title: Production of reactive oxygen species in response to replication stress and inappropriate mitosis in fission yeast.
abstract: Previous studies have indicated that replication stress can trigger apoptosis-like cell death, accompanied (where tested) by production of reactive oxygen species (ROS), in mammalian cells and budding yeast (Saccharomyces cerevisiae). In mammalian cells, inappropriate entry into mitosis also leads to cell death. Here, we report similar responses in fission yeast (Schizosaccharomyces pombe). We used ROS- and death-specific fluorescent stains to measure the effects of mutations in replication initiation and checkpoint genes in fission yeast on the frequencies of ROS production and cell death. We found that certain mutant alleles of each of the four tested replication initiation genes caused elevated ROS and cell death. Where tested, these effects were not enhanced by checkpoint-gene mutations. Instead, when cells competent for replication but defective in both the replication and damage checkpoints were treated with hydroxyurea, which slows replication fork movement, the frequencies of ROS production and cell death were greatly increased. This was a consequence of elevated CDK activity, which permitted inappropriate entry into mitosis. Thus, studies in fission yeast are likely to prove helpful in understanding the pathways that lead from replication stress and inappropriate mitosis to cell death in mammalian cells.
authors.affiliation: Department of Cancer Genetics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Marchetti
authors.forename: Martin
authors.initials: M
authors.lastname: Weinberger
authors.forename: Yota
authors.initials: Y
authors.lastname: Murakami
authors.forename: William C
authors.initials: WC
authors.lastname: Burhans
authors.forename: Joel A
authors.initials: JA
authors.lastname: Huberman
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000502:physiology; D002455:Cell Division / Q000502:physiology*; D004261:DNA Replication; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D018816:Genes, cdc; D006801:Humans; D006918:Hydroxyurea / Q000378:metabolism; D008938:Mitosis / Q000502:physiology*; D009154:Mutation; D019384:Nucleic Acid Synthesis Inhibitors / Q000378:metabolism; D051738:Origin Recognition Complex / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000166:cytology / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C110400:2',7'-dichlorodihydrofluorescein diacetate; D018797:Cell Cycle Proteins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D019384:Nucleic Acid Synthesis Inhibitors; D051738:Origin Recognition Complex; D017382:Reactive Oxygen Species; D029702:Schizosaccharomyces pombe Proteins; C082462:cdc18 protein, S pombe; C097704:orc2 protein, S pombe; D006918:Hydroxyurea