151
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Morgan CH, Zhang H, Bomblies K. Are the effects of elevated temperature on meiotic recombination and thermotolerance linked via the axis and synaptonemal complex? Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0470. [PMID: 29109229 PMCID: PMC5698628 DOI: 10.1098/rstb.2016.0470] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2017] [Indexed: 12/23/2022] Open
Abstract
Meiosis is unusual among cell divisions in shuffling genetic material by crossovers among homologous chromosomes and partitioning the genome into haploid gametes. Crossovers are critical for chromosome segregation in most eukaryotes, but are also an important factor in evolution, as they generate novel genetic combinations. The molecular mechanisms that underpin meiotic recombination and chromosome segregation are well conserved across kingdoms, but are also sensitive to perturbation by environment, especially temperature. Even subtle shifts in temperature can alter the number and placement of crossovers, while at greater extremes, structural failures can occur in the linear axis and synaptonemal complex structures which are essential for recombination and chromosome segregation. Understanding the effects of temperature on these processes is important for its implications in evolution and breeding, especially in the context of global warming. In this review, we first summarize the process of meiotic recombination and its reliance on axis and synaptonemal complex structures, and then discuss effects of temperature on these processes and structures. We hypothesize that some consistent effects of temperature on recombination and meiotic thermotolerance may commonly be two sides of the same coin, driven by effects of temperature on the folding or interaction of key meiotic proteins. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
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Affiliation(s)
| | - Huakun Zhang
- John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
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152
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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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153
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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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154
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Wendorff TJ, Berger JM. Topoisomerase VI senses and exploits both DNA crossings and bends to facilitate strand passage. eLife 2018; 7:31724. [PMID: 29595473 PMCID: PMC5922973 DOI: 10.7554/elife.31724] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 03/28/2018] [Indexed: 01/09/2023] Open
Abstract
Type II topoisomerases manage DNA supercoiling and aid chromosome segregation using a complex, ATP-dependent duplex strand passage mechanism. Type IIB topoisomerases and their homologs support both archaeal/plant viability and meiotic recombination. Topo VI, a prototypical type IIB topoisomerase, comprises two Top6A and two Top6B protomers; how these subunits cooperate to engage two DNA segments and link ATP turnover to DNA transport is poorly understood. Using multiple biochemical approaches, we show that Top6B, which harbors the ATPase activity of topo VI, recognizes and exploits the DNA crossings present in supercoiled DNA to stimulate subunit dimerization by ATP. Top6B self-association in turn induces extensive DNA bending, which is needed to support duplex cleavage by Top6A. Our observations explain how topo VI tightly coordinates DNA crossover recognition and ATP binding with strand scission, providing useful insights into the operation of type IIB topoisomerases and related meiotic recombination and GHKL ATPase machineries. Each human cell contains genetic information stored on approximately two meters of DNA. Like holiday lights in a storage box, packing so much DNA into such a small space leads to its entanglement. This snarled DNA prevents the cell from properly accessing and copying its genes. Type II topoisomerases are a group of enzymes that remove DNA tangles. They attach to one segment of a DNA tangle, cut it in half, remove the knot, and then repair the broken DNA strand. The process requires the proteins to ‘burn’ chemical energy. If topoisomerases make mistakes when they cut and reseal DNA, they could damage genetic information and harm cells. It is still unclear how these proteins recognize DNA tangles and use energy to remove knots instead of adding them. Here, Wendorff and Berger use biochemical approaches to look into topo VI, a type II topoisomerase found in plants and certain single-celled organisms. When DNA is tangled, it forms sharp bends and crossings. Their experiments reveal that topo VI has certain ‘sensors’ that detect where DNA bends, and others that recognize the crossings. Only when both features are present does the enzyme start working and using energy. These sensors act as fail-safes to ensure that topo VI only breaks DNA when it encounters a proper knot, and is not ‘set loose’ on untangled DNA. Future work will look at topo VI at an atom-by-atom level to reveal how exactly the enzymes ‘see’ DNA bends and crossings, and how interactions with the correct type of DNA triggers energy use and DNA untangling. Knowing more about topo VI can help researchers to understand how human and bacterial topoisomerases work. These results could also be generalized to other enzymes, for example those that help the genetic processes at play when sperm and egg cells form.
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Affiliation(s)
- Timothy J Wendorff
- Biophysics Graduate Program, University of California, Berkeley, Berkeley, United States
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, United States
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155
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Nath A, Karthikeyan S. Enhanced prediction of recombination hotspots using input features extracted by class specific autoencoders. J Theor Biol 2018; 444:73-82. [PMID: 29462625 DOI: 10.1016/j.jtbi.2018.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 01/12/2018] [Accepted: 02/16/2018] [Indexed: 10/18/2022]
Abstract
In yeast and in some mammals the frequencies of recombination are high in some genomic locations which are known as recombination hotspots and in the locations where the recombination is below average are consequently known as coldspots. Knowledge of the hotspot regions gives clues about understanding the meiotic process and also in understanding the possible effects of sequence variation in these regions. Moreover, accurate information about the hotspot and coldspot regions can reveal insights into the genome evolution. In the present work, we have used class specific autoencoders for feature extraction and reduction. Subsequently the deep features that are extracted from the autoencoders were used to train three different classifiers, namely: gradient boosting machines, random forest and deep learning neural networks for predicting the hotspot and coldspot regions. A comparative performance analysis was carried out by experimenting on deep features extracted from different sets of the training data using autoencoders for selecting the best set of deep features. It was observed that learning algorithms trained on features extracted from the combined class specific autoencoder out performed when compared with the performances of these learning algorithms trained with other sets of deep features. So the combined class-specific autoencoder based feature extraction can be applied to a growing range of biological problems to achieve superior prediction performance.
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Affiliation(s)
- Abhigyan Nath
- Department of Computer Science, Banaras Hindu University, Varanasi 221005, India.
| | - S Karthikeyan
- Department of Computer Science, Banaras Hindu University, Varanasi 221005, India
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156
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Delgado JL, Hsieh CM, Chan NL, Hiasa H. Topoisomerases as anticancer targets. Biochem J 2018; 475:373-398. [PMID: 29363591 PMCID: PMC6110615 DOI: 10.1042/bcj20160583] [Citation(s) in RCA: 260] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/14/2017] [Accepted: 12/21/2017] [Indexed: 12/15/2022]
Abstract
Many cancer type-specific anticancer agents have been developed and significant advances have been made toward precision medicine in cancer treatment. However, traditional or nonspecific anticancer drugs are still important for the treatment of many cancer patients whose cancers either do not respond to or have developed resistance to cancer-specific anticancer agents. DNA topoisomerases, especially type IIA topoisomerases, are proved therapeutic targets of anticancer and antibacterial drugs. Clinically successful topoisomerase-targeting anticancer drugs act through topoisomerase poisoning, which leads to replication fork arrest and double-strand break formation. Unfortunately, this unique mode of action is associated with the development of secondary cancers and cardiotoxicity. Structures of topoisomerase-drug-DNA ternary complexes have revealed the exact binding sites and mechanisms of topoisomerase poisons. Recent advances in the field have suggested a possibility of designing isoform-specific human topoisomerase II poisons, which may be developed as safer anticancer drugs. It may also be possible to design catalytic inhibitors of topoisomerases by targeting certain inactive conformations of these enzymes. Furthermore, identification of various new bacterial topoisomerase inhibitors and regulatory proteins may inspire the discovery of novel human topoisomerase inhibitors. Thus, topoisomerases remain as important therapeutic targets of anticancer agents.
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Affiliation(s)
- Justine L Delgado
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, U.S.A
| | - Chao-Ming Hsieh
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei City 100, Taiwan
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei City 100, Taiwan
| | - Hiroshi Hiasa
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, U.S.A.
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157
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Osman K, Yang J, Roitinger E, Lambing C, Heckmann S, Howell E, Cuacos M, Imre R, Dürnberger G, Mechtler K, Armstrong S, Franklin FCH. Affinity proteomics reveals extensive phosphorylation of the Brassica chromosome axis protein ASY1 and a network of associated proteins at prophase I of meiosis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:17-33. [PMID: 29078019 PMCID: PMC5767750 DOI: 10.1111/tpj.13752] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 10/10/2017] [Accepted: 10/17/2017] [Indexed: 05/18/2023]
Abstract
During meiosis, the formation of crossovers (COs) generates genetic variation and provides physical links that are essential for accurate chromosome segregation. COs occur in the context of a proteinaceous chromosome axis. The transcriptomes and proteomes of anthers and meiocytes comprise several thousand genes and proteins, but because of the level of complexity relatively few have been functionally characterized. Our understanding of the physical and functional interactions between meiotic proteins is also limited. Here we use affinity proteomics to analyse the proteins that are associated with the meiotic chromosome axis protein, ASY1, in Brassica oleracea anthers and meiocytes. We show that during prophase I ASY1 and its interacting partner, ASY3, are extensively phosphorylated, and we precisely assign phosphorylation sites. We identify 589 proteins that co-immunoprecipitate with ASY1. These correspond to 492 Arabidopsis orthologues, over 90% of which form a coherent protein-protein interaction (PPI) network containing known and candidate meiotic proteins, including proteins more usually associated with other cellular processes such as DNA replication and proteolysis. Mutant analysis confirms that affinity proteomics is a viable strategy for revealing previously unknown meiotic proteins, and we show how the PPI network can be used to prioritise candidates for analysis. Finally, we identify another axis-associated protein with a role in meiotic recombination. Data are available via ProteomeXchange with identifier PXD006042.
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Affiliation(s)
- Kim Osman
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
| | - Jianhua Yang
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
- Present address:
Faculty of Engineering and ComputingCoventry UniversityCoventryCV1 5FBUK
| | | | - Christophe Lambing
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
- Present address:
Department of Plant SciencesUniversity of CambridgeDowning StreetCambridgeCB2 3EAUK
| | - Stefan Heckmann
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
- Present address:
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK)OT Gatersleben, Corrensstrasse 3D‐06466Stadt SeelandGermany
| | - Elaine Howell
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
| | - Maria Cuacos
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
- Present address:
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK)OT Gatersleben, Corrensstrasse 3D‐06466Stadt SeelandGermany
| | | | - Gerhard Dürnberger
- IMP‐IMBA1030ViennaAustria
- Gregor Mendel Institute of Molecular Plant BiologyDr. Bohr‐Gasse 31030ViennaAustria
| | | | - Susan Armstrong
- School of BiosciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
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158
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Molecular Chaperones: Structure-Function Relationship and their Role in Protein Folding. REGULATION OF HEAT SHOCK PROTEIN RESPONSES 2018. [DOI: 10.1007/978-3-319-74715-6_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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159
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Jana N, Nanda S. Resorcylic acid lactones (RALs) and their structural congeners: recent advances in their biosynthesis, chemical synthesis and biology. NEW J CHEM 2018. [DOI: 10.1039/c8nj02534g] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Resorcylic acid lactones (RALs) are naturally occurring 14-membered macrolactones that constitute a class of polyketides derived from fungal metabolites and that possess significant and promising biological activity.
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Affiliation(s)
- Nandan Jana
- Department of Chemistry
- Indian Institute of Technology Kharagpur
- Kharagpur
- India
| | - Samik Nanda
- Department of Chemistry
- Indian Institute of Technology Kharagpur
- Kharagpur
- India
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160
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Sarno R, Vicq Y, Uematsu N, Luka M, Lapierre C, Carroll D, Bastianelli G, Serero A, Nicolas A. Programming sites of meiotic crossovers using Spo11 fusion proteins. Nucleic Acids Res 2017; 45:e164. [PMID: 28977556 PMCID: PMC5737382 DOI: 10.1093/nar/gkx739] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/17/2017] [Indexed: 12/05/2022] Open
Abstract
Meiotic recombination shapes the genetic diversity transmitted upon sexual reproduction. However, its non-random distribution along the chromosomes constrains the landscape of potential genetic combinations. For a variety of purposes, it is desirable to expand the natural repertoire by changing the distribution of crossovers in a wide range of eukaryotes. Toward this end, we report the local stimulation of meiotic recombination at a number of chromosomal sites by tethering the natural Spo11 protein to various DNA-binding modules: full-length DNA binding proteins, zinc fingers (ZFs), transcription activator-like effector (TALE) modules, and the CRISPR-Cas9 system. In the yeast Saccharomyces cerevisiae, each strategy is able to stimulate crossover frequencies in naturally recombination-cold regions. The binding and cleavage efficiency of the targeting Spo11 fusions (TSF) are variable, being dependent on the chromosomal regions and potential competition with endogenous factors. TSF-mediated genome interrogation distinguishes naturally recombination-cold regions that are flexible and can be warmed-up (gene promoters and coding sequences), from those that remain refractory (gene terminators and centromeres). These results describe new generic experimental strategies to increase the genetic diversity of gametes, which should prove useful in plant breeding and other applications.
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Affiliation(s)
- Roberta Sarno
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
| | - Yoan Vicq
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
| | - Norio Uematsu
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
| | - Marine Luka
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
| | - Clement Lapierre
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
| | - Dana Carroll
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA
| | | | - Alexandre Serero
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
| | - Alain Nicolas
- Institut Curie, PSL Research University, CNRS UMR3244, Recombination and Genetic Instability, Paris F-75005, France.,Sorbonne Universités, UPMC Université Paris 06, CNRS UMR3244, Paris F-75005, France
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161
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Yamada S, Kim S, Tischfield SE, Jasin M, Lange J, Keeney S. Genomic and chromatin features shaping meiotic double-strand break formation and repair in mice. Cell Cycle 2017; 16:1870-1884. [PMID: 28820351 PMCID: PMC5638367 DOI: 10.1080/15384101.2017.1361065] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/27/2017] [Accepted: 07/25/2017] [Indexed: 11/12/2022] Open
Abstract
The SPO11-generated DNA double-strand breaks (DSBs) that initiate meiotic recombination occur non-randomly across genomes, but mechanisms shaping their distribution and repair remain incompletely understood. Here, we expand on recent studies of nucleotide-resolution DSB maps in mouse spermatocytes. We find that trimethylation of histone H3 lysine 36 around DSB hotspots is highly correlated, both spatially and quantitatively, with trimethylation of H3 lysine 4, consistent with coordinated formation and action of both PRDM9-dependent histone modifications. In contrast, the DSB-responsive kinase ATM contributes independently of PRDM9 to controlling hotspot activity, and combined action of ATM and PRDM9 can explain nearly two-thirds of the variation in DSB frequency between hotspots. DSBs were modestly underrepresented in most repetitive sequences such as segmental duplications and transposons. Nonetheless, numerous DSBs form within repetitive sequences in each meiosis and some classes of repeats are preferentially targeted. Implications of these findings are discussed for evolution of PRDM9 and its role in hybrid strain sterility in mice. Finally, we document the relationship between mouse strain-specific DNA sequence variants within PRDM9 recognition motifs and attendant differences in recombination outcomes. Our results provide further insights into the complex web of factors that influence meiotic recombination patterns.
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Affiliation(s)
- Shintaro Yamada
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Seoyoung Kim
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Sam E. Tischfield
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Tri-Institutional Training Program in Computational Biology and Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Maria Jasin
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Julian Lange
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Scott Keeney
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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162
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MTOPVIB interacts with AtPRD1 and plays important roles in formation of meiotic DNA double-strand breaks in Arabidopsis. Sci Rep 2017; 7:10007. [PMID: 28855712 PMCID: PMC5577129 DOI: 10.1038/s41598-017-10270-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 07/28/2017] [Indexed: 12/19/2022] Open
Abstract
Meiotic recombination is initiated from the formation of DNA double-strand breaks (DSBs). In Arabidopsis, several proteins, such as AtPRD1, AtPRD2, AtPRD3, AtDFO and topoisomerase (Topo) VI-like complex, have been identified as playing important roles in DSB formation. Topo VI-like complex in Arabidopsis may consist of subunit A (Topo VIA: AtSPO11-1 and AtSPO11-2) and subunit B (Topo VIB: MTOPVIB). Little is known about their roles in Arabidopsis DSB formation. Here, we report on the characterization of the MTOPVIB gene using the Arabidopsis mutant alleles mtopVIB-2 and mtopVIB-3, which were defective in DSB formation. mtopVIB-3 exhibited abortion in embryo sac and pollen development, leading to a significant reduction in fertility. The mtopVIB mutations affected the homologous chromosome synapsis and recombination. MTOPVIB could interact with Topo VIA proteins AtSPO11-1 and AtSPO11-2. AtPRD1 interacted directly with Topo VI–like proteins. AtPRD1 also could interact with AtPRD3 and AtDFO. The results indicated that AtPRD1 may act as a bridge protein to interact with AtPRD3 and AtDFO, and interact directly with the Topo VI-like proteins MTOPVIB, AtSPO11-1 and AtSPO11-2 to take part in DSB formation in Arabidopsis.
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163
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Markowitz TE, Suarez D, Blitzblau HG, Patel NJ, Markhard AL, MacQueen AJ, Hochwagen A. Reduced dosage of the chromosome axis factor Red1 selectively disrupts the meiotic recombination checkpoint in Saccharomyces cerevisiae. PLoS Genet 2017; 13:e1006928. [PMID: 28746375 PMCID: PMC5549997 DOI: 10.1371/journal.pgen.1006928] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 08/09/2017] [Accepted: 07/17/2017] [Indexed: 11/18/2022] Open
Abstract
Meiotic chromosomes assemble characteristic "axial element" structures that are essential for fertility and provide the chromosomal context for meiotic recombination, synapsis and checkpoint signaling. Whether these meiotic processes are equally dependent on axial element integrity has remained unclear. Here, we investigated this question in S. cerevisiae using the putative condensin allele ycs4S. We show that the severe axial element assembly defects of this allele are explained by a linked mutation in the promoter of the major axial element gene RED1 that reduces Red1 protein levels to 20-25% of wild type. Intriguingly, the Red1 levels of ycs4S mutants support meiotic processes linked to axis integrity, including DNA double-strand break formation and deposition of the synapsis protein Zip1, at levels that permit 70% gamete survival. By contrast, the ability to elicit a meiotic checkpoint arrest is completely eliminated. This selective loss of checkpoint function is supported by a RED1 dosage series and is associated with the loss of most of the cytologically detectable Red1 from the axial element. Our results indicate separable roles for Red1 in building the structural axis of meiotic chromosomes and mounting a sustained recombination checkpoint response.
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Affiliation(s)
- Tovah E. Markowitz
- Department of Biology; New York University; New York, NY; United States of America
| | - Daniel Suarez
- Department of Biology; New York University; New York, NY; United States of America
| | - Hannah G. Blitzblau
- Whitehead Institute for Biomedical Research; Cambridge, MA; United States of America
| | - Neem J. Patel
- Department of Biology; New York University; New York, NY; United States of America
| | - Andrew L. Markhard
- Whitehead Institute for Biomedical Research; Cambridge, MA; United States of America
| | - Amy J. MacQueen
- Department of Molecular Biology and Biochemistry; Wesleyan University; Middletown, CT; United States of America
| | - Andreas Hochwagen
- Department of Biology; New York University; New York, NY; United States of America
- Whitehead Institute for Biomedical Research; Cambridge, MA; United States of America
- * E-mail:
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164
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Fukui K, Iino H, Baba S, Kumasaka T, Kuramitsu S, Yano T. Crystal structure and DNA-binding property of the ATPase domain of bacterial mismatch repair endonuclease MutL from Aquifex aeolicus. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1178-1187. [PMID: 28668638 DOI: 10.1016/j.bbapap.2017.06.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 01/06/2023]
Abstract
DNA mismatch repair (MMR) system corrects mismatched bases that are generated mainly by DNA replication errors. The repair system excises the error-containing single-stranded region and enables the re-synthesis of the strand. In the early reactions of MMR, MutL endonuclease incises the newly-synthesized/error-containing strand of the duplex to initiate the downstream excision reaction. MutL endonuclease consists of the N-terminal ATPase and C-terminal endonuclease domains. In this study, we report the crystal structure of the ATPase domain of MutL endonuclease from Aquifex aeolicus. The overall structure of the domain was similar to those of human MutL homologs and Escherichia coli MutL, although E. coli MutL has no endonuclease activity. The ATPase domain was comprised of two subdomains: the N-terminal ATP-binding subdomain and the C-terminal α-β sandwich subdomain. Site-directed mutagenesis experiment identified DNA-interacting eight basic amino acid residues, which were distributed across both the two subdomains and formed a DNA-binding cleft. Docking simulation between the structures of the ATPase and endonuclease domains generated a reliable model structure for the full-length A. aeolicus MutL, which satisfies our previous result of small-angle X-ray scattering analysis. On the basis of the model structure and further experimental results, we concluded that the two separate DNA-binding sites in the full-length A. aeolicus MutL simultaneously bind a dsDNA molecule.
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Affiliation(s)
- Kenji Fukui
- Department of Biochemistry, Osaka Medical College, 2-7 Daigakumachi, Takatsuki, Osaka 569-8686, Japan.
| | - Hitoshi Iino
- RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo-cho, Sayo-Gun, Hyogo 679-5148, Japan
| | - Seiki Baba
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Kouto, Sayo, Hyogo 679-5198, Japan
| | - Takashi Kumasaka
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, Kouto, Sayo, Hyogo 679-5198, Japan
| | - Seiki Kuramitsu
- Department of Biological Sciences, Osaka University, 1-1 Machikaneyamacho, Toyonaka, Osaka 560-0043, Japan
| | - Takato Yano
- Department of Biochemistry, Osaka Medical College, 2-7 Daigakumachi, Takatsuki, Osaka 569-8686, Japan.
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165
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So similar yet so different: The two ends of a double strand break. Mutat Res 2017; 809:70-80. [PMID: 28693746 DOI: 10.1016/j.mrfmmm.2017.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/21/2017] [Accepted: 06/26/2017] [Indexed: 11/22/2022]
Abstract
Homologous recombination (HR) is essential for ensuring proper segregation of chromosomes in the first round of meiotic division. HR is also crucial for preserving genomic integrity of somatic cells due to its ability to rescue collapsed replication forks and eliminate deleterious DNA lesions, such as double-strand breaks (DSBs), interstrand crosslinks, and single-strand DNA gaps. Here, we review the early steps of HR (homology search and strand exchange), focusing on the roles of the two ends of a DSB. A detailed overview of the basic HR machinery and its mechanism for template selection and capture of duplex DNA via strand exchange is provided. Roles of proteins involved in these steps are discussed in both mitotic and meiotic HR. Central to this review is the hypothesis, which suggests that in meiosis, HR begins with a symmetrical DSB, but the symmetry is quickly lost with the two ends assuming different roles; it argues that this disparity of the two ends is essential for regulation of HR in meiosis and successful production of haploid gametes. We also propose a possible evolutionary reason for the asymmetry of the ends in HR.
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166
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Kshirsagar R, Ghodke I, Muniyappa K. Saccharomyces cerevisiae Red1 protein exhibits nonhomologous DNA end-joining activity and potentiates Hop1-promoted pairing of double-stranded DNA. J Biol Chem 2017. [PMID: 28642366 DOI: 10.1074/jbc.m117.796425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Elucidation of the function of synaptonemal complex (SC) in Saccharomyces cerevisiae has mainly focused on in vivo analysis of recombination-defective meiotic mutants. Consequently, significant gaps remain in the mechanistic understanding of the activities of various SC proteins and the functional relationships among them. S. cerevisiae Hop1 and Red1 are essential structural components of the SC axial/lateral elements. Previous studies have demonstrated that Hop1 is a structure-selective DNA-binding protein exhibiting high affinity for the Holliday junction and promoting DNA bridging, condensation, and pairing between double-stranded DNA molecules. However, the exact mode of action of Red1 remains unclear, although it is known to interact with Hop1 and to suppress the spore viability defects of hop1 mutant alleles. Here, we report the purification and functional characterization of the full-length Red1 protein. Our results revealed that Red1 forms a stable complex with Hop1 in vitro and provided quantitative insights into their physical interactions. Mechanistically, Red1 preferentially associated with the Holliday junction and 3-way junction rather than with single- or double-stranded DNA with overhangs. Although Hop1 and Red1 exhibited similar binding affinities toward several DNA substrates, the two proteins displayed some significant differences. Notably, Red1, by itself, lacked DNA-pairing ability; however, it potentiated Hop1-promoted intermolecular pairing between double-stranded DNA molecules. Moreover, Red1 exhibited nonhomologous DNA end-joining activity, thus revealing an unexpected role for Red1 in recombination-based DNA repair. Collectively, this study presents the first direct insights into Red1's mode of action and into the mechanism underlying its role in chromosome synapsis and recombination.
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Affiliation(s)
- Rucha Kshirsagar
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Indrajeet Ghodke
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - K Muniyappa
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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167
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Robert T, de Massy B, Grelon M. [TopoVIL : a molecular scissor essential for reproduction]. Med Sci (Paris) 2017; 33:512-518. [PMID: 28612727 DOI: 10.1051/medsci/20173305015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
During sexual reproduction haploid gametes are generated out of diploid mother cells. This ploidy reduction is accomplished during meiosis and, in most species, relies on the occurrence of homologous recombination that is triggered by the induction of a large number of DNA double strand breaks (DSBs). The mechanism by which such DSBs are generated without provoking massive DNA breakdown in gamete mother cells is still poorly understood. However, the recent characterisation, in plants and in mammals, of a new component of the meiotic DSB forming machinery, defining a meiotic-specific TOPOVIB-Like protein family, has established a clear connection between the meiotic DSB activity and topoisomerases, enzymes that modify the DNA topology by introducing transient DSBs.
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Affiliation(s)
- Thomas Robert
- Institut de Génétique Humaine, UMR9002 CNRS-Université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier Cedex 05, France
| | - Bernard de Massy
- Institut de Génétique Humaine, UMR9002 CNRS-Université de Montpellier, 141, rue de la Cardonille, 34396 Montpellier Cedex 05, France
| | - Mathilde Grelon
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, RD10, 78026 Versailles Cedex, France
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168
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Functional characterization of the meiosis-specific DNA double-strand break inducing factor SPO-11 from C. elegans. Sci Rep 2017; 7:2370. [PMID: 28539630 PMCID: PMC5443798 DOI: 10.1038/s41598-017-02641-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/13/2017] [Indexed: 11/17/2022] Open
Abstract
The programmed induction of meiotic DNA double-strand breaks (DSBs) by the evolutionarily conserved SPO-11 protein, which is structurally related to archaeal Topo VIA topoisomerases, triggers meiotic recombination. Identification of several meiosis-specific factors that are required for SPO-11-mediated DSB formation raises the question whether SPO-11 alone can cleave DNA. Here, we have developed procedures to express and purify C. elegans SPO-11 in a soluble, untagged, and monodispersed form. Our biochemical and biophysical analyses demonstrate that SPO-11 is monomeric and binds DNA, double-stranded DNA in particular. Importantly, SPO-11 does not exhibit DNA cleavage activity under a wide range of reaction conditions, suggesting that co-factors are needed for DSB induction activity. Our SPO-11 purification system and the findings reported herein should facilitate future mechanistic studies directed at delineating the mechanism of action of the SPO-11 ensemble in meiotic DSB formation.
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169
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Claeys Bouuaert C, Keeney S. Distinct DNA-binding surfaces in the ATPase and linker domains of MutLγ determine its substrate specificities and exert separable functions in meiotic recombination and mismatch repair. PLoS Genet 2017; 13:e1006722. [PMID: 28505149 PMCID: PMC5448812 DOI: 10.1371/journal.pgen.1006722] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 05/30/2017] [Accepted: 03/29/2017] [Indexed: 11/18/2022] Open
Abstract
Mlh1-Mlh3 (MutLγ) is a mismatch repair factor with a central role in formation of meiotic crossovers, presumably through resolution of double Holliday junctions. MutLγ has DNA-binding, nuclease, and ATPase activities, but how these relate to one another and to in vivo functions are unclear. Here, we combine biochemical and genetic analyses to characterize Saccharomyces cerevisiae MutLγ. Limited proteolysis and atomic force microscopy showed that purified recombinant MutLγ undergoes ATP-driven conformational changes. In vitro, MutLγ displayed separable DNA-binding activities toward Holliday junctions (HJ) and, surprisingly, single-stranded DNA (ssDNA), which was not predicted from current models. MutLγ bound DNA cooperatively, could bind multiple substrates simultaneously, and formed higher-order complexes. FeBABE hydroxyl radical footprinting indicated that the DNA-binding interfaces of MutLγ for ssDNA and HJ substrates only partially overlap. Most contacts with HJ substrates were located in the linker regions of MutLγ, whereas ssDNA contacts mapped within linker regions as well as the N-terminal ATPase domains. Using yeast genetic assays for mismatch repair and meiotic recombination, we found that mutations within different DNA-binding surfaces exert separable effects in vivo. For example, mutations within the Mlh1 linker conferred little or no meiotic phenotype but led to mismatch repair deficiency. Interestingly, mutations in the N-terminal domain of Mlh1 caused a stronger meiotic defect than mlh1Δ, suggesting that the mutant proteins retain an activity that interferes with alternative recombination pathways. Furthermore, mlh3Δ caused more chromosome missegregation than mlh1Δ, whereas mlh1Δ but not mlh3Δ partially alleviated meiotic defects of msh5Δ mutants. These findings illustrate functional differences between Mlh1 and Mlh3 during meiosis and suggest that their absence impinges on chromosome segregation not only via reduced formation of crossovers. Taken together, our results offer insights into the structure-function relationships of the MutLγ complex and reveal unanticipated genetic relationships between components of the meiotic recombination machinery.
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Affiliation(s)
- Corentin Claeys Bouuaert
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center and Howard Hughes Medical Institute, New York, New York, United States of America
- * E-mail: (C.C.B.); (S.K.)
| | - Scott Keeney
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center and Howard Hughes Medical Institute, New York, New York, United States of America
- * E-mail: (C.C.B.); (S.K.)
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170
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Nadarajan S, Lambert TJ, Altendorfer E, Gao J, Blower MD, Waters JC, Colaiácovo MP. Polo-like kinase-dependent phosphorylation of the synaptonemal complex protein SYP-4 regulates double-strand break formation through a negative feedback loop. eLife 2017; 6. [PMID: 28346135 PMCID: PMC5423773 DOI: 10.7554/elife.23437] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/23/2017] [Indexed: 12/22/2022] Open
Abstract
The synaptonemal complex (SC) is an ultrastructurally conserved proteinaceous structure that holds homologous chromosomes together and is required for the stabilization of pairing interactions and the completion of crossover (CO) formation between homologs during meiosis I. Here, we identify a novel role for a central region component of the SC, SYP-4, in negatively regulating formation of recombination-initiating double-strand breaks (DSBs) via a feedback loop triggered by crossover designation in C. elegans. We found that SYP-4 is phosphorylated dependent on Polo-like kinases PLK-1/2. SYP-4 phosphorylation depends on DSB formation and crossover designation, is required for stabilizing the SC in pachytene by switching the central region of the SC from a more dynamic to a less dynamic state, and negatively regulates DSB formation. We propose a model in which Polo-like kinases recognize crossover designation and phosphorylate SYP-4 thereby stabilizing the SC and making chromosomes less permissive for further DSB formation.
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Affiliation(s)
| | - Talley J Lambert
- Department of Cell Biology, Harvard Medical School, Boston, United States
| | | | - Jinmin Gao
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Michael D Blower
- Department of Genetics, Harvard Medical School, Boston, United States.,Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Jennifer C Waters
- Department of Cell Biology, Harvard Medical School, Boston, United States
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171
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Pattabiraman D, Roelens B, Woglar A, Villeneuve AM. Meiotic recombination modulates the structure and dynamics of the synaptonemal complex during C. elegans meiosis. PLoS Genet 2017; 13:e1006670. [PMID: 28339470 PMCID: PMC5384771 DOI: 10.1371/journal.pgen.1006670] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/07/2017] [Accepted: 03/06/2017] [Indexed: 12/04/2022] Open
Abstract
During meiotic prophase, a structure called the synaptonemal complex (SC) assembles at the interface between aligned pairs of homologous chromosomes, and crossover recombination events occur between their DNA molecules. Here we investigate the inter-relationships between these two hallmark features of the meiotic program in the nematode C. elegans, revealing dynamic properties of the SC that are modulated by recombination. We demonstrate that the SC incorporates new subunits and switches from a more highly dynamic/labile state to a more stable state as germ cells progress through the pachytene stage of meiotic prophase. We further show that the more dynamic state of the SC is prolonged in mutants where meiotic recombination is impaired. Moreover, in meiotic mutants where recombination intermediates are present in limiting numbers, SC central region subunits become preferentially stabilized on the subset of chromosome pairs that harbor a site where pro-crossover factors COSA-1 and MutSγ are concentrated. Polo-like kinase PLK-2 becomes preferentially localized to the SCs of chromosome pairs harboring recombination sites prior to the enrichment of SC central region proteins on such chromosomes, and PLK-2 is required for this enrichment to occur. Further, late pachytene nuclei in a plk-2 mutant exhibit the more highly dynamic SC state. Together our data demonstrate that crossover recombination events elicit chromosome-autonomous stabilizing effects on the SC and implicate PLK-2 in this process. We discuss how this recombination-triggered modulation of SC state might contribute to regulatory mechanisms that operate during meiosis to ensure the formation of crossovers while at the same time limiting their numbers.
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Affiliation(s)
- Divya Pattabiraman
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Baptiste Roelens
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Alexander Woglar
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, California, United States of America
| | - Anne M. Villeneuve
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, California, United States of America
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172
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Advances in the Chemistry of Natural and Semisynthetic Topoisomerase I/II Inhibitors. STUDIES IN NATURAL PRODUCTS CHEMISTRY 2017. [DOI: 10.1016/b978-0-444-63929-5.00002-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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173
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Grégoire MC, Massonneau J, Leduc F, Arguin M, Brazeau MA, Boissonneault G. Quantification and genome-wide mapping of DNA double-strand breaks. DNA Repair (Amst) 2016; 48:63-68. [DOI: 10.1016/j.dnarep.2016.10.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/19/2016] [Indexed: 11/26/2022]
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174
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Anand R, Ranjha L, Cannavo E, Cejka P. Phosphorylated CtIP Functions as a Co-factor of the MRE11-RAD50-NBS1 Endonuclease in DNA End Resection. Mol Cell 2016; 64:940-950. [PMID: 27889449 DOI: 10.1016/j.molcel.2016.10.017] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/26/2016] [Accepted: 10/13/2016] [Indexed: 12/26/2022]
Abstract
To repair a DNA double-strand break (DSB) by homologous recombination (HR), the 5'-terminated strand of the DSB must be resected. The human MRE11-RAD50-NBS1 (MRN) and CtIP proteins were implicated in the initiation of DNA end resection, but the underlying mechanism remained undefined. Here, we show that CtIP is a co-factor of the MRE11 endonuclease activity within the MRN complex. This function is absolutely dependent on CtIP phosphorylation that includes the key cyclin-dependent kinase target motif at Thr-847. Unlike in yeast, where the Xrs2/NBS1 subunit is dispensable in vitro, NBS1 is absolutely required in the human system. The MRE11 endonuclease in conjunction with RAD50, NBS1, and phosphorylated CtIP preferentially cleaves 5'-terminated DNA strands near DSBs. Our results define the initial step of HR that is particularly relevant for the processing of DSBs bearing protein blocks.
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Affiliation(s)
- Roopesh Anand
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Lepakshi Ranjha
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Elda Cannavo
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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175
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Xue Z, Li Y, Zhang L, Shi W, Zhang C, Feng M, Zhang F, Tang D, Yu H, Gu M, Cheng Z. OsMTOPVIB Promotes Meiotic DNA Double-Strand Break Formation in Rice. MOLECULAR PLANT 2016; 9:1535-1538. [PMID: 27456761 DOI: 10.1016/j.molp.2016.07.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/13/2016] [Accepted: 07/15/2016] [Indexed: 05/25/2023]
Affiliation(s)
- Zhihui Xue
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yafei Li
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lei Zhang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenqing Shi
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chao Zhang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Mengshi Feng
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Fanfan Zhang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ding Tang
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hengxiu Yu
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Minghong Gu
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province/Key Laboratory of Plant Functional Genomics of Ministry of Education, Yangzhou University, Yangzhou 225009, China
| | - Zhukuan Cheng
- State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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176
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Fu M, Wang C, Xue F, Higgins J, Chen M, Zhang D, Liang W. The DNA Topoisomerase VI-B Subunit OsMTOPVIB Is Essential for Meiotic Recombination Initiation in Rice. MOLECULAR PLANT 2016; 9:1539-1541. [PMID: 27477684 DOI: 10.1016/j.molp.2016.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 05/25/2023]
Affiliation(s)
- Ming Fu
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China
| | - Chong Wang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China
| | - Feiyang Xue
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China
| | - James Higgins
- Deparment of Genetics, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Mingjiao Chen
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China; School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Urrbrae, SA 5064, Australia
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China.
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177
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Finsterbusch F, Ravindranathan R, Dereli I, Stanzione M, Tränkner D, Tóth A. Alignment of Homologous Chromosomes and Effective Repair of Programmed DNA Double-Strand Breaks during Mouse Meiosis Require the Minichromosome Maintenance Domain Containing 2 (MCMDC2) Protein. PLoS Genet 2016; 12:e1006393. [PMID: 27760146 PMCID: PMC5070785 DOI: 10.1371/journal.pgen.1006393] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 09/28/2016] [Indexed: 02/06/2023] Open
Abstract
Orderly chromosome segregation during the first meiotic division requires meiotic recombination to form crossovers between homologous chromosomes (homologues). Members of the minichromosome maintenance (MCM) helicase family have been implicated in meiotic recombination. In addition, they have roles in initiation of DNA replication, DNA mismatch repair and mitotic DNA double-strand break repair. Here, we addressed the function of MCMDC2, an atypical yet conserved MCM protein, whose function in vertebrates has not been reported. While we did not find an important role for MCMDC2 in mitotically dividing cells, our work revealed that MCMDC2 is essential for fertility in both sexes due to a crucial function in meiotic recombination. Meiotic recombination begins with the introduction of DNA double-strand breaks into the genome. DNA ends at break sites are resected. The resultant 3-prime single-stranded DNA overhangs recruit RAD51 and DMC1 recombinases that promote the invasion of homologous duplex DNAs by the resected DNA ends. Multiple strand invasions on each chromosome promote the alignment of homologous chromosomes, which is a prerequisite for inter-homologue crossover formation during meiosis. We found that although DNA ends at break sites were evidently resected, and they recruited RAD51 and DMC1 recombinases, these recombinases were ineffective in promoting alignment of homologous chromosomes in the absence of MCMDC2. Consequently, RAD51 and DMC1 foci, which are thought to mark early recombination intermediates, were abnormally persistent in Mcmdc2-/- meiocytes. Importantly, the strand invasion stabilizing MSH4 protein, which marks more advanced recombination intermediates, did not efficiently form foci in Mcmdc2-/- meiocytes. Thus, our work suggests that MCMDC2 plays an important role in either the formation, or the stabilization, of DNA strand invasion events that promote homologue alignment and provide the basis for inter-homologue crossover formation during meiotic recombination.
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Affiliation(s)
| | - Ramya Ravindranathan
- Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Dresden, Germany
| | - Ihsan Dereli
- Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Dresden, Germany
| | - Marcello Stanzione
- Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Dresden, Germany
| | - Daniel Tränkner
- Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Dresden, Germany
| | - Attila Tóth
- Institute of Physiological Chemistry, Medical Faculty of TU Dresden, Dresden, Germany
- * E-mail:
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178
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Meiotic DNA break formation requires the unsynapsed chromosome axis-binding protein IHO1 (CCDC36) in mice. Nat Cell Biol 2016; 18:1208-1220. [PMID: 27723721 DOI: 10.1038/ncb3417] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 09/06/2016] [Indexed: 12/15/2022]
Abstract
DNA double-strand breaks (DSBs) are induced by SPO11 during meiosis to initiate recombination-mediated pairing and synapsis of homologous chromosomes. Germline genome integrity requires spatiotemporal control of DSB formation, which involves the proteinaceous chromosome axis along the core of each meiotic chromosome. In particular, a component of unsynapsed axes, HORMAD1, promotes DSB formation in unsynapsed regions where DSB formation must occur to ensure completion of synapsis. Despite its importance, the underlying mechanism has remained elusive. We identify CCDC36 as a direct interactor of HORMAD1 (IHO1) that is essential for DSB formation. Underpinning this function, IHO1 and conserved SPO11-auxiliary proteins MEI4 and REC114 assemble chromatin-bound recombinosomes that are predicted activators of DSB formation. HORMAD1 is needed for robust recruitment of IHO1 to unsynapsed axes and efficient formation and/or stabilization of these recombinosomes. Thus, we propose that HORMAD1-IHO1 interaction provides a mechanism for the selective promotion of DSB formation along unsynapsed chromosome axes.
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179
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A Surveillance System Ensures Crossover Formation in C. elegans. Curr Biol 2016; 26:2873-2884. [PMID: 27720619 DOI: 10.1016/j.cub.2016.09.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/27/2016] [Accepted: 09/06/2016] [Indexed: 11/23/2022]
Abstract
Crossover (CO) recombination creates a physical connection between homologs that promotes their proper segregation at meiosis I (MI). Failure to realize an obligate CO causes homologs to attach independently to the MI spindle and separate randomly, leading to nondisjunction. However, mechanisms that determine whether homolog pairs have received crossovers remain mysterious. Here we describe a surveillance system in C. elegans that monitors recombination intermediates and couples their formation to meiotic progression. Recombination intermediates are required to activate the system, which then delays further processing if crossover precursors are lacking on even one chromosome. The synaptonemal complex, a specialized, proteinaceous structure connecting homologous chromosomes, is stabilized in cis on chromosomes that receive a crossover and is destabilized on those lacking crossovers, a process that is dependent on the function of the polo-like kinase PLK-2. These results reveal a new layer of communication between crossover-committed intermediates and the synaptonemal complex that functions as a cis-acting, obligate, crossover-counting mechanism.
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180
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P31comet, a member of the synaptonemal complex, participates in meiotic DSB formation in rice. Proc Natl Acad Sci U S A 2016; 113:10577-82. [PMID: 27601671 DOI: 10.1073/pnas.1607334113] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The human mitotic arrest-deficient 2 (Mad2) binding protein p31(comet) participates in the spindle checkpoint and coordinates cell cycle events in mitosis although its function in meiosis remains unknown in all organisms. Here, we reveal P31(comet) as a synaptonemal complex (SC) protein in rice (Oryza sativa L.). In p31(comet), homologous pairing and synapsis are eliminated, leading to the homologous nondisjunction and complete sterility. The failure in loading of histone H2AX phosphorylation (γH2AX) in p31(comet), together with the suppressed chromosome fragmentation in rice completion of meiotic recombination 1 (com1) p31(comet) and radiation sensitive 51c (rad51c) p31(comet) double mutants, indicates that P31(comet) plays an essential role in double-strand break (DSB) formation. Interestingly, the dynamic colocalization pattern between P31(comet) and ZEP1 (a transverse filament protein of SC) by immunostaining, as well as the interaction between P31(comet) and CENTRAL REGION COMPONENT 1 (CRC1) in yeast two-hybrid assays, suggests possible involvement of P31(comet) in SC installation. Together, these data indicate that P31(comet) plays a key role in DSB formation and SC installation, mainly through its cooperation with CRC1.
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181
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Bigalke JM, Heldwein EE. Have NEC Coat, Will Travel: Structural Basis of Membrane Budding During Nuclear Egress in Herpesviruses. Adv Virus Res 2016; 97:107-141. [PMID: 28057257 DOI: 10.1016/bs.aivir.2016.07.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Herpesviruses are unusual among enveloped viruses because they bud twice yet acquire a single envelope. Furthermore, unlike other DNA viruses that replicate in the nucleus, herpesviruses do not exit it by passing through the nuclear pores or by rupturing the nuclear envelope. Instead, herpesviruses have a complex mechanism of nuclear escape whereby nascent capsids bud at the inner nuclear membrane to form perinuclear virions that subsequently fuse with the outer nuclear membrane, releasing capsids into the cytosol. This makes them some of the very few known viruses that bud into the nuclear envelope. The envelope acquired during nuclear budding does not end up in the mature viral particle but instead allows the capsid to translocate from the nucleus into the cytosol. The viral nuclear egress complex (NEC) is a critical player in the nuclear egress, yet its function and mechanism have remained enigmatic. Recent studies have demonstrated that the NEC buds membranes without the help of other proteins by forming a honeycomb coat, which established the NEC as the first virally encoded budding machine that operates at the nuclear, as opposed to cytoplasmic, membrane. This review discusses our current understanding of the NEC budding mechanism, with the emphasis on studies that illuminated the structure of the NEC coat and its role in capsid budding during herpesvirus nuclear escape.
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Affiliation(s)
- J M Bigalke
- Tufts University School of Medicine, Boston, MA, United States
| | - E E Heldwein
- Tufts University School of Medicine, Boston, MA, United States.
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182
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Pearl LH. Review: The HSP90 molecular chaperone-an enigmatic ATPase. Biopolymers 2016; 105:594-607. [PMID: 26991466 PMCID: PMC4879513 DOI: 10.1002/bip.22835] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/09/2016] [Accepted: 03/12/2016] [Indexed: 12/16/2022]
Abstract
The HSP90 molecular chaperone is involved in the activation and cellular stabilization of a range of 'client' proteins, of which oncogenic protein kinases and nuclear steroid hormone receptors are of particular biomedical significance. Work over the last two decades has revealed a conformational cycle critical to the biological function of HSP90, coupled to an inherent ATPase activity that is regulated and manipulated by many of the co-chaperones proteins with which it collaborates. Pharmacological inhibition of HSP90 ATPase activity results in degradation of client proteins in vivo, and is a promising target for development of new cancer therapeutics. Despite this, the actual function that HSP90s conformationally-coupled ATPase activity provides in its biological role as a molecular chaperone remains obscure. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 594-607, 2016.
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Affiliation(s)
- Laurence H Pearl
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QR, UK
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183
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Huang J, Copenhaver GP, Ma H, Wang Y. New insights into the role of DNA synthesis in meiotic recombination. Sci Bull (Beijing) 2016. [DOI: 10.1007/s11434-016-1126-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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184
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185
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Robert T, Vrielynck N, Mézard C, de Massy B, Grelon M. A new light on the meiotic DSB catalytic complex. Semin Cell Dev Biol 2016; 54:165-76. [DOI: 10.1016/j.semcdb.2016.02.025] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/22/2016] [Indexed: 11/30/2022]
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186
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Harris CJ, Husmann D, Liu W, Kasmi FE, Wang H, Papikian A, Pastor WA, Moissiard G, Vashisht AA, Dangl JL, Wohlschlegel JA, Jacobsen SE. Arabidopsis AtMORC4 and AtMORC7 Form Nuclear Bodies and Repress a Large Number of Protein-Coding Genes. PLoS Genet 2016; 12:e1005998. [PMID: 27171361 PMCID: PMC4865129 DOI: 10.1371/journal.pgen.1005998] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/30/2016] [Indexed: 12/30/2022] Open
Abstract
The MORC family of GHKL ATPases are an enigmatic class of proteins with diverse chromatin related functions. In Arabidopsis, AtMORC1, AtMORC2, and AtMORC6 act together in heterodimeric complexes to mediate transcriptional silencing of methylated DNA elements. Here, we studied Arabidopsis AtMORC4 and AtMORC7. We found that, in contrast to AtMORC1,2,6, they act to suppress a wide set of non-methylated protein-coding genes that are enriched for those involved in pathogen response. Furthermore, atmorc4 atmorc7 double mutants show a pathogen response phenotype. We found that AtMORC4 and AtMORC7 form homomeric complexes in vivo and are concentrated in discrete nuclear bodies adjacent to chromocenters. Analysis of an atmorc1,2,4,5,6,7 hextuple mutant demonstrates that transcriptional de-repression is largely uncoupled from changes in DNA methylation in plants devoid of MORC function. However, we also uncover a requirement for MORC in both DNA methylation and silencing at a small but distinct subset of RNA-directed DNA methylation target loci. These regions are characterized by poised transcriptional potential and a low density of sites for symmetric cytosine methylation. These results provide insight into the biological function of MORC proteins in higher eukaryotes.
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Affiliation(s)
- C. Jake Harris
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Dylan Husmann
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Wanlu Liu
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Farid El Kasmi
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Haifeng Wang
- Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology (HIST), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Ashot Papikian
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - William A. Pastor
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Guillaume Moissiard
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Ajay A. Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Jeffery L. Dangl
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - James A. Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, United States of America
| | - Steven E. Jacobsen
- Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California, United States of America
- Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, California, United States of America
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187
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Abstract
The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is initiated by nucleolytic degradation of the 5'-terminated strands in a process termed end resection. End resection generates 3'-single-stranded DNA tails, substrates for Rad51 to catalyze homologous pairing and DNA strand exchange, and for activation of the DNA damage checkpoint. The commonly accepted view is that end resection occurs by a two-step mechanism. In the first step, Sae2/CtIP activates the Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex to endonucleolytically cleave the 5'-terminated DNA strands close to break ends, and in the second step Exo1 and/or Dna2 nucleases extend the resected tracts to produce long 3'-ssDNA-tailed intermediates. Initiation of resection commits a cell to repair a DSB by HR because long ssDNA overhangs are poor substrates for non-homologous end joining (NHEJ). Thus, the initiation of end resection has emerged as a critical control point for repair pathway choice. Here, I review recent studies on the mechanism of end resection and how this process is regulated to ensure the most appropriate repair outcome.
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Affiliation(s)
- Lorraine S Symington
- a Department of Microbiology & Immunology , Columbia University Medical Center , New York , USA
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188
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The epigenetic regulator Smchd1 contains a functional GHKL-type ATPase domain. Biochem J 2016; 473:1733-44. [PMID: 27059856 DOI: 10.1042/bcj20160189] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 04/08/2016] [Indexed: 12/11/2022]
Abstract
Structural maintenance of chromosomes flexible hinge domain containing 1 (Smchd1) is an epigenetic regulator that plays critical roles in gene regulation during development. Mutations in SMCHD1 were recently implicated in the pathogenesis of facioscapulohumeral muscular dystrophy (FSHD), although the mechanistic basis remains of outstanding interest. We have previously shown that Smchd1 associates with chromatin via its homodimeric C-terminal hinge domain, yet little is known about the function of the putative GHKL (gyrase, Hsp90, histidine kinase, MutL)-type ATPase domain at its N-terminus. To formally assess the structure and function of Smchd1's ATPase domain, we have generated recombinant proteins encompassing the predicted ATPase domain and the adjacent region. Here, we show that the Smchd1 N-terminal region exists as a monomer and adopts a conformation resembling that of monomeric full-length heat shock protein 90 (Hsp90) protein in solution, even though the two proteins share only ∼8% overall sequence identity. Despite being monomeric, the N-terminal region of Smchd1 exhibits ATPase activity, which can be antagonized by the reaction product, ADP, or the Hsp90 inhibitor, radicicol, at a nanomolar concentration. Interestingly, introduction of an analogous mutation to that identified in SMCHD1 of an FSHD patient compromised protein stability, suggesting a possible molecular basis for loss of protein function and pathogenesis. Together, these results reveal important structure-function characteristics of Smchd1 that may underpin its mechanistic action at the chromatin level.
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189
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Kobayashi W, Takaku M, Machida S, Tachiwana H, Maehara K, Ohkawa Y, Kurumizaka H. Chromatin architecture may dictate the target site for DMC1, but not for RAD51, during homologous pairing. Sci Rep 2016; 6:24228. [PMID: 27052786 PMCID: PMC4823753 DOI: 10.1038/srep24228] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 03/22/2016] [Indexed: 01/17/2023] Open
Abstract
In eukaryotes, genomic DNA is compacted as chromatin, in which histones and DNA form the nucleosome as the basic unit. DMC1 and RAD51 are essential eukaryotic recombinases that mediate homologous chromosome pairing during homologous recombination. However, the means by which these two recombinases distinctly function in chromatin have remained elusive. Here we found that, in chromatin, the human DMC1-single-stranded DNA complex bypasses binding to the nucleosome, and preferentially promotes homologous pairing at the nucleosome-depleted regions. Consistently, DMC1 forms ternary complex recombination intermediates with the nucleosome-free DNA or the nucleosome-depleted DNA region. Surprisingly, removal of the histone tails improperly enhances the nucleosome binding by DMC1. In contrast, RAD51 does not specifically target the nucleosome-depleted region in chromatin. These are the first demonstrations that the chromatin architecture specifies the sites to promote the homologous recombination reaction by DMC1, but not by RAD51.
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Affiliation(s)
- Wataru Kobayashi
- Laboratory of Structural Biology, Graduate School of Advanced Science &Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Motoki Takaku
- Laboratory of Structural Biology, Graduate School of Advanced Science &Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Shinichi Machida
- Laboratory of Structural Biology, Graduate School of Advanced Science &Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hiroaki Tachiwana
- Laboratory of Structural Biology, Graduate School of Advanced Science &Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Kazumitsu Maehara
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science &Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan.,Institute for Medical-oriented Structural Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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190
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The key role of CYC2 during meiosis in Tetrahymena thermophila. Protein Cell 2016; 7:236-249. [PMID: 27008457 PMCID: PMC4818844 DOI: 10.1007/s13238-016-0254-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/12/2016] [Indexed: 01/30/2023] Open
Abstract
Meiotic recombination is carried out through a specialized pathway for the formation and repair of DNA double-strand breaks (DSBs) made by the Spo11 protein. The present study shed light on the functional role of cyclin, CYC2, in Tetrahymena thermophila which has transcriptionally high expression level during meiosis process. Knocking out the CYC2 gene results in arrest of meiotic conjugation process at 2.5–3.5 h after conjugation initiation, before the meiosis division starts, and in company with the absence of DSBs. To investigate the underlying mechanism of this phenomenon, a complete transcriptome profile was performed between wild-type strain and CYC2 knock-out strain. Functional analysis of RNA-Seq results identifies related differentially expressed genes (DEGs) including SPO11 and these DEGs are enriched in DNA repair/mismatch repair (MMR) terms in homologous recombination (HR), which indicates that CYC2 could play a crucial role in meiosis by regulating SPO11 and participating in HR.
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191
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Affiliation(s)
- Corentin Claeys Bouuaert
- Howard Hughes Medical Institute, Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Scott Keeney
- Howard Hughes Medical Institute, Molecular Biology Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
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192
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Robert T, Nore A, Brun C, Maffre C, Crimi B, Bourbon HM, de Massy B. The TopoVIB-Like protein family is required for meiotic DNA double-strand break formation. Science 2016; 351:943-9. [PMID: 26917764 DOI: 10.1126/science.aad5309] [Citation(s) in RCA: 171] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Meiotic recombination is induced by the formation of DNA double-strand breaks (DSBs) catalyzed by SPO11, the ortholog of subunit A of TopoVI DNA topoisomerase (TopoVIA). TopoVI activity requires the interaction between A and B subunits. We identified a conserved family of plant and animal proteins [the TOPOVIB-Like (TOPOVIBL) family] that share strong structural similarity to the TopoVIB subunit of TopoVI DNA topoisomerase. We further characterize the meiotic recombination proteins Rec102 (Saccharomyces cerevisiae), Rec6 (Schizosaccharomyces pombe), and MEI-P22 (Drosophila melanogaster) as homologs to the transducer domain of TopoVIB. We demonstrate that the mouse TOPOVIBL protein interacts and forms a complex with SPO11 and is required for meiotic DSB formation. We conclude that meiotic DSBs are catalyzed by a complex involving SPO11 and TOPOVIBL.
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Affiliation(s)
- T Robert
- Institute of Human Genetics, UPR 1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier cedex 05, France
| | - A Nore
- Institute of Human Genetics, UPR 1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier cedex 05, France
| | - C Brun
- Institute of Human Genetics, UPR 1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier cedex 05, France
| | - C Maffre
- Institute of Human Genetics, UPR 1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier cedex 05, France
| | - B Crimi
- Institute of Human Genetics, UPR 1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier cedex 05, France
| | - H-M Bourbon
- Centre de Biologie du Développement, Université Fédérale de Toulouse, Paul Sabatier Campus, 118 Route de Narbonne, 31062 Toulouse, France.
| | - B de Massy
- Institute of Human Genetics, UPR 1142 CNRS, 141 Rue de la Cardonille, 34396 Montpellier cedex 05, France.
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193
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Leung WK, Humphryes N, Afshar N, Argunhan B, Terentyev Y, Tsubouchi T, Tsubouchi H. The synaptonemal complex is assembled by a polySUMOylation-driven feedback mechanism in yeast. J Cell Biol 2016; 211:785-93. [PMID: 26598615 PMCID: PMC4657171 DOI: 10.1083/jcb.201506103] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Synaptonemal complex (SC) assembly requires polySUMOylation of Ecm11, which promotes polymerization of Zip1, the transverse filament, whereas the N terminus of Zip1 activates Ecm11 polySUMOylation, suggesting that this positive feedback loop underpins SC assembly. During meiotic prophase I, proteinaceous structures called synaptonemal complexes (SCs) connect homologous chromosomes along their lengths via polymeric arrays of transverse filaments (TFs). Thus, control of TF polymerization is central to SC formation. Using budding yeast, we show that efficiency of TF polymerization closely correlates with the extent of SUMO conjugation to Ecm11, a component of SCs. HyperSUMOylation of Ecm11 leads to highly aggregative TFs, causing frequent assembly of extrachromosomal structures. In contrast, hypoSUMOylation leads to discontinuous, fragmented SCs, indicative of defective TF polymerization. We further show that the N terminus of the yeast TF, Zip1, serves as an activator for Ecm11 SUMOylation. Coexpression of the Zip1 N terminus and Gmc2, a binding partner of Ecm11, is sufficient to induce robust polySUMOylation of Ecm11 in nonmeiotic cells. Because TF assembly is mediated through N-terminal head-to-head associations, our results suggest that mutual activation between TF assembly and Ecm11 polySUMOylation acts as a positive feedback loop that underpins SC assembly.
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Affiliation(s)
- Wing-Kit Leung
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, England, UK
| | - Neil Humphryes
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, England, UK
| | - Negar Afshar
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, England, UK
| | - Bilge Argunhan
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, England, UK
| | - Yaroslav Terentyev
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, England, UK
| | - Tomomi Tsubouchi
- National Institute for Basic Biology, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Hideo Tsubouchi
- Genome Damage and Stability Centre, Life Sciences, University of Sussex, Brighton BN19RQ, England, UK
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194
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Mitochondrial Hsp90 is a ligand-activated molecular chaperone coupling ATP binding to dimer closure through a coiled-coil intermediate. Proc Natl Acad Sci U S A 2016; 113:2952-7. [PMID: 26929380 DOI: 10.1073/pnas.1516167113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Heat-shock protein of 90 kDa (Hsp90) is an essential molecular chaperone that adopts different 3D structures associated with distinct nucleotide states: a wide-open, V-shaped dimer in the apo state and a twisted, N-terminally closed dimer with ATP. Although the N domain is known to mediate ATP binding, how Hsp90 senses the bound nucleotide and facilitates dimer closure remains unclear. Here we present atomic structures of human mitochondrial Hsp90N (TRAP1N) and a composite model of intact TRAP1 revealing a previously unobserved coiled-coil dimer conformation that may precede dimer closure and is conserved in intact TRAP1 in solution. Our structure suggests that TRAP1 normally exists in an autoinhibited state with the ATP lid bound to the nucleotide-binding pocket. ATP binding displaces the ATP lid that signals the cis-bound ATP status to the neighboring subunit in a highly cooperative manner compatible with the coiled-coil intermediate state. We propose that TRAP1 is a ligand-activated molecular chaperone, which couples ATP binding to dramatic changes in local structure required for protein folding.
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195
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Vrielynck N, Chambon A, Vezon D, Pereira L, Chelysheva L, De Muyt A, Mezard C, Mayer C, Grelon M. A DNA topoisomerase VI-like complex initiates meiotic recombination. Science 2016; 351:939-43. [DOI: 10.1126/science.aad5196] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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196
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Ortiz-Ramírez C, Hernandez-Coronado M, Thamm A, Catarino B, Wang M, Dolan L, Feijó JA, Becker JD. A Transcriptome Atlas of Physcomitrella patens Provides Insights into the Evolution and Development of Land Plants. MOLECULAR PLANT 2016; 9:205-220. [PMID: 26687813 DOI: 10.1016/j.molp.2015.12.002] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/28/2015] [Accepted: 12/01/2015] [Indexed: 05/08/2023]
Abstract
Identifying the genetic mechanisms that underpin the evolution of new organ and tissue systems is an aim of evolutionary developmental biology. Comparative functional genetic studies between angiosperms and bryophytes can define those genetic changes that were responsible for developmental innovations. Here, we report the generation of a transcriptome atlas covering most phases in the life cycle of the model bryophyte Physcomitrella patens, including detailed sporophyte developmental progression. We identified a comprehensive set of sporophyte-specific transcription factors, and found that many of these genes have homologs in angiosperms that function in developmental processes such as flowering and shoot branching. Deletion of the PpTCP5 transcription factor results in development of supernumerary sporangia attached to a single seta, suggesting that it negatively regulates branching in the moss sporophyte. Given that TCP genes repress branching in angiosperms, we suggest that this activity is ancient. Finally, comparison of P. patens and Arabidopsis thaliana transcriptomes led us to the identification of a conserved core of transcription factors expressed in tip-growing cells. We identified modifications in the expression patterns of these genes that could account for developmental differences between P. patens tip-growing cells and A. thaliana pollen tubes and root hairs.
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Affiliation(s)
- Carlos Ortiz-Ramírez
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | | | - Anna Thamm
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal
| | - Bruno Catarino
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Mingyi Wang
- Division of Plant Biology, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - José A Feijó
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal; Department of Cell Biology and Molecular Genetics, University of Maryland, 0118 BioScience Research Building, College Park, MD 20742-5815, USA
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
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197
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Kadyrova LY, Kadyrov FA. Endonuclease activities of MutLα and its homologs in DNA mismatch repair. DNA Repair (Amst) 2016; 38:42-49. [PMID: 26719141 PMCID: PMC4820397 DOI: 10.1016/j.dnarep.2015.11.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 08/26/2015] [Accepted: 11/30/2015] [Indexed: 12/28/2022]
Abstract
MutLα is a key component of the DNA mismatch repair system in eukaryotes. The DNA mismatch repair system has several genetic stabilization functions. Of these functions, DNA mismatch repair is the major one. The loss of MutLα abolishes DNA mismatch repair, thereby predisposing humans to cancer. MutLα has an endonuclease activity that is required for DNA mismatch repair. The endonuclease activity of MutLα depends on the DQHA(X)2E(X)4E motif which is a part of the active site of the nuclease. This motif is also present in many bacterial MutL and eukaryotic MutLγ proteins, DNA mismatch repair system factors that are homologous to MutLα. Recent studies have shown that yeast MutLγ and several MutL proteins containing the DQHA(X)2E(X)4E motif possess endonuclease activities. Here, we review the endonuclease activities of MutLα and its homologs in the context of DNA mismatch repair.
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Affiliation(s)
- Lyudmila Y Kadyrova
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Farid A Kadyrov
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
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198
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Bloomfield G. Atypical ploidy cycles, Spo11, and the evolution of meiosis. Semin Cell Dev Biol 2016; 54:158-64. [PMID: 26811992 DOI: 10.1016/j.semcdb.2016.01.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 01/20/2016] [Indexed: 12/14/2022]
Abstract
The Spo11 protein induces DNA double strand breaks before the first division of meiosis, enabling the formation of the chiasmata that physically link homologous chromosomes as they align. Spo11 is an ancient and well conserved protein, related in sequence and structure to a DNA topoisomerase subunit found in Archaea as well as a subset of eukaryotes. However the origins of its meiotic function are unclear. This review examines some apparent exceptions to the rule that Spo11 activity is specific to, and required for meiosis. Spo11 appears to function in the context of unusual forms of ploidy reduction in some protists and fungi. One lineage of amoebae, the dictyostelids, is thought to undergo meiosis during its sexual cycle despite having lost Spo11 entirely. Further experimental characterisation of these and other non-canonical ploidy cycling mechanisms may cast light of the evolution of meiosis.
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Affiliation(s)
- Gareth Bloomfield
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom.
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199
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Lake CM, Hawley RS. Becoming a crossover-competent DSB. Semin Cell Dev Biol 2016; 54:117-25. [PMID: 26806636 DOI: 10.1016/j.semcdb.2016.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/06/2016] [Indexed: 12/16/2022]
Abstract
The proper execution of meiotic recombination (or crossing over) is essential for chromosome segregation during the first meiotic division, and thus this process is regulated by multiple, and often elaborate, mechanisms. Meiotic recombination begins with the programmed induction of DNA double-strand breaks (DSBs), of which only a subset are selected to be repaired into crossovers. This crossover selection process is carried out by a number of pro-crossover proteins that regulate the fashion in which DSBs are repaired. Here, we highlight recent studies regarding the process of DSB fate selection by a family of pro-crossover proteins known as the Zip-3 homologs.
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Affiliation(s)
- Cathleen M Lake
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - R Scott Hawley
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; Department of Molecular and Integrative Physiology, Kansas University Medical Center, Kansas City, KS 66160, USA.
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200
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Radicicol-Mediated Inhibition of Topoisomerase VIB-VIA Activity of the Human Malaria Parasite Plasmodium falciparum. mSphere 2016; 1:mSphere00025-15. [PMID: 27303712 PMCID: PMC4863635 DOI: 10.1128/msphere.00025-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/06/2015] [Indexed: 11/20/2022] Open
Abstract
In this study we characterize topoisomerase VI from Plasmodium falciparum using genetic and biochemical approaches. We use various inhibitors and identify radicicol as a specific inhibitor of its decatenation activity. We establish a very simple and economical biochemical assay system that can be exploited to screen inhibitors of PfTopoVI. Plasmodium falciparum topoisomerase VIB (TopoVIB)-TopoVIA (TopoVIB-VIA) complex can be potentially exploited as a drug target against malaria due to its absence from the human genome. Previous work in our laboratory has suggested that P. falciparum TopoVIB (PfTopoVIB) might be a target of radicicol since treatment of parasite cultures with this antibiotic is associated with upregulation of Plasmodium TopoVIB at the transcript level as well as at the protein level. Further studies demonstrated that radicicol treatment impaired mitochondrial replication of human malaria parasite P. falciparum. However, the technical challenge associated with the expression of the above protein complex hampered its functional characterization. Using Saccharomyces cerevisiae as a heterologous system, we expressed PfTopoVIB (Myc-tagged) and PfTopoVIA (Flag-tagged) (PfTopoVIB-VIA) proteins. Yeast two-hybrid analysis showed the formation of PfTopoVIB homodimers and PfTopoVIB/PfTopoVIA heteromers. Our study demonstrated that PfTopoVIB and PfTopoVIA together can rescue the lethal phenotype of yeast ΔtopoII mutants, whereas Plasmodium topoisomerase VIB alone cannot. Using yeast cell-free extracts harboring the PfTopoVIB-VIA protein complex, we have performed a decatenation assay and observed that PfTopoVIB-VIA can decatenate DNA in an ATP- and Mg2+-dependent manner. The specificity of this enzyme is established by abrogation of its activity in the presence of PfTopoVIB-specific antibody. Our study results show that radicicol and etoposide can specifically inhibit PfTopoVIB-VIA decatenation activity whereas the gyrase inhibitor novobiocin cannot. Such a yeast-based assay system can be employed in screening specific inhibitors against Plasmodium VIB-VIA. IMPORTANCE In this study we characterize topoisomerase VI from Plasmodium falciparum using genetic and biochemical approaches. We use various inhibitors and identify radicicol as a specific inhibitor of its decatenation activity. We establish a very simple and economical biochemical assay system that can be exploited to screen inhibitors of PfTopoVI.
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