Meiosis-specific prophase-like pathway controls cleavage-independent release of cohesin by Wapl phosphorylation

AbstractSister chromatid cohesion on chromosome arms is essential for the segregation of homologous chromosomes during meiosis I while it is dispensable for sister chromatid separation during mitosis. It was assumed that, unlike the situation in mitosis, chromosome arms retain cohesion prior to onset of anaphase-I. Paradoxically, reduced immunostaining signals of meiosis-specific cohesin, including the kleisin Rec8, from the chromosomes were observed during late prophase-I of budding yeast. This decrease is seen in the absence of Rec8 cleavage and depends on condensin-mediated recruitment of Polo-like kinase (PLK/Cdc5). In this study, we confirmed that this release indeed accompanies the dissociation of acetylated Smc3 as well as Rec8 from meiotic chromosomes during late prophase-I. This release requires, in addition to PLK, the cohesin regulator, Wapl (Rad61/Wpl1 in yeast), and Dbf4-dependent Cdc7 kinase (DDK). Meiosis-specific phosphorylation of Rad61/Wpl1 and Rec8 by PLK and DDK collaboratively promote this release. This process is similar to the vertebrate “prophase” pathway for cohesin release during G2 phase and pro-metaphase. In yeast, meiotic cohesin release coincides with PLK-dependent compaction of chromosomes in late meiotic prophase-I. We suggest that yeast uses this highly regulated cleavage-independent pathway to remove cohesin during late prophase-I to facilitate morphogenesis of condensed metaphase-I chromosomes.Author SummaryIn meiosis the life and health of future generations is decided upon. Any failure in chromosome segregation has a detrimental impact. Therefore, it is currently believed that the physical connections between homologous chromosomes are maintained by meiotic cohesin with exceptional stability. Indeed, it was shown that cohesive cohesin does not show an appreciable turnover during long periods in oocyte development. In this context, it was long assumed but not properly investigated, that the prophase pathway for cohesin release would be specific to mitotic cells and will be safely suppressed during meiosis so as not to endanger the valuable chromosome connections. However, a previous study on budding yeast meiosis suggests the presence of cleavage-independent pathway of cohesin release during late prophase-I. In the work presented here we confirmed that the prophase pathway is not suppressed during meiosis, at least in budding yeast and showed that this cleavage-independent release is regulated by meiosis-specific phosphorylation of two cohesin subunits, Rec8 and Rad61(Wapl) by two cell-cycle regulators, PLK and DDK. Our results suggest that late meiotic prophase-I actively controls cohesin dynamics on meiotic chromosomes for chromosome segregation.

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akirin is required for diakinesis bivalent structure and synaptonemal complex disassembly at meiotic prophase I

Molecular Biology of the Cell ◽

10.1091/mbc.e12-11-0841 ◽

2013 ◽

Vol 24 (7) ◽

pp. 1053-1067 ◽

Cited By ~ 25

Author(s):

Amy M. Clemons ◽

Heather M. Brockway ◽

Yizhi Yin ◽

Bhavatharini Kasinathan ◽

Yaron S. Butterfield ◽

...

Keyword(s):

Synaptonemal Complex ◽

Meiotic Prophase ◽

Chromosome Condensation ◽

Late Prophase ◽

Homologous Chromosomes ◽

Prophase I ◽

Meiotic Prophase I ◽

Evolutionarily Conserved ◽

Key Events

During meiosis, evolutionarily conserved mechanisms regulate chromosome remodeling, leading to the formation of a tight bivalent structure. This bivalent, a linked pair of homologous chromosomes, is essential for proper chromosome segregation in meiosis. The formation of a tight bivalent involves chromosome condensation and restructuring around the crossover. The synaptonemal complex (SC), which mediates homologous chromosome association before crossover formation, disassembles concurrently with increased condensation during bivalent remodeling. Both chromosome condensation and SC disassembly are likely critical steps in acquiring functional bivalent structure. The mechanisms controlling SC disassembly, however, remain unclear. Here we identify akir-1 as a gene involved in key events of meiotic prophase I in Caenorhabditis elegans. AKIR-1 is a protein conserved among metazoans that lacks any previously known function in meiosis. We show that akir-1 mutants exhibit severe meiotic defects in late prophase I, including improper disassembly of the SC and aberrant chromosome condensation, independently of the condensin complexes. These late-prophase defects then lead to aberrant reconfiguring of the bivalent. The meiotic divisions are delayed in akir-1 mutants and are accompanied by lagging chromosomes. Our analysis therefore provides evidence for an important role of proper SC disassembly in configuring a functional bivalent structure.

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Sister chromatid repair maintains genomic integrity during meiosis in Caenorhabditis elegans

10.1101/2020.07.22.216143 ◽

2020 ◽

Author(s):

Erik Toraason ◽

Cordell Clark ◽

Anna Horacek ◽

Marissa L. Glover ◽

Alina Salagean ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Sister Chromatid ◽

Meiotic Prophase ◽

Genome Integrity ◽

Early Prophase ◽

Dna Breaks ◽

Late Prophase ◽

Exogenous Dna ◽

Prophase I ◽

Meiotic Prophase I

SummaryDuring meiosis, the maintenance of genome integrity is critical for generating viable haploid gametes [1]. In meiotic prophase I, double-strand DNA breaks (DSBs) are induced and a subset of these DSBs are repaired as interhomolog crossovers to ensure proper chromosome segregation. DSBs in excess of the permitted number of crossovers must be repaired by other pathways to ensure genome integrity [2]. To determine if the sister chromatid is engaged for meiotic DSB repair during oogenesis, we developed an assay to detect sister chromatid repair events at a defined DSB site during Caenorhabditis elegans meiosis. Using this assay, we directly demonstrate that the sister chromatid is available as a meiotic repair template for both crossover and noncrossover recombination, with noncrossovers being the predominant recombination outcome. We additionally find that the sister chromatid is the exclusive recombination partner for DSBs during late meiotic prophase I. Analysis of noncrossover conversion tract sequences reveals that DSBs are processed similarly throughout prophase I and recombination intermediates remain central around the DSB site. Further, we demonstrate that the SMC-5/6 complex is required for long conversion tracts in early prophase I and intersister crossovers during late meiotic prophase I; whereas, the XPF-1 nuclease is required only in late prophase to promote sister chromatid repair. In response to exogenous DNA damage at different stages of meiosis, we find that mutants for SMC-5/6 and XPF-1 have differential effects on progeny viability. Overall, we propose that SMC-5/6 both processes recombination intermediates and promotes sister chromatid repair within meiotic prophase I, while XPF-1 is required as an intersister resolvase only in late prophase I.

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Micromanipulation of prophase I chromosomes from mouse spermatocytes reveals high stiffness and gel-like chromatin organization

10.1101/2020.08.31.276402 ◽

2020 ◽

Author(s):

Ronald Biggs ◽

Ning Liu ◽

Yiheng Peng ◽

John F. Marko ◽

Huanyu Qiao

Keyword(s):

Meiotic Prophase ◽

Central Element ◽

Critical Event ◽

Mitotic Chromosomes ◽

Large Protein ◽

Homologous Chromosomes ◽

Prophase I ◽

Meiotic Prophase I ◽

Meiotic Chromosomes ◽

Genetic Mutants

Meiosis produces four haploid cells after two successive divisions in sexually reproducing organisms. A critical event during meiosis is construction of the synaptonemal complex (SC), a large, protein-based bridge that physically links homologous chromosomes. The SC facilitates meiotic recombination, chromosome compaction, and the eventual separation of homologous chromosomes at metaphase I. We present experiments directly measuring physical properties of captured mammalian meiotic prophase I chromosomes. Mouse meiotic chromosomes are about ten-fold stiffer than somatic mitotic chromosomes, even for genetic mutants lacking SYCP1, the central element of the SC. Meiotic chromosomes dissolve when treated with nucleases, but only weaken when treated with proteases, suggesting that the SC is not rigidly connected, and that meiotic prophase I chromosomes are a gel meshwork of chromatin, similar to mitotic chromosomes. These results are consistent with a liquid- or liquid-crystal SC, but with SC-chromatin stiff enough to mechanically drive crossover interference.

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Micromanipulation of prophase I chromosomes from mouse spermatocytes reveals high stiffness and gel-like chromatin organization

Communications Biology ◽

10.1038/s42003-020-01265-w ◽

2020 ◽

Vol 3 (1) ◽

Author(s):

Ronald J. Biggs ◽

Ning Liu ◽

Yiheng Peng ◽

John F. Marko ◽

Huanyu Qiao

Keyword(s):

Meiotic Prophase ◽

Central Element ◽

Critical Event ◽

Mitotic Chromosomes ◽

Large Protein ◽

Homologous Chromosomes ◽

Prophase I ◽

Meiotic Prophase I ◽

Meiotic Chromosomes ◽

Genetic Mutants

Abstract Meiosis produces four haploid cells after two successive divisions in sexually reproducing organisms. A critical event during meiosis is construction of the synaptonemal complex (SC), a large, protein-based bridge that physically links homologous chromosomes. The SC facilitates meiotic recombination, chromosome compaction, and the eventual separation of homologous chromosomes at metaphase I. We present experiments directly measuring physical properties of captured mammalian meiotic prophase I chromosomes. Mouse meiotic chromosomes are about ten-fold stiffer than somatic mitotic chromosomes, even for genetic mutants lacking SYCP1, the central element of the SC. Meiotic chromosomes dissolve when treated with nucleases, but only weaken when treated with proteases, suggesting that the SC is not rigidly connected, and that meiotic prophase I chromosomes are a gel meshwork of chromatin, similar to mitotic chromosomes. These results are consistent with a liquid- or liquid-crystal SC, but with SC-chromatin stiff enough to mechanically drive crossover interference.

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Mammalian Protein SCP1 Forms Synaptonemal Complex-like Structures in the Absence of Meiotic Chromosomes

Molecular Biology of the Cell ◽

10.1091/mbc.e04-09-0771 ◽

2005 ◽

Vol 16 (1) ◽

pp. 212-217 ◽

Cited By ~ 65

Author(s):

Rupert Öllinger ◽

Manfred Alsheimer ◽

Ricardo Benavente

Keyword(s):

Chromosome Segregation ◽

Meiotic Prophase ◽

Experimental Conditions ◽

Homologous Chromosomes ◽

Meiotic Chromosomes ◽

Heterologous System ◽

Primary Determinant ◽

Specific Proteins ◽

Mammalian Protein

Synaptonemal complexes (SCs) are evolutionary conserved, meiosis-specific structures that play a central role in synapsis of homologous chromosomes, chiasmata distribution, and chromosome segregation. However, it is still for the most part unclear how SCs do assemble during meiotic prophase. Major components of mammalian SCs are the meiosis-specific proteins SCP1, 2, and 3. To investigate the role of SCP1 in SC assembly, we expressed SCP1 in a heterologous system, i.e., in COS-7 cells that normally do not express SC proteins. Notably, under these experimental conditions SCP1 is able to form structures that closely resemble SCs (i.e., polycomplexes). Moreover, we show that mutations that modify the length of the central α-helical domain of SCP1 influence the width of polycomplexes. Finally, we demonstrate that deletions of the nonhelical N- or C-termini both affect polycomplex assembly, although in a different manner. We conclude that SCP1 is a primary determinant of SC assembly that plays a key role in synapsis of homologous chromosomes.

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Speedy A–Cdk2 binding mediates initial telomere–nuclear envelope attachment during meiotic prophase I independent of Cdk2 activation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1618465114 ◽

2016 ◽

Vol 114 (3) ◽

pp. 592-597 ◽

Cited By ~ 25

Author(s):

Zhaowei Tu ◽

Mustafa Bilal Bayazit ◽

Hongbin Liu ◽

Jingjing Zhang ◽

Kiran Busayavalasa ◽

...

Keyword(s):

Nuclear Envelope ◽

Germ Cells ◽

Meiotic Prophase ◽

Homologous Pairing ◽

Male And Female ◽

Homologous Chromosomes ◽

Cyclin Dependent Kinases ◽

Prophase I ◽

Meiotic Prophase I ◽

Localization Domain

Telomere attachment to the nuclear envelope (NE) is a prerequisite for chromosome movement during meiotic prophase I that is required for pairing of homologous chromosomes, synapsis, and homologous recombination. Here we show that Speedy A, a noncanonical activator of cyclin-dependent kinases (Cdks), is specifically localized to telomeres in prophase I male and female germ cells in mice, and plays an essential role in the telomere–NE attachment. Deletion of Spdya in mice disrupts telomere–NE attachment, and this impairs homologous pairing and synapsis and leads to zygotene arrest in male and female germ cells. In addition, we have identified a telomere localization domain on Speedy A covering the distal N terminus and the Cdk2-binding Ringo domain, and this domain is essential for the localization of Speedy A to telomeres. Furthermore, we found that the binding of Cdk2 to Speedy A is indispensable for Cdk2’s localization on telomeres, suggesting that Speedy A and Cdk2 might be the initial components that are recruited to the NE for forming the meiotic telomere complex. However, Speedy A-Cdk2–mediated telomere–NE attachment is independent of Cdk2 activation. Our results thus indicate that Speedy A and Cdk2 might mediate the initial telomere–NE attachment for the efficient assembly of the telomere complex that is essential for meiotic prophase I progression.

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Meiotic Chromosome Contacts as a Plausible Prelude for Robertsonian Translocations

Genes ◽

10.3390/genes11040386 ◽

2020 ◽

Vol 11 (4) ◽

pp. 386 ◽

Cited By ~ 5

Author(s):

Sergey Matveevsky ◽

Oxana Kolomiets ◽

Aleksey Bogdanov ◽

Elena Alpeeva ◽

Irina Bakloushinskaya

Keyword(s):

Meiotic Prophase ◽

Meiotic Chromosome ◽

Immunocytochemical Staining ◽

Robertsonian Translocations ◽

Homologous Chromosomes ◽

Mechanism Model ◽

Prophase I ◽

Meiotic Prophase I ◽

Translocation Mechanism ◽

Mole Vole

Robertsonian translocations are common chromosomal alterations. Chromosome variability affects human health and natural evolution. Despite the significance of such mutations, no mechanisms explaining the emergence of such translocations have yet been demonstrated. Several models have explored possible changes in interphase nuclei. Evidence for non-homologous chromosomes end joining in meiosis is scarce, and is often limited to uncovering mechanisms in damaged cells only. This study presents a primarily qualitative analysis of contacts of non-homologous chromosomes by short arms, during meiotic prophase I in the mole vole, Ellobius alaicus, a species with a variable karyotype, due to Robertsonian translocations. Immunocytochemical staining of spermatocytes demonstrated the presence of four contact types for non-homologous chromosomes in meiotic prophase I: (1) proximity, (2) touching, (3) anchoring/tethering, and (4) fusion. Our results suggest distinct mechanisms for chromosomal interactions in meiosis. Thus, we propose to change the translocation mechanism model from ‘contact first’ to ‘contact first in meiosis’.

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The conserved Cdc14 phosphatase ensures effective resolution of meiotic recombination intermediates

10.1101/571083 ◽

2019 ◽

Author(s):

Paula Alonso-Ramos ◽

David Álvarez-Melo ◽

Katerina Strouhalova ◽

Carolina Pascual-Silva ◽

George B. Garside ◽

...

Keyword(s):

Chromosome Segregation ◽

Sister Chromatid ◽

Meiotic Recombination ◽

Meiotic Division ◽

Budding Yeast ◽

Direct Role ◽

Independent Manner ◽

Prophase I ◽

New Findings ◽

Yeast Meiosis

AbstractMeiotic defects derived from incorrect DNA repair during gametogenesis can lead to mutations, aneuploidies and infertility. Effective and coordinated resolution of meiotic recombination intermediates is necessary to accomplish both rounds of successful chromosome segregation. Cdc14 is an evolutionarily conserved dual-specificity phosphatase required for mitotic exit and meiotic progression. Mutations that inactivate the phosphatase lead to meiotic failure. Here, we have identified previously undescribed roles of Cdc14 in ensuring correct meiotic recombination. We found that recombination intermediates accumulate during prophase I when Cdc14 is depleted. Furthermore, Cdc14 plays a role in correct homolog disjunction at the end of anaphase I, both by modulating the timely removal of arm-cohesion between sister chromatids and by promoting elimination of SPO11-dependent entanglements. We also demonstrate that Cdc14 is required for correct sister chromatid segregation during the second meiotic division, independent of centromeric cohesion but dependent on the correct reduplication of SPBs during meiosis II, and on the activity of the Holliday Junction resolvase Yen1/GEN1. Timely activation of Yen1/GEN1 in anaphase I and II is impaired in the meiosis defective allele, cdc143HA. Based on these new findings, we propose previously undescribed functions of Cdc14 in the regulation of meiotic recombination; roles that are independent of sister chromatid cohesion, spindle dynamics and the metabolism of gamete morphogenesis.Author SummaryMeiotic recombination is fundamental for sexual reproduction, with efficient and orchestrated resolution of recombination intermediates critical for correct chromosome segregation. Homologous recombination is initiated by the introduction of programmed DNA Double-Strand Breakds (DSBs) followed by the formation of complex branched DNA intermediates, including double Holliday Junctions (dHJs). These recombination intermediates are eventually repaired into crossover or non-crossover products. In some cases, unresolved recombination intermediates, or toxic repair products, might persist until the metaphase to anaphase transition, requiring a set of late-acting repair enzymes to process them. Unrestrained activity of these enzymes, however, is equally detrimental for genome integrity, thus several layers of regulation tightly control them. For example, in budding yeast meiosis, Yen1/GEN1 is mainly activated during the second meiotic division, although how it is activated is unknown. Here, we have identified that the phosphatase Cdc14 is required during meiotic divisions for timely nuclear localization and activation of Yen1 in budding yeast meiosis. Additionally, we have been able to identify previously undescribed roles of Cdc14 in controlling meiotic recombination. Strikingly, we found that levels of recombination intermediates increase during prophase I in cdc14 meiotic deficient cells, indicating that Cdc14 plays a direct role in monitoring meiotic DSB repair, possibly in Yen1-independent manner. Resolution of recombination intermediates in the absence of Cdc14 is dependent on SGS1 and MUS81/MMS4, otherwise accumulating different types of aberrant recombination intermediates and a highly reduced efficiency in CO formation. Deficient resolution of JMs in cdc14 meiotic cells, together with difficulties in SPB reduplication, likely contribute to the missegregation problems observed during the second meiotic division.

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FBXO47 regulates telomere-inner nuclear envelope integration by stabilizing TRF2 during meiosis

Nucleic Acids Research ◽

10.1093/nar/gkz992 ◽

2019 ◽

Author(s):

Rong Hua ◽

Huafang Wei ◽

Chao Liu ◽

Yue Zhang ◽

Siyu Liu ◽

...

Keyword(s):

Nuclear Envelope ◽

Synaptonemal Complex ◽

Meiotic Prophase ◽

Homologous Chromosomes ◽

Prophase I ◽

Shelterin Complex ◽

Meiotic Prophase I ◽

F Box Protein ◽

Bouquet Stage

Abstract During meiosis, telomere attachment to the inner nuclear envelope is required for proper pairing of homologous chromosomes and recombination. Here, we identified F-box protein 47 (FBXO47) as a regulator of the telomeric shelterin complex that is specifically expressed during meiotic prophase I. Knockout of Fbxo47 in mice leads to infertility in males. We found that the Fbxo47 deficient spermatocytes are unable to form a complete synaptonemal complex. FBXO47 interacts with TRF1/2, and the disruption of Fbxo47 destabilizes TRF2, leading to unstable telomere attachment and slow traversing through the bouquet stage. Our findings uncover a novel mechanism of FBXO47 in telomeric shelterin subunit stabilization during meiosis.

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DNA Environment of Centromeres and Non-homologous Chromosomes Interactions in Mouse

10.20944/preprints202111.0436.v1 ◽

2021 ◽

Author(s):

Victor Spangenberg ◽

Losev Michail ◽

Volkhin Ilya ◽

Svetlana Smirnova ◽

Nikitin Pavel ◽

...

Keyword(s):

Y Chromosome ◽

X Chromosome ◽

Satellite Dna ◽

Meiotic Prophase ◽

Centromeric Region ◽

Autosomal Bivalents ◽

Homologous Chromosomes ◽

Prophase I ◽

Meiotic Prophase I ◽

Minor Satellite

Pericentromeric regions of chromosomes enriched in tandemly repeated satellite DNA although representing a significant part of eukaryotic genomes are still understudied mainly due to interdisciplinary knowledge gaps. Recent studies suggest their important role in genome regulation, karyotype stability and evolution. Thus, the idea of satellite DNA as a junk part of the genome was refuted. Integration of data about molecular composition, chromosome behaviour and details of in situ organization of pericentromeric regions is of great interest. The objective of this work was a cytogenetic analysis of the interactions of pericentromeric regions non-homologous chromosomes in mouse spermatocytes using immuno-FISH. We analysed two events: the associations between cerntomeric regions of X chromosome and autosomes, and associations between centromeric regions of autosomal bivalents forming chromocenters. We conclude that X chromosome form temporary synaptic associations with different autosomes in early meiotic prophase I which normally can be found at pachytene-diplotene without signs of pachytene arrest. These associations are formed between the satellite DNA-enriched centomeric regions of X chromosome and different autosomes but not involve the satellite-poor centromeric region of Y-chromosome. We suggest the mechanism of X chromosome competitive replacement from such associations during synaptic correction. We showed that centromeric region of the X chromosome remains free of γH2Ax-dependent chromatin inactivation, while Y chromosome is completely inactivated. This findings highlights the predominant role of associations between satellite DNA-enriched regions of different chromosomes including X. We assume that X-autosome temporary associations is a manifestation of an additional synaptic disorders checkpoint. These associations are normally corrected before the late diplotene. We revealed that the intense spreading conditions applied to the spermatocytes I nuclei did not lead to destruction of stretched chromatin fibers i.e. elongated chromocenters enriched in satellite DNA. Revealed by us tight associations between pericentromeric regions of different autosomal bivalents and X chromosome may represent the basis for repeat stability maintenance in autosomes an X chromosome. The consequences of our findings are discussed. We obtained the preparations of mouse spermatocytes nuclei in the meiotic prophase I using two approaches: standard and extremely intense surface spread techniques. Using immuno-FISH we visualized tandemly repeated mouse Major and Minor satellite DNA located in the pericentromeric regions of chromosomes and performed a morphological comparison of the standard- and intensely spreaded meiotic nuclei. Based on our results, we assume the remarkable strength of the chromocenter-mediated associations, “chromatin “bridges”, between different bivalents at the pachytene and diplotene stages. We have demonstrated that the chromocenter “bridges” between the centromeric ends of meiotic bivalents are enriched in both tandemly repeated Major and Minor satellite DNA. Association of centromeric regions of autosomal bivalents and X-chromosome but not with Y-chromosome correlates with the absence of Major and Minor satellites on Y-chromosome. We suggest that revealed tight associations between pericentromeric regions of bivalents may represent the network-like system providing dynamic stability of chromosomal territories, as well as add new data for the hypothesis of ectopic recombination in these regions which supports sequence homogeneity between non-homologous chromosomes and does not contradict the meiotic restrictions imposed by the crossing-over interference near centromeres. We conclude that nuclear architecture in meio-sis may play an essential role in contacts between the non-homologous chromosomes providing the specific characteristics of pericentromeric DNA.

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