Second pathway for completion of human DNA base excision-repair: reconstitution with purified proteins and requirement for DNase IV (FEN1)

Klungland, Arne

doi:10.1093/emboj/16.11.3341

Cited by 715 publications

(587 citation statements)

References 60 publications

Supporting

Mentioning

557

Contrasting

Unclassified

Order By: Relevance

“…In contrast, a repair patch size of 2-8 deoxynucleotides was observed initially in reconstituted BER systems and subsequently in vivo, which was named long-patch BER (LP-BER). During in vitro repair of an AP site analog, lacking the aldehyde group, Polb could not remove the APE-generated 5′ blocking group via its dRP lyase activity [77][78][79][80]. Matsumoto's and Dogliotti's groups first showed that such a 5′ blocking group could be removed by the 5′-flap endonuclease 1 (FEN-1) normally required for removing the 5′ RNA primers from Okazaki fragments during DNA replication.…”

Section: Two Basic Modes Of Ber: Sn-vs Lp-bermentioning

confidence: 99%

Early steps in the DNA base excision/single-strand interruption repair pathway in mammalian cells

2008

View full text Add to dashboard Cite

Base excision repair (BER) is an evolutionarily conserved process for maintaining genomic integrity by eliminating several dozen damaged (oxidized or alkylated) or inappropriate bases that are generated endogenously or induced by genotoxicants, predominantly, reactive oxygen species (ROS). BER involves 4-5 steps starting with base excision by a DNA glycosylase, followed by a common pathway usually involving an AP-endonuclease (APE) to generate 3′ OH terminus at the damage site, followed by repair synthesis with a DNA polymerase and nick sealing by a DNA ligase. This pathway is also responsible for repairing DNA single-strand breaks with blocked termini directly generated by ROS. Nearly all glycosylases, far fewer than their substrate lesions particularly for oxidized bases, have broad and overlapping substrate range, and could serve as back-up enzymes in vivo. In contrast, mammalian cells encode only one APE, APE1, unlike two APEs in lower organisms. In spite of overall similarity, BER with distinct subpathways in the mammals is more complex than in E. coli. The glycosylases form complexes with downstream proteins to carry out efficient repair via distinct subpathways one of which, responsible for repair of strand breaks with 3′ phosphate termini generated by the NEIL family glycosylases or by ROS, requires the phosphatase activity of polynucleotide kinase instead of APE1. Different complexes may utilize distinct DNA polymerases and ligases. Mammalian glycosylases have nonconserved extensions at one of the termini, dispensable for enzymatic activity but needed for interaction with other BER and non-BER proteins for complex formation and organelle targeting. The mammalian enzymes are sometimes covalently modified which may affect activity and complex formation. The focus of this review is on the early steps in mammalian BER for oxidized damage.

show abstract

Section: Two Basic Modes Of Ber: Sn-vs Lp-bermentioning

confidence: 99%

Early steps in the DNA base excision/single-strand interruption repair pathway in mammalian cells

2008

View full text Add to dashboard Cite

show abstract

“…Since Rad27 cleaves 5' flaps in long patch BER [25] and has been implicated in NHEJ of ends with 5' flaps both in vivo and in vitro [20,21], we hypothesized that this nuclease might catalyze 5' dRP removal in the absence of the Pol4 lyase ( Figure 1B). We sought to test rejoining of 5' dRP-containing DSBs in pol4Δ rad27Δ double mutants, which would lack both the putative short and long patch NHEJ pathways.…”

Section: Yeast Can Rejoin 5' Drp-containing Dsbs In the Absence Of Bomentioning

confidence: 99%

Evidence that base stacking potential in annealed 3′ overhangs determines polymerase utilization in yeast nonhomologous end joining

Daley

Wilson

2008

DNA Repair

View full text Add to dashboard Cite

Nonhomologous end joining (NHEJ) directly rejoins DNA double-strand breaks (DSBs) when recombination is not possible. In Saccharomyces cerevisiae, the DNA polymerase Pol4 is required for gap filling when a short 3' overhang must prime DNA synthesis. Here, we examined further end variations to test specific hypotheses regarding Pol4 usage in NHEJ in vivo. Surprisingly, Pol4 dependence at 3' overhangs was reduced when a nonhomologous 5' flap nucleotide was present across from the gap, even though the mismatched nucleotide was resynthesized, not incorporated. In contrast, a gap with a 5' deoxyribosephosphate (dRP) was as Pol4-dependent as a gap with a 5' phosphate, demonstrating the importance of the downstream base in relaxing the Pol4 requirement. Combined with prior observations of Pol4-independent NHEJ of nicks with 5' hydroxyls, we suggest that base stacking interactions across the broken strands can stabilize a joint, allowing another polymerase to substitute for Pol4. This model predicts that a unique function of Pol4 is to actively stabilize template strands that lack stacking continuity. We also explored whether NHEJ end processing can occur via short and long patch pathways analogous to base excision repair. Results demonstrated that 5' dRPs could be removed in the absence of Pol4 lyase activity. The 5' flap endonuclease Rad27 was not required for repair in this or any situation tested, indicating that still other NHEJ 5' nucleases must exist.

show abstract

“…In these cases, the modified AP-site is repaired via the longpatch base excision repair (LP-BER) pathway in which pol-b, d or e incorporates 2-15 nucleotides displacing the strand containing the modified AP-site. The DNA flap structure is cleaved by Fen-1, and the nick is sealed by a DNA ligase (Bambara et al, 1997;Klungland and Lindahl 1997).…”

Section: Introductionmentioning

confidence: 99%

Cigarette smoke condensate-induced level of adenomatous polyposis coli blocks long-patch base excision repair in breast epithelial cells

et al. 2006

View full text Add to dashboard Cite

Our previous studies have shown that treatment with cigarette smoke condensate (CSC) transforms normal breast epithelial cell line, MCF-10A. In the present study, the mechanism of CSC-induced transformation of breast epithelial cells was examined. We first determined whether benzo[a]pyrene (B[a]P)-and CSC-induced levels of APC are capable of inhibiting long-patch base excision repair (LP-BER) since our earlier studies had shown that an interaction of APC with DNA polymerase b (pol-b) blocks strand-displacement synthesis. With the use of a novel in vivo LP-BER assay, it was demonstrated that increased and decreased APC levels in different breast cancer cell lines were associated with a decrease or increase in LP-BER activity, respectively. The effect of APC on LP-BER in malignant and pre-malignant breast epithelial cell lines was produced by either overexpression or knockdown of APC. Furthermore, it was shown that the decreased LP-BER in B[a]P-or CSC-treated premalignant breast epithelial cells is associated with an increased level of APC and decreased cell growth. Our results suggest that the decreased growth allows cells to repair the damaged DNA before mitosis, and failure to repair damaged DNA has the potential to transform premalignant breast epithelial cells.

show abstract

Second pathway for completion of human DNA base excision-repair: reconstitution with purified proteins and requirement for DNase IV (FEN1)

Cited by 715 publications

References 60 publications

Early steps in the DNA base excision/single-strand interruption repair pathway in mammalian cells

Early steps in the DNA base excision/single-strand interruption repair pathway in mammalian cells

Evidence that base stacking potential in annealed 3′ overhangs determines polymerase utilization in yeast nonhomologous end joining

Cigarette smoke condensate-induced level of adenomatous polyposis coli blocks long-patch base excision repair in breast epithelial cells

Contact Info

Product

Resources

About