scholarly journals The rec8 gene of Schizosaccharomyces pombe is involved in linear element formation, chromosome pairing and sister-chromatid cohesion during meiosis.

Genetics ◽  
1995 ◽  
Vol 141 (1) ◽  
pp. 61-73
Author(s):  
M Molnar ◽  
J Bähler ◽  
M Sipiczki ◽  
J Kohli
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Chromosome Pairing ◽  
Meiotic Recombination ◽  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Linear Element ◽  
Meiotic Chromosomes ◽  
Sister Chromatids ◽  
Linear Elements ◽  
Chromosome Iii

Abstract The fission yeast Schizosaccharomyces pombe does not form tripartite synaptonemal complexes during meiotic prophase, but axial core-like structures (linear elements). To probe the relationship between meiotic recombination and the structure, pairing, and segregation of meiotic chromosomes, we genetically and cytologically characterized the rec8-110 mutant, which is partially deficient in meiotic recombination. The pattern of spore viability indicates that chromosome segregation is affected in the mutant. A detailed segregational analysis in the rec8-110 mutant revealed more spores disomic for chromosome III than in a wild-type strain. Aberrant segregations are caused by precocious segregation of sister chromatids at meiosis I, rather than by nondisjunction as a consequence of lack of crossovers. In situ hybridization further showed that the sister chromatids are separated prematurely during meiotic prophase. Moreover, the mutant forms aberrant linear elements and shows a shortened meiotic prophase. Meiotic chromosome pairing in interstitial and centromeric regions is strongly impaired in rec8-110, whereas the chromosome ends are less deficient in pairing. We propose that the rec8 gene encodes a protein required for linear element formation and that the different phenotypes of rec8-110 reflect direct and indirect consequences of the absence of regular linear elements.

scholarly journals Topoisomerases modulate the timing of meiotic DNA breakage and chromosome morphogenesis in Saccharomyces cerevisiae

2019 ◽  
Author(s):  
Jonna Heldrich ◽  
Xiaoji Sun ◽  
Luis A. Vale-Silva ◽  
Tovah E. Markowitz ◽  
Andreas Hochwagen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Strand Break ◽  
Temperature Sensitive ◽  
Chromosomal Dna ◽  
Meiotic Chromosomes ◽  
Chromosome Synapsis ◽  
Intergenic Regions

AbstractDuring meiotic prophase, concurrent transcription, recombination, and chromosome synapsis, place substantial topological strain on chromosomal DNA, but the role of topoisomerases in this context remains poorly defined. Here, we analyzed the roles topoisomerases I and II (Top1 and Top2) during meiotic prophase in Saccharomyces cerevisiae. We show that both topoisomerases accumulate primarily in promoter-containing intergenic regions of actively transcribing genes. Enrichment partially overlaps meiotic double-strand break (DSB) hotspots, but disruption of either topoisomerase has different effects during meiotic recombination. TOP1 disruption delays DSB induction and shortens the window of DSB accumulation by an unknown mechanism. By contrast, temperature-sensitive top2-1 mutants accumulate DSBs on synapsed chromosomes and exhibit a marked delay in meiotic chromosome remodeling. This defect results from a delay in recruiting the meiotic chromosome remodeler Pch2/TRIP13 but, unexpectedly, is not due to a loss of Top2 catalytic activity. Instead, mutant Top2-1 protein has reduced contact with chromatin but remains associated with meiotic chromosomes, and we provide evidence that this altered binding is responsible for the delay in chromosome remodeling. Our results imply independent roles for topoisomerases I and II in modulating meiotic recombination.

scholarly journals Nup132 modulates meiotic spindle attachment in fission yeast by regulating kinetochore assembly

2015 ◽  
Vol 211 (2) ◽  
pp. 295-308 ◽  
Author(s):  
Hui-Ju Yang ◽  
Haruhiko Asakawa ◽  
Tokuko Haraguchi ◽  
Yasushi Hiraoka
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Meiotic Prophase ◽  
Spindle Assembly Checkpoint ◽  
Meiotic Spindle ◽  
Spindle Attachment ◽  
Kinetochore Assembly ◽  
Sister Chromatids ◽  
Monopolar Spindle ◽  
Meiosis I

During meiosis, the kinetochore undergoes substantial reorganization to establish monopolar spindle attachment. In the fission yeast Schizosaccharomyces pombe, the KNL1–Spc7-Mis12-Nuf2 (KMN) complex, which constitutes the outer kinetochore, is disassembled during meiotic prophase and is reassembled before meiosis I. Here, we show that the nucleoporin Nup132 is required for timely assembly of the KMN proteins: In the absence of Nup132, Mis12 and Spc7 are precociously assembled at the centromeres during meiotic prophase. In contrast, Nuf2 shows timely dissociation and reappearance at the meiotic centromeres. We further demonstrate that depletion of Nup132 activates the spindle assembly checkpoint in meiosis I, possibly because of the increased incidence of erroneous spindle attachment at sister chromatids. These results suggest that precocious assembly of the kinetochores leads to the meiosis I defects observed in the nup132-disrupted mutant. Thus, we propose that Nup132 plays an important role in establishing monopolar spindle attachment at meiosis I through outer kinetochore reorganization at meiotic prophase.

scholarly journals Dmc1 is a candidate for temperature tolerance during wheat meiosis

2019 ◽  
Author(s):  
Tracie Draeger ◽  
Azahara Martin ◽  
Abdul Kader Alabdullah ◽  
Ali Pendle ◽  
María-Dolores Rey ◽  
...  
Keyword(s):  
High Temperatures ◽  
Chromosome Pairing ◽  
Meiotic Recombination ◽  
Low Temperatures ◽  
Chinese Spring ◽  
Deletion Mutant ◽  
Meiotic Chromosome ◽  
Wheat Chromosome ◽  
Chromosome Synapsis ◽  
Recombination Gene

AbstractWe have assessed the effects of high and low temperatures on meiotic chromosome synapsis and crossover formation in the hexaploid wheat (Triticum aestivum L.) variety ‘Chinese Spring’. At low temperatures, asynapsis and chromosome univalence have been observed before in Chinese Spring lines lacking the long arm of chromosome 5D (5DL), which led to the proposal that 5DL carries a gene (Ltp1) that stabilises wheat chromosome pairing at low temperatures. In the current study, Chinese Spring wild type and 5DL interstitial deletion mutant plants were exposed to low (13°C) or high (30°C) temperatures in controlled environment rooms during a period from premeiotic interphase to early meiosis I. A 5DL deletion mutant was identified whose meiotic chromosomes exhibit extremely high levels of asynapsis and chromosome univalence at metaphase I after seven days at 13°C. This suggests that the mutant, which we name ttmei1 (temperature tolerance in meiosis 1) has a deletion of a gene that, like Ltp1, normally stabilises chromosome pairing at low temperatures. Immunolocalisation of the meiotic proteins ASY1 and ZYP1 on ttmei1 mutants showed that low temperature results in a failure to complete synapsis at pachytene. After 24 hours at 30°C, ttmei1 mutants exhibited a reduced number of crossovers and increased univalence, but to a lesser extent than at 13°C. KASP genotyping revealed that ttmei1 has a 4 Mb deletion in 5DL. Of 41 genes within this deletion region, the strongest candidate for the stabilisation of chromosome pairing at low (and possibly high) temperatures is the meiotic recombination gene Dmc1.Key messageThe meiotic recombination gene Dmc1 on wheat chromosome 5D has been identified as a candidate for the maintenance of normal chromosome synapsis and crossover at low and possibly high temperatures.

Architecture and Dynamics of Meiotic Chromosomes

2021 ◽  
Vol 55 (1) ◽  
Author(s):  
Sarah N. Ur ◽  
Kevin D. Corbett
Keyword(s):  
Meiotic Prophase ◽  
Morphological Changes ◽  
Meiotic Chromosome ◽  
Dna Recombination ◽  
Chromosome Complement ◽  
Annual Review ◽  
Publication Date ◽  
Meiotic Chromosomes ◽  
Crystal Model ◽  
Chromosome Axis

The specialized two-stage meiotic cell division program halves a cell's chromosome complement in preparation for sexual reproduction. This reduction in ploidy requires that in meiotic prophase, each pair of homologous chromosomes (homologs) identify one another and form physical links through DNA recombination. Here, we review recent advances in understanding the complex morphological changes that chromosomes undergo during meiotic prophase to promote homolog identification and crossing over. We focus on the structural maintenance of chromosomes (SMC) family cohesin complexes and the meiotic chromosome axis, which together organize chromosomes and promote recombination. We then discuss the architecture and dynamics of the conserved synaptonemal complex (SC), which assembles between homologs and mediates local and global feedback to ensure high fidelity in meiotic recombination. Finally, we discuss exciting new advances, including mechanisms for boosting recombination on particular chromosomes or chromosomal domains and the implications of a new liquid crystal model for SC assembly and structure. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals A SUMO-ubiquitin relay recruits proteasomes to chromosome axes to regulate meiotic recombination

Science ◽  
2017 ◽  
Vol 355 (6323) ◽  
pp. 403-407 ◽  
Author(s):  
H. B. D. Prasada Rao ◽  
Huanyu Qiao ◽  
Shubhang K. Bhatt ◽  
Logan R. J. Bailey ◽  
Hung D. Tran ◽  
...  
Keyword(s):  
Meiotic Recombination ◽  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Ubiquitin Proteasome System ◽  
Protein Stabilization ◽  
E3 Ligases ◽  
Sumo Conjugation ◽  
Ubiquitin Proteasome

Meiosis produces haploid gametes through a succession of chromosomal events, including pairing, synapsis, and recombination. Mechanisms that orchestrate these events remain poorly understood. We found that the SUMO (small ubiquitin-like modifier)–modification and ubiquitin-proteasome systems regulate the major events of meiotic prophase in mouse. Interdependent localization of SUMO, ubiquitin, and proteasomes along chromosome axes was mediated largely by RNF212 and HEI10, two E3 ligases that are also essential for crossover recombination. RNF212-dependent SUMO conjugation effected a checkpointlike process that stalls recombination by rendering the turnover of a subset of recombination factors dependent on HEI10-mediated ubiquitylation. We propose that SUMO conjugation establishes a precondition for designating crossover sites via selective protein stabilization. Thus, meiotic chromosome axes are hubs for regulated proteolysis via SUMO-dependent control of the ubiquitin-proteasome system.

scholarly journals Meiotic recombination proteins localize to linear elements in Schizosaccharomyces pombe

Chromosoma ◽  
2006 ◽  
Vol 115 (4) ◽  
pp. 330-340 ◽  
Author(s):  
Alexander Lorenz ◽  
Anna Estreicher ◽  
Jürg Kohli ◽  
Josef Loidl
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Recombination Proteins ◽  
Linear Elements

scholarly journals Characterization of rec7, an Early Meiotic Recombination Gene in Schizosaccharomyces pombe

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 519-532 ◽  
Author(s):  
Monika Molnar ◽  
Sandro Parisi ◽  
Yoshito Kakihara ◽  
Hiroshi Nojima ◽  
Ayumu Yamamoto ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
Specific Expression ◽  
Homologous Chromosomes ◽  
Disruption Mutant ◽  
Whole Cells ◽  
Functional Homolog ◽  
Linear Elements ◽  
Meiosis I

Abstract rec7 is involved in intra- and intergenic meiotic recombination in all tested regions of the genome of the fission yeast Schizosaccharomyces pombe. Segregational analysis in a rec7 gene disruption mutant revealed frequent occurrence of two-spored asci. Spores giving rise to diploid colonies were shown to derive from skipping of the second meiotic division. Nondisjunction of homologous chromosomes at the first meiotic division was also frequent. The cytological structures and processes, such as formation of linear elements, pairing of homologous chromosomes, and clustering of telomeres and centromeres, are regular in the mutant. Northern blot experiments revealed meiosis-specific expression of rec7. Screening of a meiotic cDNA library also identified transcripts from the opposite strand in the rec7 region. A Rec7-GFP fusion protein was localized in the nucleus of whole cells before karyogamy, during prophase, and after meiosis I. On spreads of prophase nuclei approximately 50 foci of Rec7-GFP were counted. Some of the observed phenotypes of the disruption mutant and the N-terminal sequence homology suggest that Rec7p is a functional homolog of Rec114p of Saccharomyces cerevisiae. The observed phenotypes of the disruption and the appearance of Rec7-GFP in mating haploid cells and after meiosis I are consistent with Rec7p functions before, during, and after meiotic prophase.

scholarly journals Meiotic disjunction of homologs in Saccharomyces cerevisiae is directed by pairing and recombination of the chromosome arms but not by pairing of the centromeres.

Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 273-287
Author(s):  
R T Surosky ◽  
B K Tye
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Segregation ◽  
Meiotic Chromosome ◽  
Chromosomal Rearrangements ◽  
Normal Chromosome ◽  
Telocentric Chromosome ◽  
Meiotic Chromosomes ◽  
Chromosome Recombination ◽  
Left And Right ◽  
Chromosome Iii

Abstract We explored the behavior of meiotic chromosomes in Saccharomyces cerevisiae by examining the effects of chromosomal rearrangements on the pattern of disjunction and recombination of chromosome III during meiosis. The segregation of deletion chromosomes lacking part or all (telocentric) of one arm was analyzed in the presence of one or two copies of a normal chromosome III. In strains containing one normal and any one deletion chromosome, the two chromosomes disjoined in most meioses. In strains with one normal chromosome and both a left and right arm telocentric chromosome, the two telocentrics preferentially disjoined from the normal chromosome. Homology on one arm was sufficient to direct chromosome disjunction, and two chromosomes could be directed to disjoin from a third. In strains containing one deletion chromosome and two normal chromosomes, the two normal chromosomes preferentially disjoined, but in 4-7% of the tetrads the normal chromosomes cosegregated, disjoining from the deletion chromosome. Recombination between the two normal chromosomes or between the deletion chromosome and a normal chromosome increased the probability that these chromosomes would disjoin, although cosegregation of recombinants was observed. Finally, we observed that a derivative of chromosome III in which the centromeric region was deleted and CEN5 was integrated at another site on the chromosome disjoined from a normal chromosome III with fidelity. These studies demonstrate that it is not pairing of the centromeres, but pairing and recombination along the arms of the homologs, that directs meiotic chromosome segregation.

scholarly journals Shugoshin is essential for meiotic prophase checkpoints in C. elegans

2018 ◽  
Author(s):  
Tisha Bohr ◽  
Christian R. Nelson ◽  
Stefani Giacopazzi ◽  
Piero Lamelza ◽  
Needhi Bhalla
Keyword(s):  
Sister Chromatid ◽  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Sister Chromatid Cohesion ◽  
Chromosomal Protein ◽  
Loss Of Function ◽  
Chromosome Architecture ◽  
C Elegans ◽  
Meiotic Chromosomes ◽  
Chromatid Cohesion

AbstractThe conserved factor Shugoshin is dispensable in C. elegans for the two-step loss of sister chromatid cohesion that directs the proper segregation of meiotic chromosomes. We show that the C. elegans ortholog of Shugoshin, SGO-1, is required for checkpoint activity in meiotic prophase. This role in checkpoint function is similar to that of the meiotic chromosomal protein, HTP-3. Null sgo-1 mutants exhibit additional phenotypes similar to that of a partial loss of function allele of HTP-3: premature synaptonemal complex disassembly, the activation of alternate DNA repair pathways and an inability to recruit a conserved effector of the DNA damage pathway, HUS-1. SGO-1 localizes to pre-meiotic nuclei, when HTP-3 is present but not yet loaded onto chromosome axes, suggesting an early role in regulating meiotic chromosome metabolism. We propose that SGO-1 acts during pre-meiotic replication to ensure fully functional meiotic chromosome architecture, rendering these chromosomes competent for checkpoint activity and normal progression of meiotic recombination. Given that most research on Shugoshin has been focused on its regulation of sister chromatid cohesion in meiosis, this novel role may be conserved but previously uncharacterized in other organisms. Further, our findings expand the repertoire of Shugoshin’s functions beyond coordinating regulatory activities at the centromere.

scholarly journals The Mnd1 Protein Forms a Complex with Hop2 To Promote Homologous Chromosome Pairing and Meiotic Double-Strand Break Repair

2002 ◽  
Vol 22 (9) ◽  
pp. 3078-3088 ◽  
Author(s):  
Hideo Tsubouchi ◽  
G. Shirleen Roeder
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Meiotic Chromosome ◽  
Strand Break ◽  
Rad51 Protein ◽  
Strand Breaks ◽  
Homolog Pairing ◽  
Cell Extracts ◽  
Homologous Chromosome Pairing ◽  
Multicopy Suppressors

ABSTRACT The hop2 mutant of Saccharomyces cerevisiae arrests in meiosis with extensive synaptonemal complex (SC) formation between nonhomologous chromosomes. A screen for multicopy suppressors of a hop2-ts allele identified the MND1 gene. The mnd1-null mutant arrests in meiotic prophase, with most double-strand breaks (DSBs) unrepaired. A low level of mature recombinants is produced, and the Rad51 protein accumulates at numerous foci along chromosomes. SC formation is incomplete, and homolog pairing is severely reduced. The Mnd1 protein localizes to chromatin throughout meiotic prophase, and this localization requires Hop2. Unlike recombination enzymes such as Rad51, Mnd1 localizes to chromosomes even in mutants that fail to initiate meiotic recombination. The Hop2 and Mnd1 proteins coimmunoprecipitate from meiotic cell extracts. These results suggest that Hop2 and Mnd1 work as a complex to promote meiotic chromosome pairing and DSB repair. The identification of Hop2 and Mnd1 homologs in other organisms suggests that the function of this complex is conserved among eukaryotes.

Sign in / Sign up

Export Citation Format

Share Document