scholarly journals Numerical and Spatial Patterning of Yeast Meiotic DNA Breaks by Tel1

2016 ◽  
Author(s):  
Neeman Mohibullah ◽  
Scott Keeney
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Damage ◽  
Deep Sequencing ◽  
Meiotic Recombination ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Spatial Patterning ◽  
Dna Breaks ◽  
Strand Breaks ◽  
Context Dependent

AbstractThe Spo11-generated double-strand breaks (DSBs) that initiate meiotic recombination are dangerous lesions that can disrupt genome integrity, so meiotic cells regulate their number, timing, and distribution. Here, we use Spo11-oligonucleotide complexes, a byproduct of DSB formation, to examine the contribution of the DNA damage-responsive kinase Tel1 (ortholog of mammalian ATM) to this regulation in Saccharomyces cerevisiae. A tel1Δ mutant had globally increased amounts of Spo11-oligonucleotide complexes and altered Spo11-oligonucleotide lengths, consistent with conserved roles for Tel1 in control of DSB number and processing. A kinase-dead tell mutation also increased Spo11-oligonucleotide levels, but mutating known Tel1 phosphotargets on Hop1 and Rec114 did not. Deep sequencing of Spo11 oligonucleotides from tel1Δ mutants demonstrated that Tel1 shapes the nonrandom DSB distribution in ways that are distinct but partially overlapping with previously described contributions of the recombination regulator Zip3. Finally, we uncover a context-dependent role for Tel1 in hotspot competition, in which an artificial DSB hotspot inhibits nearby hotspots. Evidence for Tel1-dependent competition involving strong natural hotspots is also provided.

scholarly journals Factors that affect the location and frequency of meiosis-induced double-strand breaks in Saccharomyces cerevisiae.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 55-66 ◽  
Author(s):  
T C Wu ◽  
M Lichten
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromatin Structure ◽  
Meiotic Recombination ◽  
Double Strand Breaks ◽  
Yeast Genome ◽  
Dna Breaks ◽  
Strand Breaks ◽  
Double Strand Dna Breaks ◽  
A Site ◽  
Chromosomal Sequences

Abstract Double-strand DNA breaks (DSBs) initiate meiotic recombination in Saccharomyces cerevisiae. DSBs occur at sites that are hypersensitive in nuclease digests of chromatin, suggesting a role for chromatin structure in determining DSB location. We show here that the frequency of DSBs at a site is not determined simply by DNA sequence or by features of chromatin structure. An arg4-containing plasmid was inserted at several different locations in the yeast genome. Meiosis-induced DSBs occurred at similar sites in pBR322-derived portions of the construct at all insert loci, and the frequency of these breaks varied in a manner that mirrored the frequency of meiotic recombination in the arg4 portion of the insert. However, DSBs did not occur in the insert-borne arg4 gene at a site that is frequently broken at the normal ARG4 locus, even though the insert-borne arg4 gene and the normal ARG4 locus displayed similar DNase I hypersensitivity patterns. Deletions that removed active DSB sites from an insert at HIS4 restored breaks to the insert-borne arg4 gene and to a DSB site in flanking chromosomal sequences. We conclude that the frequency of DSB at a site can be affected by sequences several thousand nucleotides away and suggest that this is because of competition between DSB sites for locally limited factors.

MEIOSIS CAN INDUCE RECOMBINATION IN rad52 MUTANTS OF SACCHAROMYCES CEREVISIAE

Genetics ◽  
1986 ◽  
Vol 113 (3) ◽  
pp. 531-550
Author(s):  
Michael A Resnick ◽  
John Nitiss ◽  
Charles Edwards ◽  
Robert E Malone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Selective Medium ◽  
Complete Loss ◽  
Double Strand Breaks ◽  
Rich Medium ◽  
Strand Breaks ◽  
Selective Media ◽  
Single Strand Breaks ◽  
Nutrient Rich Medium

ABSTRACT The RAD52 and RAD50 genes have previously been shown to be required for normal meiotic recombination and for various types of recombination occurring in mitotic cells. Recent evidence suggests that rad52 mutants might be defective in an intermediate recombination step; we therefore examined recombination during meiosis in several rad52 mutants at several different loci and in genetic backgrounds that yield efficient sporulation and synchronous meiosis. Similar to previous reports, spores from rad52 diploids are inviable and meiotic recombination is greatly reduced by rad52 mutations. However, intragenic recombinants were detected when cells were plated on selective media during meiosis; rad52 mutants experience induction of recombination between homologues under these special conditions. The frequencies of recombination at four loci were considerably greater than the mitotic controls; however, they were still at least 20 times lower than corresponding Rad+ strains. The prototrophs induced by meiosis in rad52 mutants were not typical meiotic recombinants because incubation in nutrient-rich medium before plating to selective medium resulted in the complete loss of recombinants. We propose that previously observed single-strand breaks that accumulate in rad52 mutants may be associated with recombinational intermediates that are resolved when cells are returned to selective mitotic media and that the meiosis-induced recombination in rad52 cells does not involve double-strand breaks.

scholarly journals Genome-Wide Redistribution of Meiotic Double-Strand Breaks in Saccharomyces cerevisiae

2006 ◽  
Vol 27 (5) ◽  
pp. 1868-1880 ◽  
Author(s):  
Nicolas Robine ◽  
Norio Uematsu ◽  
Franck Amiot ◽  
Xavier Gidrol ◽  
Emmanuel Barillot ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Binding Sites ◽  
Chromosomal Region ◽  
Double Strand Breaks ◽  
Dna Binding Domain ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Genome Wide ◽  
Local Stimulation

ABSTRACT Meiotic recombination is initiated by the formation of programmed DNA double-strand breaks (DSBs) catalyzed by the Spo11 protein. DSBs are not randomly distributed along chromosomes. To better understand factors that control the distribution of DSBs in budding yeast, we have examined the genome-wide binding and cleavage properties of the Gal4 DNA binding domain (Gal4BD)-Spo11 fusion protein. We found that Gal4BD-Spo11 cleaves only a subset of its binding sites, indicating that the association of Spo11 with chromatin is not sufficient for DSB formation. In centromere-associated regions, the centromere itself prevents DSB cleavage by tethered Gal4BD-Spo11 since its displacement restores targeted DSB formation. In addition, we observed that new DSBs introduced by Gal4BD-Spo11 inhibit surrounding DSB formation over long distances (up to 60 kb), keeping constant the number of DSBs per chromosomal region. Together, these results demonstrate that the targeting of Spo11 to new chromosomal locations leads to both local stimulation and genome-wide redistribution of recombination initiation and that some chromosomal regions are inherently cold regardless of the presence of Spo11.

scholarly journals Pathways and signatures of mutagenesis at targeted DNA nicks

2021 ◽  
Author(s):  
Nancy Maizels ◽  
Yinbo Zhang ◽  
Luther Davis
Keyword(s):  
Dna Damage ◽  
Deep Sequencing ◽  
Human Cells ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Potential Source ◽  
Frequent Form ◽  
Dna Nicks

Nicks are the most frequent form of DNA damage and a potential source of mutagenesis in human cells.   By deep sequencing, we have identified factors and pathways that promote and limit mutagenic repair at targeted nicks.   BRCA2 inhibits all categories of mutational events at nicks, including indels, SNVs and HDR.   DNA2 and RPA promote 5' resection.   Most insertions at nicks consist of a single C incorporated opposite the nick by the translesion polymerase REV1.   DNA2 and REV3 inhibit these 1 bp insertions; and DNA2 also inhibits 1 bp deletions.   Longer deletions are stimulated by DNA2, REV7 and POLQ.   Strikingly, POLQ generates most SNVs at both nicks and double-strand breaks.   These results identify mutagenic signatures of DNA2, REV1, REV3, REV7 and POLQ at nicks and highlight the potential for nicks to promote mutagenesis, especially in BRCA-deficient cells.

scholarly journals YGR042W/MTE1 Functions in Double-Strand Break Repair with MPH1

2015 ◽  
Author(s):  
Askar Yimit ◽  
TaeHyung Kim ◽  
Ranjith Anand ◽  
Sarah Meister ◽  
Jiongwen Ou ◽  
...  
Keyword(s):  
Dna Damage ◽  
Strand Break ◽  
Double Strand Break ◽  
Dna Helicase ◽  
Double Strand Breaks ◽  
Double Strand Break Repair ◽  
Dependent Manner ◽  
Dna Breaks ◽  
Strand Breaks ◽  
Break Repair

Double-strand DNA breaks occur upon exposure of cells to agents such as ionizing radiation and ultraviolet light or indirectly through replication fork collapse at DNA damage sites. If left unrepaired double-strand breaks can cause genome instability and cell death. In response to DNA damage, proteins involved in double-strand break repair by homologous recombination re-localize into discrete nuclear foci. We identified 29 proteins that co-localize with the recombination repair protein Rad52 in response to DNA damage. Of particular interest, Ygr042w/Mte1, a protein of unknown function, showed robust colocalization with Rad52. Mte1 foci fail to form when the DNA helicase Mph1 is absent. Mte1 and Mph1 form a complex, and are recruited to double-strand breaks in vivo in a mutually dependent manner. Mte1 is important for resolution of Rad52 foci during double-strand break repair, and for suppressing break-induced replication. Together our data indicate that Mte1 functions with Mph1 in double-strand break repair.

scholarly journals Telomere length dynamics in response to DNA damage in malaria parasites

2020 ◽  
Author(s):  
Jake Reed ◽  
Laura A Kirkman ◽  
Bjӧrn FC Kafsack ◽  
Christopher Mason ◽  
Kirk W Deitsch
Keyword(s):  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Breaks ◽  
Strand Breaks ◽  
Host Parasite Interactions ◽  
Evolutionarily Conserved ◽  
Long Read ◽  
Host Parasite ◽  
Variant Antigen ◽  
Subtelomeric Regions

SUMMARYMalaria remains a major cause of morbidity and mortality within the developing world. Recent work has implicated chromosome end stability and the repair of DNA breaks through telomere healing as potent drivers of variant antigen diversification, thus associating basic mechanisms for maintaining genome integrity with aspects of host-parasite interactions. Here we applied long-read sequencing technology to precisely examine the dynamics of telomere addition and chromosome end stabilization in response to double strand breaks within subtelomeric regions. We observed that the process of telomere healing induces the initial synthesis of telomere repeats well in excess of the minimal number required for end stability. However once stabilized, these newly created telomeres appear to function normally, eventually returning to a length nearing that of intact chromosome ends. These results parallel recent observations in humans, suggesting an evolutionarily conserved mechanism for chromosome end repair.

scholarly journals The meiotic recombination landscape ofDrosophila virilisis robust to mitotic damage during hybrid dysgenesis

2018 ◽  
Author(s):  
Lucas W. Hemmer ◽  
Guilherme Dias ◽  
Brittny Smith ◽  
Kelley Van Vaerenberghe ◽  
Ashley Howard ◽  
...  
Keyword(s):  
Dna Damage ◽  
Transposable Elements ◽  
Transposable Element ◽  
Meiotic Recombination ◽  
Genome Stability ◽  
Double Strand Breaks ◽  
Drosophila Virilis ◽  
Hybrid Dysgenesis ◽  
Male Recombination ◽  
Strand Breaks

ABSTRACTGermline DNA damage is a double-edged sword. Programmed double-strand breaks establish the foundation for meiotic recombination and chromosome segregation. However, double-strand breaks also pose a significant challenge for genome stability. Because of this, meiotic double-strand break formation is tightly regulated. However, natural selection can favor selfish behavior in the germline and transposable elements can cause double-strand breaks independent of the carefully regulated meiotic process. To understand how the regulatory mechanisms of meiotic recombination accommodate unregulated transposition, we have characterized the female recombination landscape in a syndrome of hybrid dysgenesis inDrosophila virilis. In this system, a cross between two strains ofD. viriliswith divergent transposable element and piRNA profiles results in germline transposition of diverse transposable elements, reduced fertility, and male recombination. We sought to determine how increased transposition during hybrid dysgenesis might perturb the meiotic recombination landscape. Our results show that the overall frequency and distribution of meiotic recombination is extremely robust to germline transposable element activation. However, we also find that hybrid dysgenesis can result in mitotic recombination within the female germline. Overall, these results show that landscape of meiotic recombination may be insensitive to the DNA damage caused by transposition during early development.

scholarly journals Hydrogen peroxide induces DNA single- and double-strand breaks in thyroid cells and is therefore a potential mutagen for this organ

2009 ◽  
Vol 16 (3) ◽  
pp. 845-856 ◽  
Author(s):  
Natacha Driessens ◽  
Soetkin Versteyhe ◽  
Chiraz Ghaddhab ◽  
Agnès Burniat ◽  
Xavier De Deken ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Damage ◽  
Cell Line ◽  
Double Strand Breaks ◽  
Human Thyroid ◽  
Alkaline Condition ◽  
Dna Breaks ◽  
Thyroid Cells ◽  
Strand Breaks ◽  
Rat Thyroid

DNA double-strand breaks (DSBs) are considered as one of the primary causes of cancer but their induction by hydrogen peroxide (H2O2) is still controversial. In this work, we studied whether the high levels of H2O2 produced in the thyroid to oxidize iodide could induce DNA modifications. Scores of DNA damage, in terms of strand breaks, were obtained by comet assay (alkaline condition for single-strand breaks (SSBs) and neutral condition for DSBs). We demonstrated that in a rat thyroid cell line (PCCl3), non-lethal concentrations of H2O2 (0.1–0.5 mmol/l) as well as irradiation (1–10 Gy) provoked a large number of SSBs (∼2–3 times control DNA damage values) but also high levels of DSBs (1.2–2.3 times control DNA damage values). We confirmed the generation of DSBs in this cell line and also in human thyroid in primary culture and in pig thyroid slices by measuring phosphorylation of histone H2AX. l-Buthionine-sulfoximine, an agent that depletes cells of glutathione, decreased the threshold to observe H2O2-induced DNA damage. Moreover, we showed that DNA breaks induced by H2O2 were more slowly repaired than those induced by irradiation. In conclusion, H2O2 causes SSBs and DSBs in thyroid cells. DSBs are produced in amounts comparable with those observed after irradiation but with a slower repair. These data support the hypothesis that the generation of H2O2 in thyroid could also play a role in mutagenesis particularly in the case of antioxidant defense deficiency.

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