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

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.

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

2013 ◽  
Vol 24 (7) ◽  
pp. 1053-1067 ◽  
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.

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

2016 ◽  
Vol 114 (3) ◽  
pp. 592-597 ◽  
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.

scholarly journals Lateral Elements Inside Synaptonemal Complex-Like Polycomplexes in ndt80 Mutants of Yeast Bind DNA

Genetics ◽  
2003 ◽  
Vol 163 (2) ◽  
pp. 539-544 ◽  
Author(s):  
Hasanuzzaman Bhuiyan ◽  
Gunilla Dahlfors ◽  
Karin Schmekel
Keyword(s):  
In Situ Hybridization ◽  
Electron Microscope ◽  
Synaptonemal Complex ◽  
Immunoelectron Microscopy ◽  
Meiotic Prophase ◽  
Lateral Element ◽  
Homologous Chromosomes ◽  
Meiotic Prophase I ◽  
Dna Antibodies

Abstract The synaptonemal complex (SC) keeps the synapsed homologous chromosomes together during pachytene in meiotic prophase I. Structures that resemble stacks of SCs, polycomplexes, are sometimes found before or after pachytene. We have investigated ndt80 mutants of yeast, which arrest in pachytene. SCs appear normal in spread chromosome preparations, but are only occasionally found in intact nuclei examined in the electron microscope. Instead, large polycomplexes occur in almost every ndt80 mutant nucleus. Immunoelectron microscopy using DNA antibodies show strong preferential labeling to the lateral element parts of the polycomplexes. In situ hybridization using chromosome-specific probes confirms that the chromosomes in ndt80 mutants are paired and attached to the SCs. Our results suggest that polycomplexes can be involved in binding of chromosomes and possibly also in synapsis.

scholarly journals The CSN/COP9 Signalosome Regulates Synaptonemal Complex Assembly during Meiotic Prophase I of Caenorhabditis elegans

PLoS Genetics ◽  
2014 ◽  
Vol 10 (11) ◽  
pp. e1004757 ◽  
Author(s):  
Heather Brockway ◽  
Nathan Balukoff ◽  
Martha Dean ◽  
Benjamin Alleva ◽  
Sarit Smolikove
Keyword(s):  
Caenorhabditis Elegans ◽  
Synaptonemal Complex ◽  
Meiotic Prophase ◽  
Cop9 Signalosome ◽  
Complex Assembly ◽  
Prophase I ◽  
Meiotic Prophase I

scholarly journals Nuclear Envelope-Associated Chromosome Dynamics during Meiotic Prophase I

2018 ◽  
Vol 5 ◽  
Author(s):  
Xinhua Zeng ◽  
Keqi Li ◽  
Rong Yuan ◽  
Hongfei Gao ◽  
Junling Luo ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Meiotic Prophase ◽  
Chromosome Dynamics ◽  
Prophase I ◽  
Meiotic Prophase I

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

2018 ◽  
Author(s):  
Kiran Challa ◽  
V Ghanim Fajish ◽  
Miki Shinohara ◽  
Franz Klein ◽  
Susan M. Gasser ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Sister Chromatid ◽  
Meiotic Prophase ◽  
Budding Yeast ◽  
Cell Cycle Regulators ◽  
Late Prophase ◽  
Homologous Chromosomes ◽  
Prophase I ◽  
Meiotic Prophase I ◽  
Meiotic Chromosomes

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.

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

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.

scholarly journals Loss of Synaptonemal Complex Protein-1, a Synaptonemal Complex Protein, Contributes to the Initiation of Follicular Assembly in the Developing Rat Ovary

Endocrinology ◽  
2005 ◽  
Vol 146 (12) ◽  
pp. 5267-5277 ◽  
Author(s):  
Alfonso Paredes ◽  
Cecilia Garcia-Rudaz ◽  
Bredford Kerr ◽  
Veronica Tapia ◽  
Gregory A. Dissen ◽  
...  
Keyword(s):  
Synaptonemal Complex ◽  
Meiotic Prophase ◽  
Primordial Follicles ◽  
Diplotene Stage ◽  
Prophase I ◽  
Meiotic Prophase I ◽  
Complex Protein ◽  
Synaptonemal Complex Protein ◽  
Rat Ovary ◽  
Developing Rat

In the rat ovary, germ and somatic cells become organized into primordial follicles 48–72 h after birth. Although several genes have been implicated in the control of early follicular growth, less is known about the factors involved in the formation of primordial follicles. Using the method of differential display of mRNAs, we found several genes differentially expressed at the time of follicular assembly. One of them encodes synaptonemal complex protein-1 (SCP1), a core component of the protein complex that maintains recombining chromosomes together during prophase I of the first meiotic division in germ cells. This association, evident during the pachytene stage, ends when chromosomal desynapsis begins in the diplotene stage at the end of prophase I. Oocytes become arrested in the diplotene/dictate stage before becoming enclosed into primordial follicles, suggesting that oocytes must complete meiotic prophase I before becoming competent to direct follicle assembly. We now show that attainment of the diplotene stage results in follicular formation. In developing rat ovaries, SCP1 mRNA expression is confined to oocytes and decreases precipitously within 24 h after birth, preceding the organization of primordial follicles. The premature loss of SCP1, achieved via treatment with an antisense oligodeoxynucleotide targeting SCP1 mRNA, resulted in more oocytes reaching the diplotene stage, as evidenced by a decrease in the number of oocytes containing germ cell nuclear antigen-1 (a nuclear protein whose expression ceases in diplotene) and an increase in the number of oocytes expressing MSY2 (a cytoplasmic Y box protein expressed in oocytes that have become arrested in diplotene). SCP1-deficient ovaries exhibited an increased number of newly formed follicles, suggesting that completion of meiotic prophase I endows oocytes with the ability to orchestrate follicular assembly.

scholarly journals Meiotic Chromosome Contacts as a Plausible Prelude for Robertsonian Translocations

Genes ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 386 ◽  
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’.

Sign in / Sign up

Export Citation Format

Share Document