scholarly journals The Formation of Bivalents and the Control of Plant Meiotic Recombination

2021 ◽  
Vol 12 ◽  
Author(s):  
Yared Gutiérrez Pinzón ◽  
José Kenyi González Kise ◽  
Patricia Rueda ◽  
Arnaud Ronceret
Keyword(s):  
Meiotic Recombination ◽  
Meiotic Division ◽  
Strand Break ◽  
Crop Plants ◽  
Meiotic Spindle ◽  
Axis Formation ◽  
Homologous Chromosomes ◽  
Bivalent Formation ◽  
Reductional Division ◽  
Made In

During the first meiotic division, the segregation of homologous chromosomes depends on the physical association of the recombined homologous DNA molecules. The physical tension due to the sites of crossing-overs (COs) is essential for the meiotic spindle to segregate the connected homologous chromosomes to the opposite poles of the cell. This equilibrated partition of homologous chromosomes allows the first meiotic reductional division. Thus, the segregation of homologous chromosomes is dependent on their recombination. In this review, we will detail the recent advances in the knowledge of the mechanisms of recombination and bivalent formation in plants. In plants, the absence of meiotic checkpoints allows observation of subsequent meiotic events in absence of meiotic recombination or defective meiotic chromosomal axis formation such as univalent formation instead of bivalents. Recent discoveries, mainly made in Arabidopsis, rice, and maize, have highlighted the link between the machinery of double-strand break (DSB) formation and elements of the chromosomal axis. We will also discuss the implications of what we know about the mechanisms regulating the number and spacing of COs (obligate CO, CO homeostasis, and interference) in model and crop plants.

scholarly journals Nonrandom Homolog Segregation at Meiosis I in Schizosaccharomyces pombe Mutants Lacking Recombination

Genetics ◽  
2003 ◽  
Vol 163 (3) ◽  
pp. 857-874 ◽  
Author(s):  
Luther Davis ◽  
Gerald R Smith
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Sister Chromatid ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
General Feature ◽  
Homologous Chromosomes ◽  
Chromatid Cohesion ◽  
Homozygous Diploid ◽  
Reductional Division ◽  
Meiosis I

Abstract Physical connection between homologous chromosomes is normally required for their proper segregation to opposite poles at the first meiotic division (MI). This connection is generally provided by the combination of reciprocal recombination and sister-chromatid cohesion. In the absence of meiotic recombination, homologs are predicted to segregate randomly at MI. Here we demonstrate that in rec12 mutants of the fission yeast Schizosaccharomyces pombe, which are devoid of meiosis-induced recombination, homologs segregate to opposite poles at MI 63% of the time. Residual, Rec12-independent recombination appears insufficient to account for the observed nonrandom homolog segregation. Dyad asci are frequently produced by rec12 mutants. More than half of these dyad asci contain two viable homozygous-diploid spores, the products of a single reductional division. This set of phenotypes is shared by other S. pombe mutants that lack meiotic recombination, suggesting that nonrandom MI segregation and dyad formation are a general feature of meiosis in the absence of recombination and are not peculiar to rec12 mutants. Rec8, a meiosis-specific sister-chromatid cohesin, is required for the segregation phenotypes displayed by rec12 mutants. We propose that S. pombe possesses a system independent of recombination that promotes homolog segregation and discuss possible mechanisms.

Making crossovers during meiosis

2005 ◽  
Vol 33 (6) ◽  
pp. 1451-1455 ◽  
Author(s):  
M.C. Whitby
Keyword(s):  
Genetic Variation ◽  
Homologous Recombination ◽  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
Meiotic Division ◽  
Holliday Junctions ◽  
Meiotic Spindle ◽  
Homologous Chromosomes ◽  
Dna Junctions

Homologous recombination (HR) is required to promote both correct chromosome segregation and genetic variation during meiosis. For this to be successful recombination intermediates must be resolved to generate reciprocal exchanges or ‘crossovers’ between the homologous chromosomes (homologues) during the first meiotic division. Crossover recombination promotes faithful chromosome segregation by establishing connections (chiasmata) between the homologues, which help guide their proper bipolar alignment on the meiotic spindle. Recent studies of meiotic recombination in both the budding and fission yeasts have established that there are at least two pathways for generating crossovers. One pathway involves the resolution of fully ligated four-way DNA junctions [HJs (Holliday junctions)] by an as yet unidentified endonuclease. The second pathway appears to involve the cleavage of the precursors of ligated HJs, namely displacement (D) loops and unligated/nicked HJs, by the Mus81-Eme1/Mms4 endonuclease.

scholarly journals Kinetochore Fibers Are Not Involved in the Formation of the First Meiotic Spindle in Mouse Oocytes, but Control the Exit from the First Meiotic M Phase

1999 ◽  
Vol 146 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Stéphane Brunet ◽  
Angélica Santa Maria ◽  
Philippe Guillaud ◽  
Denis Dujardin ◽  
Jacek Z. Kubiak ◽  
...  
Keyword(s):  
Polar Body ◽  
Meiotic Spindle ◽  
Homologous Chromosomes ◽  
Mouse Oocytes ◽  
Sister Chromatids ◽  
M Phase ◽  
Continuous Presence ◽  
Set Up ◽  
Polar Body Extrusion ◽  
Reductional Division

During meiosis, two successive divisions occur without any intermediate S phase to produce haploid gametes. The first meiotic division is unique in that homologous chromosomes are segregated while the cohesion between sister chromatids is maintained, resulting in a reductional division. Moreover, the duration of the first meiotic M phase is usually prolonged when compared with mitotic M phases lasting 8 h in mouse oocytes. We investigated the spindle assembly pathway and its role in the progression of the first meiotic M phase in mouse oocytes. During the first 4 h, a bipolar spindle forms and the chromosomes congress near the equatorial plane of the spindle without stable kinetochore– microtubule end interactions. This late prometaphase spindle is then maintained for 4 h with chromosomes oscillating in the central region of the spindle. The kinetochore–microtubule end interactions are set up at the end of the first meiotic M phase (8 h after entry into M phase). This event allows the final alignment of the chromosomes and exit from metaphase. The continuous presence of the prometaphase spindle is not required for progression of the first meiotic M phase. Finally, the ability of kinetochores to interact with microtubules is acquired at the end of the first meiotic M phase and determines the timing of polar body extrusion.

scholarly journals Genome Duplication Increases Meiotic Recombination Frequency: A Saccharomyces cerevisiae Model

2020 ◽  
Author(s):  
Ou Fang ◽  
Lin Wang ◽  
Yuxin Zhang ◽  
Jixuan Yang ◽  
Qin Tao ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Genome Stability ◽  
Genome Duplication ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Abiotic Factors ◽  
Strand Break ◽  
Homologous Chromosomes ◽  
Almost All

Abstract Genetic recombination characterized by reciprocal exchange of genes on paired homologous chromosomes is the most prominent event in meiosis of almost all sexually reproductive organisms. It contributes to genome stability by ensuring the balanced segregation of paired homologs in meiosis, and it is also the major driving factor in generating genetic variation for natural and artificial selection. Meiotic recombination is subjected to the control of a highly stringent and complex regulating process and meiotic recombination frequency (MRF) may be affected by biological and abiotic factors such as sex, gene density, nucleotide content, and chemical/temperature treatments, having motivated tremendous researches for artificially manipulating MRF. Whether genome polyploidization would lead to a significant change in MRF has attracted both historical and recent research interests; however, tackling this fundamental question is methodologically challenging due to the lack of appropriate methods for tetrasomic genetic analysis, thus has led to controversial conclusions in the literature. This article presents a comprehensive and rigorous survey of genome duplication-mediated change in MRF using Saccharomyces cerevisiae as a eukaryotic model. It demonstrates that genome duplication can lead to consistently significant increase in MRF and rate of crossovers across all 16 chromosomes of S. cerevisiae, including both cold and hot spots of MRF. This ploidy-driven change in MRF is associated with weakened recombination interference, enhanced double-strand break density, and loosened chromatin histone occupation. The study illuminates a significant evolutionary feature of genome duplication and opens an opportunity to accelerate response to artificial and natural selection through polyploidization.

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 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 DNA sequence differences are determinants of meiotic recombination outcome

2019 ◽  
Author(s):  
Simon D. Brown ◽  
Samantha J. Mpaulo ◽  
Mimi N. Asogwa ◽  
Marie Jézéquel ◽  
Matthew C. Whitby ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Relative Position ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Intragenic Recombination ◽  
Strong Impact ◽  
Dna Helicases ◽  
Homologous Chromosomes ◽  
Dna Double Strand Break ◽  
Sequence Polymorphisms

AbstractMeiotic recombination is essential for producing healthy gametes, and also generates genetic diversity. DNA double-strand break (DSB) formation is the initiating step of meiotic recombination, producing, among other outcomes, crossovers between homologous chromosomes (homologs), which provide physical links to guide accurate chromosome segregation. The parameters influencing DSB position and repair are thus crucial determinants of reproductive success and genetic diversity. Using Schizosaccharomyces pombe, we show that the distance between sequence polymorphisms across homologs has a strong impact on meiotic recombination rate. The closer the sequence polymorphisms are to each other across the homologs the fewer recombination events were observed. In the immediate vicinity of DSBs, sequence polymorphisms affect the frequency of intragenic recombination events (gene conversions). Additionally, and unexpectedly, the crossover rate of flanking markers tens of kilobases away from the sequence polymorphisms was affected by their relative position to each other amongst the progeny having undergone intragenic recombination. A major regulator of this distance-dependent effect is the MutSα-MutLα complex consisting of Msh2, Msh6, Mlh1, and Pms1. Additionally, the DNA helicases Rqh1 and Fml1 shape recombination frequency, although the effects seen here are largely independent of the relative position of the sequence polymorphisms.PreambleDue to a mistake during analysis of a batch of Sanger sequencing reactions for Supplementary Figure S1, we erroneously stated that we found evidence for intragenic crossovers. We now show that intragenic crossovers are less likely than we initially thought. We sincerely apologize for our mishap and any inconvenience it might have caused. However, this does not affect the main conclusions of our paper, just how some of our results are interpreted. This new manuscript version has been amended accordingly.

scholarly journals DNA sequence differences are determinants of meiotic recombination outcome

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Simon D. Brown ◽  
Samantha J. Mpaulo ◽  
Mimi N. Asogwa ◽  
Marie Jézéquel ◽  
Matthew C. Whitby ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Relative Position ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Intragenic Recombination ◽  
Strong Impact ◽  
Dna Helicases ◽  
Homologous Chromosomes ◽  
Dna Double Strand Break ◽  
Sequence Polymorphisms

Abstract Meiotic recombination is essential for producing healthy gametes, and also generates genetic diversity. DNA double-strand break (DSB) formation is the initiating step of meiotic recombination, producing, among other outcomes, crossovers between homologous chromosomes (homologs), which provide physical links to guide accurate chromosome segregation. The parameters influencing DSB position and repair are thus crucial determinants of reproductive success and genetic diversity. Using Schizosaccharomyces pombe, we show that the distance between sequence polymorphisms across homologs has a strong impact on meiotic recombination rate. The closer the sequence polymorphisms are to each other across the homologs the fewer recombination events were observed. In the immediate vicinity of DSBs, sequence polymorphisms affect the frequency of intragenic recombination events (gene conversions). Additionally, and unexpectedly, the crossover rate of flanking markers tens of kilobases away from the sequence polymorphisms was affected by their relative position to each other amongst the progeny having undergone intragenic recombination. A major regulator of this distance-dependent effect is the MutSα-MutLα complex consisting of Msh2, Msh6, Mlh1, and Pms1. Additionally, the DNA helicases Rqh1 and Fml1 shape recombination frequency, although the effects seen here are largely independent of the relative position of the sequence polymorphisms.

scholarly journals Crossover Interference in Saccharomyces cerevisiae Requires a TID1/RDH54- and DMC1-Dependent Pathway

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1273-1286 ◽  
Author(s):  
Miki Shinohara ◽  
Kazuko Sakai ◽  
Akira Shinohara ◽  
Douglas K Bishop
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Tetrad Analysis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Crossover Interference ◽  
Meiotic Progression ◽  
Invasion Stage ◽  
Strand Invasion ◽  
Dependent Pathway

Abstract Two RecA-like recombinases, Rad51 and Dmc1, function together during double-strand break (DSB)-mediated meiotic recombination to promote homologous strand invasion in the budding yeast Saccharomyces cerevisiae. Two partially redundant proteins, Rad54 and Tid1/Rdh54, act as recombinase accessory factors. Here, tetrad analysis shows that mutants lacking Tid1 form four-viable-spore tetrads with levels of interhomolog crossover (CO) and noncrossover recombination similar to, or slightly greater than, those in wild type. Importantly, tid1 mutants show a marked defect in crossover interference, a mechanism that distributes crossover events nonrandomly along chromosomes during meiosis. Previous work showed that dmc1Δ mutants are strongly defective in strand invasion and meiotic progression and that these defects can be partially suppressed by increasing the copy number of RAD54. Tetrad analysis is used to show that meiotic recombination in RAD54-suppressed dmc1Δ cells is similar to that in tid1; the frequency of COs and gene conversions is near normal, but crossover interference is defective. These results support the proposal that crossover interference acts at the strand invasion stage of recombination.

scholarly journals The Pif1 helicase is actively inhibited during meiotic recombination which restrains gene conversion tract length

2021 ◽  
Author(s):  
Dipti Vinayak Vernekar ◽  
Giordano Reginato ◽  
Céline Adam ◽  
Lepakshi Ranjha ◽  
Florent Dingli ◽  
...  
Keyword(s):  
Gene Conversion ◽  
Meiotic Recombination ◽  
Strand Break ◽  
Dna Helicase ◽  
Clamp Loader ◽  
Repair Synthesis ◽  
Dna Repair Synthesis ◽  
Gene Conversions

Abstract Meiotic recombination ensures proper chromosome segregation to form viable gametes and results in gene conversions events between homologs. Conversion tracts are shorter in meiosis than in mitotically dividing cells. This results at least in part from the binding of a complex, containing the Mer3 helicase and the MutLβ heterodimer, to meiotic recombination intermediates. The molecular actors inhibited by this complex are elusive. The Pif1 DNA helicase is known to stimulate DNA polymerase delta (Pol δ) -mediated DNA synthesis from D-loops, allowing long synthesis required for break-induced replication. We show that Pif1 is also recruited genome wide to meiotic DNA double-strand break (DSB) sites. We further show that Pif1, through its interaction with PCNA, is required for the long gene conversions observed in the absence of MutLβ recruitment to recombination sites. In vivo, Mer3 interacts with the PCNA clamp loader RFC, and in vitro, Mer3-MutLβ ensemble inhibits Pif1-stimulated D-loop extension by Pol δ and RFC-PCNA. Mechanistically, our results suggest that Mer3-MutLβ may compete with Pif1 for binding to RFC-PCNA. Taken together, our data show that Pif1’s activity that promotes meiotic DNA repair synthesis is restrained by the Mer3-MutLβ ensemble which in turn prevents long gene conversion tracts and possibly associated mutagenesis.

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