DNA double-strand breaks impact genome stability by triggering many of the large-scale genome rearrangements associated with evolution and cancer. One of the first steps in repairing this damage is 5′→3′ resection beginning at the break site. Recently, tools have become available to study the consequences of not extensively resecting double-strand breaks. Here we examine the role of Sgs1 - and Exo1-dependent resection on genome stability using a non-selective assay that we previously developed using diploid yeast. We find that Saccharomyces cerevisiae lacking Sgs1 and Exo1 retains a very efficient repair process that is highly mutagenic to genome structure. Specifically, 51% of cells lacking Sgs1 and Exo1 repair a double-strand break using repetitive sequences 12–48 kb distal from the initial break site, thereby generating a genome rearrangement. These Sgs1 - and Exo1-independent rearrangements depend partially upon a Rad51-mediated homologous recombination pathway. Furthermore, without resection a robust cell cycle arrest is not activated, allowing a cell with a single double-strand break to divide before repair, potentially yielding multiple progeny each with a different rearrangement. This profusion of rearranged genomes suggests that cells tolerate any dangers associated with extensive resection to inhibit mutagenic pathways such as break-distal recombination. The activation of break-distal recipient repeats and amplification of broken chromosomes when resection is limited raise the possibility that genome regions that are difficult to resect may be hotspots for rearrangements. These results may also explain why mutations in resection machinery are associated with cancer.
Vyšlo v časopise: DNA Resection at Chromosome Breaks Promotes Genome Stability by Constraining Non-Allelic Homologous Recombination. PLoS Genet 8(3): e32767. doi:10.1371/journal.pgen.1002633 Kategorie: Research Article prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1002633
1. DeiningerPLBatzerMA 1999 Alu repeats and human disease. Mol Genet Metab 67 183 193
2. ZhangFGuWHurlesMELupskiJR 2009 Copy number variation in human health, disease, and evolution. Annu Rev Genomics Hum Genet 10 451 481
3. HillmerAMYaoFInakiKLeeWHAriyaratnePN 2011 Comprehensive long-span paired-end-tag mapping reveals characteristic patterns of structural variations in epithelial cancer genomes. Genome Res 21 665 675
4. KiddJMGravesTNewmanTLFultonRHaydenHS 2010 A human genome structural variation sequencing resource reveals insights into mutational mechanisms. Cell 143 837 847
5. UmezuKHiraokaMMoriMMakiH 2002 Structural analysis of aberrant chromosomes that occur spontaneously in diploid Saccharomyces cerevisiae: retrotransposon Ty1 plays a crucial role in chromosomal rearrangements. Genetics 160 97 110
6. PaquesFHaberJE 1999 Multiple pathways of recombination induced by double-strand breaks in Saccharomyces cerevisiae. Microbiol Mol Biol Rev 63 349 404
7. ChungWHZhuZPapushaAMalkovaAIraG 2010 Defective resection at DNA double-strand breaks leads to de novo telomere formation and enhances gene targeting. PLoS Genet 6 e1000948 doi:10.1371/journal.pgen.1000948
8. SugawaraNHaberJE 1992 Characterization of double-strand break-induced recombination: homology requirements and single-stranded DNA formation. Mol Cell Biol 12 563 575
9. GravelSChapmanJRMagillCJacksonSP 2008 DNA helicases Sgs1 and BLM promote DNA double-strand break resection. Genes Dev 22 2767 2772
10. MimitouEPSymingtonLS 2008 Sae2, Exo1 and Sgs1 collaborate in DNA double-strand break processing. Nature 455 770 774
11. ZhuZChungWHShimEYLeeSEIraG 2008 Sgs1 helicase and two nucleases Dna2 and Exo1 resect DNA double-strand break ends. Cell 134 981 994
12. HoangMLTanFJLaiDCCelnikerSEHoskinsRA 2010 Competitive repair by naturally dispersed repetitive DNA during non-allelic homologous recombination. PLoS Genet 6 e1001228 doi:10.1371/journal.pgen.1001228
13. MarreroVASymingtonLS 2010 Extensive DNA end processing by exo1 and sgs1 inhibits break-induced replication. PLoS Genet 6 e1001007 doi:10.1371/journal.pgen.1001007
14. LydeardJRLipkin-MooreZJainSEapenVVHaberJE 2010 Sgs1 and exo1 redundantly inhibit break-induced replication and de novo telomere addition at broken chromosome ends. PLoS Genet 6 e1000973 doi:10.1371/journal.pgen.1000973
15. IraGMalkovaALiberiGFoianiMHaberJE 2003 Srs2 and Sgs1-Top3 suppress crossovers during double-strand break repair in yeast. Cell 115 401 411
16. SugawaraNGoldfarbTStudamireBAlaniEHaberJE 2004 Heteroduplex rejection during single-strand annealing requires Sgs1 helicase and mismatch repair proteins Msh2 and Msh6 but not Pms1. Proc Natl Acad Sci U S A 101 9315 9320
17. MalkovaAIvanovELHaberJE 1996 Double-strand break repair in the absence of RAD51 in yeast: a possible role for break-induced DNA replication. Proc Natl Acad Sci U S A 93 7131 7136
18. LemoineFJDegtyarevaNPLobachevKPetesTD 2005 Chromosomal translocations in yeast induced by low levels of DNA polymerase a model for chromosome fragile sites. Cell 120 587 598
19. LambertSMizunoKBlaisonneauJMartineauSChanetR 2010 Homologous recombination restarts blocked replication forks at the expense of genome rearrangements by template exchange. Mol Cell 39 346 359
20. ZierhutCDiffleyJF 2008 Break dosage, cell cycle stage and DNA replication influence DNA double strand break response. EMBO J 27 1875 1885
21. VanHulleKLemoineFJNarayananVDowningBHullK 2007 Inverted DNA repeats channel repair of distant double-strand breaks into chromatid fusions and chromosomal rearrangements. Mol Cell Biol 27 2601 2614
22. ChenPLLiuFCaiSLinXLiA 2005 Inactivation of CtIP leads to early embryonic lethality mediated by G1 restraint and to tumorigenesis by haploid insufficiency. Mol Cell Biol 25 3535 3542
23. ChuWKHicksonID 2009 RecQ helicases: multifunctional genome caretakers. Nat Rev Cancer 9 644 654
Zvýšte si kvalifikáciu online z pohodlia domova
Nemáte účet? Registrujte sa
Zadajte e-mailovú adresu, s ktorou ste vytvárali účet. Budú Vám na ňu zasielané informácie k nastaveniu nového hesla.
