DNA repair by nonhomologous end joining and homologous recombination during cell cycle in human cells

ABSTRACT A proper balance between the repair of DNA double-strand breaks (DSBs) by homologous recombination and nonhomologous end joining is critical for maintaining genome integrity and preventing tumorigenesis. This balance is regulated and fine-tuned by a variety of factors, including cell cycle and the chromatin environment. The histone acetyltransferase TIP60 was previously shown to suppress pathological end joining and promote homologous recombination. However, it is unknown how regulatory posttranslational modifications impact TIP60 acetyltransferase activity to influence the outcome of DSB responses. In this study, we report that phosphorylation of TIP60 on serines 90 and 86 is important for limiting the accumulation of the pro-end joining factor 53BP1 at DSBs in S and G2 cell cycle phases. Mutation of these sites disrupts histone acetylation changes in response to DNA damage, BRCA1 localization to DSBs, and poly(ADP-ribose) polymerase (PARP) inhibitor resistance. These findings reveal that phosphorylation directs TIP60-dependent acetylation to promote homologous recombination and maintain genome stability.

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Multiple Pathways Promote Short-Sequence Recombination in Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.22.15.5347-5356.2002 ◽

2002 ◽

Vol 22 (15) ◽

pp. 5347-5356 ◽

Cited By ~ 12

Author(s):

Glenn M. Manthey ◽

Adam M. Bailis

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Repair ◽

Homologous Recombination ◽

Mismatch Repair ◽

Nuclease Activity ◽

Nonhomologous End Joining ◽

Null Alleles ◽

Sequence Length ◽

Short Sequence ◽

End Joining

ABSTRACT In the budding yeast Saccharomyces cerevisiae, null alleles of several DNA repair and recombination genes confer defects in recombination that grow more severe with decreasing sequence length, indicating that they are required for short-sequence recombination (SSR). RAD1 and RAD10, which encode the subunits of the structure-specific endonuclease Rad1/10, are critical for SSR. MRE11, RAD50, and XRS2, which encode the subunits of M/R/X, another complex with nuclease activity, are also crucially important. Genetic evidence suggests that Rad1/10 and M/R/X act on the same class of substrates during SSR. MSH2 and MSH3, which encode subunits of Msh2/3, a complex active during mismatch repair and recombination, are also important for SSR but play a more restricted role. Additional evidence suggests that SSR is distinct from nonhomologous end joining and is superimposed upon basal homologous recombination.

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Nonhomologous end joining and homologous recombination DNA repair pathways in integration mutagenesis in the xylose-fermenting yeastPichia stipitis

FEMS Yeast Research ◽

10.1111/j.1567-1364.2008.00383.x ◽

2008 ◽

Vol 8 (5) ◽

pp. 735-743 ◽

Cited By ~ 30

Author(s):

Nicole Maassen ◽

Stefan Freese ◽

Barbara Schruff ◽

Volkmar Passoth ◽

Ulrich Klinner

Keyword(s):

Dna Repair ◽

Homologous Recombination ◽

Nonhomologous End Joining ◽

End Joining ◽

Repair Pathways

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Faculty Opinions recommendation of Preventing nonhomologous end joining suppresses DNA repair defects of Fanconi anemia.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.4015985.793492297 ◽

2014 ◽

Author(s):

Wade Clapp ◽

Grzegorz Nalepa

Keyword(s):

Dna Repair ◽

Fanconi Anemia ◽

Nonhomologous End Joining ◽

End Joining

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MiR223-3p promotes synthetic lethality in BRCA1-deficient cancers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1903150116 ◽

2019 ◽

Vol 116 (35) ◽

pp. 17438-17443 ◽

Cited By ~ 6

Author(s):

Gayathri Srinivasan ◽

Elizabeth A. Williamson ◽

Kimi Kong ◽

Aruna S. Jaiswal ◽

Guangcun Huang ◽

...

Keyword(s):

Dna Repair ◽

Cancer Cells ◽

Synthetic Lethality ◽

Negative Regulator ◽

Nonhomologous End Joining ◽

Chromosomal Translocations ◽

Replication Forks ◽

Repair Pathway ◽

End Joining ◽

Parp1 Inhibitors

Defects in DNA repair give rise to genomic instability, leading to neoplasia. Cancer cells defective in one DNA repair pathway can become reliant on remaining repair pathways for survival and proliferation. This attribute of cancer cells can be exploited therapeutically, by inhibiting the remaining repair pathway, a process termed synthetic lethality. This process underlies the mechanism of the Poly-ADP ribose polymerase-1 (PARP1) inhibitors in clinical use, which target BRCA1 deficient cancers, which is indispensable for homologous recombination (HR) DNA repair. HR is the major repair pathway for stressed replication forks, but when BRCA1 is deficient, stressed forks are repaired by back-up pathways such as alternative nonhomologous end-joining (aNHEJ). Unlike HR, aNHEJ is nonconservative, and can mediate chromosomal translocations. In this study we have found that miR223-3p decreases expression of PARP1, CtIP, and Pso4, each of which are aNHEJ components. In most cells, high levels of microRNA (miR) 223–3p repress aNHEJ, decreasing the risk of chromosomal translocations. Deletion of the miR223 locus in mice increases PARP1 levels in hematopoietic cells and enhances their risk of unprovoked chromosomal translocations. We also discovered that cancer cells deficient in BRCA1 or its obligate partner BRCA1-Associated Protein-1 (BAP1) routinely repress miR223-3p to permit repair of stressed replication forks via aNHEJ. Reconstituting the expression of miR223-3p in BRCA1- and BAP1-deficient cancer cells results in reduced repair of stressed replication forks and synthetic lethality. Thus, miR223-3p is a negative regulator of the aNHEJ DNA repair and represents a therapeutic pathway for BRCA1- or BAP1-deficient cancers.

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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

Molecular and Cellular Biology ◽

10.1128/mcb.24.12.5130-5143.2004 ◽

2004 ◽

Vol 24 (12) ◽

pp. 5130-5143 ◽

Cited By ~ 32

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.

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