Abstract
Sister chromatids are held together by cohesins. At anaphase, separase is activated by degradation of its inhibitory partner, securin. Separase then cleaves cohesins, thus allowing sister chromatid separation. Fission yeast securin (Cut2) has destruction boxes and a separase (Cut1) interaction site in the amino and carboxyl terminus, respectively. Here we show that securin is essential for separase stability and also for proper repair of DNA damaged by ultraviolet, X-ray and gamma-ray irradiation. The cut2(EA2) mutant is defective in the repair of ultraviolet damage lesions, although the DNA damage checkpoint is activated normally. In double mutant analysis of ultraviolet sensitivity, checkpoint kinase chk1 (ref. 9) and excision repair rad13 (ref. 10) mutants were additive with cut2(EA2), whereas recombination repair rhp51 (ref. 11) and cohesin subunit rad21 (ref. 12) mutants were not. Cohesin was hyper-modified on ultraviolet irradiation in a Rad3 kinase-dependent way. Experiments using either mutant cohesin that cannot be cleaved by separase or a protease-dead separase provide evidence that this DNA repair function of securin-separase acts through the cleavage of cohesin. We propose that the securin-separase complex might aid DNA repair by removing local cohesin in interphase cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Checkpoint Kinase 1
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Chromosomal Proteins, Non-Histone
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Chromosome Segregation
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Cohesins
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DNA Damage / radiation effects
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DNA Repair*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Endodeoxyribonucleases / genetics
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Endodeoxyribonucleases / metabolism
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Endopeptidases / genetics
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Endopeptidases / metabolism*
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Fungal Proteins
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Interphase*
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Mutation / genetics
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Phosphoproteins / chemistry
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Phosphoproteins / genetics
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Phosphoproteins / metabolism*
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Protein Kinases / genetics
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Protein Kinases / metabolism
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Protein Processing, Post-Translational
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Rad51 Recombinase
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Radiation Tolerance
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Schizosaccharomyces / cytology
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism*
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Schizosaccharomyces / radiation effects
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism*
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Securin
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Separase
Substances
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Cell Cycle Proteins
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Chromosomal Proteins, Non-Histone
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Cut1 protein, S pombe
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Cut2 protein, S pombe
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DNA-Binding Proteins
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Fungal Proteins
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Nuclear Proteins
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Phosphoproteins
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RHP51 protein, S pombe
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Rad21 protein, S pombe
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Schizosaccharomyces pombe Proteins
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Securin
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Protein Kinases
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Checkpoint Kinase 1
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Chk1 protein, S pombe
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Rad51 Recombinase
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Endodeoxyribonucleases
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Rad13 protein, S pombe
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Endopeptidases
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Separase