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Huang Y, Liu Y, Guo X, Fan C, Yi C, Shi Q, Su H, Liu C, Yuan J, Liu D, Yang W, Han F. New insights on the evolution of nucleolar dominance in newly resynthesized hexaploid wheat Triticum zhukovskyi. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1298-1315. [PMID: 37246611 DOI: 10.1111/tpj.16320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/11/2023] [Accepted: 05/23/2023] [Indexed: 05/30/2023]
Abstract
Nucleolar dominance (ND) is a widespread epigenetic phenomenon in hybridizations where nucleolus transcription fails at the nucleolus organizer region (NOR). However, the dynamics of NORs during the formation of Triticum zhukovskyi (GGAu Au Am Am ), another evolutionary branch of allohexaploid wheat, remains poorly understood. Here, we elucidated genetic and epigenetic changes occurring at the NOR loci within the Am , G, and D subgenomes during allopolyploidization by synthesizing hexaploid wheat GGAu Au Am Am and GGAu Au DD. In T. zhukovskyi, Au genome NORs from T. timopheevii (GGAu Au ) were lost, while the second incoming NORs from T. monococcum (Am Am ) were retained. Analysis of the synthesized T. zhukovskyi revealed that rRNA genes from the Am genome were silenced in F1 hybrids (GAu Am ) and remained inactive after genome doubling and subsequent self-pollinations. We observed increased DNA methylation accompanying the inactivation of NORs in the Am genome and found that silencing of NORs in the S1 generation could be reversed by a cytidine methylase inhibitor. Our findings provide insights into the ND process during the evolutionary period of T. zhukovskyi and highlight that inactive rDNA units may serve as a 'first reserve' in the form of R-loops, contributing to the successful evolution of T. zhukovskyi.
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Affiliation(s)
- Yuhong Huang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xianrui Guo
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chaolan Fan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Congyang Yi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qinghua Shi
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Handong Su
- Huazhong Agricultural University, Hubei, 430070, China
| | - Chang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Yuan
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
| | - Dengcai Liu
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Wuyun Yang
- Crop Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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2
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Tsubouchi H. The Hop2-Mnd1 Complex and Its Regulation of Homologous Recombination. Biomolecules 2023; 13:biom13040662. [PMID: 37189409 DOI: 10.3390/biom13040662] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/06/2023] [Accepted: 04/07/2023] [Indexed: 05/17/2023] Open
Abstract
Homologous recombination (HR) is essential for meiosis in most sexually reproducing organisms, where it is induced upon entry into meiotic prophase. Meiotic HR is conducted by the collaborative effort of proteins responsible for DNA double-strand break repair and those produced specifically during meiosis. The Hop2-Mnd1 complex was originally identified as a meiosis-specific factor that is indispensable for successful meiosis in budding yeast. Later, it was found that Hop2-Mnd1 is conserved from yeasts to humans, playing essential roles in meiosis. Accumulating evidence suggests that Hop2-Mnd1 promotes RecA-like recombinases towards homology search/strand exchange. This review summarizes studies on the mechanism of the Hop2-Mnd1 complex in promoting HR and beyond.
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Affiliation(s)
- Hideo Tsubouchi
- Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Kanagawa, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8503, Kanagawa, Japan
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Steckenborn S, Cuacos M, Ayoub MA, Feng C, Schubert V, Hoffie I, Hensel G, Kumlehn J, Heckmann S. The meiotic topoisomerase VI B subunit (MTOPVIB) is essential for meiotic DNA double-strand break formation in barley (Hordeum vulgare L.). PLANT REPRODUCTION 2023; 36:1-15. [PMID: 35767067 PMCID: PMC9957907 DOI: 10.1007/s00497-022-00444-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/31/2022] [Indexed: 06/01/2023]
Abstract
In barley (Hordeum vulgare), MTOPVIB is critical for meiotic DSB and accompanied SC and CO formation while dispensable for meiotic bipolar spindle formation. Homologous recombination during meiosis assures genetic variation in offspring. Programmed meiotic DNA double-strand breaks (DSBs) are repaired as crossover (CO) or non-crossover (NCO) during meiotic recombination. The meiotic topoisomerase VI (TopoVI) B subunit (MTOPVIB) plays an essential role in meiotic DSB formation critical for CO-recombination. More recently MTOPVIB has been also shown to play a role in meiotic bipolar spindle formation in rice and maize. Here, we describe a meiotic DSB-defective mutant in barley (Hordeum vulgare L.). CRISPR-associated 9 (Cas9) endonuclease-generated mtopVIB plants show complete sterility due to the absence of meiotic DSB, synaptonemal complex (SC), and CO formation leading to the occurrence of univalents and their unbalanced segregation into aneuploid gametes. In HvmtopVIB plants, we also frequently found the bi-orientation of sister kinetochores in univalents during metaphase I and the precocious separation of sister chromatids during anaphase I. Moreover, the near absence of polyads after meiosis II, suggests that despite being critical for meiotic DSB formation in barley, MTOPVIB seems not to be strictly required for meiotic bipolar spindle formation.
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Affiliation(s)
- Stefan Steckenborn
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Maria Cuacos
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Mohammad A Ayoub
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Chao Feng
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Iris Hoffie
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Götz Hensel
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Jochen Kumlehn
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany
| | - Stefan Heckmann
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) OT Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany.
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Daradur J, Kesserwan M, Freese NH, Loraine AE, Riggs CD. Genomic targets of HOP2 are enriched for features found at recombination hotspots. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525520. [PMID: 36747711 PMCID: PMC9900786 DOI: 10.1101/2023.01.25.525520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
HOP2 is a conserved protein that plays a positive role in homologous chromosome pairing and a separable role in preventing illegitimate connections between nonhomologous chromosome regions during meiosis. We employed ChIP-seq to discover that Arabidopsis HOP2 binds along the length of all chromosomes, except for centromeric and nucleolar organizer regions, and no binding sites were detected in the organelle genomes. A large number of reads were assigned to the HOP2 locus itself, yet TAIL-PCR and SNP analysis of the aligned sequences indicate that many of these reads originate from the transforming T-DNA, supporting the role of HOP2 in preventing nonhomologous exchanges. The 292 ChIP-seq peaks are largely found in promoter regions and downstream from genes, paralleling the distribution of recombination hotspots, and motif analysis revealed that there are several conserved sequences that are also enriched at crossover sites. We conducted coimmunoprecipitation of HOP2 followed by LC-MS/MS and found enrichment for several proteins, including some histone variants and modifications that are also known to be associated with recombination hotspots. We propose that HOP2 may be directed to chromatin motifs near double strand breaks, where homology checks are proposed to occur.
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Affiliation(s)
- Jenya Daradur
- Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C1A4, Canada
| | - Mohamad Kesserwan
- Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C1A4, Canada
| | - Nowlan H. Freese
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, Charlotte, N.C. USA
| | - Ann E. Loraine
- Department of Bioinformatics and Genomics, University of North Carolina, Charlotte, Charlotte, N.C. USA
| | - C. Daniel Riggs
- Department of Biological Sciences, University of Toronto, Toronto, Ontario M1C1A4, Canada
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Farahani-Tafreshi Y, Wei C, Gan P, Daradur J, Riggs CD, Hasenkampf CA. The Arabidopsis HOP2 gene has a role in preventing illegitimate connections between nonhomologous chromosome regions. Chromosome Res 2022; 30:59-75. [DOI: 10.1007/s10577-021-09681-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/04/2021] [Accepted: 12/08/2021] [Indexed: 11/03/2022]
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Lu J, Wang C, Wang H, Zheng H, Bai W, Lei D, Tian Y, Xiao Y, You S, Wang Q, Yu X, Liu S, Liu X, Chen L, Jang L, Wang C, Zhao Z, Wan J. OsMFS1/ OsHOP2 Complex Participates in Rice Male and Female Development. FRONTIERS IN PLANT SCIENCE 2020; 11:518. [PMID: 32499797 PMCID: PMC7243175 DOI: 10.3389/fpls.2020.00518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/06/2020] [Indexed: 05/08/2023]
Abstract
Meiosis plays an essential role in the production of gametes and genetic diversity of posterities. The normal double-strand break (DSB) repair is vital to homologous recombination (HR) and occurrence of DNA fragment exchange, but the underlying molecular mechanism remain elusive. Here, we characterized a completely sterile Osmfs1 (male and female sterility 1) mutant which has its pollen and embryo sacs both aborted at the reproductive stage due to severe chromosome defection. Map-based cloning revealed that the OsMFS1 encodes a meiotic coiled-coil protein, and it is responsible for DSB repairing that acts as an important cofactor to stimulate the single strand invasion. Expression pattern analyses showed the OsMFS1 was preferentially expressed in meiosis stage. Subcellular localization analysis of OsMFS1 revealed its association with the nucleus exclusively. In addition, a yeast two-hybrid (Y2H) and pull-down assay showed that OsMFS1 could physically interact with OsHOP2 protein to form a stable complex to ensure faithful homologous recombination. Taken together, our results indicated that OsMFS1 is indispensable to the normal development of anther and embryo sacs in rice.
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Affiliation(s)
- Jiayu Lu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Chaolong Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Haiyu Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Hai Zheng
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Wenting Bai
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Dekun Lei
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yunlu Tian
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yanjia Xiao
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Shimin You
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Qiming Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Xiaowen Yu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Shijia Liu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Xi Liu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Liangming Chen
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Ling Jang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Chunming Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Zhigang Zhao
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
- *Correspondence: Zhigang Zhao,
| | - Jianmin Wan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
- Jianmin Wan, ;
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7
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Shi W, Tang D, Shen Y, Xue Z, Zhang F, Zhang C, Ren L, Liu C, Du G, Li Y, Yan C, Cheng Z. OsHOP2 regulates the maturation of crossovers by promoting homologous pairing and synapsis in rice meiosis. THE NEW PHYTOLOGIST 2019; 222:805-819. [PMID: 30584664 DOI: 10.1111/nph.15664] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 12/07/2018] [Indexed: 05/07/2023]
Abstract
Meiotic recombination is closely linked with homologous pairing and synapsis. Previous studies have shown that HOMOLOGOUS PAIRING PROTEIN2 (HOP2), plays an essential role in homologous pairing and synapsis. However, the mechanism by which HOP2 regulates crossover (CO) formation has not been elucidated. Here, we show that OsHOP2 mediates the maturation of COs by promoting homologous pairing and synapsis in rice (Oryza sativa) meiosis. We used a combination of genetic analysis, immunolocalization and super-resolution imaging to analyze the function of OsHOP2 in rice meiosis. We showed that full-length pairing, synapsis and CO formation are disturbed in Oshop2 meiocytes. Moreover, structured illumination microscopy showed that OsHOP2 localized to chromatin and displayed considerable co-localization with axial elements (AEs) and central elements (CEs). Importantly, the interaction between OsHOP2 and a transverse filament protein of synaptonemal complex (ZEP1), provided further evidence that OsHOP2 was involved in assembly or stabilization of the structure of the synaptonemal complex (SC). Although the initiation of recombination and CO designation occur normally in Oshop2 mutants, mature COs were severely reduced, and human enhancer of invasion 10 (HEI10)10 foci were only present on the synapsed region. Putting the data together, we speculate that OsHOP2 may serve as a global regulator to coordinate homologous pairing, synapsis and meiotic recombination in rice meiosis.
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Affiliation(s)
- Wenqing Shi
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ding Tang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yi Shen
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhihui Xue
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fanfan Zhang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chao Zhang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lijun Ren
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Changzhen Liu
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guijie Du
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yafei Li
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Changjie Yan
- Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Zhukuan Cheng
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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8
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Abstract
Production of gametes of halved ploidy for sexual reproduction requires a specialized cell division called meiosis. The fusion of two gametes restores the original ploidy in the new generation, and meiosis thus stabilizes ploidy across generations. To ensure balanced distribution of chromosomes, pairs of homologous chromosomes (homologs) must recognize each other and pair in the first meiotic division. Recombination plays a key role in this in most studied species, but it is not the only actor and particular chromosomal regions are known to facilitate the meiotic pairing of homologs. In this review, we focus on the roles of centromeres and in particular on the clustering and pairwise associations of nonhomologous centromeres that precede stable pairing between homologs. Although details vary from species to species, it is becoming increasingly clear that these associations play active roles in the meiotic chromosome pairing process, analogous to those of the telomere bouquet.
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Affiliation(s)
- Olivier Da Ines
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, Aubière, France; ,
| | - Charles I White
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, Aubière, France; ,
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9
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Mainiero S, Pawlowski WP. Meiotic chromosome structure and function in plants. Cytogenet Genome Res 2014; 143:6-17. [PMID: 25096046 DOI: 10.1159/000365260] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
Chromosome structure is important for many meiotic processes. Here, we outline 3 main determinants of chromosome structure and their effects on meiotic processes in plants. Cohesins are necessary to hold sister chromatids together until the first meiotic division, ensuring that homologous chromosomes and not sister chromatids separate during anaphase I. During meiosis in maize, Arabidopsis, and rice, cohesins are needed for establishing early prophase chromosome structure and recombination and for aligning bivalents at the metaphase plate. Condensin complexes play pivotal roles in controlling the packaging of chromatin into chromosomes through chromatin compaction and chromosome individualization. In animals and fungi, these complexes establish a meiotic chromosome structure that allows for proper recombination, pairing, and synapsis of homologous chromosomes. In plants, information on the role of condensins in meiosis is limited, but they are known to be required for successful completion of reproductive development. Therefore, we speculate that they play roles similar to animal and fungal condensins during meiosis. Plants generally have large and complex genomes due to frequent polyploidy events, and likely, condensins and cohesins organize chromosomes in such a way as to ensure genome stability. Hexaploid wheat has evolved a unique mechanism using a Ph1 locus-controlled chromosome organization to ensure proper chromosome pairing in meiosis. Altogether, studies on meiotic chromosome structure indicate that chromosome organization is not only important for chromatin packaging but also fulfills specific functions in facilitating chromosome interactions during meiosis, including pairing and recombination.
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Affiliation(s)
- Samantha Mainiero
- Graduate Field of Plant Biology, Cornell University, Ithaca, N.Y., USA
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10
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Da Ines O, Gallego ME, White CI. Recombination-independent mechanisms and pairing of homologous chromosomes during meiosis in plants. MOLECULAR PLANT 2014; 7:492-501. [PMID: 24375719 DOI: 10.1093/mp/sst172] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Meiosis is the specialized eukaryotic cell division that permits the halving of ploidy necessary for gametogenesis in sexually reproducing organisms. This involves a single round of DNA replication followed by two successive divisions. To ensure balanced segregation, homologous chromosome pairs must migrate to opposite poles at the first meiotic division and this means that they must recognize and pair with each other beforehand. Although understanding of the mechanisms by which meiotic chromosomes find and pair with their homologs has greatly advanced, it remains far from being fully understood. With some notable exceptions such as male Drosophila, the recognition and physical linkage of homologs at the first meiotic division involves homologous recombination. However, in addition to this, it is clear that many organisms, including plants, have also evolved a series of recombination-independent mechanisms to facilitate homolog recognition and pairing. These implicate chromosome structure and dynamics, telomeres, centromeres, and, most recently, small RNAs. With a particular focus on plants, we present here an overview of understanding of these early, recombination-independent events that act in the pairing of homologous chromosomes during the first meiotic division.
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Affiliation(s)
- Olivier Da Ines
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, 63171 Aubière, France
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Uanschou C, Ronceret A, Von Harder M, De Muyt A, Vezon D, Pereira L, Chelysheva L, Kobayashi W, Kurumizaka H, Schlögelhofer P, Grelon M. Sufficient amounts of functional HOP2/MND1 complex promote interhomolog DNA repair but are dispensable for intersister DNA repair during meiosis in Arabidopsis. THE PLANT CELL 2013; 25:4924-40. [PMID: 24363313 PMCID: PMC3903996 DOI: 10.1105/tpc.113.118521] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
During meiosis, homologous recombination (HR) is essential to repair programmed DNA double-strand breaks (DSBs), and a dedicated protein machinery ensures that the homologous chromosome is favored over the nearby sister chromatid as a repair template. The homologous-pairing protein2/meiotic nuclear division protein1 (HOP2/MND1) protein complex has been identified as a crucial factor of meiotic HR in Arabidopsis thaliana, since loss of either MND1 or HOP2 results in failure of DNA repair. We isolated two mutant alleles of HOP2 (hop2-2 and hop2-3) that retained the capacity to repair meiotic DSBs via the sister chromatid but failed to use the homologous chromosome. We show that in these alleles, the recombinases radiation sensitive51 (RAD51) and disrupted meiotic cDNA1 (DMC1) are loaded, but only the intersister DNA repair pathway is activated. The hop2-2 phenotype is correlated with a decrease in HOP2/MND1 complex abundance. In hop2-3, a truncated HOP2 protein is produced that retains its ability to bind to DMC1 and DNA but forms less stable complexes with MND1 and fails to efficiently stimulate DMC1-driven D-loop formation. Genetic analyses demonstrated that in the absence of DMC1, HOP2/MND1 is dispensable for RAD51-mediated intersister DNA repair, while in the presence of DMC1, a minimal amount of functional HOP2/MND1 is essential to drive intersister DNA repair.
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Affiliation(s)
- Clemens Uanschou
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Arnaud Ronceret
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Mona Von Harder
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
| | - Arnaud De Muyt
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Daniel Vezon
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Lucie Pereira
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Liudmila Chelysheva
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
| | - Wataru Kobayashi
- Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hitoshi Kurumizaka
- Graduate School of Advanced Science and Engineering, Waseda University, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Peter Schlögelhofer
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
- Address correspondence to
| | - Mathilde Grelon
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
- AgroParisTech, Institut Jean-Pierre Bourgin, F-78000 Versailles, France
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12
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Pathan N, Stronghill P, Hasenkampf C. Transmission electron microscopy and serial reconstructions reveal novel meiotic phenotypes for the ahp2 mutant of Arabidopsis thaliana. Genome 2013; 56:139-45. [PMID: 23659697 DOI: 10.1139/gen-2012-0157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have found novel phenotypes for the previously studied Arabidopsis thaliana (L.) Heynh. meiotic mutant ahp2. These phenotypes were revealed by analysis of reconstructions of normal and ahp2 nuclei that were imaged using transmission electron microscopy. Previous studies of the ahp2 mutant demonstrated that it has a general failure to form synaptonemal complexes, except for the nucleolus organizing regions, and it fails to complete reciprocal genetic exchange. Here, we show that even though the ahp2 chromosome axes have only 5% of the normal amount of synaptonemal complex formation, it nonetheless has slightly more than 40% of the axes involved in close alignment. We also observed two striking nuclear envelope associated abnormalities. Wild type nuclei contain two nucleoli, one nucleolus-like structure, and nuclear envelope associated structures that we refer to as nuclear envelope associated disks. The ahp2 nuclei have the two nucleoli, but they lack the third nucleolus-like structure and instead have a previously uncharacterized structure that spans the nuclear envelope. Additionally, ahp2 meiocytes have nuclear envelope associated disks that are narrower and more numerous (∼2×) than those seen in wild type, and unlike the wild type disks, they are in direct contact with the nuclear envelope.
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Affiliation(s)
- Nazia Pathan
- Department of Biological Science, University of Toronto (Scarborough), Scarborough, ON M1C 1A4, Canada
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13
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Da Ines O, Abe K, Goubely C, Gallego ME, White CI. Differing requirements for RAD51 and DMC1 in meiotic pairing of centromeres and chromosome arms in Arabidopsis thaliana. PLoS Genet 2012; 8:e1002636. [PMID: 22532804 PMCID: PMC3330102 DOI: 10.1371/journal.pgen.1002636] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 02/21/2012] [Indexed: 11/18/2022] Open
Abstract
During meiosis homologous chromosomes pair, recombine, and synapse, thus ensuring accurate chromosome segregation and the halving of ploidy necessary for gametogenesis. The processes permitting a chromosome to pair only with its homologue are not fully understood, but successful pairing of homologous chromosomes is tightly linked to recombination. In Arabidopsis thaliana, meiotic prophase of rad51, xrcc3, and rad51C mutants appears normal up to the zygotene/pachytene stage, after which the genome fragments, leading to sterility. To better understand the relationship between recombination and chromosome pairing, we have analysed meiotic chromosome pairing in these and in dmc1 mutant lines. Our data show a differing requirement for these proteins in pairing of centromeric regions and chromosome arms. No homologous pairing of mid-arm or distal regions was observed in rad51, xrcc3, and rad51C mutants. However, homologous centromeres do pair in these mutants and we show that this does depend upon recombination, principally on DMC1. This centromere pairing extends well beyond the heterochromatic centromere region and, surprisingly, does not require XRCC3 and RAD51C. In addition to clarifying and bringing the roles of centromeres in meiotic synapsis to the fore, this analysis thus separates the roles in meiotic synapsis of DMC1 and RAD51 and the meiotic RAD51 paralogs, XRCC3 and RAD51C, with respect to different chromosome domains. Meiosis is a specialised cell division that acts to halve the chromosome complement, or ploidy, in the production of gametes for sexual reproduction in eukaryotes. To ensure that each gamete has a full complement of the genetic material, homologous chromosomes must pair and then separate in a coordinated manner during meiosis, and this is mediated by recombination in the majority of studied eukaryotes. To better understand the relationship between recombination and meiotic homologue pairing, we have analysed meiotic chromosome pairing in plant mutants lacking key recombination proteins. This work provides new insights into the homologous chromosome pairing mechanisms occurring in meiotic prophase of Arabidopsis thaliana: heterochromatic centromeres and 5S rDNA regions pair early, and their pairing has different requirements for recombination proteins than does that of the chromosome arms. These data raise a number of questions concerning the specificities and roles of recombination at different chromosome and/or chromatin regions in the synapsis of homologous chromosomes at meiosis.
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Affiliation(s)
| | | | | | | | - Charles I. White
- Génétique, Reproduction et Développement, UMR CNRS 6293, Clermont Université, INSERM U1103, Aubière, France
- * E-mail:
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14
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Tsai JH, McKee BD. Homologous pairing and the role of pairing centers in meiosis. J Cell Sci 2011; 124:1955-63. [PMID: 21625006 DOI: 10.1242/jcs.006387] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Homologous pairing establishes the foundation for accurate reductional segregation during meiosis I in sexual organisms. This Commentary summarizes recent progress in our understanding of homologous pairing in meiosis, and will focus on the characteristics and mechanisms of specialized chromosome sites, called pairing centers (PCs), in Caenorhabditis elegans and Drosophila melanogaster. In C. elegans, each chromosome contains a single PC that stabilizes chromosome pairing and initiates synapsis of homologous chromosomes. Specific zinc-finger proteins recruited to PCs link chromosomes to nuclear envelope proteins--and through them to the microtubule cytoskeleton--thereby stimulating chromosome movements in early prophase, which are thought to be important for homolog sorting. This mechanism appears to be a variant of the 'telomere bouquet' process, in which telomeres cluster on the nuclear envelope, connect chromosomes through nuclear envelope proteins to the cytoskeleton and lead chromosome movements that promote homologous synapsis. In Drosophila males, which undergo meiosis without recombination, pairing of the largely non-homologous X and Y chromosomes occurs at specific repetitive sequences in the ribosomal DNA. Although no other clear examples of PC-based pairing mechanisms have been described, there is evidence for special roles of telomeres and centromeres in aspects of chromosome pairing, synapsis and segregation; these roles are in some cases similar to those of PCs.
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Affiliation(s)
- Jui-He Tsai
- Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
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