Abstract
Saccharomyces cells with one unrepaired double-strand break (DSB) adapt after checkpoint-mediated G2/M arrest. Adaptation is accompanied by loss of Rad53p checkpoint kinase activity and Chk1p phosphorylation. Rad53p kinase remains elevated in yku70delta and cdc5-ad cells that fail to adapt. Permanent G2/M arrest in cells with increased single-stranded DNA is suppressed by the rfa1-t11 mutation, but this RPA mutation does not suppress permanent arrest in cdc5-ad cells. Checkpoint kinase activation and inactivation can be followed in G2-arrested cells, but there is no kinase activation in G1-arrested cells. We conclude that activation of the checkpoint kinases in response to a single DNA break is cell cycle regulated and that adaptation is an active process by which these kinases are inactivated.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptation, Biological / genetics*
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Anaphase
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Antigens, Nuclear*
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Cycle*
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Checkpoint Kinase 1
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Checkpoint Kinase 2
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DNA Damage / genetics*
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DNA Helicases*
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DNA, Fungal / metabolism
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Enzyme Activation
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Fungal Proteins / metabolism
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G2 Phase
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Gene Expression
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Intracellular Signaling Peptides and Proteins
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Kinetics
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Ku Autoantigen
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Mitosis
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Mutation
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Phosphorylation
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Protein Kinases / metabolism*
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Protein Serine-Threonine Kinases*
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RNA-Binding Proteins
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Recombination, Genetic
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Replication Protein A
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Saccharomyces cerevisiae / cytology
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins*
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Sequence Homology, Nucleic Acid
Substances
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Antigens, Nuclear
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CEF1 protein, S cerevisiae
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Cell Cycle Proteins
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DNA, Fungal
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DNA-Binding Proteins
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Fungal Proteins
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Intracellular Signaling Peptides and Proteins
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Nuclear Proteins
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RNA-Binding Proteins
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Replication Protein A
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Saccharomyces cerevisiae Proteins
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high affinity DNA-binding factor, S cerevisiae
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Protein Kinases
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Checkpoint Kinase 2
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Checkpoint Kinase 1
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MEC1 protein, S cerevisiae
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Protein Serine-Threonine Kinases
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RAD53 protein, S cerevisiae
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DNA Helicases
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XRCC5 protein, human
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Xrcc6 protein, human
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Ku Autoantigen