Abstract
The signaling cascade initiated in response to DNA double-strand breaks (DSBs) has been extensively investigated in interphase cells. Here, we show that mitotic cells treated with DSB-inducing agents activate a "primary" DNA damage response (DDR) comprised of early signaling events, including activation of the protein kinases ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PK), histone H2AX phosphorylation together with recruitment of mediator of DNA damage checkpoint 1 (MDC1), and the Mre11-Rad50-Nbs1 (MRN) complex to damage sites. However, mitotic cells display no detectable recruitment of the E3 ubiquitin ligases RNF8 and RNF168, or accumulation of 53BP1 and BRCA1, at DSB sites. Accordingly, we found that DNA-damage signaling is attenuated in mitotic cells, with full DDR activation only ensuing when a DSB-containing mitotic cell enters G1. Finally, we present data suggesting that induction of a primary DDR in mitosis is important because transient inactivation of ATM and DNA-PK renders mitotic cells hypersensitive to DSB-inducing agents.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Ataxia Telangiectasia Mutated Proteins
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Line
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DNA Breaks, Double-Stranded*
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DNA Damage*
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DNA Repair
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DNA-Activated Protein Kinase / genetics
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DNA-Activated Protein Kinase / metabolism
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Histones / genetics
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Histones / metabolism
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Humans
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Intracellular Signaling Peptides and Proteins / genetics
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Intracellular Signaling Peptides and Proteins / metabolism
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Mitosis / physiology*
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Signal Transduction / physiology*
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Trans-Activators / genetics
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Trans-Activators / metabolism
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / metabolism
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Tumor Suppressor p53-Binding Protein 1
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Ubiquitin-Protein Ligases / genetics
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Ubiquitin-Protein Ligases / metabolism
Substances
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Adaptor Proteins, Signal Transducing
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Cell Cycle Proteins
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DNA-Binding Proteins
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H2AX protein, human
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Histones
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Intracellular Signaling Peptides and Proteins
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MDC1 protein, human
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Nuclear Proteins
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RNF8 protein, human
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Recombinant Fusion Proteins
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TP53BP1 protein, human
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Trans-Activators
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Tumor Suppressor Proteins
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Tumor Suppressor p53-Binding Protein 1
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RNF168 protein, human
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Ubiquitin-Protein Ligases
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ATM protein, human
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Ataxia Telangiectasia Mutated Proteins
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DNA-Activated Protein Kinase
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PRKDC protein, human
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Protein Serine-Threonine Kinases