic cleavage or by DNA replication. These data support a model in which DNA-RNA hybrids form fortuitously at DNA breaks during transcription, and need to be removed to allow recombinational repair, rather than playing a positive role.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for all figures.
Article and author information
Author details
Belén Gómez-González
Funding
H2020 European Research Council (ERC2014 AdG669898 TARLOOP)
- Andrés Aguilera
Ministerio de Economía y Competitividad (BFU2016-75058-P)
- Andrés Aguilera
Ministerio de Ciencia, Innovación y Universidades (PDI2019-104270GB-I00)
- Andrés Aguilera
Junta de Andalucía (P12-BIO-1238)
- Andrés Aguilera
European Union, FEDER
- Andrés Aguilera
Ministerio de Educación, Cultura y Deporte (PhD FPU fellowship)
- Pedro Ortega
Junta de Andalucía (PhD fellowship)
- Jose Antonio Mérida-Cerro
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Ortega et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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DNA-RNA hybrids at DSBs interfere with repair by homologous recombination
eLife 10:e69881.
https://doi.org/10.7554/eLife.69881
