scholarly journals Rad18 and Rnf8 facilitate homologous recombination by two distinct mechanisms, promoting Rad51 focus formation and suppressing the toxic effect of nonhomologous end joining

Oncogene ◽  
2014 ◽  
Vol 34 (33) ◽  
pp. 4403-4411 ◽  
Author(s):  
S Kobayashi ◽  
Y Kasaishi ◽  
S Nakada ◽  
T Takagi ◽  
S Era ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Toxic Effect ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Focus Formation ◽  
Rad51 Focus

scholarly journals A New Saccharomyces cerevisiae Strain with a Mutant Smt3-Deconjugating Ulp1 Protein Is Affected in DNA Replication and Requires Srs2 and Homologous Recombination for Its Viability

2004 ◽  
Vol 24 (12) ◽  
pp. 5130-5143 ◽  
Author(s):  
Christine Soustelle ◽  
Laurence Vernis ◽  
Karine Fréon ◽  
Anne Reynaud-Angelin ◽  
Roland Chanet ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Recombination ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Recombination Mechanism ◽  
Growth Defects ◽  
Protein Conjugates ◽  
Synthetically Lethal ◽  
Mutant Cells ◽  
Insight Into

ABSTRACT The Saccharomyces cerevisiae Srs2 protein is involved in DNA repair and recombination. In order to gain better insight into the roles of Srs2, we performed a screen to identify mutations that are synthetically lethal with an srs2 deletion. One of them is a mutated allele of the ULP1 gene that encodes a protease specifically cleaving Smt3-protein conjugates. This allele, ulp1-I615N, is responsible for an accumulation of Smt3-conjugated proteins. The mutant is unable to grow at 37°C. At permissive temperatures, it still shows severe growth defects together with a strong hyperrecombination phenotype and is impaired in meiosis. Genetic interactions between ulp1 and mutations that affect different repair pathways indicated that the RAD51-dependent homologous recombination mechanism, but not excision resynthesis, translesion synthesis, or nonhomologous end-joining processes, is required for the viability of the mutant. Thus, both Srs2, believed to negatively control homologous recombination, and the process of recombination per se are essential for the viability of the ulp1 mutant. Upon replication, mutant cells accumulate single-stranded DNA interruptions. These structures are believed to generate different recombination intermediates. Some of them are fixed by recombination, and others require Srs2 to be reversed and fixed by an alternate pathway.

scholarly journals Ku Heterodimer-Independent End Joining in Trypanosoma brucei Cell Extracts Relies upon Sequence Microhomology

2007 ◽  
Vol 6 (10) ◽  
pp. 1773-1781 ◽  
Author(s):  
Peter Burton ◽  
David J. McBride ◽  
Jonathan M. Wilkes ◽  
J. David Barry ◽  
Richard McCulloch
Keyword(s):  
Homologous Recombination ◽  
Trypanosoma Brucei ◽  
Antigenic Variation ◽  
Bacterial Species ◽  
Nonhomologous End Joining ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Cell Extracts ◽  
Ligase Iv

ABSTRACT DNA double-strand breaks (DSBs) are repaired primarily by two distinct pathways: homologous recombination and nonhomologous end joining (NHEJ). NHEJ has been found in all eukaryotes examined to date and has been described recently for some bacterial species, illustrating its ancestry. Trypanosoma brucei is a divergent eukaryotic protist that evades host immunity by antigenic variation, a process in which homologous recombination plays a crucial function. While homologous recombination has been examined in some detail in T. brucei, little work has been done to examine what other DSB repair pathways the parasite utilizes. Here we show that T. brucei cell extracts support the end joining of linear DNA molecules. These reactions are independent of the Ku heterodimer, indicating that they are distinct from NHEJ, and are guided by sequence microhomology. We also demonstrate bioinformatically that T. brucei, in common with other kinetoplastids, does not encode recognizable homologues of DNA ligase IV or XRCC4, suggesting that NHEJ is either absent or mechanistically diverged in these pathogens.

scholarly journals Deletion of the DNA Ligase IV Gene in Candida glabrata Significantly Increases Gene-Targeting Efficiency

2015 ◽  
Vol 14 (8) ◽  
pp. 783-791 ◽  
Author(s):  
Yuke Cen ◽  
Alessandro Fiori ◽  
Patrick Van Dijck
Keyword(s):  
Homologous Recombination ◽  
Gene Targeting ◽  
Candida Glabrata ◽  
The United States ◽  
Genetic Alterations ◽  
Nonhomologous End Joining ◽  
Specific Gene ◽  
Phylogenetic Distance ◽  
End Joining ◽  
Content Type

ABSTRACTCandida glabratais reported as the second most prevalent human opportunistic fungal pathogen in the United States. Over the last decades, its incidence increased, whereas that ofCandida albicansdecreased slightly. One of the main reasons for this shift is attributed to the inherent tolerance ofC. glabratatoward the commonly used azole antifungal drugs. Despite a close phylogenetic distance toSaccharomyces cerevisiae, homologous recombination works with poor efficiency inC. glabratacompared to baker's yeast, in fact limiting targeted genetic alterations of the pathogen's genome. It has been shown that nonhomologous DNA end joining is dominant over specific gene targeting inC. glabrata. To improve the homologous recombination efficiency, we have generated a strain in which theLIG4gene has been deleted, which resulted in a significant increase in correct gene targeting. The very specific function of Lig4 in mediating nonhomologous end joining is the reason for the absence of clear side effects, some of which affect theku80mutant, another mutant with reduced nonhomologous end joining. We also generated aLIG4reintegration cassette. Our results show that thelig4mutant strain may be a valuable tool for theC. glabrataresearch community.

scholarly journals Inhibition of the ATR kinase enhances 5-FU sensitivity independently of nonhomologous end-joining and homologous recombination repair pathways

2020 ◽  
Vol 295 (37) ◽  
pp. 12946-12961
Author(s):  
Soichiro S. Ito ◽  
Yosuke Nakagawa ◽  
Masaya Matsubayashi ◽  
Yoshihiko M. Sakaguchi ◽  
Shinko Kobashigawa ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Mammalian Cells ◽  
Cell Cycle Checkpoint ◽  
Nonhomologous End Joining ◽  
Homologous Recombination Repair ◽  
Dna Breaks ◽  
End Joining ◽  
Nucleotide Synthesis ◽  
Recombination Repair ◽  
Repair Pathways

The anticancer agent 5-fluorouracil (5-FU) is cytotoxic and often used to treat various cancers. 5-FU is thought to inhibit the enzyme thymidylate synthase, which plays a role in nucleotide synthesis and has been found to induce single- and double-strand DNA breaks. ATR Ser/Thr kinase (ATR) is a principal kinase in the DNA damage response and is activated in response to UV– and chemotherapeutic drug–induced DNA replication stress, but its role in cellular responses to 5-FU is unclear. In this study, we examined the effect of ATR inhibition on 5-FU sensitivity of mammalian cells. Using immunoblotting, we found that 5-FU treatment dose-dependently induced the phosphorylation of ATR at the autophosphorylation site Thr-1989 and thereby activated its kinase. Administration of 5-FU with a specific ATR inhibitor remarkably decreased cell survival, compared with 5-FU treatment combined with other major DNA repair kinase inhibitors. Of note, the ATR inhibition enhanced induction of DNA double-strand breaks and apoptosis in 5-FU–treated cells. Using gene expression analysis, we found that 5-FU induced the activation of the intra-S cell-cycle checkpoint. Cells lacking BRCA2 were sensitive to 5-FU in the presence of ATR inhibitor. Moreover, ATR inhibition enhanced the efficacy of the 5-FU treatment, independently of the nonhomologous end-joining and homologous recombination repair pathways. These findings suggest that ATR could be a potential therapeutic target in 5-FU–based chemotherapy.

scholarly journals PARP3 affects the relative contribution of homologous recombination and nonhomologous end-joining pathways

2014 ◽  
Vol 42 (9) ◽  
pp. 5616-5632 ◽  
Author(s):  
Carole Beck ◽  
Christian Boehler ◽  
Josée Guirouilh Barbat ◽  
Marie-Elise Bonnet ◽  
Giuditta Illuzzi ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Relative Contribution

scholarly journals Gene Targeting in Aspergillus fumigatus by Homologous Recombination Is Facilitated in a Nonhomologous End- Joining-Deficient Genetic Background

2006 ◽  
Vol 5 (1) ◽  
pp. 212-215 ◽  
Author(s):  
Sven Krappmann ◽  
Christoph Sasse ◽  
Gerhard H. Braus
Keyword(s):  
Homologous Recombination ◽  
Aspergillus Fumigatus ◽  
Gene Targeting ◽  
Mutant Strain ◽  
Genetic Background ◽  
Opportunistic Pathogen ◽  
Nonhomologous End Joining ◽  
End Joining ◽  
Gene Encoding

ABSTRACT The akuA gene encoding the Ku70 component of the nonhomologous end-joining machinery was deleted in the opportunistic pathogen Aspergillus fumigatus. No obvious phenotype could be assessed for the corresponding mutant strain but relative frequencies of homologous recombination were increased as deduced from targeting the laccase-encoding abr2 gene.

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