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Science. 2015 Aug 14;349(6249):742-7. doi: 10.1126/science.aaa8391.

DNA REPAIR. Mus81 and converging forks limit the mutagenicity of replication fork breakage.

Author information

1
Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
2
Department of Molecular Biology and Genetics, University of Aarhus, Aarhus 8000, Denmark.
3
Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. Department of Pediatrics, and Human Genome Sequencing Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. Texas Children's Hospital, Houston, TX 77030, USA.
4
Department of Molecular and Human Genetics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA. gira@bcm.edu.

Abstract

Most spontaneous DNA double-strand breaks (DSBs) result from replication-fork breakage. Break-induced replication (BIR), a genome rearrangement-prone repair mechanism that requires the Pol32/POLD3 subunit of eukaryotic DNA Polδ, was proposed to repair broken forks, but how genome destabilization is avoided was unknown. We show that broken fork repair initially uses error-prone Pol32-dependent synthesis, but that mutagenic synthesis is limited to within a few kilobases from the break by Mus81 endonuclease and a converging fork. Mus81 suppresses template switches between both homologous sequences and diverged human Alu repetitive elements, highlighting its importance for stability of highly repetitive genomes. We propose that lack of a timely converging fork or Mus81 may propel genome instability observed in cancer.

PMID:
26273056
PMCID:
PMC4782627
DOI:
10.1126/science.aaa8391
[Indexed for MEDLINE]
Free PMC Article

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