1
|
Walsh ME, King GA, Ünal E. Not just binary: embracing the complexity of nuclear division dynamics. Nucleus 2024; 15:2360601. [PMID: 38842147 PMCID: PMC11164224 DOI: 10.1080/19491034.2024.2360601] [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: 02/09/2024] [Accepted: 05/22/2024] [Indexed: 06/07/2024] Open
Abstract
Cell division presents a challenge for eukaryotic cells: how can chromosomes effectively segregate within the confines of a membranous nuclear compartment? Different organisms have evolved diverse solutions by modulating the degree of nuclear compartmentalization, ranging from complete nuclear envelope breakdown to complete maintenance of nuclear compartmentalization via nuclear envelope expansion. Many intermediate forms exist between these extremes, suggesting that nuclear dynamics during cell division are surprisingly plastic. In this review, we highlight the evolutionary diversity of nuclear divisions, focusing on two defining characteristics: (1) chromosome compartmentalization and (2) nucleocytoplasmic transport. Further, we highlight recent evidence that nuclear behavior during division can vary within different cellular contexts in the same organism. The variation observed within and between organisms underscores the dynamic evolution of nuclear divisions tailored to specific contexts and cellular requirements. In-depth investigation of diverse nuclear divisions will enhance our understanding of the nucleus, both in physiological and pathological states.
Collapse
Affiliation(s)
- Madison E. Walsh
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| | - Grant A. King
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| | - Elçin Ünal
- Department of Molecular and Cell Biology, Barker Hall, University of California, Berkeley, CA, USA
| |
Collapse
|
2
|
Shah H, Olivetta M, Bhickta C, Ronchi P, Trupinić M, Tromer EC, Tolić IM, Schwab Y, Dudin O, Dey G. Life-cycle-coupled evolution of mitosis in close relatives of animals. Nature 2024; 630:116-122. [PMID: 38778110 PMCID: PMC11153136 DOI: 10.1038/s41586-024-07430-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 04/16/2024] [Indexed: 05/25/2024]
Abstract
Eukaryotes have evolved towards one of two extremes along a spectrum of strategies for remodelling the nuclear envelope during cell division: disassembling the nuclear envelope in an open mitosis or constructing an intranuclear spindle in a closed mitosis1,2. Both classes of mitotic remodelling involve key differences in the core division machinery but the evolutionary reasons for adopting a specific mechanism are unclear. Here we use an integrated comparative genomics and ultrastructural imaging approach to investigate mitotic strategies in Ichthyosporea, close relatives of animals and fungi. We show that species in this clade have diverged towards either a fungal-like closed mitosis or an animal-like open mitosis, probably to support distinct multinucleated or uninucleated states. Our results indicate that multinucleated life cycles favour the evolution of closed mitosis.
Collapse
Affiliation(s)
- Hiral Shah
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
| | - Marine Olivetta
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland
| | - Chandni Bhickta
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Monika Trupinić
- Division of Molecular Biology, Ruđer Bošković Institute (RBI), Zagreb, Croatia
| | - Eelco C Tromer
- Cell Biochemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Iva M Tolić
- Division of Molecular Biology, Ruđer Bošković Institute (RBI), Zagreb, Croatia
| | - Yannick Schwab
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Omaya Dudin
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
| | - Gautam Dey
- Cell Biology and Biophysics, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
| |
Collapse
|
3
|
Rush C, Jiang Z, Tingey M, Feng F, Yang W. Unveiling the complexity: assessing models describing the structure and function of the nuclear pore complex. Front Cell Dev Biol 2023; 11:1245939. [PMID: 37876551 PMCID: PMC10591098 DOI: 10.3389/fcell.2023.1245939] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 09/19/2023] [Indexed: 10/26/2023] Open
Abstract
The nuclear pore complex (NPC) serves as a pivotal subcellular structure, acting as a gateway that orchestrates nucleocytoplasmic transport through a selectively permeable barrier. Nucleoporins (Nups), particularly those containing phenylalanine-glycine (FG) motifs, play indispensable roles within this barrier. Recent advancements in technology have significantly deepened our understanding of the NPC's architecture and operational intricacies, owing to comprehensive investigations. Nevertheless, the conspicuous presence of intrinsically disordered regions within FG-Nups continues to present a formidable challenge to conventional static characterization techniques. Historically, a multitude of strategies have been employed to unravel the intricate organization and behavior of FG-Nups within the NPC. These endeavors have given rise to multiple models that strive to elucidate the structural layout and functional significance of FG-Nups. Within this exhaustive review, we present a comprehensive overview of these prominent models, underscoring their proposed dynamic and structural attributes, supported by pertinent research. Through a comparative analysis, we endeavor to shed light on the distinct characteristics and contributions inherent in each model. Simultaneously, it remains crucial to acknowledge the scarcity of unequivocal validation for any of these models, as substantiated by empirical evidence.
Collapse
Affiliation(s)
| | | | | | | | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, PA, United States
| |
Collapse
|
4
|
Santana-Sosa S, Matos-Perdomo E, Ayra-Plasencia J, Machín F. A Yeast Mitotic Tale for the Nucleus and the Vacuoles to Embrace. Int J Mol Sci 2023; 24:9829. [PMID: 37372977 DOI: 10.3390/ijms24129829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
The morphology of the nucleus is roughly spherical in most eukaryotic cells. However, this organelle shape needs to change as the cell travels through narrow intercellular spaces during cell migration and during cell division in organisms that undergo closed mitosis, i.e., without dismantling the nuclear envelope, such as yeast. In addition, the nuclear morphology is often modified under stress and in pathological conditions, being a hallmark of cancer and senescent cells. Thus, understanding nuclear morphological dynamics is of uttermost importance, as pathways and proteins involved in nuclear shaping can be targeted in anticancer, antiaging, and antifungal therapies. Here, we review how and why the nuclear shape changes during mitotic blocks in yeast, introducing novel data that associate these changes with both the nucleolus and the vacuole. Altogether, these findings suggest a close relationship between the nucleolar domain of the nucleus and the autophagic organelle, which we also discuss here. Encouragingly, recent evidence in tumor cell lines has linked aberrant nuclear morphology to defects in lysosomal function.
Collapse
Affiliation(s)
- Silvia Santana-Sosa
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Emiliano Matos-Perdomo
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Jessel Ayra-Plasencia
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
| | - Félix Machín
- Research Unit, University Hospital Ntra Sra de Candelaria, Ctra del Rosario 145, 38010 Santa Cruz de Tenerife, Spain
- Institute of Biomedical Technologies, University of La Laguna, 38200 San Cristóbal de La Laguna, Spain
- Faculty of Health Sciences, Fernando Pessoa Canarias University, 35450 Santa María de Guía, Spain
| |
Collapse
|
5
|
Wenz C, Simon CS, Romão TP, Stürmer VS, Machado M, Klages N, Klemmer A, Voß Y, Ganter M, Brochet M, Guizetti J. An Sfi1-like centrin-interacting centriolar plaque protein affects nuclear microtubule homeostasis. PLoS Pathog 2023; 19:e1011325. [PMID: 37130129 PMCID: PMC10180636 DOI: 10.1371/journal.ppat.1011325] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/12/2023] [Accepted: 03/28/2023] [Indexed: 05/03/2023] Open
Abstract
Malaria-causing parasites achieve rapid proliferation in human blood through multiple rounds of asynchronous nuclear division followed by daughter cell formation. Nuclear divisions critically depend on the centriolar plaque, which organizes intranuclear spindle microtubules. The centriolar plaque consists of an extranuclear compartment, which is connected via a nuclear pore-like structure to a chromatin-free intranuclear compartment. Composition and function of this non-canonical centrosome remain largely elusive. Centrins, which reside in the extranuclear part, are among the very few centrosomal proteins conserved in Plasmodium falciparum. Here we identify a novel centrin-interacting centriolar plaque protein. Conditional knock down of this Sfi1-like protein (PfSlp) caused a growth delay in blood stages, which correlated with a reduced number of daughter cells. Surprisingly, intranuclear tubulin abundance was significantly increased, which raises the hypothesis that the centriolar plaque might be implicated in regulating tubulin levels. Disruption of tubulin homeostasis caused excess microtubules and aberrant mitotic spindles. Time-lapse microscopy revealed that this prevented or delayed mitotic spindle extension but did not significantly interfere with DNA replication. Our study thereby identifies a novel extranuclear centriolar plaque factor and establishes a functional link to the intranuclear compartment of this divergent eukaryotic centrosome.
Collapse
Affiliation(s)
- Christoph Wenz
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | | | | | | | - Marta Machado
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
- Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Natacha Klages
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anja Klemmer
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Yannik Voß
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Markus Ganter
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Guizetti
- Center for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| |
Collapse
|
6
|
Bremer N, Tria FDK, Skejo J, Martin WF. The Ancestral Mitotic State: Closed Orthomitosis With Intranuclear Spindles in the Syncytial Last Eukaryotic Common Ancestor. Genome Biol Evol 2023; 15:7031494. [PMID: 36752808 PMCID: PMC9985178 DOI: 10.1093/gbe/evad016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/26/2023] [Accepted: 02/03/2023] [Indexed: 02/09/2023] Open
Abstract
All eukaryotes have linear chromosomes that are distributed to daughter nuclei during mitotic division, but the ancestral state of nuclear division in the last eukaryotic common ancestor (LECA) is so far unresolved. To address this issue, we have employed ancestral state reconstructions for mitotic states that can be found across the eukaryotic tree concerning the intactness of the nuclear envelope during mitosis (open or closed), the position of spindles (intranuclear or extranuclear), and the symmetry of spindles being either axial (orthomitosis) or bilateral (pleuromitosis). The data indicate that the LECA possessed closed orthomitosis with intranuclear spindles. Our reconstruction is compatible with recent findings indicating a syncytial state of the LECA, because it decouples three main processes: chromosome division, chromosome partitioning, and cell division (cytokinesis). The possession of closed mitosis using intranuclear spindles adds to the number of cellular traits that can now be attributed to LECA, providing insights into the lifestyle of this otherwise elusive biological entity at the origin of eukaryotic cells. Closed mitosis in a syncytial eukaryotic common ancestor would buffer mutations arising at the origin of mitotic division by allowing nuclei with viable chromosome sets to complement defective nuclei via mRNA in the cytosol.
Collapse
Affiliation(s)
- Nico Bremer
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Fernando D K Tria
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Josip Skejo
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| |
Collapse
|
7
|
Tingey M, Li Y, Yu W, Young A, Yang W. Spelling out the roles of individual nucleoporins in nuclear export of mRNA. Nucleus 2022; 13:170-193. [PMID: 35593254 PMCID: PMC9132428 DOI: 10.1080/19491034.2022.2076965] [Citation(s) in RCA: 8] [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: 01/21/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 11/01/2022] Open
Abstract
The Nuclear Pore Complex (NPC) represents a critical passage through the nuclear envelope for nuclear import and export that impacts nearly every cellular process at some level. Recent technological advances in the form of Auxin Inducible Degron (AID) strategies and Single-Point Edge-Excitation sub-Diffraction (SPEED) microscopy have enabled us to provide new insight into the distinct functions and roles of nuclear basket nucleoporins (Nups) upon nuclear docking and export for mRNAs. In this paper, we provide a review of our recent findings as well as an assessment of new techniques, updated models, and future perspectives in the studies of mRNA's nuclear export.
Collapse
Affiliation(s)
- Mark Tingey
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Yichen Li
- Department of Genetics, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Wenlan Yu
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Albert Young
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| | - Weidong Yang
- Department of Biology, Temple University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
8
|
Araújo M, Tavares A, Vieira DV, Telley IA, Oliveira RA. Endoplasmic reticulum membranes are continuously required to maintain mitotic spindle size and forces. Life Sci Alliance 2022; 6:6/1/e202201540. [PMID: 36379670 PMCID: PMC9671068 DOI: 10.26508/lsa.202201540] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022] Open
Abstract
Membrane organelle function, localization, and proper partitioning upon cell division depend on interactions with the cytoskeleton. Whether membrane organelles also impact the function of cytoskeletal elements remains less clear. Here, we show that acute disruption of the ER around spindle poles affects mitotic spindle size and function in Drosophila syncytial embryos. Acute ER disruption was achieved through the inhibition of ER membrane fusion by the dominant-negative cytoplasmic domain of atlastin. We reveal that when centrosome-proximal ER membranes are disrupted, specifically at metaphase, mitotic spindles become smaller, despite no significant changes in microtubule dynamics. These smaller spindles are still able to mediate sister chromatid separation, yet with decreased velocity. Furthermore, by inducing mitotic exit, we found that nuclear separation and distribution are affected by ER disruption. Our results suggest that ER integrity around spindle poles is crucial for the maintenance of mitotic spindle shape and pulling forces. In addition, ER integrity also ensures nuclear spacing during syncytial divisions.
Collapse
Affiliation(s)
| | | | | | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Raquel A Oliveira
- Instituto Gulbenkian de Ciência, Oeiras, Portugal .,Universidade Católica Portuguesa, Católica Medical School, Católica Biomedical Research Centre, Lisbon, Portugal
| |
Collapse
|
9
|
Torisawa T, Kimura A. Sequential accumulation of dynein and its regulatory proteins at the spindle region in the Caenorhabditis elegans embryo. Sci Rep 2022; 12:11740. [PMID: 35817834 PMCID: PMC9273622 DOI: 10.1038/s41598-022-15042-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 06/16/2022] [Indexed: 11/09/2022] Open
Abstract
Cytoplasmic dynein is responsible for various cellular processes during the cell cycle. The mechanism by which its activity is regulated spatially and temporarily inside the cell remains elusive. There are various regulatory proteins of dynein, including dynactin, NDEL1/NUD-2, and LIS1. Characterizing the spatiotemporal localization of regulatory proteins in vivo will aid understanding of the cellular regulation of dynein. Here, we focused on spindle formation in the Caenorhabditis elegans early embryo, wherein dynein and its regulatory proteins translocated from the cytoplasm to the spindle region upon nuclear envelope breakdown (NEBD). We found that (i) a limited set of dynein regulatory proteins accumulated in the spindle region, (ii) the spatial localization patterns were distinct among the regulators, and (iii) the regulatory proteins did not accumulate in the spindle region simultaneously but sequentially. Furthermore, the accumulation of NUD-2 was unique among the regulators. NUD-2 started to accumulate before NEBD (pre-NEBD accumulation), and exhibited the highest enrichment compared to the cytoplasmic concentration. Using a protein injection approach, we revealed that the C-terminal helix of NUD-2 was responsible for pre-NEBD accumulation. These findings suggest a fine temporal control of the subcellular localization of regulatory proteins.
Collapse
Affiliation(s)
- Takayuki Torisawa
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan.,Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, Japan
| | - Akatsuki Kimura
- Cell Architecture Laboratory, National Institute of Genetics, Mishima, Japan. .,Department of Genetics, The Graduate University for Advanced Studies, Sokendai, Mishima, Japan.
| |
Collapse
|
10
|
von der Heyde EL, Hallmann A. Molecular and cellular dynamics of early embryonic cell divisions in Volvox carteri. THE PLANT CELL 2022; 34:1326-1353. [PMID: 35018470 PMCID: PMC9026201 DOI: 10.1093/plcell/koac004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Cell division is fundamental to all organisms and the green alga used here exhibits both key animal and plant functions. Specifically, we analyzed the molecular and cellular dynamics of early embryonic divisions of the multicellular green alga Volvox carteri (Chlamydomonadales). Relevant proteins related to mitosis and cytokinesis were identified in silico, the corresponding genes were cloned, fused to yfp, and stably expressed in Volvox, and the tagged proteins were studied by live-cell imaging. We reveal rearrangements of the microtubule cytoskeleton during centrosome separation, spindle formation, establishment of the phycoplast, and generation of previously unknown structures. The centrosomes participate in initiation of spindle formation and determination of spindle orientation. Although the nuclear envelope does not break down during early mitosis, intermixing of cytoplasm and nucleoplasm results in loss of nuclear identity. Finally, we present a model for mitosis in Volvox. Our study reveals enormous dynamics, clarifies spatio-temporal relationships of subcellular structures, and provides insight into the evolution of cell division.
Collapse
Affiliation(s)
- Eva Laura von der Heyde
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| |
Collapse
|
11
|
El Dika M, Fritz AJ, Toor RH, Rodriguez PD, Foley SJ, Ullah R, Nie D, Banerjee B, Lohese D, Glass KC, Frietze S, Ghule PN, Heath JL, Imbalzano AN, van Wijnen A, Gordon J, Lian JB, Stein JL, Stein GS, Stein GS. Epigenetic-Mediated Regulation of Gene Expression for Biological Control and Cancer: Fidelity of Mechanisms Governing the Cell Cycle. Results Probl Cell Differ 2022; 70:375-396. [PMID: 36348115 PMCID: PMC9703624 DOI: 10.1007/978-3-031-06573-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cell cycle is governed by stringent epigenetic mechanisms that, in response to intrinsic and extrinsic regulatory cues, support fidelity of DNA replication and cell division. We will focus on (1) the complex and interdependent processes that are obligatory for control of proliferation and compromised in cancer, (2) epigenetic and topological domains that are associated with distinct phases of the cell cycle that may be altered in cancer initiation and progression, and (3) the requirement for mitotic bookmarking to maintain intranuclear localization of transcriptional regulatory machinery to reinforce cell identity throughout the cell cycle to prevent malignant transformation.
Collapse
Affiliation(s)
- Mohammed El Dika
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Andrew J. Fritz
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Rabail H. Toor
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | | | - Stephen J. Foley
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Rahim Ullah
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Daijing Nie
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Bodhisattwa Banerjee
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Dorcas Lohese
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Karen C. Glass
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Pharmacology, Burlington, VT 05405
| | - Seth Frietze
- University of Vermont, College of Nursing and Health Sciences, Burlington, VT 05405
| | - Prachi N. Ghule
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Jessica L. Heath
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405,University of Vermont, Larner College of Medicine, Department of Pediatrics, Burlington, VT 05405
| | - Anthony N. Imbalzano
- UMass Chan Medical School, Department of Biochemistry and Molecular Biotechnology, Worcester, MA 01605
| | - Andre van Wijnen
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Jonathan Gordon
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Jane B. Lian
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Janet L. Stein
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | - Gary S. Stein
- University of Vermont, UVM Cancer Center, Larner College of Medicine, Department of Biochemistry, Burlington, VT 05405
| | | |
Collapse
|
12
|
The Cyclin Cln1 Controls Polyploid Titan Cell Formation following a Stress-Induced G 2 Arrest in Cryptococcus. mBio 2021; 12:e0250921. [PMID: 34634930 PMCID: PMC8510536 DOI: 10.1128/mbio.02509-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The pathogenic yeast Cryptococcus neoformans produces polyploid titan cells in response to the host lung environment that are critical for host adaptation and subsequent disease. We analyzed the in vivo and in vitro cell cycles to identify key aspects of the C. neoformans cell cycle that are important for the formation of titan cells. We identified unbudded 2C cells, referred to as a G2 arrest, produced both in vivo and in vitro in response to various stresses. Deletion of the nonessential cyclin Cln1 resulted in overproduction of titan cells in vivo and transient morphology defects upon release from stationary phase in vitro. Using a copper-repressible promoter PCTR4-CLN1 strain and a two-step in vitro titan cell formation assay, our in vitro studies revealed Cln1 functions after the G2 arrest. These studies highlight unique cell cycle alterations in C. neoformans that ultimately promote genomic diversity and virulence in this important fungal pathogen.
Collapse
|
13
|
Roubinet C, White IJ, Baum B. Asymmetric nuclear division in neural stem cells generates sibling nuclei that differ in size, envelope composition, and chromatin organization. Curr Biol 2021; 31:3973-3983.e4. [PMID: 34297912 PMCID: PMC8491657 DOI: 10.1016/j.cub.2021.06.063] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 05/12/2021] [Accepted: 06/23/2021] [Indexed: 01/08/2023]
Abstract
Although nuclei are the defining features of eukaryotes, we still do not fully understand how the nuclear compartment is duplicated and partitioned during division. This is especially the case for organisms that do not completely disassemble their nuclear envelope upon entry into mitosis. In studying this process in Drosophila neural stem cells, which undergo asymmetric divisions, we find that the nuclear compartment boundary persists during mitosis thanks to the maintenance of a supporting nuclear lamina. This mitotic nuclear envelope is then asymmetrically remodeled and partitioned to give rise to two daughter nuclei that differ in envelope composition and exhibit a >30-fold difference in volume. The striking difference in nuclear size was found to depend on two consecutive processes: asymmetric nuclear envelope resealing at mitotic exit at sites defined by the central spindle, and differential nuclear growth that appears to depend on the available local reservoir of ER/nuclear membranes, which is asymmetrically partitioned between the two daughter cells. Importantly, these asymmetries in size and composition of the daughter nuclei, and the associated asymmetries in chromatin organization, all become apparent long before the cortical release and the nuclear import of cell fates determinants. Thus, asymmetric nuclear remodeling during stem cell divisions may contribute to the generation of cellular diversity by initiating distinct transcriptional programs in sibling nuclei that contribute to later changes in daughter cell identity and fate.
Collapse
Affiliation(s)
- Chantal Roubinet
- MRC Laboratory for Molecular Biology, University College London, London, UK; MRC Laboratory of Molecular Cell Biology, Cambridge, UK.
| | - Ian J White
- MRC Laboratory for Molecular Biology, University College London, London, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Biology, University College London, London, UK; Institute for the Physics of Living Systems, University College London, London, UK; MRC Laboratory of Molecular Cell Biology, Cambridge, UK.
| |
Collapse
|
14
|
Lagunas-Rangel FA, Yee J, Bermúdez-Cruz RM. An update on cell division of Giardia duodenalis trophozoites. Microbiol Res 2021; 250:126807. [PMID: 34130067 DOI: 10.1016/j.micres.2021.126807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/08/2021] [Accepted: 06/08/2021] [Indexed: 11/30/2022]
Abstract
Giardia duodenalis is a flagellated protozoan that is responsible for many cases of diarrheal disease worldwide and is characterized by its great divergence from the model organisms commonly used in studies of basic cellular processes. The life cycle of Giardia involves an infectious cyst form and a proliferative and mobile trophozoite form. Each Giardia trophozoite has two nuclei and a complex microtubule cytoskeleton that consists of eight flagellar axonemes, basal bodies, the adhesive disc, the funis and the median body. Since the success of Giardia infecting other organisms depends on its ability to divide and proliferate efficiently, Giardia must coordinate its cell division to ensure the duplication and partitioning of both nuclei and the multiple cytoskeletal structures. The purpose of this review is to summarize current knowledge about cell division and its regulation in this protist.
Collapse
Affiliation(s)
- Francisco Alejandro Lagunas-Rangel
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico; Department of Neuroscience, Functional Pharmacology, Uppsala University, Uppsala, Sweden
| | - Janet Yee
- Department of Biology, Biochemistry and Molecular Biology Program, Trent University, Peterborough, ON, Canada
| | - Rosa María Bermúdez-Cruz
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Mexico City, Mexico.
| |
Collapse
|
15
|
Ikui AE, Ueki N, Pecani K, Cross FR. Control of pre-replicative complex during the division cycle in Chlamydomonas reinhardtii. PLoS Genet 2021; 17:e1009471. [PMID: 33909603 PMCID: PMC8081180 DOI: 10.1371/journal.pgen.1009471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 03/07/2021] [Indexed: 12/31/2022] Open
Abstract
DNA replication is fundamental to all living organisms. In yeast and animals, it is triggered by an assembly of pre-replicative complex including ORC, CDC6 and MCMs. Cyclin Dependent Kinase (CDK) regulates both assembly and firing of the pre-replicative complex. We tested temperature-sensitive mutants blocking Chlamydomonas DNA replication. The mutants were partially or completely defective in DNA replication and did not produce mitotic spindles. After a long G1, wild type Chlamydomonas cells enter a division phase when it undergoes multiple rapid synchronous divisions ('multiple fission'). Using tagged transgenic strains, we found that MCM4 and MCM6 were localized to the nucleus throughout the entire multiple fission division cycle, except for transient cytoplasmic localization during each mitosis. Chlamydomonas CDC6 was transiently localized in nucleus in early division cycles. CDC6 protein levels were very low, probably due to proteasomal degradation. CDC6 levels were severely reduced by inactivation of CDKA1 (CDK1 ortholog) but not the plant-specific CDKB1. Proteasome inhibition did not detectably increase CDC6 levels in the cdka1 mutant, suggesting that CDKA1 might upregulate CDC6 at the transcriptional level. All of the DNA replication proteins tested were essentially undetectable until late G1. They accumulated specifically during multiple fission and then were degraded as cells completed their terminal divisions. We speculate that loading of origins with the MCM helicase may not occur until the end of the long G1, unlike in the budding yeast system. We also developed a simple assay for salt-resistant chromatin binding of MCM4, and found that tight MCM4 loading was dependent on ORC1, CDC6 and MCM6, but not on RNR1 or CDKB1. These results provide a microbial framework for approaching replication control in the plant kingdom.
Collapse
Affiliation(s)
- Amy E. Ikui
- Department of Biology, Brooklyn College, The City University of New York, New York City, New York, United States of America
- * E-mail: (AEI); (FRC)
| | - Noriko Ueki
- Department of Biology, Brooklyn College, The City University of New York, New York City, New York, United States of America
| | - Kresti Pecani
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York City, New York, United States of America
| | - Frederick R. Cross
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York City, New York, United States of America
- * E-mail: (AEI); (FRC)
| |
Collapse
|
16
|
Santos Júnior ADCMD, Melo RM, Ferreira BVG, Pontes AH, Lima CMRD, Fontes W, Sousa MVD, Lima BDD, Ricart CAO. Quantitative proteomics and phosphoproteomics of Trypanosoma cruzi epimastigote cell cycle. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140619. [PMID: 33561577 DOI: 10.1016/j.bbapap.2021.140619] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 01/19/2021] [Accepted: 02/01/2021] [Indexed: 11/30/2022]
Abstract
The protozoan Trypanosoma cruzi is the causative agent of the neglected infectious illness Chagas disease. During its life cycle it differentiates into replicative and non-replicative life stages. So far, T. cruzi cell division has been investigated by transcriptomics but not by proteomics approaches. Here we show the first quantitative proteome analysis of T. cruzi cell division. T. cruzi epimastigote cultures were subject to synchronization with hydroxyurea and harvested at different time points. Analysis by flow cytometry, bright field and fluorescence microscopy indicated that samples collected at 0 h, 2 h, 6 h and 14 h overrepresented G1, G1-S, S and M cell cycle phases, respectively. After trypsin digestion of these samples, the resulting peptides were labelled with iTRAQ and subjected to LC-MS/MS. Also, iTRAQ-labelled phosphopeptides were enriched with TiO2 to access the phosphoproteome. Overall, 597 protein groups and 94 phosphopeptides presented regulation with the most remarkable variation in abundance at 6 h (S-phase). Comparison of our proteomic data to previous transcriptome-wise analysis of epimastigote cell cycle showed 16 sequence entries in common, with the highest mRNA/protein correlation observed in transcripts with peak abundance in G1-phase. Our data revealed regulated proteins and phosphopeptides which play important roles in the control of cell division in other organisms and some of them were previously detected in the nucleus or associated with T. cruzi chromatin.
Collapse
Affiliation(s)
- Agenor de Castro Moreira Dos Santos Júnior
- Laboratory Protein Chemistry and Biochemistry, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil; Laboratory of Gene Biology, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
| | - Reynaldo Magalhães Melo
- Laboratory Protein Chemistry and Biochemistry, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
| | | | - Arthur Henriques Pontes
- Laboratory Protein Chemistry and Biochemistry, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
| | | | - Wagner Fontes
- Laboratory Protein Chemistry and Biochemistry, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
| | - Marcelo Valle de Sousa
- Laboratory Protein Chemistry and Biochemistry, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
| | - Beatriz Dolabela de Lima
- Laboratory of Gene Biology, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil
| | - Carlos André Ornelas Ricart
- Laboratory Protein Chemistry and Biochemistry, Department of Cell Biology, University of Brasília, Brasília, DF, Brazil.
| |
Collapse
|
17
|
Drosophila female germline stem cells undergo mitosis without nuclear breakdown. Curr Biol 2021; 31:1450-1462.e3. [PMID: 33548191 DOI: 10.1016/j.cub.2021.01.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/18/2020] [Accepted: 01/11/2021] [Indexed: 02/02/2023]
Abstract
Stem cell homeostasis requires nuclear lamina (NL) integrity. In Drosophila germ cells, compromised NL integrity activates the ataxia telangiectasia and Rad3-related (ATR) and checkpoint kinase 2 (Chk2) checkpoint kinases, blocking germ cell differentiation and causing germline stem cell (GSC) loss. Checkpoint activation occurs upon loss of either the NL protein emerin or its partner barrier-to-autointegration factor, two proteins required for nuclear reassembly at the end of mitosis. Here, we examined how mitosis contributes to NL structural defects linked to checkpoint activation. These analyses led to the unexpected discovery that wild-type female GSCs utilize a non-canonical mode of mitosis, one that retains a permeable but intact nuclear envelope and NL. We show that the interphase NL is remodeled during mitosis for insertion of centrosomes that nucleate the mitotic spindle within the confines of the nucleus. We show that depletion or loss of NL components causes mitotic defects, including compromised chromosome segregation associated with altered centrosome positioning and structure. Further, in emerin mutant GSCs, centrosomes remain embedded in the interphase NL. Notably, these embedded centrosomes carry large amounts of pericentriolar material and nucleate astral microtubules, revealing a role for emerin in the regulation of centrosome structure. Epistasis studies demonstrate that defects in centrosome structure are upstream of checkpoint activation, suggesting that these centrosome defects might trigger checkpoint activation and GSC loss. Connections between NL proteins and centrosome function have implications for mechanisms associated with NL dysfunction in other stem cell populations, including NL-associated diseases, such as laminopathies.
Collapse
|
18
|
Dey G, Baum B. Nuclear envelope remodelling during mitosis. Curr Opin Cell Biol 2021; 70:67-74. [PMID: 33421755 PMCID: PMC8129912 DOI: 10.1016/j.ceb.2020.12.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022]
Abstract
The defining feature of the eukaryotic cell, the nucleus, is bounded by a double envelope. This envelope and the nuclear pores within it play a critical role in separating the genome from the cytoplasm. It also presents cells with a challenge. How are cells to remodel the nuclear compartment boundary during mitosis without compromising nuclear function? In the two billion years since the emergence of the first cells with a nucleus, eukaryotes have evolved a range of strategies to do this. At one extreme, the nucleus is disassembled upon entry into mitosis and then reassembled anew in the two daughter cells. At the other, cells maintain an intact nuclear compartment boundary throughout the division process. In this review, we discuss common features of the division process that underpin remodelling mechanisms, the topological challenges involved and speculate on the selective pressures that may drive the evolution of distinct modes of division.
Collapse
Affiliation(s)
- Gautam Dey
- Cell Biology and Biophysics, European Molecular Biology Laboratory, 69117, Heidelberg, Germany.
| | - Buzz Baum
- Lab of Molecular Biology, Cambridge, CB2 0QH, United Kingdom; Lab for Molecular Cell Biology, UCL, London, WC1E 6BT, United Kingdom.
| |
Collapse
|
19
|
Zhang J, Deng Y, Khoo BL. Fasting to enhance Cancer treatment in models: the next steps. J Biomed Sci 2020; 27:58. [PMID: 32370764 PMCID: PMC7201989 DOI: 10.1186/s12929-020-00651-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/22/2020] [Indexed: 02/06/2023] Open
Abstract
Short-term fasting (STF) is a technique to reduce nutrient intake for a specific period. Since metabolism plays a pivotal role in tumor progression, it can be hypothesized that STF can improve the efficacy of chemotherapy. Recent studies have demonstrated the efficacy of STF in cell and animal tumor models. However, large-scale clinical trials must be conducted to verify the safety and effectiveness of these diets. In this review, we re-examine the concept of how metabolism affects pathophysiological pathways. Next, we provided a comprehensive discussion of the specific mechanisms of STF on tumor progression, derived through studies carried out with tumor models. There are currently at least four active clinical trials on fasting and cancer treatment. Based on these studies, we highlight the potential caveats of fasting in clinical applications, including the onset of metabolic syndrome and other metabolic complications during chemotherapy, with a particular focus on the regulation of the epithelial to mesenchymal pathway and cancer heterogeneity. We further discuss the advantages and disadvantages of the current state-of-art tumor models for assessing the impact of STF on cancer treatment. Finally, we explored upcoming fasting strategies that could complement existing chemotherapy and immunotherapy strategies to enable personalized medicine. Overall, these studies have the potential for breakthroughs in cancer management.
Collapse
Affiliation(s)
- Jing Zhang
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Yanlin Deng
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Bee Luan Khoo
- Department of Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong.
| |
Collapse
|
20
|
Baskin L, Derpinghaus A, Cao M, Sinclair A, Li Y, Overland M, Cunha GR. Hot spots in fetal human penile and clitoral development. Differentiation 2019; 112:27-38. [PMID: 31874420 DOI: 10.1016/j.diff.2019.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 10/28/2019] [Accepted: 11/11/2019] [Indexed: 11/29/2022]
Abstract
To better understand how the human fetal penis and clitoris grows and remodels, we undertook an investigation to define active areas of cellular proliferation and programmed cell death spatially and temporally during development of human fetal external genitalia from the indifferent stage (8 weeks) to 18 weeks of gestation. Fifty normal human fetal penile and clitoral specimens were examined using macroscopic imaging, scanning electron microscopy and immunohistochemical localization for the cellular proliferation and apoptotic markers, Ki67 and Caspase-3, respectively. A number of hot spots of cellular proliferation characterized by Ki67 localization are present in the penis and clitoris especially early in development, most notably in the corporal body, glans, remodeling glanular urethra, the urethral plate, the roof of the urethral groove and the fully formed penile urethra. The 12-fold increase in penile length over 10 weeks of growth from 8 to 18 weeks of gestation based on Ki67 labelling appears to be driven by cellular proliferation in the corporal body and glans. Throughout all ages in both the developing penis and clitoris Ki67 labeling was consistently elevated in the ventral epidermis and ventral mesenchyme relative to the dorsal counterparts. This finding is consistent with the intense morphogenetic activity/remodeling in the ventral half of the genital tubercle in both sexes involving formation of the urethral/vestibular plates, canalization of the urethral/vestibular plates and fusion of the urethral folds to form the penile urethra. Areas of reduced or absent Ki67 staining include the urethral fold epithelium that fuses to form the penile tubular urethra. In contrast, the urethral fold mesenchyme is positive for Ki67. Apoptosis was rarely noted in the developing penis and clitoris; the only area of minimal Caspase-3 localization was in the epithelium of the ventral epithelial glanular channel remodeling.
Collapse
Affiliation(s)
- Laurence Baskin
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA.
| | - Amber Derpinghaus
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Mei Cao
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Adriane Sinclair
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Yi Li
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Maya Overland
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Gerald R Cunha
- Department of Urology, University of California, San Francisco, San Francisco, CA, USA; Division of Pediatric Urology, University of California San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| |
Collapse
|
21
|
Abstract
During my postdoc interview in June of 1998, I asked Günter why he was moving more towards the nucleus in his latest studies. He said, "Well Joe, that's where everything starts." By the end of the interview, I accepted the postdoc. He had a way of making everything sound so cool. Günter's progression was natural, since the endoplasmic reticulum and the nucleus are the only organelles that share the same membrane. The nuclear envelope extends into a double membrane system with nuclear pore complexes embedded in the pore membrane openings. Even while writing this review, I remember Günter stressing; it is the nuclear pore complex. Just saying nuclear pore doesn't encompass the full magnitude of its significance. The nuclear pore complex is one of the largest collection of proteins that fit together for an overall function: transport. This review will cover the Blobel lab contributions in the quest for the blueprint of the nuclear pore complex from isolation of the nuclear envelope and nuclear lamin to the ring structures.
Collapse
|
22
|
Wang JH, Li Y, Deng SL, Liu YX, Lian ZX, Yu K. Recent Research Advances in Mitosis during Mammalian Gametogenesis. Cells 2019; 8:cells8060567. [PMID: 31185583 PMCID: PMC6628140 DOI: 10.3390/cells8060567] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/02/2019] [Accepted: 06/06/2019] [Indexed: 12/13/2022] Open
Abstract
Mitosis is a highly sophisticated and well-regulated process during the development and differentiation of mammalian gametogenesis. The regulation of mitosis plays an essential role in keeping the formulation in oogenesis and gametogenesis. In the past few years, substantial research progress has been made by showing that cyclins/cyclin-dependent kinase (CDK) have roles in the regulation of meiosis. In addition, more functional signaling molecules have been discovered in mitosis. Growing evidence has also indicated that miRNAs influence cell cycling. In this review, we focus on specific genes, cyclins/Cdk, signaling pathways/molecules, and miRNAs to discuss the latest achievements in understanding their roles in mitosis during gametogenesis. Further elucidation of mitosis during gametogenesis may facilitate delineating all processes of mammalian reproduction and the development of disease treatments.
Collapse
Affiliation(s)
- Jia-Hao Wang
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
| | - Yan Li
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
| | - Shou-Long Deng
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Yi-Xun Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Zheng-Xing Lian
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
| | - Kun Yu
- Beijing Key Laboratory for Animal Genetic Improvement, National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
| |
Collapse
|
23
|
Abstract
The emergence of eukaryotes from ancient prokaryotic lineages embodied a remarkable increase in cellular complexity. While prokaryotes operate simple systems to connect DNA to the segregation machinery during cell division, eukaryotes use a highly complex protein assembly known as the kinetochore. Although conceptually similar, prokaryotic segregation systems and the eukaryotic kinetochore are not homologous. Here we investigate the origins of the kinetochore before the last eukaryotic common ancestor (LECA) using phylogenetic trees, sensitive profile-versus-profile homology detection, and structural comparisons of its protein components. We show that LECA's kinetochore proteins share deep evolutionary histories with proteins involved in a few prokaryotic systems and a multitude of eukaryotic processes, including ubiquitination, transcription, and flagellar and vesicular transport systems. We find that gene duplications played a major role in shaping the kinetochore; more than half of LECA's kinetochore proteins have other kinetochore proteins as closest homologs. Some of these have no detectable homology to any other eukaryotic protein, suggesting that they arose as kinetochore-specific folds before LECA. We propose that the primordial kinetochore evolved from proteins involved in various (pre)eukaryotic systems as well as evolutionarily novel folds, after which a subset duplicated to give rise to the complex kinetochore of LECA.
Collapse
|
24
|
Aspergillus nidulans in the post-genomic era: a top-model filamentous fungus for the study of signaling and homeostasis mechanisms. Int Microbiol 2019; 23:5-22. [DOI: 10.1007/s10123-019-00064-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/30/2019] [Accepted: 02/04/2019] [Indexed: 02/07/2023]
|
25
|
Varshney N, Som S, Chatterjee S, Sridhar S, Bhattacharyya D, Paul R, Sanyal K. Spatio-temporal regulation of nuclear division by Aurora B kinase Ipl1 in Cryptococcus neoformans. PLoS Genet 2019; 15:e1007959. [PMID: 30763303 PMCID: PMC6392335 DOI: 10.1371/journal.pgen.1007959] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 02/27/2019] [Accepted: 01/11/2019] [Indexed: 11/29/2022] Open
Abstract
The nuclear division takes place in the daughter cell in the basidiomycetous budding yeast Cryptococcus neoformans. Unclustered kinetochores gradually cluster and the nucleus moves to the daughter bud as cells enter mitosis. Here, we show that the evolutionarily conserved Aurora B kinase Ipl1 localizes to the nucleus upon the breakdown of the nuclear envelope during mitosis in C. neoformans. Ipl1 is shown to be required for timely breakdown of the nuclear envelope as well. Ipl1 is essential for viability and regulates structural integrity of microtubules. The compromised stability of cytoplasmic microtubules upon Ipl1 depletion results in a significant delay in kinetochore clustering and nuclear migration. By generating an in silico model of mitosis, we previously proposed that cytoplasmic microtubules and cortical dyneins promote atypical nuclear division in C. neoformans. Improving the previous in silico model by introducing additional parameters, here we predict that an effective cortical bias generated by cytosolic Bim1 and dynein regulates dynamics of kinetochore clustering and nuclear migration. Indeed, in vivo alterations of Bim1 or dynein cellular levels delay nuclear migration. Results from in silico model and localization dynamics by live cell imaging suggests that Ipl1 spatio-temporally influences Bim1 or/and dynein activity along with microtubule stability to ensure timely onset of nuclear division. Together, we propose that the timely breakdown of the nuclear envelope by Ipl1 allows its own nuclear entry that helps in spatio-temporal regulation of nuclear division during semi-open mitosis in C. neoformans. Unlike the model ascomycetous budding yeast Saccharomyces cerevisiae, microtubule organizing centers (MTOCs) coalesce to form the spindle pole body (SPB) in C. neoformans. This process also ensures unclustered kinetochores to gradually cluster in this organism. As C. neoformans cells enter mitosis, the nuclear envelope ruptures and the nucleus eventually moves to the daughter bud before division. Here, we combine cell and systems biology techniques to understand the key determinants of nuclear division in C. neoformans. We show that the evolutionarily conserved Aurora B kinase Ipl1 enters the nucleus during the mitotic phase as cells undergo semi-open mitosis. Ipl1 regulates dynamics of cytoplasmic microtubules, cytosolic proteins such as Bim1 and dynein-mediated cortical forces and integrity of the nuclear envelope to ensure timely kinetochore clustering and nuclear division in this medically relevant human pathogenic budding yeast.
Collapse
Affiliation(s)
- Neha Varshney
- Molecular Mycology Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Subhendu Som
- Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata, India
| | - Saptarshi Chatterjee
- Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata, India
| | - Shreyas Sridhar
- Molecular Mycology Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Dibyendu Bhattacharyya
- Tata Memorial Centre, Advanced Centre for Treatment Research and Education in Cancer, Kharghar, Navi Mumbai, India
| | - Raja Paul
- Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata, India
- * E-mail: (RP); (KS)
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
- * E-mail: (RP); (KS)
| |
Collapse
|
26
|
Mela AP, Momany M. Internuclear diffusion of histone H1 within cellular compartments of Aspergillus nidulans. PLoS One 2018; 13:e0201828. [PMID: 30114268 PMCID: PMC6095493 DOI: 10.1371/journal.pone.0201828] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 07/23/2018] [Indexed: 11/18/2022] Open
Abstract
Histone H1 is an evolutionarily conserved linker histone protein that functions in arranging and stabilizing chromatin structure and is frequently fused to a fluorescent protein to track nuclei in live cells. In time-lapse analyses, we observed stochastic exchange of photoactivated Dendra2-histone H1 protein between nuclei within the same cellular compartment. We also observed exchange of histones between genetically distinct nuclei in a heterokaryon derived from fusion of strains carrying histone H1-RFP or H1-GFP. Subsequent analysis of the resulting uninucleate conidia containing both RFP- and GFP-labeled histone H1 proteins showed only parental genotypes, ruling out genetic recombination and diploidization. These data together suggest that the linker histone H1 protein can diffuse between non-daughter nuclei in the filamentous fungus Aspergillus nidulans.
Collapse
Affiliation(s)
- Alexander P. Mela
- Fungal Biology Group and Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America
| | - Michelle Momany
- Fungal Biology Group and Department of Plant Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
| |
Collapse
|
27
|
White MW, Suvorova ES. Apicomplexa Cell Cycles: Something Old, Borrowed, Lost, and New. Trends Parasitol 2018; 34:759-771. [PMID: 30078701 PMCID: PMC6157590 DOI: 10.1016/j.pt.2018.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 02/04/2023]
Abstract
Increased parasite burden is linked to the severity of clinical disease caused by Apicomplexa parasites such as Toxoplasma gondii, Plasmodium spp, and Cryptosporidium. Pathogenesis of apicomplexan infections is greatly affected by the growth rate of the parasite asexual stages. This review discusses recent advances in deciphering the mitotic structures and cell cycle regulatory factors required by Apicomplexa parasites to replicate. As the molecular details become clearer, it is evident that the highly unconventional cell cycles of these parasites is a blending of many ancient and borrowed elements, which were then adapted to enable apicomplexan proliferation in a wide variety of different animal hosts.
Collapse
Affiliation(s)
- Michael W White
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Elena S Suvorova
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA.
| |
Collapse
|
28
|
Ito D, Bettencourt-Dias M. Centrosome Remodelling in Evolution. Cells 2018; 7:E71. [PMID: 29986477 PMCID: PMC6070874 DOI: 10.3390/cells7070071] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 06/27/2018] [Accepted: 07/04/2018] [Indexed: 11/16/2022] Open
Abstract
The centrosome is the major microtubule organizing centre (MTOC) in animal cells. The canonical centrosome is composed of two centrioles surrounded by a pericentriolar matrix (PCM). In contrast, yeasts and amoebozoa have lost centrioles and possess acentriolar centrosomes—called the spindle pole body (SPB) and the nucleus-associated body (NAB), respectively. Despite the difference in their structures, centriolar centrosomes and SPBs not only share components but also common biogenesis regulators. In this review, we focus on the SPB and speculate how its structures evolved from the ancestral centrosome. Phylogenetic distribution of molecular components suggests that yeasts gained specific SPB components upon loss of centrioles but maintained PCM components associated with the structure. It is possible that the PCM structure remained even after centrosome remodelling due to its indispensable function to nucleate microtubules. We propose that the yeast SPB has been formed by a step-wise process; (1) an SPB-like precursor structure appeared on the ancestral centriolar centrosome; (2) it interacted with the PCM and the nuclear envelope; and (3) it replaced the roles of centrioles. Acentriolar centrosomes should continue to be a great model to understand how centrosomes evolved and how centrosome biogenesis is regulated.
Collapse
Affiliation(s)
- Daisuke Ito
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
| | | |
Collapse
|
29
|
Pfeifer MA, Khang CH. A nuclear contortionist: the mitotic migration of Magnaporthe oryzae nuclei during plant infection. Mycology 2018; 9:202-210. [PMID: 30181926 PMCID: PMC6115875 DOI: 10.1080/21501203.2018.1482966] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/25/2018] [Indexed: 01/22/2023] Open
Abstract
Magnaporthe oryzae is a filamentous fungus, which causes significant destruction to cereal crops worldwide. To infect plant cells, the fungus develops specialised constricted structures such as the penetration peg and the invasive hyphal peg. Live-cell imaging of M. oryzae during plant infection reveals that nuclear migration occurs during intermediate mitosis, in which the nuclear envelope neither completely disassembles nor remains entirely intact. Remarkably, in M. oryzae, mitotic nuclei show incredible malleability while undergoing confined migration through the constricted penetration and invasive hyphal pegs. Here, we review early events in plant infection, discuss intermediate mitosis, and summarise current knowledge of intermediate mitotic nuclear migration in M. oryzae.
Collapse
Affiliation(s)
- Mariel A Pfeifer
- Department of Plant Biology, University of Georgia, Athens, GA30602, USA
| | - Chang Hyun Khang
- Department of Plant Biology, University of Georgia, Athens, GA30602, USA
| |
Collapse
|
30
|
Bazzaz AA, Bukhari FO, Mohammed AI, Chelebi NA. Anin vitroassessment of growth promoting activity of a synthetic basic fibroblast growth factor (b-FGF) using Rama-27 cell line. JOURNAL OF TAIBAH UNIVERSITY FOR SCIENCE 2018. [DOI: 10.1016/j.jtusci.2012.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Ayoub A. Bazzaz
- Department of Biology, Faculty of Science, University of Taibah, Al-Madinah Al-Munawarah, Kingdom of Saudi Arabia
| | - Fatin O. Bukhari
- Department of Biology, Faculty of Science, University of Taibah, Al-Madinah Al-Munawarah, Kingdom of Saudi Arabia
| | - Amal I. Mohammed
- Department of Zoology, Faculty of Science, University of Ain Shams, Cairo, Egypt
| | - Noorhan A. Chelebi
- Department of Biochemistry, Institute of Life Sciences, University of Liverpool, Liverpool L69 3ZB, UK
| |
Collapse
|
31
|
Suresh S, Markossian S, Osmani AH, Osmani SA. Mitotic nuclear pore complex segregation involves Nup2 in Aspergillus nidulans. J Cell Biol 2017; 216:2813-2826. [PMID: 28747316 PMCID: PMC5584150 DOI: 10.1083/jcb.201610019] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 05/11/2017] [Accepted: 07/06/2017] [Indexed: 01/20/2023] Open
Abstract
Transport through nuclear pore complexes (NPCs) during interphase is facilitated by the nucleoporin Nup2 via its importin α- and Ran-binding domains. However, Aspergillus nidulans and vertebrate Nup2 also locate to chromatin during mitosis, suggestive of mitotic functions. In this study, we report that Nup2 is required for mitotic NPC inheritance in A. nidulans Interestingly, the role of Nup2 during mitotic NPC segregation is independent of its importin α- and Ran-binding domains but relies on a central targeting domain that is necessary for localization and viability. To test whether mitotic chromatin-associated Nup2 might function to bridge NPCs with chromatin during segregation, we provided an artificial link between NPCs and chromatin via Nup133 and histone H1. Using this approach, we bypassed the requirement of Nup2 for NPC segregation. This indicates that A. nidulans cells ensure accurate mitotic NPC segregation to daughter nuclei by linking mitotic DNA and NPC segregation via the mitotic specific chromatin association of Nup2.
Collapse
Affiliation(s)
- Subbulakshmi Suresh
- Department of Molecular Genetics, The Ohio State University, Columbus, OH.,Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY
| | - Sarine Markossian
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
| | - Aysha H Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
| | - Stephen A Osmani
- Department of Molecular Genetics, The Ohio State University, Columbus, OH
| |
Collapse
|
32
|
Abstract
All cells must accurately replicate DNA and partition it to daughter cells. The basic cell cycle machinery is highly conserved among eukaryotes. Most of the mechanisms that control the cell cycle were worked out in fungal cells, taking advantage of their powerful genetics and rapid duplication times. Here we describe the cell cycles of the unicellular budding yeast Saccharomyces cerevisiae and the multicellular filamentous fungus Aspergillus nidulans. We compare and contrast morphological landmarks of G1, S, G2, and M phases, molecular mechanisms that drive cell cycle progression, and checkpoints in these model unicellular and multicellular fungal systems.
Collapse
|
33
|
van Hooff JJ, Tromer E, van Wijk LM, Snel B, Kops GJ. Evolutionary dynamics of the kinetochore network in eukaryotes as revealed by comparative genomics. EMBO Rep 2017. [PMID: 28642229 PMCID: PMC5579357 DOI: 10.15252/embr.201744102] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During eukaryotic cell division, the sister chromatids of duplicated chromosomes are pulled apart by microtubules, which connect via kinetochores. The kinetochore is a multiprotein structure that links centromeres to microtubules, and that emits molecular signals in order to safeguard the equal distribution of duplicated chromosomes over daughter cells. Although microtubule‐mediated chromosome segregation is evolutionary conserved, kinetochore compositions seem to have diverged. To systematically inventory kinetochore diversity and to reconstruct its evolution, we determined orthologs of 70 kinetochore proteins in 90 phylogenetically diverse eukaryotes. The resulting ortholog sets imply that the last eukaryotic common ancestor (LECA) possessed a complex kinetochore and highlight that current‐day kinetochores differ substantially. These kinetochores diverged through gene loss, duplication, and, less frequently, invention and displacement. Various kinetochore components co‐evolved with one another, albeit in different manners. These co‐evolutionary patterns improve our understanding of kinetochore function and evolution, which we illustrated with the RZZ complex, TRIP13, the MCC, and some nuclear pore proteins. The extensive diversity of kinetochore compositions in eukaryotes poses numerous questions regarding evolutionary flexibility of essential cellular functions.
Collapse
Affiliation(s)
- Jolien Je van Hooff
- Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands.,Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands.,Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Eelco Tromer
- Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands.,Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | - Leny M van Wijk
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, Utrecht, The Netherlands
| | - Geert Jpl Kops
- Hubrecht Institute - KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands .,Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands.,Cancer Genomics Netherlands, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
34
|
van Hooff JJE, Snel B, Kops GJPL. Unique Phylogenetic Distributions of the Ska and Dam1 Complexes Support Functional Analogy and Suggest Multiple Parallel Displacements of Ska by Dam1. Genome Biol Evol 2017; 9:1295-1303. [PMID: 28472331 PMCID: PMC5439489 DOI: 10.1093/gbe/evx088] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2017] [Indexed: 12/27/2022] Open
Abstract
Faithful chromosome segregation relies on kinetochores, the large protein complexes that connect chromatin to spindle microtubules. Although human and yeast kinetochores are largely homologous, they track microtubules with the unrelated protein complexes Ska (Ska-C, human) and Dam1 (Dam1-C, yeast). We here uncovered that Ska-C and Dam1-C are both widespread among eukaryotes, but in an exceptionally inverse manner, supporting their functional analogy. Within the complexes, all Ska-C and various Dam1-C subunits are ancient paralogs, showing that gene duplication shaped these complexes. We examined various evolutionary scenarios to explain the nearly mutually exclusive patterns of Ska-C and Dam1-C in present-day species. We propose that Ska-C was present in the last eukaryotic common ancestor, that subsequently Dam1-C displaced Ska-C in an early fungus and was horizontally transferred to diverse non-fungal lineages, displacing Ska-C in these lineages too.
Collapse
Affiliation(s)
- Jolien J. E. van Hooff
- Hubrecht Institute – KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, The Netherlands
- Molecular Cancer Research, University Medical Center Utrecht, The Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, Department of Biology, Science Faculty, Utrecht University, The Netherlands
| | - Geert J. P. L. Kops
- Hubrecht Institute – KNAW (Royal Netherlands Academy of Arts and Sciences), Utrecht, The Netherlands
- Molecular Cancer Research, University Medical Center Utrecht, The Netherlands
- Cancer Genomics Netherlands, University Medical Center Utrecht, The Netherlands
| |
Collapse
|
35
|
Bailon-Moscoso N, Cevallos-Solorzano G, Romero-Benavides JC, Orellana MIR. Natural Compounds as Modulators of Cell Cycle Arrest: Application for Anticancer Chemotherapies. Curr Genomics 2017; 18:106-131. [PMID: 28367072 PMCID: PMC5345333 DOI: 10.2174/1389202917666160808125645] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/13/2015] [Accepted: 11/20/2015] [Indexed: 12/22/2022] Open
Abstract
Natural compounds from various plants, microorganisms and marine species play an important role in the discovery novel components that can be successfully used in numerous biomedical applications, including anticancer therapeutics. Since uncontrolled and rapid cell division is a hallmark of cancer, unraveling the molecular mechanisms underlying mitosis is key to understanding how various natural compounds might function as inhibitors of cell cycle progression. A number of natural compounds that inhibit the cell cycle arrest have proven effective for killing cancer cells in vitro, in vivo and in clinical settings. Significant advances that have been recently made in the understanding of molecular mechanisms underlying the cell cycle regulation using the chemotherapeutic agents is of great importance for improving the efficacy of targeted therapeutics and overcoming resistance to anticancer drugs, especially of natural origin, which inhibit the activities of cyclins and cyclin-dependent kinases, as well as other proteins and enzymes involved in proper regulation of cell cycle leading to controlled cell proliferation.
Collapse
|
36
|
Abstract
The number and nature of endosymbioses involving red algal endosymbionts are debated. Gene phylogenies have become the most popular tool to untangle this issue, but they deliver conflicting results. As gene and lineage sampling has increased, so have both the number of conflicting trees and the number of suggestions in the literature for multiple tertiary, and even quaternary, symbioses that might reconcile the tree conflicts. Independent lines of evidence that can address the issue are needed. Here we summarize the mechanism and machinery of protein import into complex red plastids. The process involves protein translocation machinery, known as SELMA, that arose once in evolution, that facilitates protein import across the second outermost of the four plastid membranes, and that is always targeted specifically to that membrane, regardless of where it is encoded today. It is widely accepted that the unity of protein import across the two membranes of primary plastids is strong evidence for their single cyanobacterial origin. Similarly, the unity of SELMA-dependent protein import across the second outermost plastid membrane constitutes strong evidence for the existence of a single red secondary endosymbiotic event at the common origin of all red complex plastids. We furthermore propose that the two outer membranes of red complex plastids are derived from host endoplasmic reticulum in the initial red secondary endosymbiotic event.
Collapse
Affiliation(s)
- Sven B Gould
- Institute of Molecular Evolution, Heinrich-Heine University, Düsseldorf, Germany.
| | - Uwe-G Maier
- Laboratory for Cell Biology and LOEWE Centre for Synthetic Microbiology (SYNMIKRO), Phillips University, Marburg, Germany
| | - William F Martin
- Institute of Molecular Evolution, Heinrich-Heine University, Düsseldorf, Germany
| |
Collapse
|
37
|
Labarrade F, Botto JM, Domloge N. CRM1 and chromosomal passenger complex component survivin are essential to normal mitosis progress and to preserve keratinocytes from mitotic abnormalities. Int J Cosmet Sci 2016; 38:452-61. [PMID: 26859314 DOI: 10.1111/ics.12311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/04/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Human epidermis provides the body a barrier against environmental assaults. To assume this function, the epidermis needs the renewal of keratinocytes allowed by constant mitosis, which replace the exfoliating corneocytes. Keratinocyte stem cells (KSCs) located in the basal epidermis are mitotically active, self-renewing and govern the epithelial stratification by producing renewed source of keratinocytes. Protein complex such as the chromosomal passenger complex (CPC) allows the correct development of this process. The CPC is composed of four members: INCENP, survivin, borealin and aurora kinase B, and the disruption of the CPC during cell division induces mitotic spindle defects and improper repartition of chromosomes. The aim of our study was to investigate the implication of CRM1 and survivin in the progress of mitosis in skin keratinocytes. METHODS Cultured human keratinocytes and skin biopsies were used in this study. KSCs-enriched population of keratinocytes was isolated from total keratinocytes by differential attachment to a type IV collagen matrix. Survivin and CRM1 expression levels were assessed by immunofluorescence and immunoblotting. Specific siRNAs for each CPC member and for CRM1 were used to determine the relationship between these proteins. Survivin-specific siRNA was used to induce the apparition of mitotic abnormalities in cultured keratinocytes. RESULTS We demonstrated the ability of our compound 'IV08.009' to modulate the expression level of survivin and CRM1 in keratinocytes and in skin biopsies. We observed that members of the CPC are interdependent: siRNA-induced inhibition of one component caused a decrease in the expression of all other CPC members. Downregulation of survivin or CRM1 induced mitotic abnormalities in keratinocytes. However, decreased number of mitotic abnormalities was observed in keratinocytes after 'IV08.009' application. CONCLUSION Basal keratinocytes may divide frequently during skin lifespan, and signs of deterioration could appear such as loss of protein factors required for correct mitosis. Our findings suggest that mitotic abnormalities can be prevented by the modulation of CRM1 and survivin. We demonstrated the ability of compound 'IV08.009' to efficiently protect cultured keratinocytes from mitotic abnormalities.
Collapse
Affiliation(s)
- F Labarrade
- Ashland Specialty Ingredients, Vincience Global Skin Research Center, 655, route du Pin Montard, 06904 Sophia Antipolis, France
| | - J-M Botto
- Ashland Specialty Ingredients, Vincience Global Skin Research Center, 655, route du Pin Montard, 06904 Sophia Antipolis, France.
| | - N Domloge
- Ashland Specialty Ingredients, Vincience Global Skin Research Center, 655, route du Pin Montard, 06904 Sophia Antipolis, France
| |
Collapse
|
38
|
Jones K, Jenkinson CB, Borges Araújo M, Zhu J, Kim RY, Kim DW, Khang CH. Mitotic stopwatch for the blast fungus Magnaporthe oryzae during invasion of rice cells. Fungal Genet Biol 2016; 93:46-9. [PMID: 27321562 DOI: 10.1016/j.fgb.2016.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 11/29/2022]
Abstract
To study nuclear dynamics of Magnaporthe oryzae, we developed a novel mitotic reporter strain with GFP-NLS (localized in nuclei during interphase but in the cytoplasm during mitosis) and H1-tdTomato (localized in nuclei throughout the cell cycle). Time-lapse confocal microscopy of the reporter strain during host cell invasion provided several new insights into nuclear division and migration in M. oryzae: (i) mitosis lasts about 5min; (ii) mitosis is semi-closed; (iii) septal pores are closed during mitosis; and (iv) a nucleus exhibits extreme constriction (approximately from 2μm to 0.5μm), elongation (over 5μm), and long migration (over 16μm). Our observations raise new questions about mechanisms controlling the mitotic dynamics, and the answers to these questions may result in new means to prevent fungal proliferation without negatively affecting the host cell cycle.
Collapse
Affiliation(s)
- Kiersun Jones
- Department of Plant Biology, University of Georgia, Athens 30602, USA
| | - Cory B Jenkinson
- Department of Plant Biology, University of Georgia, Athens 30602, USA
| | | | - Jie Zhu
- Department of Plant Biology, University of Georgia, Athens 30602, USA
| | - Rebecca Y Kim
- Department of Plant Biology, University of Georgia, Athens 30602, USA
| | - Dong Won Kim
- Department of Plant Biology, University of Georgia, Athens 30602, USA
| | - Chang Hyun Khang
- Department of Plant Biology, University of Georgia, Athens 30602, USA.
| |
Collapse
|
39
|
miR-30a can inhibit DNA replication by targeting RPA1 thus slowing cancer cell proliferation. Biochem J 2016; 473:2131-9. [PMID: 27208176 DOI: 10.1042/bcj20160177] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 05/17/2016] [Indexed: 02/04/2023]
Abstract
Cell proliferation was inhibited following forced over-expression of miR-30a in the ovary cancer cell line A2780DX5 and the gastric cancer cell line SGC7901R. Interestingly, miR-30a targets the DNA replication protein RPA1, hinders the replication of DNA and induces DNA fragmentation. Furthermore, ataxia telangiectasia mutated (ATM) and checkpoint kinase 2 (CHK2) were phosphorylated after DNA damage, which induced p53 expression, thus triggering the S-phase checkpoint, arresting cell cycle progression and ultimately initiating cancer cell apoptosis. Therefore, forced miR-30a over-expression in cancer cells can be a potential way to inhibit tumour development.
Collapse
|
40
|
Vlaardingerbroek I, Beerens B, Rose L, Fokkens L, Cornelissen BJC, Rep M. Exchange of core chromosomes and horizontal transfer of lineage-specific chromosomes in Fusarium oxysporum. Environ Microbiol 2016; 18:3702-3713. [PMID: 26941045 DOI: 10.1111/1462-2920.13281] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 02/22/2016] [Indexed: 01/09/2023]
Abstract
Horizontal transfer of supernumerary or lineage-specific (LS) chromosomes has been described in a number of plant pathogenic filamentous fungi. So far it was not known whether transfer is restricted to chromosomes of certain size or properties, or whether 'core' chromosomes can also undergo horizontal transfer. We combined a directed and a non-biased approach to determine whether such restrictions exist. Selection genes were integrated into the genome of a strain of Fusarium oxysporum pathogenic on tomato, either targeted to specific chromosomes by homologous recombination or integrated randomly into the genome. By testing these strains for transfer of the marker to another strain we could confirm transfer of a previously described mobile pathogenicity chromosome. Surprisingly, we also identified strains in which (parts of) core chromosomes were transferred. Whole genome sequencing revealed that this was accompanied by the loss of the homologous region from the recipient strain. Remarkably, transfer of the mobile pathogenicity chromosome always accompanied this exchange of core chromosomes.
Collapse
Affiliation(s)
| | - Bas Beerens
- Molecular Plant Pathology, University of Amsterdam, Amsterdam, The Netherlands
| | - Laura Rose
- Molecular Plant Pathology, University of Amsterdam, Amsterdam, The Netherlands
| | - Like Fokkens
- Molecular Plant Pathology, University of Amsterdam, Amsterdam, The Netherlands
| | - Ben J C Cornelissen
- Molecular Plant Pathology, University of Amsterdam, Amsterdam, The Netherlands
| | - Martijn Rep
- Molecular Plant Pathology, University of Amsterdam, Amsterdam, The Netherlands
| |
Collapse
|
41
|
Abstract
Nuclear pore complexes (NPCs) are indispensable for cell function and are at the center of several human diseases. NPCs provide access to the nucleus and regulate the transport of proteins and RNA across the nuclear envelope. They are aqueous channels generated from a complex network of evolutionarily conserved proteins known as nucleporins. In this Cell Science at a Glance article and the accompanying poster, we discuss how transport between the nucleoplasm and the cytoplasm is regulated, what we currently know about the structure of individual nucleoporins and the assembled NPC, and how the cell regulates assembly and disassembly of such a massive structure. Our aim is to provide a general overview on what we currently know about the nuclear pore and point out directions of research this area is heading to.
Collapse
|
42
|
Morano KA. Groupthink: chromosomal clustering during transcriptional memory. MICROBIAL CELL 2015; 2:454-457. [PMID: 28357270 PMCID: PMC5354603 DOI: 10.15698/mic2015.12.244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- Kevin A Morano
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, TX 77030 USA
| |
Collapse
|
43
|
Complex Commingling: Nucleoporins and the Spindle Assembly Checkpoint. Cells 2015; 4:706-25. [PMID: 26540075 PMCID: PMC4695854 DOI: 10.3390/cells4040706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/12/2015] [Accepted: 10/28/2015] [Indexed: 12/14/2022] Open
Abstract
The segregation of the chromosomes during mitosis is an important process, in which the replicated DNA content is properly allocated into two daughter cells. To ensure their genomic integrity, cells present an essential surveillance mechanism known as the spindle assembly checkpoint (SAC), which monitors the bipolar attachment of the mitotic spindle to chromosomes to prevent errors that would result in chromosome mis-segregation and aneuploidy. Multiple components of the nuclear pore complex (NPC), a gigantic protein complex that forms a channel through the nuclear envelope to allow nucleocytoplasmic exchange of macromolecules, were shown to be critical for faithful cell division and implicated in the regulation of different steps of the mitotic process, including kinetochore and spindle assembly as well as the SAC. In this review, we will describe current knowledge about the interconnection between the NPC and the SAC in an evolutional perspective, which primarily relies on the two mitotic checkpoint regulators, Mad1 and Mad2. We will further discuss the role of NPC constituents, the nucleoporins, in kinetochore and spindle assembly and the formation of the mitotic checkpoint complex during mitosis and interphase.
Collapse
|
44
|
The Inner Nuclear Membrane Protein Src1 Is Required for Stable Post-Mitotic Progression into G1 in Aspergillus nidulans. PLoS One 2015; 10:e0132489. [PMID: 26147902 PMCID: PMC4492595 DOI: 10.1371/journal.pone.0132489] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/15/2015] [Indexed: 01/13/2023] Open
Abstract
How membranes and associated proteins of the nuclear envelope (NE) are assembled specifically and inclusively around segregated genomes during exit from mitosis is incompletely understood. Inner nuclear membrane (INM) proteins play key roles by providing links between DNA and the NE. In this study we have investigated the highly conserved INM protein Src1 in Aspergillus nidulans and have uncovered a novel cell cycle response during post mitotic formation of G1 nuclei. Live cell imaging indicates Src1 could have roles during mitotic exit as it preferentially locates to the NE abscission points during nucleokinesis and to the NE surrounding forming daughter G1 nuclei. Deletion analysis further supported this idea revealing that although Src1 is not required for interphase progression or mitosis it is required for stable post-mitotic G1 nuclear formation. This conclusion is based upon the observation that in the absence of Src1 newly formed G1 nuclei are structurally unstable and immediately undergo architectural modifications typical of mitosis. These changes include NPC modifications that stop nuclear transport as well as disassembly of nucleoli. More intriguingly, the newly generated G1 nuclei then cycle between mitotic- and interphase-like states. The findings indicate that defects in post-mitotic G1 nuclear formation caused by lack of Src1 promote repeated failed attempts to generate stable G1 nuclei. To explain this unexpected phenotype we suggest a type of regulation that promotes repetition of defective cell cycle transitions rather than preventing progression past the defective cell cycle transition. We suggest the term “reboot regulation” to define this mode of cell cycle regulation. The findings are discussed in relationship to recent studies showing the Cdk1 master oscillator can entrain subservient oscillators that when uncoupled cause cell cycle transitions to be repeated.
Collapse
|
45
|
Gräf R, Batsios P, Meyer I. Evolution of centrosomes and the nuclear lamina: Amoebozoan assets. Eur J Cell Biol 2015; 94:249-56. [DOI: 10.1016/j.ejcb.2015.04.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/21/2015] [Accepted: 04/21/2015] [Indexed: 02/08/2023] Open
|
46
|
Fluorescence-Based Methods for the Study of Protein Localization, Interaction, and Dynamics in Filamentous Fungi. Fungal Biol 2015. [DOI: 10.1007/978-3-319-22437-4_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
47
|
Edgerton H, Paolillo V, Oakley BR. Spatial regulation of the spindle assembly checkpoint and anaphase-promoting complex in Aspergillus nidulans. Mol Microbiol 2014; 95:442-57. [PMID: 25417844 DOI: 10.1111/mmi.12871] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2014] [Indexed: 11/29/2022]
Abstract
The spindle assembly checkpoint (SAC) plays a critical role in preventing mitotic errors by inhibiting anaphase until all kinetochores are correctly attached to spindle microtubules. In spite of the economic and medical importance of filamentous fungi, relatively little is known about the behavior of SAC proteins in these organisms. In our efforts to understand the role of γ-tubulin in cell cycle regulation, we have created functional fluorescent protein fusions of four SAC proteins in Aspergillus nidulans, the homologs of Mad2, Mps1, Bub1/BubR1 and Bub3. Time-lapse imaging reveals that SAC proteins are in distinct compartments of the cell until early mitosis when they co-localize at the spindle pole body. SAC activity is, thus, spatially regulated in A. nidulans. Likewise, Cdc20, an activator of the anaphase-promoting complex/cyclosome, is excluded from interphase nuclei, but enters nuclei at mitotic onset and accumulates to a higher level in mitotic nuclei than in the surrounding nucleoplasm before leaving in anaphase/telophase. The activity of this critical cell cycle regulatory complex is likely regulated by the location of Cdc20. Finally, the γ-tubulin mutation mipAD159 causes a nuclear-specific failure of nuclear localization of Mps1 and Bub1/R1 but not of Cdc20, Bub3 or Mad2.
Collapse
Affiliation(s)
- Heather Edgerton
- Department of Molecular Biosciences, University of Kansas, 1200 Sunnyside Ave., Lawrence, KS, 66045, USA
| | | | | |
Collapse
|
48
|
Markossian S, Suresh S, Osmani AH, Osmani SA. Nup2 requires a highly divergent partner, NupA, to fulfill functions at nuclear pore complexes and the mitotic chromatin region. Mol Biol Cell 2014; 26:605-21. [PMID: 25540430 PMCID: PMC4325833 DOI: 10.1091/mbc.e14-09-1359] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Among nuclear pore proteins, Nup2 is unique because it transfers to the mitotic chromatin region to fulfill unknown functions. Analysis of Nup2 and a novel targeting partner, NupA, shows that they are required for normal anaphase and nucleokinesis. Their functions also involve an import pathway for Mad1 but apparently not general nuclear protein import. Chromatin and nuclear pore complexes (NPCs) undergo dramatic changes during mitosis, which in vertebrates and Aspergillus nidulans involves movement of Nup2 from NPCs to the chromatin region to fulfill unknown functions. This transition is shown to require the Cdk1 mitotic kinase and be promoted prematurely by ectopic expression of the NIMA kinase. Nup2 localizes with a copurifying partner termed NupA, a highly divergent yet essential NPC protein. NupA and Nup2 locate throughout the chromatin region during prophase but during anaphase move to surround segregating DNA. NupA function is shown to involve targeting Nup2 to its interphase and mitotic locations. Deletion of either Nup2 or NupA causes identical mitotic defects that initiate a spindle assembly checkpoint (SAC)–dependent mitotic delay and also cause defects in karyokinesis. These mitotic problems are not caused by overall defects in mitotic NPC disassembly–reassembly or general nuclear import. However, without Nup2 or NupA, although the SAC protein Mad1 locates to its mitotic locations, it fails to locate to NPCs normally in G1 after mitosis. Collectively the study provides new insight into the roles of Nup2 and NupA during mitosis and in a surveillance mechanism that regulates nucleokinesis when mitotic defects occur after SAC fulfillment.
Collapse
Affiliation(s)
- Sarine Markossian
- Laboratory of Gene Regulation and Development, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | | | - Aysha H Osmani
- Department of Molecular Genetics, Ohio State University, Columbus, OH 43210
| | - Stephen A Osmani
- Department of Molecular Genetics, Ohio State University, Columbus, OH 43210
| |
Collapse
|
49
|
Hooper SL, Burstein HJ. Minimization of extracellular space as a driving force in prokaryote association and the origin of eukaryotes. Biol Direct 2014; 9:24. [PMID: 25406691 PMCID: PMC4289276 DOI: 10.1186/1745-6150-9-24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 11/03/2014] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Internalization-based hypotheses of eukaryotic origin require close physical association of host and symbiont. Prior hypotheses of how these associations arose include chance, specific metabolic couplings between partners, and prey-predator/parasite interactions. Since these hypotheses were proposed, it has become apparent that mixed-species, close-association assemblages (biofilms) are widespread and predominant components of prokaryotic ecology. Which forces drove prokaryotes to evolve the ability to form these assemblages are uncertain. Bacteria and archaea have also been found to form membrane-lined interconnections (nanotubes) through which proteins and RNA pass. These observations, combined with the structure of the nuclear envelope and an energetic benefit of close association (see below), lead us to propose a novel hypothesis of the driving force underlying prokaryotic close association and the origin of eukaryotes. RESULTS Respiratory proton transport does not alter external pH when external volume is effectively infinite. Close physical association decreases external volume. For small external volumes, proton transport decreases external pH, resulting in each transported proton increasing proton motor force to a greater extent. We calculate here that in biofilms this effect could substantially decrease how many protons need to be transported to achieve a given proton motor force. Based as it is solely on geometry, this energetic benefit would occur for all prokaryotes using proton-based respiration. CONCLUSIONS This benefit may be a driving force in biofilm formation. Under this hypothesis a very wide range of prokaryotic species combinations could serve as eukaryotic progenitors. We use this observation and the discovery of prokaryotic nanotubes to propose that eukaryotes arose from physically distinct, functionally specialized (energy factory, protein factory, DNA repository/RNA factory), obligatorily symbiotic prokaryotes in which the protein factory and DNA repository/RNA factory cells were coupled by nanotubes and the protein factory ultimately internalized the other two. This hypothesis naturally explains many aspects of eukaryotic physiology, including the nuclear envelope being a folded single membrane repeatedly pierced by membrane-bound tubules (the nuclear pores), suggests that species analogous or homologous to eukaryotic progenitors are likely unculturable as monocultures, and makes a large number of testable predictions. REVIEWERS This article was reviewed by Purificación López-García and Toni Gabaldón.
Collapse
Affiliation(s)
- Scott L Hooper
- Department of Biological Sciences, Ohio University, Athens, OH 45701 USA
| | - Helaine J Burstein
- Department of Biological Sciences, Ohio University, Athens, OH 45701 USA
| |
Collapse
|
50
|
Dynamics of the establishment of multinucleate compartments in Fusarium oxysporum. EUKARYOTIC CELL 2014; 14:78-85. [PMID: 25398376 DOI: 10.1128/ec.00200-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nuclear dynamics can vary widely between fungal species and between stages of development of fungal colonies. Here we compared nuclear dynamics and mitotic patterns between germlings and mature hyphae in Fusarium oxysporum. Using fluorescently labeled nuclei and live-cell imaging, we show that F. oxysporum is subject to a developmental transition from a uninucleate to a multinucleate state after completion of colony initiation. We observed a special type of hypha that exhibits a higher growth rate, possibly acting as a nutrient scout. The higher growth rate is associated with a higher nuclear count and mitotic waves involving 2 to 6 nuclei in the apical compartment. Further, we found that dormant nuclei of intercalary compartments can reenter the mitotic cycle, resulting in multinucleate compartments with up to 18 nuclei in a single compartment.
Collapse
|