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CRISPR Technology Reveals RAD(51)-ical Mechanisms of Repair in Roundworms: An Educational Primer for Use with "Promotion of Homologous Recombination by SWS-1 in Complex with RAD-51 Paralogs in Caenorhabditis elegans". Genetics 2017; 204:883-891. [PMID: 28114101 DOI: 10.1534/genetics.116.195479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The mechanisms cells use to maintain genetic fidelity via DNA repair and the accuracy of these processes have garnered interest from scientists engaged in basic research to clinicians seeking improved treatment for cancer patients. Despite the continued advances, many details of DNA repair are still incompletely understood. In addition, the inherent complexity of DNA repair processes, even at the most fundamental level, makes it a challenging topic. This primer is meant to assist both educators and students in using a recent paper, "Promotion of homologous recombination by SWS-1 in complex with RAD-51 paralogs in Caenorhabditis elegans," to understand mechanisms of DNA repair. The goals of this primer are to highlight and clarify several key techniques utilized, with special emphasis on the clustered, regularly interspaced, short palindromic repeats technique and the ways in which it has revolutionized genetics research, as well as to provide questions for deeper in-class discussion.
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152
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Shodhan A, Kataoka K, Mochizuki K, Novatchkova M, Loidl J. A Zip3-like protein plays a role in crossover formation in the SC-less meiosis of the protist Tetrahymena. Mol Biol Cell 2017; 28:825-833. [PMID: 28100637 PMCID: PMC5349789 DOI: 10.1091/mbc.e16-09-0678] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/21/2016] [Accepted: 01/09/2017] [Indexed: 11/11/2022] Open
Abstract
When programmed meiotic DNA double-strand breaks (DSBs) undergo recombinational repair, genetic crossovers (COs) may be formed. A certain level of this is required for the faithful segregation of chromosomes, but the majority of DSBs are processed toward a safer alternative, namely noncrossovers (NCOs), via nonreciprocal DNA exchange. At the crossroads between these two DSB fates is the Msh4-Msh5 (MutSγ) complex, which stabilizes CO-destined recombination intermediates and members of the Zip3/RNF212 family of RING finger proteins, which in turn stabilize MutSγ. These proteins function in the context of the synaptonemal complex (SC) and mainly act on SC-dependent COs. Here we show that in the SC-less ciliate Tetrahymena, Zhp3 (a protein distantly related to Zip3/RNF212), together with MutSγ, is responsible for the majority of COs. This activity of Zhp3 suggests an evolutionarily conserved SC-independent strategy for balancing CO:NCO ratios. Moreover, we report a novel meiosis-specific protein, Sa15, as an interacting partner of Zhp3. Sa15 forms linear structures in meiotic prophase nuclei to which Zhp3 localizes. Sa15 is required for a wild-type level of CO formation. Its linear organization suggests the existence of an underlying chromosomal axis that serves as a scaffold for Zhp3 and other recombination proteins.
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Affiliation(s)
- Anura Shodhan
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Kensuke Kataoka
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
| | - Kazufumi Mochizuki
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
| | - Maria Novatchkova
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences and
- Research Institute of Molecular Pathology, 1030 Vienna, Austria
| | - Josef Loidl
- Department of Chromosome Biology, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
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153
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Syrjänen JL, Heller I, Candelli A, Davies OR, Peterman EJG, Wuite GJL, Pellegrini L. Single-molecule observation of DNA compaction by meiotic protein SYCP3. eLife 2017; 6. [PMID: 28287952 PMCID: PMC5348128 DOI: 10.7554/elife.22582] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 03/04/2017] [Indexed: 12/14/2022] Open
Abstract
In a previous paper (Syrjänen et al., 2014), we reported the first structural characterisation of a synaptonemal complex (SC) protein, SYCP3, which led us to propose a model for its role in chromosome compaction during meiosis. As a component of the SC lateral element, SYCP3 has a critical role in defining the specific chromosome architecture required for correct meiotic progression. In the model, the reported compaction of chromosomal DNA caused by SYCP3 would result from its ability to bridge distant sites on a DNA molecule with the DNA-binding domains located at each end of its strut-like structure. Here, we describe a single-molecule assay based on optical tweezers, fluorescence microscopy and microfluidics that, in combination with bulk biochemical data, provides direct visual evidence for our proposed mechanism of SYCP3-mediated chromosome organisation. DOI:http://dx.doi.org/10.7554/eLife.22582.001
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Affiliation(s)
- Johanna L Syrjänen
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Iddo Heller
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Andrea Candelli
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Owen R Davies
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, United Kingdom
| | - Erwin J G Peterman
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Gijs J L Wuite
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,LaserLaB, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Luca Pellegrini
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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154
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Proteasomes on the chromosome. Cell Res 2017; 27:602-603. [PMID: 28266542 DOI: 10.1038/cr.2017.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Targeted proteolysis plays an important role in the execution and regulation of many cellular events. Two recent papers in Science identify novel roles for proteasome-mediated proteolysis in homologous chromosome pairing, recombination, and segregation during meiosis.
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155
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Pelisch F, Tammsalu T, Wang B, Jaffray EG, Gartner A, Hay RT. A SUMO-Dependent Protein Network Regulates Chromosome Congression during Oocyte Meiosis. Mol Cell 2017; 65:66-77. [PMID: 27939944 PMCID: PMC5222697 DOI: 10.1016/j.molcel.2016.11.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/29/2016] [Accepted: 10/31/2016] [Indexed: 01/20/2023]
Abstract
During Caenorhabditis elegans oocyte meiosis, a multi-protein ring complex (RC) localized between homologous chromosomes, promotes chromosome congression through the action of the chromokinesin KLP-19. While some RC components are known, the mechanism of RC assembly has remained obscure. We show that SUMO E3 ligase GEI-17/PIAS is required for KLP-19 recruitment to the RC, and proteomic analysis identified KLP-19 as a SUMO substrate in vivo. In vitro analysis revealed that KLP-19 is efficiently sumoylated in a GEI-17-dependent manner, while GEI-17 undergoes extensive auto-sumoylation. GEI-17 and another RC component, the kinase BUB-1, contain functional SUMO interaction motifs (SIMs), allowing them to recruit SUMO modified proteins, including KLP-19, into the RC. Thus, dynamic SUMO modification and the presence of SIMs in RC components generate a SUMO-SIM network that facilitates assembly of the RC. Our results highlight the importance of SUMO-SIM networks in regulating the assembly of dynamic protein complexes.
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Affiliation(s)
- Federico Pelisch
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Triin Tammsalu
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Bin Wang
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Ellis G Jaffray
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Anton Gartner
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Ronald T Hay
- Centre for Gene Regulation and Expression, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
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156
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157
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Gao J, Barroso C, Zhang P, Kim HM, Li S, Labrador L, Lightfoot J, Gerashchenko MV, Labunskyy VM, Dong MQ, Martinez-Perez E, Colaiácovo MP. N-terminal acetylation promotes synaptonemal complex assembly in C. elegans. Genes Dev 2016; 30:2404-2416. [PMID: 27881602 PMCID: PMC5131780 DOI: 10.1101/gad.277350.116] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 10/20/2016] [Indexed: 12/16/2022]
Abstract
N-terminal acetylation of the first two amino acids on proteins is a prevalent cotranslational modification. Despite its abundance, the biological processes associated with this modification are not well understood. Here, we mapped the pattern of protein N-terminal acetylation in Caenorhabditis elegans, uncovering a conserved set of rules for this protein modification and identifying substrates for the N-terminal acetyltransferase B (NatB) complex. We observed an enrichment for global protein N-terminal acetylation and also specifically for NatB substrates in the nucleus, supporting the importance of this modification for regulating biological functions within this cellular compartment. Peptide profiling analysis provides evidence of cross-talk between N-terminal acetylation and internal modifications in a NAT substrate-specific manner. In vivo studies indicate that N-terminal acetylation is critical for meiosis, as it regulates the assembly of the synaptonemal complex (SC), a proteinaceous structure ubiquitously present during meiosis from yeast to humans. Specifically, N-terminal acetylation of NatB substrate SYP-1, an SC structural component, is critical for SC assembly. These findings provide novel insights into the biological functions of N-terminal acetylation and its essential role during meiosis.
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Affiliation(s)
- Jinmin Gao
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Consuelo Barroso
- Medical Research Council Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - Pan Zhang
- College of Life Science, Beijing Normal University, Beijing 100875, China; National Institute of Biological Sciences, Beijing 102206, China
| | - Hyun-Min Kim
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Shangtong Li
- College of Life Science, Beijing Normal University, Beijing 100875, China; National Institute of Biological Sciences, Beijing 102206, China
| | - Leticia Labrador
- Medical Research Council Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - James Lightfoot
- Medical Research Council Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - Maxim V. Gerashchenko
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Vyacheslav M. Labunskyy
- Department of Dermatology, Boston University School of Medicine, Boston, Massachusetts 02218, USA
| | - Meng-Qiu Dong
- College of Life Science, Beijing Normal University, Beijing 100875, China; National Institute of Biological Sciences, Beijing 102206, China
| | - Enrique Martinez-Perez
- Medical Research Council Clinical Sciences Centre, Imperial College London, London W12 0NN, United Kingdom
| | - Monica P. Colaiácovo
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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158
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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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159
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Abstract
Multiple meiosis-specific cohesion proteins act to facilitate homolog segregation at the first meiotic division. A recent paper demonstrates that meiotic cohesins can be separated into two complexes, one that establishes and maintains intersister cohesion and one that promotes interhomolog adhesion by regulating synaptonemal complex assembly.
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Affiliation(s)
- Cori K Cahoon
- 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, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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160
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Ayarza E, González M, López F, Fernández-Donoso R, Page J, Berrios S. Alterations in chromosomal synapses and DNA repair in apoptotic spermatocytes of Mus m. domesticus. Eur J Histochem 2016; 60:2677. [PMID: 27349323 PMCID: PMC4933834 DOI: 10.4081/ejh.2016.2677] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 05/29/2016] [Accepted: 06/01/2016] [Indexed: 11/23/2022] Open
Abstract
We investigated whether apoptotic spermatocytes from the mouse Mus m. domesticus presented alterations in chromosomal synapses and DNA repair. To enrich for apoptotic spermatocytes, the scrotum's temperature was raised by partially exposing animals for 15 min to a 42ºC water bath. Spermatocytes in initial apoptosis were identified in situ by detecting activated Caspase-9. SYCP1 and SYCP3 were markers for evaluating synapses or the structure of synaptonemal complexes and Rad51 and γH2AX for detecting DNA repair and chromatin remodeling. Apoptotic spermatocytes were concentrated in spermatogenic cycle stages III-IV (50.3%), XI-XII (44.1%) and IX-X (4.2%). Among apoptotic spermatocytes, 48% were in middle pachytene, 44% in metaphase and 6% in diplotene. Moreover, apoptotic spermatocytes showed several structural anomalies in autosomal bivalents, including splitting of chromosomal axes and partial asynapses between homologous chromosomes. gH2AX and Rad51 were atypically distributed during pachytene and as late as diplotene and associated with asynaptic chromatin, single chromosome axes or discontinuous chromosome axes. Among apoptotic spermatocytes at pachytene, 70% showed changes in the structure of synapses, 67% showed changes in gH2AX and Rad51 distribution and 50% shared alterations in both synapses and DNA repair. Our results showed that apoptotic spermatocytes from Mus m. domesticus contain a high frequency of alterations in chromosomal synapses and in the recruitment and distribution of DNA repair proteins. Together, these observations suggest that these alterations may have been detected by meiotic checkpoints triggering apoptosis.
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