Abstract
Exposure of mammalian cells to DNA damage-inducing agents (DDIA) inhibits ongoing DNA replication. The molecular mechanism of this inhibition remains to be elucidated. We employed a simian virus 40 (SV40) based in vitro DNA replication assay to study biochemical aspects of this inhibition. We report here that the reduced DNA replication activity in extracts of DDIA-treated cells is partly caused by a reduction in the amount of replication protein A (RPA). We also report that the dominant inhibitory effect is caused by the DNA-dependent protein kinase (DNA-PK) which inactivates SV40 T antigen (TAg) by phosphorylation. The results demonstrate that RPA and DNA-PK are involved in the regulation of viral DNA replication after DNA damage and suggest that analogous processes regulate cellular DNA replication with the DNA-PK targeting the functional homologues of TAg.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Androstadienes / pharmacology
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Antigens, Polyomavirus Transforming / metabolism
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Camptothecin / pharmacology
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Cytoplasm / metabolism
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DNA Damage*
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DNA Replication* / drug effects
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DNA Replication* / radiation effects
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DNA, Viral / drug effects
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DNA, Viral / genetics*
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DNA, Viral / radiation effects
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DNA-Activated Protein Kinase
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DNA-Binding Proteins / metabolism*
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Enzyme Inhibitors / pharmacology
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HeLa Cells
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Humans
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Kinetics
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Nuclear Proteins
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Phosphorylation
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Protein Serine-Threonine Kinases / metabolism*
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Replication Protein A
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Simian virus 40 / drug effects
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Simian virus 40 / genetics*
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Simian virus 40 / radiation effects
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Wortmannin
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X-Rays
Substances
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Androstadienes
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Antigens, Polyomavirus Transforming
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DNA, Viral
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DNA-Binding Proteins
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Enzyme Inhibitors
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Nuclear Proteins
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RPA1 protein, human
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Replication Protein A
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DNA-Activated Protein Kinase
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PRKDC protein, human
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Protein Serine-Threonine Kinases
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Camptothecin
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Wortmannin