scholarly journals Quantitative genomic analysis of RecA protein binding during DNA double-strand break repair reveals RecBCD action in vivo

2015 ◽  
Vol 112 (34) ◽  
pp. E4735-E4742 ◽  
Author(s):  
Charlotte A. Cockram ◽  
Milana Filatenkova ◽  
Vincent Danos ◽  
Meriem El Karoui ◽  
David R. F. Leach
Keyword(s):  
Protein Binding ◽  
Molecular Mechanisms ◽  
Reca Protein ◽  
Genomic Analysis ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Dna Double Strand Break ◽  
Break Repair

Understanding molecular mechanisms in the context of living cells requires the development of new methods of in vivo biochemical analysis to complement established in vitro biochemistry. A critically important molecular mechanism is genetic recombination, required for the beneficial reassortment of genetic information and for DNA double-strand break repair (DSBR). Central to recombination is the RecA (Rad51) protein that assembles into a spiral filament on DNA and mediates genetic exchange. Here we have developed a method that combines chromatin immunoprecipitation with next-generation sequencing (ChIP-Seq) and mathematical modeling to quantify RecA protein binding during the active repair of a single DSB in the chromosome ofEscherichia coli. We have used quantitative genomic analysis to infer the key in vivo molecular parameters governing RecA loading by the helicase/nuclease RecBCD at recombination hot-spots, known as Chi. Our genomic analysis has also revealed that DSBR at thelacZlocus causes a second RecBCD-mediated DSBR event to occur in the terminus region of the chromosome, over 1 Mb away.

The PARP inhibitor olaparib induces significant killing of ATM-deficient lymphoid tumor cells in vitro and in vivo

Blood ◽  
2010 ◽  
Vol 116 (22) ◽  
pp. 4578-4587 ◽  
Author(s):  
Victoria J. Weston ◽  
Ceri E. Oldreive ◽  
Anna Skowronska ◽  
David G. Oscier ◽  
Guy Pratt ◽  
...  
Keyword(s):  
Cell Line ◽  
Tumor Cells ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Prolymphocytic Leukemia ◽  
Dna Double Strand Break ◽  
Break Repair

Abstract The Ataxia Telangiectasia Mutated (ATM) gene is frequently inactivated in lymphoid malignancies such as chronic lymphocytic leukemia (CLL), T-prolymphocytic leukemia (T-PLL), and mantle cell lymphoma (MCL) and is associated with defective apoptosis in response to alkylating agents and purine analogues. ATM mutant cells exhibit impaired DNA double strand break repair. Poly (ADP-ribose) polymerase (PARP) inhibition that imposes the requirement for DNA double strand break repair should selectively sensitize ATM-deficient tumor cells to killing. We investigated in vitro sensitivity to the poly (ADP-ribose) polymerase inhibitor olaparib (AZD2281) of 5 ATM mutant lymphoblastoid cell lines (LCL), an ATM mutant MCL cell line, an ATM knockdown PGA CLL cell line, and 9 ATM-deficient primary CLLs induced to cycle and observed differential killing compared with ATM wildtype counterparts. Pharmacologic inhibition of ATM and ATM knockdown confirmed the effect was ATM-dependent and mediated through mitotic catastrophe independently of apoptosis. A nonobese diabetic/severe combined immunodeficient (NOD/SCID) murine xenograft model of an ATM mutant MCL cell line demonstrated significantly reduced tumor load and an increased survival of animals after olaparib treatment in vivo. Addition of olaparib sensitized ATM null tumor cells to DNA-damaging agents. We suggest that olaparib would be an appropriate agent for treating refractory ATM mutant lymphoid tumors.

scholarly journals Monitoring Homology Search during DNA Double-Strand Break Repair In Vivo

2013 ◽  
Vol 50 (2) ◽  
pp. 261-272 ◽  
Author(s):  
Jörg Renkawitz ◽  
Claudio A. Lademann ◽  
Marian Kalocsay ◽  
Stefan Jentsch
Keyword(s):  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Homology Search ◽  
Dna Double Strand Break ◽  
Break Repair

In vivo study of fidelity of DNA double-strand break repair in bacteriophage T4

2008 ◽  
Vol 44 (9) ◽  
pp. 1025-1030 ◽  
Author(s):  
V. P. Shcherbakov ◽  
S. T. Sizova ◽  
T. S. Shcherbakova ◽  
I. E. Granovsky ◽  
K. Yu. Popad’in
Keyword(s):  
Bacteriophage T4 ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
In Vivo Study ◽  
Dna Double Strand Break ◽  
Break Repair

scholarly journals A Glycine-Arginine Domain in Control of the Human MRE11 DNA Repair Protein

2008 ◽  
Vol 28 (9) ◽  
pp. 3058-3069 ◽  
Author(s):  
Ugo Déry ◽  
Yan Coulombe ◽  
Amélie Rodrigue ◽  
Andrzej Stasiak ◽  
Stéphane Richard ◽  
...  
Keyword(s):  
Genome Stability ◽  
Nuclease Activity ◽  
Strand Break ◽  
Arginine Methylation ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Focus Formation ◽  
Dna Double Strand Break ◽  
Break Repair

ABSTRACT Human MRE11 is a key enzyme in DNA double-strand break repair and genome stability. Human MRE11 bears a glycine-arginine-rich (GAR) motif that is conserved among multicellular eukaryotic species. We investigated how this motif influences MRE11 function. Human MRE11 alone or a complex of MRE11, RAD50, and NBS1 (MRN) was methylated in insect cells, suggesting that this modification is conserved during evolution. We demonstrate that PRMT1 interacts with MRE11 but not with the MRN complex, suggesting that MRE11 arginine methylation occurs prior to the binding of NBS1 and RAD50. Moreover, the first six methylated arginines are essential for the regulation of MRE11 DNA binding and nuclease activity. The inhibition of arginine methylation leads to a reduction in MRE11 and RAD51 focus formation on a unique double-strand break in vivo. Furthermore, the MRE11-methylated GAR domain is sufficient for its targeting to DNA damage foci and colocalization with γ-H2AX. These studies highlight an important role for the GAR domain in regulating MRE11 function at the biochemical and cellular levels during DNA double-strand break repair.

Molecular mechanisms of DNA double-strand break repair

1998 ◽  
Vol 8 (12) ◽  
pp. 483-489 ◽  
Author(s):  
Roland Kanaar ◽  
Jan H.J Hoeijmakers ◽  
Dik C van Gent
Keyword(s):  
Molecular Mechanisms ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Dna Double Strand Break ◽  
Break Repair

scholarly journals RNF4 is required for DNA double-strand break repair in vivo

2012 ◽  
Vol 20 (3) ◽  
pp. 490-502 ◽  
Author(s):  
R Vyas ◽  
R Kumar ◽  
F Clermont ◽  
A Helfricht ◽  
P Kalev ◽  
...  
Keyword(s):  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Dna Double Strand Break ◽  
Break Repair

scholarly journals Evidence for conservative (two-progeny) DNA double-strand break repair.

Genetics ◽  
1995 ◽  
Vol 139 (1) ◽  
pp. 5-17 ◽  
Author(s):  
T Yokochi ◽  
K Kusano ◽  
I Kobayashi
Keyword(s):  
Reca Protein ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Break Repair ◽  
Duplex Dna ◽  
Experimental Conditions ◽  
E Coli ◽  
Dna Double Strand Break ◽  
Break Repair ◽  
Set Up

Abstract The double-strand break repair models for homologous recombination propose that a double-strand break in a duplex DNA segment is repaired by gene conversion copying a homologous DNA segment. This is a type of conservative recombination, or two-progeny recombination, which generates two duplex DNA segments from two duplex DNA segments. Transformation with a plasmid carrying a double-strand gap and an intact homologous DNA segment resulted in products expected from such conservative (two-progeny) repair in Escherichia coli cells with active E. coli RecE pathway (recBC sbcA) or with active bacteriophage lambda Red pathway. Apparently conservative double-strand break repair, however, might result from successive events of nonconservative recombination, or one-progeny recombination, which generates only one recombinant duplex DNA segment from two segments, involving multiple plasmid molecules. Contribution of such intermolecular recombination was evaluated by transformation with a mixture of two isogenic parental plasmids marked with a restriction site polymorphism. Most of the gap repair products were from intramolecular and, therefore, conservative (two-progeny) reaction under the conditions chosen. Most were conservative even in the absence of RecA protein. The double-strand gap repair reaction was not affected by inversion of the unidirectional replication origin on the plasmid. These results demonstrate the presence of the conservative (two-progeny) double-strand break repair mechanism. These experiments do not rule out the occurrence of nonconservative (one-progeny) recombination since we set up experimental conditions that should favor detection of conservative (two-progeny) recombination.

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