The 3'-5' exonuclease of human DNA polymerase delta (pol delta) is regulated by pol delta accessory factors and deoxyribonucleoside triphosphates.
Human DNA polymerase delta (pol delta) is required for the synthesis of leading strand of simian virus 40 (SV40) DNA replication in vitro. Pol delta requires the accessory factors, proliferating cell nuclear antigen (PCNA), activator 1 (A1; also known as replication factor C [RF-C]), human single-stranded DNA binding protein (HSSB; also known as replication protein A [RP-A]) for the elongation of primed template DNA. Since pol delta has an associated 3'-5' exonuclease activity, the effect of pol delta accessory factors on the exonuclease activity was examined. The 3'-5' exonuclease activity was stimulated 8-10 fold by the addition of HSSB, and this stimulatory effect was preferential to HSSB since other SSBs from E. coli, T4 or adenovirus, had a little or no effect. The stimulatory effect of HSSB was markedly inhibited by the combined action of A1 and PCNA. Furthermore, the addition of deoxyribonucleoside triphosphates (dNTPs) completely abolished the effect of HSSB on the 3'-5' exonuclease activity even in the absence of pol delta accessory factors. These results suggest that accessory factors and dNTPs regulate both the polymerase and the 3'-5' exonuclease activities.
Lee
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Department of Virology and Molecular Biology, St Jude Children's Research Hospital, Memphis, TN 38101.
D002851:Chromatography, High Pressure Liquid; D004258:DNA Polymerase III; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003854:Deoxyribonucleotides / Q000378:metabolism*; D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D018398:Homeodomain Proteins; D006801:Humans; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D051716:Replication Protein A; D051818:Replication Protein C; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins
C096816:BCL2-related protein A1; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D003854:Deoxyribonucleotides; D018398:Homeodomain Proteins; C096063:MATA1 protein, S cerevisiae; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; C497167:RPA1 protein, human; D051716:Replication Protein A; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V; D051818:Replication Protein C