title: The DNA damage checkpoint pathway promotes extensive resection and nucleotide synthesis to facilitate homologous recombination repair and genome stability in fission yeast.
abstract: DNA double-strand breaks (DSBs) can cause chromosomal rearrangements and extensive loss of heterozygosity (LOH), hallmarks of cancer cells. Yet, how such events are normally suppressed is unclear. Here we identify roles for the DNA damage checkpoint pathway in facilitating homologous recombination (HR) repair and suppressing extensive LOH and chromosomal rearrangements in response to a DSB. Accordingly, deletion of Rad3(ATR), Rad26ATRIP, Crb2(53BP1) or Cdc25 overexpression leads to reduced HR and increased break-induced chromosome loss and rearrangements. We find the DNA damage checkpoint pathway facilitates HR, in part, by promoting break-induced Cdt2-dependent nucleotide synthesis. We also identify additional roles for Rad17, the 9-1-1 complex and Chk1 activation in facilitating break-induced extensive resection and chromosome loss, thereby suppressing extensive LOH. Loss of Rad17 or the 9-1-1 complex results in a striking increase in break-induced isochromosome formation and very low levels of chromosome loss, suggesting the 9-1-1 complex acts as a nuclease processivity factor to facilitate extensive resection. Further, our data suggest redundant roles for Rad3ATR and Exo1 in facilitating extensive resection. We propose that the DNA damage checkpoint pathway coordinates resection and nucleotide synthesis, thereby promoting efficient HR repair and genome stability.
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Blaikley
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Tinline-Purvis
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Torben R
authors.initials: TR
authors.lastname: Kasparek
authors.affiliation: Department of Genetics, Evolution and Environment, and UCL Cancer Institute, University College London, London WC1E 6BT, UK.
authors.forename: Samuel
authors.initials: S
authors.lastname: Marguerat
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Sovan
authors.initials: S
authors.lastname: Sarkar
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Lydia
authors.initials: L
authors.lastname: Hulme
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Sharon
authors.initials: S
authors.lastname: Hussey
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Boon-Yu
authors.initials: BY
authors.lastname: Wee
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Rachel S
authors.initials: RS
authors.lastname: Deegan
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Carol A
authors.initials: CA
authors.lastname: Walker
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Chen-Chun
authors.initials: CC
authors.lastname: Pai
authors.affiliation: Department of Genetics, Evolution and Environment, and UCL Cancer Institute, University College London, London WC1E 6BT, UK.
authors.forename: Jürg
authors.initials: J
authors.lastname: Bähler
authors.affiliation: Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka 560-0043, Osaka, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: CRUK-MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, OX3 7DQ, UK.
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Humphrey
mesh_terms: D059447:Cell Cycle Checkpoints; D064447:Checkpoint Kinase 2 / Q000378:metabolism; D015825:Chromosomes, Fungal / Q000235:genetics; D055028:Comparative Genomic Hybridization; D053903:DNA Breaks, Double-Stranded; D053837:DNA Cleavage; D005090:Exodeoxyribonucleases / Q000378:metabolism; D016681:Genome, Fungal; D042822:Genomic Instability; D019656:Loss of Heterozygosity; D009711:Nucleotides / Q000096:biosynthesis; D059767:Recombinational DNA Repair; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism
chemical_list: D009711:Nucleotides; D029702:Schizosaccharomyces pombe Proteins; D064447:Checkpoint Kinase 2; C456840:rad3 protein, S pombe; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I