Human base excision repair complex is physically associated to DNA replication and cell cycle regulatory proteins.
It has been hypothesized that a replication associated repair pathway operates on base damage and single strand breaks (SSB) at replication forks. In this study, we present the isolation from the nuclei of human cycling cells of a multiprotein complex containing most of the essential components of base excision repair (BER)/SSBR, including APE1, UNG2, XRCC1 and POLbeta, DNA PK, replicative POLalpha, delta and epsilon, DNA ligase 1 and cell cycle regulatory protein cyclin A. Co-immunoprecipitation revealed that in this complex DNA repair proteins are physically associated to cyclin A and to DNA replication proteins including MCM7. This complex is endowed with DNA polymerase and protein kinase activity and is able to perform BER of uracil and AP sites. This finding suggests that a preassembled DNA repair machinery is constitutively active in cycling cells and is ready to be recruited at base damage and breaks occurring at replication forks.
Parlanti
Eleonora
E
Department of Environment and Primary Prevention, Section of Molecular Epidemiology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Locatelli
Giada
G
Maga
Giovanni
G
Dogliotti
Eugenia
E
D000818:Animals; D018797:Cell Cycle Proteins / Q000302:isolation & purification / Q000378:metabolism*; D019925:Cyclin A / Q000302:isolation & purification / Q000378:metabolism; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000302:isolation & purification / Q000378:metabolism*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000302:isolation & purification / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D051379:Mice; D064168:Minichromosome Maintenance Complex Component 7; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism
D018797:Cell Cycle Proteins; D019925:Cyclin A; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D004259:DNA-Directed DNA Polymerase; C101624:MCM7 protein, human; D064168:Minichromosome Maintenance Complex Component 7; D045643:DNA Repair Enzymes