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Tan Y, Tan T, Zhang S, Li B, Chen B, Zhou X, Wang Y, Yang X, Zhai B, Huang Q, Zhang L, Wang S. Temperature regulates negative supercoils to modulate meiotic crossovers and chromosome organization. SCIENCE CHINA. LIFE SCIENCES 2024:10.1007/s11427-024-2671-1. [PMID: 39048717 DOI: 10.1007/s11427-024-2671-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
Crossover recombination is a hallmark of meiosis that holds the paternal and maternal chromosomes (homologs) together for their faithful segregation, while promoting genetic diversity of the progeny. The pattern of crossover is mainly controlled by the architecture of the meiotic chromosomes. Environmental factors, especially temperature, also play an important role in modulating crossovers. However, it is unclear how temperature affects crossovers. Here, we examined the distribution of budding yeast axis components (Red1, Hop1, and Rec8) and the crossover-associated Zip3 foci in detail at different temperatures, and found that both increased and decreased temperatures result in shorter meiotic chromosome axes and more crossovers. Further investigations showed that temperature changes coordinately enhanced the hyperabundant accumulation of Hop1 and Red1 on chromosomes and the number of Zip3 foci. Most importantly, temperature-induced changes in the distribution of axis proteins and Zip3 foci depend on changes in DNA negative supercoils. These results suggest that yeast meiosis senses temperature changes by increasing the level of negative supercoils to increase crossovers and modulate chromosome organization. These findings provide a new perspective on understanding the effect and mechanism of temperature on meiotic recombination and chromosome organization, with important implications for evolution and breeding.
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Affiliation(s)
- Yingjin Tan
- Advanced Medical Research Institute, Shandong University, Jinan, 250012, China
| | - Taicong Tan
- Advanced Medical Research Institute, Shandong University, Jinan, 250012, China
| | - Shuxian Zhang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Center for Reproductive Medicine, Institute of Women, Children and Reproductive Health, Shandong University, Jinan, 250012, China
| | - Bo Li
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China
| | - Beiyi Chen
- Advanced Medical Research Institute, Shandong University, Jinan, 250012, China
| | - Xu Zhou
- Advanced Medical Research Institute, Shandong University, Jinan, 250012, China
| | - Ying Wang
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250014, China
| | - Xiao Yang
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250014, China
| | - Binyuan Zhai
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250014, China
| | - Qilai Huang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China
| | - Liangran Zhang
- Advanced Medical Research Institute, Shandong University, Jinan, 250012, China.
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, 250014, China.
| | - Shunxin Wang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Center for Reproductive Medicine, Institute of Women, Children and Reproductive Health, Shandong University, Jinan, 250012, China.
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, China.
- Key Laboratory of Reproductive Endocrinology, Shandong University, Ministry of Education, Jinan, 250012, China.
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, China.
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, China.
- Shandong Key Laboratory of Reproductive Medicine, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250012, China.
- Research Unit of Gametogenesis and Health of ART-Offspring, Chinese Academy of Medical Sciences (No.2021RU001), Jinan, 250012, China.
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Aithal R, Nangalia K, Spirek M, Chen D, Klein F, Krejci L. Physical interaction with Spo11 mediates the localisation of Mre11 to chromatin in meiosis and promotes its nuclease activity. Nucleic Acids Res 2024; 52:4328-4343. [PMID: 38407383 PMCID: PMC11077076 DOI: 10.1093/nar/gkae111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 01/19/2024] [Accepted: 02/06/2024] [Indexed: 02/27/2024] Open
Abstract
Meiotic recombination is of central importance for the proper segregation of homologous chromosomes, but also for creating genetic diversity. It is initiated by the formation of double-strand breaks (DSBs) in DNA catalysed by evolutionarily conserved Spo11, together with additional protein partners. Difficulties in purifying the Spo11 protein have limited the characterization of its biochemical properties and of its interactions with other DSB proteins. In this study, we have purified fragments of Spo11 and show for the first time that Spo11 can physically interact with Mre11 and modulates its DNA binding, bridging, and nuclease activities. The interaction of Mre11 with Spo11 requires its far C-terminal region, which is in line with the severe meiotic phenotypes of various mre11 mutations located at the C-terminus. Moreover, calibrated ChIP for Mre11 shows that Spo11 promotes Mre11 recruitment to chromatin, independent of DSB formation. A mutant deficient in Spo11 interaction severely reduces the association of Mre11 with meiotic chromatin. Consistent with the reduction of Mre11 foci in this mutant, it strongly impedes DSB formation, leading to spore death. Our data provide evidence that physical interaction between Spo11 and Mre11, together with end-bridging, promote normal recruitment of Mre11 to hotspots and DSB formation.
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Affiliation(s)
- Rakesh Aithal
- National Centre for Biomolecular Research, Masaryk University, Brno, Czech Republic
- Department of Biology, Masaryk University, Brno, Czech Republic
| | - Kuldeep Nangalia
- Department of Chromosome Biology, Center for Molecular Biology, University of Vienna
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr.-Bohr-Gasse 9, 1030Vienna, Austria
| | - Mario Spirek
- Department of Biology, Masaryk University, Brno, Czech Republic
| | - Doris Chen
- Department of Chromosome Biology, Center for Molecular Biology, University of Vienna
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr.-Bohr-Gasse 9, 1030Vienna, Austria
| | - Franz Klein
- Department of Chromosome Biology, Center for Molecular Biology, University of Vienna
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Dr.-Bohr-Gasse 9, 1030Vienna, Austria
| | - Lumir Krejci
- National Centre for Biomolecular Research, Masaryk University, Brno, Czech Republic
- Department of Biology, Masaryk University, Brno, Czech Republic
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Diffusion and distal linkages govern interchromosomal dynamics during meiotic prophase. Proc Natl Acad Sci U S A 2022; 119:e2115883119. [PMID: 35302885 PMCID: PMC8944930 DOI: 10.1073/pnas.2115883119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceEssential for sexual reproduction, meiosis is a specialized cell division required for the production of haploid gametes. Critical to this process are the pairing, recombination, and segregation of homologous chromosomes (homologs). While pairing and recombination are linked, it is not known how many linkages are sufficient to hold homologs in proximity. Here, we reveal that random diffusion and the placement of a small number of linkages are sufficient to establish the apparent "pairing" of homologs. We also show that colocalization between any two loci is more dynamic than anticipated. Our study provides observations of live interchromosomal dynamics during meiosis and illustrates the power of combining single-cell measurements with theoretical polymer modeling.
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Loss, Gain, and Retention: Mechanisms Driving Late Prophase I Chromosome Remodeling for Accurate Meiotic Chromosome Segregation. Genes (Basel) 2022; 13:genes13030546. [PMID: 35328099 PMCID: PMC8949218 DOI: 10.3390/genes13030546] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/14/2022] [Accepted: 03/16/2022] [Indexed: 02/01/2023] Open
Abstract
To generate gametes, sexually reproducing organisms need to achieve a reduction in ploidy, via meiosis. Several mechanisms are set in place to ensure proper reductional chromosome segregation at the first meiotic division (MI), including chromosome remodeling during late prophase I. Chromosome remodeling after crossover formation involves changes in chromosome condensation and restructuring, resulting in a compact bivalent, with sister kinetochores oriented to opposite poles, whose structure is crucial for localized loss of cohesion and accurate chromosome segregation. Here, we review the general processes involved in late prophase I chromosome remodeling, their regulation, and the strategies devised by different organisms to produce bivalents with configurations that promote accurate segregation.
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Lenykó-Thegze A, Fábián A, Mihók E, Makai D, Cseh A, Sepsi A. Pericentromeric chromatin reorganisation follows the initiation of recombination and coincides with early events of synapsis in cereals. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1585-1602. [PMID: 34171148 DOI: 10.1111/tpj.15391] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/04/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
The reciprocal exchange of genetic information between homologous chromosomes during meiotic recombination is essential to secure balanced chromosome segregation and to promote genetic diversity. The chromosomal position and frequency of reciprocal genetic exchange shapes the efficiency of breeding programmes and influences crop improvement under a changing climate. In large genome cereals, such as wheat and barley, crossovers are consistently restricted to subtelomeric chromosomal regions, thus preventing favourable allele combinations being formed within a considerable proportion of the genome, including interstitial and pericentromeric chromatin. Understanding the key elements driving crossover designation is therefore essential to broaden the regions available for crossovers. Here, we followed early meiotic chromatin dynamism in cereals through the visualisation of a homologous barley chromosome arm pair stably transferred into the wheat genetic background. By capturing the dynamics of a single chromosome arm at the same time as detecting the undergoing events of meiotic recombination and synapsis, we showed that subtelomeric chromatin of homologues synchronously transitions to an open chromatin structure during recombination initiation. By contrast, pericentromeric and interstitial regions preserved their closed chromatin organisation and become unpackaged only later, concomitant with initiation of recombinatorial repair and the initial assembly of the synaptonemal complex. Our results raise the possibility that the closed pericentromeric chromatin structure in cereals may influence the fate decision during recombination initiation, as well as the spatial development of synapsis, and may also explain the suppression of crossover events in the proximity of the centromeres.
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Affiliation(s)
- Andrea Lenykó-Thegze
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, Brunszvik u. 2, Martonvásár, 2462, Hungary
| | - Attila Fábián
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, Brunszvik u. 2, Martonvásár, 2462, Hungary
| | - Edit Mihók
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, Brunszvik u. 2, Martonvásár, 2462, Hungary
| | - Diána Makai
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, Brunszvik u. 2, Martonvásár, 2462, Hungary
| | - András Cseh
- Department of Molecular Breeding, Eötvös Loránd Research Network, Centre for Agricultural Research, Brunszvik u. 2, Martonvásár, 2462, Hungary
| | - Adél Sepsi
- Department of Biological Resources, Eötvös Loránd Research Network, Centre for Agricultural Research, Brunszvik u. 2, Martonvásár, 2462, Hungary
- Department of Applied Biotechnology and Food Science (ABÉT), BME, Budapest University of Technology and Economics, Műegyetem rkp. 3-9, Budapest, 1111, Hungary
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6
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Sepsi A, Schwarzacher T. Chromosome-nuclear envelope tethering - a process that orchestrates homologue pairing during plant meiosis? J Cell Sci 2020; 133:jcs243667. [PMID: 32788229 PMCID: PMC7438012 DOI: 10.1242/jcs.243667] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
During prophase I of meiosis, homologous chromosomes pair, synapse and exchange their genetic material through reciprocal homologous recombination, a phenomenon essential for faithful chromosome segregation. Partial sequence identity between non-homologous and heterologous chromosomes can also lead to recombination (ectopic recombination), a highly deleterious process that rapidly compromises genome integrity. To avoid ectopic exchange, homology recognition must be extended from the narrow position of a crossover-competent double-strand break to the entire chromosome. Here, we review advances on chromosome behaviour during meiotic prophase I in higher plants, by integrating centromere- and telomere dynamics driven by cytoskeletal motor proteins, into the processes of homologue pairing, synapsis and recombination. Centromere-centromere associations and the gathering of telomeres at the onset of meiosis at opposite nuclear poles create a spatially organised and restricted nuclear state in which homologous DNA interactions are favoured but ectopic interactions also occur. The release and dispersion of centromeres from the nuclear periphery increases the motility of chromosome arms, allowing meiosis-specific movements that disrupt ectopic interactions. Subsequent expansion of interstitial synapsis from numerous homologous interactions further corrects ectopic interactions. Movement and organisation of chromosomes, thus, evolved to facilitate the pairing process, and can be modulated by distinct stages of chromatin associations at the nuclear envelope and their collective release.
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Affiliation(s)
- Adél Sepsi
- Department of Plant Cell Biology, Centre for Agricultural Research, 2462, Martonvásár, Brunszvik u. 2, Hungary
- BME Budapest University of Technology and Economics, Department of Applied Biotechnology and Food Science (ABÉT), 1111, Budapest, Mu˝ egyetem rkp. 3-9., Hungary
| | - Trude Schwarzacher
- University of Leicester, Department of Genetics and Genome Biology, University Road, Leicester LE1 7RH, UK
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization/Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
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Hong S, Joo JH, Yun H, Kleckner N, Kim KP. Recruitment of Rec8, Pds5 and Rad61/Wapl to meiotic homolog pairing, recombination, axis formation and S-phase. Nucleic Acids Res 2020; 47:11691-11708. [PMID: 31617566 PMCID: PMC7145551 DOI: 10.1093/nar/gkz903] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 12/14/2022] Open
Abstract
We have explored the meiotic roles of cohesin modulators Pds5 and Rad61/Wapl, in relation to one another, and to meiotic kleisin Rec8, for homolog pairing, all physically definable steps of recombination, prophase axis length and S-phase progression, in budding yeast. We show that Pds5 promotes early steps of recombination and thus homolog pairing, and also modulates axis length, with both effects independent of a sister chromatid. [Pds5+Rec8] promotes double-strand break formation, maintains homolog bias for crossover formation and promotes S-phase progression. Oppositely, the unique role of Rad61/Wapl is to promote non-crossover recombination by releasing [Pds5+Rec8]. For this effect, Rad61/Wapl probably acts to maintain homolog bias by preventing channeling into sister interactions. Mysteriously, each analyzed molecule has one role that involves neither of the other two. Overall, the presented findings suggest that Pds5's role in maintenance of sister chromatid cohesion during the mitotic prophase-analogous stage of G2/M is repurposed during meiosis prophase to promote interactions between homologs.
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Affiliation(s)
- Soogil Hong
- Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea
| | - Jeong H Joo
- Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea
| | - Hyeseon Yun
- Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
| | - Keun P Kim
- Department of Life Sciences, Chung-Ang University, Seoul 06974, Korea
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8
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Wang S, Liu Y, Shang Y, Zhai B, Yang X, Kleckner N, Zhang L. Crossover Interference, Crossover Maturation, and Human Aneuploidy. Bioessays 2019; 41:e1800221. [PMID: 31424607 PMCID: PMC6756933 DOI: 10.1002/bies.201800221] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 07/23/2019] [Indexed: 12/12/2022]
Abstract
A striking feature of human female sexual reproduction is the high level of gametes that exhibit an aberrant number of chromosomes (aneuploidy). A high baseline observed in women of prime reproductive age is followed by a dramatic increase in older women. Proper chromosome segregation requires one or more DNA crossovers (COs) between homologous maternal and paternal chromosomes, in combination with cohesion between sister chromatid arms. In human females, CO designations occur normally, according to the dictates of CO interference, giving early CO-fated intermediates. However, ≈25% of these intermediates fail to mature to final CO products. This effect explains the high baseline of aneuploidy and is predicted to synergize with age-dependent cohesion loss to explain the maternal age effect. Here, modern advances in the understanding of crossing over and CO interference are reviewed, the implications of human female CO maturation inefficiency are further discussed, and areas of interest for future studies are suggested.
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Affiliation(s)
- Shunxin Wang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Yanlei Liu
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Yongliang Shang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Binyuan Zhai
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Xiao Yang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Liangran Zhang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
- Advanced Medical Research Institute, Shandong University, Jinan, China
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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9
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High-Throughput Single-Cell Sequencing with Linear Amplification. Mol Cell 2019; 76:676-690.e10. [PMID: 31495564 DOI: 10.1016/j.molcel.2019.08.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 05/22/2019] [Accepted: 08/01/2019] [Indexed: 11/22/2022]
Abstract
Conventional methods for single-cell genome sequencing are limited with respect to uniformity and throughput. Here, we describe sci-L3, a single-cell sequencing method that combines combinatorial indexing (sci-) and linear (L) amplification. The sci-L3 method adopts a 3-level (3) indexing scheme that minimizes amplification biases while enabling exponential gains in throughput. We demonstrate the generalizability of sci-L3 with proof-of-concept demonstrations of single-cell whole-genome sequencing (sci-L3-WGS), targeted sequencing (sci-L3-target-seq), and a co-assay of the genome and transcriptome (sci-L3-RNA/DNA). We apply sci-L3-WGS to profile the genomes of >10,000 sperm and sperm precursors from F1 hybrid mice, mapping 86,786 crossovers and characterizing rare chromosome mis-segregation events in meiosis, including instances of whole-genome equational chromosome segregation. We anticipate that sci-L3 assays can be applied to fully characterize recombination landscapes, to couple CRISPR perturbations and measurements of genome stability, and to other goals requiring high-throughput, high-coverage single-cell sequencing.
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10
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Hong S, Joo JH, Yun H, Kim K. The nature of meiotic chromosome dynamics and recombination in budding yeast. J Microbiol 2019; 57:221-231. [PMID: 30671743 DOI: 10.1007/s12275-019-8541-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/24/2018] [Accepted: 10/26/2018] [Indexed: 12/28/2022]
Abstract
During meiosis, crossing over allows for the exchange of genes between homologous chromosomes, enabling their segregation and leading to genetic variation in the resulting gametes. Spo11, a topoisomerase-like protein expressed in eukaryotes, and diverse accessory factors induce programmed double-strand breaks (DSBs) to initiate meiotic recombination during the early phase of meiosis after DNA replication. DSBs are further repaired via meiosis-specific homologous recombination. Studies on budding yeast have provided insights into meiosis and genetic recombination and have improved our understanding of higher eukaryotic systems. Cohesin, a chromosome-associated multiprotein complex, mediates sister chromatid cohesion (SCC), and is conserved from yeast to humans. Diverse cohesin subunits in budding yeast have been identified in DNA metabolic pathways, such as DNA replication, chromosome segregation, recombination, DNA repair, and gene regulation. During cell cycle, SCC is established by multiple cohesin subunits, which physically bind sister chromatids together and modulate proteins that involve in the capturing and separation of sister chromatids. Cohesin components include at least four core subunits that establish and maintain SCC: two structural maintenance chromosome subunits (Smc1 and Smc3), an α-kleisin subunit (Mcd1/Scc1 during mitosis and Rec8 during meiosis), and Scc3/Irr1 (SA1 and SA2). In addition, the cohesin-associated factors Pds5 and Rad61 regulate structural modifications and cell cyclespecific dynamics of chromatin to ensure accurate chromosome segregation. In this review, we discuss SCC and the recombination pathway, as well as the relationship between the two processes in budding yeast, and we suggest a possible conserved mechanism for meiotic chromosome dynamics from yeast to humans.
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Affiliation(s)
- Soogil Hong
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Jeong Hwan Joo
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyeseon Yun
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Keunpil Kim
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea.
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11
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Ali EI, Loidl J, Howard-Till RA. A streamlined cohesin apparatus is sufficient for mitosis and meiosis in the protist Tetrahymena. Chromosoma 2018; 127:421-435. [PMID: 29948142 PMCID: PMC6208729 DOI: 10.1007/s00412-018-0673-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/18/2018] [Accepted: 05/28/2018] [Indexed: 02/03/2023]
Abstract
In order to understand its diverse functions, we have studied cohesin in the evolutionarily distant ciliate model organism Tetrahymena thermophila. In this binucleate cell, the heritable germline genome is maintained separately from the transcriptionally active somatic genome. In a previous study, we showed that a minimal cohesin complex in Tetrahymena consisted of homologs of Smc1, Smc3, and Rec8, which are present only in the germline nucleus, where they are needed for normal chromosome segregation as well as meiotic DNA repair. In this study, we confirm that a putative homolog of Scc3 is a member of this complex. In the absence of Scc3, Smc1 and Rec8 fail to localize to germline nuclei, Rec8 is hypo-phosphorylated, and cells show phenotypes similar to depletion of Smc1 and Rec8. We also identify a homolog of Scc2, which in other organisms is part of a heterodimeric complex (Scc2/Scc4) that helps load cohesin onto chromatin. In Tetrahymena, Scc2 interacts with Rec8 and Scc3, and its absence causes defects in mitotic and meiotic divisions. Scc2 is not required for chromosomal association of cohesin, but Rec8 is hypo-phosphorylated in its absence. Moreover, we did not identify a homolog of the cohesin loader Scc4, and no evidence was found of auxiliary factors, such as Eco1, Pds5, or WAPL. We propose that in Tetrahymena, a single, minimal cohesin complex performs all necessary functions for germline mitosis and meiosis, but is dispensable for transcription regulation and chromatin organization of the somatic genome.
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Affiliation(s)
- Emine I Ali
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Rachel A Howard-Till
- Department of Chromosome Biology, Vienna Biocenter, University of Vienna, Vienna, Austria.
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12
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Morgan CH, Zhang H, Bomblies K. Are the effects of elevated temperature on meiotic recombination and thermotolerance linked via the axis and synaptonemal complex? Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0470. [PMID: 29109229 PMCID: PMC5698628 DOI: 10.1098/rstb.2016.0470] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2017] [Indexed: 12/23/2022] Open
Abstract
Meiosis is unusual among cell divisions in shuffling genetic material by crossovers among homologous chromosomes and partitioning the genome into haploid gametes. Crossovers are critical for chromosome segregation in most eukaryotes, but are also an important factor in evolution, as they generate novel genetic combinations. The molecular mechanisms that underpin meiotic recombination and chromosome segregation are well conserved across kingdoms, but are also sensitive to perturbation by environment, especially temperature. Even subtle shifts in temperature can alter the number and placement of crossovers, while at greater extremes, structural failures can occur in the linear axis and synaptonemal complex structures which are essential for recombination and chromosome segregation. Understanding the effects of temperature on these processes is important for its implications in evolution and breeding, especially in the context of global warming. In this review, we first summarize the process of meiotic recombination and its reliance on axis and synaptonemal complex structures, and then discuss effects of temperature on these processes and structures. We hypothesize that some consistent effects of temperature on recombination and meiotic thermotolerance may commonly be two sides of the same coin, driven by effects of temperature on the folding or interaction of key meiotic proteins. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
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Affiliation(s)
| | - Huakun Zhang
- John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
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13
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Wang S, Hassold T, Hunt P, White MA, Zickler D, Kleckner N, Zhang L. Inefficient Crossover Maturation Underlies Elevated Aneuploidy in Human Female Meiosis. Cell 2017; 168:977-989.e17. [PMID: 28262352 DOI: 10.1016/j.cell.2017.02.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/15/2016] [Accepted: 01/31/2017] [Indexed: 01/20/2023]
Abstract
Meiosis is the cellular program that underlies gamete formation. For this program, crossovers between homologous chromosomes play an essential mechanical role to ensure regular segregation. We present a detailed study of crossover formation in human male and female meiosis, enabled by modeling analysis. Results suggest that recombination in the two sexes proceeds analogously and efficiently through most stages. However, specifically in female (but not male), ∼25% of the intermediates that should mature into crossover products actually fail to do so. Further, this "female-specific crossover maturation inefficiency" is inferred to make major contributions to the high level of chromosome mis-segregation and resultant aneuploidy that uniquely afflicts human female oocytes (e.g., giving Down syndrome). Additionally, crossover levels on different chromosomes in the same nucleus tend to co-vary, an effect attributable to global per-nucleus modulation of chromatin loop size. Maturation inefficiency could potentially reflect an evolutionary advantage of increased aneuploidy for human females.
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Affiliation(s)
- Shunxin Wang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Terry Hassold
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Patricia Hunt
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA
| | - Martin A White
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Denise Zickler
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Liangran Zhang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China.
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14
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Reichman R, Alleva B, Smolikove S. Prophase I: Preparing Chromosomes for Segregation in the Developing Oocyte. Results Probl Cell Differ 2017; 59:125-173. [PMID: 28247048 DOI: 10.1007/978-3-319-44820-6_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Formation of an oocyte involves a specialized cell division termed meiosis. In meiotic prophase I (the initial stage of meiosis), chromosomes undergo elaborate events to ensure the proper segregation of their chromosomes into gametes. These events include processes leading to the formation of a crossover that, along with sister chromatid cohesion, forms the physical link between homologous chromosomes. Crossovers are formed as an outcome of recombination. This process initiates with programmed double-strand breaks that are repaired through the use of homologous chromosomes as a repair template. The accurate repair to form crossovers takes place in the context of the synaptonemal complex, a protein complex that links homologous chromosomes in meiotic prophase I. To allow proper execution of meiotic prophase I events, signaling processes connect different steps in recombination and synapsis. The events occurring in meiotic prophase I are a prerequisite for proper chromosome segregation in the meiotic divisions. When these processes go awry, chromosomes missegregate. These meiotic errors are thought to increase with aging and may contribute to the increase in aneuploidy observed in advanced maternal age female oocytes.
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Affiliation(s)
- Rachel Reichman
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Benjamin Alleva
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA
| | - Sarit Smolikove
- Department of Biology, University of Iowa, Iowa City, IA, 52242, USA.
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15
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Bolaños-Villegas P, De K, Pradillo M, Liu D, Makaroff CA. In Favor of Establishment: Regulation of Chromatid Cohesion in Plants. FRONTIERS IN PLANT SCIENCE 2017; 8:846. [PMID: 28588601 PMCID: PMC5440745 DOI: 10.3389/fpls.2017.00846] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/05/2017] [Indexed: 05/07/2023]
Abstract
In eukaryotic organisms, the correct regulation of sister chromatid cohesion, whereby sister chromatids are paired and held together, is essential for accurate segregation of the sister chromatids and homologous chromosomes into daughter cells during mitosis and meiosis, respectively. Sister chromatid cohesion requires a cohesin complex comprised of structural maintenance of chromosome adenosine triphosphatases and accessory proteins that regulate the association of the complex with chromosomes or that are involved in the establishment or release of cohesion. The cohesin complex also plays important roles in the repair of DNA double-strand breaks, regulation of gene expression and chromosome condensation. In this review, we summarize progress in understanding cohesion dynamics in plants, with the aim of uncovering differences at specific stages. We also highlight dissimilarities between plants and other eukaryotes with respect to the key players involved in the achievement of cohesion, pointing out areas that require further study.
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Affiliation(s)
- Pablo Bolaños-Villegas
- Laboratory of Molecular and Cell Biology, Fabio Baudrit Agricultural Research Station, University of Costa RicaAlajuela, Costa Rica
- *Correspondence: Christopher A. Makaroff, Pablo Bolaños-Villegas,
| | - Kuntal De
- Department of Radiation Oncology, James Cancer Hospital and Comprehensive Cancer Center, The Ohio State University Wexner School of Medicine, ColumbusOH, United States
| | - Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad Complutense de MadridMadrid, Spain
| | - Desheng Liu
- Hughes Laboratories, Department of Chemistry and Biochemistry, Miami University, OxfordOH, United States
| | - Christopher A. Makaroff
- Hughes Laboratories, Department of Chemistry and Biochemistry, Miami University, OxfordOH, United States
- *Correspondence: Christopher A. Makaroff, Pablo Bolaños-Villegas,
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16
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Yoon SW, Lee MS, Xaver M, Zhang L, Hong SG, Kong YJ, Cho HR, Kleckner N, Kim KP. Meiotic prophase roles of Rec8 in crossover recombination and chromosome structure. Nucleic Acids Res 2016; 44:9296-9314. [PMID: 27484478 PMCID: PMC5100558 DOI: 10.1093/nar/gkw682] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 07/22/2016] [Indexed: 12/02/2022] Open
Abstract
Rec8 is a prominent component of the meiotic prophase chromosome axis that mediates sister chromatid cohesion, homologous recombination and chromosome synapsis. Here, we explore the prophase roles of Rec8. (i) During the meiotic divisions, Rec8 phosphorylation mediates its separase-mediated cleavage. We show here that such cleavage plays no detectable role for chromosomal events of prophase. (ii) We have analyzed in detail three rec8 phospho-mutants, with 6, 24 or 29 alanine substitutions. A distinct ‘separation of function’ phenotype is revealed. In the mutants, axis formation and recombination initiation are normal, as is non-crossover recombination; in contrast, crossover (CO)-related events are defective. Moreover, the severities of these defects increase coordinately with the number of substitution mutations, consistent with the possibility that global phosphorylation of Rec8 is important for these effects. (iii) We have analyzed the roles of three kinases that phosphorylate Rec8 during prophase. Timed inhibition of Dbf4-dependent Cdc7 kinase confers defects concordant with rec8 phospho-mutant phenotypes. Inhibition of Hrr25 or Cdc5/polo-like kinase does not. Our results suggest that Rec8's prophase function, independently of cohesin cleavage, contributes to CO-specific events in conjunction with the maintenance of homolog bias at the leptotene/zygotene transition of meiotic prophase.
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Affiliation(s)
- Sang-Wook Yoon
- Department of Life Science, Chung-Ang University, Seoul 156-756, Korea
| | - Min-Su Lee
- Department of Life Science, Chung-Ang University, Seoul 156-756, Korea
| | - Martin Xaver
- Max Perutz Laboratories, Chromosome Biology, University of Vienna, Vienna Biocenter, Vienna 1030, Austria
| | - Liangran Zhang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Soo-Gil Hong
- Department of Life Science, Chung-Ang University, Seoul 156-756, Korea
| | - Yoon-Ju Kong
- Department of Life Science, Chung-Ang University, Seoul 156-756, Korea
| | - Hong-Rae Cho
- Department of Life Science, Chung-Ang University, Seoul 156-756, Korea
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Keun P Kim
- Department of Life Science, Chung-Ang University, Seoul 156-756, Korea
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17
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A few of our favorite things: Pairing, the bouquet, crossover interference and evolution of meiosis. Semin Cell Dev Biol 2016; 54:135-48. [PMID: 26927691 DOI: 10.1016/j.semcdb.2016.02.024] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/22/2016] [Indexed: 12/20/2022]
Abstract
Meiosis presents many important mysteries that await elucidation. Here we discuss two such aspects. First, we consider how the current meiotic program might have evolved. We emphasize the central feature of this program: how homologous chromosomes find one another ("pair") so as to create the connections required for their regular segregation at Meiosis I. Points of emphasis include the facts that: (i) the classical "bouquet stage" is not required for initial homolog contacts in the current evolved meiotic program; and (ii) diverse observations point to commonality between molecules that mediate meiotic inter-homolog interactions and molecules that are integral to centromeres and/or to microtubule organizing centers (a.k.a. spindle pole bodies or centrosomes). Second, we provide an overview of the classical phenomenon of crossover (CO) interference in an effort to bridge the gap between description on the one hand versus logic and mechanism on the other.
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18
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Zickler D, Espagne E. Sordaria, a model system to uncover links between meiotic pairing and recombination. Semin Cell Dev Biol 2016; 54:149-57. [PMID: 26877138 DOI: 10.1016/j.semcdb.2016.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/08/2016] [Indexed: 11/20/2022]
Abstract
The mycelial fungus Sordaria macrospora was first used as experimental system for meiotic recombination. This review shows that it provides also a powerful cytological system for dissecting chromosome dynamics in wild-type and mutant meioses. Fundamental cytogenetic findings include: (1) the identification of presynaptic alignment as a key step in pairing of homologous chromosomes. (2) The discovery that biochemical complexes that mediate recombination at the DNA level concomitantly mediate pairing of homologs. (3) This pairing process involves not only resolution but also avoidance of chromosomal entanglements and the resolution system includes dissolution of constraining DNA recombination interactions, achieved by a unique role of Mlh1. (4) Discovery that the central components of the synaptonemal complex directly mediate the re-localization of the recombination proteins from on-axis to in-between homologue axis positions. (5) Identification of putative STUbL protein Hei10 as a structure-based signal transduction molecule that coordinates progression and differentiation of recombinational interactions at multiple stages. (6) Discovery that a single interference process mediates both nucleation of the SC and designation of crossover sites, thereby ensuring even spacing of both features. (7) Discovery of local modulation of sister-chromatid cohesion at sites of crossover recombination.
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Affiliation(s)
- Denise Zickler
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France.
| | - Eric Espagne
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette Cedex, France
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19
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Crawley O, Barroso C, Testori S, Ferrandiz N, Silva N, Castellano-Pozo M, Jaso-Tamame AL, Martinez-Perez E. Cohesin-interacting protein WAPL-1 regulates meiotic chromosome structure and cohesion by antagonizing specific cohesin complexes. eLife 2016; 5:e10851. [PMID: 26841696 PMCID: PMC4758955 DOI: 10.7554/elife.10851] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 12/23/2015] [Indexed: 12/21/2022] Open
Abstract
Wapl induces cohesin dissociation from DNA throughout the mitotic cell cycle, modulating sister chromatid cohesion and higher-order chromatin structure. Cohesin complexes containing meiosis-specific kleisin subunits govern most aspects of meiotic chromosome function, but whether Wapl regulates these complexes remains unknown. We show that during C. elegans oogenesis WAPL-1 antagonizes binding of cohesin containing COH-3/4 kleisins, but not REC-8, demonstrating that sensitivity to WAPL-1 is dictated by kleisin identity. By restricting the amount of chromosome-associated COH-3/4 cohesin, WAPL-1 controls chromosome structure throughout meiotic prophase. In the absence of REC-8, WAPL-1 inhibits COH-3/4-mediated cohesion, which requires crossover-fated events formed during meiotic recombination. Thus, WAPL-1 promotes functional specialization of meiotic cohesin: WAPL-1-sensitive COH-3/4 complexes modulate higher-order chromosome structure, while WAPL-1-refractory REC-8 complexes provide stable cohesion. Surprisingly, a WAPL-1-independent mechanism removes cohesin before metaphase I. Our studies provide insight into how meiosis-specific cohesin complexes are regulated to ensure formation of euploid gametes.
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Affiliation(s)
- Oliver Crawley
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Consuelo Barroso
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Sarah Testori
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Nuria Ferrandiz
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Nicola Silva
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Maikel Castellano-Pozo
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Angel Luis Jaso-Tamame
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Enrique Martinez-Perez
- Meiosis group, MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London, United Kingdom
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20
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Pradillo M, Knoll A, Oliver C, Varas J, Corredor E, Puchta H, Santos JL. Involvement of the Cohesin Cofactor PDS5 (SPO76) During Meiosis and DNA Repair in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2015; 6:1034. [PMID: 26648949 PMCID: PMC4664637 DOI: 10.3389/fpls.2015.01034] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/06/2015] [Indexed: 05/23/2023]
Abstract
Maintenance and precise regulation of sister chromatid cohesion is essential for faithful chromosome segregation during mitosis and meiosis. Cohesin cofactors contribute to cohesin dynamics and interact with cohesin complexes during cell cycle. One of these, PDS5, also known as SPO76, is essential during mitosis and meiosis in several organisms and also plays a role in DNA repair. In yeast, the complex Wapl-Pds5 controls cohesion maintenance and colocalizes with cohesin complexes into chromosomes. In Arabidopsis, AtWAPL proteins are essential during meiosis, however, the role of AtPDS5 remains to be ascertained. Here we have isolated mutants for each of the five AtPDS5 genes (A-E) and obtained, after different crosses between them, double, triple, and even quadruple mutants (Atpds5a Atpds5b Atpds5c Atpds5e). Depletion of AtPDS5 proteins has a weak impact on meiosis, but leads to severe effects on development, fertility, somatic homologous recombination (HR) and DNA repair. Furthermore, this cohesin cofactor could be important for the function of the AtSMC5/AtSMC6 complex. Contrarily to its function in other species, our results suggest that AtPDS5 is dispensable during the meiotic division of Arabidopsis, although it plays an important role in DNA repair by HR.
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Affiliation(s)
- Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Alexander Knoll
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Cecilia Oliver
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Javier Varas
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Eduardo Corredor
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
| | - Holger Puchta
- Botanical Institute II, Karlsruhe Institute of TechnologyKarlsruhe, Germany
| | - Juan L. Santos
- Departamento de Genética, Facultad de Biología, Universidad ComplutenseMadrid, Spain
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Abstract
The study of homologous recombination has its historical roots in meiosis. In this context, recombination occurs as a programmed event that culminates in the formation of crossovers, which are essential for accurate chromosome segregation and create new combinations of parental alleles. Thus, meiotic recombination underlies both the independent assortment of parental chromosomes and genetic linkage. This review highlights the features of meiotic recombination that distinguish it from recombinational repair in somatic cells, and how the molecular processes of meiotic recombination are embedded and interdependent with the chromosome structures that characterize meiotic prophase. A more in-depth review presents our understanding of how crossover and noncrossover pathways of meiotic recombination are differentiated and regulated. The final section of this review summarizes the studies that have defined defective recombination as a leading cause of pregnancy loss and congenital disease in humans.
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Affiliation(s)
- Neil Hunter
- Howard Hughes Medical Institute, Department of Microbiology & Molecular Genetics, Department of Molecular & Cellular Biology, Department of Cell Biology & Human Anatomy, University of California Davis, Davis, California 95616
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22
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Meiotic cohesin-based chromosome structure is essential for homologous chromosome pairing in Schizosaccharomyces pombe. Chromosoma 2015; 125:205-14. [PMID: 26511279 PMCID: PMC4830870 DOI: 10.1007/s00412-015-0551-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 10/07/2015] [Accepted: 10/09/2015] [Indexed: 11/30/2022]
Abstract
Chromosome structure is dramatically altered upon entering meiosis to establish chromosomal architectures necessary for the successful progression of meiosis-specific events. An early meiotic event involves the replacement of the non-SMC mitotic cohesins with their meiotic equivalents in most part of the chromosome, forming an axis on meiotic chromosomes. We previously demonstrated that the meiotic cohesin complex is required for chromosome compaction during meiotic prophase in the fission yeast Schizosaccharomyces pombe. These studies revealed that chromosomes are elongated in the absence of the meiotic cohesin subunit Rec8 and shortened in the absence of the cohesin-associated protein Pds5. In this study, using super-resolution structured illumination microscopy, we found that Rec8 forms a linear axis on chromosomes, which is required for the organized axial structure of chromatin during meiotic prophase. In the absence of Pds5, the Rec8 axis is shortened whereas chromosomes are widened. In rec8 or pds5 mutants, the frequency of homologous chromosome pairing is reduced. Thus, Rec8 and Pds5 play an essential role in building a platform to support the chromosome architecture necessary for the spatial alignment of homologous chromosomes.
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Lambing C, Osman K, Nuntasoontorn K, West A, Higgins JD, Copenhaver GP, Yang J, Armstrong SJ, Mechtler K, Roitinger E, Franklin FCH. Arabidopsis PCH2 Mediates Meiotic Chromosome Remodeling and Maturation of Crossovers. PLoS Genet 2015; 11:e1005372. [PMID: 26182244 PMCID: PMC4504720 DOI: 10.1371/journal.pgen.1005372] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 06/19/2015] [Indexed: 11/30/2022] Open
Abstract
Meiotic chromosomes are organized into linear looped chromatin arrays by a protein axis localized along the loop-bases. Programmed remodelling of the axis occurs during prophase I of meiosis. Structured illumination microscopy (SIM) has revealed dynamic changes in the chromosome axis in Arabidopsis thaliana and Brassica oleracea. We show that the axis associated protein ASY1 is depleted during zygotene concomitant with synaptonemal complex (SC) formation. Study of an Atpch2 mutant demonstrates this requires the conserved AAA+ ATPase, PCH2, which localizes to the sites of axis remodelling. Loss of PCH2 leads to a failure to deplete ASY1 from the axes and compromizes SC polymerisation. Immunolocalization of recombination proteins in Atpch2 indicates that recombination initiation and CO designation during early prophase I occur normally. Evidence suggests that CO interference is initially functional in the mutant but there is a defect in CO maturation following designation. This leads to a reduction in COs and a failure to form COs between some homologous chromosome pairs leading to univalent chromosomes at metaphase I. Genetic analysis reveals that CO distribution is also affected in some chromosome regions. Together these data indicate that the axis remodelling defect in Atpch2 disrupts normal patterned formation of COs. In the reproductive cells of many eukaryotes, a process called meiosis generates haploid gametes. During meiosis, homologous parental chromosomes (homologs) recombine forming crossovers (CO) that provide genetic variation. CO formation generates physical links called chiasmata, which are essential for accurate homolog segregation. CO control designates a sub-set of recombination precursors that will mature to form at least one chiasma between each homolog pair. Recombination is accompanied by extensive chromosome reorganization. Formation of a proteinaceous axis organizes the pairs of sister chromatids of each homolog into conjoined linear looped chromatin arrays. Pairs of homologs then align and synapse becoming closely associated along their length by a protein structure, the synaptonemal complex (SC). The SC is disassembled at the end of prophase I and recombination is completed. We have investigated the link between recombination and chromosome remodelling by analysing the role of a protein, PCH2, which we show is required for remodelling of the chromosome axis during SC formation. In wild type, immunolocalization reveals depletion of the axis-associated signal of the axis component, ASY1, along synapsed regions of the chromosomes. In the absence of PCH2, the ASY1 signal is not depleted from the chromosome axis and the SC does not form normally. Although this defect in chromosome remodelling has no obvious effect on CO designation, CO maturation is perturbed such that the formation of at least one CO per homolog pair no longer occurs.
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Affiliation(s)
- Christophe Lambing
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Kim Osman
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Komsun Nuntasoontorn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Allan West
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - James D. Higgins
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Gregory P. Copenhaver
- Department of Biology and Carolina Center for Genome Scientists, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Jianhua Yang
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Susan J. Armstrong
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | | | | | - F. Chris H. Franklin
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
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24
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Zickler D, Kleckner N. Recombination, Pairing, and Synapsis of Homologs during Meiosis. Cold Spring Harb Perspect Biol 2015; 7:cshperspect.a016626. [PMID: 25986558 DOI: 10.1101/cshperspect.a016626] [Citation(s) in RCA: 500] [Impact Index Per Article: 55.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Recombination is a prominent feature of meiosis in which it plays an important role in increasing genetic diversity during inheritance. Additionally, in most organisms, recombination also plays mechanical roles in chromosomal processes, most notably to mediate pairing of homologous chromosomes during prophase and, ultimately, to ensure regular segregation of homologous chromosomes when they separate at the first meiotic division. Recombinational interactions are also subject to important spatial patterning at both early and late stages. Recombination-mediated processes occur in physical and functional linkage with meiotic axial chromosome structure, with interplay in both directions, before, during, and after formation and dissolution of the synaptonemal complex (SC), a highly conserved meiosis-specific structure that links homolog axes along their lengths. These diverse processes also are integrated with recombination-independent interactions between homologous chromosomes, nonhomology-based chromosome couplings/clusterings, and diverse types of chromosome movement. This review provides an overview of these diverse processes and their interrelationships.
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Affiliation(s)
- Denise Zickler
- Institut de Génétique et Microbiologie, UMR 8621, Université Paris-Sud, 91405 Orsay, France
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
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25
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Kołowerzo-Lubnau A, Niedojadło J, Świdziński M, Bednarska-Kozakiewicz E, Smoliński DJ. Transcriptional activity in diplotene larch microsporocytes, with emphasis on the diffuse stage. PLoS One 2015; 10:e0117337. [PMID: 25671569 PMCID: PMC4324999 DOI: 10.1371/journal.pone.0117337] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 12/22/2014] [Indexed: 12/22/2022] Open
Abstract
Manuscript provides insights into the biology of long-lived plants, different from Arabidopsis, tomato or grass species that are widely studied. In the European larch the diplotene stage lasts approximately 5 months and it is possible to divide it into several substages and to observe each of them in details. The diplotene stage is a period of intensive microsporocyte growth associated with the synthesis and accumulation of different RNA and proteins. Larch microsporocytes display changes in chromatin morphology during this stage, alternating between 4 short stages of chromatin condensation (contraction) and 5 longer diffusion (relaxation) stages. The occurrence of a diplotene diffusion stage has been observed in many plant species. Interestingly, they have also been observed during spermiogenesis and oogenesis in animals. The aim of this study was to examine whether chromatin relaxation during the diplotene is accompanied by the synthesis and maturation of mRNA. The results reveal a correlation between the diffusion and chromatin decondensation, transcriptional activity. We also found decreasing amount of poly(A) mRNA synthesis in the consecutive diffusion stages. During the early diffusion stages, mRNA is intensively synthesized. In the nuclei large amounts of RNA polymerase II, and high levels of snRNPs were observed. In the late diffusion stages, the synthesized mRNA is not directly subjected to translation but it is stored in the nucleus, and later transported to the cytoplasm and translated. In the last diffusion stage, the level of poly(A) RNA is low, but that of splicing factors is still high. It appears that the mRNA synthesized in early stages is used during the diplotene stage and is not transmitted to dyad and tetrads. In contrast, splicing factors accumulate and are most likely transmitted to the dyad and tetrads, where they are used after the resumption of intense transcription. Similar meiotic process were observed during oogenesis in animals. This indicates the existence of an evolutionarily conserved mechanism of chromatin-based regulation of gene expression during meiotic prophase I.
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Affiliation(s)
- Agnieszka Kołowerzo-Lubnau
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Toruń, Poland
- * E-mail: (AKL); (DJS)
| | - Janusz Niedojadło
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Michał Świdziński
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Elżbieta Bednarska-Kozakiewicz
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
| | - Dariusz J. Smoliński
- Department of Cell Biology, Faculty of Biology and Environment Protection, Nicolaus Copernicus University, Toruń, Poland
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Toruń, Poland
- * E-mail: (AKL); (DJS)
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Absence of SUN-domain protein Slp1 blocks karyogamy and switches meiotic recombination and synapsis from homologs to sister chromatids. Proc Natl Acad Sci U S A 2014; 111:E4015-23. [PMID: 25210014 DOI: 10.1073/pnas.1415758111] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Karyogamy, the process of nuclear fusion is required for two haploid gamete nuclei to form a zygote. Also, in haplobiontic organisms, karyogamy is required to produce the diploid nucleus/cell that then enters meiosis. We identify sun like protein 1 (Slp1), member of the mid-Sad1p, UNC-84-domain ubiquitous family, as essential for karyogamy in the filamentous fungus Sordaria macrospora, thus uncovering a new function for this protein family. Slp1 is required at the last step, nuclear fusion, not for earlier events including nuclear movements, recognition, and juxtaposition. Correspondingly, like other family members, Slp1 localizes to the endoplasmic reticulum and also to its extensions comprising the nuclear envelope. Remarkably, despite the absence of nuclear fusion in the slp1 null mutant, meiosis proceeds efficiently in the two haploid "twin" nuclei, by the same program and timing as in diploid nuclei with a single dramatic exception: the normal prophase program of recombination and synapsis between homologous chromosomes, including loading of recombination and synaptonemal complex proteins, occurs instead between sister chromatids. Moreover, the numbers of recombination-initiating double-strand breaks (DSBs) and ensuing recombinational interactions, including foci of the essential crossover factor Homo sapiens enhancer of invasion 10 (Hei10), occur at half the diploid level in each haploid nucleus, implying per-chromosome specification of DSB formation. Further, the distribution of Hei10 foci shows interference like in diploid meiosis. Centromere and spindle dynamics, however, still occur in the diploid mode during the two meiotic divisions. These observations imply that the prophase program senses absence of karyogamy and/or absence of a homolog partner and adjusts the interchromosomal interaction program accordingly.
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Efficient detection of unpaired DNA requires a member of the rad54-like family of homologous recombination proteins. Genetics 2014; 198:895-904. [PMID: 25146971 DOI: 10.1534/genetics.114.168187] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Meiotic silencing by unpaired DNA (MSUD) is a process that detects unpaired regions between homologous chromosomes and silences them for the duration of sexual development. While the phenomenon of MSUD is well recognized, the process that detects unpaired DNA is poorly understood. In this report, we provide two lines of evidence linking unpaired DNA detection to a physical search for DNA homology. First, we have found that a putative SNF2-family protein (SAD-6) is required for efficient MSUD in Neurospora crassa. SAD-6 is closely related to Rad54, a protein known to facilitate key steps in the repair of double-strand breaks by homologous recombination. Second, we have successfully masked unpaired DNA by placing identical transgenes at slightly different locations on homologous chromosomes. This masking falls apart when the distance between the transgenes is increased. We propose a model where unpaired DNA detection during MSUD is achieved through a spatially constrained search for DNA homology. The identity of SAD-6 as a Rad54 paralog suggests that this process may be similar to the searching mechanism used during homologous recombination.
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Jahns MT, Vezon D, Chambon A, Pereira L, Falque M, Martin OC, Chelysheva L, Grelon M. Crossover localisation is regulated by the neddylation posttranslational regulatory pathway. PLoS Biol 2014; 12:e1001930. [PMID: 25116939 PMCID: PMC4130666 DOI: 10.1371/journal.pbio.1001930] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/03/2014] [Indexed: 12/21/2022] Open
Abstract
A genetic study finds the neddylation pathway (known to-date for post-translational protein modification) is involved in regulating crossover localization but not crossover number during meiosis in Arabidopsis. Crossovers (COs) are at the origin of genetic variability, occurring across successive generations, and they are also essential for the correct segregation of chromosomes during meiosis. Their number and position are precisely controlled, however the mechanisms underlying these controls are poorly understood. Neddylation/rubylation is a regulatory pathway of posttranslational protein modification that is required for numerous cellular processes in eukaryotes, but has not yet been linked to homologous recombination. In a screen for meiotic recombination-defective mutants, we identified several axr1 alleles, disrupting the gene encoding the E1 enzyme of the neddylation complex in Arabidopsis. Using genetic and cytological approaches we found that axr1 mutants are characterised by a shortage in bivalent formation correlated with strong synapsis defects. We determined that the bivalent shortage in axr1 is not due to a general decrease in CO formation but rather due to a mislocalisation of class I COs. In axr1, as in wild type, COs are still under the control of the ZMM group of proteins. However, in contrast to wild type, they tend to cluster together and no longer follow the obligatory CO rule. Lastly, we showed that this deregulation of CO localisation is likely to be mediated by the activity of a cullin 4 RING ligase, known to be involved in DNA damage sensing during somatic DNA repair and mouse spermatogenesis. In conclusion, we provide evidence that the neddylation/rubylation pathway of protein modification is a key regulator of meiotic recombination. We propose that rather than regulating the number of recombination events, this pathway regulates their localisation, through the activation of cullin 4 RING ligase complexes. Possible targets for these ligases are discussed. During meiosis, two successive chromosomal divisions follow a single S phase, resulting in the formation of four haploid cells, each with half of the parental genetic material. This reduction in chromosome number occurs during the first meiotic division, when homologous chromosomes (paternal and maternal) are separated from each other. For this to happen, homologous chromosomes associate in structures called bivalents, where each chromosome is linked to its homologue by a point of contact known as chiasmata. These chiasmata reflect the formation of crossovers (COs), one of the manifestations of the exchange of genetic material occurring during homologous recombination. CO number varies little at around two per chromosome pair, and they tend to be evenly spaced on chromosomes. Thus, CO number and distribution are very tightly controlled. However, the mechanisms underlying these controls are very poorly understood. In this study, we identified a regulatory pathway of meiotic recombination. We show that this pathway does not regulate the amount of recombination events per se, but instead controls their localisation, as when it is defective, CO events cluster together in a few regions of the genome, leading to bivalent shortage and progeny aneuploidy with incorrect numbers of chromosomes. This regulatory pathway is a posttranslational protein modification system called neddylation (or rubylation in plants), known to be required for numerous cellular processes in eukaryotes. We identify an enzyme of the neddylation complex as a major regulator of meiotic recombination in Arabidopsis and show that this process may be also conserved in mammals.
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Affiliation(s)
- Marina Tagliaro Jahns
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
| | - Daniel Vezon
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
| | - Aurélie Chambon
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
| | - Lucie Pereira
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
| | - Matthieu Falque
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche de Génétique Végétale, Université Paris-Sud, Gif-sur-Yvette, France
| | - Olivier C. Martin
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche de Génétique Végétale, Université Paris-Sud, Gif-sur-Yvette, France
| | - Liudmila Chelysheva
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
| | - Mathilde Grelon
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, Versailles, France
- * E-mail:
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Lo YH, Chuang CN, Wang TF. Pch2 prevents Mec1/Tel1-mediated Hop1 phosphorylation occurring independently of Red1 in budding yeast meiosis. PLoS One 2014; 9:e85687. [PMID: 24465650 PMCID: PMC3897485 DOI: 10.1371/journal.pone.0085687] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 12/05/2013] [Indexed: 11/18/2022] Open
Abstract
A prominent feature of meiosis in most sexually reproducing organisms is interhomolog recombination whereby a significant fraction of the programmed meiotic double-strand breaks are repaired using intact homologous non-sister chromatids rather than sister chromatids. Budding yeast DNA damage checkpoint kinases Mec1 and Tel1 act together with the axial element protein Red1 to promote interhomolog recombination by phosphorylating another axial element protein Hop1. Mec1 and Tel1 also phosphorylate γH2A and the synaptonemal complex protein Zip1 independently of Red1 to facilitate premeiotic DNA replication and to destabilize homology-independent centromere pairing, respectively. It has been unclear why Hop1 phosphorylation is Red1-dependent. Here, we report that the pachytene checkpoint protein 2 (Pch2) specifically prevents Red1-independent Hop1 phosphorylation. Our findings reveal a new function for Pch2 in linking two axial element proteins Red1 and Hop1 thus coordinating their effects in meiotic recombination and the checkpoint network.
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Affiliation(s)
- Yu-Hui Lo
- Institute of Life Science, National Defense Medical Center, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Chi-Ning Chuang
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Ting-Fang Wang
- Institute of Life Science, National Defense Medical Center, Taipei, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- * E-mail:
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30
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Meiotic recombination in Arabidopsis is catalysed by DMC1, with RAD51 playing a supporting role. PLoS Genet 2013; 9:e1003787. [PMID: 24086145 PMCID: PMC3784562 DOI: 10.1371/journal.pgen.1003787] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/26/2013] [Indexed: 11/29/2022] Open
Abstract
Recombination establishes the chiasmata that physically link pairs of homologous chromosomes in meiosis, ensuring their balanced segregation at the first meiotic division and generating genetic variation. The visible manifestation of genetic crossing-overs, chiasmata are the result of an intricate and tightly regulated process involving induction of DNA double-strand breaks and their repair through invasion of a homologous template DNA duplex, catalysed by RAD51 and DMC1 in most eukaryotes. We describe here a RAD51-GFP fusion protein that retains the ability to assemble at DNA breaks but has lost its DNA break repair capacity. This protein fully complements the meiotic chromosomal fragmentation and sterility of Arabidopsis rad51, but not rad51 dmc1 mutants. Even though DMC1 is the only active meiotic strand transfer protein in the absence of RAD51 catalytic activity, no effect on genetic map distance was observed in complemented rad51 plants. The presence of inactive RAD51 nucleofilaments is thus able to fully support meiotic DSB repair and normal levels of crossing-over by DMC1. Our data demonstrate that RAD51 plays a supporting role for DMC1 in meiotic recombination in the flowering plant, Arabidopsis. Recombination ensures coordinated disjunction of pairs of homologous chromosomes and generates genetic exchanges in meiosis and, with some exceptions, involves the co-operation of the RAD51 and DMC1 strand-exchange proteins. We describe here a RAD51-GFP fusion protein that has lost its DNA break repair capacity but retains the ability to assemble at DNA breaks in the plant, Arabidopsis - fully complementing the meiotic chromosomal fragmentation and sterility of rad51 mutants, and this depends upon DMC1. No effect on genetic map distance was observed in complemented rad51 plants even though DMC1 is the only active strand transfer protein. The inactive RAD51 nucleofilaments are thus able to fully support meiotic DSB repair and normal levels of crossing-over by DMC1 in Arabidopsis. The RAD51-GFP protein confers a dominant-negative inhibition of RAD51-dependent mitotic recombination, while remaining fully fertile - a novel and valuable tool for research in this domain. These phenotypes are equivalent to those of the recently reported yeast rad51-II3A mutant, (Cloud et al. 2012), carrying the implication of their probable generality in other eukaryotes and extending them to a species with a very different relation between numbers of meiotic DNA double-strand breaks and crossing-overs (∼2 DSB/CO in yeast; ∼25–30 DSB/CO in Arabidopsis; ∼15 DSB/CO in mice).
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Peraza-Reyes L, Berteaux-Lecellier V. Peroxisomes and sexual development in fungi. Front Physiol 2013; 4:244. [PMID: 24046747 PMCID: PMC3764329 DOI: 10.3389/fphys.2013.00244] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 08/19/2013] [Indexed: 11/13/2022] Open
Abstract
Peroxisomes are versatile and dynamic organelles that are essential for the development of most eukaryotic organisms. In fungi, many developmental processes, such as sexual development, require the activity of peroxisomes. Sexual reproduction in fungi involves the formation of meiotic-derived sexual spores, often takes place inside multicellular fruiting bodies and requires precise coordination between the differentiation of multiple cell types and the progression of karyogamy and meiosis. Different peroxisomal functions contribute to the orchestration of this complex developmental process. Peroxisomes are required to sustain the formation of fruiting bodies and the maturation and germination of sexual spores. They facilitate the mobilization of reserve compounds via fatty acid β-oxidation and the glyoxylate cycle, allowing the generation of energy and biosynthetic precursors. Additionally, peroxisomes are implicated in the progression of meiotic development. During meiotic development in Podospora anserina, there is a precise modulation of peroxisome assembly and dynamics. This modulation includes changes in peroxisome size, number and localization, and involves a differential activity of the protein-machinery that drives the import of proteins into peroxisomes. Furthermore, karyogamy, entry into meiosis and sorting of meiotic-derived nuclei into sexual spores all require the activity of peroxisomes. These processes rely on different peroxisomal functions and likely depend on different pathways for peroxisome assembly. Indeed, emerging studies support the existence of distinct import channels for peroxisomal proteins that contribute to different developmental stages.
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Affiliation(s)
- Leonardo Peraza-Reyes
- CNRS, Institut de Génétique et Microbiologie, University Paris-Sud, UMR8621 Orsay, France
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32
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Abstract
Sister chromatid cohesion depends on cohesin, a tripartite complex that forms ring structures to hold sister chromatids together in mitosis and meiosis. Meiocytes feature a multiplicity of distinct cohesin proteins and complexes, some meiosis specific, which serve additional functions such as supporting synapsis of two pairs of sister chromatids and determining the loop-axis architecture of prophase I chromosomes. Despite considerable new insights gained in the past few years into the localization and function of some cohesin proteins, and the recent identification of yet another meiosis-specific cohesin subunit, a plethora of open questions remains, which concern not only fundamental germ cell biology but also the consequences of cohesin impairment for human reproductive health.
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Affiliation(s)
- François McNicoll
- Institute of Physiological Chemistry, Medical Faculty Carl Gustav Carus, Dresden University of Technology, Dresden, Germany
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33
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Abstract
The cohesin complex, named for its key role in sister chromatid cohesion, also plays critical roles in gene regulation and DNA repair. It performs all three functions in single cell eukaryotes such as yeasts, and in higher organisms such as man. Minor disruption of cohesin function has significant consequences for human development, even in the absence of measurable effects on chromatid cohesion or chromosome segregation. Here we survey the roles of cohesin in gene regulation and DNA repair, and how these functions vary from yeast to man.
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Affiliation(s)
- Dale Dorsett
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA.
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34
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The spread of a transposon insertion in Rec8 is associated with obligate asexuality in Daphnia. Proc Natl Acad Sci U S A 2012; 109:858-63. [PMID: 22215604 DOI: 10.1073/pnas.1119667109] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Although transitions from sexual to asexual reproduction are thought to have important evolutionary consequences, little is known about the mechanistic underpinnings of these changes. The cyclical parthenogen Daphnia pulex is a powerful model in which to address these issues because female-limited meiosis suppression can be transmitted to sexual individuals via males, providing the opportunity for genetic dissection of the trait. A previous study identified genomic regions differentiating obligately asexual females from their sexual counterparts, and a candidate gene within one such region, encoding the meiotic cohesin Rec8, is the subject of this investigation. The D. pulex genome contains three Rec8 loci, all of which are quite polymorphic. However, at one of the loci, all obligately asexual clones carry an allele containing an identical upstream insertion of a transposable element as well as a frameshift mutation, both of which are completely absent from sexual lineages. The low level of variation within the insertion allele across all asexual lineages suggests that this element may be in the process of spreading through the species, and abrogation or modification of Rec8 function is possibly responsible for converting meiotically reproducing lineages into obligate asexuals.
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35
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Lightfoot J, Testori S, Barroso C, Martinez-Perez E. Loading of meiotic cohesin by SCC-2 is required for early processing of DSBs and for the DNA damage checkpoint. Curr Biol 2011; 21:1421-30. [PMID: 21856158 DOI: 10.1016/j.cub.2011.07.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 06/21/2011] [Accepted: 07/07/2011] [Indexed: 12/20/2022]
Abstract
BACKGROUND Chromosome segregation and the repair of DNA double-strand breaks (DSBs) by homologous recombination require cohesin, the protein complex that mediates sister chromatid cohesion (SCC). In addition, cohesin is also required for the integrity of DNA damage checkpoints in somatic cells, where cohesin loading depends on a conserved complex containing the Scc2/Nipbl protein. Although cohesin is required for the completion of meiotic recombination, little is known about how cohesin promotes the repair of meiotic DSBs and about the factors that promote loading of cohesin during meiosis. RESULTS Here we show that during Caenorhabditis elegans meiosis, loading of cohesin requires SCC-2, whereas the cohesin-related complexes condensin and SMC-5/6 can be loaded by mechanisms independent of both SCC-2 and cohesin. Although the lack of cohesin in scc-2 mutants impairs the repair of meiotic DSBs, surprisingly, the persistent DNA damage fails to trigger an apoptotic response of the conserved pachytene DNA damage checkpoint. Mutants carrying an scc-3 allele that abrogates loading of meiotic cohesin are also deficient in the apoptotic response of the pachytene checkpoint, and both scc-2 and scc-3 mutants fail to recruit the DNA damage sensor 9-1-1 complex onto persistent damage sites during meiosis. Furthermore, we show that meiotic cohesin is also required for the timely loading of the RAD-51 recombinase to irradiation-induced DSBs. CONCLUSIONS We propose that meiotic cohesin promotes DSB processing and recruitment of DNA damage checkpoint proteins, thus implicating cohesin in the earliest steps of the DNA damage response during meiosis.
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Affiliation(s)
- James Lightfoot
- MRC Clinical Sciences Centre, Faculty of Medicine, Imperial College London, London W12 0NN, UK
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36
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Watts FZ, Hoffmann E. SUMO meets meiosis: an encounter at the synaptonemal complex: SUMO chains and sumoylated proteins suggest that heterogeneous and complex interactions lie at the centre of the synaptonemal complex. Bioessays 2011; 33:529-37. [PMID: 21590786 DOI: 10.1002/bies.201100002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Recent discoveries have identified the small ubiquitin-like modifier (SUMO) as the potential 'missing link' that could explain how the synaptonemal complex (SC) is formed during meiosis. The SC is important for a variety of chromosome interactions during meiosis and appears ladder-like. It is formed when 'axes' of the two homologous chromosomes become connected by the deposition of transverse filaments, forming the steps of the ladder. Although several components of axial and transverse elements have been identified, how the two are connected to form the SC has remained an enigma. Recent discoveries suggest that SUMO modification underlies protein-protein interactions within the SC of budding yeast. The versatility of SUMO in regulating protein-protein interactions adds an exciting new dimension to our understanding of the SC and suggests that SCs are not homogenous structures throughout the nucleus. We propose that this heterogeneity may allow differential regulation of chromosome structure and function.
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Affiliation(s)
- Felicity Z Watts
- MRC Genome Damage and Stability Centre, University of Sussex, Falmer, UK.
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37
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Vranis NM, Van der Heijden GW, Malki S, Bortvin A. Synaptonemal complex length variation in wild-type male mice. Genes (Basel) 2010; 1:505-20. [PMID: 24710100 PMCID: PMC3966217 DOI: 10.3390/genes1030505] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 11/18/2010] [Accepted: 12/08/2010] [Indexed: 11/16/2022] Open
Abstract
Meiosis yields haploid gametes following two successive divisions of a germ cell in the absence of intervening DNA replication. Balanced segregation of homologous chromosomes in Meiosis I is aided by a proteinaceous structure, the synaptonemal complex (SC). The objective of this study was to determine total average autosomal SC lengths in spermatocytes in three commonly used mouse strains (129S4/SvJae, C57BL/6J, and BALB/c). Our experiments revealed that the total autosomal SC length in BALB/c spermatocytes is 9% shorter than in the two other strains. Shorter SCs are also observed in spermatocytes of (BALB/c × 129S4/SvJae) and (C57BL/6J × BALB/c) F1 hybrids suggesting a genetic basis of SC length regulation. Along these lines, we studied expression of a selected group of genes implicated in meiotic chromosome architecture. We found that BALB/c testes express up to 6-fold less of Rec8 mRNA and 4-fold less of REC8 protein. These results suggest that the mechanism that defines the SC length operates via a REC8‑dependent process. Finally, our results demonstrate that genetic background can have an effect on meiotic studies in mice.
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Affiliation(s)
| | | | - Safia Malki
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA.
| | - Alex Bortvin
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218, USA.
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Kim KP, Weiner BM, Zhang L, Jordan A, Dekker J, Kleckner N. Sister cohesion and structural axis components mediate homolog bias of meiotic recombination. Cell 2010; 143:924-37. [PMID: 21145459 PMCID: PMC3033573 DOI: 10.1016/j.cell.2010.11.015] [Citation(s) in RCA: 198] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 10/19/2010] [Accepted: 10/21/2010] [Indexed: 11/19/2022]
Abstract
Meiotic double-strand break (DSB)-initiated recombination must occur between homologous maternal and paternal chromosomes ("homolog bias"), even though sister chromatids are present. Through physical recombination analyses, we show that sister cohesion, normally mediated by meiotic cohesin Rec8, promotes "sister bias"; that meiosis-specific axis components Red1/Mek1kinase counteract this effect, thereby satisfying an essential precondition for homolog bias; and that other components, probably recombinosome-related, directly ensure homolog partner selection. Later, Rec8 acts positively to ensure maintenance of bias. These complexities mirror opposing dictates for global sister cohesion versus local separation and differentiation of sisters at recombination sites. Our findings support DSB formation within axis-tethered recombinosomes containing both sisters and ensuing programmed sequential release of "first" and "second" DSB ends. First-end release would create a homology-searching "tentacle." Rec8 and Red1/Mek1 also independently license recombinational progression and abundantly localize to different domains. These domains could comprise complementary environments that integrate inputs from DSB repair and mitotic chromosome morphogenesis into the complete meiotic program.
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Affiliation(s)
- Keun P. Kim
- Department of Molecular and Cellular Biology Harvard University, 7 Divinity Avenue Cambridge, MA 02138 USA
| | - Beth M. Weiner
- Department of Molecular and Cellular Biology Harvard University, 7 Divinity Avenue Cambridge, MA 02138 USA
| | - Liangran Zhang
- Department of Molecular and Cellular Biology Harvard University, 7 Divinity Avenue Cambridge, MA 02138 USA
| | - Amy Jordan
- Department of Molecular and Cellular Biology Harvard University, 7 Divinity Avenue Cambridge, MA 02138 USA
| | - Job Dekker
- Department of Molecular and Cellular Biology Harvard University, 7 Divinity Avenue Cambridge, MA 02138 USA
- Program in Gene Function and Expression and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester MA 01655 USA
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology Harvard University, 7 Divinity Avenue Cambridge, MA 02138 USA
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39
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Abstract
Sister chromatids are held together from the time of their formation in S phase until they segregate in anaphase by the cohesin complex. In meiosis of most organisms, the mitotic Mcd1/Scc1/Rad21 subunit of the cohesin complex is largely replaced by its paralog named Rec8. This article reviews the specialized functions of Rec8 that are crucial for diverse aspects of chromosome dynamics in meiosis, and presents some speculations relating to meiotic chromosome organization.
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40
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Storlazzi A, Gargano S, Ruprich-Robert G, Falque M, David M, Kleckner N, Zickler D. Recombination proteins mediate meiotic spatial chromosome organization and pairing. Cell 2010; 141:94-106. [PMID: 20371348 DOI: 10.1016/j.cell.2010.02.041] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 04/28/2009] [Accepted: 02/11/2010] [Indexed: 11/26/2022]
Abstract
Meiotic chromosome pairing involves not only recognition of homology but also juxtaposition of entire chromosomes in a topologically regular way. Analysis of filamentous fungus Sordaria macrospora reveals that recombination proteins Mer3, Msh4, and Mlh1 play direct roles in all of these aspects, in advance of their known roles in recombination. Absence of Mer3 helicase results in interwoven chromosomes, thereby revealing the existence of features that specifically ensure "entanglement avoidance." Entanglements that remain at zygotene, i.e., "interlockings," require Mlh1 for resolution, likely to eliminate constraining recombinational connections. Patterns of Mer3 and Msh4 foci along aligned chromosomes show that the double-strand breaks mediating homologous alignment have spatially separated ends, one localized to each partner axis, and that pairing involves interference among developing interhomolog interactions. We propose that Mer3, Msh4, and Mlh1 execute all of these roles during pairing by modulating the state of nascent double-strand break/partner DNA contacts within axis-associated recombination complexes.
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Affiliation(s)
- Aurora Storlazzi
- Institut de Génétique et Microbiologie, UMR 8621, Université Paris-Sud, 91405 Orsay, France
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41
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De novo assembly of a 40 Mb eukaryotic genome from short sequence reads: Sordaria macrospora, a model organism for fungal morphogenesis. PLoS Genet 2010; 6:e1000891. [PMID: 20386741 PMCID: PMC2851567 DOI: 10.1371/journal.pgen.1000891] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 03/02/2010] [Indexed: 01/09/2023] Open
Abstract
Filamentous fungi are of great importance in ecology, agriculture, medicine, and biotechnology. Thus, it is not surprising that genomes for more than 100 filamentous fungi have been sequenced, most of them by Sanger sequencing. While next-generation sequencing techniques have revolutionized genome resequencing, e.g. for strain comparisons, genetic mapping, or transcriptome and ChIP analyses, de novo assembly of eukaryotic genomes still presents significant hurdles, because of their large size and stretches of repetitive sequences. Filamentous fungi contain few repetitive regions in their 30-90 Mb genomes and thus are suitable candidates to test de novo genome assembly from short sequence reads. Here, we present a high-quality draft sequence of the Sordaria macrospora genome that was obtained by a combination of Illumina/Solexa and Roche/454 sequencing. Paired-end Solexa sequencing of genomic DNA to 85-fold coverage and an additional 10-fold coverage by single-end 454 sequencing resulted in approximately 4 Gb of DNA sequence. Reads were assembled to a 40 Mb draft version (N50 of 117 kb) with the Velvet assembler. Comparative analysis with Neurospora genomes increased the N50 to 498 kb. The S. macrospora genome contains even fewer repeat regions than its closest sequenced relative, Neurospora crassa. Comparison with genomes of other fungi showed that S. macrospora, a model organism for morphogenesis and meiosis, harbors duplications of several genes involved in self/nonself-recognition. Furthermore, S. macrospora contains more polyketide biosynthesis genes than N. crassa. Phylogenetic analyses suggest that some of these genes may have been acquired by horizontal gene transfer from a distantly related ascomycete group. Our study shows that, for typical filamentous fungi, de novo assembly of genomes from short sequence reads alone is feasible, that a mixture of Solexa and 454 sequencing substantially improves the assembly, and that the resulting data can be used for comparative studies to address basic questions of fungal biology.
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Abstract
All organisms, from bacteria to humans, face the daunting task of replicating, packaging and segregating up to two metres (about 6 x 10(9) base pairs) of DNA when each cell divides. This task is carried out up to a trillion times during the development of a human from a single fertilized cell. The strategy by which DNA is replicated is now well understood. But when it comes to packaging and segregating a genome, the mechanisms are only beginning to be understood and are often as variable as the organisms in which they are studied.
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Jin H, Guacci V, Yu HG. Pds5 is required for homologue pairing and inhibits synapsis of sister chromatids during yeast meiosis. ACTA ACUST UNITED AC 2009; 186:713-25. [PMID: 19736318 PMCID: PMC2742186 DOI: 10.1083/jcb.200810107] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A meiosis-conditional pds5 allele in yeast provides a more detailed understanding of homologue pairing and synaptonemal complex formation. During meiosis, homologues become juxtaposed and synapsed along their entire length. Mutations in the cohesin complex disrupt not only sister chromatid cohesion but also homologue pairing and synaptonemal complex formation. In this study, we report that Pds5, a cohesin-associated protein known to regulate sister chromatid cohesion, is required for homologue pairing and synapsis in budding yeast. Pds5 colocalizes with cohesin along the length of meiotic chromosomes. In the absence of Pds5, the meiotic cohesin subunit Rec8 remains bound to chromosomes with only minor defects in sister chromatid cohesion, but sister chromatids synapse instead of homologues. Double-strand breaks (DSBs) are formed but are not repaired efficiently. In addition, meiotic chromosomes undergo hypercondensation. When the mitotic cohesin subunit Mcd1 is substituted for Rec8 in Pds5-depleted cells, chromosomes still hypercondense, but synapsis of sister chromatids is abolished. These data suggest that Pds5 modulates the Rec8 activity to facilitate chromosome morphological changes required for homologue synapsis, DSB repair, and meiotic chromosome segregation.
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Affiliation(s)
- Hui Jin
- Department of Biological Science, The Florida State University, Tallahassee, FL 32306, USA
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Viera A, Santos JL, Parra MT, Calvente A, Gómez R, de la Fuente R, Suja JA, Page J, Rufas JS. Cohesin axis maturation and presence of RAD51 during first meiotic prophase in a true bug. Chromosoma 2009; 118:575-89. [PMID: 19495784 DOI: 10.1007/s00412-009-0218-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 04/28/2009] [Accepted: 05/09/2009] [Indexed: 11/26/2022]
Abstract
We have analyzed in a true bug, Graphosoma italicum (Pentatomidae, Hemiptera), the temporal and functional relationships between recombination events, synapsis progression, and SMC1alpha and SMC3 cohesin axis maturation throughout the male first meiotic prophase. The localization of the histone variant histone H3 trimethylated at lysine 9 at chromosome ends has allowed us to determine the association of these heterochromatic domains through prophase I stages. Results highlighted that cohesins provide to be good markers for synapsis progression since the formation, morphology, and development of the SMC1alpha and SMC3 cohesin axes resemble the synaptonemal complex dynamics and, also, that in this species the initiation of recombination precedes synapsis. In addition, we have carried out an accurate cytological characterization of the diffuse stage, which takes place after pachytene, and also analyzed the presence of the cohesin subunits, SMC1alpha and SMC3, and the recombinase RAD51 at this stage. The mechanisms underlying the absence of SMC1alpha and SMC3 axes from the diffuse stage onwards are discussed.
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Affiliation(s)
- Alberto Viera
- Departamento de Biología, Edificio de Biológicas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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Joshi N, Barot A, Jamison C, Börner GV. Pch2 links chromosome axis remodeling at future crossover sites and crossover distribution during yeast meiosis. PLoS Genet 2009; 5:e1000557. [PMID: 19629172 PMCID: PMC2708914 DOI: 10.1371/journal.pgen.1000557] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 06/10/2009] [Indexed: 01/10/2023] Open
Abstract
Segregation of homologous chromosomes during meiosis I depends on appropriately positioned crossovers/chiasmata. Crossover assurance ensures at least one crossover per homolog pair, while interference reduces double crossovers. Here, we have investigated the interplay between chromosome axis morphogenesis and non-random crossover placement. We demonstrate that chromosome axes are structurally modified at future crossover sites as indicated by correspondence between crossover designation marker Zip3 and domains enriched for axis ensemble Hop1/Red1. This association is first detected at the zygotene stage, persists until double Holliday junction resolution, and is controlled by the conserved AAA+ ATPase Pch2. Pch2 further mediates crossover interference, although it is dispensable for crossover formation at normal levels. Thus, interference appears to be superimposed on underlying mechanisms of crossover formation. When recombination-initiating DSBs are reduced, Pch2 is also required for viable spore formation, consistent with further functions in chiasma formation. pch2Δ mutant defects in crossover interference and spore viability at reduced DSB levels are oppositely modulated by temperature, suggesting contributions of two separable pathways to crossover control. Roles of Pch2 in controlling both chromosome axis morphogenesis and crossover placement suggest linkage between these processes. Pch2 is proposed to reorganize chromosome axes into a tiling array of long-range crossover control modules, resulting in chiasma formation at minimum levels and with maximum spacing. In the germ line of sexually reproducing organisms, haploid gametes are generated from diploid precursor cells by a specialized cell division called meiosis. Reduction by half of chromosome numbers during the first meiotic division depends on genetic exchange, resulting in the formation of crossovers. Without crossovers, pairs of homologous chromosomes frequently fail to separate, resulting in unbalanced gametes with a surplus or deficit of individual chromosomes. Along a given chromosome, crossovers form in different locations in different cells, but distribution of crossovers within each cell is controlled in two ways: first, at least one crossover is formed along each homolog pair, irrespective of size; second, a crossover in a given interval reduces the frequency of crossovers in adjacent chromosome regions. Here, we identify functions of the evolutionarily conserved protein Pch2 in suppressing additional crossovers in adjacent regions and ensuring homolog segregation under certain conditions. Pch2 further controls the assembly of chromosome axis protein Hop1 at future crossover sites. Our findings reveal that chromosome axes undergo structural changes at the same positions where crossovers occur. Thus, axis remodeling and crossover placement are linked via Pch2.
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Affiliation(s)
- Neeraj Joshi
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
| | - Aekam Barot
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
| | - Christine Jamison
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
| | - G. Valentin Börner
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
- * E-mail:
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Viera A, Santos JL, Rufas JS. Relationship between incomplete synapsis and chiasma localization. Chromosoma 2009; 118:377-89. [PMID: 19238420 DOI: 10.1007/s00412-009-0204-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 01/27/2009] [Accepted: 01/27/2009] [Indexed: 12/29/2022]
Abstract
One of the subjects within the meiotic field that has been actively investigated in the recent years is the temporal and functional relationships between meiotic recombination, cohesin loading and synaptonemal complex (SC) assembly. Although the study of meiotic mutants has shed some light, many questions remain to be answered. Here, we have studied this topic in the orthopteran Paratettix meridionalis, a species with telocentric chromosomes, which shows two unusual cytological features: pairing and synapsis of homologues during prophase I are restricted to the non-centromeric distal regions and extremely distal chiasma localization in metaphase I bivalents. In order to determine whether there is a relationship between both phenomena, we have used: (1) a spreading technique for following the ultrastructure of SC assembly and (2) immunofluorescence for SMC3 and SMC1alpha cohesin subunits, which mark the development of the axial element (a SC component); the histone gamma-H2AX, which mostly labels the sites of double-strand breaks; and the recombinase RAD51. Spermatocytes showed conspicuous polarization of both the maturation of cohesin axes and the initiation of meiotic recombination events. Consequently, it is proposed that maturation of cohesin axes, which begins in very distal regions, could drive the latter loading of recombinases to such regions. This restricted distribution of recombination events along homologues would finally be responsible for the incomplete pairing and synapsis observed in all autosomes of the complement and hence for chiasma localization.
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Affiliation(s)
- Alberto Viera
- Departamento de Biología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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Martinez-Perez E, Colaiácovo MP. Distribution of meiotic recombination events: talking to your neighbors. Curr Opin Genet Dev 2009; 19:105-12. [PMID: 19328674 DOI: 10.1016/j.gde.2009.02.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2009] [Revised: 02/16/2009] [Accepted: 02/19/2009] [Indexed: 12/30/2022]
Abstract
Accurate chromosome segregation during meiosis is essential for a species' survival. Therefore, a series of events unfold during meiosis, including pairing, synapsis, and recombination between homologous chromosomes, to ultimately ensure the successful completion of this task. This review will focus on how the regulation of crossover recombination events between homologous chromosomes plays a key role in promoting faithful segregation. Although our understanding of the molecular mechanisms by which crossovers are formed has increased significantly, the mechanisms governing the distribution of crossovers along meiotic chromosomes remain largely mysterious. Here, we review the different levels of apparent control of meiotic crossover formation and distribution.
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Affiliation(s)
- Enrique Martinez-Perez
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
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Martinez-Perez E, Schvarzstein M, Barroso C, Lightfoot J, Dernburg AF, Villeneuve AM. Crossovers trigger a remodeling of meiotic chromosome axis composition that is linked to two-step loss of sister chromatid cohesion. Genes Dev 2008; 22:2886-901. [PMID: 18923085 DOI: 10.1101/gad.1694108] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Segregation of homologous chromosomes during meiosis depends on linkages (chiasmata) created by crossovers and on selective release of a subset of sister chromatid cohesion at anaphase I. During Caenorhabditis elegans meiosis, each chromosome pair forms a single crossover, and the position of this event determines which chromosomal regions will undergo cohesion release at anaphase I. Here we provide insight into the basis of this coupling by uncovering a large-scale regional change in chromosome axis composition that is triggered by crossovers. We show that axial element components HTP-1 and HTP-2 are removed during late pachytene, in a crossover-dependent manner, from the regions that will later be targeted for anaphase I cohesion release. We demonstrate correspondence in position and number between chiasmata and HTP-1/2-depleted regions and provide evidence that HTP-1/2 depletion boundaries mark crossover sites. In htp-1 mutants, diakinesis bivalents lack normal asymmetrical features, and sister chromatid cohesion is prematurely lost during the meiotic divisions. We conclude that HTP-1 is central to the mechanism linking crossovers with late-prophase bivalent differentiation and defines the domains where cohesion will be protected until meiosis II. Further, we discuss parallels between the pattern of HTP-1/2 removal in response to crossovers and the phenomenon of crossover interference.
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Affiliation(s)
- Enrique Martinez-Perez
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
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Bhalla N, Wynne DJ, Jantsch V, Dernburg AF. ZHP-3 acts at crossovers to couple meiotic recombination with synaptonemal complex disassembly and bivalent formation in C. elegans. PLoS Genet 2008; 4:e1000235. [PMID: 18949042 PMCID: PMC2567099 DOI: 10.1371/journal.pgen.1000235] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 09/22/2008] [Indexed: 12/24/2022] Open
Abstract
Crossover recombination and the formation of chiasmata normally ensure the proper segregation of homologous chromosomes during the first meiotic division. zhp-3, the Caenorhabditis elegans ortholog of the budding yeast ZIP3 gene, is required for crossover recombination. We show that ZHP-3 protein localization is highly dynamic. At a key transition point in meiotic prophase, the protein shifts from along the length of the synaptonemal complex (SC) to an asymmetric localization on the SC and eventually becomes restricted to foci that mark crossover recombination events. A zhp-3::gfp transgene partially complements a null mutation and reveals a separation of function; although the fusion protein can promote nearly wild-type levels of recombination, aneuploidy among the progeny is high, indicating defects in meiotic chromosome segregation. The structure of bivalents is perturbed in this mutant, suggesting that the chromosome segregation defect results from an inability to properly remodel chromosomes in response to crossovers. smo-1 mutants exhibit phenotypes similar to zhp-3::gfp mutants at higher temperatures, and smo-1; zhp-3::gfp double mutants exhibit more severe meiotic defects than either single mutant, consistent with a role for SUMO in the process of SC disassembly and bivalent differentiation. We propose that coordination of crossover recombination with SC disassembly and bivalent formation reflects a conserved role of Zip3/ZHP-3 in coupling recombination with SC morphogenesis. Sexual reproduction relies on meiosis. This specialized cell division generates gametes, such as sperm and eggs, with a single copy of the genome, so that fertilization restores diploidy. In order for chromosomes to segregate correctly during meiosis, homologs usually must undergo crossing over (genetic exchange) during meiotic prophase. How crossovers are coupled to large-scale changes in chromosome structure is not well understood. Our work shows that the protein ZHP-3 localizes to crossovers late in prophase, coincident with a transition in which chromosomes initiate progressive restructuring around the crossover. We have found that a ZHP-3-GFP fusion protein is competent to promote genetic exchange but not proper segregation. Chromosomes from these mutant animals exhibit defects in this late-prophase restructuring, suggesting that alterations in chromosome architecture that typically accompany crossovers have not occurred. We propose that ZHP-3 acts at crossovers to coordinate genetic exchange with higher order changes in chromosome structure that promote proper chromosome segregation.
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Affiliation(s)
- Needhi Bhalla
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
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50
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Coprinus cinereus rad50 mutants reveal an essential structural role for Rad50 in axial element and synaptonemal complex formation, homolog pairing and meiotic recombination. Genetics 2008; 180:1889-907. [PMID: 18940790 DOI: 10.1534/genetics.108.092775] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Mre11/Rad50/Nbs1 (MRN) complex is required for eukaryotic DNA double-strand break (DSB) repair and meiotic recombination. We cloned the Coprinus cinereus rad50 gene and showed that it corresponds to the complementation group previously named rad12, identified mutations in 15 rad50 alleles, and mapped two of the mutations onto molecular models of Rad50 structure. We found that C. cinereus rad50 and mre11 mutants arrest in meiosis and that this arrest is Spo11 dependent. In addition, some rad50 alleles form inducible, Spo11-dependent Rad51 foci and therefore must be forming meiotic DSBs. Thus, we think it likely that arrest in both mre11-1 and the collection of rad50 mutants is the result of unrepaired or improperly processed DSBs in the genome and that Rad50 and Mre11 are dispensable in C. cinereus for DSB formation, but required for appropriate DSB processing. We found that the ability of rad50 mutant strains to form Rad51 foci correlates with their ability to promote synaptonemal complex formation and with levels of stable meiotic pairing and that partial pairing, recombination initiation, and synapsis occur in the absence of wild-type Rad50 catalytic domains. Examination of single- and double-mutant strains showed that a spo11 mutation that prevents DSB formation enhances axial element (AE) formation for rad50-4, an allele predicted to encode a protein with intact hook region and hook-proximal coiled coils, but not for rad50-1, an allele predicted to encode a severely truncated protein, or for rad50-5, which encodes a protein whose hook-proximal coiled-coil region is disrupted. Therefore, Rad50 has an essential structural role in the formation of AEs, separate from the DSB-processing activity of the MRN complex.
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