scholarly journals Analysis of the Xenopus Werner syndrome protein in DNA double-strand break repair

2005 ◽  
Vol 171 (2) ◽  
pp. 217-227 ◽  
Author(s):  
Hong Yan ◽  
Jill McCane ◽  
Thomas Toczylowski ◽  
Chinyi Chen
Keyword(s):  
Werner Syndrome ◽  
Strand Break ◽  
Double Strand Break ◽  
Single Strand ◽  
Repair Pathway ◽  
Dsb Repair ◽  
Single Strand Annealing ◽  
Werner Syndrome Protein ◽  
Strand Annealing ◽  
Syndrome Protein

Werner syndrome is associated with premature aging and increased risk of cancer. Werner syndrome protein (WRN) is a RecQ-type DNA helicase, which seems to participate in DNA replication, double-strand break (DSB) repair, and telomere maintenance; however, its exact function remains elusive. Using Xenopus egg extracts as the model system, we found that Xenopus WRN (xWRN) is recruited to discrete foci upon induction of DSBs. Depletion of xWRN has no significant effect on nonhomologous end-joining of DSB ends, but it causes a significant reduction in the homology-dependent single-strand annealing DSB repair pathway. These results provide the first direct biochemical evidence that links WRN to a specific DSB repair pathway. The assay for single-strand annealing that was developed in this study also provides a powerful biochemical system for mechanistic analysis of homology-dependent DSB repair.

scholarly journals Replication protein A promotes 5′→3′ end processing during homology-dependent DNA double-strand break repair

2011 ◽  
Vol 192 (2) ◽  
pp. 251-261 ◽  
Author(s):  
Hong Yan ◽  
Thomas Toczylowski ◽  
Jill McCane ◽  
Chinyi Chen ◽  
Shuren Liao
Keyword(s):  
Werner Syndrome ◽  
Protein A ◽  
Replication Protein A ◽  
Strand Break ◽  
Double Strand Break ◽  
Single Strand ◽  
Replication Protein ◽  
Dsb Repair ◽  
Dna Double Strand Break ◽  
Single Strand Annealing

Replication protein A (RPA), the eukaryotic single-strand deoxyribonucleic acid (DNA [ss-DNA])–binding protein, is involved in DNA replication, nucleotide damage repair, mismatch repair, and DNA damage checkpoint response, but its function in DNA double-strand break (DSB) repair is poorly understood. We investigated the function of RPA in homology-dependent DSB repair using Xenopus laevis nucleoplasmic extracts as a model system. We found that RPA is required for single-strand annealing, one of the homology-dependent DSB repair pathways. Furthermore, RPA promotes the generation of 3′ single-strand tails (ss-tails) by stimulating both the Xenopus Werner syndrome protein (xWRN)–mediated unwinding of DNA ends and the subsequent Xenopus DNA2 (xDNA2)–mediated degradation of the 5′ ss-tail. Purified xWRN, xDNA2, and RPA are sufficient to carry out the 5′-strand resection of DNA that carries a 3′ ss-tail. These results provide strong biochemical evidence to link RPA to a specific DSB repair pathway and reveal a novel function of RPA in the generation of 3′ ss-DNA for homology-dependent DSB repair.

scholarly journals Rad51-Independent Interchromosomal Double-Strand Break Repair by Gene Conversion Requires Rad52 but Not Rad55, Rad57, or Dmc1

2007 ◽  
Vol 28 (3) ◽  
pp. 897-906 ◽  
Author(s):  
Thomas J. Pohl ◽  
Jac A. Nickoloff
Keyword(s):  
Gene Conversion ◽  
Strand Break ◽  
Double Strand Break ◽  
Single Strand ◽  
Homology Search ◽  
Wild Type ◽  
Dsb Repair ◽  
Single Strand Annealing ◽  
In The Wild ◽  
Break Induced Replication

ABSTRACT Homologous recombination (HR) is critical for DNA double-strand break (DSB) repair and genome stabilization. In yeast, HR is catalyzed by the Rad51 strand transferase and its “mediators,” including the Rad52 single-strand DNA-annealing protein, two Rad51 paralogs (Rad55 and Rad57), and Rad54. A Rad51 homolog, Dmc1, is important for meiotic HR. In wild-type cells, most DSB repair results in gene conversion, a conservative HR outcome. Because Rad51 plays a central role in the homology search and strand invasion steps, DSBs either are not repaired or are repaired by nonconservative single-strand annealing or break-induced replication mechanisms in rad51Δ mutants. Although DSB repair by gene conversion in the absence of Rad51 has been reported for ectopic HR events (e.g., inverted repeats or between plasmids), Rad51 has been thought to be essential for DSB repair by conservative interchromosomal (allelic) gene conversion. Here, we demonstrate that DSBs stimulate gene conversion between homologous chromosomes (allelic conversion) by >30-fold in a rad51Δ mutant. We show that Rad51-independent allelic conversion and break-induced replication occur independently of Rad55, Rad57, and Dmc1 but require Rad52. Unlike DSB-induced events, spontaneous allelic conversion was detected in both rad51Δ and rad52Δ mutants, but not in a rad51Δ rad52Δ double mutant. The frequencies of crossovers associated with DSB-induced gene conversion were similar in the wild type and the rad51Δ mutant, but discontinuous conversion tracts were fivefold more frequent and tract lengths were more widely distributed in the rad51Δ mutant, indicating that heteroduplex DNA has an altered structure, or is processed differently, in the absence of Rad51.

scholarly journals The deinococcal DdrB protein is involved in an early step of DNA double strand break repair and in plasmid transformation through its single-strand annealing activity

DNA Repair ◽  
2011 ◽  
Vol 10 (12) ◽  
pp. 1223-1231 ◽  
Author(s):  
Claire Bouthier de la Tour ◽  
Stéphanie Boisnard ◽  
Cédric Norais ◽  
Magali Toueille ◽  
Esma Bentchikou ◽  
...  
Keyword(s):  
Strand Break ◽  
Double Strand Break ◽  
Single Strand ◽  
Double Strand Break Repair ◽  
Early Step ◽  
Plasmid Transformation ◽  
Dna Double Strand Break ◽  
Single Strand Annealing ◽  
Break Repair ◽  
Strand Annealing

scholarly journals Analysis of BRCA1 Variants in Double-Strand Break Repair by Homologous Recombination and Single-Strand Annealing

2013 ◽  
Vol 34 (3) ◽  
pp. 439-445 ◽  
Author(s):  
William I. Towler ◽  
Jie Zhang ◽  
Derek J. R. Ransburgh ◽  
Amanda E. Toland ◽  
Chikashi Ishioka ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Strand Break ◽  
Double Strand Break ◽  
Single Strand ◽  
Double Strand Break Repair ◽  
Single Strand Annealing ◽  
Break Repair ◽  
Strand Annealing

scholarly journals Conservative Repair of a Chromosomal Double-Strand Break by Single-Strand DNA through Two Steps of Annealing

2006 ◽  
Vol 26 (20) ◽  
pp. 7645-7657 ◽  
Author(s):  
Francesca Storici ◽  
Joyce R. Snipe ◽  
Godwin K. Chan ◽  
Dmitry A. Gordenin ◽  
Michael A. Resnick
Keyword(s):  
Normal Cell ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Single Strand ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Single Strand Annealing ◽  
Repair Mechanisms ◽  
Strand Invasion ◽  
Strand Annealing

ABSTRACT The repair of chromosomal double-strand breaks (DSBs) is essential to normal cell growth, and homologous recombination is a universal process for DSB repair. We explored DSB repair mechanisms in the yeast Saccharomyces cerevisiae using single-strand oligonucleotides with homology to both sides of a DSB. Oligonucleotide-directed repair occurred exclusively via Rad52- and Rad59-mediated single-strand annealing (SSA). Even the SSA domain of human Rad52 provided partial complementation for a null rad52 mutation. The repair did not involve Rad51-driven strand invasion, and moreover the suppression of strand invasion increased repair with oligonucleotides. A DSB was shown to activate targeting by oligonucleotides homologous to only one side of the break at large distances (at least 20 kb) from the break in a strand-biased manner, suggesting extensive 5′ to 3′ resection, followed by the restoration of resected DNA to the double-strand state. We conclude that long resected chromosomal DSB ends are repaired by a single-strand DNA oligonucleotide through two rounds of annealing. The repair by single-strand DNA can be conservative and may allow for accurate restoration of chromosomal DNAs with closely spaced DSBs.

scholarly journals FKBP25 participates in DNA double-strand break repair

2020 ◽  
Vol 98 (1) ◽  
pp. 42-49 ◽  
Author(s):  
David Dilworth ◽  
Fade Gong ◽  
Kyle Miller ◽  
Christopher J. Nelson
Keyword(s):  
Homologous Recombination ◽  
Strand Break ◽  
Repair Pathway ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Peptide Bonds ◽  
Single Strand Annealing ◽  
Strand Annealing ◽  
Fk506 Binding Proteins

FK506-binding proteins (FKBPs) alter the conformation of proteins via cis–trans isomerization of prolyl-peptide bonds. While this activity can be demonstrated in vitro, the intractability of detecting prolyl isomerization events in cells has limited our understanding of the biological processes regulated by FKBPs. Here we report that FKBP25 is an active participant in the repair of DNA double-strand breaks (DSBs). FKBP25 influences DSB repair pathway choice by promoting homologous recombination (HR) and suppressing single-strand annealing (SSA). Consistent with this observation, cells depleted of FKBP25 form fewer Rad51 repair foci in response to etoposide and ionizing radiation, and they are reliant on the SSA repair factor Rad52 for viability. We find that FKBP25’s catalytic activity is required for promoting DNA repair, which is the first description of a biological function for this enzyme activity. Consistent with the importance of the FKBP catalytic site in HR, rapamycin treatment also impairs homologous recombination, and this effect is at least in part independent of mTor. Taken together these results identify FKBP25 as a component of the DNA DSB repair pathway.

scholarly journals FANCA Promotes DNA Double-Strand Break Repair by Catalyzing Single-Strand Annealing and Strand Exchange

2018 ◽  
Vol 71 (4) ◽  
pp. 621-628.e4 ◽  
Author(s):  
Anaid Benitez ◽  
Wenjun Liu ◽  
Anna Palovcak ◽  
Guanying Wang ◽  
Jaewon Moon ◽  
...  
Keyword(s):  
Strand Break ◽  
Double Strand Break ◽  
Single Strand ◽  
Strand Exchange ◽  
Double Strand Break Repair ◽  
Dna Double Strand Break ◽  
Single Strand Annealing ◽  
Break Repair ◽  
Strand Annealing
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