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Lima JT, Ferreira JG. Mechanobiology of the nucleus during the G2-M transition. Nucleus 2024; 15:2330947. [PMID: 38533923 DOI: 10.1080/19491034.2024.2330947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/09/2024] [Indexed: 03/28/2024] Open
Abstract
Cellular behavior is continuously influenced by mechanical forces. These forces span the cytoskeleton and reach the nucleus, where they trigger mechanotransduction pathways that regulate downstream biochemical events. Therefore, the nucleus has emerged as a regulator of cellular response to mechanical stimuli. Cell cycle progression is regulated by cyclin-CDK complexes. Recent studies demonstrated these biochemical pathways are influenced by mechanical signals, highlighting the interdependence of cellular mechanics and cell cycle regulation. In particular, the transition from G2 to mitosis (G2-M) shows significant changes in nuclear structure and organization, ranging from nuclear pore complex (NPC) and nuclear lamina disassembly to chromosome condensation. The remodeling of these mechanically active nuclear components indicates that mitotic entry is particularly sensitive to forces. Here, we address how mechanical forces crosstalk with the nucleus to determine the timing and efficiency of the G2-M transition. Finally, we discuss how the deregulation of nuclear mechanics has consequences for mitosis.
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Affiliation(s)
- Joana T Lima
- Epithelial Polarity and Cell Division Laboratory, Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
- Departamento de Biomedicina, Unidade de Biologia Experimental, Faculdade de Medicina do Porto, Porto, Portugal
- Programa Doutoral em Biomedicina, Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Jorge G Ferreira
- Epithelial Polarity and Cell Division Laboratory, Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal
- Departamento de Biomedicina, Unidade de Biologia Experimental, Faculdade de Medicina do Porto, Porto, Portugal
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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. 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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3
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Holzapfel R, Prell A, Schumacher F, Perschin V, Friedmann Angeli JP, Kleuser B, Stigloher C, Fazeli G. Degradation of hexosylceramides is required for timely corpse clearance via formation of cargo-containing phagolysosomal vesicles. Eur J Cell Biol 2024; 103:151411. [PMID: 38582051 DOI: 10.1016/j.ejcb.2024.151411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/08/2024] Open
Abstract
Efficient degradation of phagocytic cargo in lysosomes is crucial to maintain cellular homeostasis and defending cells against pathogens. However, the mechanisms underlying the degradation and recycling of macromolecular cargo within the phagolysosome remain incompletely understood. We previously reported that the phagolysosome containing the corpse of the polar body in C. elegans tubulates into small vesicles to facilitate corpse clearance, a process that requires cargo protein degradation and amino acid export. Here we show that degradation of hexosylceramides by the prosaposin ortholog SPP-10 and glucosylceramidases is required for timely corpse clearance. We observed accumulation of membranous structures inside endolysosomes of spp-10-deficient worms, which are likely caused by increased hexosylceramide species. spp-10 deficiency also caused alteration of additional sphingolipid subclasses, like dihydroceramides, 2-OH-ceramides, and dihydrosphingomyelins. While corpse engulfment, initial breakdown of corpse membrane inside the phagolysosome and lumen acidification proceeded normally in spp-10-deficient worms, formation of the cargo-containing vesicles from the corpse phagolysosome was reduced, resulting in delayed cargo degradation and phagolysosome resolution. Thus, by combining ultrastructural studies and sphingolipidomic analysis with observing single phagolysosomes over time, we identified a role of prosaposin/SPP-10 in maintaining phagolysosomal structure, which promotes efficient resolution of phagocytic cargos.
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Affiliation(s)
- Rebecca Holzapfel
- Imaging Core Facility, Biocenter, University of Würzburg, Würzburg, Germany
| | - Agata Prell
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Fabian Schumacher
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany; Core-Facility BioSupraMol, Pharma-MS subunit, Freie Universität Berlin, Germany
| | - Veronika Perschin
- Imaging Core Facility, Biocenter, University of Würzburg, Würzburg, Germany
| | - José Pedro Friedmann Angeli
- Chair of Translational Cell Biology, Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany
| | - Burkhard Kleuser
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
| | | | - Gholamreza Fazeli
- Chair of Translational Cell Biology, Rudolf Virchow Center for Integrative and Translational Bioimaging, University of Würzburg, Würzburg, Germany.
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4
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Chen YZ, Zimyanin V, Redemann S. Loss of the mitochondrial protein SPD-3 elevates PLK-1 levels and dysregulates mitotic events. Life Sci Alliance 2023; 6:e202302011. [PMID: 37684042 PMCID: PMC10488725 DOI: 10.26508/lsa.202302011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
In metazoans, Polo-like kinase (PLK1) controls several mitotic events including nuclear envelope breakdown, centrosome maturation, spindle assembly and progression through mitosis. Here we show that a mutation in the mitochondria-localized protein SPD-3 affects mitotic events by inducing elevated levels of PLK-1 in early Caenorhabditis elegans embryos. SPD-3 mutant embryos contain abnormally positioned mitotic chromosomes, show a delay in anaphase onset and asymmetrically disassemble the nuclear lamina. We found that more PLK-1 accumulated on centrosomes, nuclear envelope, nucleoplasm, and chromatin before NEBD, suggesting that PLK-1 overexpression is responsible for some of the observed mitotic phenotypes. In agreement with this, the chromosome positioning defects of the spd-3(oj35) mutant could be rescued by reducing PLK-1 levels. Our data suggests that the mitochondrial SPD-3 protein affects chromosome positioning and nuclear envelope integrity by up-regulating the endogenous levels of PLK-1 during early embryogenesis in C. elegans This finding suggests a novel link between mitochondria and nuclear envelope dynamics and chromosome positioning by increasing the amount of a key mitotic regulator, PLK-1, providing a novel link between mitochondria and mitosis.
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Affiliation(s)
- Yu-Zen Chen
- https://ror.org/0153tk833 Center for Membrane and Cell Physiology, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Vitaly Zimyanin
- https://ror.org/0153tk833 Center for Membrane and Cell Physiology, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Stefanie Redemann
- https://ror.org/0153tk833 Center for Membrane and Cell Physiology, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Molecular Physiology and Biological Physics, School of Medicine, University of Virginia, Charlottesville, VA, USA
- https://ror.org/0153tk833 Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, VA, USA
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5
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Nkombo Nkoula S, Velez-Aguilera G, Ossareh-Nazari B, Van Hove L, Ayuso C, Legros V, Chevreux G, Thomas L, Seydoux G, Askjaer P, Pintard L. Mechanisms of nuclear pore complex disassembly by the mitotic Polo-like kinase 1 (PLK-1) in C. elegans embryos. SCIENCE ADVANCES 2023; 9:eadf7826. [PMID: 37467327 PMCID: PMC10355831 DOI: 10.1126/sciadv.adf7826] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/16/2023] [Indexed: 07/21/2023]
Abstract
The nuclear envelope, which protects and organizes the genome, is dismantled during mitosis. In the Caenorhabditis elegans zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the maternal and paternal genomes. Nuclear pore complex (NPC) disassembly is a decisive step of NEBD, essential for nuclear permeabilization. By combining live imaging, biochemistry, and phosphoproteomics, we show that NPC disassembly is a stepwise process that involves Polo-like kinase 1 (PLK-1)-dependent and -independent steps. PLK-1 targets multiple NPC subcomplexes, including the cytoplasmic filaments, central channel, and inner ring. PLK-1 is recruited to and phosphorylates intrinsically disordered regions (IDRs) of several multivalent linker nucleoporins. Notably, although the phosphosites are not conserved between human and C. elegans nucleoporins, they are located in IDRs in both species. Our results suggest that targeting IDRs of multivalent linker nucleoporins is an evolutionarily conserved driver of NPC disassembly during mitosis.
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Affiliation(s)
- Sylvia Nkombo Nkoula
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Griselda Velez-Aguilera
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Batool Ossareh-Nazari
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Lucie Van Hove
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
| | - Cristina Ayuso
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Véronique Legros
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Guillaume Chevreux
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
| | - Laura Thomas
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Géraldine Seydoux
- HHMI and Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, Seville, Spain
| | - Lionel Pintard
- Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France
- Programme Équipe Labellisée Ligue contre le Cancer, Paris, France
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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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Nkoula SN, Velez-Aguilera G, Ossareh-Nazari B, Hove LV, Ayuso C, Legros V, Chevreux G, Thomas L, Seydoux G, Askjaer P, Pintard L. Mechanisms of Nuclear Pore Complex disassembly by the mitotic Polo-Like Kinase 1 (PLK-1) in C. elegans embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.528438. [PMID: 36865292 PMCID: PMC9980100 DOI: 10.1101/2023.02.21.528438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The nuclear envelope, which protects and organizes the interphase genome, is dismantled during mitosis. In the C. elegans zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the parental genomes. During NEBD, Nuclear Pore Complex (NPC) disassembly is critical for rupturing the nuclear permeability barrier and removing the NPCs from the membranes near the centrosomes and between the juxtaposed pronuclei. By combining live imaging, biochemistry, and phosphoproteomics, we characterized NPC disassembly and unveiled the exact role of the mitotic kinase PLK-1 in this process. We show that PLK-1 disassembles the NPC by targeting multiple NPC sub-complexes, including the cytoplasmic filaments, the central channel, and the inner ring. Notably, PLK-1 is recruited to and phosphorylates intrinsically disordered regions of several multivalent linker nucleoporins, a mechanism that appears to be an evolutionarily conserved driver of NPC disassembly during mitosis. (149/150 words). One-Sentence Summary PLK-1 targets intrinsically disordered regions of multiple multivalent nucleoporins to dismantle the nuclear pore complexes in the C. elegans zygote.
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8
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Kim HJ, Liu C, Zhang L, Dernburg AF. MJL-1 is a nuclear envelope protein required for homologous chromosome pairing and regulation of synapsis during meiosis in C. elegans. SCIENCE ADVANCES 2023; 9:eadd1453. [PMID: 36753547 PMCID: PMC9908027 DOI: 10.1126/sciadv.add1453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Interactions between chromosomes and LINC (linker of nucleoskeleton and cytoskeleton) complexes in the nuclear envelope (NE) promote homolog pairing and synapsis during meiosis. By tethering chromosomes to cytoskeletal motors, these connections lead to processive chromosome movements along the NE. This activity is usually mediated by telomeres, but in the nematode Caenorhabditis elegans, special chromosome regions called "pairing centers" (PCs) have acquired this meiotic function. Here, we identify a previously uncharacterized meiosis-specific NE protein, MJL-1 (MAJIN-Like-1), that is essential for interactions between PCs and LINC complexes in C. elegans. Mutations in MJL-1 eliminate active chromosome movements during meiosis, resulting in nonhomologous synapsis and impaired homolog pairing. Fission yeast and mice also require NE proteins to connect chromosomes to LINC complexes. Extensive similarities in the molecular architecture of meiotic chromosome-NE attachments across eukaryotes suggest a common origin and/or functions of this architecture during meiosis.
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Affiliation(s)
- Hyung Jun Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Chenshu Liu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Liangyu Zhang
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - Abby F. Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720-3200, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
- Biological Sciences and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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9
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Martinez-Garcia M, Naharro PR, Skinner MW, Baran KA, Lascarez-Lagunas LI, Nadarajan S, Shin N, Silva-García CG, Saito TT, Beese-Sims S, Diaz-Pacheco BN, Berson E, Castañer AB, Pacheco S, Martinez-Perez E, Jordan PW, Colaiácovo MP. GRAS-1 is a novel regulator of early meiotic chromosome dynamics in C. elegans. PLoS Genet 2023; 19:e1010666. [PMID: 36809245 PMCID: PMC9983901 DOI: 10.1371/journal.pgen.1010666] [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: 10/27/2022] [Revised: 03/03/2023] [Accepted: 02/13/2023] [Indexed: 02/23/2023] Open
Abstract
Chromosome movements and licensing of synapsis must be tightly regulated during early meiosis to ensure accurate chromosome segregation and avoid aneuploidy, although how these steps are coordinated is not fully understood. Here we show that GRAS-1, the worm homolog of mammalian GRASP/Tamalin and CYTIP, coordinates early meiotic events with cytoskeletal forces outside the nucleus. GRAS-1 localizes close to the nuclear envelope (NE) in early prophase I and interacts with NE and cytoskeleton proteins. Delayed homologous chromosome pairing, synaptonemal complex (SC) assembly, and DNA double-strand break repair progression are partially rescued by the expression of human CYTIP in gras-1 mutants, supporting functional conservation. However, Tamalin, Cytip double knockout mice do not exhibit obvious fertility or meiotic defects, suggesting evolutionary differences between mammals. gras-1 mutants show accelerated chromosome movement during early prophase I, implicating GRAS-1 in regulating chromosome dynamics. GRAS-1-mediated regulation of chromosome movement is DHC-1-dependent, placing it acting within the LINC-controlled pathway, and depends on GRAS-1 phosphorylation at a C-terminal S/T cluster. We propose that GRAS-1 coordinates the early steps of homology search and licensing of SC assembly by regulating the pace of chromosome movement in early prophase I.
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Affiliation(s)
- Marina Martinez-Garcia
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pedro Robles Naharro
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marnie W Skinner
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Kerstin A Baran
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Laura I Lascarez-Lagunas
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Saravanapriah Nadarajan
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nara Shin
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carlos G Silva-García
- Department of Molecular Metabolism, Harvard T. H. Chan School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Takamune T Saito
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sara Beese-Sims
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brianna N Diaz-Pacheco
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Elizaveta Berson
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ana B Castañer
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarai Pacheco
- MRC London Institute of Medical Sciences, London, United Kingdom
| | | | - Philip W Jordan
- Biochemistry and Molecular Biology Department, John Hopkins University, Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America
| | - Monica P Colaiácovo
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
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10
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Zhang L, Stauffer WT, Wang JS, Wu F, Yu Z, Liu C, Kim HJ, Dernburg AF. Recruitment of Polo-like kinase couples synapsis to meiotic progression via inactivation of CHK-2. eLife 2023; 12:84492. [PMID: 36700544 PMCID: PMC9998088 DOI: 10.7554/elife.84492] [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: 10/26/2022] [Accepted: 01/25/2023] [Indexed: 01/27/2023] Open
Abstract
Meiotic chromosome segregation relies on synapsis and crossover (CO) recombination between homologous chromosomes. These processes require multiple steps that are coordinated by the meiotic cell cycle and monitored by surveillance mechanisms. In diverse species, failures in chromosome synapsis can trigger a cell cycle delay and/or lead to apoptosis. How this key step in 'homolog engagement' is sensed and transduced by meiotic cells is unknown. Here we report that in C. elegans, recruitment of the Polo-like kinase PLK-2 to the synaptonemal complex triggers phosphorylation and inactivation of CHK-2, an early meiotic kinase required for pairing, synapsis, and double-strand break (DSB) induction. Inactivation of CHK-2 terminates DSB formation and enables CO designation and cell cycle progression. These findings illuminate how meiotic cells ensure CO formation and accurate chromosome segregation.
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Affiliation(s)
- Liangyu Zhang
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Weston T Stauffer
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Department of Integrative Biology, University of California, BerkeleyBerkeleyUnited States
| | - John S Wang
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Fan Wu
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Zhouliang Yu
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
| | - Chenshu Liu
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
| | - Hyung Jun Kim
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Abby F Dernburg
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
- California Institute for Quantitative BiosciencesBerkeleyUnited States
- Howard Hughes Medical InstituteChevy ChaseUnited States
- Biological Systems and Engineering Division, Lawrence Berkeley National LaboratoryBerkeleyUnited States
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11
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Nuclear envelope assembly and dynamics during development. Semin Cell Dev Biol 2023; 133:96-106. [PMID: 35249812 DOI: 10.1016/j.semcdb.2022.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 01/22/2023]
Abstract
The nuclear envelope (NE) protects but also organizes the eukaryotic genome. In this review we will discuss recent literature on how the NE disassembles and reassembles, how it varies in surface area and protein composition and how this translates into chromatin organization and gene expression in the context of animal development.
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12
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Chen YZ, Zimyanin V, Redemann S. Mitotic events depend on regulation of PLK-1 levels by the mitochondrial protein SPD-3. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523633. [PMID: 36711457 PMCID: PMC9882028 DOI: 10.1101/2023.01.11.523633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In metazoans, Polo Kinase (Plk1) controls several mitotic events including nuclear envelope breakdown, centrosome maturation and kinetochore assembly. Here we show that mitotic events regulated by Polo Like Kinase (PLK-1) in early C. elegans embryos depend on the mitochondrial-localized protein SPD-3. spd-3 mutant one-cell embryos contain abnormally positioned mitotic chromosomes and prematurely and asymmetrically disassemble the nuclear lamina. Nuclear envelope breakdown (NEBD) in C. elegans requires direct dephosphorylation of lamin by PLK-1. In spd-3 mutants PLK-1 levels are ~6X higher in comparison to control embryos and PLK-1::GFP was highly accumulated at centrosomes, the nuclear envelope, nucleoplasm, and chromosomes prior to NEBD. Partial depletion of plk-1 in spd-3 mutant embryos rescued mitotic chromosome and spindle positioning defects indicating that these phenotypes result from higher PLK-1 levels and thus activity. Our data suggests that the mitochondrial SPD-3 protein controls NEBD and chromosome positioning by regulating the endogenous levels of PLK-1 during early embryogenesis in C. elegans . This finding suggests a novel link between mitochondria and mitotic events by controlling the amount of a key mitotic regulator, PLK-1 and thus may have further implications in the context of cancers or age-related diseases and infertility as it provides a novel link between mitochondria and mitosis.
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Affiliation(s)
- Yu-Zen Chen
- Center for Membrane and Cell Physiology, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
| | - Vitaly Zimyanin
- Center for Membrane and Cell Physiology, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
| | - Stefanie Redemann
- Center for Membrane and Cell Physiology, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia, School of Medicine, Charlottesville, VA, USA
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13
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Jain N, Lord JM, Vogel V. Mechanoimmunology: Are inflammatory epigenetic states of macrophages tuned by biophysical factors? APL Bioeng 2022; 6:031502. [PMID: 36051106 PMCID: PMC9427154 DOI: 10.1063/5.0087699] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 07/26/2022] [Indexed: 11/17/2022] Open
Abstract
Many inflammatory diseases that are responsible for a majority of deaths are still uncurable, in part as the underpinning pathomechanisms and how to combat them is still poorly understood. Tissue-resident macrophages play pivotal roles in the maintenance of tissue homeostasis, but if they gradually convert to proinflammatory phenotypes, or if blood-born proinflammatory macrophages persist long-term after activation, they contribute to chronic inflammation and fibrosis. While biochemical factors and how they regulate the inflammatory transcriptional response of macrophages have been at the forefront of research to identify targets for therapeutic interventions, evidence is increasing that physical factors also tune the macrophage phenotype. Recently, several mechanisms have emerged as to how physical factors impact the mechanobiology of macrophages, from the nuclear translocation of transcription factors to epigenetic modifications, perhaps even DNA methylation. Insight into the mechanobiology of macrophages and associated epigenetic modifications will deliver novel therapeutic options going forward, particularly in the context of increased inflammation with advancing age and age-related diseases. We review here how biophysical factors can co-regulate pro-inflammatory gene expression and epigenetic modifications and identify knowledge gaps that require urgent attention if this therapeutic potential is to be realized.
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Affiliation(s)
| | | | - Viola Vogel
- Department of Health Sciences and Technology, Institute of Translational Medicine, ETH Zurich, Zurich, Switzerland
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14
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Kim HJ, Liu C, Dernburg AF. How and Why Chromosomes Interact with the Cytoskeleton during Meiosis. Genes (Basel) 2022; 13:genes13050901. [PMID: 35627285 PMCID: PMC9140367 DOI: 10.3390/genes13050901] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/28/2022] Open
Abstract
During the early meiotic prophase, connections are established between chromosomes and cytoplasmic motors via a nuclear envelope bridge, known as a LINC (linker of nucleoskeleton and cytoskeleton) complex. These widely conserved links can promote both chromosome and nuclear motions. Studies in diverse organisms have illuminated the molecular architecture of these connections, but important questions remain regarding how they contribute to meiotic processes. Here, we summarize the current knowledge in the field, outline the challenges in studying these chromosome dynamics, and highlight distinctive features that have been characterized in major model systems.
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Affiliation(s)
- Hyung Jun Kim
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA;
| | - Chenshu Liu
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA;
| | - Abby F. Dernburg
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA;
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815-6789, USA;
- Correspondence:
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15
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Velez-Aguilera G, Ossareh-Nazari B, Van Hove L, Joly N, Pintard L. Cortical microtubule pulling forces contribute to the union of the parental genomes in the C. elegans zygote. eLife 2022; 11:75382. [PMID: 35259092 PMCID: PMC8956289 DOI: 10.7554/elife.75382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/04/2022] [Indexed: 11/23/2022] Open
Abstract
Previously, we reported that the Polo-like kinase PLK-1 phosphorylates the single Caenorhabditis elegans lamin (LMN-1) to trigger lamina depolymerization during mitosis. We showed that this event is required to form a pronuclear envelope scission event that removes membranes on the juxtaposed oocyte and sperm pronuclear envelopes in the zygote, allowing the parental chromosomes to merge in a single nucleus after segregation (Velez-Aguilera et al., 2020). Here, we show that cortical microtubule pulling forces contribute to pronuclear envelopes scission by promoting mitotic spindle elongation, and conversely, nuclear envelopes remodeling facilitates spindle elongation. We also demonstrate that weakening the pronuclear envelopes via PLK-1-mediated lamina depolymerization, is a prerequisite for the astral microtubule pulling forces to trigger pronuclear membranes scission. Finally, we provide evidence that PLK-1 mainly acts via lamina depolymerization in this process. These observations thus indicate that temporal coordination between lamina depolymerization and mitotic spindle elongation facilitates pronuclear envelopes scission and parental genomes unification.
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Affiliation(s)
| | | | - Lucie Van Hove
- Cell Cycle and Development, Institut Jacques Monod, Paris, France
| | - Nicolas Joly
- Cell Cycle and Development, Institut Jacques Monod, Paris, France
| | - Lionel Pintard
- Cell Cycle and Development, Institut Jacques Monod, Paris, France
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16
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Baudrimont A, Paouneskou D, Mohammad A, Lichtenberger R, Blundon J, Kim Y, Hartl M, Falk S, Schedl T, Jantsch V. Release of CHK-2 from PPM-1.D anchorage schedules meiotic entry. SCIENCE ADVANCES 2022; 8:eabl8861. [PMID: 35171669 PMCID: PMC8849337 DOI: 10.1126/sciadv.abl8861] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 12/22/2021] [Indexed: 05/13/2023]
Abstract
Transition from the stem/progenitor cell fate to meiosis is mediated by several redundant posttranscriptional regulatory pathways in Caenorhabditis elegans. Interfering with all three branches causes tumorous germ lines. SCFPROM-1 comprises one branch and mediates a scheduled degradation step at entry into meiosis. prom-1 mutants show defects in the timely initiation of meiotic prophase I events, resulting in high rates of embryonic lethality. Here, we identify the phosphatase PPM-1.D/Wip1 as crucial substrate for PROM-1. We report that PPM-1.D antagonizes CHK-2 kinase, a key regulator for meiotic prophase initiation, including DNA double-strand breaks, chromosome pairing, and synaptonemal complex formation. We propose that PPM-1.D controls the amount of active CHK-2 via both catalytic and noncatalytic activities; notably, noncatalytic regulation seems to be crucial at meiotic entry. PPM-1.D sequesters CHK-2 at the nuclear periphery, and programmed SCFPROM-1-mediated degradation of PPM-1.D liberates the kinase and promotes meiotic entry.
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Affiliation(s)
- Antoine Baudrimont
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Dimitra Paouneskou
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Ariz Mohammad
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Raffael Lichtenberger
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Joshua Blundon
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Yumi Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Markus Hartl
- Mass Spectrometry Facility, Max Perutz Labs, Vienna BioCenter, Vienna, Austria
| | - Sebastian Falk
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
| | - Tim Schedl
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Labs, University of Vienna, Vienna BioCenter, Vienna, Austria
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17
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Shankar R, Lettman MM, Whisler W, Frankel EB, Audhya A. The ESCRT machinery directs quality control over inner nuclear membrane architecture. Cell Rep 2022; 38:110263. [PMID: 35045304 PMCID: PMC8801257 DOI: 10.1016/j.celrep.2021.110263] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 11/21/2021] [Accepted: 12/21/2021] [Indexed: 11/20/2022] Open
Abstract
The late-acting endosomal sorting complex required for transport (ESCRT) machinery has been implicated in facilitating the resealing of the nuclear envelope (NE) after mitosis, enabling compartmentalization of the genome away from the cytoplasm. Here, we leverage the stereotypic first division of the C. elegans embryo to identify additional functions of the ESCRT machinery in maintaining the structure of the inner nuclear membrane. Specifically, impaired ESCRT function results in a defect in the pruning of inner nuclear membrane invaginations, which arise normally during NE reformation and expansion. Additionally, in combination with a hypomorphic mutation that interferes with assembly of the underlying nuclear lamina, inhibition of ESCRT function significantly perturbs NE architecture and increases chromosome segregation defects, resulting in penetrant embryonic lethality. Our findings highlight links between ESCRT-mediated inner nuclear membrane remodeling, maintenance of nuclear envelope morphology, and the preservation of the genome during early development. In this study, Shankar et al. demonstrate that defects in ESCRT machinery functions impair pruning of inner nuclear membrane invaginations that form normally after mitotic exit as the nuclear envelope undergoes expansion. These findings highlight a critical role for the ESCRT machinery in the maintenance of inner nuclear membrane morphology.
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Affiliation(s)
- Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Molly M Lettman
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - William Whisler
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Elisa B Frankel
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA.
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18
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Nozaki T, Chang F, Weiner B, Kleckner N. High Temporal Resolution 3D Live-Cell Imaging of Budding Yeast Meiosis Defines Discontinuous Actin/Telomere-Mediated Chromosome Motion, Correlated Nuclear Envelope Deformation and Actin Filament Dynamics. Front Cell Dev Biol 2021; 9:687132. [PMID: 34900979 PMCID: PMC8656277 DOI: 10.3389/fcell.2021.687132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022] Open
Abstract
Chromosome movement is prominent at mid-meiotic prophase and is proposed to enhance the efficiency and/or stringency of homolog pairing and/or to help prevent or resolve topological entanglements. Here, we combine fluorescent repressor operator system (FROS) labeling with three-dimensional (3D) live-cell imaging at high spatio-temporal resolution to define the detailed kinetics of mid-meiotic prophase motion for a single telomere-proximal locus in budding yeast. Telomere motions can be grouped into three general categories: (i) pauses, in which the telomere “jiggles in place”; (ii) rapid, straight/curvilinear motion which reflects Myo2/actin-mediated transport of the monitored telomere; and (iii) slower directional motions, most of which likely reflect indirectly promoted motion of the monitored telomere in coordination with actin-mediated motion of an unmarked telomere. These and other findings highlight the importance of dynamic assembly/disassembly of telomere/LINC/actin ensembles and also suggest important roles for nuclear envelope deformations promoted by actin-mediated telomere/LINC movement. The presented low-SNR (signal-to-noise ratio) imaging methodology provides opportunities for future exploration of homolog pairing and related phenomena.
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Affiliation(s)
- Tadasu Nozaki
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Frederick Chang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Beth Weiner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States
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19
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Mad1's ability to interact with Mad2 is essential to regulate and monitor meiotic synapsis in C. elegans. PLoS Genet 2021; 17:e1009598. [PMID: 34762652 PMCID: PMC8610272 DOI: 10.1371/journal.pgen.1009598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 11/23/2021] [Accepted: 10/11/2021] [Indexed: 11/19/2022] Open
Abstract
Meiotic homolog synapsis is essential to ensure accurate segregation of chromosomes during meiosis. In C. elegans, proper regulation of synapsis and a checkpoint that monitors synapsis relies on the spindle checkpoint components, Mad1 and Mad2, and Pairing Centers (PCs), cis-acting loci that interact with the nuclear envelope to mobilize chromosomes within the nucleus. Here, we test what specific functions of Mad1 and Mad2 are required to regulate and monitor synapsis. We find that a mutation that prevents Mad1's localization to the nuclear periphery abolishes the synapsis checkpoint but has no effect on Mad2's localization to the nuclear periphery or synapsis. By contrast, a mutation that prevents Mad1's interaction with Mad2 abolishes the synapsis checkpoint, delays synapsis and fails to localize Mad2 to the nuclear periphery. These data indicate that Mad1's primary role in regulating synapsis is through control of Mad2 and that Mad2 can bind other factors at the nuclear periphery. We also tested whether Mad2's ability to adopt a specific conformation associated with its activity during spindle checkpoint function is required for its role in meiosis. A mutation that prevents Mad2 from adopting its active conformer fails to localize to the nuclear periphery, abolishes the synapsis checkpoint and exhibits substantial defects in meiotic synapsis. Thus, Mad2, and its regulation by Mad1, is an important regulator of meiotic synapsis in C. elegans.
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20
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Charar C, Metsuyanim-Cohen S, Bar DZ. Lamin regulates the dietary restriction response via the mTOR pathway in Caenorhabditis elegans. J Cell Sci 2021; 134:272061. [PMID: 34383046 PMCID: PMC8445603 DOI: 10.1242/jcs.258428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/30/2021] [Indexed: 11/30/2022] Open
Abstract
Animals subjected to dietary restriction (DR) have reduced body size, low fecundity, slower development, lower fat content and longer life span. We identified lamin as a regulator of multiple dietary restriction phenotypes. Downregulation of lmn-1, the single Caenorhabditis elegans lamin gene, increased animal size and fat content specifically in DR animals. The LMN-1 protein acts in the mTOR pathway, upstream of RAPTOR and S6 kinase β1 (S6K), a key component of and target of the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1), respectively. DR excludes the mTORC1 activator RAGC-1 from the nucleus. Downregulation of lmn-1 restores RAGC-1 to the nucleus, a necessary step for the activation of the mTOR pathway. These findings further link lamin to metabolic regulation. Summary: Downregulation of the single C. elegans lamin gene increases animal size and fat content specifically in dietary restricted animals. The lamin protein acts in the mTOR pathway to regulate these phenotypes.
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Affiliation(s)
- Chayki Charar
- The School of Dental Medicine, The Faculty of Medicine, Tel Aviv University, Israel.,The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | | | - Daniel Z Bar
- The School of Dental Medicine, The Faculty of Medicine, Tel Aviv University, Israel
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21
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Dello Stritto MR, Bauer B, Barraud P, Jantsch V. DNA topoisomerase 3 is required for efficient germ cell quality control. J Cell Biol 2021; 220:211935. [PMID: 33798260 PMCID: PMC8025215 DOI: 10.1083/jcb.202012057] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/21/2021] [Accepted: 03/12/2021] [Indexed: 12/31/2022] Open
Abstract
An important quality control mechanism eliminates meiocytes that have experienced recombination failure during meiosis. The culling of defective oocytes in Caenorhabditis elegans meiosis resembles late oocyte elimination in female mammals. Here we show that topoisomerase 3 depletion generates DNA lesions in both germline mitotic and meiotic compartments that are less capable of triggering p53 (cep-1)–dependent apoptosis, despite the activation of DNA damage and apoptosis signaling. Elimination of nonhomologous, alternative end joining and single strand annealing repair factors (CKU-70, CKU-80, POLQ-1, and XPF-1) can alleviate the apoptosis block. Remarkably, the ability of single mutants in the other members of the Bloom helicase-topoisomerase-RMI1 complex to elicit apoptosis is not compromised, and depletion of Bloom helicase in topoisomerase 3 mutants restores an effective apoptotic response. Therefore, uncontrolled Bloom helicase activity seems to direct DNA repair toward normally not used repair pathways, and this counteracts efficient apoptosis. This implicates an as-yet undescribed requirement for topoisomerase 3 in mounting an effective apoptotic response to ensure germ cell quality control.
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Affiliation(s)
- Maria Rosaria Dello Stritto
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Bernd Bauer
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Pierre Barraud
- Expression Génétique Microbienne, UMR 8261, Centre Nationale de la Recherche Scientific, Université de Paris, Institut de Biologie Physico-Chimique, Paris, France
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
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22
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Brandt JN, Hussey KA, Kim Y. Spatial and temporal control of targeting Polo-like kinase during meiotic prophase. J Cell Biol 2021; 219:152136. [PMID: 32997737 PMCID: PMC7594494 DOI: 10.1083/jcb.202006094] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/19/2020] [Accepted: 08/28/2020] [Indexed: 12/17/2022] Open
Abstract
Polo-like kinases (PLKs) play widely conserved roles in orchestrating meiotic chromosome dynamics. However, how PLKs are targeted to distinct subcellular localizations during meiotic progression remains poorly understood. Here, we demonstrate that the cyclin-dependent kinase CDK-1 primes the recruitment of PLK-2 to the synaptonemal complex (SC) through phosphorylation of SYP-1 in C. elegans. SYP-1 phosphorylation by CDK-1 occurs just before meiotic onset. However, PLK-2 docking to the SC is prevented by the nucleoplasmic HAL-2/3 complex until crossover designation, which constrains PLK-2 to special chromosomal regions known as pairing centers to ensure proper homologue pairing and synapsis. PLK-2 is targeted to crossover sites primed by CDK-1 and spreads along the SC by reinforcing SYP-1 phosphorylation on one side of each crossover only when threshold levels of crossovers are generated. Thus, the integration of chromosome-autonomous signaling and a nucleus-wide crossover-counting mechanism partitions holocentric chromosomes relative to the crossover site, which ultimately defines the pattern of chromosome segregation during meiosis I.
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Affiliation(s)
- James N Brandt
- Department of Biology, Johns Hopkins University, Baltimore, MD
| | | | - Yumi Kim
- Department of Biology, Johns Hopkins University, Baltimore, MD
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23
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LINC complex regulation of genome organization and function. Curr Opin Genet Dev 2021; 67:130-141. [PMID: 33524904 DOI: 10.1016/j.gde.2020.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/25/2020] [Accepted: 12/11/2020] [Indexed: 12/28/2022]
Abstract
The regulation of genomic function is in part mediated through the physical organization and architecture of the nucleus. Disruption to nuclear organization and architecture is increasingly being recognized by its contribution to many diseases. The LINC complexes - protein structures traversing the nuclear envelope, that physically connect the nuclear interior, and hence the genome, to cytoplasmic cytoskeletal networks are an important component in the physical organization of the genome and its function. This connection, potentially allows for the constant detection of environmental mechanical stimuli, resulting in altered regulation of nuclear architecture and genome function, either directly or via the process of mechanotransduction. Here, we review the influences LINC complexes exert on genome functions and their impact on cellular/organismal health.
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24
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Charar C, Metsuyanim-Cohen S, Gruenbaum Y, Bar DZ. Exploring the nuclear lamina in health and pathology using C. elegans. Curr Top Dev Biol 2021; 144:91-110. [PMID: 33992162 DOI: 10.1016/bs.ctdb.2020.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The eukaryotic genome inside the nucleus is enveloped by two membranes, the Outer Nuclear Membrane (ONM) and the Inner Nuclear Membrane (INM). Tethered to the INM is the nuclear lamina, a fibrillar network composed of lamins-the nuclear intermediate filaments, and membrane associated proteins. The nuclear lamina interacts with several nuclear structures, including chromatin. As most nuclear functions, including regulation of gene expression, chromosome segregation and duplication as well as nuclear structure, are highly conserved in metazoans, the Caenorhabditis elegans nematode serves as a powerful model organism to study nuclear processes and architecture. This translucent organism can easily be observed under a microscope as a live embryo, larvae and even adult. Here we will review the data on nuclear lamina composition and functions gathered from studies using C. elegans model organisms: We will discuss genome spatial organization and its contribution to gene expression. We will review both the interaction between the cytoplasm and the nucleus and mechanotransduction mechanism. Finally, we will discuss disease causing mutation in nuclear lamins, including the use of this animal model in diseases research.
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Affiliation(s)
- Chayki Charar
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel; Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sally Metsuyanim-Cohen
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daniel Z Bar
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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25
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Velez-Aguilera G, Nkombo Nkoula S, Ossareh-Nazari B, Link J, Paouneskou D, Van Hove L, Joly N, Tavernier N, Verbavatz JM, Jantsch V, Pintard L. PLK-1 promotes the merger of the parental genome into a single nucleus by triggering lamina disassembly. eLife 2020; 9:59510. [PMID: 33030429 PMCID: PMC7544505 DOI: 10.7554/elife.59510] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022] Open
Abstract
Life of sexually reproducing organisms starts with the fusion of the haploid egg and sperm gametes to form the genome of a new diploid organism. Using the newly fertilized Caenorhabditis elegans zygote, we show that the mitotic Polo-like kinase PLK-1 phosphorylates the lamin LMN-1 to promote timely lamina disassembly and subsequent merging of the parental genomes into a single nucleus after mitosis. Expression of non-phosphorylatable versions of LMN-1, which affect lamina depolymerization during mitosis, is sufficient to prevent the mixing of the parental chromosomes into a single nucleus in daughter cells. Finally, we recapitulate lamina depolymerization by PLK-1 in vitro demonstrating that LMN-1 is a direct PLK-1 target. Our findings indicate that the timely removal of lamin is essential for the merging of parental chromosomes at the beginning of life in C. elegans and possibly also in humans, where a defect in this process might be fatal for embryo development.
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Affiliation(s)
- Griselda Velez-Aguilera
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Sylvia Nkombo Nkoula
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Batool Ossareh-Nazari
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Jana Link
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Dimitra Paouneskou
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Lucie Van Hove
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Nicolas Joly
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Nicolas Tavernier
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | | | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Lionel Pintard
- Programme Equipe Labéllisée Ligue Contre le Cancer - Team Cell Cycle & Development - Université de Paris, CNRS, Institut Jacques Monod, Paris, France
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Janisiw E, Raices M, Balmir F, Paulin LF, Baudrimont A, von Haeseler A, Yanowitz JL, Jantsch V, Silva N. Poly(ADP-ribose) glycohydrolase coordinates meiotic DNA double-strand break induction and repair independent of its catalytic activity. Nat Commun 2020; 11:4869. [PMID: 32978394 PMCID: PMC7519143 DOI: 10.1038/s41467-020-18693-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 09/07/2020] [Indexed: 02/07/2023] Open
Abstract
Poly(ADP-ribosyl)ation is a reversible post-translational modification synthetized by ADP-ribose transferases and removed by poly(ADP-ribose) glycohydrolase (PARG), which plays important roles in DNA damage repair. While well-studied in somatic tissues, much less is known about poly(ADP-ribosyl)ation in the germline, where DNA double-strand breaks are introduced by a regulated program and repaired by crossover recombination to establish a tether between homologous chromosomes. The interaction between the parental chromosomes is facilitated by meiotic specific adaptation of the chromosome axes and cohesins, and reinforced by the synaptonemal complex. Here, we uncover an unexpected role for PARG in coordinating the induction of meiotic DNA breaks and their homologous recombination-mediated repair in Caenorhabditis elegans. PARG-1/PARG interacts with both axial and central elements of the synaptonemal complex, REC-8/Rec8 and the MRN/X complex. PARG-1 shapes the recombination landscape and reinforces the tightly regulated control of crossover numbers without requiring its catalytic activity. We unravel roles in regulating meiosis, beyond its enzymatic activity in poly(ADP-ribose) catabolism. Poly(ADP-ribose) glycohydrolase (PARG) is involved in different cellular processes including DNA repair. Here the authors reveal a role for PARG in regulating meiotic DNA double strand break induction and repair in Caenorhabditis elegans.
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Affiliation(s)
- Eva Janisiw
- Department of Chromosome Biology, Max Perutz Laboratories, Vienna Biocenter, University of Vienna, Vienna, Austria.,Centre for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Marilina Raices
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Fabiola Balmir
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,AHN Center for Reproductive Medicine, AHN McCandless, Pittsburgh, PA, USA
| | - Luis F Paulin
- Center for Integrative Bioinformatics Vienna (CIBIV), Max Perutz Laboratories, Medical University of Vienna, Vienna BioCenter, University of Vienna, Vienna, Austria
| | - Antoine Baudrimont
- Department of Chromosome Biology, Max Perutz Laboratories, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Arndt von Haeseler
- Center for Integrative Bioinformatics Vienna (CIBIV), Max Perutz Laboratories, Medical University of Vienna, Vienna BioCenter, University of Vienna, Vienna, Austria.,Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Judith L Yanowitz
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, Vienna Biocenter, University of Vienna, Vienna, Austria
| | - Nicola Silva
- Department of Biology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.
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Abstract
Active meiotic chromosome movements are a universally conserved feature. They occur at the early stages of prophase of the first meiotic division and support the chromosome pairing process by (1) efficiently installing the synaptonemal complex between homologous chromosomes, (2) discouraging inadvertent chromosome interactions and (3) bringing homologous chromosomes into proximity. Chromosome movements are driven by forces in the cytoplasm, which are passed on to chromosome ends attached to the nuclear periphery by nuclear-membrane-spanning protein modules. In this extra view, we highlight our recent studies into the role of the nuclear lamina during this process to emphasize that it is a highly conserved structure in metazoans. The nuclear lamina forms a rigid proteinaceous network that underlies the inner nuclear membrane to provide stability to the nucleus. Misdemeanors of the nuclear lamina during meiosis has deleterious consequences for the viability and health of the offspring, highlighting the importance of a functional nuclear lamina during this cell cycle stage. Abbreviations: DSB: DNA double strand break; LEM: LAP2, Emerin, MAN1; LINC: LInker of the Nucleoskeleton and Cytoskeleton; RPM: rapid prophase movement; SUN/KASH: Sad1p, UNC-84/Klarsicht, ANC-1, Syne Homology
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Affiliation(s)
- Dimitra Paouneskou
- a Department of Chromosome Biology, Max F. Perutz Laboratories , University of Vienna , Vienna , Austria
| | - Verena Jantsch
- a Department of Chromosome Biology, Max F. Perutz Laboratories , University of Vienna , Vienna , Austria
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28
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"The nuclear envelope, a meiotic jack-of-all-trades". Curr Opin Cell Biol 2020; 64:34-42. [PMID: 32109733 DOI: 10.1016/j.ceb.2019.12.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/12/2019] [Accepted: 12/30/2019] [Indexed: 12/16/2022]
Abstract
The nucleus is one of the membrane-bound organelles that are a distinguishing feature between eukaryotes and prokaryotes. During meiosis, the nuclear envelope takes on functions beyond separating the nucleoplasm from the cytoplasm. These include associations with meiotic chromosomes to mediate pairing, being a sensor for recombination progression, and supportive of enormous nuclear growth during oocyte formation. In this review, we highlight recent results that have contributed to our understanding of meiotic nuclear envelope function and dynamics.
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Starr DA. A network of nuclear envelope proteins and cytoskeletal force generators mediates movements of and within nuclei throughout Caenorhabditis elegans development. Exp Biol Med (Maywood) 2019; 244:1323-1332. [PMID: 31495194 PMCID: PMC6880151 DOI: 10.1177/1535370219871965] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nuclear migration and anchorage, together referred to as nuclear positioning, are central to many cellular and developmental events. Nuclear positioning is mediated by a conserved network of nuclear envelope proteins that interacts with force generators in the cytoskeleton. At the heart of this network are li nker of n ucleoskeleton and c ytoskeleton (LINC) complexes made of S ad1 and UN C-84 (SUN) proteins at the inner nuclear membrane and K larsicht, A NC-1, and S yne homology (KASH) proteins in the outer nuclear membrane. LINC complexes span the nuclear envelope, maintain nuclear envelope architecture, designate the surface of nuclei distinctly from the contiguous endoplasmic reticulum, and were instrumental in the early evolution of eukaryotes. LINC complexes interact with lamins in the nucleus and with various cytoplasmic KASH effectors from the surface of nuclei. These effectors regulate the cytoskeleton, leading to a variety of cellular outputs including pronuclear migration, nuclear migration through constricted spaces, nuclear anchorage, centrosome attachment to nuclei, meiotic chromosome movements, and DNA damage repair. How LINC complexes are regulated and how they function are reviewed here. The focus is on recent studies elucidating the best-understood network of LINC complexes, those used throughout Caenorhabditis elegans development.
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Affiliation(s)
- Daniel A Starr
- Department of Molecular and Cellular Biology,
University of California, Davis, CA 95616, USA
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30
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Link J, Jantsch V. Meiotic chromosomes in motion: a perspective from Mus musculus and Caenorhabditis elegans. Chromosoma 2019; 128:317-330. [PMID: 30877366 PMCID: PMC6823321 DOI: 10.1007/s00412-019-00698-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 01/25/2023]
Abstract
Vigorous chromosome movement during the extended prophase of the first meiotic division is conserved in most eukaryotes. The movement is crucial for the faithful segregation of homologous chromosomes into daughter cells, and thus for fertility. A prerequisite for meiotic chromosome movement is the stable and functional attachment of telomeres or chromosome ends to the nuclear envelope and their cytoplasmic coupling to the cytoskeletal forces responsible for generating movement. Important advances in understanding the components, mechanisms, and regulation of chromosome end attachment and movement have recently been made. This review focuses on insights gained from experiments into two major metazoan model organisms: the mouse, Mus musculus, and the nematode, Caenorhabditis elegans.
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Affiliation(s)
- Jana Link
- Department of Chromosome Biology, Max F. Perutz Laboratories, Vienna Biocenter, University of Vienna, 1030, Vienna, Austria.
| | - Verena Jantsch
- Department of Chromosome Biology, Max F. Perutz Laboratories, Vienna Biocenter, University of Vienna, 1030, Vienna, Austria.
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31
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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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32
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Martinez-Garcia M, Schubert V, Osman K, Darbyshire A, Sanchez-Moran E, Franklin FCH. TOPII and chromosome movement help remove interlocks between entangled chromosomes during meiosis. J Cell Biol 2018; 217:4070-4079. [PMID: 30266762 PMCID: PMC6279386 DOI: 10.1083/jcb.201803019] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 08/04/2018] [Accepted: 09/19/2018] [Indexed: 02/07/2023] Open
Abstract
During meiosis, unrelated chromosomes frequently become interlocked, and these structures must be removed for complete synapsis and normal chromosome segregation. Martinez-Garcia et al. show that the active removal of interlocks requires topoisomerase II and chromosome movement. During the zygotene stage of meiosis, normal progression of chromosome synapsis and homologous recombination frequently lead to the formation of structural interlocks between entangled chromosomes. The persistence of interlocks through to the first meiotic division can jeopardize normal synapsis and occasionally chromosome segregation. However, they are generally removed by pachytene. It has been postulated that interlock removal requires one or more active processes, possibly involving topoisomerase II (TOPII) and/or chromosome movement. However, experimental evidence has been lacking. Analysis of a hypomorphic topII mutant and a meiosis-specific topII RNAi knockdown of Arabidopsis thaliana using immunocytochemistry and structured illumination microscopy (SIM) has now enabled us to demonstrate a role for TOPII in interlock resolution. Furthermore, analysis using a nucleoporin nup136 mutant, which affects chromosome movement, reveals that although TOPII activity is required for the removal of some interlock structures, for others, chromosome movement is also necessary. Thus, our study demonstrates that at least two mechanisms are required to ensure interlock removal.
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Affiliation(s)
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany
| | - Kim Osman
- School of Biosciences, University of Birmingham, Birmingham, UK
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Comparing and Contrasting the Effects of Drosophila Condensin II Subunit dCAP-D3 Overexpression and Depletion in Vivo. Genetics 2018; 210:531-546. [PMID: 30068527 PMCID: PMC6216582 DOI: 10.1534/genetics.118.301344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 07/31/2018] [Indexed: 11/18/2022] Open
Abstract
The Condensin II complex plays important, conserved roles in genome organization throughout the cell cycle and in the regulation of gene expression. Previous studies have linked decreased Condensin II subunit expression with a variety of diseases. Here, we show that elevated levels of Condensin II subunits are detected in somatic cancers. To evaluate potential biological effects of elevated Condensin II levels, we overexpressed the Condensin II subunit, dCAP-D3 in Drosophila melanogaster larval tissues and examined the effects on the mitotic- and interphase-specific functions of Condensin II. Interestingly, while ubiquitous overexpression resulted in pupal lethality, tissue specific overexpression of dCAP-D3 caused formation of nucleoplasmic protein aggregates which slowed mitotic prophase progression, mimicking results observed when dCAP-D3 levels are depleted. Surprisingly, dCAP-D3 aggregate formation resulted in faster transitions from metaphase to anaphase. Overexpressed dCAP-D3 protein failed to precipitate other Condensin II subunits in nondividing tissues, but did cause changes to gene expression which occurred in a manner opposite of what was observed when dCAP-D3 levels were depleted in both dividing and nondividing tissues. Our findings show that altering dCAP-D3 levels in either direction has detrimental effects on mitotic timing, the regulation of gene expression, and organism development. Taken together, these data suggest that the different roles for Condensin II throughout the cell cycle may be independent of each other and/or that dCAP-D3 may possess functions that are separate from those involving its association with the Condensin II complex. If conserved, these findings could have implications for tumors harboring elevated CAP-D3 levels.
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