Roles of replication protein A and DNA-dependent protein kinase in the regulation of DNA replication following DNA damage.
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.
Department of Radiation Oncology, Kimmel Cancer Center of Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. ya.wang@mail.tju.edu
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Iliakis
D000730:Androstadienes / Q000494:pharmacology; D000952:Antigens, Polyomavirus Transforming / Q000378:metabolism; D002166:Camptothecin / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004249:DNA Damage; D004261:DNA Replication / Q000187:drug effects / Q000528:radiation effects; D004279:DNA, Viral / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D007700:Kinetics; D009687:Nuclear Proteins; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051716:Replication Protein A; D013539:Simian virus 40 / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D000077191:Wortmannin; D014965:X-Rays
D000730:Androstadienes; D000952:Antigens, Polyomavirus Transforming; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; C497167:RPA1 protein, human; D051716:Replication Protein A; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases; D002166:Camptothecin; D000077191:Wortmannin