scholarly journals Control of meiotic pairing and recombination by chromosomally tethered 26S proteasome

Science ◽  
2017 ◽  
Vol 355 (6323) ◽  
pp. 408-411 ◽  
Author(s):  
Jasvinder S. Ahuja ◽  
Rima Sandhu ◽  
Rana Mainpal ◽  
Crystal Lawson ◽  
Hanna Henley ◽  
...  
Keyword(s):  
Synaptonemal Complex ◽  
Double Strand Breaks ◽  
26S Proteasome ◽  
Strand Exchange ◽  
Crossing Over ◽  
Meiotic Pairing ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Meiotic Chromosomes ◽  
Evolutionarily Conserved

During meiosis, paired homologous chromosomes (homologs) become linked via the synaptonemal complex (SC) and crossovers. Crossovers mediate homolog segregation and arise from self-inflicted double-strand breaks (DSBs). Here, we identified a role for the proteasome, the multisubunit protease that degrades proteins in the nucleus and cytoplasm, in homolog juxtaposition and crossing over. Without proteasome function, homologs failed to pair and instead remained associated with nonhomologous chromosomes. Although dispensable for noncrossover formation, a functional proteasome was required for a coordinated transition that entails SC assembly between longitudinally organized chromosome axes and stable strand exchange of crossover-designated DSBs. Notably, proteolytic core and regulatory proteasome particles were recruited to chromosomes by Zip3, the ortholog of mammalian E3 ligase RNF212, and SC protein Zip1 . We conclude that proteasome functions along meiotic chromosomes are evolutionarily conserved.

scholarly journals SPO16 binds SHOC1 to promote homologous recombination and crossing-over in meiotic prophase I

2019 ◽  
Vol 5 (1) ◽  
pp. eaau9780 ◽  
Author(s):  
Qianting Zhang ◽  
Shu-Yan Ji ◽  
Kiran Busayavalasa ◽  
Chao Yu
Keyword(s):  
Homologous Recombination ◽  
Meiotic Recombination ◽  
Double Strand Breaks ◽  
Crossing Over ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Recombination Nodules ◽  
Evolutionarily Conserved

Segregation of homologous chromosomes in meiosis I is tightly regulated by their physical links, or crossovers (COs), generated from DNA double-strand breaks (DSBs) through meiotic homologous recombination. In budding yeast, three ZMM (Zip1/2/3/4, Mer3, Msh4/5) proteins, Zip2, Zip4, and Spo16, form a “ZZS” complex, functioning to promote meiotic recombination via a DSB repair pathway. Here, we identified the mammalian ortholog of Spo16, termed SPO16, which interacts with the mammalian ortholog of Zip2 (SHOC1/MZIP2), and whose functions are evolutionarily conserved to promote the formation of COs. SPO16 localizes to the recombination nodules, as SHOC1 and TEX11 do. SPO16 is required for stabilization of SHOC1 and proper localization of other ZMM proteins. The DSBs formed in SPO16-deleted meiocytes were repaired without COs formation, although synapsis is less affected. Therefore, formation of SPO16-SHOC1 complex–associated recombination intermediates is a key step facilitating meiotic recombination that produces COs from yeast to mammals.

scholarly journals The Zip4 protein directly couples meiotic crossover formation to synaptonemal complex assembly

2021 ◽  
Author(s):  
Alexandra Pyatnitskaya ◽  
Jessica Andreani ◽  
Raphaël Guérois ◽  
Arnaud De Muyt ◽  
Valérie Borde
Keyword(s):  
Synaptonemal Complex ◽  
Central Element ◽  
Underlying Mechanism ◽  
Double Strand Breaks ◽  
General Mechanism ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Evolutionarily Conserved ◽  
Meiotic Crossover ◽  
Chromosome Axis

Meiotic recombination is triggered by programmed double-strand breaks (DSBs), a subset of these being repaired as crossovers, promoted by eight evolutionarily conserved proteins, named ZMM. Crossover formation is functionally linked to synaptonemal complex (SC) assembly between homologous chromosomes, but the underlying mechanism is unknown. Here we show that Ecm11, a SC central element protein, localizes on both DSB sites and sites that attach chromatin loops to the chromosome axis, which are the starting points of SC formation, in a way that strictly requires the ZMM protein Zip4. Furthermore, Zip4 directly interacts with Ecm11, and point mutants that specifically abolish this interaction lose Ecm11 binding to chromosomes and exhibit defective SC assembly. This can be partially rescued by artificially tethering interaction-defective Ecm11 to Zip4. Mechanistically, this direct connection ensuring SC assembly from CO sites could be a way for the meiotic cell to shut down further DSB formation once enough recombination sites have been selected for crossovers, thereby preventing excess crossovers. Finally, the mammalian ortholog of Zip4, TEX11, also interacts with the SC central element TEX12, suggesting a general mechanism.

scholarly journals The Zip4 protein directly couples meiotic crossover formation to synaptonemal complex assembly

2021 ◽  
Author(s):  
Alexandra Pyatnitskaya ◽  
Jessica Andreani ◽  
Raphael Guerois ◽  
Arnaud De Muyt ◽  
Valerie Borde
Keyword(s):  
Synaptonemal Complex ◽  
Central Element ◽  
Underlying Mechanism ◽  
Double Strand Breaks ◽  
General Mechanism ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Evolutionarily Conserved ◽  
Meiotic Crossover ◽  
Chromosome Axis

Meiotic recombination is triggered by programmed double-strand breaks (DSBs), a subset of these being repaired as crossovers, promoted by eight evolutionarily conserved proteins, named ZMM. Crossover formation is functionally linked to synaptonemal complex (SC) assembly between homologous chromosomes, but the underlying mechanism is unknown. Here we show that Ecm11, a SC central element protein, localizes on both DSB sites and sites that attach chromatin loops to the chromosome axis, which are the starting points of SC formation, in a way that strictly requires the ZMM protein Zip4. Furthermore, Zip4 directly interacts with Ecm11 and point mutants that specifically abolish this interaction lose Ecm11 binding to chromosomes and exhibit defective SC assembly. This can be partially rescued by artificially tethering interaction-defective Ecm11 to Zip4. Mechanistically, this direct connection ensuring SC assembly from CO sites could be a way for the meiotic cell to shut down further DSB formation once enough recombination sites have been selected for crossovers, thereby preventing excess crossovers. Finally, the mammalian ortholog of Zip4, TEX11, also interacts with the SC central element TEX12, suggesting a general mechanism.

scholarly journals The Yeast Motor Protein, Kar3p, Is Essential for Meiosis I

1997 ◽  
Vol 139 (2) ◽  
pp. 459-467 ◽  
Author(s):  
Carol A. Bascom-Slack ◽  
Dean S. Dawson
Keyword(s):  
Synaptonemal Complex ◽  
Meiotic Recombination ◽  
Molecular Motor ◽  
Motor Protein ◽  
Double Strand Breaks ◽  
Wild Type ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Low Levels ◽  
Meiosis I

The recognition and alignment of homologous chromosomes early in meiosis is essential for their subsequent segregation at anaphase I; however, the mechanism by which this occurs is unknown. We demonstrate here that, in the absence of the molecular motor, Kar3p, meiotic cells are blocked with prophase monopolar microtubule arrays and incomplete synaptonemal complex (SC) formation. kar3 mutants exhibit very low levels of heteroallelic recombination. kar3 mutants do produce double-strand breaks that act as initiation sites for meiotic recombination in yeast, but at levels severalfold reduced from wild-type. These data are consistent with a meiotic role for Kar3p in the events that culminate in synapsis of homologues.

scholarly journals Saccharomyces cerevisiae Mer3 Is a DNA Helicase Involved in Meiotic Crossing Over

2002 ◽  
Vol 22 (10) ◽  
pp. 3281-3291 ◽  
Author(s):  
Takuro Nakagawa ◽  
Richard D. Kolodner
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Helicase ◽  
Double Strand Breaks ◽  
Crossing Over ◽  
Helicase Activity ◽  
Wild Type ◽  
Rna Helicases ◽  
Conserved Residues ◽  
Strand Breaks ◽  
Homologous Chromosomes

ABSTRACT Crossing over is regulated to occur at least once per each pair of homologous chromosomes during meiotic prophase to ensure proper segregation of chromosomes at the first meiotic division. In a mer3 deletion mutant of Saccharomyces cerevisiae, crossing over is decreased, and the distribution of the crossovers that occur is random. The predicted Mer3 protein contains seven motifs characteristic of the DExH box type of DNA/RNA helicases. The mer3G166D and the mer3K167A mutation, amino acid substitutions of conserved residues in a putative nucleotide-binding domain of the helicase motifs caused a defect in the transition of meiosis-specific double-strand breaks to later intermediates, decreased crossing over, and reduced crossover interference. The purified Mer3 protein was found to have DNA helicase activity. This helicase activity was reduced by the mer3GD mutation to <1% of the wild-type activity, even though binding of the mutant protein to single- and double-strand DNA was unaffected. The mer3KA mutation eliminated the ATPase activity of the wild-type protein. These results demonstrate that Mer3 is a DNA helicase that functions in meiotic crossing over.

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 Coupling crossover and synaptonemal complex in meiosis

2022 ◽  
Vol 36 (1-2) ◽  
pp. 4-6
Author(s):  
Corinne Grey ◽  
Bernard de Massy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Homologous Recombination ◽  
Synaptonemal Complex ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Strand Breaks ◽  
Homologous Chromosomes

During meiosis, a molecular program induces DNA double-strand breaks (DSBs) and their repair by homologous recombination. DSBs can be repaired with or without crossovers. ZMM proteins promote the repair toward crossover. The sites of DSB repair are also sites where the axes of homologous chromosomes are juxtaposed and stabilized, and where a structure called the synaptonemal complex initiates, providing further regulation of both DSB formation and repair. How crossover formation and synapsis initiation are linked has remained unknown. The study by Pyatnitskaya and colleagues (pp. 53–69) in this issue of Genes & Development highlights the central role of the Saccharomyces cerevisiae ZMM protein Zip4 in this process.

scholarly journals The BRCA1-BARD1 complex associates with the synaptonemal complex and pro-crossover factors and influences RAD-51 dynamics during Caenorhabditis elegans meiosis

2018 ◽  
Author(s):  
Eva Janisiw ◽  
Maria Rosaria Dello Stritto ◽  
Verena Jantsch ◽  
Nicola Silva
Keyword(s):  
Dna Repair ◽  
Caenorhabditis Elegans ◽  
Synaptonemal Complex ◽  
Meiotic Prophase ◽  
Double Strand Breaks ◽  
Pivotal Role ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Meiotic Prophase I

AbstractDuring meiosis, the maternal and paternal homologous chromosomes must align along their entire length and recombine to achieve faithful segregation in the gametes. Meiotic recombination is accomplished through the formation of DNA double-strand breaks, a subset of which can mature into crossovers to link the parental homologous chromosomes and promote their segregation. Breast and ovarian cancer susceptibility protein BRCA1 and its heterodimeric partner BARD1 play a pivotal role in DNA repair in mitotic cells; however, their functions in gametogenesis are less well understood. Here we show that localization of BRC-1 and BRD-1 (Caenorhabditis elegans orthologues of BRCA1 and BARD1) is dynamic during meiotic prophase I; they ultimately becoming concentrated at regions surrounding the presumptive crossover sites, co-localizing with the pro-crossover factors COSA-1, MSH-5 and ZHP-3. The synaptonemal complex is essential for BRC-1 loading onto chromosomes but recombination is not. BRC-1 forms an in vivo complex with the synaptonemal complex component SYP-3 and the crossover-promoting factor MSH-5. Furthermore, BRC-1 is essential for efficient stage-specific recruitment of the RAD-51 recombinase to DNA damage sites when synapsis is impaired and upon induction of exogenous DNA double-strand breaks. Taken together, our data provide new insights into the localization and meiotic function of the BRC-1–BRD-1 complex and highlight their essential role in DNA double-strand break repair during gametogenesis.Author summarySexually reproducing species rely on meiosis to transmit their genetic information across generations. Parental chromosomes (homologues) undergo many distinctive processes in their complex journey from attachment to segregation. The physiological induction of DNA double strand breaks is crucial for promoting correct chromosome segregation: they are needed to activate the DNA repair machinery responsible for creating physical connections, or crossovers (COs), between the homologues. In turn, crossovers promote the accurate segregation of the chromosomes in daughter cells. The BRCA1–BARD1 complex has a pivotal role during DNA repair in somatic cells and is exclusively located on unaligned chromosomal regions during mammalian meiosis. We show that in Caenorhabditis elegans, BRCA1 and BARD1 localize to chromosomes at all stages of meiotic prophase I and are enriched at presumptive crossover sites. We found that BRCA1 promotes DNA loading of the repair factor RAD-51 in specific mutant backgrounds and upon exogenous damage induction. Our data provide evidence for a direct physical association between BRCA1 and pro-crossover factors (including the synaptonemal complex) and identify an important role for BRCA1 in stimulating meiotic DNA repair. Further studies are necessary to identify the substrates acted upon by BRCA1–BARD1 complex to maintain genome stability in the gametes.

scholarly journals Chromosome-autonomous feedback downregulates meiotic DSB competence upon synaptonemal complex formation

2020 ◽  
Author(s):  
Xiaojing Mu ◽  
Hajime Murakami ◽  
Neeman Mohibullah ◽  
Scott Keeney
Keyword(s):  
Synaptonemal Complex ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Homologous Chromosomes ◽  
Protein Dissociation ◽  
Homeologous Chromosome ◽  
Prolonged Retention ◽  
Synaptonemal Complex Formation ◽  
Insight Into

The number of DNA double-strand breaks (DSBs) initiating meiotic recombination is elevated in Saccharomyces cerevisiae mutants that are globally defective in forming crossovers and synaptonemal complex (SC), a protein scaffold juxtaposing homologous chromosomes. These mutants thus appear to lack a negative feedback loop that inhibits DSB formation when homologs engage one another. This feedback is predicted to be chromosome autonomous, but this has not been tested. Moreover, what chromosomal process is recognized as "homolog engagement" remains unclear. To address these questions, we evaluated effects of homolog engagement defects restricted to small portions of the genome using karyotypically abnormal yeast strains with a homeologous chromosome V pair, monosomic V, or trisomy XV. We found that homolog-engagement-defective chromosomes incurred more DSBs, concomitant with prolonged retention of the DSB-promoting protein Rec114, while the rest of the genome remained unaffected. SC-deficient, crossover-proficient mutants ecm11 and gmc2 experienced increased DSB numbers diagnostic of homolog engagement defects. These findings support the hypothesis that SC formation provokes DSB protein dissociation, leading in turn to loss of a DSB competent state. Our findings show that DSB number is regulated in a chromosome-autonomous fashion and provide insight into how homeostatic DSB controls respond to aneuploidy during meiosis.

scholarly journals MEIOK21: a new component of meiotic recombination bridges required for spermatogenesis

2020 ◽  
Vol 48 (12) ◽  
pp. 6624-6639
Author(s):  
Yongliang Shang ◽  
Tao Huang ◽  
Hongbin Liu ◽  
Yanlei Liu ◽  
Heng Liang ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Double Strand Breaks ◽  
Strand Exchange ◽  
Homology Search ◽  
Physical Interaction ◽  
Dna Double Strand Breaks ◽  
Dsb Repair ◽  
Chromosome Localization ◽  
Strand Breaks ◽  
Homologous Chromosomes

Abstract Repair of DNA double-strand breaks (DSBs) with homologous chromosomes is a hallmark of meiosis that is mediated by recombination ‘bridges’ between homolog axes. This process requires cooperation of DMC1 and RAD51 to promote homology search and strand exchange. The mechanism(s) regulating DMC1/RAD51-ssDNA nucleoprotein filament and the components of ‘bridges’ remain to be investigated. Here we show that MEIOK21 is a newly identified component of meiotic recombination bridges and is required for efficient formation of DMC1/RAD51 foci. MEIOK21 dynamically localizes on chromosomes from on-axis foci to ‘hanging foci’, then to ‘bridges’, and finally to ‘fused foci’ between homolog axes. Its chromosome localization depends on DSBs. Knockout of Meiok21 decreases the numbers of HSF2BP and DMC1/RAD51 foci, disrupting DSB repair, synapsis and crossover recombination and finally causing male infertility. Therefore, MEIOK21 is a novel recombination factor and probably mediates DMC1/RAD51 recruitment to ssDNA or their stability on chromosomes through physical interaction with HSF2BP.

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