1
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Marshall WF, Fung JC. Modeling homologous chromosome recognition via nonspecific interactions. Proc Natl Acad Sci U S A 2024; 121:e2317373121. [PMID: 38722810 PMCID: PMC11098084 DOI: 10.1073/pnas.2317373121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 03/18/2024] [Indexed: 05/18/2024] Open
Abstract
In many organisms, most notably Drosophila, homologous chromosomes associate in somatic cells, a phenomenon known as somatic pairing, which takes place without double strand breaks or strand invasion, thus requiring some other mechanism for homologs to recognize each other. Several studies have suggested a "specific button" model, in which a series of distinct regions in the genome, known as buttons, can associate with each other, mediated by different proteins that bind to these different regions. Here, we use computational modeling to evaluate an alternative "button barcode" model, in which there is only one type of recognition site or adhesion button, present in many copies in the genome, each of which can associate with any of the others with equal affinity. In this model, buttons are nonuniformly distributed, such that alignment of a chromosome with its correct homolog, compared with a nonhomolog, is energetically favored; since to achieve nonhomologous alignment, chromosomes would be required to mechanically deform in order to bring their buttons into mutual register. By simulating randomly generated nonuniform button distributions, many highly effective button barcodes can be easily found, some of which achieve virtually perfect pairing fidelity. This model is consistent with existing literature on the effect of translocations of different sizes on homolog pairing. We conclude that a button barcode model can attain highly specific homolog recognition, comparable to that seen in actual cells undergoing somatic homolog pairing, without the need for specific interactions. This model may have implications for how meiotic pairing is achieved.
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Affiliation(s)
- Wallace F. Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA94158
| | - Jennifer C. Fung
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, CA94158
- Center for Reproductive Sciences, University of California, San Francisco, CA94158
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2
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Chriss A, Börner GV, Ryan SD. Agent-based modeling of nuclear chromosome ensembles identifies determinants of homolog pairing during meiosis. PLoS Comput Biol 2024; 20:e1011416. [PMID: 38739641 PMCID: PMC11115365 DOI: 10.1371/journal.pcbi.1011416] [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: 08/08/2023] [Revised: 05/23/2024] [Accepted: 04/10/2024] [Indexed: 05/16/2024] Open
Abstract
During meiosis, pairing of homologous chromosomes (homologs) ensures the formation of haploid gametes from diploid precursor cells, a prerequisite for sexual reproduction. Pairing during meiotic prophase I facilitates crossover recombination and homolog segregation during the ensuing reductional cell division. Mechanisms that ensure stable homolog alignment in the presence of an excess of non-homologous chromosomes have remained elusive, but rapid chromosome movements appear to play a role in the process. Apart from homolog attraction, provided by early intermediates of homologous recombination, dissociation of non-homologous associations also appears to contribute to homolog pairing, as suggested by the detection of stable non-homologous chromosome associations in pairing-defective mutants. Here, we have developed an agent-based model for homolog pairing derived from the dynamics of a naturally occurring chromosome ensemble. The model simulates unidirectional chromosome movements, as well as collision dynamics determined by attractive and repulsive forces arising from close-range physical interactions. Chromosome number and size as well as movement velocity and repulsive forces are identified as key factors in the kinetics and efficiency of homologous pairing in addition to homolog attraction. Dissociation of interactions between non-homologous chromosomes may contribute to pairing by crowding homologs into a limited nuclear area thus creating preconditions for close-range homolog attraction. Incorporating natural chromosome lengths, the model accurately recapitulates efficiency and kinetics of homolog pairing observed for wild-type and mutant meiosis in budding yeast, and can be adapted to nuclear dimensions and chromosome sets of other organisms.
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Affiliation(s)
- Ariana Chriss
- Department of Mathematics and Statistics, Cleveland State University, Cleveland, Ohio, United States of America
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
| | - G. Valentin Börner
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio, United States of America
- Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, Ohio, United States of America
| | - Shawn D. Ryan
- Department of Mathematics and Statistics, Cleveland State University, Cleveland, Ohio, United States of America
- Center for Applied Data Analysis and Modeling, Cleveland State University, Cleveland, Ohio, United States of America
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3
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Chriss A, Börner GV, Ryan SD. Agent-based modeling of nuclear chromosome ensemble identifies determinants of homolog pairing during meiosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.09.552574. [PMID: 38260664 PMCID: PMC10802385 DOI: 10.1101/2023.08.09.552574] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
During meiosis, pairing of homologous chromosomes (homologs) ensures the formation of haploid gametes from diploid precursor cells, a prerequisite for sexual reproduction. Pairing during meiotic prophase I facilitates crossover recombination and homolog segregation during the ensuing reductional cell division. Mechanisms that ensure stable homolog alignment in the presence of an excess of non-homologous chromosomes have remained elusive, but rapid chromosome movements during prophase I appear to play a role in the process. Apart from homolog attraction, provided by early intermediates of homologous recombination, dissociation of non-homologous associations also appears to contribute to homolog pairing, as suggested by the detection of stable non-homologous chromosome associations in pairing-defective mutants. Here, we have developed an agent-based model for homolog pairing derived from the dynamics of a naturally occurring chromosome ensemble. The model simulates unidirectional chromosome movements, as well as collision dynamics determined by attractive and repulsive forces arising from close-range physical interactions. In addition to homolog attraction, chromosome number and size as well as movement velocity and repulsive forces are identified as key factors in the kinetics and efficiency of homologous pairing. Dissociation of interactions between non-homologous chromosomes may contribute to pairing by crowding homologs into a limited nuclear area thus creating preconditions for close-range homolog attraction. Predictions from the model are readily compared to experimental data from budding yeast, parameters can be adjusted to other cellular systems and predictions from the model can be tested via experimental manipulation of the relevant chromosomal features.
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Affiliation(s)
- Ariana Chriss
- Department of Mathematics and Statistics, Cleveland State University, Cleveland, OH 44115
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH 44115
| | - G. Valentin Börner
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, OH 44115
- Center for Gene Regulation in Health and Disease, Cleveland State University, Cleveland, OH 44115
| | - Shawn D. Ryan
- Department of Mathematics and Statistics, Cleveland State University, Cleveland, OH 44115
- Center for Applied Data Analysis and Modeling, Cleveland State University, Cleveland, OH 44115
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4
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Fernández-Álvarez A. Beyond tradition: exploring the non-canonical functions of telomeres in meiosis. Front Cell Dev Biol 2023; 11:1278571. [PMID: 38020928 PMCID: PMC10679444 DOI: 10.3389/fcell.2023.1278571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/01/2023] [Indexed: 12/01/2023] Open
Abstract
The telomere bouquet is a specific chromosomal configuration that forms during meiosis at the zygotene stage, when telomeres cluster together at the nuclear envelope. This clustering allows cytoskeleton-induced movements to be transmitted to the chromosomes, thereby facilitating homologous chromosome search and pairing. However, loss of the bouquet results in more severe meiotic defects than can be attributed solely to recombination problems, suggesting that the bouquet's full function remains elusive. Despite its transient nature and the challenges in performing in vivo analyses, information is emerging that points to a remarkable suite of non-canonical functions carried out by the bouquet. Here, we describe how new approaches in quantitative cell biology can contribute to establishing the molecular basis of the full function and plasticity of the bouquet, and thus generate a comprehensive picture of the telomeric control of meiosis.
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Affiliation(s)
- Alfonso Fernández-Álvarez
- Institute of Functional Biology and Genomics (IBFG), Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, Salamanca, Spain
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5
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Marshall WF, Fung JC. Homologous chromosome recognition via nonspecific interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.09.544427. [PMID: 37333079 PMCID: PMC10274854 DOI: 10.1101/2023.06.09.544427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
In many organisms, most notably Drosophila, homologous chromosomes in somatic cells associate with each other, a phenomenon known as somatic homolog pairing. Unlike in meiosis, where homology is read out at the level of DNA sequence complementarity, somatic homolog pairing takes place without double strand breaks or strand invasion, thus requiring some other mechanism for homologs to recognize each other. Several studies have suggested a "specific button" model, in which a series of distinct regions in the genome, known as buttons, can associate with each other, presumably mediated by different proteins that bind to these different regions. Here we consider an alternative model, which we term the "button barcode" model, in which there is only one type of recognition site or adhesion button, present in many copies in the genome, each of which can associate with any of the others with equal affinity. An important component of this model is that the buttons are non-uniformly distributed, such that alignment of a chromosome with its correct homolog, compared with a non-homolog, is energetically favored; since to achieve nonhomologous alignment, chromosomes would be required to mechanically deform in order to bring their buttons into mutual register. We investigated several types of barcodes and examined their effect on pairing fidelity. We found that high fidelity homolog recognition can be achieved by arranging chromosome pairing buttons according to an actual industrial barcode used for warehouse sorting. By simulating randomly generated non-uniform button distributions, many highly effective button barcodes can be easily found, some of which achieve virtually perfect pairing fidelity. This model is consistent with existing literature on the effect of translocations of different sizes on homolog pairing. We conclude that a button barcode model can attain highly specific homolog recognition, comparable to that seen in actual cells undergoing somatic homolog pairing, without the need for specific interactions. This model may have implications for how meiotic pairing is achieved.
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6
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Navarro EJ, Marshall WF, Fung JC. Modeling cell biological features of meiotic chromosome pairing to study interlock resolution. PLoS Comput Biol 2022; 18:e1010252. [PMID: 35696428 PMCID: PMC9232156 DOI: 10.1371/journal.pcbi.1010252] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 06/24/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
During meiosis, homologous chromosomes become associated side by side in a process known as homologous chromosome pairing. Pairing requires long range chromosome motion through a nucleus that is full of other chromosomes. It remains unclear how the cell manages to align each pair of chromosomes quickly while mitigating and resolving interlocks. Here, we use a coarse-grained molecular dynamics model to investigate how specific features of meiosis, including motor-driven telomere motion, nuclear envelope interactions, and increased nuclear size, affect the rate of pairing and the mitigation/resolution of interlocks. By creating in silico versions of three yeast strains and comparing the results of our model to experimental data, we find that a more distributed placement of pairing sites along the chromosome is necessary to replicate experimental findings. Active motion of the telomeric ends speeds up pairing only if binding sites are spread along the chromosome length. Adding a meiotic bouquet significantly speeds up pairing but does not significantly change the number of interlocks. An increase in nuclear size slows down pairing while greatly reducing the number of interlocks. Interestingly, active forces increase the number of interlocks, which raises the question: How do these interlocks resolve? Our model gives us detailed movies of interlock resolution events which we then analyze to build a step-by-step recipe for interlock resolution. In our model, interlocks must first translocate to the ends, where they are held in a quasi-stable state by a large number of paired sites on one side. To completely resolve an interlock, the telomeres of the involved chromosomes must come in close proximity so that the cooperativity of pairing coupled with random motion causes the telomeres to unwind. Together our results indicate that computational modeling of homolog pairing provides insight into the specific cell biological changes that occur during meiosis.
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Affiliation(s)
- Erik J. Navarro
- Department of Obstetrics, Gynecology and Reproductive Sciences and Center of Reproductive Sciences, University of California, San Francisco, California, United States of America
| | - Wallace F. Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Jennifer C. Fung
- Department of Obstetrics, Gynecology and Reproductive Sciences and Center of Reproductive Sciences, University of California, San Francisco, California, United States of America
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7
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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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8
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Child MB, Bateman JR, Jahangiri A, Reimer A, Lammers NC, Sabouni N, Villamarin D, McKenzie-Smith GC, Johnson JE, Jost D, Garcia HG. Live imaging and biophysical modeling support a button-based mechanism of somatic homolog pairing in Drosophila. eLife 2021; 10:64412. [PMID: 34100718 PMCID: PMC8294847 DOI: 10.7554/elife.64412] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 06/07/2021] [Indexed: 12/22/2022] Open
Abstract
Three-dimensional eukaryotic genome organization provides the structural basis for gene regulation. In Drosophila melanogaster, genome folding is characterized by somatic homolog pairing, where homologous chromosomes are intimately paired from end to end; however, how homologs identify one another and pair has remained mysterious. Recently, this process has been proposed to be driven by specifically interacting 'buttons' encoded along chromosomes. Here, we turned this hypothesis into a quantitative biophysical model to demonstrate that a button-based mechanism can lead to chromosome-wide pairing. We tested our model using live-imaging measurements of chromosomal loci tagged with the MS2 and PP7 nascent RNA labeling systems. We show solid agreement between model predictions and experiments in the pairing dynamics of individual homologous loci. Our results strongly support a button-based mechanism of somatic homolog pairing in Drosophila and provide a theoretical framework for revealing the molecular identity and regulation of buttons.
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Affiliation(s)
- Myron Barber Child
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States
| | - Jack R Bateman
- Biology Department, Bowdoin College, Brunswick, United States
| | - Amir Jahangiri
- Univ Grenoble Alpes CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France
| | - Armando Reimer
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States
| | - Nicholas C Lammers
- Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States
| | - Nica Sabouni
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | | | | | | | - Daniel Jost
- Univ Grenoble Alpes CNRS, Grenoble INP, TIMC-IMAG, Grenoble, France.,Université de Lyon, ENS de Lyon, Univ Claude Bernard, CNRS, Laboratory of Biology and Modeling of the Cell, Lyon, France
| | - Hernan G Garcia
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Physics, University of California, Berkeley, Berkeley, United States.,Biophysics Graduate Group, University of California, Berkeley, Berkeley, United States.,Institute for Quantitative Biosciences-QB3, University of California, Berkeley, Berkeley, United States
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9
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Zhang J, Feng C, Su H, Liu Y, Liu Y, Han F. The Cohesin Complex Subunit ZmSMC3 Participates in Meiotic Centromere Pairing in Maize. THE PLANT CELL 2020; 32:1323-1336. [PMID: 31996400 PMCID: PMC7145474 DOI: 10.1105/tpc.19.00834] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/09/2020] [Accepted: 01/27/2020] [Indexed: 05/25/2023]
Abstract
Meiosis consists of two highly conserved nuclear divisions, which allow eukaryotes to maintain their chromosome number through sexual reproduction. The successful completion of meiosis depends on homologous chromosome pairing. Centromere interactions during early meiotic prophase I facilitate homologous chromosome pairing, but the underlying mechanism is unclear. Here, we performed chromatin immunoprecipitation-mass spectrometry analysis of maize (Zea mays) anthers during early meiotic prophase I using anti-centromeric histone H3 (CENH3) antibodies and determined that the cohesin subunit Structural Maintenance of Chromosome3 (SMC3) interacts with CENH3 during this period. SMC3 is enriched at centromeres and along chromosome arms in threads from leptotene to pachytene and might promote interactions between homologous centromeres. We observed dysfunctional SMC3 assembly in meiotic-specific maize mutants with defective centromere pairing. In SMC3 RNAi meiocytes, centromere pairing defects were observed during early meiotic prophase I, SMC3 was weakly associated with centromeres, and SMC3 did not localize to the chromosome arms. In wild-type mitosis, SMC3 is associated with chromatin and is enriched at centromeres from prophase to anaphase. CRISPR-Cas9-induced Zmsmc3 mutants showed premature loss of sister chromatid cohesion and mis-segregation of chromosomes in mitotic spreads. Our findings suggest that in addition to sister chromatid cohesion, ZmSMC3 participates in meiotic centromere pairing.
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Affiliation(s)
- Jing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chao Feng
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Handong Su
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yang Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yalin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, 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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10
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Zhang J, Han F. Centromere pairing precedes meiotic chromosome pairing in plants. SCIENCE CHINA. LIFE SCIENCES 2017; 60:1197-1202. [PMID: 28755295 DOI: 10.1007/s11427-017-9109-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 06/02/2017] [Indexed: 10/19/2022]
Abstract
Meiosis is a specialized eukaryotic cell division, in which diploid cells undergo a single round of DNA replication and two rounds of nuclear division to produce haploid gametes. In most eukaryotes, the core events of meiotic prophase I are chromosomal pairing, synapsis and recombination. To ensure accurate chromosomal segregation, homologs have to identify and align along each other at the onset of meiosis. Although much progress has been made in elucidating meiotic processes, information on the mechanisms underlying chromosome pairing is limited in contrast to the meiotic recombination and synapsis events. Recent research in many organisms indicated that centromere interactions during early meiotic prophase facilitate homologous chromosome pairing, and functional centromere is a prerequisite for centromere pairing such as in maize. Here, we summarize the recent achievements of chromosome pairing research on plants and other organisms, and outline centromere interactions, nuclear chromosome orientation, and meiotic cohesin, as main determinants of chromosome pairing in early meiotic prophase.
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Affiliation(s)
- Jing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
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11
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Lefrançois P, Rockmill B, Xie P, Roeder GS, Snyder M. Multiple Pairwise Analysis of Non-homologous Centromere Coupling Reveals Preferential Chromosome Size-Dependent Interactions and a Role for Bouquet Formation in Establishing the Interaction Pattern. PLoS Genet 2016; 12:e1006347. [PMID: 27768699 PMCID: PMC5074576 DOI: 10.1371/journal.pgen.1006347] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 09/07/2016] [Indexed: 12/26/2022] Open
Abstract
During meiosis, chromosomes undergo a homology search in order to locate their homolog to form stable pairs and exchange genetic material. Early in prophase, chromosomes associate in mostly non-homologous pairs, tethered only at their centromeres. This phenomenon, conserved through higher eukaryotes, is termed centromere coupling in budding yeast. Both initiation of recombination and the presence of homologs are dispensable for centromere coupling (occurring in spo11 mutants and haploids induced to undergo meiosis) but the presence of the synaptonemal complex (SC) protein Zip1 is required. The nature and mechanism of coupling have yet to be elucidated. Here we present the first pairwise analysis of centromere coupling in an effort to uncover underlying rules that may exist within these non-homologous interactions. We designed a novel chromosome conformation capture (3C)-based assay to detect all possible interactions between non-homologous yeast centromeres during early meiosis. Using this variant of 3C-qPCR, we found a size-dependent interaction pattern, in which chromosomes assort preferentially with chromosomes of similar sizes, in haploid and diploid spo11 cells, but not in a coupling-defective mutant (spo11 zip1 haploid and diploid yeast). This pattern is also observed in wild-type diploids early in meiosis but disappears as meiosis progresses and homologous chromosomes pair. We found no evidence to support the notion that ancestral centromere homology plays a role in pattern establishment in S. cerevisiae post-genome duplication. Moreover, we found a role for the meiotic bouquet in establishing the size dependence of centromere coupling, as abolishing bouquet (using the bouquet-defective spo11 ndj1 mutant) reduces it. Coupling in spo11 ndj1 rather follows telomere clustering preferences. We propose that a chromosome size preference for centromere coupling helps establish efficient homolog recognition.
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Affiliation(s)
- Philippe Lefrançois
- Department of Molecular, Cellular and Developmental Biology Yale University New Haven, United States of America
- Faculty of Medicine University of Montreal, Montreal, CANADA
- * E-mail: (PL); (MS)
| | - Beth Rockmill
- Department of Molecular, Cellular and Developmental Biology Yale University New Haven, United States of America
- Department of Molecular and Cell Biology University of California Berkeley, Berkeley, United States of America
| | - Pingxing Xie
- Faculty of Medicine McGill University Montreal, CANADA
| | - G. Shirleen Roeder
- Department of Molecular, Cellular and Developmental Biology Yale University New Haven, United States of America
| | - Michael Snyder
- Department of Genetics Stanford University School of Medicine Stanford, United States of America
- * E-mail: (PL); (MS)
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12
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Marshall WF, Fung JC. Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion. Phys Biol 2016; 13:026003. [PMID: 27046097 DOI: 10.1088/1478-3975/13/2/026003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The recognition and pairing of homologous chromosomes during meiosis is a complex physical and molecular process involving a combination of polymer dynamics and molecular recognition events. Two highly conserved features of meiotic chromosome behavior are the attachment of telomeres to the nuclear envelope and the active random motion of telomeres driven by their interaction with cytoskeletal motor proteins. Both of these features have been proposed to facilitate the process of homolog pairing, but exactly what role these features play in meiosis remains poorly understood. Here we investigate the roles of active motion and nuclear envelope tethering using a Brownian dynamics simulation in which meiotic chromosomes are represented by a Rouse polymer model subjected to tethering and active forces at the telomeres. We find that tethering telomeres to the nuclear envelope slows down pairing relative to the rates achieved by unattached chromosomes, but that randomly directed active forces applied to the telomeres speed up pairing dramatically in a manner that depends on the statistical properties of the telomere force fluctuations. The increased rate of initial pairing cannot be explained by stretching out of the chromosome conformation but instead seems to correlate with anomalous diffusion of sub-telomeric regions.
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Affiliation(s)
- Wallace F Marshall
- Department of Biochemistry and Biophysics, University of California San Francisco, USA
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13
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Calderón MDC, Rey MD, Cabrera A, Prieto P. The subtelomeric region is important for chromosome recognition and pairing during meiosis. Sci Rep 2014; 4:6488. [PMID: 25270583 PMCID: PMC4180820 DOI: 10.1038/srep06488] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/10/2014] [Indexed: 12/26/2022] Open
Abstract
The process of meiosis results in the formation of haploid daughter cells, each of which inherit a half of the diploid parental cells' genetic material. The ordered association of homologues (identical chromosomes) is a critical prerequisite for a successful outcome of meiosis. Homologue recognition and pairing are initiated at the chromosome ends, which comprise the telomere dominated by generic repetitive sequences, and the adjacent subtelomeric region, which harbours chromosome-specific sequences. In many organisms telomeres are responsible for bringing the ends of the chromosomes close together during early meiosis, but little is known regarding the role of the subtelomeric region sequence during meiosis. Here, the observation of homologue pairing between a pair of Hordeum chilense chromosomes lacking the subtelomeric region on one chromosome arm indicates that the subtelomeric region is important for the process of homologous chromosome recognition and pairing.
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Affiliation(s)
- María del Carmen Calderón
- Plant Breeding Department, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Apartado 4084, E-14080 Córdoba, Spain
| | - María-Dolores Rey
- Plant Breeding Department, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Apartado 4084, E-14080 Córdoba, Spain
| | - Adoración Cabrera
- Department of Genetics, ETSIAM, University of Córdoba, Campus de Excelencia Internacional Agroalimentario, CeiA3, 14071 Córdoba, Spain
| | - Pilar Prieto
- Plant Breeding Department, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Apartado 4084, E-14080 Córdoba, Spain
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14
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Zhang J, Zhang B, Su H, Birchler JA, Han F. Molecular mechanisms of homologous chromosome pairing and segregation in plants. J Genet Genomics 2014; 41:117-23. [PMID: 24656232 DOI: 10.1016/j.jgg.2013.12.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/09/2013] [Accepted: 12/09/2013] [Indexed: 11/18/2022]
Abstract
In most eukaryotic species, three basic steps of pairing, recombination and synapsis occur during prophase of meiosis I. Homologous chromosomal pairing and recombination are essential for accurate segregation of chromosomes. In contrast to the well-studied processes such as recombination and synapsis, many aspects of chromosome pairing are still obscure. Recent progress in several species indicates that the telomere bouquet formation can facilitate homologous chromosome pairing by bringing chromosome ends into close proximity, but the sole presence of telomere clustering is not sufficient for recognizing homologous pairs. On the other hand, accurate segregation of the genetic material from parent to offspring during meiosis is dependent on the segregation of homologs in the reductional meiotic division (MI) with sister kinetochores exhibiting mono-orientation from the same pole, and the segregation of sister chromatids during the equational meiotic division (MII) with kinetochores showing bi-orientation from the two poles. The underlying mechanism of orientation and segregation is still unclear. Here we focus on recent studies in plants and other species that provide insight into how chromosomes find their partners and mechanisms mediating chromosomal segregation.
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Affiliation(s)
- Jing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Handong Su
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - James A Birchler
- Division of Biological Sciences, 311 Tucker Hall, University of Missouri, Columbia, MO 65211, USA.
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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Zhang J, Pawlowski WP, Han F. Centromere pairing in early meiotic prophase requires active centromeres and precedes installation of the synaptonemal complex in maize. THE PLANT CELL 2013; 25:3900-9. [PMID: 24143803 PMCID: PMC3877799 DOI: 10.1105/tpc.113.117846] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 09/20/2013] [Accepted: 09/27/2013] [Indexed: 05/19/2023]
Abstract
Pairing of homologous chromosomes in meiosis is critical for their segregation to daughter cells. In most eukaryotes, clustering of telomeres precedes and facilitates chromosome pairing. In several species, centromeres also form pairwise associations, known as coupling, before the onset of pairing. We found that, in maize (Zea mays), centromere association begins at the leptotene stage and occurs earlier than the formation of the telomere bouquet. We established that centromere pairing requires centromere activity and the sole presence of centromeric repeats is not sufficient for pairing. In several species, homologs of the ZIP1 protein, which forms the central element of the synaptonemal complex in budding yeast (Saccharomyces cerevisiae), play essential roles in centromere coupling. However, we found that the maize ZIP1 homolog ZYP1 installs in the centromeric regions of chromosomes after centromeres form associations. Instead, we found that maize structural maintenance of chromosomes6 homolog forms a central element of the synaptonemal complex, which is required for centromere associations. These data shed light on the poorly understood mechanism of centromere interactions and suggest that this mechanism may vary somewhat in different species.
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Affiliation(s)
- Jing Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Wojciech P. Pawlowski
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, New York 14853
| | - Fangpu Han
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Address correspondence to
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16
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Richards DM, Greer E, Martin AC, Moore G, Shaw PJ, Howard M. Quantitative dynamics of telomere bouquet formation. PLoS Comput Biol 2012; 8:e1002812. [PMID: 23236272 PMCID: PMC3516562 DOI: 10.1371/journal.pcbi.1002812] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 10/18/2012] [Indexed: 11/19/2022] Open
Abstract
The mechanism by which homologous chromosomes pair during meiosis, as a prelude to recombination, has long been mysterious. At meiosis, the telomeres in many organisms attach to the nuclear envelope and move together to form the telomere bouquet, perhaps to facilitate the homologous search. It is believed that diffusion alone is not sufficient to account for the formation of the bouquet, and that some directed movement is also required. Here we consider the formation of the telomere bouquet in a wheat-rye hybrid both experimentally and using mathematical modelling. The large size of the wheat nucleus and wheat's commercial importance make chromosomal pairing in wheat a particularly interesting and important process, which may well shed light on pairing in other organisms. We show that, prior to bouquet formation, sister chromatid telomeres are always attached to a hemisphere of the nuclear membrane and tend to associate in pairs. We study a mutant lacking the Ph1 locus, a locus ensuring correct homologous chromosome pairing, and discover that bouquet formation is delayed in the wild type compared to the mutant. Further, we develop a mathematical model of bouquet formation involving diffusion and directed movement, where we show that directed movement alone is sufficient to explain bouquet formation dynamics. The appearance of sexual reproduction over a billion years ago led to a revolution in how organisms pass on genetic material to their offspring. In sexually reproducing organisms parental diploid cells, containing two nearly identical copies of each chromosome (homologues), produce gametes containing only one copy of each chromosome. This in turn requires the pairing of the related homologous chromosomes to ensure their subsequent segregation into the gametes. How this pairing is achieved is poorly understood since chromosomes must search the entire nucleus for their homologous partner. Many organisms move the ends of each chromosome (the telomeres) along the periphery of the nucleus into a small patch forming the telomere bouquet. We show here that direct movement of telomeres towards the bouquet site, potentially driven by molecular motors, can explain bouquet formation dynamics. We focus in particular on a wheat-rye hybrid since understanding homologous pairing in wheat could have profound implications for breeding resistant crops by aiding the production of hybrids. We also show that wheat seems to have evolved a mechanism to delay the onset of telomere bouquet formation, perhaps in order to ensure chromosomes find their correct homologous partners.
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Affiliation(s)
- David M. Richards
- Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
| | - Emma Greer
- Cell & Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
| | - Azahara C. Martin
- Cell & Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
| | - Graham Moore
- Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
| | - Peter J. Shaw
- Cell & Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
- * E-mail: (PJS); (MH)
| | - Martin Howard
- Computational and Systems Biology, John Innes Centre, Norwich Research Park, Norwich, Norfolk, United Kingdom
- * E-mail: (PJS); (MH)
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17
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Loidl J, Lukaszewicz A, Howard-Till RA, Koestler T. The Tetrahymena meiotic chromosome bouquet is organized by centromeres and promotes interhomolog recombination. J Cell Sci 2012; 125:5873-80. [PMID: 22976299 DOI: 10.1242/jcs.112664] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to form crossovers and to undergo reductional segregation during meiosis, homologous chromosomes must pair. In Tetrahymena, meiotic prophase nuclei elongate immensely, and, within the elongated nucleus, chromosomes are arranged with telomeres assembled at one pole and centromeres at the opposite pole. This organisation is an exaggerated form of the bouquet, a meiotic chromosome arrangement that is widely conserved among eukaryotes. We show that centromere function is crucial for the formation of Tetrahymena's stretched bouquet and, thereby, for homologue pairing. This finding adds to previous reports of the importance of centromeres in chromosome pairing in budding yeast and in Drosophila. Tetrahymena's bouquet is an ataxia telangiectasia- and RAD3-related (ATR)-dependent meiotic DNA damage response that is triggered by meiotic DNA double-strand breaks (DSBs), suggesting that the bouquet is needed for DSB repair. However, in the present study we show that although homologous pairing is impeded in the absence of the bouquet, DSB repair takes place nevertheless. Moreover, recombinational DSB repair, as monitored by bromodeoxyuridine incorporation, takes place only after exit from the bouquet stage. Therefore, we conclude that the bouquet is not required for DSB repair per se, but may be necessary for the alignment of homologous loci in order to promote homologous crossovers over alternative repair pathways.
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Affiliation(s)
- Josef Loidl
- Department of Chromosome Biology and Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, A-1030 Vienna, Austria
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Centromeres cluster de novo at the beginning of meiosis in Brachypodium distachyon. PLoS One 2012; 7:e44681. [PMID: 22970287 PMCID: PMC3436855 DOI: 10.1371/journal.pone.0044681] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 08/07/2012] [Indexed: 01/01/2023] Open
Abstract
In most eukaryotes that have been studied, the telomeres cluster into a bouquet early in meiosis, and in wheat and its relatives and in Arabidopsis the centromeres pair at the same time. In Arabidopsis, the telomeres do not cluster as a typical telomere bouquet on the nuclear membrane but are associated with the nucleolus both somatically and at the onset of meiosis. We therefore assessed whether Brachypodium distachyon, a monocot species related to cereals and whose genome is approximately twice the size of Arabidopsis thaliana, also exhibited an atypical telomere bouquet and centromere pairing. In order to investigate the occurrence of a bouquet and centromere pairing in B distachyon, we first had to establish protocols for studying meiosis in this species. This enabled us to visualize chromosome behaviour in meiocytes derived from young B distachyon spikelets in three-dimensions by fluorescent in situ hybridization (FISH), and accurately to stage meiosis based on chromatin morphology in relation to spikelet size and the timing of sample collection. Surprisingly, this study revealed that the centromeres clustered as a single site at the same time as the telomeres also formed a bouquet or single cluster.
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