title: The fission yeast Crb2/Chk1 pathway coordinates the DNA damage and spindle checkpoint in response to replication stress induced by topoisomerase I inhibitor.
abstract: Living organisms experience constant threats that challenge their genome stability. The DNA damage checkpoint pathway coordinates cell cycle progression with DNA repair when DNA is damaged, thus ensuring faithful transmission of the genome. The spindle assembly checkpoint inhibits chromosome segregation until all chromosomes are properly attached to the spindle, ensuring accurate partition of the genetic material. Both the DNA damage and spindle checkpoint pathways participate in genome integrity. However, no clear connection between these two pathways has been described. Here, we analyze mutants in the BRCT domains of fission yeast Crb2, which mediates Chk1 activation, and provide evidence for a novel function of the Chk1 pathway. When the Crb2 mutants experience damaged replication forks upon inhibition of the religation activity of topoisomerase I, the Chk1 DNA damage pathway induces sustained activation of the spindle checkpoint, which in turn delays metaphase-to-anaphase transition in a Mad2-dependent fashion. This new pathway enhances cell survival and genome stability when cells undergo replicative stress in the absence of a proficient G(2)/M DNA damage checkpoint.
authors.affiliation: CNRS UMR 2027--Institut Curie, Bātiment 110, Centre Universitaire d'Orsay, France.
authors.forename: Ada
authors.initials: A
authors.lastname: Collura
authors.forename: Joel
authors.initials: J
authors.lastname: Blaisonneau
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Baldacci
authors.forename: Stefania
authors.initials: S
authors.lastname: Francesconi
mesh_terms: D000483:Alleles; D002166:Camptothecin / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D015825:Chromosomes, Fungal; D004249:DNA Damage / Q000187:drug effects*; D004261:DNA Replication / Q000187:drug effects*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics; D025141:Drug Resistance, Fungal; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D016681:Genome, Fungal; D064246:Mad2 Proteins; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D008941:Spindle Apparatus / Q000187:drug effects* / Q000378:metabolism; D059004:Topoisomerase I Inhibitors
chemical_list: D018797:Cell Cycle Proteins; C109867:Crb2 protein, S pombe; D004271:DNA, Fungal; D004791:Enzyme Inhibitors; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; D059004:Topoisomerase I Inhibitors; C577696:mad2 protein, S pombe; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C578636:Cds1 protein, S pombe; D000071877:Checkpoint Kinase 1; C000605873:Chk1 protein, S pombe; D017346:Protein Serine-Threonine Kinases; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin