Requirement for PCNA and RPA in interstrand crosslink-induced DNA synthesis.
Proliferating nuclear cell antigen (PCNA) and replication protein A (RPA) have proven to be essential elements in many aspects of DNA metabolism including replication, repair and recombination. We have developed an in vitro assay in which the presence of an interstrand crosslink stimulates the incorporation of radiolabeled nucleotides into both damaged and undamaged plasmid DNAs. Using this assay we have investigated the roles of PCNA and RPA in crosslink-induced DNA synthesis. p21, a potent inhibitor of PCNA, was found to strongly inhibit crosslink-induced incorporation. Addition of exogenous PCNA partially restored the resynthesis activity. Likewise, neutralization of RPA by monoclonal antibodies also inhibited incorporation, but the effect was somewhat more pronounced on the undamaged plasmid than the damaged plasmid. Addition of excess RPA also partially reversed antibody inhibition. These results indicate that both PCNA and RPA are required for efficient in vitro DNA resynthesis induced by interstrand crosslinks.
Li
L
L
Department of Experimental Radiation Oncology, University of Texas M.D.Anderson Cancer Center, Houston, TX 77030, USA.
Peterson
C A
CA
Zhang
X
X
Legerski
R J
RJ
D000911:Antibodies, Monoclonal / Q000276:immunology; D002457:Cell Extracts; D003432:Cross-Linking Reagents / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D005363:Ficusin / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D010957:Plasmids / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D051716:Replication Protein A
D000911:Antibodies, Monoclonal; C493956:CDKN1A protein, human; D002457:Cell Extracts; D003432:Cross-Linking Reagents; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; C497167:RPA1 protein, human; D051716:Replication Protein A; D004247:DNA; D005363:Ficusin