title: Mus81-Eme1 and Rqh1 involvement in processing stalled and collapsed replication forks.
abstract: The processing of stalled replication forks and the repair of collapsed replication forks are essential functions in all organisms. In fission yeast DNA junctions at stalled replication forks appear to be processed by either the Rqh1 DNA helicase or Mus81-Eme1 endonuclease. Accordingly, we show that the hypersensitivity to agents that cause replication fork stalling of mus81, eme1, and rqh1 mutants is suppressed by a Holliday junction resolvase (RusA), as is the synthetic lethality of a mus81(-) rqh1(-) double mutant. Recombinant Mus81-Eme1, purified from Escherichia coli, readily cleaves replication fork structures but cleaves synthetic Holliday junctions relatively poorly in vitro. From these data we propose that Mus81-Eme1 can process stalled replication forks before they have regressed to form a Holliday junction. We also implicate Mus81-Eme1 and Rqh1 in the repair of collapsed replication forks. Here Mus81-Eme1 and Rqh1 seem to function on different substrates because RusA can substitute for Mus81-Eme1 but not Rqh1.
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom.
authors.forename: Claudette L
authors.initials: CL
authors.lastname: Doe
authors.forename: Jong Sook
authors.initials: JS
authors.lastname: Ahn
authors.forename: Julie
authors.initials: J
authors.lastname: Dixon
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Whitby
mesh_terms: D002166:Camptothecin / Q000494:pharmacology; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis* / Q000378:metabolism; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D045565:Holliday Junction Resolvases; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D013379:Substrate Specificity; D014466:Ultraviolet Rays
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D004247:DNA; C442837:Eme1 protein, S pombe; D004706:Endodeoxyribonucleases; D004720:Endonucleases; C411624:MUS81 protein, S cerevisiae; D045565:Holliday Junction Resolvases; C112057:RusA protein, E coli; D004265:DNA Helicases; C106462:Rqh1 protein, S pombe; D002166:Camptothecin