1. Senataxin Ortholog Sen1 Limits DNA:RNA Hybrid Accumulation at DNA Double-Strand Breaks to Control End Resection and Repair Fidelity
- Author
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Chetan C. Rawal, Luca Zardoni, Matteo Di Terlizzi, Elena Galati, Alessandra Brambati, Federico Lazzaro, Giordano Liberi, and Achille Pellicioli
- Subjects
DSB resection ,DSB repair ,Sen1/Senataxin ,DNA:RNA hybrid ,Mre11 ,Dna2 ,Biology (General) ,QH301-705.5 - Abstract
Summary: An important but still enigmatic function of DNA:RNA hybrids is their role in DNA double-strand break (DSB) repair. Here, we show that Sen1, the budding yeast ortholog of the human helicase Senataxin, is recruited at an HO endonuclease-induced DSB and limits the local accumulation of DNA:RNA hybrids. In the absence of Sen1, hybrid accumulation proximal to the DSB promotes increased binding of the Ku70-80 (KU) complex at the break site, mutagenic non-homologous end joining (NHEJ), micro-homology-mediated end joining (MMEJ), and chromosome translocations. We also show that homology-directed recombination (HDR) by gene conversion is mostly proficient in sen1 mutants after single DSB. However, in the absence of Sen1, DNA:RNA hybrids, Mre11, and Dna2 initiate resection through a non-canonical mechanism. We propose that this resection mechanism through local DNA:RNA hybrids acts as a backup to prime HDR when canonical pathways are altered, but at the expense of genome integrity.
- Published
- 2020
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