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Yang Y, Wang N, Liu G, Nan W, Wang B, Gartner A, Zhang H, Hong Y. COSA-1 mediated pro-crossover complex formation promotes meiotic crossing over in C. elegans. Nucleic Acids Res 2024; 52:4375-4392. [PMID: 38412290 PMCID: PMC11077092 DOI: 10.1093/nar/gkae130] [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: 09/01/2023] [Revised: 02/03/2024] [Accepted: 02/11/2024] [Indexed: 02/29/2024] Open
Abstract
Accurate chromosome segregation during meiosis requires the establishment of at least one crossover (CO) between each pair of homologous chromosomes. CO formation depends on a group of conserved pro-CO proteins, which colocalize at CO-designated sites during late meiotic prophase I. However, it remains unclear whether these pro-CO proteins form a functional complex and how they promote meiotic CO formation in vivo. Here, we show that COSA-1, a key component required for CO formation, interacts with other pro-CO factors, MSH-5 and ZHP-3, via its N-terminal disordered region. Point mutations that impair these interactions do not affect CO designation, but they strongly hinder the accumulation of COSA-1 at CO-designated sites and result in defective CO formation. These defects can be partially bypassed by artificially tethering an interaction-compromised COSA-1 derivate to ZHP-3. Furthermore, we revealed that the accumulation of COSA-1 into distinct foci is required to assemble functional 'recombination nodules'. These prevent early CO-designated recombination intermediates from being dismantled by the RTEL-1 helicase and protect late recombination intermediates, such as Holliday junctions, until they are resolved by CO-specific resolvases. Altogether, our findings provide insight into COSA-1 mediated pro-CO complex assembly and its contribution to CO formation.
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Affiliation(s)
- Yuejun Yang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Nan Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Guoteng Liu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Wencong Nan
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Bin Wang
- National Key Laboratory of Non-food Biomass and Enzyme Technology, Guangxi Academy of Sciences, Nanning, China
| | - Anton Gartner
- Institute for Basic Sciences Center for Genomic Integrity, Graduate School for Health Sciences and Technology and Department for Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Hongtao Zhang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Ye Hong
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
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2
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Zou M, Shabala S, Zhao C, Zhou M. Molecular mechanisms and regulation of recombination frequency and distribution in plants. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2024; 137:86. [PMID: 38512498 PMCID: PMC10957645 DOI: 10.1007/s00122-024-04590-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 02/28/2024] [Indexed: 03/23/2024]
Abstract
KEY MESSAGE Recent developments in understanding the distribution and distinctive features of recombination hotspots are reviewed and approaches are proposed to increase recombination frequency in coldspot regions. Recombination events during meiosis provide the foundation and premise for creating new varieties of crops. The frequency of recombination in different genomic regions differs across eukaryote species, with recombination generally occurring more frequently at the ends of chromosomes. In most crop species, recombination is rare in centromeric regions. If a desired gene variant is linked in repulsion with an undesired variant of a second gene in a region with a low recombination rate, obtaining a recombinant plant combining two favorable alleles will be challenging. Traditional crop breeding involves combining desirable genes from parental plants into offspring. Therefore, understanding the mechanisms of recombination and factors affecting the occurrence of meiotic recombination is important for crop breeding. Here, we review chromosome recombination types, recombination mechanisms, genes and proteins involved in the meiotic recombination process, recombination hotspots and their regulation systems and discuss how to increase recombination frequency in recombination coldspot regions.
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Affiliation(s)
- Meilin Zou
- Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 1375, Prospect, TAS, 7250, Australia
| | - Sergey Shabala
- Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 1375, Prospect, TAS, 7250, Australia
- School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Perth, 6009, Australia
| | - Chenchen Zhao
- Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 1375, Prospect, TAS, 7250, Australia
| | - Meixue Zhou
- Tasmanian Institute of Agriculture, University of Tasmania, Private Bag 1375, Prospect, TAS, 7250, Australia.
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3
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Yun Y, Ito M, Sandhu S, Hunter N. Cytological Monitoring of Meiotic Crossovers in Spermatocytes and Oocytes. Methods Mol Biol 2021; 2153:267-286. [PMID: 32840786 DOI: 10.1007/978-1-0716-0644-5_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Crossing-over between homologous chromosomes is essential for accurate chromosome segregation at anaphase-I of meiosis. Defective crossing-over is associated with infertility, pregnancy miscarriage, and congenital disease. This chapter presents optimized protocols for the analysis of meiotic crossovers at the cytological level in spermatocytes and oocytes from mouse. The first approach employs immunocytology to detect MLH1, a DNA mismatch-repair protein that specifically marks crossover sites in the pachytene stage of meiotic prophase-I. These immunocytological methods have general utility for the analysis of other recombination steps, such as initiation and DNA strand exchange. The second approach visualizes chiasmata, the points of physical exchange between homologous chromosomes that are present during the diakinesis and metaphase-I stages. Both approaches are readily adaptable to the analysis of crossing over in other vertebrate species.
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Affiliation(s)
- Yan Yun
- Howard Hughes Medical Institute, Department of Microbiology and Molecular Genetics, Davis, University of California, Davis, CA, USA
| | - Masaru Ito
- Howard Hughes Medical Institute, Department of Microbiology and Molecular Genetics, Davis, University of California, Davis, CA, USA
| | - Sumit Sandhu
- Howard Hughes Medical Institute, Department of Microbiology and Molecular Genetics, Davis, University of California, Davis, CA, USA
| | - Neil Hunter
- Howard Hughes Medical Institute, Department of Microbiology and Molecular Genetics, Davis, University of California, Davis, CA, USA.
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4
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Cahoon CK, Helm JM, Libuda DE. Synaptonemal Complex Central Region Proteins Promote Localization of Pro-crossover Factors to Recombination Events During Caenorhabditis elegans Meiosis. Genetics 2019; 213:395-409. [PMID: 31431470 PMCID: PMC6781886 DOI: 10.1534/genetics.119.302625] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 08/16/2019] [Indexed: 11/23/2022] Open
Abstract
Crossovers (COs) between homologous chromosomes are critical for meiotic chromosome segregation and form in the context of the synaptonemal complex (SC), a meiosis-specific structure that assembles between aligned homologs. During Caenorhabditis elegans meiosis, central region components of the SC (SYP proteins) are essential to repair double-strand DNA breaks (DSBs) as COs. Here, we investigate the relationships between the SYP proteins and conserved pro-CO factors by examining the immunolocalization of these proteins in meiotic mutants where SYP proteins are absent, reduced, or mislocalized. Although COs do not form in syp null mutants, pro-CO factors COSA-1, MSH-5, and ZHP-3 nevertheless colocalize at DSB-dependent sites during late prophase, reflecting an inherent affinity of these factors for DSB repair sites. In contrast, in mutants where SYP proteins are present but form aggregates or display abnormal synapsis, pro-CO factors consistently track with SYP-1 localization. Further, pro-CO factors usually localize to a single site per SYP-1 structure, even in SYP aggregates or in mutants where the SC forms between sister chromatids, suggesting that CO regulation occurs within these aberrant SC structures. Moreover, we find that the meiotic cohesin REC-8 is required to ensure that SC formation occurs between homologs and not sister chromatids. Taken together, our findings support a model in which SYP proteins promote CO formation by promoting the localization of pro-CO factors to recombination events within an SC compartment, thereby ensuring that pro-CO factors identify a recombination event within an SC structure and that CO maturation occurs only between properly aligned homologous chromosomes.
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Affiliation(s)
- Cori K Cahoon
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
| | - Jacquellyn M Helm
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
| | - Diana E Libuda
- Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
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5
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Hartmann M, Umbanhowar J, Sekelsky J. Centromere-Proximal Meiotic Crossovers in Drosophila melanogaster Are Suppressed by Both Highly Repetitive Heterochromatin and Proximity to the Centromere. Genetics 2019; 213:113-125. [PMID: 31345993 PMCID: PMC6727794 DOI: 10.1534/genetics.119.302509] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/19/2019] [Indexed: 11/18/2022] Open
Abstract
Crossovers are essential in meiosis of most organisms to ensure the proper segregation of chromosomes, but improper placement of crossovers can result in nondisjunction and aneuploidy in progeny. In particular, crossovers near the centromere can cause nondisjunction. Centromere-proximal crossovers are suppressed by what is termed the centromere effect, but the mechanism is unknown. Here, we investigate contributions to centromere-proximal crossover suppression in Drosophila melanogaster We mapped a large number of centromere-proximal crossovers, and find that crossovers are essentially absent from the highly repetitive (HR)-heterochromatin surrounding the centromere but occur at a low frequency within the less-repetitive (LR)-heterochromatic region and adjacent euchromatin. Previous research suggested that flies that lack the Bloom syndrome helicase (Blm) lose meiotic crossover patterning, including the centromere effect. Mapping of centromere-proximal crossovers in Blm mutants reveals that the suppression within the HR-heterochromatin is intact, but the distance-dependent centromere effect is lost. We conclude that centromere-proximal crossovers are suppressed by two separable mechanisms: an HR-heterochromatin effect that completely suppresses crossovers in the HR-heterochromatin, and the centromere effect, which suppresses crossovers with a dissipating effect with distance from the centromere.
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Affiliation(s)
- Michaelyn Hartmann
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - James Umbanhowar
- Environment, Ecology and Energy Program, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Jeff Sekelsky
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599
- Integrative Program in Biological and Genome Sciences, University of North Carolina, Chapel Hill, North Carolina 27599
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6
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The PSMA8 subunit of the spermatoproteasome is essential for proper meiotic exit and mouse fertility. PLoS Genet 2019; 15:e1008316. [PMID: 31437213 PMCID: PMC6726247 DOI: 10.1371/journal.pgen.1008316] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 09/04/2019] [Accepted: 07/17/2019] [Indexed: 01/01/2023] Open
Abstract
The ubiquitin proteasome system regulates meiotic recombination in yeast through its association with the synaptonemal complex, a ‘zipper’-like structure that holds homologous chromosome pairs in synapsis during meiotic prophase I. In mammals, the proteasome activator subunit PA200 targets acetylated histones for degradation during somatic DNA double strand break repair and during histone replacement during spermiogenesis. We investigated the role of the testis-specific proteasomal subunit α4s (PSMA8) during spermatogenesis, and found that PSMA8 was localized to and dependent on the central region of the synaptonemal complex. Accordingly, synapsis-deficient mice show delocalization of PSMA8. Moreover, though Psma8-deficient mice are proficient in meiotic homologous recombination, there are alterations in the proteostasis of several key meiotic players that, in addition to the known substrate acetylated histones, have been shown by a proteomic approach to interact with PSMA8, such as SYCP3, SYCP1, CDK1 and TRIP13. These alterations lead to an accumulation of spermatocytes in metaphase I and II which either enter massively into apoptosis or give rise to a low number of aberrant round spermatids that apoptose before histone replacement takes place. Proteins within the cells that are unnecessary or damaged are degraded by a large protein complex named the proteasome. The proteins to be degraded are marked by a small protein called ubiquitin. The addition of a small modification (acetyl group) to some proteins also promotes their degradation by the proteasome. Proteasomal degradation of proteins is an essential mechanism for many developmental programs including gametogenesis, a process whereby a diploid cell produces a haploid cell or gamete (sperm or egg). The mechanism by which this genome reduction occurs is called meiosis. Here, we report the study of a protein, named PSMA8 that is specific for the testis proteasome in vertebrates. Using the mouse as a model, we show that loss of PSMA8 leads to infertility in males. By co-immunoprecipitation-coupled mass spectroscopy we identified a large list of novel PSMA8 interacting proteins. We focused our functional analysis on several key meiotic proteins which were accumulated such as SYCP3, SYCP1, CDK1 and TRIP13 in addition to the known substrate of the spermatoproteasome, the acetylated histones. We suggest that the altered accumulation of these important proteins causes a disequilibrium of the meiotic division that produces apoptotic spermatocytes in metaphase I and II and also early spermatids that die soon after reaching this stage.
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Lake CM, Nielsen RJ, Bonner AM, Eche S, White-Brown S, McKim KS, Hawley RS. Narya, a RING finger domain-containing protein, is required for meiotic DNA double-strand break formation and crossover maturation in Drosophila melanogaster. PLoS Genet 2019; 15:e1007886. [PMID: 30615609 PMCID: PMC6336347 DOI: 10.1371/journal.pgen.1007886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/17/2019] [Accepted: 12/10/2018] [Indexed: 11/19/2022] Open
Abstract
Meiotic recombination, which is necessary to ensure that homologous chromosomes segregate properly, begins with the induction of meiotic DNA double-strand breaks (DSBs) and ends with the repair of a subset of those breaks into crossovers. Here we investigate the roles of two paralogous genes, CG12200 and CG31053, which we have named Narya and Nenya, respectively, due to their relationship with a structurally similar protein named Vilya. We find that narya recently evolved from nenya by a gene duplication event, and we show that these two RING finger domain-containing proteins are functionally redundant with respect to a critical role in DSB formation. Narya colocalizes with Vilya foci, which are known to define recombination nodules, or sites of crossover formation. A separation-of-function allele of narya retains the capacity for DSB formation but cannot mature those DSBs into crossovers. We further provide data on the physical interaction of Narya, Nenya and Vilya, as assayed by the yeast two-hybrid system. Together these data support the view that all three RING finger domain-containing proteins function in the formation of meiotic DNA DSBs and in the process of crossing over. Errors in chromosome segregation during meiosis are the leading cause of miscarriages and can result in genetic abnormalities like Down syndrome or Turner syndrome. For chromosomes to segregate faithfully, they must recombine with their homolog during the early steps of meiosis. An essential component of the process of meiotic recombination is creating the lesions (double-strand breaks, DSBs) that are required to form a crossover with the homologous chromosome. Crossovers are required to ensure chromosomes segregate properly at the first meiotic division. In this study we have identified two genes, narya and nenya, that are essential in DSB formation. We found that narya arose from a duplication of nenya, and these two genes are functionally redundant. In addition to its role in DSB formation, narya also plays a role in processing DSBs into crossovers. Strengthening our knowledge about the mechanism by which Narya both creates DSBs and processes them into crossovers will lead to a better understanding of the process of meiotic chromosome segregation not only in flies but many other organisms, as these genes have homologs in yeast, worms, plants, mice and humans.
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Affiliation(s)
- Cathleen M. Lake
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Rachel J. Nielsen
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Amanda M. Bonner
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Salam Eche
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Sanese White-Brown
- Waksman Institute and Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Kim S. McKim
- Waksman Institute and Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America
| | - R. Scott Hawley
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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8
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Okagaki RJ, Dukowic-Schulze S, Eggleston WB, Muehlbauer GJ. A Critical Assessment of 60 Years of Maize Intragenic Recombination. FRONTIERS IN PLANT SCIENCE 2018; 9:1560. [PMID: 30420864 PMCID: PMC6215864 DOI: 10.3389/fpls.2018.01560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/04/2018] [Indexed: 06/09/2023]
Abstract
Until the mid-1950s, it was believed that genetic crossovers did not occur within genes. Crossovers occurred between genes, the "beads on a string" model. Then in 1956, Seymour Benzer published his classic paper describing crossing over within a gene, intragenic recombination. This result from a bacteriophage gene prompted Oliver Nelson to study intragenic recombination in the maize Waxy locus. His studies along with subsequent work by others working with maize and other organisms described the outcomes of intragenic recombination and provided some of the earliest evidence that genes, not intergenic regions, were recombination hotspots. High-throughput genotyping approaches have since replaced single gene intragenic studies for characterizing the outcomes of recombination. These large-scale studies confirm that genes, or more generally genic regions, are the most active recombinogenic regions, and suggested a pattern of crossovers similar to the budding yeast Saccharomyces cerevisiae. In S. cerevisiae recombination is initiated by double-strand breaks (DSBs) near transcription start sites (TSSs) of genes producing a polarity gradient where crossovers preferentially resolve at the 5' end of genes. Intragenic studies in maize yielded less evidence for either polarity or for DSBs near TSSs initiating recombination and in certain respects resembled Schizosaccharomyces pombe or mouse. These different perspectives highlight the need to draw upon the strengths of different approaches and caution against relying on a single model system or approach for understanding recombination.
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Affiliation(s)
- Ron J. Okagaki
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, United States
| | | | - William B. Eggleston
- Department of Biology, Virginia Commonwealth University, St. Paul, MN, United States
| | - Gary J. Muehlbauer
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN, United States
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, United States
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9
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Female Meiosis: Synapsis, Recombination, and Segregation in Drosophila melanogaster. Genetics 2018; 208:875-908. [PMID: 29487146 PMCID: PMC5844340 DOI: 10.1534/genetics.117.300081] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/18/2017] [Indexed: 12/11/2022] Open
Abstract
A century of genetic studies of the meiotic process in Drosophila melanogaster females has been greatly augmented by both modern molecular biology and major advances in cytology. These approaches, and the findings they have allowed, are the subject of this review. Specifically, these efforts have revealed that meiotic pairing in Drosophila females is not an extension of somatic pairing, but rather occurs by a poorly understood process during premeiotic mitoses. This process of meiotic pairing requires the function of several components of the synaptonemal complex (SC). When fully assembled, the SC also plays a critical role in maintaining homolog synapsis and in facilitating the maturation of double-strand breaks (DSBs) into mature crossover (CO) events. Considerable progress has been made in elucidating not only the structure, function, and assembly of the SC, but also the proteins that facilitate the formation and repair of DSBs into both COs and noncrossovers (NCOs). The events that control the decision to mature a DSB as either a CO or an NCO, as well as determining which of the two CO pathways (class I or class II) might be employed, are also being characterized by genetic and genomic approaches. These advances allow a reconsideration of meiotic phenomena such as interference and the centromere effect, which were previously described only by genetic studies. In delineating the mechanisms by which the oocyte controls the number and position of COs, it becomes possible to understand the role of CO position in ensuring the proper orientation of homologs on the first meiotic spindle. Studies of bivalent orientation have occurred in the context of numerous investigations into the assembly, structure, and function of the first meiotic spindle. Additionally, studies have examined the mechanisms ensuring the segregation of chromosomes that have failed to undergo crossing over.
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10
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Tiemann-Boege I, Schwarz T, Striedner Y, Heissl A. The consequences of sequence erosion in the evolution of recombination hotspots. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0462. [PMID: 29109225 PMCID: PMC5698624 DOI: 10.1098/rstb.2016.0462] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2017] [Indexed: 12/18/2022] Open
Abstract
Meiosis is initiated by a double-strand break (DSB) introduced in the DNA by a highly controlled process that is repaired by recombination. In many organisms, recombination occurs at specific and narrow regions of the genome, known as recombination hotspots, which overlap with regions enriched for DSBs. In recent years, it has been demonstrated that conversions and mutations resulting from the repair of DSBs lead to a rapid sequence evolution at recombination hotspots eroding target sites for DSBs. We still do not fully understand the effect of this erosion in the recombination activity, but evidence has shown that the binding of trans-acting factors like PRDM9 is affected. PRDM9 is a meiosis-specific, multi-domain protein that recognizes DNA target motifs by its zinc finger domain and directs DSBs to these target sites. Here we discuss the changes in affinity of PRDM9 to eroded recognition sequences, and explain how these changes in affinity of PRDM9 can affect recombination, leading sometimes to sterility in the context of hybrid crosses. We also present experimental data showing that DNA methylation reduces PRDM9 binding in vitro. Finally, we discuss PRDM9-independent hotspots, posing the question how these hotspots evolve and change with sequence erosion. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
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Affiliation(s)
- Irene Tiemann-Boege
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Theresa Schwarz
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Yasmin Striedner
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Angelika Heissl
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
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Abstract
Meiosis halves diploid chromosome numbers to haploid levels that are essential for sexual reproduction in most eukaryotes. Meiotic recombination ensures the formation of bivalents between homologous chromosomes (homologs) and their subsequent proper segregation. It also results in genetic diversity among progeny that influences evolutionary responses to selection. Moreover, crop breeding depends upon the action of meiotic recombination to rearrange elite traits between parental chromosomes. An understanding of the molecular mechanisms that drive meiotic recombination is important for both fundamental research and practical applications. This review emphasizes advances made during the past 5 years, primarily in Arabidopsis and rice, by summarizing newly characterized genes and proteins and examining the regulatory mechanisms that modulate their action.
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Affiliation(s)
- Yingxiang Wang
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China;
| | - Gregory P Copenhaver
- Department of Biology and the Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3280, USA;
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-3280, USA
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12
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Affiliation(s)
- Monique Zetka
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
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13
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Ahuja JS, Sandhu R, Mainpal R, Lawson C, Henley H, Hunt PA, Yanowitz JL, Börner GV. Control of meiotic pairing and recombination by chromosomally tethered 26S proteasome. Science 2017; 355:408-411. [PMID: 28059715 DOI: 10.1126/science.aaf4778] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 09/12/2016] [Accepted: 12/05/2016] [Indexed: 12/11/2022]
Abstract
During meiosis, paired homologous chromosomes (homologs) become linked via the synaptonemal complex (SC) and crossovers. Crossovers mediate homolog segregation and arise from self-inflicted double-strand breaks (DSBs). Here, we identified a role for the proteasome, the multisubunit protease that degrades proteins in the nucleus and cytoplasm, in homolog juxtaposition and crossing over. Without proteasome function, homologs failed to pair and instead remained associated with nonhomologous chromosomes. Although dispensable for noncrossover formation, a functional proteasome was required for a coordinated transition that entails SC assembly between longitudinally organized chromosome axes and stable strand exchange of crossover-designated DSBs. Notably, proteolytic core and regulatory proteasome particles were recruited to chromosomes by Zip3, the ortholog of mammalian E3 ligase RNF212, and SC protein Zip1 . We conclude that proteasome functions along meiotic chromosomes are evolutionarily conserved.
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Affiliation(s)
- Jasvinder S Ahuja
- Center for Gene Regulation in Health and Disease and Department of Biological, Geological and Environmental Sciences, Cleveland State University (CSU), Cleveland, OH, USA
| | - Rima Sandhu
- Center for Gene Regulation in Health and Disease and Department of Biological, Geological and Environmental Sciences, Cleveland State University (CSU), Cleveland, OH, USA
| | - Rana Mainpal
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Crystal Lawson
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, WA, USA
| | - Hanna Henley
- Center for Gene Regulation in Health and Disease and Department of Biological, Geological and Environmental Sciences, Cleveland State University (CSU), Cleveland, OH, USA
| | - Patricia A Hunt
- School of Molecular Biosciences, Center for Reproductive Biology, Washington State University, Pullman, WA, USA
| | - Judith L Yanowitz
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - G Valentin Börner
- Center for Gene Regulation in Health and Disease and Department of Biological, Geological and Environmental Sciences, Cleveland State University (CSU), Cleveland, OH, USA. .,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, USA.,Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Calvente A, Santos JL, Rufas JS. Do Exogenous DNA Double-Strand Breaks Change Incomplete Synapsis and Chiasma Localization in the Grasshopper Stethophyma grossum? PLoS One 2016; 11:e0168499. [PMID: 28005992 PMCID: PMC5179137 DOI: 10.1371/journal.pone.0168499] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/30/2016] [Indexed: 01/15/2023] Open
Abstract
Meiotic recombination occurs as a programmed event that initiates by the formation of DNA double-strand breaks (DSBs) that give rise to the formation of crossovers that are observed as chiasmata. Chiasmata are essential for the accurate chromosome segregation and the generation of new combinations of parental alleles. Some treatments that provoke exogenous DSBs also lead to alterations in the recombination pattern of some species in which full homologous synapsis is achieved at pachytene. We have carried out a similar approach in males of the grasshopper Stethophyma grossum, whose homologues show incomplete synapsis and proximal chiasma localization. After irradiating males with γ rays we have studied the distribution of both the histone variant γ-H2AX and the recombinase RAD51. These proteins are cytological markers of DSBs at early prophase I. We have inferred synaptonemal complex (SC) formation via identification of SMC3 and RAD 21 cohesin subunits. Whereas thick and thin SMC3 filaments would correspond to synapsed and unsynapsed regions, the presence of RAD21 is only restricted to synapsed regions. Results show that irradiated spermatocytes maintain restricted synapsis between homologues. However, the frequency and distribution of chiasmata in metaphase I bivalents is slightly changed and quadrivalents were also observed. These results could be related to the singular nuclear polarization displayed by the spermatocytes of this species.
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Affiliation(s)
- Adela Calvente
- Departamento de Biología, Edificio de Biológicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Luis Santos
- Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - Julio S. Rufas
- Departamento de Biología, Edificio de Biológicas, Universidad Autónoma de Madrid, Madrid, Spain
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Hatkevich T, Kohl KP, McMahan S, Hartmann MA, Williams AM, Sekelsky J. Bloom Syndrome Helicase Promotes Meiotic Crossover Patterning and Homolog Disjunction. Curr Biol 2016; 27:96-102. [PMID: 27989672 DOI: 10.1016/j.cub.2016.10.055] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 11/28/2022]
Abstract
In most sexually reproducing organisms, crossover formation between homologous chromosomes is necessary for proper chromosome disjunction during meiosis I. During meiotic recombination, a subset of programmed DNA double-strand breaks (DSBs) are repaired as crossovers, with the remainder becoming noncrossovers [1]. Whether a repair intermediate is designated to become a crossover is a highly regulated decision that integrates several crossover patterning processes, both along chromosome arms (interference and the centromere effect) and between chromosomes (crossover assurance) [2]. Because the mechanisms that generate crossover patterning have remained elusive for over a century, it has been difficult to assess the relationship between crossover patterning and meiotic chromosome behavior. We show here that meiotic crossover patterning is lost in Drosophila melanogaster mutants that lack the Bloom syndrome helicase. In the absence of interference and the centromere effect, crossovers are distributed more uniformly along chromosomes. Crossovers even occur on the small chromosome 4, which normally never has meiotic crossovers [3]. Regulated distribution of crossovers between chromosome pairs is also lost, resulting in an elevated frequency of homologs that do not receive a crossover, which in turn leads to elevated nondisjunction.
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Affiliation(s)
- Talia Hatkevich
- Curriculum in Genetics and Molecular Biology, 120 Mason Farm Road, University of North Carolina, Chapel Hill, NC 27599-7264, USA
| | - Kathryn P Kohl
- Department of Biology, Winthrop University, 701 Oakland Avenue, Rock Hill, SC 29733, USA
| | - Susan McMahan
- Department of Biology, University of North Carolina, 120 South Road, Chapel Hill, NC 27599-3280, USA; Integrative Program in Biological and Genome Sciences, 250 Bell Tower Drive, University of North Carolina, Chapel Hill, NC 27599-7100, USA
| | - Michaelyn A Hartmann
- Curriculum in Genetics and Molecular Biology, 120 Mason Farm Road, University of North Carolina, Chapel Hill, NC 27599-7264, USA
| | - Andrew M Williams
- Department of Biology, Winthrop University, 701 Oakland Avenue, Rock Hill, SC 29733, USA
| | - Jeff Sekelsky
- Curriculum in Genetics and Molecular Biology, 120 Mason Farm Road, University of North Carolina, Chapel Hill, NC 27599-7264, USA; Department of Biology, University of North Carolina, 120 South Road, Chapel Hill, NC 27599-3280, USA; Integrative Program in Biological and Genome Sciences, 250 Bell Tower Drive, University of North Carolina, Chapel Hill, NC 27599-7100, USA.
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To Break or Not To Break: Sex Chromosome Hemizygosity During Meiosis in Caenorhabditis. Genetics 2016; 204:999-1013. [PMID: 27605052 DOI: 10.1534/genetics.116.194308] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 09/06/2016] [Indexed: 11/18/2022] Open
Abstract
Meiotic recombination establishes connections between homologous chromosomes to promote segregation. Hemizygous regions of sex chromosomes have no homologous chromosome to recombine with, yet must be transmitted through meiosis. An extreme case of hemizygosity exists in the genus Caenorhabditis, where males have a single X chromosome that completely lacks a homologous partner. To determine whether similar strategies have evolved to accommodate hemizygosity of the X during male meiosis in Caenorhabditis with distinct modes of sexual reproduction, we examined induction and processing of meiotic double strand breaks (DSBs) in androdioecious (hermaphrodite/male) Caenorhabditis elegans and C. briggsae, and gonochoristic (female/male) C. remanei and C. brenneri Analysis of the recombinase RAD-51 suggests more meiotic DSBs are induced in gonochoristic vs. androdioecious species. However, in late prophase in all species, chromosome pairs are restructured into bivalents around a single axis, suggesting that the holocentric nature of Caenorhabditis chromosomes dictates a single crossover per bivalent regardless of the number of DSBs induced. Interestingly, RAD-51 foci were readily observed on the X chromosome of androdioecious male germ cells, while very few were detected in gonochoristic male germ cells. As in C. elegans, the X chromosome in C. briggsae male germ cells undergoes transient pseudosynapsis and flexibility in DSB repair pathway choice. In contrast, in C. remanei and C. brenneri male germ cells, the X chromosome does not undergo pseudosynapsis and appears refractory to SPO-11-induced breaks. Together our results suggest that distinct strategies have evolved to accommodate sex chromosome hemizygosity during meiosis in closely related Caenorhabditis species.
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