Abstract
In an effort to identify novel genes involved in recombination repair, we isolated fission yeast Schizosaccharomyces pombe mutants sensitive to methyl methanesulfonate (MMS) and a synthetic lethal with rad2. A gene that complements such mutations was isolated from the S. pombe genomic library, and subsequent analysis identified it as the fbh1 gene encoding the F-box DNA helicase, which is conserved in mammals but not conserved in Saccharomyces cerevisiae. An fbh1 deletion mutant is moderately sensitive to UV, MMS, and gamma rays. The rhp51 (RAD51 ortholog) mutation is epistatic to fbh1. fbh1 is essential for viability in stationary-phase cells and in the absence of either Srs2 or Rqh1 DNA helicase. In each case, lethality is suppressed by deletion of the recombination gene rhp57. These results suggested that fbh1 acts downstream of rhp51 and rhp57. Following UV irradiation or entry into the stationary phase, nuclear chromosomal domains of the fbh1Delta mutant shrank, and accumulation of some recombination intermediates was suggested by pulsed-field gel electrophoresis. Focus formation of Fbh1 protein was induced by treatment that damages DNA. Thus, the F-box DNA helicase appears to process toxic recombination intermediates, the formation of which is dependent on the function of Rhp51.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / genetics
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Cell Nucleus / chemistry
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Cell Nucleus / metabolism
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DNA Damage / genetics
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DNA Helicases / analysis
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DNA Helicases / genetics
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DNA Helicases / physiology*
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DNA Repair / genetics*
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DNA, Fungal / drug effects
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DNA, Fungal / metabolism
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DNA, Fungal / radiation effects
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DNA-Binding Proteins / analysis
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Drug Resistance / genetics
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F-Box Proteins / genetics
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F-Box Proteins / physiology*
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Gamma Rays
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Gene Deletion
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Genes, Lethal / genetics
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Genes, Lethal / physiology
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Methyl Methanesulfonate / pharmacology
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Mutation
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Nuclear Proteins / genetics
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Rad51 Recombinase
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Recombination, Genetic / genetics*
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Schizosaccharomyces / drug effects
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Schizosaccharomyces / enzymology
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Schizosaccharomyces / genetics*
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Schizosaccharomyces pombe Proteins / analysis
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism
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Schizosaccharomyces pombe Proteins / physiology*
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Ultraviolet Rays
Substances
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DNA, Fungal
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DNA-Binding Proteins
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F-Box Proteins
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Nuclear Proteins
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RHP51 protein, S pombe
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Schizosaccharomyces pombe Proteins
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Rad15 protein, S pombe
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Methyl Methanesulfonate
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Rad51 Recombinase
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Adenosine Triphosphatases
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Rhp57 protein, S pombe
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DNA Helicases
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Fbh1 protein, S pombe
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Srs2 protein, S pombe