scholarly journals Ensuring meiotic DNA break formation in the mouse pseudoautosomal region

2019 ◽  
Author(s):  
Laurent Acquaviva ◽  
Michiel Boekhout ◽  
Mehmet E. Karasu ◽  
Kevin Brick ◽  
Florencia Pratto ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Sex Chromosome ◽  
Double Strand Breaks ◽  
Pseudoautosomal Region ◽  
Homologous Segment ◽  
Strand Breaks ◽  
Sister Chromatids ◽  
Cis And Trans ◽  
Order Structures ◽  
Break Formation

Sex chromosomes in males share only a diminutive homologous segment, the pseudoautosomal region (PAR), wherein meiotic double-strand breaks (DSBs), pairing, and crossing over must occur for correct segregation. How cells ensure PAR recombination is unknown. Here we delineate cis-and trans-acting factors that control PAR ultrastructure and make the PAR the hottest area of DSB formation in the male mouse genome. Prior to DSB formation, PAR chromosome axes elongate, sister chromatids separate, and DSB-promoting factors hyperaccumulate. These phenomena are linked to mo-2 minisatellite arrays and require ANKRD31 protein. We propose that the repetitive PAR sequence confers unique chromatin and higher order structures crucial for DSB formation, X–Y pairing, and recombination. Our findings establish a mechanistic paradigm of mammalian sex chromosome segregation during spermatogenesis.

scholarly journals Role for the Silencing Protein Dot1 in Meiotic Checkpoint Control

2000 ◽  
Vol 11 (10) ◽  
pp. 3601-3615 ◽  
Author(s):  
Pedro A. San-Segundo ◽  
G. Shirleen Roeder
Keyword(s):  
Chromosome Segregation ◽  
Double Strand Breaks ◽  
Meiotic Cell ◽  
Checkpoint Control ◽  
Strand Breaks ◽  
Meiotic Progression ◽  
Chromosome Synapsis ◽  
Sister Chromatids ◽  
Surveillance Mechanism ◽  
Dependent Pathway

During the meiotic cell cycle, a surveillance mechanism called the “pachytene checkpoint” ensures proper chromosome segregation by preventing meiotic progression when recombination and chromosome synapsis are defective. The silencing protein Dot1 (also known as Pch1) is required for checkpoint-mediated pachytene arrest of thezip1 and dmc1 mutants ofSaccharomyces cerevisiae. In the absence ofDOT1, the zip1 and dmc1mutants inappropriately progress through meiosis, generating inviable meiotic products. Other components of the pachytene checkpoint include the nucleolar protein Pch2 and the heterochromatin component Sir2. Indot1, disruption of the checkpoint correlates with the loss of concentration of Pch2 and Sir2 in the nucleolus. In addition to its checkpoint function, Dot1 blocks the repair of meiotic double-strand breaks by a Rad54-dependent pathway of recombination between sister chromatids. In vegetative cells, mutation ofDOT1 results in delocalization of Sir3 from telomeres, accounting for the impaired telomeric silencing in dot1.

scholarly journals RPA Mediates Recruitment of MRX to Forks and Double-Strand Breaks to Hold Sister Chromatids Together

2016 ◽  
Vol 64 (5) ◽  
pp. 951-966 ◽  
Author(s):  
Andrew Seeber ◽  
Anna Maria Hegnauer ◽  
Nicole Hustedt ◽  
Ishan Deshpande ◽  
Jérôme Poli ◽  
...  
Keyword(s):  
Double Strand Breaks ◽  
Strand Breaks ◽  
Sister Chromatids

scholarly journals Double-strand breaks are not the main cause of spontaneous sister chromatid exchange in wild-type yeast cells

2017 ◽  
Author(s):  
Clémence Claussin ◽  
David Porubský ◽  
Diana C.J. Spierings ◽  
Nancy Halsema ◽  
Stefan Rentas ◽  
...  
Keyword(s):  
Sister Chromatid ◽  
Sister Chromatid Exchange ◽  
Genome Instability ◽  
Single Cells ◽  
Double Strand Breaks ◽  
Yeast Cells ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Template Strand ◽  
Sister Chromatids

SummaryHomologous recombination involving sister chromatids is the most accurate, and thus most frequently used, form of recombination-mediated DNA repair. Despite its importance, sister chromatid recombination is not easily studied because it does not result in a change in DNA sequence, making recombination between sister chromatids difficult to detect. We have previously developed a novel DNA template strand sequencing technique, called Strand-seq, that can be used to map sister chromatid exchange (SCE) events genome-wide in single cells. An increase in the rate of SCE is an indicator of elevated recombination activity and of genome instability, which is a hallmark of cancer. In this study, we have adapted Strand-seq to detect SCE in the yeast Saccharomyces cerevisiae. Contrary to what is commonly thought, we find that most spontaneous SCE events are not due to the repair of DNA double-strand breaks.

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 Persistent DNA Repair Signaling and DNA Polymerase Theta Promote Broken Chromosome Segregation

2021 ◽  
Author(s):  
Delisa E Clay ◽  
Heidi S Bretscher ◽  
Erin Jezuit ◽  
Korie Bush ◽  
Donald T Fox
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Polymerase ◽  
Chromosome Segregation ◽  
Genome Instability ◽  
Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Alternative End Joining ◽  
Segregation Of Chromosomes

Cycling cells must respond to double-strand breaks (DSBs) to avoid genome instability. Mis-segregation of chromosomes with DSBs during mitosis results in micronuclei, aberrant structures linked to disease. How cells respond to DSBs during mitosis is incompletely understood. We previously showed that Drosophila papillar cells lack DSB checkpoints (as observed in many cancer cells). Here, we show that papillar cells still recruit early-acting repair machinery (Mre11 and RPA3) to DSBs. This machinery persists as foci on DSBs as cells enter mitosis. Repair foci are resolved in a step-wise manner during mitosis. Repair signaling kinetics at DSBs depends on both monoubiquitination of the Fanconi Anemia (FA) protein Fancd2 and the alternative end- joining protein DNA Polymerase Theta. Disruption of either or both of these factors causes micronuclei after DNA damage, which disrupts intestinal organogenesis. This study reveals a mechanism for how cells with inactive DSB checkpoints can respond to DNA damage that persists into mitosis.

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 Vilya, a component of the recombination nodule, is required for meiotic double-strand break formation in Drosophila

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Cathleen M Lake ◽  
Rachel J Nielsen ◽  
Fengli Guo ◽  
Jay R Unruh ◽  
Brian D Slaughter ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Strand Break ◽  
Double Strand Breaks ◽  
Crossing Over ◽  
Actual Process ◽  
Strand Breaks ◽  
Recombination Nodules ◽  
Immuno Electron Microscopy ◽  
Break Formation ◽  
Selection Of

Meiotic recombination begins with the induction of programmed double-strand breaks (DSBs). In most organisms only a fraction of DSBs become crossovers. Here we report a novel meiotic gene, vilya, which encodes a protein with homology to Zip3-like proteins shown to determine DSB fate in other organisms. Vilya is required for meiotic DSB formation, perhaps as a consequence of its interaction with the DSB accessory protein Mei-P22, and localizes to those DSB sites that will mature into crossovers. In early pachytene Vilya localizes along the central region of the synaptonemal complex and to discrete foci. The accumulation of Vilya at foci is dependent on DSB formation. Immuno-electron microscopy demonstrates that Vilya is a component of recombination nodules, which mark the sites of crossover formation. Thus Vilya links the mechanism of DSB formation to either the selection of those DSBs that will become crossovers or to the actual process of crossing over.

scholarly journals Activation of meiotic recombination by nuclear import of the DNA break hotspot-determining complex in fission yeast

2021 ◽  
Vol 134 (4) ◽  
pp. jcs253518 ◽  
Author(s):  
Mélody Wintrebert ◽  
Mai-Chi Nguyen ◽  
Gerald R. Smith
Keyword(s):  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
High Specificity ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Nuclear Entry ◽  
Strand Breaks ◽  
Protein Complex Formation ◽  
Complex Process ◽  
Localization Signal

ABSTRACTMeiotic recombination forms crossovers important for proper chromosome segregation and offspring viability. This complex process involves many proteins acting at each of the multiple steps of recombination. Recombination initiates by formation of DNA double-strand breaks (DSBs), which in the several species examined occur with high frequency at special sites (DSB hotspots). In Schizosaccharomyces pombe, DSB hotspots are bound with high specificity and strongly activated by linear element (LinE) proteins Rec25, Rec27 and Mug20, which form colocalized nuclear foci with Rec10, essential for all DSB formation and recombination. Here, we test the hypothesis that the nuclear localization signal (NLS) of Rec10 is crucial for coordinated nuclear entry after forming a complex with other LinE proteins. In NLS mutants, all LinE proteins were abundant in the cytoplasm, not the nucleus; DSB formation and recombination were much reduced but not eliminated. Nuclear entry of limited amounts of Rec10, apparently small enough for passive nuclear entry, can account for residual recombination. LinE proteins are related to synaptonemal complex proteins of other species, suggesting that they also share an NLS, not yet identified, and undergo protein complex formation before nuclear entry.This article has an associated First Person interview with Mélody Wintrebert, joint first author of the paper.

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