Mammalian base excision repair by DNA polymerases delta and epsilon.
Oncogene
; 17(7): 835-43, 1998 Aug 20.
Article
em En
| MEDLINE
| ID: mdl-9780000
ABSTRACT
Two distinct pathways for completion of base excision repair (BER) have been discovered in eukaryotes the DNA polymerase beta (Pol beta)-dependent short-patch pathway that involves the replacement of a single nucleotide and the long-patch pathway that entails the resynthesis of 2-6 nucleotides and requires PCNA. We have used cell extracts from Pol beta-deleted mouse fibroblasts to separate subfractions containing either Pol delta or Pol epsilon. These fractions were then tested for their ability to perform both short- and long-patch BER in an in vitro repair assay, using a circular DNA template, containing a single abasic site at a defined position. Remarkably, both Pol delta and Pol epsilon were able to replace a single nucleotide at the lesion site, but the repair reaction is delayed compared to single nucleotide replacement by Pol beta. Furthermore, our observations indicated, that either Pol delta and/or Pol epsilon participate in the long-patch BER. PCNA and RF-C, but not RP-A are required for this process. Our data show for the first time that Pol delta and/or Pol epsilon are directly involved in the long-patch BER of abasic sites and might function as back-up system for Pol beta in one-gap filling reactions.
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Base de dados:
MEDLINE
Assunto principal:
Antígeno Nuclear de Célula em Proliferação
/
DNA Polimerase II
/
DNA Polimerase III
/
Reparo do DNA
Limite:
Animals
Idioma:
En
Ano de publicação:
1998
Tipo de documento:
Article