scholarly journals Physical basis for long-distance communication along meiotic chromosomes

2018 ◽  
Vol 115 (40) ◽  
pp. E9333-E9342 ◽  
Author(s):  
Kyle R. Fowler ◽  
Randy W. Hyppa ◽  
Gareth A. Cromie ◽  
Gerald R. Smith
Keyword(s):  
Fission Yeast ◽  
Strand Break ◽  
Physical Basis ◽  
Long Distance ◽  
Homologous Chromosomes ◽  
Crossover Interference ◽  
Meiotic Chromosomes ◽  
Dna Double Strand Break ◽  
Distance Communication ◽  
Multiple Levels

Viable gamete formation requires segregation of homologous chromosomes connected, in most species, by cross-overs. DNA double-strand break (DSB) formation and the resulting cross-overs are regulated at multiple levels to prevent overabundance along chromosomes. Meiotic cells coordinate these events between distant sites, but the physical basis of long-distance chromosomal communication has been unknown. We show that DSB hotspots up to ∼200 kb (∼35 cM) apart form clusters via hotspot-binding proteins Rec25 and Rec27 in fission yeast. Clustering coincides with hotspot competition and interference over similar distances. Without Tel1 (an ATM tumor-suppressor homolog), DSB and crossover interference become negative, reflecting coordinated action along a chromosome. These results indicate that DSB hotspots within a limited chromosomal region and bound by their protein determinants form a clustered structure that, via Tel1, allows only one DSB per region. Such a “roulette” process within clusters explains the observed pattern of crossover interference in fission yeast. Key structural and regulatory components of clusters are phylogenetically conserved, suggesting conservation of this vital regulation. Based on these observations, we propose a model and discuss variations in which clustering and competition between DSB sites leads to DSB interference and in turn produces crossover interference.

scholarly journals Mouse TEX15 is essential for DNA double-strand break repair and chromosomal synapsis during male meiosis

2008 ◽  
Vol 180 (4) ◽  
pp. 673-679 ◽  
Author(s):  
Fang Yang ◽  
Sigrid Eckardt ◽  
N. Adrian Leu ◽  
K. John McLaughlin ◽  
Peijing Jeremy Wang
Keyword(s):  
Meiotic Recombination ◽  
Strand Break ◽  
Male Meiosis ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Recombination Proteins ◽  
Meiotic Chromosomes ◽  
Dna Double Strand Break

During meiosis, homologous chromosomes undergo synapsis and recombination. We identify TEX15 as a novel protein that is required for chromosomal synapsis and meiotic recombination. Loss of TEX15 function in mice causes early meiotic arrest in males but not in females. Specifically, TEX15-deficient spermatocytes exhibit a failure in chromosomal synapsis. In mutant spermatocytes, DNA double-strand breaks (DSBs) are formed, but localization of the recombination proteins RAD51 and DMC1 to meiotic chromosomes is severely impaired. Based on these data, we propose that TEX15 regulates the loading of DNA repair proteins onto sites of DSBs and, thus, its absence causes a failure in meiotic recombination.

scholarly journals Linear elements are stable structures along the chromosome axis in fission yeast meiosis

Chromosoma ◽  
2021 ◽  
Author(s):  
Da-Qiao Ding ◽  
Atsushi Matsuda ◽  
Kasumi Okamasa ◽  
Yasushi Hiraoka
Keyword(s):  
Fission Yeast ◽  
Strand Break ◽  
Wide Field ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Meiotic Chromosomes ◽  
Linear Elements ◽  
Yeast Meiosis ◽  
Chromosome Axis ◽  
Stable Structures

AbstractThe structure of chromosomes dramatically changes upon entering meiosis to ensure the successful progression of meiosis-specific events. During this process, a multilayer proteinaceous structure called a synaptonemal complex (SC) is formed in many eukaryotes. However, in the fission yeast Schizosaccharomyces pombe, linear elements (LinEs), which are structures related to axial elements of the SC, form on the meiotic cohesin-based chromosome axis. The structure of LinEs has been observed using silver-stained electron micrographs or in immunofluorescence-stained spread nuclei. However, the fine structure of LinEs and their dynamics in intact living cells remain to be elucidated. In this study, we performed live cell imaging with wide-field fluorescence microscopy as well as 3D structured illumination microscopy (3D-SIM) of the core components of LinEs (Rec10, Rec25, Rec27, Mug20) and a linE-binding protein Hop1. We found that LinEs form along the chromosome axis and elongate during meiotic prophase. 3D-SIM microscopy revealed that Rec10 localized to meiotic chromosomes in the absence of other LinE proteins, but shaped into LinEs only in the presence of all three other components, the Rec25, Rec27, and Mug20. Elongation of LinEs was impaired in double-strand break-defective rec12− cells. The structure of LinEs persisted after treatment with 1,6-hexanediol and showed slow fluorescence recovery from photobleaching. These results indicate that LinEs are stable structures resembling axial elements of the SC.

scholarly journals ATR is a multifunctional regulator of male mouse meiosis

2017 ◽  
Author(s):  
Alexander Widger ◽  
Shantha K Mahadevaiah ◽  
Julian Lange ◽  
Elias Ellnati ◽  
Jasmin Zohren ◽  
...  
Keyword(s):  
Dna Damage ◽  
Male Mouse ◽  
Germ Line ◽  
Strand Break ◽  
Phosphatidylinositol 3 Kinase ◽  
Homologous Chromosomes ◽  
Dna Double Strand Break ◽  
Surveillance Mechanism ◽  
Chromosome Axis ◽  
Deficient Mice

Meiotic cells undergo genetic exchange between homologous chromosomes through programmed DNA double-strand break (DSB) formation, recombination and synapsis1, 2. In mice, the DNA damage-regulated phosphatidylinositol-3-kinase-like kinase (PIKK) ATM regulates all of these processes3-6. However, the meiotic functions of another major PIKK, ATR, have remained elusive, because germ line-specific depletion of this kinase is challenging. Using an efficient conditional strategy, we uncover roles for ATR in male mouse prophase I progression. Deletion of ATR causes chromosome axis fragmentation and germ cell elimination at mid pachynema. ATR is required for homologous synapsis, in a manner genetically dissociable from DSB formation. In addition, ATR regulates loading of recombinases RAD51 and DMC1 to DSBs and maintenance of recombination foci on synapsed and asynapsed chromosomes. Mid pachytene spermatocyte elimination in ATR deficient mice cannot be rescued by deletion of ATM and the third DNA damage-regulated PIKK, PRKDC, consistent with the existence of a PIKK-independent surveillance mechanism in the mammalian germ line. Our studies identify ATR as a multifunctional regulator of mouse meiosis.

scholarly journals Meiotic DNA Double-Strand Break Repair Requires Two Nucleases, MRN and Ctp1, To Produce a Single Size Class of Rec12 (Spo11)-Oligonucleotide Complexes

2009 ◽  
Vol 29 (22) ◽  
pp. 5998-6005 ◽  
Author(s):  
Neta Milman ◽  
Emily Higuchi ◽  
Gerald R. Smith
Keyword(s):  
Fission Yeast ◽  
Topoisomerase Ii ◽  
Budding Yeast ◽  
Strand Break ◽  
Size Class ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Short Oligonucleotide ◽  
Mrn Complex ◽  
Dna Double Strand Break

ABSTRACT Programmed DNA double-strand breaks (DSBs) in meiosis are formed by Spo11 (Rec12 in fission yeast), a topoisomerase II-like protein, which becomes covalently attached to DNA 5′ ends. For DSB repair through homologous recombination, the protein must be removed from these DNA ends. We show here that Rec12 is endonucleolytically removed from DSB ends attached to a short oligonucleotide (Rec12-oligonucleotide complex), as is Spo11 in budding yeast. Fission yeast, however, has only one size class of Rec12-oligonucleotide complexes, whereas budding yeast has two size classes, suggesting different endonucleolytic regulatory mechanisms. Rec12-oligonucleotide generation strictly requires Ctp1 (Sae2 nuclease homolog), the Rad32 (Mre11) nuclease domain, and Rad50 of the MRN complex. Surprisingly, Nbs1 is not strictly required, indicating separable roles for the MRN subunits. On the basis of these and other data, we propose that Rad32 nuclease has the catalytic site for Rec12-oligonucleotide generation and is activated by Ctp1, which plays an additional role in meiotic recombination.

scholarly journals ATM controls meiotic DNA double-strand break formation and recombination and affects synaptonemal complex organization in plants

2021 ◽  
Author(s):  
Marie-Therese Kurzbauer ◽  
Michael Peter Janisiw ◽  
Luis F Paulin ◽  
Ignacio Prusén Mota ◽  
Konstantin Tomanov ◽  
...  
Keyword(s):  
Synaptonemal Complex ◽  
Single Molecule ◽  
Super Resolution ◽  
Strand Break ◽  
Dna Double Strand Breaks ◽  
Meiotic Chromosomes ◽  
Genome Wide ◽  
Dna Double Strand Break ◽  
Meiotic Dsbs ◽  
Break Formation

Abstract Meiosis is a specialized cell division that gives rise to genetically distinct gametic cells. Meiosis relies on the tightly controlled formation of DNA double-strand breaks (DSBs) and their repair via homologous recombination for correct chromosome segregation. Like all forms of DNA damage, meiotic DSBs are potentially harmful and their formation activates an elaborate response to inhibit excessive DNA break formation and ensure successful repair. Previous studies established the protein kinase ATM as a DSB sensor and meiotic regulator in several organisms. Here we show that Arabidopsis ATM acts at multiple steps during DSB formation and processing, as well as crossover (CO) formation and synaptonemal complex (SC) organization, all vital for the successful completion of meiosis. We developed a single-molecule approach to quantify meiotic breaks and determined that ATM is essential to limit the number of meiotic DSBs. Local and genome-wide recombination screens showed that ATM restricts the number of interference-insensitive COs, while super-resolution STED nanoscopy of meiotic chromosomes revealed that the kinase affects chromatin loop size and SC length and width. Our study extends our understanding of how ATM functions during plant meiosis and establishes it as an integral factor of the meiotic program.

scholarly journals Let's get physical – mechanisms of crossover interference

2021 ◽  
Vol 134 (10) ◽  
Author(s):  
Lexy von Diezmann ◽  
Ofer Rog
Keyword(s):  
Molecular Mechanisms ◽  
Mechanistic Models ◽  
Signaling Proteins ◽  
Spatial Dynamic ◽  
Homologous Chromosomes ◽  
Crossover Interference ◽  
Physical Mechanisms ◽  
Meiotic Chromosomes ◽  
A Cell ◽  
Active Debate

ABSTRACT The formation of crossovers between homologous chromosomes is key to sexual reproduction. In most species, crossovers are spaced further apart than would be expected if they formed independently, a phenomenon termed crossover interference. Despite more than a century of study, the molecular mechanisms implementing crossover interference remain a subject of active debate. Recent findings of how signaling proteins control the formation of crossovers and about the interchromosomal interface in which crossovers form offer new insights into this process. In this Review, we present a cell biological and biophysical perspective on crossover interference, summarizing the evidence that links interference to the spatial, dynamic, mechanical and molecular properties of meiotic chromosomes. We synthesize this physical understanding in the context of prevailing mechanistic models that aim to explain how crossover interference is implemented.

scholarly journals A heterochromatin domain forms gradually at a new telomere and is highly dynamic at stable telomeres

2017 ◽  
Author(s):  
Jinyu Wang ◽  
Jessica R Eisenstatt ◽  
Julien Audry ◽  
Kristen Cornelius ◽  
Matthew Shaughnessy ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Histone H3 ◽  
Heterochromatic Region ◽  
Strand Break ◽  
Heterochromatin Formation ◽  
Dna Double Strand Break ◽  
Development And Aging ◽  
Organismal Development ◽  
Heterochromatin Domain

AbstractHeterochromatin domains play important roles in chromosome biology, organismal development and aging. In the fission yeast Schizosaccharomyces pombe and metazoans, heterochromatin is marked by histone H3 lysine 9 dimethylation. While factors required for heterochromatin have been identified, the dynamics of heterochromatin formation are poorly understood. Telomeres convert adjacent chromatin into heterochromatin. To form a new heterochromatic region in S. pombe, an inducible DNA double-strand break (DSB) was engineered next to 48 bp of telomere repeats in euchromatin, which caused formation of new telomere and gradual spreading of heterochromatin. However, spreading was highly dynamic even after the telomere had reached its stable length. The system also revealed the presence of repeats located at the boundaries of euchromatin and heterochromatin that are oriented to allow the efficient healing of a euchromatic DSB to cap the chromosome end with a new telomere. Telomere formation in S. pombe therefore reveals novel aspects of heterochromatin dynamics and the presence of failsafe mechanisms to repair subtelomeric breaks, with implications for similar processes in metazoan genomes.

scholarly journals RIF1 Links Replication Timing with Fork Reactivation and DNA Double-Strand Break Repair

2021 ◽  
Vol 22 (21) ◽  
pp. 11440
Author(s):  
Janusz Blasiak ◽  
Joanna Szczepańska ◽  
Anna Sobczuk ◽  
Michal Fila ◽  
Elzbieta Pawlowska
Keyword(s):  
Therapeutic Potential ◽  
3D Structure ◽  
Replication Timing ◽  
Strand Break ◽  
End Joining ◽  
Long Distance ◽  
Dna Double Strand Break ◽  
Microscopic Studies ◽  
Non Homologous End Joining ◽  
Cycle Regulation

Replication timing (RT) is a cellular program to coordinate initiation of DNA replication in all origins within the genome. RIF1 (replication timing regulatory factor 1) is a master regulator of RT in human cells. This role of RIF1 is associated with binding G4-quadruplexes and changes in 3D chromatin that may suppress origin activation over a long distance. Many effects of RIF1 in fork reactivation and DNA double-strand (DSB) repair (DSBR) are underlined by its interaction with TP53BP1 (tumor protein p53 binding protein). In G1, RIF1 acts antagonistically to BRCA1 (BRCA1 DNA repair associated), suppressing end resection and homologous recombination repair (HRR) and promoting non-homologous end joining (NHEJ), contributing to DSBR pathway choice. RIF1 is an important element of intra-S-checkpoints to recover damaged replication fork with the involvement of HRR. High-resolution microscopic studies show that RIF1 cooperates with TP53BP1 to preserve 3D structure and epigenetic markers of genomic loci disrupted by DSBs. Apart from TP53BP1, RIF1 interact with many other proteins, including proteins involved in DNA damage response, cell cycle regulation, and chromatin remodeling. As impaired RT, DSBR and fork reactivation are associated with genomic instability, a hallmark of malignant transformation, RIF1 has a diagnostic, prognostic, and therapeutic potential in cancer. Further studies may reveal other aspects of common regulation of RT, DSBR, and fork reactivation by RIF1.

scholarly journals DNA sequence differences are determinants of meiotic recombination outcome

2019 ◽  
Author(s):  
Simon D. Brown ◽  
Samantha J. Mpaulo ◽  
Mimi N. Asogwa ◽  
Marie Jézéquel ◽  
Matthew C. Whitby ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Relative Position ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Intragenic Recombination ◽  
Strong Impact ◽  
Dna Helicases ◽  
Homologous Chromosomes ◽  
Dna Double Strand Break ◽  
Sequence Polymorphisms

AbstractMeiotic recombination is essential for producing healthy gametes, and also generates genetic diversity. DNA double-strand break (DSB) formation is the initiating step of meiotic recombination, producing, among other outcomes, crossovers between homologous chromosomes (homologs), which provide physical links to guide accurate chromosome segregation. The parameters influencing DSB position and repair are thus crucial determinants of reproductive success and genetic diversity. Using Schizosaccharomyces pombe, we show that the distance between sequence polymorphisms across homologs has a strong impact on meiotic recombination rate. The closer the sequence polymorphisms are to each other across the homologs the fewer recombination events were observed. In the immediate vicinity of DSBs, sequence polymorphisms affect the frequency of intragenic recombination events (gene conversions). Additionally, and unexpectedly, the crossover rate of flanking markers tens of kilobases away from the sequence polymorphisms was affected by their relative position to each other amongst the progeny having undergone intragenic recombination. A major regulator of this distance-dependent effect is the MutSα-MutLα complex consisting of Msh2, Msh6, Mlh1, and Pms1. Additionally, the DNA helicases Rqh1 and Fml1 shape recombination frequency, although the effects seen here are largely independent of the relative position of the sequence polymorphisms.PreambleDue to a mistake during analysis of a batch of Sanger sequencing reactions for Supplementary Figure S1, we erroneously stated that we found evidence for intragenic crossovers. We now show that intragenic crossovers are less likely than we initially thought. We sincerely apologize for our mishap and any inconvenience it might have caused. However, this does not affect the main conclusions of our paper, just how some of our results are interpreted. This new manuscript version has been amended accordingly.

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