FEN1 functions in long patch base excision repair under conditions of oxidative stress in vertebrate cells.
From in vitro studies, flap endonuclease 1 (FEN1) has been proposed to play a role in the long patch (LP) base excision repair (BER) subpathway. Yet the role of FEN1 in BER in the context of the living vertebrate cell has not been thoroughly explored. In the present study, we cloned a DT40 chicken cell line with a deletion in the FEN1 gene and found that these FEN1-deficient cells exhibited hypersensitivity to H(2)O(2). This oxidant produces genotoxic lesions that are repaired by BER, suggesting that the cells have a deficiency in BER affecting survival. In experiments with extracts from the isogenic FEN1 null and wild-type cell lines, the LP-BER activity of FEN1 null cells was deficient, whereas repair by the single-nucleotide BER subpathway was normal. Other consequences of the FEN1 deficiency were also evaluated. These results illustrate that FEN1 plays a role in LP-BER in higher eukaryotes, presumably by processing the flap-containing intermediates of BER.
Laboratory of Structural Biology, NIEHS, NIH, Research Triangle Park, North Carolina, USA.
Kenjiro
K
Asagoshi
Keizo
K
Tano
Paul D
PD
Chastain
Noritaka
N
Adachi
Eiichiro
E
Sonoda
Koji
K
Kikuchi
Hideki
H
Koyama
Kenji
K
Nagata
David G
DG
Kaufman
Shunichi
S
Takeda
Samuel H
SH
Wilson
Masami
M
Watanabe
James A
JA
Swenberg
Jun
J
Nakamura
D000818:Animals; D002460:Cell Line; D002645:Chickens; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D004260:DNA Repair / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics; D005057:Eukaryotic Cells / Q000378:metabolism; D045585:Flap Endonucleases / Q000235:genetics*; D006861:Hydrogen Peroxide / Q000633:toxicity; D009711:Nucleotides / Q000235:genetics; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics*; D014714:Vertebrates / Q000235:genetics / Q000378:metabolism
D009711:Nucleotides; D016877:Oxidants; D004247:DNA; D006861:Hydrogen Peroxide; D045585:Flap Endonucleases