Homologous recombination (HR), the high-fidelity mechanism for double-strand break (DSB) repair, relies on DNA end resection by nucleolytic degradation of the 5¢-terminated ends. However, the role of long-range resection mediated by Exo1 and/or Sgs1-Dna2 in HR is not fully understood. Here, we show that Exo1 and Sgs1 are dispensable for recombination between closely-linked repeats, but are required for interchromosomal repeat recombination in Saccharomyces cerevisiae. This context-specific requirement for long-range end resection is connected to its role in activating the DNA damage checkpoint. Consistent with this role, checkpoint mutants also show a defect specifically in interchromosomal recombination. Furthermore, artificial activation of the checkpoint partially restores interchromosomal recombination to exo1∆ sgs1∆ cells. However, cell cycle delay is insufficient to rescue the interchromosomal recombination defect of exo1∆ sgs1∆ cells, suggesting an additional role for the checkpoint. Given that the checkpoint is necessary for DNA damage-induced chromosome mobility, we propose that the importance of the checkpoint, and therefore long-range resection, in interchromosomal recombination is due to a need to increase chromosome mobility to facilitate pairing of distant sites. The need for long-range resection is circumvented when the DSB and its repair template are in close proximity.
All data generated or analyzed during this study are included in the manuscript and supporting files; Source data files have been provided for Figures 1-5 and Supplementary Figures 1-6
- Michael T Kimble
- Matthew J Johnson
- Mattie R Nester
- Lorraine S Symington
- Michael T Kimble
- Matthew J Johnson
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Andrés Aguilera, CABIMER, Universidad de Sevilla, Spain
© 2023, Kimble 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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