Molecular structures and mechanisms of DNA break processing in mouse meiosis
- Shintaro Yamada1,2,
- Anjali Gupta Hinch3,
- Hisashi Kamido1,2,
- Yongwei Zhang4,
- Winfried Edelmann4 and
- Scott Keeney1,5
- 1Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA;
- 2Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan;
- 3Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, United Kingdom;
- 4Department of Cell Biology and Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
- 5Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
- Corresponding authors: s-keeney{at}ski.mskcc.org; yamada{at}rg.med.kyoto-u.ac.jp
Abstract
Exonucleolytic resection, critical to repair double-strand breaks (DSBs) by recombination, is not well understood, particularly in mammalian meiosis. Here, we define structures of resected DSBs in mouse spermatocytes genome-wide at nucleotide resolution. Resection tracts averaged 1100 nt, but with substantial fine-scale heterogeneity at individual hot spots. Surprisingly, EXO1 is not the major 5′ → 3′ exonuclease, but the DSB-responsive kinase ATM proved a key regulator of both initiation and extension of resection. In wild type, apparent intermolecular recombination intermediates clustered near to but offset from DSB positions, consistent with joint molecules with incompletely invaded 3′ ends. Finally, we provide evidence for PRDM9-dependent chromatin remodeling leading to increased accessibility at recombination sites. Our findings give insight into the mechanisms of DSB processing and repair in meiotic chromatin.
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Footnotes
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Supplemental material is available for this article.
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Article published online ahead of print. Aritcle and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.336032.119.
- Received December 15, 2019.
- Accepted March 25, 2020.
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