scholarly journals ATR/Mec1 prevents lethal meiotic recombination initiation on partially replicated chromosomes in budding yeast

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Hannah G Blitzblau ◽  
Andreas Hochwagen
Keyword(s):  
Chromosome Segregation ◽  
Budding Yeast ◽  
Meiotic Chromosome ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
Rapid Loss ◽  
Replication Checkpoint ◽  
Strand Breaks ◽  
Cdc7 Kinase

During gamete formation, crossover recombination must occur on replicated DNA to ensure proper chromosome segregation in the first meiotic division. We identified a Mec1/ATR- and Dbf4-dependent replication checkpoint in budding yeast that prevents the earliest stage of recombination, the programmed induction of DNA double-strand breaks (DSBs), when pre-meiotic DNA replication was delayed. The checkpoint acts through three complementary mechanisms: inhibition of Mer2 phosphorylation by Dbf4-dependent Cdc7 kinase, preclusion of chromosomal loading of Rec114 and Mre11, and lowered abundance of the Spo11 nuclease. Without this checkpoint, cells formed DSBs on partially replicated chromosomes. Importantly, such DSBs frequently failed to be repaired and impeded further DNA synthesis, leading to a rapid loss in cell viability. We conclude that a checkpoint-dependent constraint of DSB formation to duplicated DNA is critical not only for meiotic chromosome assortment, but also to protect genome integrity during gametogenesis.

The repair of endo/exogenous DNA double-strand breaks and its effects on meiotic chromosome segregation in oocytes

2019 ◽  
Vol 28 (20) ◽  
pp. 3422-3430 ◽  
Author(s):  
Jun-Yu Ma ◽  
Xie Feng ◽  
Xin-Yi Tian ◽  
Lei-Ning Chen ◽  
Xiao-Yan Fan ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Meiotic Chromosome ◽  
Genomic Structure ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Developmental Defects ◽  
Exogenous Dna ◽  
Strand Breaks ◽  
Dna Dsbs ◽  
Number Variation

Abstract Germ cell-derived genomic structure variants not only drive the evolution of species but also induce developmental defects in offspring. The genomic structure variants have different types, but most of them are originated from DNA double-strand breaks (DSBs). It is still not well known whether DNA DSBs exist in adult mammalian oocytes and how the growing and fully grown oocytes repair their DNA DSBs induced by endogenous or exogenous factors. In this study, we detected the endogenous DNA DSBs in the growing and fully grown mouse oocytes and found that the DNA DSBs mainly localized at the centromere-adjacent regions, which are also copy number variation hotspots. When the exogenous DNA DSBs were introduced by Etoposide, we found that Rad51-mediated homologous recombination (HR) was used to repair the broken DNA. However, the HR repair caused the chromatin intertwined and impaired the homologous chromosome segregation in oocytes. Although we had not detected the indication about HR repair of endogenous centromere-adjacent DNA DSBs, we found that Rad52 and RNA:DNA hybrids colocalized with these DNA DSBs, indicating that a Rad52-dependent DNA repair might exist in oocytes. In summary, our results not only demonstrated an association between endogenous DNA DSBs with genomic structure variants but also revealed one specific DNA DSB repair manner in oocytes.

scholarly journals Modulation of Prdm9-controlled meiotic chromosome asynapsis overrides hybrid sterility in mice

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Sona Gregorova ◽  
Vaclav Gergelits ◽  
Irena Chvatalova ◽  
Tanmoy Bhattacharyya ◽  
Barbora Valiskova ◽  
...  
Keyword(s):  
Meiotic Chromosome ◽  
Hybrid Sterility ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Recombination Hotspots ◽  
Chromosome Synapsis ◽  
Reproductive Isolation Mechanisms ◽  
Meiotic Recombination Hotspots ◽  
Isolation Mechanisms

Hybrid sterility is one of the reproductive isolation mechanisms leading to speciation. Prdm9, the only known vertebrate hybrid-sterility gene, causes failure of meiotic chromosome synapsis and infertility in male hybrids that are the offspring of two mouse subspecies. Within species, Prdm9 determines the sites of programmed DNA double-strand breaks (DSBs) and meiotic recombination hotspots. To investigate the relation between Prdm9-controlled meiotic arrest and asynapsis, we inserted random stretches of consubspecific homology on several autosomal pairs in sterile hybrids, and analyzed their ability to form synaptonemal complexes and to rescue male fertility. Twenty-seven or more megabases of consubspecific (belonging to the same subspecies) homology fully restored synapsis in a given autosomal pair, and we predicted that two or more DSBs within symmetric hotspots per chromosome are necessary for successful meiosis. We hypothesize that impaired recombination between evolutionarily diverged chromosomes could function as one of the mechanisms of hybrid sterility occurring in various sexually reproducing species.

scholarly journals Spatial chromosome folding and active transcription drive DNA fragility and formation of oncogenic MLL translocations

2018 ◽  
Author(s):  
Henrike Johanna Gothe ◽  
Britta Annika Maria Bouwman ◽  
Eduardo Gade Gusmao ◽  
Rossana Piccinno ◽  
Sergi Sayols ◽  
...  
Keyword(s):  
Hot Spots ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Transcriptional Elongation ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Physiological Relevance ◽  
Topoisomerase 2 ◽  
Active Transcription ◽  
Transcriptional Output

How spatial chromosome organization influences genome integrity is still poorly understood. Here we show that DNA double-strand breaks (DSBs) mediated by topoisomerase 2 (TOP2) activities, are enriched at chromatin loop anchors with high transcriptional activity. Recurrent DSBs occur at CTCF/cohesin bound sites at the bases of chromatin loops and their frequency positively correlates with transcriptional output and directionality. The physiological relevance of this preferential positioning is indicated by the finding that genes recurrently translocating to drive leukemias, are highly transcribed and are enriched at loop anchors. These genes accumulate DSBs at recurrent hot spots that give rise to chromosomal fusions relying on the activity of both TOP2 isoforms and on transcriptional elongation. We propose that transcription and 3D chromosome folding jointly pose a threat to genomic stability, and are key contributors to the occurrence of genome rearrangements that drive cancer.

scholarly journals Distinctive nuclear zone for RAD51-mediated homologous recombinational DNA repair

2021 ◽  
Author(s):  
Yasunori Horikoshi ◽  
Hiroki Shima ◽  
Wataru Kobayashi ◽  
Jiying Sun ◽  
Volker J Schmid ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Nuclear Architecture ◽  
Super Resolution ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Sister Chromatids ◽  
Super Resolution Microscopy ◽  
Damaged Dna

Genome-based functions are inseparable from the dynamic higher-order architecture of the cell nucleus. In this context, the repair of DNA damage is coordinated by precise spatiotemporal controls that target and regulate the repair machinery required to maintain genome integrity. However, the mechanisms that pair damaged DNA with intact template for repair by homologous recombination (HR) without illegitimate recombination remain unclear. This report highlights the intimate relationship between nuclear architecture and HR in mammalian cells. RAD51, the key recombinase of HR, forms spherical foci in S/G2 phases spontaneously. Using super-resolution microscopy, we show that following induction of DNA double-strand breaks RAD51 foci at damaged sites elongate to bridge between intact and damaged sister chromatids; this assembly occurs within bundle-shaped distinctive nuclear zones, requires interactions of RAD51 with various factors, and precedes ATP-dependent events involved the recombination of intact and damaged DNA. We observed a time-dependent transfer of single-stranded DNA overhangs, generated during HR, into such zones. Our observations suggest that RAD51-mediated homologous pairing during HR takes place within the distinctive nuclear zones to execute appropriate recombination.

scholarly journals Lessons from the meiotic recombination landscape of the ZMM deficient budding yeast Lachancea waltii

2021 ◽  
Author(s):  
Fabien Dutreux ◽  
Abhishek Dutta ◽  
Emilien Peltier ◽  
Sabrina Bibi-Triki ◽  
Anne Friedrich ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Budding Yeast ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Yeast Saccharomyces Cerevisiae ◽  
Strand Breaks ◽  
Crossover Interference ◽  
Recombination Hotspots ◽  
Elevated Frequency ◽  
Underlying Mechanisms

Meiotic recombination has been deeply characterized in a few model species only, notably in the budding yeast Saccharomyces cerevisiae. Interestingly, most members of the ZMM pathway that implements meiotic crossover interference in S. cerevisiae have been lost in Lachancea yeast species after the divergence of Lachancea kluyveri from the rest of the clade. This suggests major differences in the control of crossover distribution. After investigating meiosis in L. kluyveri, we determined the meiotic recombination landscape of Lachancea waltii and identified several characteristics that should help understand better the underlying mechanisms. Such characteristics include systematic regions of loss of heterozygosity (LOH) in L. waltii hybrids, compatible with dysregulated Spo11-mediated DNA double strand breaks (DSB) independently of meiosis. They include a higher recombination rate in L. waltii than in L. kluyveri despite the lack of multiple ZMM pro-crossover factors. L. waltii exhibits an elevated frequency of zero-crossover bivalents as L. kluyveri but opposite to S. cerevisiae. L. waltii gene conversion tracts lengths are comparable to those observed in S. cerevisiae and shorter than in L. kluyveri despite the lack of Mlh2, a factor limiting conversion tracts size in S. cerevisiae. L. waltii recombination hotspots are not shared with either S. cerevisiae or L. kluyveri, showing that meiotic recombination hotspots can evolve at a rather limited evolutionary scale within budding yeasts. Finally, in line with the loss of several ZMM genes, we found only residual crossover interference in L. waltii likely coming from the modest interference existing between recombination precursors.

scholarly journals Loop extrusion as a mechanism for DNA Double-Strand Breaks repair foci formation

2020 ◽  
Author(s):  
Coline Arnould ◽  
Vincent Rocher ◽  
Thomas Clouaire ◽  
Pierre Caron ◽  
Philippe. E. Mangeot ◽  
...  
Keyword(s):  
Chromatin Modification ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
Chromatin Domains ◽  
Chromosome Conformation ◽  
Strand Breaks ◽  
3D Genome ◽  
Damage Response ◽  
Transcription And Replication

DNA Double-Strand Breaks (DSBs) repair is essential to safeguard genome integrity. Upon DSBs, the ATM PI3K kinase rapidly triggers the establishment of megabase-sized, γH2AX-decorated chromatin domains which further act as seeds for the formation of DNA Damage Response (DDR) foci1. How these foci are rapidly assembled in order to establish a “repair-prone” environment within the nucleus is yet unclear. Topologically Associating Domains (TADs) are a key feature of 3D genome organization that regulate transcription and replication, but little is known about their contribution to DNA repair processes2,3. Here we found that TADs are functional units of the DDR, instrumental for the correct establishment of γH2AX/53BP1 chromatin domains in a manner that involves one-sided cohesin-mediated loop extrusion on both sides of the DSB. We propose a model whereby H2AX-containing nucleosomes are rapidly phosphorylated as they actively pass by DSB-anchored cohesin. Our work highlights the critical impact of chromosome conformation in the maintenance of genome integrity and provides the first example of a chromatin modification established by loop extrusion.

scholarly journals Control of meiotic double-strand-break formation by ATM: local and global views

2017 ◽  
Author(s):  
Agnieszka Lukaszewicz ◽  
Julian Lange ◽  
Scott Keeney ◽  
Maria Jasin
Keyword(s):  
Strand Break ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Future Research ◽  
Dna Double Strand Breaks ◽  
Time Loss ◽  
Strand Breaks ◽  
Research Perspectives ◽  
The Right ◽  
Break Formation

ABSTRACTDNA double-strand breaks (DSBs) generated by the SPO11 protein initiate meiotic recombination, an essential process for successful chromosome segregation during gametogenesis. The activity of SPO11 is controlled by multiple factors and regulatory mechanisms, such that the number of DSBs is limited and DSBs form at distinct positions in the genome and at the right time. Loss of this control can affect genome integrity or cause meiotic arrest by mechanisms that are not fully understood. Here we focus on the DSB-responsive kinase ATM and its functions in regulating meiotic DSB numbers and distribution. We review the recently discovered roles of ATM in this context, discuss their evolutionary conservation, and examine future research perspectives.

scholarly journals RSC Mobilizes Nucleosomes To Improve Accessibility of Repair Machinery to the Damaged Chromatin

2006 ◽  
Vol 27 (5) ◽  
pp. 1602-1613 ◽  
Author(s):  
Eun Yong Shim ◽  
Soo Jin Hong ◽  
Ji-Hyun Oum ◽  
Yvonne Yanez ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Dna Double Strand Breaks ◽  
Base Pairs ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Free Dna ◽  
Key Questions

ABSTRACT Repair of DNA double-strand breaks (DSBs) protects cells and organisms, as well as their genome integrity. Since DSB repair occurs in the context of chromatin, chromatin must be modified to prevent it from inhibiting DSB repair. Evidence supports the role of histone modifications and ATP-dependent chromatin remodeling in repair and signaling of chromosome DSBs. The key questions are, then, what the nature of chromatin altered by DSBs is and how remodeling of chromatin facilitates DSB repair. Here we report a chromatin alteration caused by a single HO endonuclease-generated DSB at the Saccharomyces cerevisiae MAT locus. The break induces rapid nucleosome migration to form histone-free DNA of a few hundred base pairs immediately adjacent to the break. The DSB-induced nucleosome repositioning appears independent of end processing, since it still occurs when the 5′-to-3′ degradation of the DNA end is markedly reduced. The tetracycline-controlled depletion of Sth1, the ATPase of RSC, or deletion of RSC2 severely reduces chromatin remodeling and loading of Mre11 and Yku proteins at the DSB. Depletion of Sth1 also reduces phosphorylation of H2A, processing, and joining of DSBs. We propose that RSC-mediated chromatin remodeling at the DSB prepares chromatin to allow repair machinery to access the break and is vital for efficient DSB repair.

scholarly journals Genome integrity and neurogenesis of postnatal hippocampal neural stem/progenitor cells require a unique regulator Filia

2020 ◽  
Vol 6 (44) ◽  
pp. eaba0682 ◽  
Author(s):  
Jingzheng Li ◽  
Yafang Shang ◽  
Lin Wang ◽  
Bo Zhao ◽  
Chunli Sun ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Neurodevelopmental Disorders ◽  
Double Strand Breaks ◽  
Genome Integrity ◽  
Replication Forks ◽  
Proof Of Concept ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Neural Stem Progenitor Cells

Endogenous DNA double-strand breaks (DSBs) formation and repair in neural stem/progenitor cells (NSPCs) play fundamental roles in neurogenesis and neurodevelopmental disorders. NSPCs exhibit heterogeneity in terms of lineage fates and neurogenesis activity. Whether NSPCs also have heterogeneous regulations on DSB formation and repair to accommodate region-specific neurogenesis has not been explored. Here, we identified a regional regulator Filia, which is predominantly expressed in mouse hippocampal NSPCs after birth and regulates DNA DSB formation and repair. On one hand, Filia protects stalling replication forks and prevents the replication stress-associated DNA DSB formation. On the other hand, Filia facilitates the homologous recombination–mediated DNA DSB repair. Consequently, Filia−/− mice had impaired hippocampal NSPC proliferation and neurogenesis and were deficient in learning, memory, and mood regulations. Thus, our study provided the first proof of concept demonstrating the region-specific regulations of DSB formation and repair in subtypes of NSPCs.

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