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Park J, Jeon H, Hwangbo A, Min K, Ko J, Kim JE, Kim S, Shin JY, Lee YH, Lee YW, Son H. A winged-helix DNA-binding protein is essential for self-fertility during sexual development of the homothallic fungus Fusarium graminearum. mSphere 2024; 9:e0051124. [PMID: 39189781 PMCID: PMC11423578 DOI: 10.1128/msphere.00511-24] [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: 06/15/2024] [Accepted: 07/19/2024] [Indexed: 08/28/2024] Open
Abstract
Sexual reproduction is crucial for increasing the genetic diversity of populations and providing overwintering structures, such as perithecia and associated tissue, in the destructive plant pathogenic fungus Fusarium graminearum. While mating-type genes serve as master regulators in fungal sexual reproduction, the molecular mechanisms underlying this process remain elusive. Winged-helix DNA-binding proteins are key regulators of embryogenesis and cell differentiation in higher eukaryotes. These proteins are implicated in the morphogenesis and development of several fungal species. However, their involvement in sexual reproduction remains largely unexplored in F. graminearum. Here, we investigated the function of winged-helix DNA-binding proteins in vegetative growth, conidiation, and sexual reproduction, with a specific focus on the FgWING27, which is highly conserved among Fusarium species. Deletion of FgWING27 resulted in an abnormal pattern characterized by a gradual increase in the expression of mating-type genes during sexual development, indicating its crucial role in the stage-specific genetic regulation of MAT genes in the late stages of sexual development. Furthermore, using chromatin immunoprecipitation followed by sequencing analysis, we identified Fg17056 as a downstream gene of Fgwing27, which is essential for sexual reproduction. These findings underscore the significance of winged-helix DNA-binding proteins in fungal development and reproduction in F. graminearum, and highlight the pivotal role of Fgwing27 as a core genetic factor in the intricate genetic regulatory network governing sexual reproduction.IMPORTANCEFusarium graminearum is a devastating plant pathogenic fungus causing significant economic losses due to reduced crop yields. In Fusarium Head Blight epidemics, spores produced through sexual and asexual reproduction serve as inoculum, making it essential to understand the fungal reproduction process. Here, we focus on winged-helix DNA-binding proteins, which have been reported to play crucial roles in cell cycle regulation and differentiation, and address their requirement in the sexual reproduction of F. graminearum. Furthermore, we identified a highly conserved protein in Fusarium as a key factor in self-fertility, along with the discovery of its direct downstream genes. This provides crucial information for constructing the complex genetic regulatory network of sexual reproduction and significantly contribute to further research on sexual reproduction in Fusarium species.
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Affiliation(s)
- Jiyeun Park
- Institute for Plant Sciences, University of Cologne, Cologne, Germany
| | - Hosung Jeon
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Aram Hwangbo
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Kyunghun Min
- Department of Plant Science, Gangneung-Wonju National University, Gangneung, South Korea
| | - Jaeho Ko
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Jung-Eun Kim
- Research Institute of Climate Change and Agriculture, National Institute of Horticultural and Herbal Science, Jeju, South Korea
| | - Sieun Kim
- Horticultural and Herbal Crop Environment Division, National Institute of Horticultural and Herbal Science, Wanju, South Korea
| | - Ji Young Shin
- Honam National Institute of Biological Resources, Mokpo, South Korea
| | - Yong-Hwan Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
- Interdisciplinary Programs in Agricultural Genomics, Seoul National University, Seoul, South Korea
- Center for Plant Microbiome Research, Seoul National University, Seoul, South Korea
- Plant Immunity Research Center, Seoul National University, Seoul, South Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, South Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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2
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Mazur AK, Gladyshev E. C-DNA may facilitate homologous DNA pairing. Trends Genet 2023:S0168-9525(23)00023-9. [PMID: 36804168 DOI: 10.1016/j.tig.2023.01.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 01/23/2023] [Accepted: 01/30/2023] [Indexed: 02/17/2023]
Abstract
Recombination-independent homologous pairing represents a prominent yet largely enigmatic feature of chromosome biology. As suggested by studies in the fungus Neurospora crassa, this process may be based on the direct pairing of homologous DNA molecules. Theoretical search for the DNA structures consistent with those genetic results has led to an all-atom model in which the B-DNA conformation of the paired double helices is strongly shifted toward C-DNA. Coincidentally, C-DNA also features a very shallow major groove that could permit initial homologous contacts without atom-atom clashes. The hereby conjectured role of C-DNA in homologous pairing should encourage the efforts to discover its biological functions and may also clarify the mechanism of recombination-independent recognition of DNA homology.
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Affiliation(s)
- Alexey K Mazur
- CNRS, Université Paris Cité, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, Paris, France; Institut Pasteur, Université Paris Cité, Group Fungal Epigenomics, Paris, France.
| | - Eugene Gladyshev
- Institut Pasteur, Université Paris Cité, Group Fungal Epigenomics, Paris, France.
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3
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Chuang YC, Smith GR. Dynamic configurations of meiotic DNA-break hotspot determinant proteins. J Cell Sci 2022; 135:jcs259061. [PMID: 35028663 PMCID: PMC8918816 DOI: 10.1242/jcs.259061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 12/29/2021] [Indexed: 11/20/2022] Open
Abstract
Appropriate DNA double-strand break (DSB) and crossover distributions are required for proper meiotic chromosome segregation. Schizosaccharomyces pombe linear element proteins (LinEs) determine DSB hotspots; LinE-bound hotspots form three-dimensional clusters over ∼200 kb chromosomal regions. Here, we investigated LinE configurations and distributions in live cells using super-resolution fluorescence microscopy. We found LinEs form two chromosomal structures, dot-like and linear structures, in both zygotic and azygotic meiosis. Dot-like LinE structures appeared around the time of meiotic DNA replication, underwent dotty-to-linear-to-dotty configurational transitions and disassembled before the first meiotic division. DSB formation and repair did not detectably influence LinE structure formation but failure of DSB formation delayed disassembly. Recombination-deficient LinE missense mutants formed dot-like, but not linear, LinE structures. Our quantitative study reveals a transient form of LinE structures and suggests a novel role for LinE proteins in regulating meiotic events, such as DSB repair. We discuss the relationship of LinEs and the synaptonemal complex in other species. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | - Gerald R. Smith
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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4
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Recombination-independent recognition of DNA homology for meiotic silencing in Neurospora crassa. Proc Natl Acad Sci U S A 2021; 118:2108664118. [PMID: 34385329 DOI: 10.1073/pnas.2108664118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The pairing of homologous chromosomes represents a critical step of meiosis in nearly all sexually reproducing species. In many organisms, pairing involves chromosomes that remain apparently intact. The mechanistic nature of homology recognition at the basis of such pairing is unknown. Using "meiotic silencing by unpaired DNA" (MSUD) as a model process, we demonstrate the existence of a cardinally different approach to DNA homology recognition in meiosis. The main advantage of MSUD over other experimental systems lies in its ability to identify any relatively short DNA fragment lacking a homologous allelic partner. Here, we show that MSUD does not rely on the canonical mechanism of meiotic recombination, yet it is promoted by REC8, a conserved component of the meiotic cohesion complex. We also show that certain patterns of interspersed homology are recognized as pairable during MSUD. Such patterns need to be colinear and must contain short tracts of sequence identity spaced apart at 21 or 22 base pairs. By using these periodicity values as a guiding parameter in all-atom molecular modeling, we discover that homologous DNA molecules can pair by forming quadruplex-based contacts with an interval of 2.5 helical turns. This process requires right-handed plectonemic coiling and additional conformational changes in the intervening double-helical segments. Our results 1) reconcile genetic and biophysical evidence for the existence of direct homologous double-stranded DNA (dsDNA)-dsDNA pairing, 2) identify a role for this process in initiating RNA interference, and 3) suggest that chromosomes can be cross-matched by a precise mechanism that operates on intact dsDNA molecules.
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5
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Mazur AK, Nguyen TS, Gladyshev E. Direct Homologous dsDNA-dsDNA Pairing: How, Where, and Why? J Mol Biol 2019; 432:737-744. [PMID: 31726060 DOI: 10.1016/j.jmb.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/22/2019] [Accepted: 11/05/2019] [Indexed: 10/25/2022]
Abstract
The ability of homologous chromosomes (or selected chromosomal loci) to pair specifically in the apparent absence of DNA breakage and recombination represents a prominent feature of eukaryotic biology. The mechanism of homology recognition at the basis of such recombination-independent pairing has remained elusive. A number of studies have supported the idea that sequence homology can be sensed between intact DNA double helices in vivo. In particular, recent analyses of the two silencing phenomena in fungi, known as "repeat-induced point mutation" (RIP) and "meiotic silencing by unpaired DNA" (MSUD), have provided genetic evidence for the existence of the direct homologous dsDNA-dsDNA pairing. Both RIP and MSUD likely rely on the same search strategy, by which dsDNA segments are matched as arrays of interspersed base-pair triplets. This process is general and very efficient, yet it proceeds normally without the RecA/Rad51/Dmc1 proteins. Further studies of RIP and MSUD may yield surprising insights into the function of DNA in the cell.
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Affiliation(s)
- Alexey K Mazur
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 Rue Pierre et Marie Curie, F-75005 Paris, France; Group Fungal Epigenomics, Department of Mycology, Institut Pasteur, Paris 75015, France; Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Tinh-Suong Nguyen
- Group Fungal Epigenomics, Department of Mycology, Institut Pasteur, Paris 75015, France
| | - Eugene Gladyshev
- Group Fungal Epigenomics, Department of Mycology, Institut Pasteur, Paris 75015, France.
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6
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Repair of exogenous DNA double-strand breaks promotes chromosome synapsis in SPO11-mutant mouse meiocytes, and is altered in the absence of HORMAD1. DNA Repair (Amst) 2018; 63:25-38. [PMID: 29414051 DOI: 10.1016/j.dnarep.2018.01.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 11/22/2022]
Abstract
Repair of SPO11-dependent DNA double-strand breaks (DSBs) via homologous recombination (HR) is essential for stable homologous chromosome pairing and synapsis during meiotic prophase. Here, we induced radiation-induced DSBs to study meiotic recombination and homologous chromosome pairing in mouse meiocytes in the absence of SPO11 activity (Spo11YF/YF model), and in the absence of both SPO11 and HORMAD1 (Spo11/Hormad1 dko). Within 30 min after 5 Gy irradiation of Spo11YF/YF mice, 140-160 DSB repair foci were detected, which specifically localized to the synaptonemal complex axes. Repair of radiation-induced DSBs was incomplete in Spo11YF/YF compared to Spo11+/YF meiocytes. Still, repair of exogenous DSBs promoted partial recovery of chromosome pairing and synapsis in Spo11YF/YF meiocytes. This indicates that at least part of the exogenous DSBs can be processed in an interhomolog recombination repair pathway. Interestingly, in a seperate experiment, using 3 Gy of irradiation, we observed that Spo11/Hormad1 dko spermatocytes contained fewer remaining DSB repair foci at 48 h after irradiation compared to irradiated Spo11 knockout spermatocytes. Together, these results show that recruitment of exogenous DSBs to the synaptonemal complex, in conjunction with repair of exogenous DSBs via the homologous chromosome, contributes to homology recognition. In addition, the data suggest a role for HORMAD1 in DNA repair pathway choice in mouse meiocytes.
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7
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Bowring FJ, Yeadon PJ, Catcheside DEA. Fluorescent Protein as a Tool for Investigating Meiotic Recombination in Neurospora. Methods Mol Biol 2017; 1471:133-145. [PMID: 28349393 DOI: 10.1007/978-1-4939-6340-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have built a series of Neurospora crassa strains containing alleles of green fluorescent protein (GFP) to provide a visual phenotype for investigating meiotic recombination. These strains provide a convenient means of screening the Neurospora knockout library for genes involved in genetic recombination. They permit rapid analysis of recombination outcomes by allowing visualization of segregation patterns in a large number of octads from crosses heterozygous for GFP. Using this system the effect of a knockout on gene conversion and/or on crossing over between the fluorescent marker and the centromere can be measured.
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Affiliation(s)
- Frederick J Bowring
- School of Biological Sciences, Flinders University, 2100, Adelaide, 5001, SA, Australia
| | - P Jane Yeadon
- School of Biological Sciences, Flinders University, 2100, Adelaide, 5001, SA, Australia
| | - David E A Catcheside
- School of Biological Sciences, Flinders University, 2100, Adelaide, 5001, SA, Australia.
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8
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Medhi D, Goldman AS, Lichten M. Local chromosome context is a major determinant of crossover pathway biochemistry during budding yeast meiosis. eLife 2016; 5. [PMID: 27855779 PMCID: PMC5222560 DOI: 10.7554/elife.19669] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/17/2016] [Indexed: 12/20/2022] Open
Abstract
The budding yeast genome contains regions where meiotic recombination initiates more frequently than in others. This pattern parallels enrichment for the meiotic chromosome axis proteins Hop1 and Red1. These proteins are important for Spo11-catalyzed double strand break formation; their contribution to crossover recombination remains undefined. Using the sequence-specific VMA1-derived endonuclease (VDE) to initiate recombination in meiosis, we show that chromosome structure influences the choice of proteins that resolve recombination intermediates to form crossovers. At a Hop1-enriched locus, most VDE-initiated crossovers, like most Spo11-initiated crossovers, required the meiosis-specific MutLγ resolvase. In contrast, at a locus with lower Hop1 occupancy, most VDE-initiated crossovers were MutLγ-independent. In pch2 mutants, the two loci displayed similar Hop1 occupancy levels, and VDE-induced crossovers were similarly MutLγ-dependent. We suggest that meiotic and mitotic recombination pathways coexist within meiotic cells, and that features of meiotic chromosome structure determine whether one or the other predominates in different regions. DOI:http://dx.doi.org/10.7554/eLife.19669.001 Inside the cells of many species, double-stranded DNA is packaged together with specialized proteins to form structures called chromosomes. Breaks that span across both strands of the DNA can cause cell death because if the break is incorrectly repaired, a segment of the DNA may be lost. Cells use a process known as homologous recombination to repair such breaks correctly. This uses an undamaged DNA molecule as a template that can be copied to replace missing segments of the DNA sequence. During the repair of double-strand breaks, connections called crossovers may form. This results in the damaged and undamaged DNA molecules swapping a portion of their sequences. In meiosis, a type of cell division that produces sperm and eggs, cells deliberately break their chromosomes and then repair them using homologous recombination. The crossovers that form during this process are important for sharing chromosomes between the newly forming cells. It is crucial that the crossovers form at the right time and place along the chromosomes. Chromosomes have different structures depending on whether a cell is undergoing meiosis or normal (mitotic) cell division. This structure may influence how and where crossovers form. Enzymes called resolvases catalyze the reactions that occur during the last step in homologous recombination to generate crossovers. One particular resolvase acts only during meiosis, whereas others are active in both mitotic and meiotic cells. However, it is not known whether local features of the chromosome structure – such as the proteins packaged in the chromosome alongside the DNA – influence when and where meiotic crossover occurs. Medhi et al. have now studied how recombination occurs along different regions of the chromosomes in budding yeast cells, which undergo meiosis in a similar way to human cells. The results of the experiments reveal that the mechanism by which crossovers form depends on proteins called axis proteins, one type of which is specifically found in meiotic chromosomes. In regions that had high levels of meiotic axis proteins, crossovers mainly formed using the meiosis-specific resolvase enzyme. In regions that had low levels of meiotic axis proteins, crossovers formed using resolvases that are active in mitotic cells. Further experiments demonstrated that altering the levels of one of the meiotic axis proteins changed which resolvase was used. Overall, the results presented by Medhi et al. show that differences in chromosome structure, in particular the relative concentration of meiotic axis proteins, influence how crossovers form in yeast. Future studies will investigate whether this is observed in other organisms such as humans, and whether local chromosome structure influences other steps of homologous recombination in meiosis. DOI:http://dx.doi.org/10.7554/eLife.19669.002
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Affiliation(s)
- Darpan Medhi
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States.,Sheffield Institute for Nucleic Acids, The University of Sheffield, Sheffield, United Kingdom.,Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
| | - Alastair Sh Goldman
- Sheffield Institute for Nucleic Acids, The University of Sheffield, Sheffield, United Kingdom.,Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
| | - Michael Lichten
- Laboratory of Biochemistry and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, United States
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9
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Gladyshev E, Kleckner N. Recombination-independent recognition of DNA homology for repeat-induced point mutation. Curr Genet 2016; 63:389-400. [PMID: 27628707 DOI: 10.1007/s00294-016-0649-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 09/04/2016] [Accepted: 09/06/2016] [Indexed: 12/31/2022]
Abstract
Numerous cytogenetic observations have shown that homologous chromosomes (or individual chromosomal loci) can engage in specific pairing interactions in the apparent absence of DNA breakage and recombination, suggesting that canonical recombination-mediated mechanisms may not be the only option for sensing DNA/DNA homology. One proposed mechanism for such recombination-independent homology recognition involves direct contacts between intact double-stranded DNA molecules. The strongest in vivo evidence for the existence of such a mechanism is provided by the phenomena of homology-directed DNA modifications in fungi, known as repeat-induced point mutation (RIP, discovered in Neurospora crassa) and methylation-induced premeiotically (MIP, discovered in Ascobolus immersus). In principle, Neurospora RIP can detect the presence of gene-sized DNA duplications irrespectively of their origin, underlying nucleotide sequence, coding capacity or relative, as well as absolute positions in the genome. Once detected, both sequence copies are altered by numerous cytosine-to-thymine (C-to-T) mutations that extend specifically over the duplicated region. We have recently shown that Neurospora RIP does not require MEI-3, the only RecA/Rad51 protein in this organism, consistent with a recombination-independent mechanism. Using an ultra-sensitive assay for RIP mutation, we have defined additional features of this process. We have shown that RIP can detect short islands of homology of only three base-pairs as long as many such islands are arrayed with a periodicity of 11 or 12 base-pairs along a pair of DNA molecules. While the presence of perfect homology is advantageous, it is not required: chromosomal segments with overall sequence identity of only 35-36 % can still be recognized by RIP. Importantly, in order for this process to work efficiently, participating DNA molecules must be able to co-align along their lengths. Based on these findings, we have proposed a model, in which sequence homology is detected by direct interactions between slightly-extended double-stranded DNAs. As a next step, it will be important to determine if the uncovered principles also apply to other processes that involve recombination-independent interactions between homologous chromosomal loci in vivo as well as to protein-free DNA/DNA interactions that were recently observed under biologically relevant conditions in vitro.
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Affiliation(s)
- Eugene Gladyshev
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, MA, 02138, USA.
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, MA, 02138, USA.
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Székvölgyi L, Ohta K, Nicolas A. Initiation of meiotic homologous recombination: flexibility, impact of histone modifications, and chromatin remodeling. Cold Spring Harb Perspect Biol 2015; 7:7/5/a016527. [PMID: 25934010 DOI: 10.1101/cshperspect.a016527] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Meiotic recombination is initiated by the formation of DNA double-strand breaks (DSBs) catalyzed by the evolutionary conserved Spo11 protein and accessory factors. DSBs are nonrandomly distributed along the chromosomes displaying a significant (~400-fold) variation of frequencies, which ultimately establishes local and long-range "hot" and "cold" domains for recombination initiation. This remarkable patterning is set up within the chromatin context, involving multiple layers of biochemical activity. Predisposed chromatin accessibility, but also a range of transcription factors, chromatin remodelers, and histone modifiers likely promote local recruitment of DSB proteins, as well as mobilization, sliding, and eviction of nucleosomes before and after the occurrence of meiotic DSBs. Here, we assess our understanding of meiotic DSB formation and methods to change its patterning. We also synthesize current heterogeneous knowledge on how histone modifications and chromatin remodeling may impact this decisive step in meiotic recombination.
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Affiliation(s)
- Lóránt Székvölgyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - Kunihiro Ohta
- Department of Life Sciences, The University of Tokyo, 113-8654 Tokyo, Japan
| | - Alain Nicolas
- Institut Curie Centre de Recherche, UMR3244 CNRS, Université Pierre et Marie Curie, 75248 Paris CEDEX 05, France
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11
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Kurdzo EL, Dawson DS. Centromere pairing--tethering partner chromosomes in meiosis I. FEBS J 2015; 282:2458-70. [PMID: 25817724 PMCID: PMC4490064 DOI: 10.1111/febs.13280] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/10/2015] [Accepted: 03/24/2015] [Indexed: 11/28/2022]
Abstract
In meiosis, homologous chromosomes face the obstacle of finding, holding onto and segregating away from their partner chromosome. There is increasing evidence, in a diverse range of organisms, that centromere–centromere interactions that occur in late prophase are an important mechanism in ensuring segregation fidelity. Centromere pairing appears to initiate when homologous chromosomes synapse in meiotic prophase. Structural proteins of the synaptonemal complex have been shown to help mediate centromere pairing, but how the structure that maintains centromere pairing differs from the structure of the synaptonemal complex along the chromosomal arms remains unknown. When the synaptonemal complex proteins disassemble from the chromosome arms in late prophase, some of these synaptonemal complex components persist at the centromeres. In yeast and Drosophila these centromere-pairing behaviors promote the proper segregation of chromosome partners that have failed to become linked by chiasmata. Recent studies of mouse spermatocytes have described centromere pairing behaviors that are similar in several respects to what has been described in the fly and yeast systems. In humans, chromosomes that fail to experience crossovers in meiosis are error-prone and are a major source of aneuploidy. The finding that centromere pairing is a conserved phenomenon raises the possibility that it may play a role in promoting the segregation fidelity of non-exchange chromosome pairs in humans.
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Affiliation(s)
- Emily L Kurdzo
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma, Health Science Center, OK, USA
| | - Dean S Dawson
- Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, and Department of Cell Biology, University of Oklahoma, Health Science Center, OK, USA
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12
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Anderson CA, Roberts S, Zhang H, Kelly CM, Kendall A, Lee C, Gerstenberger J, Koenig AB, Kabeche R, Gladfelter AS. Ploidy variation in multinucleate cells changes under stress. Mol Biol Cell 2015; 26:1129-40. [PMID: 25631818 PMCID: PMC4357512 DOI: 10.1091/mbc.e14-09-1375] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Aneuploidy and polyploidy can be beneficial or deleterious, depending on the context. In multinucleate fungal cells, mixed polyploidies can coexist in a common cytoplasm, but stress favors a return to haploid nuclei. Very low levels of aneuploidy are present, suggesting that there is limited buffering of ploidy variation despite a common cytosol. Ploidy variation is found in contexts as diverse as solid tumors, drug resistance in fungal infection, and normal development. Altering chromosome or genome copy number supports adaptation to fluctuating environments but is also associated with fitness defects attributed to protein imbalances. Both aneuploidy and polyploidy can arise from multinucleate states after failed cytokinesis or cell fusion. The consequences of ploidy variation in syncytia are difficult to predict because protein imbalances are theoretically buffered by a common cytoplasm. We examined ploidy in a naturally multinucleate fungus, Ashbya gossypii. Using integrated lac operator arrays, we found that chromosome number varies substantially among nuclei sharing a common cytoplasm. Populations of nuclei range from 1N to >4N, with different polyploidies in the same cell and low levels of aneuploidy. The degree of ploidy variation increases as cells age. In response to cellular stress, polyploid nuclei diminish and haploid nuclei predominate. These data suggest that mixed ploidy is tolerated in these syncytia; however, there may be costs associated with variation as stress homogenizes the genome content of nuclei. Furthermore, the results suggest that sharing of gene products is limited, and thus there is incomplete buffering of ploidy variation despite a common cytosol.
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Affiliation(s)
- Cori A Anderson
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Samantha Roberts
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Huaiying Zhang
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Courtney M Kelly
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Alexxy Kendall
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - ChangHwan Lee
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | | | - Aaron B Koenig
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Ruth Kabeche
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Amy S Gladfelter
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
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13
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Gladyshev E, Kleckner N. Direct recognition of homology between double helices of DNA in Neurospora crassa. Nat Commun 2014; 5:3509. [PMID: 24699390 PMCID: PMC4000310 DOI: 10.1038/ncomms4509] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 02/25/2014] [Indexed: 12/11/2022] Open
Abstract
Chromosomal regions of identical or nearly identical DNA sequence can preferentially associate with one another in the apparent absence of DNA breakage. Molecular mechanism(s) underlying such homology-dependent pairing phenomena remain(s) unknown. Using Neurospora crassa repeat-induced point mutation (RIP) as a model system, we show that a pair of DNA segments can be recognized as homologous if they share triplets of base pairs arrayed with the matching periodicity of 11 or 12 base pairs. This pattern suggests direct interactions between slightly underwound co-aligned DNA duplexes engaging once per turn and over many consecutive turns. The process occurs in the absence of MEI3, the only RAD51/DMC1 protein in N. crassa, demonstrating independence from the canonical homology recognition pathway. A new perspective is thus provided for further analysis of the breakage-independent recognition of homology that underlies RIP and, potentially, other processes where sequence-specific pairing of intact chromosomes is involved.
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Affiliation(s)
- Eugene Gladyshev
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, Massachusetts 02138, USA
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, 52 Oxford Street, Room NW140, Cambridge, Massachusetts 02138, USA
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Pradillo M, Varas J, Oliver C, Santos JL. On the role of AtDMC1, AtRAD51 and its paralogs during Arabidopsis meiosis. FRONTIERS IN PLANT SCIENCE 2014; 5:23. [PMID: 24596572 PMCID: PMC3925842 DOI: 10.3389/fpls.2014.00023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/20/2014] [Indexed: 05/02/2023]
Abstract
Meiotic recombination plays a critical role in achieving accurate chromosome segregation and increasing genetic diversity. Many studies, mostly in yeast, have provided important insights into the coordination and interplay between the proteins involved in the homologous recombination pathway, especially the recombinase RAD51 and the meiosis-specific DMC1. Here we summarize the current progresses on the function of both recombinases and the CX3 complex encoded by AtRAD51 paralogs, in the plant model species Arabidopsis thaliana. Similarities and differences respect to the function of these proteins in other organisms are also indicated.
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Affiliation(s)
- Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad Complutense de MadridMadrid, Spain
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15
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Residual recombination in Neurospora crassa spo11 deletion homozygotes occurs during meiosis. Mol Genet Genomics 2013; 288:437-44. [PMID: 23801409 DOI: 10.1007/s00438-013-0761-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/14/2013] [Indexed: 10/26/2022]
Abstract
Spo11 is considered responsible for initiation of meiotic recombination in higher organisms, but previous analysis using spo11 (RIP) mutants suggests that the his-3 region of Neurospora crassa experiences spo11-independent recombination. However, despite possessing several stop codons, it is conceivable that the mutants are not completely null. Also, since lack of spo11 interferes with chromosomal pairing and proper segregation at Meiosis I, spores can be partially diploid for a period after meiosis. Thus, it is possible that the recombination observed could be an abnormal event, occurring during the period of aneuploidy rather than during meiosis. To test the former hypothesis, we generated spo11 deletion homozygotes. Using crosses heteroallelic for his-3 mutations, we showed that His(+) progeny are generated in spo11 deletion homozygotes at a frequency at least as high as in wild type and, as in the spo11 (RIP) mutants, local crossing over is not reduced. To test the latter hypothesis, we utilised mutations in either end of a histone H1-GFP fusion gene, inserted between the recombination hotspot cog and his-3, in which GFP(+) spores arise as a result of recombination in a cross between the two GFP alleles. In a control cross homozygous for spo11 (+), the frequency at which GFP(+) spores arise is comparable to the frequency of His(+) spores and glowing nuclei first appear during prophase, prior to metaphase I, as expected for a product of meiotic recombination. Similarly in spo11 deletion homozygotes, GFP(+) spores arise at high frequency and glowing nuclei are first seen before metaphase, indicating that allelic recombination occurs during meiosis in the absence of spo11. We have therefore shown that spo11 is not essential for either his-3 allelic recombination or crossing over in the vicinity of his-3, and that spo11-independent allelic recombination is meiotic, indicating that there is a spo11-independent mechanism for initiation of recombination in Neurospora.
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Lui DY, Cahoon CK, Burgess SM. Multiple opposing constraints govern chromosome interactions during meiosis. PLoS Genet 2013; 9:e1003197. [PMID: 23341780 PMCID: PMC3547833 DOI: 10.1371/journal.pgen.1003197] [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: 11/11/2010] [Accepted: 11/12/2012] [Indexed: 11/24/2022] Open
Abstract
Homolog pairing and crossing over during meiosis I prophase is required for accurate chromosome segregation to form euploid gametes. The repair of Spo11-induced double-strand breaks (DSB) using a homologous chromosome template is a major driver of pairing in many species, including fungi, plants, and mammals. Inappropriate pairing and crossing over at ectopic loci can lead to chromosome rearrangements and aneuploidy. How (or if) inappropriate ectopic interactions are disrupted in favor of allelic interactions is not clear. Here we used an in vivo "collision" assay in budding yeast to test the contributions of cohesion and the organization and motion of chromosomes in the nucleus on promoting or antagonizing interactions between allelic and ectopic loci at interstitial chromosome sites. We found that deletion of the cohesin subunit Rec8, but not other chromosome axis proteins (e.g. Red1, Hop1, or Mek1), caused an increase in homolog-nonspecific chromosome interaction, even in the absence of Spo11. This effect was partially suppressed by expression of the mitotic cohesin paralog Scc1/Mdc1, implicating Rec8's role in cohesion rather than axis integrity in preventing nonspecific chromosome interactions. Disruption of telomere-led motion by treating cells with the actin polymerization inhibitor Latrunculin B (Lat B) elevated nonspecific collisions in rec8Δ spo11Δ. Next, using a visual homolog-pairing assay, we found that the delay in homolog pairing in mutants defective for telomere-led chromosome motion (ndj1Δ or csm4Δ) is enhanced in Lat B-treated cells, implicating actin in more than one process promoting homolog juxtaposition. We suggest that multiple, independent contributions of actin, cohesin, and telomere function are integrated to promote stable homolog-specific interactions and to destabilize weak nonspecific interactions by modulating the elastic spring-like properties of chromosomes.
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Affiliation(s)
- Doris Y. Lui
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Cori K. Cahoon
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Sean M. Burgess
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
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17
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Schoenmakers S, Wassenaar E, Hoogerbrugge JW, Laven JSE, Grootegoed JA, Baarends WM. Female meiotic sex chromosome inactivation in chicken. PLoS Genet 2009; 5:e1000466. [PMID: 19461881 PMCID: PMC2678266 DOI: 10.1371/journal.pgen.1000466] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 04/03/2009] [Indexed: 12/25/2022] Open
Abstract
During meiotic prophase in male mammals, the heterologous X and Y chromosomes remain largely unsynapsed, and meiotic sex chromosome inactivation (MSCI) leads to formation of the transcriptionally silenced XY body. In birds, the heterogametic sex is female, carrying Z and W chromosomes (ZW), whereas males have the homogametic ZZ constitution. During chicken oogenesis, the heterologous ZW pair reaches a state of complete heterologous synapsis, and this might enable maintenance of transcription of Z- and W chromosomal genes during meiotic prophase. Herein, we show that the ZW pair is transiently silenced, from early pachytene to early diplotene using immunocytochemistry and gene expression analyses. We propose that ZW inactivation is most likely achieved via spreading of heterochromatin from the W on the Z chromosome. Also, persistent meiotic DNA double-strand breaks (DSBs) may contribute to silencing of Z. Surprisingly, gammaH2AX, a marker of DSBs, and also the earliest histone modification that is associated with XY body formation in mammalian and marsupial spermatocytes, does not cover the ZW during the synapsed stage. However, when the ZW pair starts to desynapse, a second wave of gammaH2AX accumulates on the unsynapsed regions of Z, which also show a reappearance of the DSB repair protein RAD51. This indicates that repair of meiotic DSBs on the heterologous part of Z is postponed until late pachytene/diplotene, possibly to avoid recombination with regions on the heterologously synapsed W chromosome. Two days after entering diplotene, the Z looses gammaH2AX and shows reactivation. This is the first report of meiotic sex chromosome inactivation in a species with female heterogamety, providing evidence that this mechanism is not specific to spermatogenesis. It also indicates the presence of an evolutionary force that drives meiotic sex chromosome inactivation independent of the final achievement of synapsis.
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Affiliation(s)
- Sam Schoenmakers
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Evelyne Wassenaar
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Jos W. Hoogerbrugge
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Joop S. E. Laven
- Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - J. Anton Grootegoed
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
| | - Willy M. Baarends
- Department of Reproduction and Development, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
- * E-mail:
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Schoenmakers S, Wassenaar E, van Cappellen WA, Derijck AA, de Boer P, Laven JSE, Grootegoed JA, Baarends WM. Increased frequency of asynapsis and associated meiotic silencing of heterologous chromatin in the presence of irradiation-induced extra DNA double strand breaks. Dev Biol 2008; 317:270-81. [PMID: 18384767 DOI: 10.1016/j.ydbio.2008.02.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 02/11/2008] [Accepted: 02/13/2008] [Indexed: 11/18/2022]
Abstract
In meiotic prophase of male placental mammals, the heterologous X and Y chromosomes remain largely unsynapsed, which activates meiotic sex chromosome inactivation (MSCI), leading to formation of the transcriptionally silenced XY body. MSCI is most likely related to meiotic silencing of unsynapsed chromatin (MSUC), a mechanism that can silence autosomal unsynapsed chromatin. However, heterologous synapsis and escape from silencing also occur. In mammalian species, formation of DNA double strand breaks (DSBs) during leptotene precedes meiotic chromosome pairing. These DSBs are essential to achieve full synapsis of homologous chromosomes. We generated 25% extra meiotic DSBs by whole body irradiation of mice. This leads to a significant increase in meiotic recombination frequency. In mice carrying translocation chromosomes with synaptic problems, we observed an approximately 35% increase in asynapsis and MSUC of the nonhomologous region in the smallest chromosome pair following irradiation. However, the same nonhomologous region in the largest chromosome pair, shows complete synapsis and escape from MSUC in almost 100% of the nuclei, irrespective of exposure to irradiation. We propose that prevention of synapsis and associated activation of MSUC is linked to the presence of unrepaired meiotic DSBs in the nonhomologous region. Also, spreading of synaptonemal complex formation from regions of homology may act as an opposing force, and drive heterologous synapsis.
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Affiliation(s)
- Sam Schoenmakers
- Department of Reproduction and Development, Erasmus MC-University Medical Center, PO Box 2040, 3000 CA Rotterdam, The Netherlands
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Keeney S. Spo11 and the Formation of DNA Double-Strand Breaks in Meiosis. GENOME DYNAMICS AND STABILITY 2008; 2:81-123. [PMID: 21927624 PMCID: PMC3172816 DOI: 10.1007/7050_2007_026] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
Meiotic recombination is carried out through a specialized pathway for the formation and repair of DNA double-strand breaks made by the Spo11 protein, a relative of archaeal topoisomerase VI. This review summarizes recent studies that provide insight to the mechanism of DNA cleavage by Spo11, functional interactions of Spo11 with other proteins required for break formation, mechanisms that control the timing of recombination initiation, and evolutionary conservation and divergence of these processes.
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Affiliation(s)
- Scott Keeney
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021 USA,
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20
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Abstract
The sensing of accurate homologous recognition and pairing between discreet chromosomal regions and/or entire chromosomes entering meiosis is an essential step in ensuring correct alignment for recombination. A component of this is the recognition of heterology, which is required to prevent recombination at ectopic sites and between non-homologous chromosomes. It has been observed that a number of diverged organisms add an additional layer to this process: regions or chromosomes without a homologous counterpart are targeted for silencing during meiotic prophase I. This phenomenon was originally described in filamentous fungi, but has since been observed in nematodes and mammals. In this review we will generally group these phenomena under the title of meiotic silencing, and describe what is known about the process in the organisms in which it is observed. We will additionally propose that the functions of meiotic silencing originate in genome defense, and discuss its potential contributions to genome evolution and speciation.
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22
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Jin Y, Allan S, Baber L, Bhattarai EK, Lamb TM, Versaw WK. Rapid genetic mapping in Neurospora crassa. Fungal Genet Biol 2006; 44:455-65. [PMID: 17056287 PMCID: PMC1951786 DOI: 10.1016/j.fgb.2006.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 09/13/2006] [Accepted: 09/15/2006] [Indexed: 11/22/2022]
Abstract
Forward genetic analysis is the most broadly applicable approach to discern gene functions. However, for some organisms like the filamentous ascomycete Neurospora crassa, genetic mapping frequently represents a limiting step in forward genetic approaches. We describe an efficient method for genetic mapping in N. crassa that makes use of a modified bulked segregant analysis and PCR-based molecular markers. This method enables mapping with progeny from a single cross and requires only 90 PCR amplifications. Genetic distances between syntenic markers have been determined to ensure complete coverage of the genome and to allow interpolation of linkage data. As a result, most mutations should be mapped in less than one month to within 1-5 map units, a level of resolution sufficient to initiate map-based cloning efforts. This system also will facilitate analyses of recombination at a genome-wide level and is applicable to other perfect fungi when suitable markers are available.
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Affiliation(s)
| | | | | | | | | | - Wayne K. Versaw
- *Corresponding author: Wayne K. Versaw, , Telephone: 1-979-847-8587, Fax: 1-979-845-2891
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