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Zhang R, Liu B, Tian Y, Xin M, Li Q, Huang X, Liu Y, Zhao L, Qi F, Wang R, Meng X, Chen J, Zhou J, Gao J. A chromosome-coupled ubiquitin-proteasome pathway is required for meiotic surveillance. Cell Death Differ 2024:10.1038/s41418-024-01375-6. [PMID: 39237708 DOI: 10.1038/s41418-024-01375-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 08/29/2024] [Accepted: 09/02/2024] [Indexed: 09/07/2024] Open
Abstract
Defects in meiotic prophase can cause meiotic chromosome missegregation and aneuploid gamete formation. Meiotic checkpoints are activated in germ cells with meiotic defects, and cells with unfixed errors are eliminated by apoptosis. How such a surveillance process is regulated remains elusive. Here, we report that a chromosome-coupled ubiquitin-proteasome pathway (UPP) regulates meiotic checkpoint activation and promotes germ cell apoptosis in C. elegans meiosis-defective mutants. We identified an F-box protein, FBXL-2, that functions as a core component within the pathway. This chromosome-coupled UPP regulates meiotic DSB repair kinetics and chromosome dynamic behaviors in synapsis defective mutants. Disrupted UPP impairs the axial recruitment of the HORMA domain protein HIM-3, which is required for efficient germ cell apoptosis in synapsis defective mutants. Our data suggest that an efficient chromosome-coupled UPP functions as a part of the meiotic surveillance system by enhancing the integrity of the meiotic chromosome axis.
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Affiliation(s)
- Ruirui Zhang
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Bohan Liu
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Yuqi Tian
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Mingyu Xin
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Qian Li
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xiuhua Huang
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Yuanyuan Liu
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Li Zhao
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Feifei Qi
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Ruoxi Wang
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Xiaoqian Meng
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
| | - Jianguo Chen
- Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
- Center for Quantitative Biology, Peking University, Beijing, 100871, China
| | - Jun Zhou
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jinmin Gao
- Center for Cell Structure and Function, College of Life Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Shandong Normal University, Jinan, 250358, China.
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, 300071, China.
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2
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Li Q, Hariri S, Calidas A, Kaur A, Huey E, Engebrecht J. The chromatin-associated 53BP1 ortholog, HSR-9, regulates recombinational repair and X chromosome segregation in the Caenorhabditis elegans germ line. Genetics 2024; 227:iyae102. [PMID: 38884610 DOI: 10.1093/genetics/iyae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/29/2024] [Accepted: 06/03/2024] [Indexed: 06/18/2024] Open
Abstract
53BP1 plays a crucial role in regulating DNA damage repair pathway choice and checkpoint signaling in somatic cells; however, its role in meiosis has remained enigmatic. In this study, we demonstrate that the Caenorhabditis elegans ortholog of 53BP1, HSR-9, associates with chromatin in both proliferating and meiotic germ cells. Notably, HSR-9 is enriched on the X chromosome pair in pachytene oogenic germ cells. HSR-9 is also present at kinetochores during both mitotic and meiotic divisions but does not appear to be essential for monitoring microtubule-kinetochore attachments or tension. Using cytological markers of different steps in recombinational repair, we found that HSR-9 influences the processing of a subset of meiotic double-stranded breaks into COSA-1-marked crossovers. Additionally, HSR-9 plays a role in meiotic X chromosome segregation under conditions where X chromosomes fail to pair, synapse, and recombine. Together, these results highlight that chromatin-associated HSR-9 has both conserved and unique functions in the regulation of meiotic chromosome behavior.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, CA 95616, USA
| | - Sara Hariri
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, CA 95616, USA
| | - Aashna Calidas
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
| | - Arshdeep Kaur
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
| | - Erica Huey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, CA 95616, USA
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3
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Arter M, Keeney S. Divergence and conservation of the meiotic recombination machinery. Nat Rev Genet 2024; 25:309-325. [PMID: 38036793 DOI: 10.1038/s41576-023-00669-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 12/02/2023]
Abstract
Sexually reproducing eukaryotes use recombination between homologous chromosomes to promote chromosome segregation during meiosis. Meiotic recombination is almost universally conserved in its broad strokes, but specific molecular details often differ considerably between taxa, and the proteins that constitute the recombination machinery show substantial sequence variability. The extent of this variation is becoming increasingly clear because of recent increases in genomic resources and advances in protein structure prediction. We discuss the tension between functional conservation and rapid evolutionary change with a focus on the proteins that are required for the formation and repair of meiotic DNA double-strand breaks. We highlight phylogenetic relationships on different time scales and propose that this remarkable evolutionary plasticity is a fundamental property of meiotic recombination that shapes our understanding of molecular mechanisms in reproductive biology.
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Affiliation(s)
- Meret Arter
- Molecular Biology Program, 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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4
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Li Q, Hariri S, Calidas A, Kaur A, Huey E, Engebrecht J. The chromatin-associated 53BP1 ortholog, HSR-9, regulates recombinational repair and X chromosome segregation in the Caenorhabditis elegans germ line. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589267. [PMID: 38659880 PMCID: PMC11042201 DOI: 10.1101/2024.04.12.589267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
53BP1 plays a crucial role in regulating DNA damage repair pathway choice and checkpoint signaling in somatic cells; however, its role in meiosis has remained enigmatic. In this study, we demonstrate that the Caenorhabditis elegans ortholog of 53BP1, HSR-9, associates with chromatin in both proliferating and meiotic germ cells. Notably, HSR-9 is enriched on the X chromosome pair in pachytene oogenic germ cells. HSR-9 is also present at kinetochores during both mitotic and meiotic divisions but does not appear to be essential for monitoring microtubule-kinetochore attachments or tension. Using cytological markers of different steps in recombinational repair, we found that HSR-9 influences the processing of a subset of meiotic double strand breaks into COSA-1-marked crossovers. Additionally, HSR-9 plays a role in meiotic X chromosome segregation under conditions where X chromosomes fail to pair, synapse, and recombine. Together, these results highlight that chromatin-associated HSR-9 has both conserved and unique functions in the regulation of meiotic chromosome behavior.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California 95616
| | - Sara Hariri
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California 95616
| | - Aashna Calidas
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Arshdeep Kaur
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - Erica Huey
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California 95616
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California 95616
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5
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Beaudier P, Devès G, Plawinski L, Dupuy D, Barberet P, Seznec H. Proton Microbeam Targeted Irradiation of the Gonad Primordium Region Induces Developmental Alterations Associated with Heat Shock Responses and Cuticle Defense in Caenorhabditis elegans. BIOLOGY 2023; 12:1372. [PMID: 37997971 PMCID: PMC10669138 DOI: 10.3390/biology12111372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 11/25/2023]
Abstract
We describe a methodology to manipulate Caenorhabditis elegans (C. elegans) and irradiate the stem progenitor gonad region using three MeV protons at a specific developmental stage (L1). The consequences of the targeted irradiation were first investigated by considering the organogenesis of the vulva and gonad, two well-defined and characterized developmental systems in C. elegans. In addition, we adapted high-throughput analysis protocols, using cell-sorting assays (COPAS) and whole transcriptome analysis, to the limited number of worms (>300) imposed by the selective irradiation approach. Here, the presented status report validated protocols to (i) deliver a controlled dose in specific regions of the worms; (ii) immobilize synchronized worm populations (>300); (iii) specifically target dedicated cells; (iv) study the radiation-induced developmental alterations and gene induction involved in cellular stress (heat shock protein) and cuticle injury responses that were found.
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Affiliation(s)
- Pierre Beaudier
- University Bordeaux, CNRS, LP2I, UMR 5797, 33170 Gradignan, France; (P.B.); (G.D.); (L.P.); (P.B.)
| | - Guillaume Devès
- University Bordeaux, CNRS, LP2I, UMR 5797, 33170 Gradignan, France; (P.B.); (G.D.); (L.P.); (P.B.)
| | - Laurent Plawinski
- University Bordeaux, CNRS, LP2I, UMR 5797, 33170 Gradignan, France; (P.B.); (G.D.); (L.P.); (P.B.)
| | - Denis Dupuy
- University Bordeaux, INSERM, U1212, 33607 Pessac, France
| | - Philippe Barberet
- University Bordeaux, CNRS, LP2I, UMR 5797, 33170 Gradignan, France; (P.B.); (G.D.); (L.P.); (P.B.)
| | - Hervé Seznec
- University Bordeaux, CNRS, LP2I, UMR 5797, 33170 Gradignan, France; (P.B.); (G.D.); (L.P.); (P.B.)
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6
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Liu C, Rex R, Lung Z, Wang JS, Wu F, Kim HJ, Zhang L, Sohn LL, Dernburg AF. A cooperative network at the nuclear envelope counteracts LINC-mediated forces during oogenesis in C. elegans. SCIENCE ADVANCES 2023; 9:eabn5709. [PMID: 37436986 PMCID: PMC10337908 DOI: 10.1126/sciadv.abn5709] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 06/08/2023] [Indexed: 07/14/2023]
Abstract
Oogenesis involves transduction of mechanical forces from the cytoskeleton to the nuclear envelope (NE). In Caenorhabditis elegans, oocyte nuclei lacking the single lamin protein LMN-1 are vulnerable to collapse under forces mediated through LINC (linker of nucleoskeleton and cytoskeleton) complexes. Here, we use cytological analysis and in vivo imaging to investigate the balance of forces that drive this collapse and protect oocyte nuclei. We also use a mechano-node-pore sensing device to directly measure the effect of genetic mutations on oocyte nuclear stiffness. We find that nuclear collapse is not a consequence of apoptosis. It is promoted by dynein, which induces polarization of a LINC complex composed of Sad1 and UNC-84 homology 1 (SUN-1) and ZYGote defective 12 (ZYG-12). Lamins contribute to oocyte nuclear stiffness and cooperate with other inner nuclear membrane proteins to distribute LINC complexes and protect nuclei from collapse. We speculate that a similar network may protect oocyte integrity during extended oocyte arrest in mammals.
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Affiliation(s)
- Chenshu Liu
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Rachel Rex
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Zoe Lung
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - John S. Wang
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Fan Wu
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Hyung Jun Kim
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Liangyu Zhang
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Lydia L. Sohn
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Abby F. Dernburg
- California Institute for Quantitative Biosciences (QB3) and Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
- Department of Biological Sciences and Engineering, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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7
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Li Q, Kaur A, Okada K, McKenney RJ, Engebrecht J. Differential requirement for BRCA1-BARD1 E3 ubiquitin ligase activity in DNA damage repair and meiosis in the Caenorhabditis elegans germ line. PLoS Genet 2023; 19:e1010457. [PMID: 36716349 PMCID: PMC9910797 DOI: 10.1371/journal.pgen.1010457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/09/2023] [Accepted: 01/19/2023] [Indexed: 02/01/2023] Open
Abstract
The tumor suppressor BRCA1-BARD1 complex regulates many cellular processes; of critical importance to its tumor suppressor function is its role in genome integrity. Although RING E3 ubiquitin ligase activity is the only known enzymatic activity of the complex, the in vivo requirement for BRCA1-BARD1 E3 ubiquitin ligase activity has been controversial. Here we probe the role of BRCA1-BARD1 E3 ubiquitin ligase activity in vivo using C. elegans. Genetic, cell biological, and biochemical analyses of mutants defective for E3 ligase activity suggest there is both E3 ligase-dependent and independent functions of the complex in the context of DNA damage repair and meiosis. We show that E3 ligase activity is important for nuclear accumulation of the complex and specifically to concentrate at meiotic recombination sites but not at DNA damage sites in proliferating germ cells. While BRCA1 alone is capable of monoubiquitylation, BARD1 is required with BRCA1 to promote polyubiquitylation. We find that the requirement for E3 ligase activity and BARD1 in DNA damage signaling and repair can be partially alleviated by driving the nuclear accumulation and self-association of BRCA1. Our data suggest that in addition to E3 ligase activity, BRCA1 may serve a structural role for DNA damage signaling and repair while BARD1 plays an accessory role to enhance BRCA1 function.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California, United States of America
| | - Arshdeep Kaur
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Kyoko Okada
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
| | - Richard J. McKenney
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California, United States of America
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, California, United States of America
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California Davis, Davis, California, United States of America
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8
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Li Q, Kaur A, Mallory B, Hariri S, Engebrecht J. Inducible degradation of dosage compensation protein DPY-27 facilitates isolation of Caenorhabditis elegans males for molecular and biochemical analyses. G3 (BETHESDA, MD.) 2022; 12:jkac085. [PMID: 35404452 PMCID: PMC9073673 DOI: 10.1093/g3journal/jkac085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/04/2022] [Indexed: 04/22/2023]
Abstract
Biological sex affects numerous aspects of biology, yet how sex influences different biological processes have not been extensively studied at the molecular level. Caenorhabditis elegans, with both hermaphrodites (functionally females as adults) and males, is an excellent system to uncover how sex influences physiology. Here, we describe a method to isolate large quantities of C. elegans males by conditionally degrading DPY-27, a component of the dosage compensation complex essential for hermaphrodite, but not male, development. We show that germ cells from males isolated following DPY-27 degradation undergo meiosis and spermiogenesis like wild type and these males are competent to mate and sire viable offspring. We further demonstrate the efficacy of this system by analyzing gene expression and performing affinity pull-downs from male worm extracts.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA
| | - Arshdeep Kaur
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Benjamin Mallory
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
| | - Sara Hariri
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA
- Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA
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9
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Germoglio M, Adamo A, Incerti G, Cartenì F, Gigliotti S, Storlazzi A, Mazzoleni S. Self-DNA Exposure Induces Developmental Defects and Germline DNA Damage Response in Caenorhabditis elegans. BIOLOGY 2022; 11:262. [PMID: 35205128 PMCID: PMC8869574 DOI: 10.3390/biology11020262] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 02/06/2023]
Abstract
All organisms, from bacteria to mammals, sense and respond to foreign nucleic acids to fight infections in order to survive and preserve genome integrity across generations. The innate immune system is an evolutionarily conserved defence strategy. Complex organisms have developed various cellular processes to respond to and recognise not only infections, i.e., pathogen-associated molecular patterns (PAMPs), but also to sense injury and tissue dysfunctions, i.e., damage-associated molecular patterns (DAMPs). Mis-localized self-DNA can be sensed as DAMP by specific DNA-sensing pathways, and self-DNA chronic exposure can be detrimental to the organisms. Here, we investigate the effects of dietary delivered self-DNA in the nematode Caenorhabditis elegans. The hermaphrodite worms were fed on Escherichia coli genomic libraries: a C. elegans library (self) and a legume (Medicago truncatula) library (non-self). We show that the self-library diet affects embryogenesis, larval development and gametogenesis. DNA damage and activation of p53/CEP-1-dependent apoptosis occur in gonadal germ cells. Studies of self-DNA exposure in this model organism were not pursued up to now. The genetic tractability of C. elegans will help to identify the basic molecular pathways involved in such mechanisms. The specificity of the adverse effects associated with a self-DNA enriched diet suggests applications in biological pest control approaches.
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Affiliation(s)
- Marcello Germoglio
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Adele Adamo
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Guido Incerti
- Department of Agri-Food, Animal and Environmental Sciences (DI4A), University of Udine, 33100 Udine, Italy;
| | - Fabrizio Cartenì
- Department of Agricultural Sciences, Università degli Studi di Napoli Federico II, 80055 Portici, Italy;
| | - Silvia Gigliotti
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Aurora Storlazzi
- Institute of Biosciences and BioResources, National Research Council, Via Pietro Castellino 111, 80131 Napoli, Italy; (M.G.); (A.A.); (S.G.)
| | - Stefano Mazzoleni
- Department of Agricultural Sciences, Università degli Studi di Napoli Federico II, 80055 Portici, Italy;
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10
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Silva N, Castellano-Pozo M, Matsuzaki K, Barroso C, Roman-Trufero M, Craig H, Brooks DR, Isaac RE, Boulton SJ, Martinez-Perez E. Proline-specific aminopeptidase P prevents replication-associated genome instability. PLoS Genet 2022; 18:e1010025. [PMID: 35081133 PMCID: PMC8820600 DOI: 10.1371/journal.pgen.1010025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 02/07/2022] [Accepted: 01/10/2022] [Indexed: 11/19/2022] Open
Abstract
Genotoxic stress during DNA replication constitutes a serious threat to genome integrity and causes human diseases. Defects at different steps of DNA metabolism are known to induce replication stress, but the contribution of other aspects of cellular metabolism is less understood. We show that aminopeptidase P (APP1), a metalloprotease involved in the catabolism of peptides containing proline residues near their N-terminus, prevents replication-associated genome instability. Functional analysis of C. elegans mutants lacking APP-1 demonstrates that germ cells display replication defects including reduced proliferation, cell cycle arrest, and accumulation of mitotic DSBs. Despite these defects, app-1 mutants are competent in repairing DSBs induced by gamma irradiation, as well as SPO-11-dependent DSBs that initiate meiotic recombination. Moreover, in the absence of SPO-11, spontaneous DSBs arising in app-1 mutants are repaired as inter-homologue crossover events during meiosis, confirming that APP-1 is not required for homologous recombination. Thus, APP-1 prevents replication stress without having an apparent role in DSB repair. Depletion of APP1 (XPNPEP1) also causes DSB accumulation in mitotically-proliferating human cells, suggesting that APP1’s role in genome stability is evolutionarily conserved. Our findings uncover an unexpected role for APP1 in genome stability, suggesting functional connections between aminopeptidase-mediated protein catabolism and DNA replication. The accurate duplication of DNA that occurs before cells divide is an essential aspect of the cell cycle that is also crucial for the correct development of multicellular organisms. Mutations that compromise the normal function of the DNA replication machinery can lead to the accumulation of replication-related DNA damage, a known cause of human disease and a common feature of cancer and precancerous cells. Therefore, identifying factors that prevent replication-related DNA damage is highly relevant for human health. In this manuscript, we identify aminopeptidase P, an enzyme involved in the breakdown of proteins containing the amino acid Proline at their N-terminus, as a novel factor that prevents replication-related DNA damage. Analysis of C. elegans nematodes lacking aminopeptidase P reveals that this protein is required for normal fertility and development, and that in its absence proliferating germ cells display DNA replication defects, including cell cycle arrest and accumulation of extensive DNA damage. We also show that removal of aminopeptidase P induces DNA damage in proliferating human cells, suggesting that its role in preventing replication defects is evolutionarily conserved. These findings uncover functional connections between aminopeptidase-mediated protein degradation and DNA replication.
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Affiliation(s)
- Nicola Silva
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | | | | | - Consuelo Barroso
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
| | - Monica Roman-Trufero
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
| | - Hannah Craig
- School of Biology, University of Leeds, Leeds, United Kingdom
| | - Darren R. Brooks
- School of Science, Engineering and Environment, University of Salford, Salford, United Kingdom
| | - R. Elwyn Isaac
- School of Biology, University of Leeds, Leeds, United Kingdom
| | | | - Enrique Martinez-Perez
- Medical Research Council London Institute of Medical Sciences, London, United Kingdom
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, United Kingdom
- * E-mail:
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11
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Rillo-Bohn R, Adilardi R, Mitros T, Avşaroğlu B, Stevens L, Köhler S, Bayes J, Wang C, Lin S, Baskevitch KA, Rokhsar DS, Dernburg AF. Analysis of meiosis in Pristionchus pacificus reveals plasticity in homolog pairing and synapsis in the nematode lineage. eLife 2021; 10:70990. [PMID: 34427184 PMCID: PMC8455136 DOI: 10.7554/elife.70990] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022] Open
Abstract
Meiosis is conserved across eukaryotes yet varies in the details of its execution. Here we describe a new comparative model system for molecular analysis of meiosis, the nematode Pristionchus pacificus, a distant relative of the widely studied model organism Caenorhabditis elegans. P. pacificus shares many anatomical and other features that facilitate analysis of meiosis in C. elegans. However, while C. elegans has lost the meiosis-specific recombinase Dmc1 and evolved a recombination-independent mechanism to synapse its chromosomes, P. pacificus expresses both DMC-1 and RAD-51. We find that SPO-11 and DMC-1 are required for stable homolog pairing, synapsis, and crossover formation, while RAD-51 is dispensable for these key meiotic processes. RAD-51 and DMC-1 localize sequentially to chromosomes during meiotic prophase and show nonoverlapping functions. We also present a new genetic map for P. pacificus that reveals a crossover landscape very similar to that of C. elegans, despite marked divergence in the regulation of synapsis and crossing-over between these lineages.
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Affiliation(s)
- Regina Rillo-Bohn
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Renzo Adilardi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Therese Mitros
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Barış Avşaroğlu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Lewis Stevens
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Darwin Tree of Life Project, Wellcome Sanger Institute, Cambridge, United Kingdom
| | - Simone Köhler
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Joshua Bayes
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Clara Wang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Sabrina Lin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - K Alienor Baskevitch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States
| | - Daniel S Rokhsar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Department of Energy Joint Genome Institute, Berkeley, United States.,Okinawa Institute of Science and Technology Graduate University, Onna, Japan.,Chan Zuckerberg Biohub, San Francisco, United States
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Howard Hughes Medical Institute, Chevy Chase, United States.,Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, United States.,California Institute for Quantitative Biosciences, Berkeley, United States
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12
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Rappaport Y, Achache H, Falk R, Murik O, Ram O, Tzur YB. Bisection of the X chromosome disrupts the initiation of chromosome silencing during meiosis in Caenorhabditis elegans. Nat Commun 2021; 12:4802. [PMID: 34376665 PMCID: PMC8355143 DOI: 10.1038/s41467-021-24815-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/01/2021] [Indexed: 01/04/2023] Open
Abstract
During meiosis, gene expression is silenced in aberrantly unsynapsed chromatin and in heterogametic sex chromosomes. Initiation of sex chromosome silencing is disrupted in meiocytes with sex chromosome-autosome translocations. To determine whether this is due to aberrant synapsis or loss of continuity of sex chromosomes, we engineered Caenorhabditis elegans nematodes with non-translocated, bisected X chromosomes. In early meiocytes of mutant males and hermaphrodites, X segments are enriched with euchromatin assembly markers and active RNA polymerase II staining, indicating active transcription. Analysis of RNA-seq data showed that genes from the X chromosome are upregulated in gonads of mutant worms. Contrary to previous models, which predicted that any unsynapsed chromatin is silenced during meiosis, our data indicate that unsynapsed X segments are transcribed. Therefore, our results suggest that sex chromosome chromatin has a unique character that facilitates its meiotic expression when its continuity is lost, regardless of whether or not it is synapsed.
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Affiliation(s)
- Yisrael Rappaport
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Hanna Achache
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Roni Falk
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Omer Murik
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Oren Ram
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yonatan B Tzur
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.
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13
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Achache H, Falk R, Lerner N, Beatus T, Tzur YB. Oocyte aging is controlled by mitogen-activated protein kinase signaling. Aging Cell 2021; 20:e13386. [PMID: 34061407 PMCID: PMC8208789 DOI: 10.1111/acel.13386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 03/25/2021] [Accepted: 05/08/2021] [Indexed: 12/11/2022] Open
Abstract
Oogenesis is one of the first processes to fail during aging. In women, most oocytes cannot successfully complete meiotic divisions already during the fourth decade of life. Studies of the nematode Caenorhabditis elegans have uncovered conserved genetic pathways that control lifespan, but our knowledge regarding reproductive aging in worms and humans is limited. Specifically, little is known about germline internal signals that dictate the oogonial biological clock. Here, we report a thorough characterization of the changes in the worm germline during aging. We found that shortly after ovulation halts, germline proliferation declines, while apoptosis continues, leading to a gradual reduction in germ cell numbers. In late aging stages, we observed that meiotic progression is disturbed and crossover designation and DNA double-strand break repair decrease. In addition, we detected a decline in the quality of mature oocytes during aging, as reflected by decreasing size and elongation of interhomolog distance, a phenotype also observed in human oocytes. Many of these altered processes were previously attributed to MAPK signaling variations in young worms. In support of this, we observed changes in activation dynamics of MPK-1 during aging. We therefore tested the hypothesis that MAPK controls oocyte quality in aged worms using both genetic and pharmacological tools. We found that in mutants with high levels of activated MPK-1, oocyte quality deteriorates more rapidly than in wild-type worms, whereas reduction of MPK-1 levels enhances quality. Thus, our data suggest that MAPK signaling controls germline aging and could be used to attenuate the rate of oogenesis quality decline.
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Affiliation(s)
- Hanna Achache
- Department of GeneticsInstitute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
| | - Roni Falk
- Department of GeneticsInstitute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
| | - Noam Lerner
- Department of NeurobiologyThe Institute of Life ScienceThe Hebrew University of JerusalemJerusalemIsrael
- The Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringThe Hebrew University of JerusalemJerusalemIsrael
| | - Tsevi Beatus
- Department of NeurobiologyThe Institute of Life ScienceThe Hebrew University of JerusalemJerusalemIsrael
- The Alexander Grass Center for BioengineeringThe Rachel and Selim Benin School of Computer Science and EngineeringThe Hebrew University of JerusalemJerusalemIsrael
| | - Yonatan B. Tzur
- Department of GeneticsInstitute of Life SciencesThe Hebrew University of JerusalemJerusalemIsrael
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14
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Gartner A, Engebrecht J. DNA repair, recombination, and damage signaling. Genetics 2021; 220:6522877. [PMID: 35137093 PMCID: PMC9097270 DOI: 10.1093/genetics/iyab178] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 10/10/2021] [Indexed: 01/09/2023] Open
Abstract
DNA must be accurately copied and propagated from one cell division to the next, and from one generation to the next. To ensure the faithful transmission of the genome, a plethora of distinct as well as overlapping DNA repair and recombination pathways have evolved. These pathways repair a large variety of lesions, including alterations to single nucleotides and DNA single and double-strand breaks, that are generated as a consequence of normal cellular function or by external DNA damaging agents. In addition to the proteins that mediate DNA repair, checkpoint pathways have also evolved to monitor the genome and coordinate the action of various repair pathways. Checkpoints facilitate repair by mediating a transient cell cycle arrest, or through initiation of cell suicide if DNA damage has overwhelmed repair capacity. In this chapter, we describe the attributes of Caenorhabditis elegans that facilitate analyses of DNA repair, recombination, and checkpoint signaling in the context of a whole animal. We review the current knowledge of C. elegans DNA repair, recombination, and DNA damage response pathways, and their role during development, growth, and in the germ line. We also discuss how the analysis of mutational signatures in C. elegans is helping to inform cancer mutational signatures in humans.
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Affiliation(s)
- Anton Gartner
- Department for Biological Sciences, IBS Center for Genomic Integrity, Ulsan National Institute of Science and Technology, Ulsan 689-798, Republic of Korea,Corresponding author: (A.G.); (J.E.)
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis, Davis, CA 95616, USA,Corresponding author: (A.G.); (J.E.)
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15
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Li Q, Hariri S, Engebrecht J. Meiotic Double-Strand Break Processing and Crossover Patterning Are Regulated in a Sex-Specific Manner by BRCA1-BARD1 in Caenorhabditis elegans. Genetics 2020; 216:359-379. [PMID: 32796008 PMCID: PMC7536853 DOI: 10.1534/genetics.120.303292] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 08/08/2020] [Indexed: 12/29/2022] Open
Abstract
Meiosis is regulated in a sex-specific manner to produce two distinct gametes, sperm and oocytes, for sexual reproduction. To determine how meiotic recombination is regulated in spermatogenesis, we analyzed the meiotic phenotypes of mutants in the tumor suppressor E3 ubiquitin ligase BRC-1-BRD-1 complex in Caenorhabditis elegans male meiosis. Unlike in mammals, this complex is not required for meiotic sex chromosome inactivation, the process whereby hemizygous sex chromosomes are transcriptionally silenced. Interestingly, brc-1 and brd-1 mutants show meiotic recombination phenotypes that are largely opposing to those previously reported for female meiosis. Fewer meiotic recombination intermediates marked by the recombinase RAD-51 were observed in brc-1 and brd-1 mutants, and the reduction in RAD-51 foci could be suppressed by mutation of nonhomologous-end-joining proteins. Analysis of GFP::RPA-1 revealed fewer foci in the brc-1brd-1 mutant and concentration of BRC-1-BRD-1 to sites of meiotic recombination was dependent on DNA end resection, suggesting that the complex regulates the processing of meiotic double-strand breaks to promote repair by homologous recombination. Further, BRC-1-BRD-1 is important to promote progeny viability when male meiosis is perturbed by mutations that block the pairing and synapsis of different chromosome pairs, although the complex is not required to stabilize the RAD-51 filament as in female meiosis under the same conditions. Analyses of crossover designation and formation revealed that BRC-1-BRD-1 inhibits supernumerary COs when meiosis is perturbed. Together, our findings suggest that BRC-1-BRD-1 regulates different aspects of meiotic recombination in male and female meiosis.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, California 95616
| | - Sara Hariri
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, California 95616
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, and Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, California 95616
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16
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Targeted Central Nervous System Irradiation of Caenorhabditis elegans Induces a Limited Effect on Motility. BIOLOGY 2020; 9:biology9090289. [PMID: 32937967 PMCID: PMC7564402 DOI: 10.3390/biology9090289] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/09/2020] [Accepted: 09/10/2020] [Indexed: 12/29/2022]
Abstract
To clarify the tissue responsible for a biological function, that function can be experimentally perturbed by an external stimulus, such as radiation. Radiation can be precisely and finely administered and any subsequent change in function examined. To investigate the involvement of the central nervous system (CNS) in Caenorhabditis elegans’ locomotion, we irradiated a limited 20-µm-diameter area of the CNS with a single dose and evaluated the resulting effects on motility. However, whether irradiated area (beam size)-dependent or dose-dependent effects on motility occur via targeted irradiation remain unknown. In the present study, we examined the irradiated area- and dose-dependent effects of CNS-targeted irradiation on the motility of C. elegans using a collimating microbeam system and confirmed the involvement of the CNS and body-wall muscle cells around the CNS in motility. After CNS-targeted microbeam irradiation, C. elegans’ motility was assayed. The results demonstrated a dose-dependent effect of CNS-targeted irradiation on motility reflecting direct effects on the irradiated CNS. In addition, when irradiated with 1000-Gy irradiation, irradiated area (beam size)-dependent effects were observed. This method has two technical advantages: Performing a series of on-chip imaging analyses before and after irradiation and targeted irradiation using a distinct ion-beam size.
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17
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Vujin A, Jones SJ, Zetka M. NHJ-1 Is Required for Canonical Nonhomologous End Joining in Caenorhabditis elegans. Genetics 2020; 215:635-651. [PMID: 32457132 PMCID: PMC7337088 DOI: 10.1534/genetics.120.303328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 05/11/2020] [Indexed: 11/18/2022] Open
Abstract
DNA double-strand breaks (DSBs) are a particularly lethal form of DNA damage that must be repaired to restore genomic integrity. Canonical nonhomologous end joining (NHEJ), is a widely conserved pathway that detects and directly ligates the broken ends to repair the DSB. These events globally require the two proteins that form the Ku ring complex, Ku70 and Ku80, and the terminal ligase LIG4. While the NHEJ pathway in vertebrates is elaborated by more than a dozen factors of varying conservation and is similarly complex in other eukaryotes, the entire known NHEJ toolkit in Caenorhabditis elegans consists only of the core components CKU-70, CKU-80, and LIG-4 Here, we report the discovery of the first accessory NHEJ factor in C. elegans Our analysis of the DNA damage response in young larvae revealed that the canonical wild-type N2 strain consisted of two lines that exhibited a differential phenotypic response to ionizing radiation (IR). Following the mapping of the causative locus to a candidate on chromosome V and clustered regularly interspaced short palindromic repeats-Cas9 mutagenesis, we show that disruption of the nhj-1 sequence induces IR sensitivity in the N2 line that previously exhibited IR resistance. Using genetic and cytological analyses, we demonstrate that nhj-1 functions in the NHEJ pathway to repair DSBs. Double mutants of nhj-1 and lig-4 or cku-80 do not exhibit additive IR sensitivity, and the post-IR somatic and fertility phenotypes of nhj-1 mimic those of the other NHEJ factors. Furthermore, in com-1 mutants that permit repair of meiotic DSBs by NHEJ instead of restricting their repair to the homologous recombination pathway, loss of nhj-1 mimics the consequences of loss of lig-4 Diakinesis-stage nuclei in nhj-1; com-1 and nhj-1; lig-4 mutant germlines exhibit increased numbers of DAPI-staining bodies, consistent with increased chromosome fragmentation in the absence of NHEJ-mediated meiotic DSB repair. Finally, we show that NHJ-1 and LIG-4 localize to somatic nuclei in larvae, but are excluded from the germline progenitor cells, consistent with NHEJ being the dominant DNA repair pathway in the soma. nhj-1 shares no sequence homology with other known eukaryotic NHEJ factors and is taxonomically restricted to the Rhabditid family, underscoring the evolutionary plasticity of even highly conserved pathways.
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Affiliation(s)
- Aleksandar Vujin
- Department of Biology, McGill University, Montreal, Quebec H3K 1M4, Canada
| | - Steven J Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, British Columbia, Canada V5Z 4S6
| | - Monique Zetka
- Department of Biology, McGill University, Montreal, Quebec H3K 1M4, Canada
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18
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In vivo analysis of FANCD2 recruitment at meiotic DNA breaks in Caenorhabditis elegans. Sci Rep 2020; 10:103. [PMID: 31919410 PMCID: PMC6952437 DOI: 10.1038/s41598-019-57096-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/19/2019] [Indexed: 12/28/2022] Open
Abstract
Fanconi Anemia is a rare genetic disease associated with DNA repair defects, congenital abnormalities and infertility. Most of FA pathway is evolutionary conserved, allowing dissection and mechanistic studies in simpler model systems such as Caenorhabditis elegans. In the present study, we employed C. elegans to better understand the role of FA group D2 (FANCD2) protein in vivo, a key player in promoting genome stability. We report that localization of FCD-2/FANCD2 is dynamic during meiotic prophase I and requires its heterodimeric partner FNCI-1/FANCI. Strikingly, we found that FCD-2 recruitment depends on SPO-11-induced double-strand breaks (DSBs) but not RAD-51-mediated strand invasion. Furthermore, exposure to DNA damage-inducing agents boosts FCD-2 recruitment on the chromatin. Finally, analysis of genetic interaction between FCD-2 and BRC-1 (the C. elegans orthologue of mammalian BRCA1) supports a role for these proteins in different DSB repair pathways. Collectively, we showed a direct involvement of FCD-2 at DSBs and speculate on its function in driving meiotic DNA repair.
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19
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Serpe M, Forenza C, Adamo A, Russo N, Perugino G, Ciaramella M, Valenti A. The DNA Alkylguanine DNA Alkyltransferase-2 (AGT-2) Of Caenorhabditis Elegans Is Involved In Meiosis And Early Development Under Physiological Conditions. Sci Rep 2019; 9:6889. [PMID: 31053748 PMCID: PMC6499797 DOI: 10.1038/s41598-019-43394-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
DNA alkylguanine DNA alkyltransferases (AGTs) are evolutionary conserved proteins that repair alkylation damage in DNA, counteracting the effects of agents inducing such lesions. Over the last years AGTs have raised considerable interest for both the peculiarity of their molecular mechanism and their relevance in cancer biology. AGT knock out mice show increased tumour incidence in response to alkylating agents, and over-expression of the human AGT protein in cancer cells is frequently associated with resistance to alkylating chemotherapy. While all data available point to a function of AGT proteins in the cell response to alkylation lesions, we report for the first time that one of the two AGT paralogs of the model organism C. elegans, called AGT-2, also plays unexpected roles in meiosis and early development under physiological conditions. Our data suggest a role for AGT-2 in conversion of homologous recombination intermediates into post-strand exchange products in meiosis, and show that agt-2 gene down-regulation, or treatment of animals with an AGT inhibitor results in increased number of germ cells that are incompatible with producing viable offspring and are eliminated by apoptosis. These results suggest possible functions for AGTs in cell processes distinct from repair of alkylating damage.
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Affiliation(s)
- Mario Serpe
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy
| | - Chiara Forenza
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy
| | - Adele Adamo
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy
| | - Noemi Russo
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy
| | - Giuseppe Perugino
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy
| | - Maria Ciaramella
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy
| | - Anna Valenti
- Institute of Biosciences and BioResources, National Research Council of Italy, Via Pietro Castellino 111, Naples, 80131, Italy.
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20
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Achache H, Laurent L, Hecker-Mimoun Y, Ishtayeh H, Rappaport Y, Kroizer E, Colaiácovo MP, Tzur YB. Progression of Meiosis Is Coordinated by the Level and Location of MAPK Activation Via OGR-2 in Caenorhabditis elegans. Genetics 2019; 212:213-229. [PMID: 30867196 PMCID: PMC6499523 DOI: 10.1534/genetics.119.302080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 03/07/2019] [Indexed: 02/07/2023] Open
Abstract
During meiosis, a series of evolutionarily conserved events allow for reductional chromosome division, which is required for sexual reproduction. Although individual meiotic processes have been extensively studied, we currently know far less about how meiosis is regulated and coordinated. In the Caenorhabditis elegans gonad, mitogen-activated protein kinase (MAPK) signaling drives oogenesis while undergoing spatial activation and deactivation waves. However, it is currently unclear how MAPK activation is governed and how it facilitates the progression of oogenesis. Here, we show that the oocyte and germline-related 2 (ogr-2) gene affects proper progression of oogenesis. Complete deletion of ogr-2 results in delayed meiotic entry and late spatial onset of double-strand break repair. Elevated levels of apoptosis are observed in this mutant, independent of the meiotic canonical checkpoints; however, they are dependent on the MAPK terminal member MPK-1/ERK. MPK-1 activation is elevated in diplotene in ogr-2 mutants and its aberrant spatial activation correlates with stages where meiotic progression defects are evident. Deletion of ogr-2 significantly reduces the expression of lip-1, a phosphatase reported to repress MPK-1, which is consistent with OGR-2 localization at chromatin in germ cells. We suggest that OGR-2 modulates the expression of lip-1 to promote the timely progression of meiosis through MPK-1 spatial deactivation.
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Affiliation(s)
- Hanna Achache
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | - Lévana Laurent
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | - Yaël Hecker-Mimoun
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | - Hasan Ishtayeh
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | - Yisrael Rappaport
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | - Eitan Kroizer
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
| | | | - Yonatan B Tzur
- Department of Genetics, Institute of Life Sciences, Hebrew University, Givat-Ram, Jerusalem 91904, Israel
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21
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Roelens B, Zawadzki KA, Villeneuve AM. me101 is a new allele of rad-51. MICROPUBLICATION BIOLOGY 2019; 2019:10.17912/micropub.biology.000107. [PMID: 32550442 PMCID: PMC7252318 DOI: 10.17912/micropub.biology.000107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Baptiste Roelens
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine
| | - Karl A Zawadzki
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine
| | - Anne M Villeneuve
- Departments of Developmental Biology and Genetics, Stanford University School of Medicine,
Correspondence to: Anne M Villeneuve ()
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22
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Li Q, Saito TT, Martinez-Garcia M, Deshong AJ, Nadarajan S, Lawrence KS, Checchi PM, Colaiacovo MP, Engebrecht J. The tumor suppressor BRCA1-BARD1 complex localizes to the synaptonemal complex and regulates recombination under meiotic dysfunction in Caenorhabditis elegans. PLoS Genet 2018; 14:e1007701. [PMID: 30383767 PMCID: PMC6211623 DOI: 10.1371/journal.pgen.1007701] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022] Open
Abstract
Breast cancer susceptibility gene 1 (BRCA1) and binding partner BRCA1-associated RING domain protein 1 (BARD1) form an essential E3 ubiquitin ligase important for DNA damage repair and homologous recombination. The Caenorhabditis elegans orthologs, BRC-1 and BRD-1, also function in DNA damage repair, homologous recombination, as well as in meiosis. Using functional GFP fusions we show that in mitotically-dividing germ cells BRC-1 and BRD-1 are nucleoplasmic with enrichment at foci that partially overlap with the recombinase RAD-51. Co-localization with RAD-51 is enhanced under replication stress. As cells enter meiosis, BRC-1-BRD-1 remains nucleoplasmic and in foci, and beginning in mid-pachytene the complex co-localizes with the synaptonemal complex. Following establishment of the single asymmetrically positioned crossover on each chromosome pair, BRC-1-BRD-1 concentrates to the short arm of the bivalent. Localization dependencies reveal that BRC-1 and BRD-1 are interdependent and the complex fails to properly localize in both meiotic recombination and chromosome synapsis mutants. Consistent with a role for BRC-1-BRD-1 in meiotic recombination in the context of the synaptonemal complex, inactivation of BRC-1 or BRD-1 enhances the embryonic lethality of mutants defective in chromosome synapsis. Our data suggest that under meiotic dysfunction, BRC-1-BRD-1 stabilizes the RAD-51 filament and alters the recombination landscape; these two functions can be genetically separated from BRC-1-BRD-1's role in the DNA damage response. Together, we propose that BRC-1-BRD-1 serves a checkpoint function at the synaptonemal complex where it monitors and modulates meiotic recombination.
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Affiliation(s)
- Qianyan Li
- Department of Molecular and Cellular Biology, University of California Davis; Davis CA, United States of America
| | - Takamune T. Saito
- Department of Genetics, Harvard Medical School; Boston, MA, United States of America
| | | | - Alison J. Deshong
- Department of Molecular and Cellular Biology, University of California Davis; Davis CA, United States of America
| | | | - Katherine S. Lawrence
- Department of Molecular and Cellular Biology, University of California Davis; Davis CA, United States of America
| | - Paula M. Checchi
- Department of Molecular and Cellular Biology, University of California Davis; Davis CA, United States of America
| | - Monica P. Colaiacovo
- Department of Genetics, Harvard Medical School; Boston, MA, United States of America
| | - JoAnne Engebrecht
- Department of Molecular and Cellular Biology, University of California Davis; Davis CA, United States of America
- * E-mail:
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23
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BRCA1-BARD1 associate with the synaptonemal complex and pro-crossover factors and influence RAD-51 dynamics during Caenorhabditis elegans meiosis. PLoS Genet 2018; 14:e1007653. [PMID: 30383754 PMCID: PMC6211622 DOI: 10.1371/journal.pgen.1007653] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 08/23/2018] [Indexed: 11/19/2022] Open
Abstract
During meiosis, the maternal and paternal homologous chromosomes must align along their entire length and recombine to achieve faithful segregation in the gametes. Meiotic recombination is accomplished through the formation of DNA double-strand breaks, a subset of which can mature into crossovers to link the parental homologous chromosomes and promote their segregation. Breast and ovarian cancer susceptibility protein BRCA1 and its heterodimeric partner BARD1 play a pivotal role in DNA repair in mitotic cells; however, their functions in gametogenesis are less well understood. Here we show that localization of BRC-1 and BRD-1 (Caenorhabditis elegans orthologues of BRCA1 and BARD1) is dynamic during meiotic prophase I; they ultimately becoming concentrated at regions surrounding the presumptive crossover sites, co-localizing with the pro-crossover factors COSA-1, MSH-5 and ZHP-3. The synaptonemal complex and PLK-2 activity are essential for recruitment of BRC-1 to chromosomes and its subsequent redistribution towards the short arm of the bivalent. BRC-1 and BRD-1 form in vivo complexes with the synaptonemal complex component SYP-3 and the crossover-promoting factor MSH-5. Furthermore, BRC-1 is essential for efficient stage-specific recruitment/stabilization of the RAD-51 recombinase to DNA damage sites when synapsis is impaired and upon induction of exogenous damage. Taken together, our data provide new insights into the localization and meiotic function of the BRC-1-BRD-1 complex and highlight its essential role in DNA double-strand break repair during gametogenesis.
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24
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Macaisne N, Kessler Z, Yanowitz JL. Meiotic Double-Strand Break Proteins Influence Repair Pathway Utilization. Genetics 2018; 210:843-856. [PMID: 30242011 PMCID: PMC6218235 DOI: 10.1534/genetics.118.301402] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 09/13/2018] [Indexed: 12/13/2022] Open
Abstract
Double-strand breaks (DSBs) are among the most deleterious lesions DNA can endure. Yet, DSBs are programmed at the onset of meiosis, and are required to facilitate appropriate reduction of ploidy in daughter cells. Repair of these breaks is tightly controlled to favor homologous recombination (HR)-the only repair pathway that can form crossovers. However, little is known about how the activities of alternative repair pathways are regulated at these stages. We discovered an unexpected synthetic interaction between the DSB machinery and strand-exchange proteins. Depleting the Caenorhabditis elegans DSB-promoting factors HIM-5 and DSB-2 suppresses the formation of chromosome fusions that arise in the absence of RAD-51 or other strand-exchange mediators. Our investigations reveal that nonhomologous and theta-mediated end joining (c-NHEJ and TMEJ, respectively) and single strand annealing (SSA) function redundantly to repair DSBs when HR is compromised, and that HIM-5 influences the utilization of TMEJ and SSA.
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Affiliation(s)
- Nicolas Macaisne
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pennsylvania 15213
| | - Zebulin Kessler
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pennsylvania 15213
| | - Judith L Yanowitz
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pennsylvania 15213
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25
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Germoglio M, Adamo A. A Role in Apoptosis Regulation for the rad-51 Gene of Caenorhabditis elegans. Genetics 2018; 209:1017-1028. [PMID: 29884745 PMCID: PMC6063241 DOI: 10.1534/genetics.118.301152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 06/05/2018] [Indexed: 02/07/2023] Open
Abstract
The evolutionarily conserved RAD-51 protein is essential for homologous recombination in the germ line as well as homologous repair of DNA double-strand breaks in all eukaryotic cells. In the nematode Caenorhabditis elegans, the rad-51 gene is transcribed into messenger RNAs potentially coding three alternative protein isoforms. Null rad-51 alleles display embryonic lethality, severe defects in chromosome structure, and high levels of germ line apoptosis. To dissect its functions, we genetically modified the C. elegans rad-51 gene by clustered regularly interspaced short palindromic repeats/Cas9 genome-editing technology, obtaining a separation-of-function (sfi-) mutant allele that only disrupts the long-transcript isoform. This mutant shows no defects in an otherwise wild-type meiosis and is able to activate physiological germ cell death, which occurs at the late pachytene stage. However, although the mutant is competent in DNA damage checkpoint activation after exposure to ionizing radiation, it is defective for induction of DNA damage-induced apoptosis in meiotic germ cells. These results suggest that RAD-51 plays a novel role in germ line apoptosis independent of RAD-51-mediated strand invasion for homologous recombination.
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Affiliation(s)
- Marcello Germoglio
- Institute of Biosciences and BioResources, National Research Council, 80131 Naples, Italy
- University of Campania "Luigi Vanvitelli," 81100 Caserta, Italy
| | - Adele Adamo
- Institute of Biosciences and BioResources, National Research Council, 80131 Naples, Italy
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26
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Papaluca A, Wagner JR, Saragovi HU, Ramotar D. UNG-1 and APN-1 are the major enzymes to efficiently repair 5-hydroxymethyluracil DNA lesions in C. elegans. Sci Rep 2018; 8:6860. [PMID: 29717169 PMCID: PMC5931555 DOI: 10.1038/s41598-018-25124-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/13/2018] [Indexed: 11/16/2022] Open
Abstract
In Caenorhabditis elegans, two DNA glycosylases, UNG-1 and NTH-1, and two AP endonucleases, APN-1 and EXO-3, have been characterized from the base-excision repair (BER) pathway that repairs oxidatively modified DNA bases. UNG-1 removes uracil, while NTH-1 can remove 5-hydroxymethyluracil (5-hmU), an oxidation product of thymine, as well as other lesions. Both APN-1 and EXO-3 can incise AP sites and remove 3′-blocking lesions at DNA single strand breaks, and only APN-1 possesses 3′- to 5′-exonulease and nucleotide incision repair activities. We used C. elegans mutants to study the role of the BER pathway in processing 5-hmU. We observe that ung-1 mutants exhibited a decrease in brood size and lifespan, and an elevated level of germ cell apoptosis when challenged with 5-hmU. These phenotypes were exacerbated by RNAi downregulation of apn-1 in the ung-1 mutant. The nth-1 or exo-3 mutants displayed wild type phenotypes towards 5-hmU. We show that partially purified UNG-1 can act on 5-hmU lesion in vitro. We propose that UNG-1 removes 5-hmU incorporated into the genome and the resulting AP site is cleaved by APN-1 or EXO-3. In the absence of UNG-1, the 5-hmU is removed by NTH-1 creating a genotoxic 3′-blocking lesion that requires the action of APN-1.
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Affiliation(s)
- Arturo Papaluca
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Department of Medicine, 5415 Boul. de l'Assomption, Montréal, Québec, H1T2M4, Canada.,Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Department of Pharmacology and Therapeutics, McGill University, Department of Pharmacology and Therapeutics, 3755 Chemin de la Côte Sainte-Catherine, Québec, Montréal, H3T1E2, Canada
| | - J Richard Wagner
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, 3001 12 Avenue Nord, Sherbrooke, Québec, J1H5N4, Canada
| | - H Uri Saragovi
- Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Department of Pharmacology and Therapeutics, McGill University, Department of Pharmacology and Therapeutics, 3755 Chemin de la Côte Sainte-Catherine, Québec, Montréal, H3T1E2, Canada
| | - Dindial Ramotar
- Maisonneuve-Rosemont Hospital, Research Center, Université de Montréal, Department of Medicine, 5415 Boul. de l'Assomption, Montréal, Québec, H1T2M4, Canada.
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27
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Kurzbauer MT, Pradillo M, Kerzendorfer C, Sims J, Ladurner R, Oliver C, Janisiw MP, Mosiolek M, Schweizer D, Copenhaver GP, Schlögelhofer P. Arabidopsis thaliana FANCD2 Promotes Meiotic Crossover Formation. THE PLANT CELL 2018; 30:415-428. [PMID: 29352063 PMCID: PMC5868695 DOI: 10.1105/tpc.17.00745] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/06/2017] [Accepted: 01/17/2018] [Indexed: 05/18/2023]
Abstract
Fanconi anemia (FA) is a human autosomal recessive disorder characterized by chromosomal instability, developmental pathologies, predisposition to cancer, and reduced fertility. So far, 19 genes have been implicated in FA, most of them involved in DNA repair. Some are conserved across higher eukaryotes, including plants. The Arabidopsis thaliana genome encodes a homolog of the Fanconi anemia D2 gene (FANCD2) whose function in DNA repair is not yet fully understood. Here, we provide evidence that AtFANCD2 is required for meiotic homologous recombination. Meiosis is a specialized cell division that ensures reduction of genomic content by half and DNA exchange between homologous chromosomes via crossovers (COs) prior to gamete formation. In plants, a mutation in AtFANCD2 results in a 14% reduction of CO numbers. Genetic analysis demonstrated that AtFANCD2 acts in parallel to both MUTS HOMOLOG4 (AtMSH4), known for its role in promoting interfering COs and MMS AND UV SENSITIVE81 (AtMUS81), known for its role in the formation of noninterfering COs. AtFANCD2 promotes noninterfering COs in a MUS81-independent manner and is therefore part of an uncharted meiotic CO-promoting mechanism, in addition to those described previously.
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Affiliation(s)
- Marie-Therese Kurzbauer
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Claudia Kerzendorfer
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Jason Sims
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Rene Ladurner
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, 1030 Vienna, Austria
| | - Cecilia Oliver
- Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Michael Peter Janisiw
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
| | - Magdalena Mosiolek
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, 1030 Vienna, Austria
| | - Dieter Schweizer
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, 1030 Vienna, Austria
| | - 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
| | - Peter Schlögelhofer
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, 1030 Vienna, Austria
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28
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Abstract
Sexual reproduction requires the production of haploid gametes (sperm and egg) with only one copy of each chromosome; fertilization then restores the diploid chromosome content in the next generation. This reduction in genetic content is accomplished during a specialized cell division called meiosis, in which two rounds of chromosome segregation follow a single round of DNA replication. In preparation for the first meiotic division, homologous chromosomes pair and synapse, creating a context that promotes formation of crossover recombination events. These crossovers, in conjunction with sister chromatid cohesion, serve to connect the two homologs and facilitate their segregation to opposite poles during the first meiotic division. During the second meiotic division, which is similar to mitosis, sister chromatids separate; the resultant products are haploid cells that become gametes. In Caenorhabditis elegans (and most other eukaryotes) homologous pairing and recombination are required for proper chromosome inheritance during meiosis; accordingly, the events of meiosis are tightly coordinated to ensure the proper execution of these events. In this chapter, we review the seminal events of meiosis: pairing of homologous chromosomes, the changes in chromosome structure that chromosomes undergo during meiosis, the events of meiotic recombination, the differentiation of homologous chromosome pairs into structures optimized for proper chromosome segregation at Meiosis I, and the ultimate segregation of chromosomes during the meiotic divisions. We also review the regulatory processes that ensure the coordinated execution of these meiotic events during prophase I.
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Affiliation(s)
- Kenneth J Hillers
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA 93407, United States
| | - Verena Jantsch
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter,1030 Vienna, Austria
| | | | - Judith L Yanowitz
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, United States
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29
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Ramezani S, Shirdel A, Rafatpanah H, Akbarin MM, Tarokhian H, Rahimi H, Bari A, Jahantigh HR, Rezaee SA. Assessment of HTLV-1 proviral load, LAT, BIM, c-FOS and RAD51 gene expression in adult T cell leukemia/lymphoma. Med Microbiol Immunol 2017; 206:327-335. [PMID: 28466382 DOI: 10.1007/s00430-017-0506-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 04/17/2017] [Indexed: 12/13/2022]
Abstract
Adult T cell leukemia/lymphoma (ATLL) is a life-threatening malignancy of HTLV-1 infected Th lymphocytes. In the present study host-virus interactions were investigated by assessment of HTLV-1 proviral load (PVL) and host gene expression. A cross-sectional study was carried out on 18 ATLL, 10 HAM/TSP patients and 18 HTLV-1 asymptomatic carriers (ACs). DNA and mRNA of the peripheral blood mononuclear cells were extracted for PVL and LAT, BIM, c-FOS and RAD51 gene expression measurement using qRT-PCR. The mean PVL in ATLL patients was 11,430 ± 3770 copies/104 which was statistically higher than ACs, 530 ± 119 copies/104, (p < 0.001). The expression of BIM, and c-FOS in ATLL patients were higher than HTLV-1 ACs; however, there were no statistically significant differences. The expression of RAD51 as an essential player on DNA repair showed around 160 times increase in ATLL group (166 ± 95) compared to ACs (1.04 ± 0.34) which is statistically significant (p < 0.001). Interestingly, there was a positive correlation between RAD51 expression and HTLV-PVL. The expression of LAT as a central adaptor in TCR signaling interestingly was around 36 times higher in ATLL group than ACs (ATLL; 41.33 ± 19.91 vs. ACs; 1.15 ± 0.22, p < 0.001). This finding showed that TCR signaling pathway mainly provides the growth factors for transformed cells. Furthermore, the overexpression of RAD51 which has been induced in HTLV-1 infected cells as a consequence of virus replication is not able to overcome the DNA damage toward cell transformation.
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Affiliation(s)
- Samaneh Ramezani
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran
| | - Abbas Shirdel
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran.,Hematology and Oncology Department, Ghaem Hospital, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Houshang Rafatpanah
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran
| | - Mohammad Mehdi Akbarin
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran
| | - Hanieh Tarokhian
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran
| | - Hossein Rahimi
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran.,Hematology and Oncology Department, Ghaem Hospital, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alireza Bari
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran.,Hematology and Oncology Department, Ghaem Hospital, Medical School, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid Reza Jahantigh
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran
| | - Seyed Abdolrahim Rezaee
- Immunology Research Center, Inflammation and Inflammatory Diseases Division, Medical School, Mashhad University of Medical Sciences, Azadi-Square, Medical Campus, 9177948564, Mashhad, Iran.
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30
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McClendon TB, Mainpal R, Amrit FRG, Krause MW, Ghazi A, Yanowitz JL. X Chromosome Crossover Formation and Genome Stability in Caenorhabditis elegans Are Independently Regulated by xnd-1. G3 (BETHESDA, MD.) 2016; 6:3913-3925. [PMID: 27678523 PMCID: PMC5144962 DOI: 10.1534/g3.116.035725] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 09/21/2016] [Indexed: 01/19/2023]
Abstract
The germ line efficiently combats numerous genotoxic insults to ensure the high fidelity propagation of unaltered genomic information across generations. Yet, germ cells in most metazoans also intentionally create double-strand breaks (DSBs) to promote DNA exchange between parental chromosomes, a process known as crossing over. Homologous recombination is employed in the repair of both genotoxic lesions and programmed DSBs, and many of the core DNA repair proteins function in both processes. In addition, DNA repair efficiency and crossover (CO) distribution are both influenced by local and global differences in chromatin structure, yet the interplay between chromatin structure, genome integrity, and meiotic fidelity is still poorly understood. We have used the xnd-1 mutant of Caenorhabditis elegans to explore the relationship between genome integrity and crossover formation. Known for its role in ensuring X chromosome CO formation and germ line development, we show that xnd-1 also regulates genome stability. xnd-1 mutants exhibited a mortal germ line, high embryonic lethality, high incidence of males, and sensitivity to ionizing radiation. We discovered that a hypomorphic allele of mys-1 suppressed these genome instability phenotypes of xnd-1, but did not suppress the CO defects, suggesting it serves as a separation-of-function allele. mys-1 encodes a histone acetyltransferase, whose homolog Tip60 acetylates H2AK5, a histone mark associated with transcriptional activation that is increased in xnd-1 mutant germ lines, raising the possibility that thresholds of H2AK5ac may differentially influence distinct germ line repair events. We also show that xnd-1 regulated him-5 transcriptionally, independently of mys-1, and that ectopic expression of him-5 suppressed the CO defects of xnd-1 Our work provides xnd-1 as a model in which to study the link between chromatin factors, gene expression, and genome stability.
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Affiliation(s)
- T Brooke McClendon
- Molecular Genetics and Developmental Biology Graduate Program, University of Pittsburgh School of Medicine, Pennsylvania
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Services University of Pittsburgh School of Medicine, Pennsylvania 15213
| | - Rana Mainpal
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Services University of Pittsburgh School of Medicine, Pennsylvania 15213
| | - Francis R G Amrit
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pennsylvania 15224
| | - Michael W Krause
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892
| | - Arjumand Ghazi
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pennsylvania 15224
| | - Judith L Yanowitz
- Molecular Genetics and Developmental Biology Graduate Program, University of Pittsburgh School of Medicine, Pennsylvania
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Services University of Pittsburgh School of Medicine, Pennsylvania 15213
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31
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A novel approach using C. elegans DNA damage-induced apoptosis to characterize the dynamics of uptake transporters for therapeutic drug discoveries. Sci Rep 2016; 6:36026. [PMID: 27786254 PMCID: PMC5081529 DOI: 10.1038/srep36026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 10/10/2016] [Indexed: 11/08/2022] Open
Abstract
Organic cation transporter (OCT) function is critical for cellular homeostasis. C. elegans lacking OCT-1 displays a shortened lifespan and increased susceptibility to oxidative stress. We show that these phenotypes can be rescued by downregulating the OCT-1 paralogue, OCT-2. Herein, we delineate a biochemical pathway in C. elegans where uptake of genotoxic chemotherapeutics such as doxorubicin and cisplatin, and subsequent DNA damage-induced apoptosis of germ cells, are dependent exclusively upon OCT-2. We characterized OCT-2 as the main uptake transporter for doxorubicin, as well as a number of other therapeutic agents and chemical compounds, some identified through ligand-protein docking analyses. We provide insights into the conserved features of the structure and function and gene regulation of oct-1 and oct-2 in distinct tissues of C. elegans. Importantly, our innovative approach of exploiting C. elegans uptake transporters in combination with defective DNA repair pathways will have broad applications in medicinal chemistry.
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32
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Kulkarni A, Lightfoot JW, Streit A. Germline organization in Strongyloides nematodes reveals alternative differentiation and regulation mechanisms. Chromosoma 2016; 125:725-45. [PMID: 26661737 PMCID: PMC5023735 DOI: 10.1007/s00412-015-0562-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 11/15/2015] [Accepted: 11/16/2015] [Indexed: 11/14/2022]
Abstract
Nematodes of the genus Strongyloides are important parasites of vertebrates including man. Currently, little is known about their germline organization or reproductive biology and how this influences their parasitic life strategies. Here, we analyze the structure of the germline in several Strongyloides and closely related species and uncover striking differences in the development, germline organization, and fluid dynamics compared to the model organism Caenorhabditis elegans. With a focus on Strongyloides ratti, we reveal that the proliferation of germ cells is restricted to early and mid-larval development, thus limiting the number of progeny. In order to understand key germline events (specifically germ cell progression and the transcriptional status of the germline), we monitored conserved histone modifications, in particular H3Pser10 and H3K4me3. The evolutionary significance of these events is subsequently highlighted through comparisons with six other nematode species, revealing underlying complexities and variations in the development of the germline among nematodes.
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Affiliation(s)
- Arpita Kulkarni
- Department Evolutionary Biology, Max Planck Institute for Developmental Biology, D-72076, Tübingen, Germany
| | - James W Lightfoot
- Department Evolutionary Biology, Max Planck Institute for Developmental Biology, D-72076, Tübingen, Germany
| | - Adrian Streit
- Department Evolutionary Biology, Max Planck Institute for Developmental Biology, D-72076, Tübingen, Germany.
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33
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The p53-like Protein CEP-1 Is Required for Meiotic Fidelity in C. elegans. Curr Biol 2016; 26:1148-58. [PMID: 27151662 DOI: 10.1016/j.cub.2016.03.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 02/05/2016] [Accepted: 03/14/2016] [Indexed: 11/21/2022]
Abstract
The passage of genetic information during meiosis requires exceptionally high fidelity to prevent birth defects and infertility. Accurate chromosome segregation during the first meiotic division relies on the formation of crossovers between homologous chromosomes and a series of precisely controlled steps to exchange genetic information. Many studies have hinted at a role for p53 in meiosis, but how it functions in this process is poorly understood. Here, we have identified a cooperative role for the p53-like protein CEP-1 and the meiotic protein HIM-5 in maintaining genome stability in the C. elegans germline. Loss of cep-1 and him-5 results in synthetic lethality that is dependent on the upstream DNA damage checkpoint but independent of the downstream core apoptotic pathway. We show that this synthetic lethality is the result of defective crossover formation due to reduced SPO-11-dependent double-strand breaks. Using cep-1 separation-of-function alleles, we show that cep-1 and him-5 also suppress inappropriate activation of the nonhomologous end joining (NHEJ) pathway. This work reveals an ancestral function for the p53 family in ensuring the fidelity of meiosis and establishes CEP-1 as a critical determinant of repair pathway choice.
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34
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Meiotic recombination and the crossover assurance checkpoint in Caenorhabditis elegans. Semin Cell Dev Biol 2016; 54:106-16. [PMID: 27013114 DOI: 10.1016/j.semcdb.2016.03.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/16/2016] [Indexed: 12/13/2022]
Abstract
During meiotic prophase, chromosomes pair and synapse with their homologs and undergo programmed DNA double-strand break (DSB) formation to initiate meiotic recombination. These DSBs are processed to generate a limited number of crossover recombination products on each chromosome, which are essential to ensure faithful segregation of homologous chromosomes. The nematode Caenorhabditis elegans has served as an excellent model organism to investigate the mechanisms that drive and coordinate these chromosome dynamics during meiosis. Here we focus on our current understanding of the regulation of DSB induction in C. elegans. We also review evidence that feedback regulation of crossover formation prolongs the early stages of meiotic prophase, and discuss evidence that this can alter the recombination pattern, most likely by shifting the genome-wide distribution of DSBs.
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35
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Hong Y, Sonneville R, Agostinho A, Meier B, Wang B, Blow JJ, Gartner A. The SMC-5/6 Complex and the HIM-6 (BLM) Helicase Synergistically Promote Meiotic Recombination Intermediate Processing and Chromosome Maturation during Caenorhabditis elegans Meiosis. PLoS Genet 2016; 12:e1005872. [PMID: 27010650 PMCID: PMC4807058 DOI: 10.1371/journal.pgen.1005872] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/25/2016] [Indexed: 11/19/2022] Open
Abstract
Meiotic recombination is essential for the repair of programmed double strand breaks (DSBs) to generate crossovers (COs) during meiosis. The efficient processing of meiotic recombination intermediates not only needs various resolvases but also requires proper meiotic chromosome structure. The Smc5/6 complex belongs to the structural maintenance of chromosome (SMC) family and is closely related to cohesin and condensin. Although the Smc5/6 complex has been implicated in the processing of recombination intermediates during meiosis, it is not known how Smc5/6 controls meiotic DSB repair. Here, using Caenorhabditis elegans we show that the SMC-5/6 complex acts synergistically with HIM-6, an ortholog of the human Bloom syndrome helicase (BLM) during meiotic recombination. The concerted action of the SMC-5/6 complex and HIM-6 is important for processing recombination intermediates, CO regulation and bivalent maturation. Careful examination of meiotic chromosomal morphology reveals an accumulation of inter-chromosomal bridges in smc-5; him-6 double mutants, leading to compromised chromosome segregation during meiotic cell divisions. Interestingly, we found that the lethality of smc-5; him-6 can be rescued by loss of the conserved BRCA1 ortholog BRC-1. Furthermore, the combined deletion of smc-5 and him-6 leads to an irregular distribution of condensin and to chromosome decondensation defects reminiscent of condensin depletion. Lethality conferred by condensin depletion can also be rescued by BRC-1 depletion. Our results suggest that SMC-5/6 and HIM-6 can synergistically regulate recombination intermediate metabolism and suppress ectopic recombination by controlling chromosome architecture during meiosis.
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Affiliation(s)
- Ye Hong
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Remi Sonneville
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Ana Agostinho
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Bettina Meier
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Bin Wang
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - J. Julian Blow
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - Anton Gartner
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
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Cortez MA, Valdecanas D, Niknam S, Peltier HJ, Diao L, Giri U, Komaki R, Calin GA, Gomez DR, Chang JY, Heymach JV, Bader AG, Welsh JW. In Vivo Delivery of miR-34a Sensitizes Lung Tumors to Radiation Through RAD51 Regulation. MOLECULAR THERAPY. NUCLEIC ACIDS 2015; 4:e270. [PMID: 26670277 PMCID: PMC5014539 DOI: 10.1038/mtna.2015.47] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/11/2015] [Indexed: 01/20/2023]
Abstract
MiR-34a, an important tumor-suppressing microRNA, is downregulated in several types of cancer; loss of its expression has been linked with unfavorable clinical outcomes in non-small-cell lung cancer (NSCLC), among others. MiR-34a represses several key oncogenic proteins, and a synthetic mimic of miR-34a is currently being tested in a cancer trial. However, little is known about the potential role of miR-34a in regulating DNA damage response and repair. Here, we demonstrate that miR-34a directly binds to the 3' untranslated region of RAD51 and regulates homologous recombination, inhibiting double-strand-break repair in NSCLC cells. We further demonstrate the therapeutic potential of miR-34a delivery in combination with radiotherapy in mouse models of lung cancer. Collectively, our results suggest that administration of miR-34a in combination with radiotherapy may represent a novel strategy for treating NSCLC.
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Affiliation(s)
- Maria Angelica Cortez
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - David Valdecanas
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Sharareh Niknam
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - Lixia Diao
- Department of Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Uma Giri
- Department of Thoracic/Head & Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ritsuko Komaki
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - George A Calin
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Daniel R Gomez
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Joe Y Chang
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - John Victor Heymach
- Department of Thoracic/Head & Neck Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | | | - James William Welsh
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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Chung G, Rose AM, Petalcorin MIR, Martin JS, Kessler Z, Sanchez-Pulido L, Ponting CP, Yanowitz JL, Boulton SJ. REC-1 and HIM-5 distribute meiotic crossovers and function redundantly in meiotic double-strand break formation in Caenorhabditis elegans. Genes Dev 2015; 29:1969-79. [PMID: 26385965 PMCID: PMC4579353 DOI: 10.1101/gad.266056.115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/26/2015] [Indexed: 01/07/2023]
Abstract
The Caenorhabditis elegans gene rec-1 was the first genetic locus identified in metazoa to affect the distribution of meiotic crossovers along the chromosome. We report that rec-1 encodes a distant paralog of HIM-5, which was discovered by whole-genome sequencing and confirmed by multiple genome-edited alleles. REC-1 is phosphorylated by cyclin-dependent kinase (CDK) in vitro, and mutation of the CDK consensus sites in REC-1 compromises meiotic crossover distribution in vivo. Unexpectedly, rec-1; him-5 double mutants are synthetic-lethal due to a defect in meiotic double-strand break formation. Thus, we uncovered an unexpected robustness to meiotic DSB formation and crossover positioning that is executed by HIM-5 and REC-1 and regulated by phosphorylation.
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Affiliation(s)
- George Chung
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Ann M Rose
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Mark I R Petalcorin
- DNA Damage Response Laboratory, The Francis Crick Institute, South Mimms EN3 3LD, United Kingdom; Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN3 3LD, United Kingdom
| | - Julie S Martin
- DNA Damage Response Laboratory, The Francis Crick Institute, South Mimms EN3 3LD, United Kingdom; Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN3 3LD, United Kingdom
| | - Zebulin Kessler
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
| | - Luis Sanchez-Pulido
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Chris P Ponting
- Medical Research Council Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Judith L Yanowitz
- Magee-Womens Research Institute, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
| | - Simon J Boulton
- DNA Damage Response Laboratory, The Francis Crick Institute, South Mimms EN3 3LD, United Kingdom; Clare Hall Laboratories, The Francis Crick Institute, South Mimms EN3 3LD, United Kingdom
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38
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The effect of tributyltin chloride on Caenorhabditis elegans germline is mediated by a conserved DNA damage checkpoint pathway. Toxicol Lett 2014; 225:413-21. [DOI: 10.1016/j.toxlet.2014.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/03/2014] [Accepted: 01/07/2014] [Indexed: 11/22/2022]
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Buonanno M, Garty G, Grad M, Gendrel M, Hobert O, Brenner DJ. Microbeam irradiation of C. elegans nematode in microfluidic channels. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2013; 52:531-537. [PMID: 23942865 PMCID: PMC3809145 DOI: 10.1007/s00411-013-0485-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/18/2013] [Indexed: 06/02/2023]
Abstract
To perform high-throughput studies on the biological effects of ionizing radiation in vivo, we have implemented a microfluidic tool for microbeam irradiation of Caenorhabditis elegans. The device allows the immobilization of worms with minimal stress for a rapid and controlled microbeam irradiation of multiple samples in parallel. Adapted from an established design, our microfluidic clamp consists of 16 tapered channels with 10-μm-thin bottoms to ensure charged particle traversal. Worms are introduced into the microfluidic device through liquid flow between an inlet and an outlet, and the size of each microchannel guarantees that young adult worms are immobilized within minutes without the use of anesthesia. After site-specific irradiation with the microbeam, the worms can be released by reversing the flow direction in the clamp and collected for analysis of biological endpoints such as repair of radiation-induced DNA damage. For such studies, minimal sample manipulation and reduced use of drugs such as anesthetics that might interfere with normal physiological processes are preferable. By using our microfluidic device that allows simultaneous immobilization and imaging for irradiation of several whole living samples on a single clamp, here we show that 4.5-MeV proton microbeam irradiation induced DNA damage in wild-type C. elegans, as assessed by the formation of Rad51 foci that are essential for homologous repair of radiation-induced DNA damage.
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Affiliation(s)
- M Buonanno
- Radiological Research Accelerator Facility, Columbia University, 136 S. Broadway, P.O. Box 21, Irvington, NY, 10533, USA,
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40
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Wu X, Xu Y, Feng K, Tompkins JD, Her C. MutS homologue hMSH5: recombinational DSB repair and non-synonymous polymorphic variants. PLoS One 2013; 8:e73284. [PMID: 24023853 PMCID: PMC3762724 DOI: 10.1371/journal.pone.0073284] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/18/2013] [Indexed: 01/25/2023] Open
Abstract
Double-strand breaks (DSBs) constitute the most deleterious form of DNA lesions that can lead to genome alterations and cell death, and the vast majority of DSBs arise pathologically in response to DNA damaging agents such as ionizing radiation (IR) and chemotherapeutic agents. Recent studies have implicated a role for the human MutS homologue hMSH5 in homologous recombination (HR)-mediated DSB repair and the DNA damage response. In the present study, we show that hMSH5 promotes HR-based DSB repair, and this property resides in the carboxyl-terminal portion of the protein. Our results demonstrate that DSB-triggered hMSH5 chromatin association peaks at the proximal regions of the DSB and decreases gradually with increased distance from the break. Furthermore, the DSB-triggered hMSH5 chromatin association is preceded by and relies on the assembly of hMRE11 and hRad51 at the proximal regions of the DSB. Lastly, the potential effects of hMSH5 non-synonymous variants (L85F, Y202C, V206F, R351G, L377F, and P786S) on HR and cell survival in response to DSB-inducing anticancer agents have been analyzed. These experiments show that the expression of hMSH5 variants elicits different survival responses to anticancer drugs cisplatin, bleomycin, doxorubicin and camptothecin. However, the effects of hMSH5 variants on survival responses to DSB-inducing agents are not directly correlated to their effects exerted on HR-mediated DSB repair, suggesting that the roles of hMSH5 variants in the processes of DNA damage response and repair are multifaceted.
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Affiliation(s)
- Xiling Wu
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Yang Xu
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Katey Feng
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Joshua D. Tompkins
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - Chengtao Her
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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Saito TT, Lui DY, Kim HM, Meyer K, Colaiácovo MP. Interplay between structure-specific endonucleases for crossover control during Caenorhabditis elegans meiosis. PLoS Genet 2013; 9:e1003586. [PMID: 23874210 PMCID: PMC3715419 DOI: 10.1371/journal.pgen.1003586] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 05/07/2013] [Indexed: 11/18/2022] Open
Abstract
The number and distribution of crossover events are tightly regulated at prophase of meiosis I. The resolution of Holliday junctions by structure-specific endonucleases, including MUS-81, SLX-1, XPF-1 and GEN-1, is one of the main mechanisms proposed for crossover formation. However, how these nucleases coordinately resolve Holliday junctions is still unclear. Here we identify both the functional overlap and differences between these four nucleases regarding their roles in crossover formation and control in the Caenorhabditis elegans germline. We show that MUS-81, XPF-1 and SLX-1, but not GEN-1, can bind to HIM-18/SLX4, a key scaffold for nucleases. Analysis of synthetic mitotic defects revealed that MUS-81 and SLX-1, but not XPF-1 and GEN-1, have overlapping roles with the Bloom syndrome helicase ortholog, HIM-6, supporting their in vivo roles in processing recombination intermediates. Taking advantage of the ease of genetic analysis and high-resolution imaging afforded by C. elegans, we examined crossover designation, frequency, distribution and chromosomal morphology in single, double, triple and quadruple mutants of the structure-specific endonucleases. This revealed that XPF-1 functions redundantly with MUS-81 and SLX-1 in executing crossover formation during meiotic double-strand break repair. Analysis of crossover distribution revealed that SLX-1 is required for crossover suppression at the center region of the autosomes. Finally, analysis of chromosome morphology in oocytes at late meiosis I stages uncovered that SLX-1 and XPF-1 promote meiotic chromosomal stability by preventing formation of chromosomal abnormalities. We propose a model in which coordinate action between structure-specific nucleases at different chromosome domains, namely MUS-81, SLX-1 and XPF-1 at the arms and SLX-1 at the center region, exerts positive and negative regulatory roles, respectively, for crossover control during C. elegans meiosis.
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Affiliation(s)
- Takamune T. Saito
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Doris Y. Lui
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hyun-Min Kim
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Katherine Meyer
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Monica P. Colaiácovo
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
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Silva N, Adamo A, Santonicola P, Martinez-Perez E, La Volpe A. Pro-crossover factors regulate damage-dependent apoptosis in the Caenorhabditis elegans germ line. Cell Death Differ 2013; 20:1209-18. [PMID: 23832114 DOI: 10.1038/cdd.2013.68] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 05/17/2013] [Accepted: 05/20/2013] [Indexed: 12/20/2022] Open
Abstract
During meiosis, DNA double-strand breaks (DSBs) are physiologically induced to start the recombination process and promote the formation of interhomologue crossovers (COs), which are required to ensure faithful chromosome segregation into the gametes. The timely repair of DSBs is an essential part of the meiotic programme, as accumulation of unprocessed DSBs during the pachytene stage of meiotic prophase triggers a DNA damage checkpoint response that induces apoptosis of damaged cells. We show that CO-promoting factors MSH-4, MSH-5, and ZHP-3, but not COSA-1, are required for the apoptotic response of the meiotic DNA damage checkpoint. Lack of MSH-4 or MSH-5 suppresses the apoptotic response observed in some DNA repair-defective mutants such as fcd-2 and brc-1 (orthologues of FANCD2 and BRCA1), irrespectively of the amount of DSBs present in pachytene nuclei. Although ionizing radiation fails to induce apoptosis in msh-4/5-mutant backgrounds, it induces transcriptional activation of the apoptosis-activator egl-1, which is controlled by the Caenorhabditis elegans p53 orthologue CEP-1. This finding suggests that MSH-4/5 involvement in the apoptotic response occurs downstream or independently of damage sensing and checkpoint activation. This study establishes a role for pro-CO factors MSH-4/5 and ZHP-3 in the execution of apoptosis at late meiotic prophase following the accumulation of exogenous or endogenous DNA damage.
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Affiliation(s)
- N Silva
- CNR, Institute of Genetics and Biophysics, Adriano Buzzati-Traverso, Via Pietro Castellino 111, Napels 80131, Italy
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43
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Impaired resection of meiotic double-strand breaks channels repair to nonhomologous end joining in Caenorhabditis elegans. Mol Cell Biol 2013; 33:2732-47. [PMID: 23671188 DOI: 10.1128/mcb.00055-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Repair of double-strand DNA breaks (DSBs) by the homologous recombination (HR) pathway results in crossovers (COs) required for a successful first meiotic division. Mre11 is one member of the MRX/N (Mre11, Rad50, and Xrs2/Nbs1) complex required for meiotic DSB formation and for resection in Saccharomyces cerevisiae. In Caenorhabditis elegans, evidence for the MRX/N role in DSB resection is limited. We report the first separation-of-function allele, mre-11(iow1) in C. elegans, which is specifically defective in meiotic DSB resection but not in formation. The mre-11(iow1) mutants displayed chromosomal fragmentation and aggregation in late prophase I. Recombination intermediates and crossover formation was greatly reduced in mre-11(iow1) mutants. Irradiation-induced DSBs during meiosis failed to be repaired from early to middle prophase I in mre-11(iow1) mutants. In the absence of a functional HR, our data suggest that some DSBs in mre-11(iow1) mutants are repaired by the nonhomologous end joining (NHEJ) pathway, as removing NHEJ partially suppressed the meiotic defects shown by mre-11(iow1). In the absence of NHEJ and a functional MRX/N, meiotic DSBs are channeled to EXO-1-dependent HR repair. Overall, our analysis supports a role for MRE-11 in the resection of DSBs in middle meiotic prophase I and in blocking NHEJ.
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Woglar A, Daryabeigi A, Adamo A, Habacher C, Machacek T, La Volpe A, Jantsch V. Matefin/SUN-1 phosphorylation is part of a surveillance mechanism to coordinate chromosome synapsis and recombination with meiotic progression and chromosome movement. PLoS Genet 2013; 9:e1003335. [PMID: 23505384 PMCID: PMC3591285 DOI: 10.1371/journal.pgen.1003335] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 01/08/2013] [Indexed: 12/01/2022] Open
Abstract
Faithful chromosome segregation during meiosis I depends on the establishment of a crossover between homologous chromosomes. This requires induction of DNA double-strand breaks (DSBs), alignment of homologs, homolog association by synapsis, and repair of DSBs via homologous recombination. The success of these events requires coordination between chromosomal events and meiotic progression. The conserved SUN/KASH nuclear envelope bridge establishes transient linkages between chromosome ends and cytoskeletal forces during meiosis. In Caenorhabditis elegans, this bridge is essential for bringing homologs together and preventing nonhomologous synapsis. Chromosome movement takes place during synapsis and recombination. Concomitant with the onset of chromosome movement, SUN-1 clusters at chromosome ends associated with the nuclear envelope, and it is phosphorylated in a chk-2- and plk-2-dependent manner. Identification of all SUN-1 phosphomodifications at its nuclear N terminus allowed us to address their role in prophase I. Failures in recombination and synapsis led to persistent phosphorylations, which are required to elicit a delay in progression. Unfinished meiotic tasks elicited sustained recruitment of PLK-2 to chromosome ends in a SUN-1 phosphorylation-dependent manner that is required for continued chromosome movement and characteristic of a zygotene arrest. Furthermore, SUN-1 phosphorylation supported efficient synapsis. We propose that signals emanating from a failure to successfully finish meiotic tasks are integrated at the nuclear periphery to regulate chromosome end-led movement and meiotic progression. The single unsynapsed X chromosome in male meiosis is precluded from inducing a progression delay, and we found it was devoid of a population of phosphorylated SUN-1. This suggests that SUN-1 phosphorylation is critical to delaying meiosis in response to perturbed synapsis. SUN-1 may be an integral part of a checkpoint system to monitor establishment of the obligate crossover, inducible only in leptotene/zygotene. Unrepaired DSBs and unsynapsed chromosomes maintain this checkpoint, but a crossover intermediate is necessary to shut it down.
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Affiliation(s)
- Alexander Woglar
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Anahita Daryabeigi
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Adele Adamo
- CNR Institute of Genetics and Biophysics “A. Buzzati-Traverso,” Napoli, Italy
| | - Cornelia Habacher
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Thomas Machacek
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Adriana La Volpe
- CNR Institute of Genetics and Biophysics “A. Buzzati-Traverso,” Napoli, Italy
| | - Verena Jantsch
- Department of Chromosome Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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45
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La Volpe A, Barchi M. Meiotic double strand breaks repair in sexually reproducing eukaryotes: We are not all equal. Exp Cell Res 2012; 318:1333-9. [DOI: 10.1016/j.yexcr.2012.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 03/14/2012] [Accepted: 03/14/2012] [Indexed: 11/16/2022]
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Kurzbauer MT, Uanschou C, Chen D, Schlögelhofer P. The recombinases DMC1 and RAD51 are functionally and spatially separated during meiosis in Arabidopsis. THE PLANT CELL 2012; 24:2058-70. [PMID: 22589466 PMCID: PMC3442587 DOI: 10.1105/tpc.112.098459] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 04/18/2012] [Accepted: 04/27/2012] [Indexed: 05/18/2023]
Abstract
Meiosis ensures the reduction of the genome before the formation of generative cells and promotes the exchange of genetic information between homologous chromosomes by recombination. Essential for these events are programmed DNA double strand breaks (DSBs) providing single-stranded DNA overhangs after their processing. These overhangs, together with the RADiation sensitive51 (RAD51) and DMC1 Disrupted Meiotic cDNA1 (DMC1) recombinases, mediate the search for homologous sequences. Current models propose that the two ends flanking a meiotic DSB have different fates during DNA repair, but the molecular details remained elusive. Here we present evidence, obtained in the model plant Arabidopsis thaliana, that the two recombinases, RAD51 and DMC1, localize to opposite sides of a meiotic DSB. We further demonstrate that the ATR kinase is involved in regulating DMC1 deposition at meiotic DSB sites, and that its elimination allows DMC1-mediated meiotic DSB repair even in the absence of RAD51. DMC1's ability to promote interhomolog DSB repair is not a property of the protein itself but the consequence of an ASYNAPTIC1 (Hop1)-mediated impediment for intersister repair. Taken together, these results demonstrate that DMC1 functions independently and spatially separated from RAD51 during meiosis and that ATR is an integral part of the regular meiotic program.
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47
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Tompkins JD, Wu X, Her C. MutS homologue hMSH5: role in cisplatin-induced DNA damage response. Mol Cancer 2012; 11:10. [PMID: 22401567 PMCID: PMC3325843 DOI: 10.1186/1476-4598-11-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 03/08/2012] [Indexed: 11/10/2022] Open
Abstract
Background Cisplatin (cis-diamminedichloroplatinum (II), CDDP) and its analogues constitute an important class of anticancer drugs in the treatment of various malignancies; however, its effectiveness is frequently affected by mutations in genes involved in the repair and signaling of cisplatin-induced DNA damage. These observations necessitate a need for a better understanding of the molecular events governing cellular sensitivity to cisplatin. Results Here, we show that hMSH5 mediates sensitization to cisplatin-induced DNA damage in human cells. Our study indicates that hMSH5 undergoes cisplatin-elicited protein induction and tyrosine phosphorylation. Silencing of hMSH5 by RNAi or expression of hMSH5 phosphorylation-resistant mutant hMSH5Y742F elevates cisplatin-induced G2 arrest and renders cells susceptible to cisplatin toxicity at clinically relevant doses. In addition, our data show that cisplatin promotes hMSH5 chromatin association and hMSH5 deficiency increases cisplatin-triggered γ-H2AX foci. Consistent with a possible role for hMSH5 in recombinational repair of cisplatin-triggered double-strand breaks (DSBs), the formation of cisplatin-induced hMSH5 nuclear foci is hRad51-dependent. Conclusion Collectively, our current study has suggested a role for hMSH5 in the processing of cisplatin-induced DSBs, and silencing of hMSH5 may provide a new means to improve the therapeutic efficacy of cisplatin.
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Affiliation(s)
- Joshua D Tompkins
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Mail Drop 64-7520, Pullman, WA 99164, USA
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48
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Pradillo M, López E, Linacero R, Romero C, Cuñado N, Sánchez-Morán E, Santos JL. Together yes, but not coupled: new insights into the roles of RAD51 and DMC1 in plant meiotic recombination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:921-33. [PMID: 22066484 DOI: 10.1111/j.1365-313x.2011.04845.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The eukaryotic recombinases RAD51 and DMC1 are essential for DNA strand-exchange between homologous chromosomes during meiosis. RAD51 is also expressed during mitosis, and mediates homologous recombination (HR) between sister chromatids. It has been suggested that DMC1 might be involved in the switch from intersister chromatid recombination in somatic cells to interhomolog meiotic recombination. At meiosis, the Arabidopsis Atrad51 null mutant fails to synapse and has extensive chromosome fragmentation. The Atdmc1 null mutant is also asynaptic, but in this case chromosome fragmentation is absent. Thus in plants, AtDMC1 appears to be indispensable for interhomolog homologous recombination, whereas AtRAD51 seems to be more involved in intersister recombination. In this work, we have studied a new AtRAD51 knock-down mutant, Atrad51-2, which expresses only a small quantity of RAD51 protein. Atrad51-2 mutant plants are sterile and hypersensitive to DNA double-strand break induction, but their vegetative development is apparently normal. The meiotic phenotype of the mutant consists of partial synapsis, an elevated frequency of univalents, a low incidence of chromosome fragmentation and multivalent chromosome associations. Surprisingly, non-homologous chromosomes are involved in 51% of bivalents. The depletion of AtDMC1 in the Atrad51-2 background results in the loss of bivalents and in an increase of chromosome fragmentation. Our results suggest that a critical level of AtRAD51 is required to ensure the fidelity of HR during interchromosomal exchanges. Assuming the existence of asymmetrical DNA strand invasion during the initial steps of recombination, we have developed a working model in which the initial step of strand invasion is mediated by AtDMC1, with AtRAD51 required to check the fidelity of this process.
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MESH Headings
- Arabidopsis/drug effects
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis/radiation effects
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Chromosomes, Plant/genetics
- Chromosomes, Plant/metabolism
- Cisplatin/pharmacology
- DNA Breaks, Double-Stranded/radiation effects
- DNA, Plant/genetics
- DNA, Plant/metabolism
- Gamma Rays
- Gene Knockout Techniques
- Genetic Complementation Test
- Homologous Recombination
- Meiosis
- Metaphase
- Models, Genetic
- Phenotype
- Plants, Genetically Modified/drug effects
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Plants, Genetically Modified/radiation effects
- Rad51 Recombinase/genetics
- Rad51 Recombinase/metabolism
- Rec A Recombinases/genetics
- Rec A Recombinases/metabolism
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Affiliation(s)
- Mónica Pradillo
- Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, Madrid 28040, Spain.
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Transgene-mediated cosuppression and RNA interference enhance germ-line apoptosis in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2012; 109:3440-5. [PMID: 22331911 DOI: 10.1073/pnas.1107390109] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction of multiple copies of a germ-line-expressed gene elicits silencing of the corresponding endogenous gene during Caenorhabditis elegans oogenesis; this process is referred to as germ-line cosuppression. Transformed plasmids assemble into extrachromosomal arrays resembling extra minichromosomes with repetitive structures. Loss of the transgene extrachromosomal array leads to reversion of the silencing phenomenon. Cosuppression and RNAi depend upon some of the same genes. In the C. elegans germ line, about half the cells undergo a physiological programmed cell death that shares most genetic requirements with somatic apoptosis. In addition, apoptosis is stimulated by DNA damage and synaptic failure mediated through different apoptotic checkpoints. We found that both germ-line cosuppression and RNAi of germ-line-expressed genes enhance apoptosis during C. elegans oogenesis. In contrast, apoptosis is not enhanced by extrachromosomal arrays carrying genes not driven by germ-line-specific promoters that thus do not elicit transgene-mediated cosuppression/silencing. Similarly, introduction of doubled-stranded RNA that shares no homology with endogenous genes has no effect on apoptosis. "Silencing-induced apoptosis" is dependent upon sir-2.1 and cep-1 (the worm p53 ortholog), and is accompanied by a rise in RAD-51 foci, a marker for ongoing DNA repair, indicating induction of DNA double-strand breaks. This finding suggests that the DNA damage-response pathway is involved. RNAi and cosuppression have been postulated as defense mechanisms against genomic intruders. We speculate that the mechanism here described may trigger the elimination of germ cells that have undergone viral infection or transposon activation.
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Abstract
Mutations in the him-5 gene in Caenorhabditis elegans strongly reduce the frequency of crossovers on the X chromosome, with lesser effects on the autosomes. him-5 mutants also show a change in crossover distribution on both the X and autosomes. These phenotypes are accompanied by a delayed entry into pachytene and premature desynapsis of the X chromosome. The nondisjunction, progression defects and desynapsis can be rescued by an exogenous source of double strand breaks (DSBs), indicating that the role of HIM-5 is to promote the formation of meiotic DSBs. Molecular cloning of the gene shows that the inferred HIM-5 product is a highly basic protein of 252 amino acids with no clear orthologs in other species, including other Caenorhabditis species. Although him-5 mutants are defective in segregation of the X chromosome, HIM-5 protein localizes preferentially to the autosomes. The mutant phenotypes and localization of him-5 are similar but not identical to the results seen with xnd-1, although unlike xnd-1, him-5 has no apparent effect on the acetylation of histone H2A on lysine 5 (H2AacK5). The localization of HIM-5 to the autosomes depends on the activities of both xnd-1 and him-17 allowing us to begin to establish pathways for the control of crossover distribution and frequency.
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