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

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.

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

10.1101/2021.08.13.456249 ◽

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.

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

Science ◽

10.1126/science.aaf4778 ◽

2017 ◽

Vol 355 (6323) ◽

pp. 408-411 ◽

Cited By ~ 46

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.

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

The Journal of Cell Biology ◽

10.1083/jcb.139.2.459 ◽

1997 ◽

Vol 139 (2) ◽

pp. 459-467 ◽

Cited By ~ 29

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.

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CRISPR targeting of MEIOTIC-TOPOISOMERASE VIB-dCas9 to a recombination hotspot is insufficient to increase crossover frequency in Arabidopsis

10.1101/2021.02.01.429210 ◽

2021 ◽

Author(s):

Nataliya E. Yelina ◽

Sabrina Gonzalez-Jorge ◽

Dominique Hirsz ◽

Ziyi Yang ◽

Ian R. Henderson

Keyword(s):

Meiotic Recombination ◽

Crop Improvement ◽

Double Strand Breaks ◽

Crossover Frequency ◽

Dna Double Strand Breaks ◽

Crop Breeding ◽

Catalytic Subunits ◽

Strand Breaks ◽

Homologous Chromosomes ◽

Meiotic Crossover

AbstractDuring meiosis, homologous chromosomes pair and recombine, which can result in reciprocal crossovers that increase genetic diversity. Crossovers are unevenly distributed along eukaryote chromosomes and show repression in heterochromatin and the centromeres. Within the chromosome arms crossovers are often concentrated in hotspots, which are typically in the kilobase range. The uneven distribution of crossovers along chromosomes, together with their low number per meiosis, creates a limitation during crop breeding, where recombination can be beneficial. Therefore, targeting crossovers to specific genome locations has the potential to accelerate crop improvement. In plants, meiotic crossovers are initiated by DNA double strand breaks (DSBs) that are catalysed by SPO11 complexes, which consist of two catalytic (SPO11-1 and SPO11-2) and two non-catalytic subunits (MTOPVIB). We used the model plant Arabidopsis thaliana to target a dCas9-MTOPVIB fusion protein to the 3a crossover hotspot via CRISPR. We observed that this was insufficient to significantly change meiotic crossover frequency or pattern within 3a. We discuss the implications of our findings for targeting meiotic recombination within plant genomes.

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Heat Stress Interferes with Formation of Double-Strand Breaks and Homolog Synapsis in Arabidopsis thaliana

10.1101/2020.10.02.324269 ◽

2020 ◽

Author(s):

Yingjie Ning ◽

Qingpei Liu ◽

Chong Wang ◽

Erdai Qin ◽

Zhihua Wu ◽

...

Keyword(s):

Heat Stress ◽

Central Element ◽

Double Strand Breaks ◽

Genomic Diversity ◽

Rt Pcr ◽

Genetic Studies ◽

Lateral Element ◽

Strand Breaks ◽

Downstream Effects ◽

Chromosome Axis

AbstractMeiotic recombination (MR) drives novel combination of alleles and contributes to genomic diversity in eukaryotes. In this study, we showed that heat stress (36-38°C) over fertile threshold fully abolished crossover (CO) formation in Arabidopsis. Cytological and genetic studies in wild-type plants, and the syn1 and rad51 mutants suggested that heat stress reduces generation of SPO11-dependent double-strand breaks (DSBs). In support, the abundance of recombinase DMC1, which is required for MR-specific DSB repair, was significantly reduced under heat stress. In addition, we showed that high temperatures induced disassembly and/or instability of ASY4-but not SYN1-mediated chromosome axis. At the same time, ASY1-associated lateral element of synaptonemal complex (SC) was partially affected, while the ZYP1-dependent central element of SC was disrupted, indicating that heat stress impairs SC formation. Moreover, quantitative RT-PCR revealed that genes involved in DSB formation; e.g. SPO11-1, PRD1, 2 and 3, were not impacted; however, recombinase RAD51 and chromosome axis factors ASY3 and ASY4 were significantly downregulated under heat stress. Taken together, these findings revealed that heat stress inhibits MR via compromised DSB formation and homolog synapsis, which are possible downstream effects of the impacted chromosome axis. Our study thus provides evidence shedding light on how increase of environmental temperature influences MR in Arabidopsis.

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Mnd1/Hop2 Facilitates Dmc1-Dependent Interhomolog Crossover Formation in Meiosis of Budding Yeast

Molecular and Cellular Biology ◽

10.1128/mcb.26.8.2913-2923.2006 ◽

2006 ◽

Vol 26 (8) ◽

pp. 2913-2923 ◽

Cited By ~ 31

Author(s):

Jill M. Henry ◽

Raymond Camahort ◽

Douglas A. Rice ◽

Laurence Florens ◽

Selene K. Swanson ◽

...

Keyword(s):

Meiotic Recombination ◽

Double Mutant ◽

Repetitive Sequences ◽

Double Strand Breaks ◽

Genomic Integrity ◽

Dna Interactions ◽

Strand Breaks ◽

Homologous Chromosomes ◽

Meiotic Crossover ◽

Strand Invasion

ABSTRACT During meiosis, each chromosome must pair with its homolog and undergo meiotic crossover recombination in order to segregate properly at the first meiotic division. Recombination in meiosis in Saccharomyces cerevisiae relies on two Escherichia coli recA homologs, Rad51 and Dmc1, as well as the more recently discovered heterodimer Mnd1/Hop2. Meiotic recombination in S. cerevisiae mnd1 and hop2 single mutants is initiated via double-strand breaks (DSBs) but does not progress beyond this stage; heteroduplex DNA, joint molecules, and crossovers are not detected. Whereas hop2 and mnd1 single mutants are profoundly recombination defective, we show that mnd1 rad51, hop2 rad51, and mnd1 rad17 double mutants are able to carry out crossover recombination. Interestingly, noncrossover recombination is absent, indicating a role for Mnd1/Hop2 in the designation of DSBs for noncrossover recombination. We demonstrate that in the rad51 mnd1 double mutant, recombination is more likely to occur between repetitive sequences on nonhomologous chromosomes. Our results support a model in which Mnd1/Hop2 is required for DNA-DNA interactions that help ensure Dmc1-mediated stable strand invasion between homologous chromosomes, thereby preserving genomic integrity.

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

Science Advances ◽

10.1126/sciadv.aau9780 ◽

2019 ◽

Vol 5 (1) ◽

pp. eaau9780 ◽

Cited By ~ 3

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.

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Coupling crossover and synaptonemal complex in meiosis

Genes & Development ◽

10.1101/gad.349286.121 ◽

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.

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The bakers’s yeast Msh4-Msh5 associates with double-strand break hotspots and chromosome axis during meiosis to promote crossovers

10.1101/2020.07.24.219295 ◽

2020 ◽

Author(s):

Krishnaprasad G. Nandanan ◽

Ajith V. Pankajam ◽

Sagar Salim ◽

Miki Shinohara ◽

Gen Lin ◽

...

Keyword(s):

Mismatch Repair ◽

Baker’S Yeast ◽

Double Strand Breaks ◽

Holliday Junction ◽

Baker's Yeast ◽

Strand Breaks ◽

Homologous Chromosomes ◽

Genome Wide ◽

Chromosome Axis

ABSTRACTSegregation of homologous chromosomes during the first meiotic division requires at least one obligate crossover/exchange event between the homolog pairs. In the baker’s yeast Saccharomyces cerevisiae and mammals, the mismatch repair-related factors, Msh4-Msh5 and Mlh1-Mlh3 generate the majority of the meiotic crossovers from programmed double-strand breaks (DSBs). To understand the mechanistic role of Msh4-Msh5 in meiotic crossing over, we performed genome-wide ChIP-sequencing and cytological analysis of the Msh5 protein in cells synchronized for meiosis. We observe that Msh5 associates with DSB hotspots, chromosome axis, and centromeres. We found that the initial recruitment of Msh4-Msh5 occurs following DSB resection. A two-step Msh5 binding pattern was observed: an early weak binding at DSB hotspots followed by enhanced late binding upon the formation of double Holliday junction structures. Msh5 association with the chromosome axis is Red1 dependent, while Msh5 association with the DSB hotspots and axis is dependent on DSB formation by Spo11. Msh5 binding was enhanced at strong DSB hotspots consistent with a role for DSB frequency in promoting Msh5 binding. These data on the in vivo localization of Msh5 during meiosis have implications for how Msh4-Msh5 may work with other crossover and synapsis promoting factors to ensure Holliday junction resolution at the chromosome axis.AUTHOR SUMMARYDuring meiosis, crossovers facilitate physical linkages between homologous chromosomes that ensure their accurate segregation. Meiotic crossovers are initiated from programmed DNA double-strand breaks (DSBs). In the baker’s yeast and mammals, DSBs are repaired into crossovers primarily through a pathway involving the highly conserved mismatch repair related Msh4-Msh5 complex along with other crossover promoting factors. In vitro and physical studies suggest that the Msh4-Msh5 heterodimer facilitates meiotic crossover formation by stabilizing Holliday junctions. We investigated the genome-wide in vivo binding sites of Msh5 during meiotic progression. Msh5 was enriched at DSB hotspots, chromosome axis, and centromere sites. Our results suggest Msh5 associates with both DSB sites on the chromosomal loops and with the chromosome axis to promote crossover formation. These results on the in vivo dynamic localization of the Msh5 protein provide novel insights into how the Msh4-Msh5 complex may work with other crossover and synapsis promoting factors to facilitate crossover formation.

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Sycp1 Is Not Required for Subtelomeric DNA Double-Strand Breaks but Is Required for Homologous Alignment in Zebrafish Spermatocytes

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.664377 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yukiko Imai ◽

Kenji Saito ◽

Kazumasa Takemoto ◽

Fabien Velilla ◽

Toshihiro Kawasaki ◽

...

Keyword(s):

Synaptonemal Complex ◽

Central Element ◽

Double Strand Breaks ◽

Dependent Manner ◽

Wild Type ◽

Dna Double Strand Breaks ◽

Gene Encoding ◽

Strand Breaks ◽

Stop Mutation ◽

Filament Protein

In meiotic prophase I, homologous chromosomes are bound together by the synaptonemal complex, in which two axial elements are connected by transverse filaments and central element proteins. In human and zebrafish spermatocytes, homologous recombination and assembly of the synaptonemal complex initiate predominantly near telomeres. In mice, synapsis is not required for meiotic double-strand breaks (DSBs) and homolog alignment but is required for DSB repair; however, the interplay of these meiotic events in the context of peritelomeric bias remains unclear. In this study, we identified a premature stop mutation in the zebrafish gene encoding the transverse filament protein Sycp1. Insycp1mutant zebrafish spermatocytes, axial elements were formed and paired at chromosome ends between homologs during early to mid-zygonema. However, they did not synapse, and their associations were mostly lost in late zygotene- or pachytene-like stages. Insycp1mutant spermatocytes, γH2AX signals were observed, and Dmc1/Rad51 and RPA signals appeared predominantly near telomeres, resembling wild-type phenotypes. We observed persistent localization of Hormad1 along the axis insycp1mutant spermatocytes, while the majority of Iho1 signals appeared and disappeared with kinetics similar to those in wild-type spermatocytes. Notably, persistent Iho1 foci were observed inspo11mutant spermatocytes, suggesting that Iho1 dissociation from axes occurs in a DSB-dependent manner. Our results demonstrated that Sycp1 is not required for peritelomeric DSB formation but is necessary for complete pairing of homologs in zebrafish meiosis.

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