Mechanisms of DNA Recombination and Genome Rearrangements: Methods to Study Homologous Recombination

2018 ◽  
Keyword(s):  
Homologous Recombination ◽  
Dna Recombination ◽  
Genome Rearrangements

scholarly journals Mitochondrial Genome Rearrangements in Glomus Species Triggered by Homologous Recombination between Distinct mtDNA Haplotypes

2013 ◽  
Vol 5 (9) ◽  
pp. 1628-1643 ◽  
Author(s):  
Denis Beaudet ◽  
Yves Terrat ◽  
Sébastien Halary ◽  
Ivan Enrique de la Providencia ◽  
Mohamed Hijri
Keyword(s):  
Homologous Recombination ◽  
Mitochondrial Genome ◽  
Genome Rearrangements ◽  
Mtdna Haplotypes ◽  
Glomus Species

Dysregulated Apurinic/Apyrimidinic Endonucleases (Ape1 and Ape2) Lead to Genetic Instability in Multiple Myeloma.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1418-1418
Author(s):  
Masood A. Shammas ◽  
Hemant Koley ◽  
Sima Shah ◽  
Ramesh B. Batchu ◽  
Pierfrancesco Tassone ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Homologous Recombination ◽  
Genomic Instability ◽  
Cell Lines ◽  
Plasma Cells ◽  
Dna Recombination ◽  
Endonuclease Activity ◽  
Single Nucleotide ◽  
Genetic Changes

Abstract Multiple myeloma (MM) is associated with significant genomic instability. Homologous recombination (HR), which is elevated in MM, is considered to be responsible for this instability. As endonucleases play an important role in mediating HR, here we have evaluated the role of endonuclease in biology and progression of MM. Gene expression profile using Affymetrix U133 array showed > 2 fold elevation of Ape1 or Ape2 or both in 5 of 6 MM cell lines and 12 of 15 patient samples. Immunocytochemistry confirmed upregulation of Ape1 protein in MM cell lines. A Plasmid degradation assay confirmed significantly elevated endonuclease activity in MM cells compared to normal plasma cells. To identify the pre-dominating endonuclease activity, the degradation assay was carried out in the presence of specific endonuclease inhibitors. Harmane and methoxyamine (MA), specific inhibitors of apurinic/apyrimidinic endonucleases effectively inhibited significant endonuclease activity, while other endonuclease inhibitors ACPD and FK506 had minimal effects, confirming predominant role of apurinic/apyrimidinic endonucleases (APE) in mediating increased endonuclease activity in MM. We investigated the role of elevated APE endonuclease activity on DNA recombination and subsequent genomic re-arrangements. Using a plasmid-based assay we have previously demonstrated significantly elevated homologous recombination (HR) in MM. Inhibition of endonuclease by methoxyamine suppressed HR activity by 85 ± 2% in MM cells. Next, we evaluated whether inhibition of HR by methoxyamine can affect the frequency of acquisition of new genetic changes in MM cells using single nucleotide polymorphism (SNP) arrays (Affymetrix) as indicator of genomic instability. In three independent experiments, methoxyamine reduced the acquisition of new loss of heterozygocity (LOH) loci by an average of 71%. These data suggest that the dysregulated APE endonucleases contribute significantly to the genomic instability, acquisition of new mutations and progression of MM and provides the rationale for targeting endonuclease activity to prevent disease progression including development of drug resistance.

Intragenomic recombination in the highly leukotoxic JP2 clone of Actinobacillus actinomycetemcomitans

Microbiology ◽  
2005 ◽  
Vol 151 (10) ◽  
pp. 3371-3379 ◽  
Author(s):  
Kirsten T. Eriksen ◽  
Dorte Haubek ◽  
Knud Poulsen
Keyword(s):  
Homologous Recombination ◽  
Dna Fingerprinting ◽  
Restriction Enzyme ◽  
Multilocus Sequence Typing ◽  
African Descent ◽  
Rflp Analysis ◽  
Aggressive Periodontitis ◽  
Genome Rearrangements ◽  
Actinobacillus Actinomycetemcomitans

The highly leukotoxic JP2 clone of Actinobacillus actinomycetemcomitans is strongly associated with aggressive periodontitis in adolescents of African descent. DNA fingerprinting using the frequently cutting restriction enzyme MspI and multilocus sequence typing (MLST) showed that five strains of this clone were genetically virtually identical, although ribotyping of the six rrn genes and EcoRI RFLP analysis of the seven IS150-like elements revealed differences. PCR analyses demonstrated that these multi-copy sequences are subject to intragenomic homologous recombination, resulting in translocations or large inversions. The genome rearrangements were reflected in differences among 25 strains representing the JP2 clone in DNA fingerprinting using the rare-cutting restriction enzyme XhoI and resolved by PFGE. XhoI DNA fingerprinting provides a tool for studying local epidemiology, including transmission of this particularly pathogenic clone of A. actinomycetemcomitans.

scholarly journals Identification of MCM8IP, an interactor of MCM8-9 and RPA1 that promotes homologous recombination and DNA synthesis in response to DNA damage

2019 ◽  
Author(s):  
Jen-Wei Huang ◽  
Angelo Taglialatela ◽  
Ananya Acharya ◽  
Giuseppe Leuzzi ◽  
Tarun S. Nambiar ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Homologous Recombination ◽  
Dna Synthesis ◽  
Dna Recombination ◽  
Direct Interaction ◽  
Response To Treatment ◽  
Parp Inhibition ◽  
Dna Double Strand Breaks ◽  
Crosslinking Agents

ABSTRACTHomologous recombination (HR) mediates the error-free repair of DNA double-strand breaks to maintain genomic stability. HR is carried out by a complex network of DNA repair factors. Here we identify C17orf53/MCM8IP, an OB-fold containing protein that binds ssDNA, as a novel DNA repair factor involved in HR. MCM8IP-deficient cells exhibit HR defects, especially in long-tract gene conversion, occurring downstream of RAD51 loading, consistent with a role for MCM8IP in HR-dependent DNA synthesis. Moreover, loss of MCM8IP confers cellular sensitivity to crosslinking agents and PARP inhibition. Importantly, we identify a direct interaction with MCM8-9, a putative helicase complex mutated in Primary Ovarian Insufficiency, that is crucial for MCM8IP’s ability to promote resistance to DNA damaging agents. In addition to its association with MCM8-9, MCM8IP also binds directly to RPA1. We show that the interactions of MCM8IP with both MCM8-9 and RPA are required to maintain replication fork progression in response to treatment with crosslinking agents. Collectively, our work identifies MCM8IP as a key regulator of DNA damage-associated DNA synthesis during DNA recombination and replication.

scholarly journals An IncR Plasmid Harbored by a Hypervirulent Carbapenem-Resistant Klebsiella pneumoniae Strain Possesses Five Tandem Repeats of the blaKPC-2::NTEKPC-Id Fragment

2018 ◽  
Vol 63 (3) ◽  
Author(s):  
Ning Dong ◽  
Lizhang Liu ◽  
Rong Zhang ◽  
Kaichao Chen ◽  
Miaomiao Xie ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Klebsiella Pneumoniae ◽  
Tandem Repeats ◽  
Dna Recombination ◽  
Multidrug Resistant ◽  
Plasmid Evolution ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACT Completed sequences of three plasmids from a carbapenem-resistant hypervirulent Klebsiella pneumoniae isolate, SH9, were obtained. In addition to the pLVPK-like virulence-conferring plasmid (pVir-CR-HvKP_SH9), the two multidrug-resistant plasmids (pKPC-CR-HvKP4_SH9 and pCTX-M-CR-HvKP4_SH9) were predicted to originate from a single pKPC-CR-HvKP4-like multireplicon plasmid through homologous recombination. Interestingly, the blaKPC-2 gene was detectable in five tandem repeats exhibiting the format of an NTEKPC-Id-like transposon (IS26-ΔTn3-ISKpn8-blaKPC-2-ΔISKpn6-korC-orf-IS26). The data suggest an important role of DNA recombination in mediating active plasmid evolution.

scholarly journals Natural Competence Rates Are Variable Among Xylella fastidiosa Strains and Homologous Recombination Occurs In Vitro Between Subspecies fastidiosa and multiplex

2017 ◽  
Vol 30 (7) ◽  
pp. 589-600 ◽  
Author(s):  
Prem P. Kandel ◽  
Rodrigo P. P. Almeida ◽  
Paul A. Cobine ◽  
Leonardo De La Fuente
Keyword(s):  
Homologous Recombination ◽  
Fluorescent Protein ◽  
Xylella Fastidiosa ◽  
Dna Recombination ◽  
Bacterial Cells ◽  
Disease Emergence ◽  
Natural Competence ◽  
In Silico Studies ◽  
Green Fluorescent

Xylella fastidiosa, an etiological agent of emerging crop diseases around the world, is naturally competent for the uptake of DNA from the environment that is incorporated into its genome by homologous recombination. Homologous recombination between subspecies of X. fastidiosa was inferred by in silico studies and was hypothesized to cause disease emergence. However, no experimental data are available on the degree to which X. fastidiosa strains are capable of competence and whether recombination can be experimentally demonstrated between subspecies. Here, using X. fastidiosa strains from different subspecies, natural competence in 11 of 13 strains was confirmed with plasmids containing antibiotic markers flanked by homologous regions and, in three of five strains, with dead bacterial cells used as source of donor DNA. Recombination frequency differed among strains and was correlated to growth rate and twitching motility. Moreover, intersubspecific recombination occurred readily between strains of subsp. fastidiosa and multiplex, as demonstrated by movement of antibiotic resistance and green fluorescent protein from donor to recipient cells and confirmed by DNA sequencing of the flanking arms of recombinant strains. Results demonstrate that natural competence is widespread among X. fastidiosa strains and could have an impact in pathogen adaptation and disease development.

scholarly journals The Saccharomyces cerevisiae DNA Recombination and Repair Functions of the RAD52 Epistasis Group Inhibit Ty1 Transposition

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 543-556 ◽  
Author(s):  
Alison J Rattray ◽  
Brenda K Shafer ◽  
David J Garfinkel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Recombination ◽  
Dna Recombination ◽  
Recombinational Repair ◽  
Repair Pathway ◽  
Low Frequencies ◽  
Double Stranded Dna ◽  
High Level ◽  
In Cells

Abstract RNA transcribed from the Saccharomyces cerevisiae retrotransposon Ty1 accumulates to a high level in mitotically growing haploid cells, yet transposition occurs at very low frequencies. The product of reverse transcription is a linear double-stranded DNA molecule that reenters the genome by either Ty1-integrase-mediated insertion or homologous recombination with one of the preexisting genomic Ty1 (or δ) elements. Here we examine the role of the cellular homologous recombination functions on Ty1 transposition. We find that transposition is elevated in cells mutated for genes in the RAD52 recombinational repair pathway, such as RAD50, RAD51, RAD52, RAD54, or RAD57, or in the DNA ligase I gene CDC9, but is not elevated in cells mutated in the DNA repair functions encoded by the RAD1, RAD2, or MSH2 genes. The increase in Ty1 transposition observed when genes in the RAD52 recombinational pathway are mutated is not associated with a significant increase in Ty1 RNA or proteins. However, unincorporated Ty1 cDNA levels are markedly elevated. These results suggest that members of the RAD52 recombinational repair pathway inhibit Ty1 post-translationally by influencing the fate of Ty1 cDNA.

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