1
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Narula JG, Wignall SM. Polo-like kinase 1 prevents excess microtubule polymerization in C. elegans oocytes to ensure faithful meiosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.03.606476. [PMID: 39131294 PMCID: PMC11312516 DOI: 10.1101/2024.08.03.606476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Sexual reproduction relies on meiosis, a specialized cell division program that produces haploid gametes. Oocytes of most organisms lack centrosomes, and therefore chromosome segregation is mediated by acentrosomal spindles. Here, we explore the role of Polo-like kinase 1 (PLK-1) in C. elegans oocytes, revealing mechanisms that ensure the fidelity of this unique form of cell division. Previously, PLK-1 was shown to be required for nuclear envelope breakdown and chromosome segregation in oocytes. We now find that PLK-1 is also required for establishing and maintaining acentrosomal spindle organization and for preventing excess microtubule polymerization in these cells. Additionally, our studies revealed an unexpected new role for this essential kinase. While PLK-1 is known to be required for centrosome maturation during mitosis, we found that removal of this kinase from oocytes caused premature recruitment of pericentriolar material to the sperm-provided centrioles following fertilization. Thus, PLK-1 suppresses centrosome maturation during oocyte meiosis, which is opposite to its role in mitosis. Taken together, our work reveals multiple new roles for PLK-1 in oocytes, identifying PLK-1 as a key player that promotes faithful acentrosomal meiosis.
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Affiliation(s)
- Juhi G Narula
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Sarah M Wignall
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
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2
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Camblor-Perujo S, Ozer Yildiz E, Küpper H, Overhoff M, Rastogi S, Bazzi H, Kononenko NL. The AP-2 complex interacts with γ-TuRC and regulates the proliferative capacity of neural progenitors. Life Sci Alliance 2024; 7:e202302029. [PMID: 38086550 PMCID: PMC10716017 DOI: 10.26508/lsa.202302029] [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: 03/07/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Centrosomes are organelles that nucleate microtubules via the activity of gamma-tubulin ring complexes (γ-TuRC). In the developing brain, centrosome integrity is central to the progression of the neural progenitor cell cycle, and its loss leads to microcephaly. We show that NPCs maintain centrosome integrity via the endocytic adaptor protein complex-2 (AP-2). NPCs lacking AP-2 exhibit defects in centrosome formation and mitotic progression, accompanied by DNA damage and accumulation of p53. This function of AP-2 in regulating the proliferative capacity of NPCs is independent of its role in clathrin-mediated endocytosis and is coupled to its association with the GCP2, GCP3, and GCP4 components of γ-TuRC. We find that AP-2 maintains γ-TuRC organization and regulates centrosome function at the level of MT nucleation. Taken together, our data reveal a novel, noncanonical function of AP-2 in regulating the proliferative capacity of NPCs and open new avenues for the identification of novel therapeutic strategies for the treatment of neurodevelopmental and neurodegenerative disorders with AP-2 complex dysfunction.
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Affiliation(s)
| | - Ebru Ozer Yildiz
- CECAD Excellence Center, University of Cologne, Cologne, Germany
| | - Hanna Küpper
- CECAD Excellence Center, University of Cologne, Cologne, Germany
| | - Melina Overhoff
- CECAD Excellence Center, University of Cologne, Cologne, Germany
- Center for Physiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Saumya Rastogi
- CECAD Excellence Center, University of Cologne, Cologne, Germany
| | - Hisham Bazzi
- CECAD Excellence Center, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Department of Dermatology and Venereology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Natalia L Kononenko
- CECAD Excellence Center, University of Cologne, Cologne, Germany
- Center for Physiology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
- Institute of Genetics, Natural Faculty, University of Cologne, Cologne, Germany
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3
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Zhu Z, Becam I, Tovey CA, Elfarkouchi A, Yen EC, Bernard F, Guichet A, Conduit PT. Multifaceted modes of γ-tubulin complex recruitment and microtubule nucleation at mitotic centrosomes. J Cell Biol 2023; 222:e202212043. [PMID: 37698931 PMCID: PMC10497398 DOI: 10.1083/jcb.202212043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 05/18/2023] [Accepted: 07/24/2023] [Indexed: 09/14/2023] Open
Abstract
Microtubule nucleation is mediated by γ-tubulin ring complexes (γ-TuRCs). In most eukaryotes, a GCP4/5/4/6 "core" complex promotes γ-tubulin small complex (γ-TuSC) association to generate cytosolic γ-TuRCs. Unlike γ-TuSCs, however, this core complex is non-essential in various species and absent from budding yeasts. In Drosophila, Spindle defective-2 (Spd-2) and Centrosomin (Cnn) redundantly recruit γ-tubulin complexes to mitotic centrosomes. Here, we show that Spd-2 recruits γ-TuRCs formed via the GCP4/5/4/6 core, but Cnn can recruit γ-TuSCs directly via its well-conserved CM1 domain, similar to its homologs in budding yeast. When centrosomes fail to recruit γ-tubulin complexes, they still nucleate microtubules via the TOG domain protein Mini-spindles (Msps), but these microtubules have different dynamic properties. Our data, therefore, help explain the dispensability of the GCP4/5/4/6 core and highlight the robustness of centrosomes as microtubule organizing centers. They also suggest that the dynamic properties of microtubules are influenced by how they are nucleated.
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Affiliation(s)
- Zihan Zhu
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Isabelle Becam
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Corinne A. Tovey
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Abir Elfarkouchi
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Eugenie C. Yen
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Fred Bernard
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Antoine Guichet
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Paul T. Conduit
- Department of Zoology, University of Cambridge, Cambridge, UK
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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4
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Kalbfuss N, Berger A, Gönczy P. Mapping of centriolar proteins onto the post-embryonic lineage of C. elegans. Dev Biol 2023; 502:68-76. [PMID: 37414202 DOI: 10.1016/j.ydbio.2023.07.001] [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: 04/25/2023] [Revised: 06/22/2023] [Accepted: 07/03/2023] [Indexed: 07/08/2023]
Abstract
Centrioles, together with the surrounding peri-centriolar material (PCM), constitute the centrosome, a major microtubule-organizing center of animal cells. Despite being critical in many cells for signaling, motility and division, centrioles can be eliminated in some systems, including in the vast majority of differentiating cells during embryogenesis in Caenorhabditis elegans. Whether the cells retaining centrioles in the resulting L1 larvae do so because they lack an activity that eliminates centrioles in the other cells is not known. Moreover, the extent to which centrioles and PCM remain present in later stages of worm development, when all cells but those of the germ line are terminally differentiated, is not known. Here, by fusing cells that lack centrioles with cells that retain them, we established that L1 larvae do not possess a diffusible elimination activity sufficient to remove centrioles. Moreover, analyzing PCM core proteins in L1 larval cells that retain centrioles, we found that some such proteins, but not all, are present as well. Furthermore, we uncovered that foci of centriolar proteins remain present in specific terminally differentiated cells of adult hermaphrodites and males, in particular in the somatic gonad. Correlating the time at which cells were born with the fate of their centrioles revealed that it is not cell age, but instead cell fate, that determines whether and when centrioles are eliminated. Overall, our work maps the localization of centriolar and PCM core proteins in the post-embryonic C. elegans lineage, thereby providing an essential blueprint for uncovering mechanisms modulating their presence and function.
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Affiliation(s)
- Nils Kalbfuss
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Antonin Berger
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, CH-1015, Switzerland
| | - Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, CH-1015, Switzerland.
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5
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Haruta N, Sumiyoshi E, Honda Y, Terasawa M, Uchiyama C, Toya M, Kubota Y, Sugimoto A. A germline-specific role for unconventional components of the γ-tubulin complex in Caenorhabditis elegans. J Cell Sci 2023; 136:jcs260922. [PMID: 37313686 PMCID: PMC10657210 DOI: 10.1242/jcs.260922] [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: 12/29/2022] [Accepted: 06/07/2023] [Indexed: 06/15/2023] Open
Abstract
The γ-tubulin complex (γTuC) is a widely conserved microtubule nucleator, but some of its components, namely GCP4, GCP5 and GCP6 (also known as TUBGCP4, TUBGCP5 and TUBGCP6, respectively), have not been detected in Caenorhabditis elegans. Here, we identified two γTuC-associated proteins in C. elegans, GTAP-1 and GTAP-2, for which apparent orthologs were detected only in the genus Caenorhabditis. GTAP-1 and GTAP-2 were found to localize at centrosomes and the plasma membrane of the germline, and their centrosomal localization was interdependent. In early C. elegans embryos, whereas the conserved γTuC component MZT-1 (also known as MOZART1 and MZT1) was essential for the localization of centrosomal γ-tubulin, depletion of GTAP-1 and/or GTAP-2 caused up to 50% reduction of centrosomal γ-tubulin and precocious disassembly of spindle poles during mitotic telophase. In the adult germline, GTAP-1 and GTAP-2 contributed to efficient recruitment of the γTuC to the plasma membrane. Depletion of GTAP-1, but not of GTAP-2, severely disrupted both the microtubule array and the honeycomb-like structure of the adult germline. We propose that GTAP-1 and GTAP-2 are unconventional components of the γTuC that contribute to the organization of both centrosomal and non-centrosomal microtubules by targeting the γTuC to specific subcellular sites in a tissue-specific manner.
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Affiliation(s)
- Nami Haruta
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Eisuke Sumiyoshi
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Yu Honda
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Masahiro Terasawa
- Laboratory for Developmental Genomics, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Chihiro Uchiyama
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Mika Toya
- Laboratory for Developmental Genomics, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
| | - Yukihiko Kubota
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
| | - Asako Sugimoto
- Laboratory of Developmental Dynamics, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
- Laboratory for Developmental Genomics, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan
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6
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Berman AY, Wieczorek M, Aher A, Olinares PDB, Chait BT, Kapoor TM. A nucleotide binding-independent role for γ-tubulin in microtubule capping and cell division. J Cell Biol 2023; 222:213828. [PMID: 36695784 PMCID: PMC9930161 DOI: 10.1083/jcb.202204102] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/20/2022] [Accepted: 12/22/2022] [Indexed: 01/26/2023] Open
Abstract
The γ-tubulin ring complex (γ-TuRC) has essential roles in centrosomal and non-centrosomal microtubule organization during vertebrate mitosis. While there have been important advances in understanding γ-TuRC-dependent microtubule nucleation, γ-TuRC capping of microtubule minus-ends remains poorly characterized. Here, we utilized biochemical reconstitutions and cellular assays to characterize the human γ-TuRC's capping activity. Single filament assays showed that the γ-TuRC remained associated with a nucleated microtubule for tens of minutes. In contrast, caps at dynamic microtubule minus-ends displayed lifetimes of ∼1 min. Reconstituted γ-TuRCs with nucleotide-binding deficient γ-tubulin (γ-tubulinΔGTP) formed ring-shaped complexes that did not nucleate microtubules but capped microtubule minus-ends with lifetimes similar to those measured for wild-type complexes. In dividing cells, microtubule regrowth assays revealed that while knockdown of γ-tubulin suppressed non-centrosomal microtubule formation, add-back of γ-tubulinΔGTP could substantially restore this process. Our results suggest that γ-TuRC capping is a nucleotide-binding-independent activity that plays a role in non-centrosomal microtubule organization during cell division.
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Affiliation(s)
- Adi Y. Berman
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA,Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY, USA
| | - Michal Wieczorek
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Amol Aher
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA
| | - Paul Dominic B. Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Brian T. Chait
- Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY, USA,Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, NY, USA
| | - Tarun M. Kapoor
- https://ror.org/0420db125Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY, USA,Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY, USA
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7
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Rothi MH, Greer EL. From correlation to causation: The new frontier of transgenerational epigenetic inheritance. Bioessays 2023; 45:e2200118. [PMID: 36351255 PMCID: PMC9772138 DOI: 10.1002/bies.202200118] [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: 06/16/2022] [Revised: 10/03/2022] [Accepted: 10/21/2022] [Indexed: 11/11/2022]
Abstract
While heredity is predominantly controlled by what deoxyribonucleic acid (DNA) sequences are passed from parents to their offspring, a small but growing number of traits have been shown to be regulated in part by the non-genetic inheritance of information. Transgenerational epigenetic inheritance is defined as heritable information passed from parents to their offspring without changing the DNA sequence. Work of the past seven decades has transitioned what was previously viewed as rare phenomenology, into well-established paradigms by which numerous traits can be modulated. For the most part, studies in model organisms have correlated transgenerational epigenetic inheritance phenotypes with changes in epigenetic modifications. The next steps for this field will entail transitioning from correlative studies to causal ones. Here, we delineate the major molecules that have been implicated in transgenerational epigenetic inheritance in both mammalian and non-mammalian models, speculate on additional molecules that could be involved, and highlight some of the tools which might help transition this field from correlation to causation.
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Affiliation(s)
- M. Hafiz Rothi
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston MA, USA
- Division of Newborn Medicine, Boston Children’s Hospital, Boston MA, USA
| | - Eric Lieberman Greer
- Department of Pediatrics, HMS Initiative for RNA Medicine, Harvard Medical School, Boston MA, USA
- Division of Newborn Medicine, Boston Children’s Hospital, Boston MA, USA
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8
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Woglar A, Pierron M, Schneider FZ, Jha K, Busso C, Gönczy P. Molecular architecture of the C. elegans centriole. PLoS Biol 2022; 20:e3001784. [PMID: 36107993 PMCID: PMC9531800 DOI: 10.1371/journal.pbio.3001784] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/04/2022] [Accepted: 08/04/2022] [Indexed: 11/19/2022] Open
Abstract
Uncovering organizing principles of organelle assembly is a fundamental pursuit in the life sciences. Caenorhabditis elegans was key in identifying evolutionary conserved components governing assembly of the centriole organelle. However, localizing these components with high precision has been hampered by the minute size of the worm centriole, thus impeding understanding of underlying assembly mechanisms. Here, we used Ultrastructure Expansion coupled with STimulated Emission Depletion (U-Ex-STED) microscopy, as well as electron microscopy (EM) and electron tomography (ET), to decipher the molecular architecture of the worm centriole. Achieving an effective lateral resolution of approximately 14 nm, we localize centriolar and PeriCentriolar Material (PCM) components in a comprehensive manner with utmost spatial precision. We found that all 12 components analysed exhibit a ring-like distribution with distinct diameters and often with a 9-fold radial symmetry. Moreover, we uncovered that the procentriole assembles at a location on the centriole margin where SPD-2 and ZYG-1 also accumulate. Moreover, SAS-6 and SAS-5 were found to be present in the nascent procentriole, with SAS-4 and microtubules recruited thereafter. We registered U-Ex-STED and EM data using the radial array of microtubules, thus allowing us to map each centriolar and PCM protein to a specific ultrastructural compartment. Importantly, we discovered that SAS-6 and SAS-4 exhibit a radial symmetry that is offset relative to microtubules, leading to a chiral centriole ensemble. Furthermore, we established that the centriole is surrounded by a region from which ribosomes are excluded and to which SAS-7 localizes. Overall, our work uncovers the molecular architecture of the C. elegans centriole in unprecedented detail and establishes a comprehensive framework for understanding mechanisms of organelle biogenesis and function.
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Affiliation(s)
- Alexander Woglar
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Marie Pierron
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Fabian Zacharias Schneider
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Keshav Jha
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Coralie Busso
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
| | - Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland
- * E-mail:
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9
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Shah P, Bao Z, Zaidel-Bar R. Visualizing and quantifying molecular and cellular processes in C. elegans using light microscopy. Genetics 2022; 221:6619563. [PMID: 35766819 DOI: 10.1093/genetics/iyac068] [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: 12/11/2021] [Accepted: 04/14/2022] [Indexed: 11/14/2022] Open
Abstract
Light microscopes are the cell and developmental biologists' "best friend", providing a means to see structures and follow dynamics from the protein to the organism level. A huge advantage of C. elegans as a model organism is its transparency, which coupled with its small size means that nearly every biological process can be observed and measured with the appropriate probe and light microscope. Continuous improvement in microscope technologies along with novel genome editing techniques to create transgenic probes have facilitated the development and implementation of a dizzying array of methods for imaging worm embryos, larvae and adults. In this review we provide an overview of the molecular and cellular processes that can be visualized in living worms using light microscopy. A partial inventory of fluorescent probes and techniques successfully used in worms to image the dynamics of cells, organelles, DNA, and protein localization and activity is followed by a practical guide to choosing between various imaging modalities, including widefield, confocal, lightsheet, and structured illumination microscopy. Finally, we discuss the available tools and approaches, including machine learning, for quantitative image analysis tasks, such as colocalization, segmentation, object tracking, and lineage tracing. Hopefully, this review will inspire worm researchers who have not yet imaged their worms to begin, and push those who are imaging to go faster, finer, and longer.
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Affiliation(s)
- Pavak Shah
- Department of Molecular, Cell, and Developmental Biology, University of California Los Angeles, Los Angeles 90095, USA
| | - Zhirong Bao
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065, USA
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
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10
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Lu YM, Zheng C. The Expression and Function of Tubulin Isotypes in Caenorhabditis elegans. Front Cell Dev Biol 2022; 10:860065. [PMID: 35399537 PMCID: PMC8987236 DOI: 10.3389/fcell.2022.860065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
Microtubules, made from the polymerization of the highly conserved α/β-tubulin heterodimers, serve as important components of the cytoskeleton in all eukaryotic cells. The existence of multiple tubulin isotypes in metazoan genomes and a dazzling variety of tubulin posttranslational modifications (PTMs) prompted the “tubulin code” hypothesis, which proposed that microtubule structure and functions are determined by the tubulin composition and PTMs. Evidence for the tubulin code has emerged from studies in several organisms with the characterization of specific tubulins for their expression and functions. The studies of tubulin PTMs are accelerated by the discovery of the enzymes that add or remove the PTMs. In tubulin research, the use of simple organisms, such as Caenorhabditis elegans, has been instrumental for understanding the expression and functional specialization of tubulin isotypes and the effects of their PTMs. In this review, we summarize the current understanding of the expression patterns and cellular functions of the nine α-tubulin and six β-tubulin isotypes. Expression studies are greatly facilitated by the CRISPR/Cas9-mediated endogenous GFP knock-in reporters and the organism-wide single cell transcriptomic studies. Meanwhile, functional studies benefit from the ease of genetic manipulation and precise gene replacement in C. elegans. These studies identified both ubiquitously expressed tubulin isotypes and tissue-specific isotypes. The isotypes showed functional redundancy, as well as functional specificity, which is likely caused by the subtle differences in their amino acid sequences. Many of these differences concentrate at the C-terminal tails that are subjected to several PTMs. Indeed, tubulin PTM, such as polyglutamylation, is shown to modulate microtubule organization and properties in both ciliated and non-ciliated neurons. Overall, studies from C. elegans support the distinct expression and function patterns of tubulin isotypes and the importance of their PTMs and offer the promise of cracking the tubulin code at the whole-genome and the whole-organism level.
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11
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McAlear TS, Bechstedt S. The mitotic spindle protein CKAP2 potently increases formation and stability of microtubules. eLife 2022; 11:72202. [PMID: 35029146 PMCID: PMC8798059 DOI: 10.7554/elife.72202] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 01/13/2022] [Indexed: 11/13/2022] Open
Abstract
Cells increase microtubule dynamics to make large rearrangements to their microtubule cytoskeleton during cell division. Changes in microtubule dynamics are essential for the formation and function of the mitotic spindle, and misregulation can lead to aneuploidy and cancer. Using in vitro reconstitution assays we show that the mitotic spindle protein Cytoskeleton-Associated Protein 2 (CKAP2) has a strong effect on nucleation of microtubules by lowering the critical tubulin concentration 100-fold. CKAP2 increases the apparent rate constant ka of microtubule growth by 50-fold and increases microtubule growth rates. In addition, CKAP2 strongly suppresses catastrophes. Our results identify CKAP2 as the most potent microtubule growth factor to date. These finding help explain CKAP2's role as an important spindle protein, proliferation marker, and oncogene.
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Affiliation(s)
- Thomas S McAlear
- Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
| | - Susanne Bechstedt
- Department of Anatomy and Cell Biology, McGill University, Montréal, Canada
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12
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Maheshwari R, Rahman MM, Joseph-Strauss D, Cohen-Fix O. An RNAi screen for genes that affect nuclear morphology in Caenorhabditis elegans reveals the involvement of unexpected processes. G3 (BETHESDA, MD.) 2021; 11:jkab264. [PMID: 34849797 PMCID: PMC8527477 DOI: 10.1093/g3journal/jkab264] [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: 06/30/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Aberration in nuclear morphology is one of the hallmarks of cellular transformation. However, the processes that, when mis-regulated, result aberrant nuclear morphology are poorly understood. In this study, we carried out a systematic, high-throughput RNAi screen for genes that affect nuclear morphology in Caenorhabditis elegans embryos. The screen employed over 1700 RNAi constructs against genes required for embryonic viability. Nuclei of early embryos are typically spherical, and their NPCs are evenly distributed. The screen was performed on early embryos expressing a fluorescently tagged component of the nuclear pore complex (NPC), allowing visualization of nuclear shape as well as the distribution of NPCs around the nuclear envelope. Our screen uncovered 182 genes whose downregulation resulted in one or more abnormal nuclear phenotypes, including multiple nuclei, micronuclei, abnormal nuclear shape, anaphase bridges, and abnormal NPC distribution. Many of these genes fall into common functional groups, including some that were not previously known to affect nuclear morphology, such as genes involved in mitochondrial function, the vacuolar ATPase, and the CCT chaperonin complex. The results of this screen add to our growing knowledge of processes that affect nuclear morphology and that may be altered in cancer cells that exhibit abnormal nuclear shape.
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Affiliation(s)
- Richa Maheshwari
- The Laboratory of Biochemistry and Genetics, The National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD 20892, USA
| | - Mohammad M Rahman
- The Laboratory of Biochemistry and Genetics, The National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD 20892, USA
| | - Daphna Joseph-Strauss
- The Laboratory of Biochemistry and Genetics, The National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD 20892, USA
| | - Orna Cohen-Fix
- The Laboratory of Biochemistry and Genetics, The National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD 20892, USA
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13
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Abstract
Centrioles are microtubule-based cylindrical structures that assemble the centrosome and template the formation of cilia. The proximal part of centrioles is associated with the pericentriolar material, a protein scaffold from which microtubules are nucleated. This activity is mediated by the γ-tubulin ring complex (γTuRC) whose central role in centrosomal microtubule organization has been recognized for decades. However, accumulating evidence suggests that γTuRC activity at this organelle is neither restricted to the pericentriolar material nor limited to microtubule nucleation. Instead, γTuRC is found along the entire centriole cylinder, at subdistal appendages, and inside the centriole lumen, where its canonical function as a microtubule nucleator might be supplemented or replaced by a function in microtubule anchoring and centriole stabilization, respectively. In this Opinion, we discuss recent insights into the expanded repertoire of γTuRC activities at centrioles and how distinct subpopulations of γTuRC might act in concert to ensure centrosome and cilia biogenesis and function, ultimately supporting cell proliferation, differentiation and homeostasis. We propose that the classical view of centrosomal γTuRC as a pericentriolar material-associated microtubule nucleator needs to be revised.
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Affiliation(s)
- Nina Schweizer
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Jens Lüders
- Mechanisms of Disease Programme, Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 10, 08028 Barcelona, Spain
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14
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Ohi R, Strothman C, Zanic M. Impact of the 'tubulin economy' on the formation and function of the microtubule cytoskeleton. Curr Opin Cell Biol 2021; 68:81-89. [PMID: 33160109 PMCID: PMC7925340 DOI: 10.1016/j.ceb.2020.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/19/2022]
Abstract
The microtubule cytoskeleton is assembled from a finite pool of α,β-tubulin, the size of which is controlled by an autoregulation mechanism. Cells also tightly regulate the architecture and dynamic behavior of microtubule arrays. Here, we discuss progress in our understanding of how tubulin autoregulation is achieved and highlight work showing that tubulin, in its unassembled state, is relevant for regulating the formation and organization of microtubules. Emerging evidence suggests that tubulin regulates microtubule-associated proteins and kinesin motors that are critical for microtubule nucleation, dynamics, and function. These relationships create feedback loops that connect the tubulin assembly cycle to the organization and dynamics of microtubule networks. We term this concept the 'tubulin economy', which emphasizes the idea that tubulin is a resource that can be deployed for the immediate purpose of creating polymers, or alternatively as a signaling molecule that has more far-reaching consequences for the organization of microtubule arrays.
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Affiliation(s)
- Ryoma Ohi
- Department of Cell and Developmental Biology, University of Michigan, USA.
| | - Claire Strothman
- Department of Cell and Developmental Biology, Vanderbilt University, USA
| | - Marija Zanic
- Department of Cell and Developmental Biology, Vanderbilt University, USA; Department of Biomolecular and Chemical Engineering, Department of Biochemistry, Vanderbilt University, USA.
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15
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Jaiswal S, Kasera H, Jain S, Khandelwal S, Singh P. Centrosome: A Microtubule Nucleating Cellular Machinery. J Indian Inst Sci 2021. [DOI: 10.1007/s41745-020-00213-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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16
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Wiegand T, Hyman AA. Drops and fibers - how biomolecular condensates and cytoskeletal filaments influence each other. Emerg Top Life Sci 2020; 4:247-261. [PMID: 33048111 PMCID: PMC7733666 DOI: 10.1042/etls20190174] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 12/13/2022]
Abstract
The cellular cytoskeleton self-organizes by specific monomer-monomer interactions resulting in the polymerization of filaments. While we have long thought about the role of polymerization in cytoskeleton formation, we have only begun to consider the role of condensation in cytoskeletal organization. In this review, we highlight how the interplay between polymerization and condensation leads to the formation of the cytoskeleton.
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Affiliation(s)
- Tina Wiegand
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
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17
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Aljohani MD, El Mouridi S, Priyadarshini M, Vargas-Velazquez AM, Frøkjær-Jensen C. Engineering rules that minimize germline silencing of transgenes in simple extrachromosomal arrays in C. elegans. Nat Commun 2020; 11:6300. [PMID: 33298957 PMCID: PMC7725773 DOI: 10.1038/s41467-020-19898-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/05/2020] [Indexed: 12/29/2022] Open
Abstract
Transgenes are prone to progressive silencing due to their structure, copy number, and genomic location. In C. elegans, repressive mechanisms are particularly strong in the germline with almost fully penetrant transgene silencing in simple extrachromosomal arrays and frequent silencing of single-copy transgene insertions. A class of non-coding DNA, Periodic An/Tn Clusters (PATCs) can prevent transgene-silencing in repressive chromatin or from small interfering RNAs (piRNAs). Here, we describe design rules (codon-optimization, intron and PATC inclusion, elevated temperature (25 °C), and vector backbone removal) for efficient germline expression from arrays in wildtype animals. We generate web-based tools to analyze PATCs and reagents for the convenient assembly of PATC-rich transgenes. An extensive collection of silencing resistant fluorescent proteins (e.g., gfp, mCherry, and tagBFP) can be used for dissecting germline regulatory elements and a set of enhanced enzymes (Mos1 transposase, Cas9, Cre, and Flp recombinases) enable efficient genetic engineering in C. elegans.
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Affiliation(s)
- Mohammed D Aljohani
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Sonia El Mouridi
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Monika Priyadarshini
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Amhed M Vargas-Velazquez
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal, 23955-6900, Saudi Arabia.
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18
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Gordon KL, Zussman JW, Li X, Miller C, Sherwood DR. Stem cell niche exit in C. elegans via orientation and segregation of daughter cells by a cryptic cell outside the niche. eLife 2020; 9:e56383. [PMID: 32692313 PMCID: PMC7467730 DOI: 10.7554/elife.56383] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/17/2020] [Indexed: 12/17/2022] Open
Abstract
Stem cells reside in and rely upon their niche to maintain stemness but must balance self-renewal with the production of daughters that leave the niche to differentiate. We discovered a mechanism of stem cell niche exit in the canonical C. elegans distal tip cell (DTC) germ stem cell niche mediated by previously unobserved, thin, membranous protrusions of the adjacent somatic gonad cell pair (Sh1). A disproportionate number of germ cell divisions were observed at the DTC-Sh1 interface. Stem-like and differentiating cell fates segregated across this boundary. Spindles polarized, pairs of daughter cells oriented between the DTC and Sh1, and Sh1 grew over the Sh1-facing daughter. Impeding Sh1 growth by RNAi to cofilin and Arp2/3 perturbed the DTC-Sh1 interface, reduced germ cell proliferation, and shifted a differentiation marker. Because Sh1 membrane protrusions eluded detection for decades, it is possible that similar structures actively regulate niche exit in other systems.
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Affiliation(s)
- Kacy L Gordon
- Department of Biology, The University of North Carolina at Chapel HillChapel HillUnited States
| | - Jay W Zussman
- Department of Biology, Duke UniversityDurhamUnited States
| | - Xin Li
- Department of Biology, The University of North Carolina at Chapel HillChapel HillUnited States
| | - Camille Miller
- Department of Biology, The University of North Carolina at Chapel HillChapel HillUnited States
| | - David R Sherwood
- Department of Biology, Duke UniversityDurhamUnited States
- Regeneration Next, Duke UniversityDurhamUnited States
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19
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Centrosome Aurora A gradient ensures single polarity axis in C. elegans embryos. Biochem Soc Trans 2020; 48:1243-1253. [PMID: 32597472 DOI: 10.1042/bst20200298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/25/2020] [Accepted: 06/08/2020] [Indexed: 01/31/2023]
Abstract
Cellular asymmetries are vital for generating cell fate diversity during development and in stem cells. In the newly fertilized Caenorhabditis elegans embryo, centrosomes are responsible for polarity establishment, i.e. anterior-posterior body axis formation. The signal for polarity originates from the centrosomes and is transmitted to the cell cortex, where it disassembles the actomyosin network. This event leads to symmetry breaking and the establishment of distinct domains of evolutionarily conserved PAR proteins. However, the identity of an essential component that localizes to the centrosomes and promotes symmetry breaking was unknown. Recent work has uncovered that the loss of Aurora A kinase (AIR-1 in C. elegans and hereafter referred to as Aurora A) in the one-cell embryo disrupts stereotypical actomyosin-based cortical flows that occur at the time of polarity establishment. This misregulation of actomyosin flow dynamics results in the occurrence of two polarity axes. Notably, the role of Aurora A in ensuring a single polarity axis is independent of its well-established function in centrosome maturation. The mechanism by which Aurora A directs symmetry breaking is likely through direct regulation of Rho-dependent contractility. In this mini-review, we will discuss the unconventional role of Aurora A kinase in polarity establishment in C. elegans embryos and propose a refined model of centrosome-dependent symmetry breaking.
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20
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Zheng Y, Buchwalter RA, Zheng C, Wight EM, Chen JV, Megraw TL. A perinuclear microtubule-organizing centre controls nuclear positioning and basement membrane secretion. Nat Cell Biol 2020; 22:297-309. [PMID: 32066907 PMCID: PMC7161059 DOI: 10.1038/s41556-020-0470-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 01/17/2020] [Indexed: 12/22/2022]
Abstract
Non-centrosomal microtubule-organizing centres (ncMTOCs) have a variety of roles presumed to serve the diverse functions of the range of cell types in which they are found. ncMTOCs are diverse in their composition, subcellular localization, and function. Here we report a perinuclear MTOC in Drosophila fat body cells that is anchored by Msp300/Nesprin at the cytoplasmic surface of the nucleus. Msp300 recruits the MT minus-end protein Patronin/CAMSAP, which functions redundantly with Ninein to further recruit the MT polymerase Msps/XMAP215 to assemble non-centrosomal MTs and does so independently of the widespread MT nucleation factor γ-tubulin. Functionally, the fat body ncMTOC and the radial MT arrays it organizes is essential for nuclear positioning and for secretion of basement membrane components via retrograde dynein-dependent endosomal trafficking that restricts plasma membrane growth. Together, this study identifies a perinuclear ncMTOC with unique architecture and MT regulation properties that serves vital functions.
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Affiliation(s)
- Yiming Zheng
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA.
| | - Rebecca A Buchwalter
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Chunfeng Zheng
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Elise M Wight
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Jieyan V Chen
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA.,Neuroscience Research Institute, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA.
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21
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Baumgart J, Kirchner M, Redemann S, Bond A, Woodruff J, Verbavatz JM, Jülicher F, Müller-Reichert T, Hyman AA, Brugués J. Soluble tubulin is significantly enriched at mitotic centrosomes. J Cell Biol 2019; 218:3977-3985. [PMID: 31636117 PMCID: PMC6891098 DOI: 10.1083/jcb.201902069] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/21/2019] [Accepted: 09/17/2019] [Indexed: 12/01/2022] Open
Abstract
Baumgart et al. measure the amount of dimeric and polymeric tubulin at mitotic centrosomes in C. elegans by light and electron microscopy. Centrosomes concentrate soluble tubulin tenfold over the cytoplasm, suggesting that centrosomal microtubule nucleation may be driven in part by concentrating tubulin. During mitosis, the centrosome expands its capacity to nucleate microtubules. Understanding the mechanisms of centrosomal microtubule nucleation is, however, constrained by a lack of knowledge of the amount of soluble and polymeric tubulin at mitotic centrosomes. Here we combined light microscopy and serial-section electron tomography to measure the amount of dimeric and polymeric tubulin at mitotic centrosomes in early C. elegans embryos. We show that a C. elegans one-cell stage centrosome at metaphase contains >10,000 microtubules with a total polymer concentration of 230 µM. Centrosomes concentrate soluble α/β tubulin by about 10-fold over the cytoplasm, reaching peak values of 470 µM, giving a combined total monomer and polymer tubulin concentration at centrosomes of up to 660 µM. These findings support in vitro data suggesting that microtubule nucleation in C. elegans centrosomes is driven in part by concentrating soluble tubulin.
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Affiliation(s)
- Johannes Baumgart
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Marcel Kirchner
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Stefanie Redemann
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.,Center for Membrane and Cell Physiology and Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA
| | - Alec Bond
- Department of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jeffrey Woodruff
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Department of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jean-Marc Verbavatz
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Centre for Systems Biology Dresden, Dresden, Germany.,Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Jan Brugués
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany .,Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Centre for Systems Biology Dresden, Dresden, Germany.,Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
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22
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Nance J, Frøkjær-Jensen C. The Caenorhabditis elegans Transgenic Toolbox. Genetics 2019; 212:959-990. [PMID: 31405997 PMCID: PMC6707460 DOI: 10.1534/genetics.119.301506] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/01/2019] [Indexed: 12/30/2022] Open
Abstract
The power of any genetic model organism is derived, in part, from the ease with which gene expression can be manipulated. The short generation time and invariant developmental lineage have made Caenorhabditis elegans very useful for understanding, e.g., developmental programs, basic cell biology, neurobiology, and aging. Over the last decade, the C. elegans transgenic toolbox has expanded considerably, with the addition of a variety of methods to control expression and modify genes with unprecedented resolution. Here, we provide a comprehensive overview of transgenic methods in C. elegans, with an emphasis on recent advances in transposon-mediated transgenesis, CRISPR/Cas9 gene editing, conditional gene and protein inactivation, and bipartite systems for temporal and spatial control of expression.
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Affiliation(s)
- Jeremy Nance
- Helen L. and Martin S. Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, New York 10016
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Science and Engineering Division (BESE), KAUST Environmental Epigenetics Program (KEEP), Thuwal 23955-6900, Saudi Arabia
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23
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Abstract
Microtubules are major constituents of the cytoskeleton in all eukaryotic cells. They are essential for chromosome segregation during cell division, for directional intracellular transport and for building specialized cellular structures such as cilia or flagella. Their assembly has to be controlled spatially and temporally. For this, the cell uses multiprotein complexes containing γ-tubulin. γ-Tubulin has been found in two different types of complexes, γ-tubulin small complexes and γ-tubulin ring complexes. Binding to adaptors and activator proteins transforms these complexes into structural templates that drive the nucleation of new microtubules in a highly controlled manner. This review discusses recent advances on the mechanisms of assembly, recruitment and activation of γ-tubulin complexes at microtubule-organizing centres.
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Affiliation(s)
- Dorian Farache
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Laurent Emorine
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Laurence Haren
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
| | - Andreas Merdes
- Centre de Biologie Intégrative, Centre de Biologie du Développement, CNRS-Université Toulouse III, 31062 Toulouse, France
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24
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Artiles KL, Fire AZ, Frøkjær-Jensen C. Assessment and Maintenance of Unigametic Germline Inheritance for C. elegans. Dev Cell 2019; 48:827-839.e9. [PMID: 30799227 PMCID: PMC6435406 DOI: 10.1016/j.devcel.2019.01.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 11/06/2018] [Accepted: 01/21/2019] [Indexed: 12/22/2022]
Abstract
The recent work of Besseling and Bringmann (2016) identified a molecular intervention for C. elegans in which premature segregation of maternal and paternal chromosomes in the fertilized oocyte can produce viable animals exhibiting a non-Mendelian inheritance pattern. Overexpression in embryos of a single protein regulating chromosome segregation (GPR-1) provides a germline derived clonally from a single parental gamete. We present a collection of strains and cytological assays to consistently generate and track non-Mendelian inheritance. These tools allow reproducible and high-frequency (>80%) production of non-Mendelian inheritance, the facile and simultaneous homozygosis for all nuclear chromosomes in a single generation, the precise exchange of nuclear and mitochondrial genomes between strains, and the assessments of non-canonical mitosis events. We show the utility of these strains by demonstrating a rapid assessment of cell lineage requirements (AB versus P1) for a set of genes (lin-2, lin-3, lin-12, and lin-31) with roles in C. elegans vulval development.
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Affiliation(s)
- Karen L Artiles
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew Z Fire
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Christian Frøkjær-Jensen
- King Abdullah University of Science and Technology, Biological and Environmental Science and Engineering Division, KAUST Environmental Epigenetics Program, Thuwal 23955-6900, Saudi Arabia.
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25
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γ-Tubulin small complex formation is essential for early zebrafish embryogenesis. Mech Dev 2018; 154:145-152. [DOI: 10.1016/j.mod.2018.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 01/01/2023]
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26
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Assembly of Mitotic Structures through Phase Separation. J Mol Biol 2018; 430:4762-4772. [DOI: 10.1016/j.jmb.2018.04.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/21/2018] [Accepted: 04/30/2018] [Indexed: 01/01/2023]
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27
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Sallee MD, Zonka JC, Skokan TD, Raftrey BC, Feldman JL. Tissue-specific degradation of essential centrosome components reveals distinct microtubule populations at microtubule organizing centers. PLoS Biol 2018; 16:e2005189. [PMID: 30080857 PMCID: PMC6103517 DOI: 10.1371/journal.pbio.2005189] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 08/21/2018] [Accepted: 07/20/2018] [Indexed: 11/19/2022] Open
Abstract
Non-centrosomal microtubule organizing centers (ncMTOCs) are found in most differentiated cells, but how these structures regulate microtubule organization and dynamics is largely unknown. We optimized a tissue-specific degradation system to test the role of the essential centrosomal microtubule nucleators γ-tubulin ring complex (γ-TuRC) and AIR-1/Aurora A at the apical ncMTOC, where they both localize in Caenorhabditis elegans embryonic intestinal epithelial cells. As at the centrosome, the core γ-TuRC component GIP-1/GCP3 is required to recruit other γ-TuRC components to the apical ncMTOC, including MZT-1/MZT1, characterized here for the first time in animal development. In contrast, AIR-1 and MZT-1 were specifically required to recruit γ-TuRC to the centrosome, but not to centrioles or to the apical ncMTOC. Surprisingly, microtubules remain robustly organized at the apical ncMTOC upon γ-TuRC and AIR-1 co-depletion, and upon depletion of other known microtubule regulators, including TPXL-1/TPX2, ZYG-9/ch-TOG, PTRN-1/CAMSAP, and NOCA-1/Ninein. However, loss of GIP-1 removed a subset of dynamic EBP-2/EB1-marked microtubules, and the remaining dynamic microtubules grew faster. Together, these results suggest that different microtubule organizing centers (MTOCs) use discrete proteins for their function, and that the apical ncMTOC is composed of distinct populations of γ-TuRC-dependent and -independent microtubules that compete for a limited pool of resources.
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Affiliation(s)
- Maria D. Sallee
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Jennifer C. Zonka
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Taylor D. Skokan
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Brian C. Raftrey
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Jessica L. Feldman
- Department of Biology, Stanford University, Stanford, California, United States of America
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28
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Sugioka K, Fielmich LE, Mizumoto K, Bowerman B, van den Heuvel S, Kimura A, Sawa H. Tumor suppressor APC is an attenuator of spindle-pulling forces during C. elegans asymmetric cell division. Proc Natl Acad Sci U S A 2018; 115:E954-E963. [PMID: 29348204 PMCID: PMC5798331 DOI: 10.1073/pnas.1712052115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The adenomatous polyposis coli (APC) tumor suppressor has dual functions in Wnt/β-catenin signaling and accurate chromosome segregation and is frequently mutated in colorectal cancers. Although APC contributes to proper cell division, the underlying mechanisms remain poorly understood. Here we show that Caenorhabditis elegans APR-1/APC is an attenuator of the pulling forces acting on the mitotic spindle. During asymmetric cell division of the C. elegans zygote, a LIN-5/NuMA protein complex localizes dynein to the cell cortex to generate pulling forces on astral microtubules that position the mitotic spindle. We found that APR-1 localizes to the anterior cell cortex in a Par-aPKC polarity-dependent manner and suppresses anterior centrosome movements. Our combined cell biological and mathematical analyses support the conclusion that cortical APR-1 reduces force generation by stabilizing microtubule plus-ends at the cell cortex. Furthermore, APR-1 functions in coordination with LIN-5 phosphorylation to attenuate spindle-pulling forces. Our results document a physical basis for the attenuation of spindle-pulling force, which may be generally used in asymmetric cell division and, when disrupted, potentially contributes to division defects in cancer.
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Affiliation(s)
- Kenji Sugioka
- Multicellular Organization Laboratory, National Institute of Genetics, 411-8540 Mishima, Japan
- RIKEN Center for Developmental Biology, Chuo-ku, 650-0047 Kobe, Japan
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Lars-Eric Fielmich
- Developmental Biology, Biology Department, Science 4 Life, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Kota Mizumoto
- RIKEN Center for Developmental Biology, Chuo-ku, 650-0047 Kobe, Japan
| | - Bruce Bowerman
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Sander van den Heuvel
- Developmental Biology, Biology Department, Science 4 Life, Utrecht University, 3584 CH Utrecht, The Netherlands;
| | - Akatsuki Kimura
- Cell Architecture Laboratory, National Institute of Genetics, 411-8540 Mishima, Japan;
- Department of Genetics, School of Life Science, Sokendai, 411-8540 Mishima, Japan
| | - Hitoshi Sawa
- Multicellular Organization Laboratory, National Institute of Genetics, 411-8540 Mishima, Japan;
- RIKEN Center for Developmental Biology, Chuo-ku, 650-0047 Kobe, Japan
- Department of Genetics, School of Life Science, Sokendai, 411-8540 Mishima, Japan
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29
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Rale MJ, Kadzik RS, Petry S. Phase Transitioning the Centrosome into a Microtubule Nucleator. Biochemistry 2017; 57:30-37. [PMID: 29256606 DOI: 10.1021/acs.biochem.7b01064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Centrosomes are self-assembling, micron-scale, nonmembrane bound organelles that nucleate microtubules (MTs) and organize the microtubule cytoskeleton of the cell. They orchestrate critical cellular processes such as ciliary-based motility, vesicle trafficking, and cell division. Much is known about the role of the centrosome in these contexts, but we have a less comprehensive understanding of how the centrosome assembles and generates microtubules. Studies over the past 10 years have fundamentally shifted our view of these processes. Subdiffraction imaging has probed the amorphous haze of material surrounding the core of the centrosome revealing a complex, hierarchically organized structure whose composition and size changes profoundly during the transition from interphase to mitosis. New biophysical insights into protein phase transitions, where a diffuse protein spontaneously separates into a locally concentrated, nonmembrane bounded compartment, have provided a fresh perspective into how the centrosome might rapidly condense from diffuse cytoplasmic components. In this Perspective, we focus on recent findings that identify several centrosomal proteins that undergo phase transitions. We discuss how to reconcile these results with the current model of the underlying organization of proteins in the centrosome. Furthermore, we reflect on how these findings impact our understanding of how the centrosome undergoes self-assembly and promotes MT nucleation.
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Affiliation(s)
- Michael J Rale
- Department of Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States
| | - Rachel S Kadzik
- Department of Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States
| | - Sabine Petry
- Department of Molecular Biology, Princeton University , Princeton, New Jersey 08544, United States
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30
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Microtubule-Organizing Centers: Towards a Minimal Parts List. Trends Cell Biol 2017; 28:176-187. [PMID: 29173799 DOI: 10.1016/j.tcb.2017.10.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 12/17/2022]
Abstract
Despite decades of molecular analysis of the centrosome, an important microtubule-organizing center (MTOC) of animal cells, the molecular basis of microtubule organization remains obscure. A major challenge is the sheer complexity of the interplay of the hundreds of proteins that constitute the centrosome. However, this complexity owes not only to the centrosome's role as a MTOC but also to the requirements of its duplication cycle and to various other functions such as the formation of cilia, the integration of various signaling pathways, and the organization of actin filaments. Thus, rather than using the parts lists to reconstruct the centrosome, we propose to identify the subset of proteins minimally needed to assemble a MTOC and to study this process at non-centrosomal sites.
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31
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DeMeyer L, Song MH. Localization of tbg-1 mRNAs and GFP::TBG-1 protein in Early C. elegans Embryos. MICROPUBLICATION BIOLOGY 2017; 2017:10.17912/W2CW8H. [PMID: 32550353 PMCID: PMC7255872 DOI: 10.17912/w2cw8h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Lauren DeMeyer
- Department of Biological Sciences, Oakland University, Rochester, MI 48309
| | - Mi Hye Song
- Department of Biological Sciences, Oakland University, Rochester, MI 48309,
Correspondence to: Mi Hye Song ()
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32
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Roostalu J, Surrey T. Microtubule nucleation: beyond the template. Nat Rev Mol Cell Biol 2017; 18:702-710. [PMID: 28831203 DOI: 10.1038/nrm.2017.75] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Microtubules are cytoskeletal filaments central to a wide range of essential cellular functions in eukaryotic cells. Consequently, cells need to exert tight control over when, where and how many microtubules are being made. Whereas the regulation of microtubule dynamics is well studied, the molecular mechanisms of microtubule nucleation are still poorly understood. Next to the established master template of nucleation, the γ-tubulin ring complex, other microtubule-associated proteins that affect microtubule dynamic properties have recently been found to contribute to nucleation. It has begun to emerge that the nucleation efficiency is controlled not only by template activity but also by, either additionally or alternatively, the stabilization of the nascent microtubule 'nucleus'. This suggests a simple conceptual framework for the mechanisms regulating microtubule nucleation in cells.
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Affiliation(s)
| | - Thomas Surrey
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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33
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Muñoz-Jiménez C, Ayuso C, Dobrzynska A, Torres-Mendéz A, Ruiz PDLC, Askjaer P. An Efficient FLP-Based Toolkit for Spatiotemporal Control of Gene Expression in Caenorhabditis elegans. Genetics 2017; 206:1763-1778. [PMID: 28646043 PMCID: PMC5560786 DOI: 10.1534/genetics.117.201012] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/19/2017] [Indexed: 02/07/2023] Open
Abstract
Site-specific recombinases are potent tools to regulate gene expression. In particular, the Cre (cyclization recombination) and FLP (flipase) enzymes are widely used to either activate or inactivate genes in a precise spatiotemporal manner. Both recombinases work efficiently in the popular model organism Caenorhabditis elegans, but their use in this nematode is still only sporadic. To increase the utility of the FLP system in C. elegans, we have generated a series of single-copy transgenic strains that stably express an optimized version of FLP in specific tissues or by heat induction. We show that recombination efficiencies reach 100% in several cell types, such as muscles, intestine, and serotonin-producing neurons. Moreover, we demonstrate that most promoters drive recombination exclusively in the expected tissues. As examples of the potentials of the FLP lines, we describe novel tools for induced cell ablation by expression of the PEEL-1 toxin and a versatile FLP-out cassette for generation of GFP-tagged conditional knockout alleles. Together with other recombinase-based reagents created by the C. elegans community, this toolkit increases the possibilities for detailed analyses of specific biological processes at developmental stages inside intact animals.
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Affiliation(s)
- Celia Muñoz-Jiménez
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Cristina Ayuso
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Agnieszka Dobrzynska
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Antonio Torres-Mendéz
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Patricia de la Cruz Ruiz
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
| | - Peter Askjaer
- Andalusian Center for Developmental Biology (CABD), CSIC/JA/Universidad Pablo de Olavide, 41013 Seville, Spain
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34
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Woodruff JB, Ferreira Gomes B, Widlund PO, Mahamid J, Honigmann A, Hyman AA. The Centrosome Is a Selective Condensate that Nucleates Microtubules by Concentrating Tubulin. Cell 2017; 169:1066-1077.e10. [PMID: 28575670 DOI: 10.1016/j.cell.2017.05.028] [Citation(s) in RCA: 418] [Impact Index Per Article: 59.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/06/2017] [Accepted: 05/15/2017] [Indexed: 01/08/2023]
Abstract
Centrosomes are non-membrane-bound compartments that nucleate microtubule arrays. They consist of nanometer-scale centrioles surrounded by a micron-scale, dynamic assembly of protein called the pericentriolar material (PCM). To study how PCM forms a spherical compartment that nucleates microtubules, we reconstituted PCM-dependent microtubule nucleation in vitro using recombinant C. elegans proteins. We found that macromolecular crowding drives assembly of the key PCM scaffold protein SPD-5 into spherical condensates that morphologically and dynamically resemble in vivo PCM. These SPD-5 condensates recruited the microtubule polymerase ZYG-9 (XMAP215 homolog) and the microtubule-stabilizing protein TPXL-1 (TPX2 homolog). Together, these three proteins concentrated tubulin ∼4-fold over background, which was sufficient to reconstitute nucleation of microtubule asters in vitro. Our results suggest that in vivo PCM is a selective phase that organizes microtubule arrays through localized concentration of tubulin by microtubule effector proteins.
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Affiliation(s)
- Jeffrey B Woodruff
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
| | - Beatriz Ferreira Gomes
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Per O Widlund
- Department of Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9 c, 40530 Gothenburg, Sweden
| | - Julia Mahamid
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
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35
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Wang S, Tang NH, Lara-Gonzalez P, Zhao Z, Cheerambathur DK, Prevo B, Chisholm AD, Desai A, Oegema K. A toolkit for GFP-mediated tissue-specific protein degradation in C. elegans. Development 2017; 144:2694-2701. [PMID: 28619826 DOI: 10.1242/dev.150094] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 06/08/2017] [Indexed: 02/05/2023]
Abstract
Proteins that are essential for embryo production, cell division and early embryonic events are frequently reused later in embryogenesis, during organismal development or in the adult. Examining protein function across these different biological contexts requires tissue-specific perturbation. Here, we describe a method that uses expression of a fusion between a GFP-targeting nanobody and a SOCS-box containing ubiquitin ligase adaptor to target GFP-tagged proteins for degradation. When combined with endogenous locus GFP tagging by CRISPR-Cas9 or with rescue of a null mutant with a GFP fusion, this approach enables routine and efficient tissue-specific protein ablation. We show that this approach works in multiple tissues - the epidermis, intestine, body wall muscle, ciliated sensory neurons and touch receptor neurons - where it recapitulates expected loss-of-function mutant phenotypes. The transgene toolkit and the strain set described here will complement existing approaches to enable routine analysis of the tissue-specific roles of C. elegans proteins.
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Affiliation(s)
- Shaohe Wang
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Ngang Heok Tang
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Pablo Lara-Gonzalez
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Zhiling Zhao
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Dhanya K Cheerambathur
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Bram Prevo
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Andrew D Chisholm
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Arshad Desai
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Karen Oegema
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
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36
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Stevens J, Spang A. Attenuation of N-glycosylation causes polarity and adhesion defects in the C. elegans embryo. J Cell Sci 2017; 130:1224-1231. [PMID: 28202691 DOI: 10.1242/jcs.189316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 02/06/2017] [Indexed: 11/20/2022] Open
Abstract
The Caenorhabditiselegans early embryo is highly polarized, requiring sequestration of cytoplasmic polarity factors at the plasma membrane. This compartmentalization aids asymmetric distribution of lipids and proteins, which is partially responsible for the fates of the daughter cells. Since most plasma membrane proteins are glycosylated, we determined the effect of attenuation of N-glycosylation on cell polarity. While polarity establishment was not perturbed, the size difference between the two cells formed in first cell division (AB and P1) was more variable in embryos with reduced N-glycosylation than in the mock-treated embryos. In addition, among other deficiencies, we observed spindle orientation defects in two-cell embryos. Moreover, cell-cell adhesion was specifically lost at the two-cell stage when N-glycosylation was reduced. This loss-of-adhesion phenotype was rescued by interfering with polarity establishment, indicating that polarity establishment enforces plasma membrane compartmentalization. Consistent with this idea, the decreased plasma membrane levels of the adhesion proteins E-cadherin and MAGI-1 in ribo-1(RNAi) embryos were restored in the absence of functional PAR-2. Our data suggest a general role for N-glycosylation in plasma membrane compartmentalization and cell polarity.
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Affiliation(s)
- Julia Stevens
- Biozentrum, University of Basel, Klingelbergstrasse 70, Basel CH-4056, Switzerland
| | - Anne Spang
- Biozentrum, University of Basel, Klingelbergstrasse 70, Basel CH-4056, Switzerland
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37
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Ferreira J, Stear JH, Saumweber H. Nucleoporins NPP-10, NPP-13 and NPP-20 are required for HCP-4 nuclear import to establish correct centromere assembly. J Cell Sci 2017; 130:963-974. [PMID: 28122936 DOI: 10.1242/jcs.196709] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/13/2017] [Indexed: 12/15/2022] Open
Abstract
Centromeres form a chromosomal platform for the assembly of the kinetochores, which are required for orderly chromosome segregation. Assembly of both centromeres and kinetochores proceeds by a step-by-step mechanism that is regulated in time and space. It has been suggested that the regulated nuclear import of centromeric proteins is involved in this process. We show that the knockdown of nucleoporins NPP-10, NPP-13 and NPP-20 in Caenorhabditiselegans affects early steps in centromere formation and sister centromere resolution, and results in severe chromosomal defects in the early embryo. These phenotypes mirror the knockdown phenotype of HCP-4 (an ortholog of mammalian CENP-C), a key factor for centromere formation and inner kinetochore assembly. HCP-4 is present in the cytoplasm during interphase. It is imported into nuclei and assembled in centromeres during prophase. Following the knockdown of NPP-10, NPP-13 and NPP-20, HCP-4 remains in the cytosol throughout prophase due to stalled import. In prometaphase and later mitotic stages after breakdown of the nuclear envelope, HCP-4 is not incorporated into centromeres. These results indicate that correct timing of the availability of HCP-4 by nuclear import is essential.
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Affiliation(s)
- Jorge Ferreira
- Cytogenetics group, Institute of Biology, Humboldt-Universität zu Berlin, Chausseestr. 117, Berlin 10115, Germany
| | - Jeffrey H Stear
- University of New South Wales, School of Medical Sciences, Sydney, New South Wales 2052, Australia
| | - Harald Saumweber
- Cytogenetics group, Institute of Biology, Humboldt-Universität zu Berlin, Chausseestr. 117, Berlin 10115, Germany
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38
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Frøkjær-Jensen C, Jain N, Hansen L, Davis MW, Li Y, Zhao D, Rebora K, Millet JRM, Liu X, Kim SK, Dupuy D, Jorgensen EM, Fire AZ. An Abundant Class of Non-coding DNA Can Prevent Stochastic Gene Silencing in the C. elegans Germline. Cell 2016; 166:343-357. [PMID: 27374334 PMCID: PMC4947018 DOI: 10.1016/j.cell.2016.05.072] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 03/31/2016] [Accepted: 05/18/2016] [Indexed: 11/30/2022]
Abstract
Cells benefit from silencing foreign genetic elements but must simultaneously avoid inactivating endogenous genes. Although chromatin modifications and RNAs contribute to maintenance of silenced states, the establishment of silenced regions will inevitably reflect underlying DNA sequence and/or structure. Here we demonstrate that a pervasive non-coding DNA feature in Caenorhabditis elegans, characterized by 10-basepair periodic An/Tn-clusters (PATCs), can license transgenes for germline expression within repressive chromatin domains. Transgenes containing natural or synthetic PATCs are resistant to position effect variegation and stochastic silencing in the germline. Among endogenous genes, intron length and PATC-character undergo dramatic changes as orthologs move from active to repressive chromatin over evolutionary time, indicating a dynamic character to the An/Tn periodicity. We propose that PATCs form the basis of a cellular immune system, identifying certain endogenous genes in heterochromatic contexts as privileged while foreign DNA can be suppressed with no requirement for a cellular memory of prior exposure.
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Affiliation(s)
- Christian Frøkjær-Jensen
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112, USA; Department of Pathology, Stanford University, Stanford, CA 94305, USA; Department of Biomedical Sciences and Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Nimit Jain
- Department of Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Loren Hansen
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - M Wayne Davis
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112, USA
| | - Yongbin Li
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Di Zhao
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Karine Rebora
- IECB, University of Bordeaux, Laboratoire ARNA-INSERM, U869, 33600 Pessac, France
| | - Jonathan R M Millet
- IECB, University of Bordeaux, Laboratoire ARNA-INSERM, U869, 33600 Pessac, France
| | - Xiao Liu
- Department of Developmental Biology, Stanford University Medical Center, Stanford, CA 94305, USA; School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Stuart K Kim
- Department of Developmental Biology, Stanford University Medical Center, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Denis Dupuy
- IECB, University of Bordeaux, Laboratoire ARNA-INSERM, U869, 33600 Pessac, France
| | - Erik M Jorgensen
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112, USA.
| | - Andrew Z Fire
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
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39
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Rahman MM, Munzig M, Kaneshiro K, Lee B, Strome S, Müller-Reichert T, Cohen-Fix O. Caenorhabditis elegans polo-like kinase PLK-1 is required for merging parental genomes into a single nucleus. Mol Biol Cell 2015; 26:4718-35. [PMID: 26490119 PMCID: PMC4678026 DOI: 10.1091/mbc.e15-04-0244] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/13/2015] [Indexed: 11/11/2022] Open
Abstract
Before the first zygotic division, the nuclear envelopes of the maternal and paternal pronuclei disassemble, allowing both sets of chromosomes to be incorporated into a single nucleus in daughter cells after mitosis. We found that in Caenorhabditis elegans, partial inactivation of the polo-like kinase PLK-1 causes the formation of two nuclei, containing either the maternal or paternal chromosomes, in each daughter cell. These two nuclei gave rise to paired nuclei in all subsequent cell divisions. The paired-nuclei phenotype was caused by a defect in forming a gap in the nuclear envelopes at the interface between the two pronuclei during the first mitotic division. This was accompanied by defects in chromosome congression and alignment of the maternal and paternal metaphase plates relative to each other. Perturbing chromosome congression by other means also resulted in failure to disassemble the nuclear envelope between the two pronuclei. Our data further show that PLK-1 is needed for nuclear envelope breakdown during early embryogenesis. We propose that during the first zygotic division, PLK-1-dependent chromosome congression and metaphase plate alignment are necessary for the disassembly of the nuclear envelope between the two pronuclei, ultimately allowing intermingling of the maternal and paternal chromosomes.
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Affiliation(s)
- Mohammad M Rahman
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Mandy Munzig
- Structural Cell Biology Group, Experimental Center, Medical Faculty Carl Gustav Carus, University of Technology Dresden, 01307 Dresden, Germany
| | - Kiyomi Kaneshiro
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Brandon Lee
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Susan Strome
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064
| | - Thomas Müller-Reichert
- Structural Cell Biology Group, Experimental Center, Medical Faculty Carl Gustav Carus, University of Technology Dresden, 01307 Dresden, Germany
| | - Orna Cohen-Fix
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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40
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PUF-8 Functions Redundantly with GLD-1 to Promote the Meiotic Progression of Spermatocytes in Caenorhabditis elegans. G3-GENES GENOMES GENETICS 2015; 5:1675-84. [PMID: 26068572 PMCID: PMC4528324 DOI: 10.1534/g3.115.019521] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Successful meiotic progression of germ cells is crucial for gametogenesis. Defects in this process affect proper genetic transmission and sometimes lead to tumor formation in the germline. In Caenorhabditis elegans, the RNA-binding protein GLD-1 is essential for the meiotic development of oocytes. However, its role during spermatogenesis has not been understood. Here, we show that GLD-1 functions redundantly with the PUF family protein PUF-8 to ensure proper meiotic development of spermatocytes. When grown at 20°-the standard laboratory temperature for C. elegans growth-primary spermatocytes in both gld-1 and puf-8 single-mutant males and hermaphrodites complete the meiotic divisions normally. By contrast, some of the gld-1; puf-8 double-mutant spermatocytes exit meiosis and form germ cell tumors in both sexes. During larval development, gld-1; puf-8 double-mutant germ cells begin to express the meiotic marker HIM-3, lose P granules, and form the sperm-specific membranous organelle, which are characteristics of developing spermatocytes. However, some of these cells quickly lose HIM-3 and form germ cell tumors that lack membranous organelle but contain P granules. Mutations that block meiotic progression at late pachytene or diakinetic stage fail to arrest the tumorigenesis, suggesting that the gld-1; puf-8 double-mutant spermatocytes exit meiosis prior to the completion of pachytene. Together, results presented here uncover a novel function for gld-1 in the meiotic development of spermatocytes in both hermaphrodites and males.
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Hench J, Henriksson J, Abou-Zied AM, Lüppert M, Dethlefsen J, Mukherjee K, Tong YG, Tang L, Gangishetti U, Baillie DL, Bürglin TR. The Homeobox Genes of Caenorhabditis elegans and Insights into Their Spatio-Temporal Expression Dynamics during Embryogenesis. PLoS One 2015; 10:e0126947. [PMID: 26024448 PMCID: PMC4448998 DOI: 10.1371/journal.pone.0126947] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 04/09/2015] [Indexed: 11/18/2022] Open
Abstract
Homeobox genes play crucial roles for the development of multicellular eukaryotes. We have generated a revised list of all homeobox genes for Caenorhabditis elegans and provide a nomenclature for the previously unnamed ones. We show that, out of 103 homeobox genes, 70 are co-orthologous to human homeobox genes. 14 are highly divergent, lacking an obvious ortholog even in other Caenorhabditis species. One of these homeobox genes encodes 12 homeodomains, while three other highly divergent homeobox genes encode a novel type of double homeodomain, termed HOCHOB. To understand how transcription factors regulate cell fate during development, precise spatio-temporal expression data need to be obtained. Using a new imaging framework that we developed, Endrov, we have generated spatio-temporal expression profiles during embryogenesis of over 60 homeobox genes, as well as a number of other developmental control genes using GFP reporters. We used dynamic feedback during recording to automatically adjust the camera exposure time in order to increase the dynamic range beyond the limitations of the camera. We have applied the new framework to examine homeobox gene expression patterns and provide an analysis of these patterns. The methods we developed to analyze and quantify expression data are not only suitable for C. elegans, but can be applied to other model systems or even to tissue culture systems.
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Affiliation(s)
- Jürgen Hench
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Johan Henriksson
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Akram M. Abou-Zied
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Martin Lüppert
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Johan Dethlefsen
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Krishanu Mukherjee
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Yong Guang Tong
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Lois Tang
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
| | - Umesh Gangishetti
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
| | - David L. Baillie
- Dept. of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada
| | - Thomas R. Bürglin
- Dept. of Biosciences and Nutrition & Center for Biosciences, Karolinska Institutet, Hälsovägen 7, Novum, SE-141 83, Huddinge, Sweden
- School of Life Sciences, Södertörns Högskola, Huddinge, Sweden
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42
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Vora S, Phillips BT. Centrosome-Associated Degradation Limits β-Catenin Inheritance by Daughter Cells after Asymmetric Division. Curr Biol 2015; 25:1005-16. [PMID: 25819561 DOI: 10.1016/j.cub.2015.02.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/02/2015] [Accepted: 02/04/2015] [Indexed: 01/01/2023]
Abstract
Caenorhabditis elegans embryos rapidly diversify cell fate using a modified Wnt/β-catenin signaling strategy to carry out serial asymmetric cell divisions (ACDs). Wnt-dependent ACDs rely on nuclear asymmetry of the transcriptional coactivator SYS-1/β-catenin between daughter cells to differentially activate Wnt-responsive target genes. Here, we investigate how dynamic localization of SYS-1 to mitotic centrosomes influences SYS-1 inheritance in daughter cells and cell-fate outcomes after ACD. Through yeast two-hybrid screening, we identify the centrosomal protein RSA-2 as a SYS-1 binding partner and show that localization of SYS-1 to mitotic centrosomes is dependent on RSA-2. Uncoupling SYS-1 from the centrosome by RSA-2 depletion increases SYS-1 inheritance after ACD and promotes Wnt-dependent cell fate. Photobleaching experiments reveal that centrosome-bound SYS-1 turns over rapidly. Interestingly, disruption of the proteasome leads to an increased accumulation of SYS-1 at the centrosome but disrupts its dynamic turnover. We conclude that centrosomal targeting of SYS-1 promotes its degradation during asymmetric cell division. We propose a model whereby centrosome-associated SYS-1 degradation couples negative regulation with cell-division timing to facilitate SYS-1 clearance from the mother cell at the time of asymmetric division. Based on our observations of centrosomal SYS-1 dynamics, we discuss the possibility that the centrosome may coordinate various cell-cycle-dependent processes by synchronizing mitosis and protein regulation.
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Affiliation(s)
- Setu Vora
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Bryan T Phillips
- Department of Biology, University of Iowa, Iowa City, IA 52242, USA.
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Dejima K, Kang S, Mitani S, Cosman PC, Chisholm AD. Syndecan defines precise spindle orientation by modulating Wnt signaling in C. elegans. Development 2014; 141:4354-65. [PMID: 25344071 DOI: 10.1242/dev.113266] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Wnt signals orient mitotic spindles in development, but it remains unclear how Wnt signaling is spatially controlled to achieve precise spindle orientation. Here, we show that C. elegans syndecan (SDN-1) is required for precise orientation of a mitotic spindle in response to a Wnt cue. We find that SDN-1 is the predominant heparan sulfate (HS) proteoglycan in the early C. elegans embryo, and that loss of HS biosynthesis or of the SDN-1 core protein results in misorientation of the spindle of the ABar blastomere. The ABar and EMS spindles both reorient in response to Wnt signals, but only ABar spindle reorientation is dependent on a new cell contact and on HS and SDN-1. SDN-1 transiently accumulates on the ABar surface as it contacts C, and is required for local concentration of Dishevelled (MIG-5) in the ABar cortex adjacent to C. These findings establish a new role for syndecan in Wnt-dependent spindle orientation.
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Affiliation(s)
- Katsufumi Dejima
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Sukryool Kang
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92037-0407, USA
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Pamela C Cosman
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA 92037-0407, USA
| | - Andrew D Chisholm
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Vágnerová L, Gombitová A, Cmarko D, Lanctôt C. Distinct chromatin organization in the germ line founder cell of the Caenorhabditis elegans embryo. Dev Growth Differ 2014; 56:605-14. [PMID: 25279455 DOI: 10.1111/dgd.12160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 08/21/2014] [Accepted: 08/21/2014] [Indexed: 12/01/2022]
Abstract
Cells belonging to the germ lineage segregate physically and molecularly from their somatic neighbors during embryogenesis. While germ line-specific chromatin modifications have been identified at later stages in the Caenorhabditis elegans nematode, none have been found in the single P4 germ line founder cell that arises at the beginning of gastrulation. Using light and electron microscopy, we now report that the chromatin organization in the germ line founder cell of the early C. elegans embryo is distinct from that in the neighboring somatic cells. This unique organization is characterized by a greater chromatin compaction and an expansion of the interchromatin compartment. The ultrastructure of individual chromatin domains does not differ between germ line and somatic cells, pointing to a specific organization mainly at the level of the whole nucleus. We show that this higher order reorganization of chromatin is not a consequence of the P4 nucleus being smaller than somatic nuclei or having initiated mitosis. Imaging of living embryos expressing fluorescent markers for both chromatin and P granules revealed that the appearance of a distinct chromatin organization in the P4 cell occurs approximately 10 min after its birth and coincides with the aggregation of P granules around the nucleus, suggesting a possible link between these two events. The higher order reorganization of chromatin that is reported here occurs during the establishment of definitive germ cell identity. The changes we have observed could therefore be a prerequisite for the programming of chromatin totipotency.
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Affiliation(s)
- Lenka Vágnerová
- Institute of Cellular Biology and Pathology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
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45
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Paz-Gómez D, Villanueva-Chimal E, Navarro RE. The DEAD Box RNA helicase VBH-1 is a new player in the stress response in C. elegans. PLoS One 2014; 9:e97924. [PMID: 24844228 PMCID: PMC4028217 DOI: 10.1371/journal.pone.0097924] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 04/25/2014] [Indexed: 12/29/2022] Open
Abstract
For several years, DEAD box RNA helicase Vasa (DDX4) has been used as a bona fide germline marker in different organisms. C. elegans VBH-1 is a close homolog of the Vasa protein, which plays an important role in gametogenesis, germ cell survival and embryonic development. Here, we show that VBH-1 protects nematodes from heat shock and oxidative stress. Using the germline-defective mutant glp-4(bn2) we found that a potential somatic expression of vbh-1 might be important for stress survival. We also show that the VBH-1 paralog LAF-1 is important for stress survival, although this protein is not redundant with its counterpart. Furthermore, we observed that the mRNAs of the heat shock proteins hsp-1 and sip-1 are downregulated when vbh-1 or laf-1 are silenced. Previously, we reported that in C. elegans, VBH-1 was primarily expressed in P granules of germ cells and in the cytoplasm of all blastomeres. Here we show that during stress, VBH-1 co-localizes with CGH-1 in large aggregates in the gonad core and oocytes; however, VBH-1 aggregates do not overlap with CGH-1 foci in early embryos under the same conditions. These data demonstrate that, in addition to the previously described role for this protein in the germline, VBH-1 plays an important role during the stress response in C. elegans through the potential direct or indirect regulation of stress response mRNAs.
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Affiliation(s)
- Daniel Paz-Gómez
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Distrito Federal, México
| | - Emmanuel Villanueva-Chimal
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Distrito Federal, México
| | - Rosa E. Navarro
- Departamento de Biología Celular y Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México, Distrito Federal, México
- * E-mail:
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46
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Askjaer P, Galy V, Meister P. Modern Tools to Study Nuclear Pore Complexes and Nucleocytoplasmic Transport in Caenorhabditis elegans. Methods Cell Biol 2014; 122:277-310. [DOI: 10.1016/b978-0-12-417160-2.00013-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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47
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N-glycosylation is required for secretion and mitosis in C. elegans. PLoS One 2013; 8:e63687. [PMID: 23691084 PMCID: PMC3653792 DOI: 10.1371/journal.pone.0063687] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 04/04/2013] [Indexed: 01/15/2023] Open
Abstract
N-glycosylation of proteins is an essential process, and N-glucans serve as important beacons in protein folding and ER associated degradation. More importantly, N-glycosylation increases the structural repertoire of proteins because the addition of the N-glucan on proteins will serve as a base for further sugar additions in the Golgi apparatus, and hence complex three-dimensional structures can be build. N-glycosylation is mediated by the ER-resident OST complex, which is essential throughout eukaryotes. Partial knockdown of conserved OST complex members, such as C. elegans RIBO-1, led to an embryonic lethal phenotype. Although the ER morphology was not grossly altered in ribo-1(RNAi) oocytes and embryos, secretion of yolk and of the yolk receptor RME-2 was perturbed in those worms. Perhaps as a consequence of reduced arrival of N-glycosylated proteins at the plasma membrane, cytokinesis occurred less efficiently leading to multinuclear cells. Unexpectedly, we detected a chromosome segregation defect in ribo-1(RNAi) embryos suggesting an essential role of at least one N-glycosylated protein in metaphase-anaphase transition.
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Kress E, Schwager F, Holtackers R, Seiler J, Prodon F, Zanin E, Eiteneuer A, Toya M, Sugimoto A, Meyer H, Meraldi P, Gotta M. The UBXN-2/p37/p47 adaptors of CDC-48/p97 regulate mitosis by limiting the centrosomal recruitment of Aurora A. ACTA ACUST UNITED AC 2013; 201:559-75. [PMID: 23649807 PMCID: PMC3653362 DOI: 10.1083/jcb.201209107] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
UBXN-2, a substrate adaptor of the AAA ATPase CDC-48/p97, is required to coordinate centrosome maturation timing with mitosis. Coordination of cell cycle events in space and time is crucial to achieve a successful cell division. Here, we demonstrate that UBXN-2, a substrate adaptor of the AAA ATPase Cdc48/p97, is required to coordinate centrosome maturation timing with mitosis. In UBXN-2–depleted Caenorhabditis elegans embryos, centrosomes recruited more AIR-1 (Aurora A), matured precociously, and alignment of the mitotic spindle with the axis of polarity was impaired. UBXN-2 and CDC-48 coimmunoprecipitated with AIR-1 and the spindle alignment defect was partially rescued by co-depleting AIR-1, indicating that UBXN-2 controls these processes via AIR-1. Similarly, depletion in human cells of the UBXN-2 orthologues p37/p47 resulted in an accumulation of Aurora A at centrosomes and a delay in centrosome separation. The latter defect was also rescued by inhibiting Aurora A. We therefore postulate that the role of this adaptor in cell cycle regulation is conserved.
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Affiliation(s)
- Elsa Kress
- Department of Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
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Pushpa K, Kumar GA, Subramaniam K. PUF-8 and TCER-1 are essential for normal levels of multiple mRNAs in the C. elegans germline. Development 2013; 140:1312-20. [PMID: 23444359 PMCID: PMC3585663 DOI: 10.1242/dev.087833] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PUF family proteins are well-conserved regulators of cell proliferation in different developmental processes. They regulate target mRNAs by promoting degradation or by influencing translation through interaction with the translation initiation machinery. Here we show that Caenorhabditis elegans PUF-8 functions redundantly with the nuclear protein TCER-1 in the post-transcriptional maintenance of at least six germline mRNAs. The levels of spliced mRNAs in the puf-8(-) tcer-1(-) double mutant are only 10-30% of the wild type, whereas the unspliced forms increase by ∼2- to 3-fold compared with the wild type. These two proteins colocalise at the inner nuclear periphery, and their absence leads to reduced germ cell proliferation and to sterility. A yeast two-hybrid screen of 31 components of the nuclear pore complex and mRNA processing machineries identified seven proteins involved in mRNA export as potential partners of PUF-8. One of these, the nuclear cap-binding protein NCBP-2, colocalises with PUF-8 in the nucleus. A 50 amino acid N-terminal domain of PUF-8 is essential for interaction with NCBP-2 and for PUF-8 to function redundantly with TCER-1. These results reveal two important unexpected aspects of PUF proteins: that, in addition to the C-terminal PUF domain, the N-terminal domain is crucial for PUF function, and that PUF proteins have a novel role in mRNA maintenance. We propose that PUF proteins, in addition to their known cytoplasmic roles, participate in nuclear processing and/or export of mRNAs.
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Affiliation(s)
- Kumari Pushpa
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
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50
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Vaid S, Ariz M, Chaturbedi A, Kumar GA, Subramaniam K. PUF-8 negatively regulates RAS/MAPK signalling to promote differentiation of C. elegans germ cells. Development 2013; 140:1645-54. [PMID: 23487310 PMCID: PMC3621483 DOI: 10.1242/dev.088013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/29/2013] [Indexed: 12/30/2022]
Abstract
Signals that promote germ cell self-renewal by preventing premature meiotic entry are well understood. However, signals that control mitotic proliferation to promote meiotic differentiation have not been well characterized. In Caenorhabditis elegans, GLP-1 Notch signalling promotes the proliferative fate by preventing premature meiotic entry. The germline niche cell, which is the source of the ligand for GLP-1, spatially restricts GLP-1 signalling and thus enables the germ cells that have moved away from the niche to enter meiosis. Here, we show that the suppression of RAS/MAP kinase signalling in the mitotic and meiotic-entry regions is essential for the regulation of the mitosis-meiosis switch by niche signalling. We provide evidence that the conserved PUF family RNA-binding protein PUF-8 and the RAS GAP protein GAP-3 function redundantly to suppress the LET-60 RAS in the mitotic and meiotic entry regions. Germ cells missing both PUF-8 and GAP-3 proliferate in an uncontrolled fashion and fail to undergo meiotic development. MPK-1, the MAP kinase downstream of the LET-60 RAS, is prematurely activated in these cells; downregulation of MPK-1 activation eliminates tumours and restores differentiation. Our results further reveal that PUF-8 negatively regulates LET-60 expression at a post-transcriptional step. LET-60 is misexpressed in the puf-8(-) mutant germlines and PUF-8 physically interacts with the let-60 3' UTR. Furthermore, PUF-8 suppresses let-60 3' UTR-mediated expression in the germ cells that are transitioning from the mitotic to meiotic fate. These results reveal that PUF-8-mediated inhibition of the RAS/MAPK pathway is essential for mitotic-to-meiotic fate transition.
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Affiliation(s)
- Samir Vaid
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Mohd Ariz
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Amaresh Chaturbedi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Ganga Anil Kumar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
| | - Kuppuswamy Subramaniam
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur 208016, India
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