1
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Ay S, Di Nunzio F. HIV-Induced CPSF6 Condensates. J Mol Biol 2023; 435:168094. [PMID: 37061085 DOI: 10.1016/j.jmb.2023.168094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 04/06/2023] [Accepted: 04/08/2023] [Indexed: 04/17/2023]
Abstract
Viruses are obligate parasites that rely on their host's cellular machinery for replication. To facilitate their replication cycle, many viruses have been shown to remodel the cellular architecture by inducing the formation of membraneless organelles (MLOs). Eukaryotic cells have evolved MLOs that are highly dynamic, self-organizing microenvironments that segregate biological processes and increase the efficiency of reactions by concentrating enzymes and substrates. In the context of viral infections, MLOs can be utilized by viruses to complete their replication cycle. This review focuses on the pathway used by the HIV-1 virus to remodel the nuclear landscape of its host, creating viral/host niches that enable efficient viral replication. Specifically, we discuss how the interaction between the HIV-1 capsid and the cellular factor CPSF6 triggers the formation of nuclear MLOs that support nuclear reverse transcription and viral integration in favored regions of the host chromatin. This review compiles current knowledge on the origin of nuclear HIV-MLOs and their role in early post-nuclear entry steps of the HIV-1 replication cycle.
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Affiliation(s)
- Selen Ay
- Advanced Molecular Virology Unit, Department of Virology, Institut Pasteur, Université Paris Cité, 75015 Paris, France
| | - Francesca Di Nunzio
- Advanced Molecular Virology Unit, Department of Virology, Institut Pasteur, Université Paris Cité, 75015 Paris, France.
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2
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Evans DE, Graumann K. Editorial: Understanding the key border: Structure, function, and dynamics of the plant nuclear envelope. Front Plant Sci 2022; 13:998823. [PMID: 35991402 PMCID: PMC9382306 DOI: 10.3389/fpls.2022.998823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
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3
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Abstract
The eukaryotic nucleus shows organized structures of chromosomes, transcriptional components and their associated proteins. It has been believed that such a dense nuclear environment prevents the formation of a cytoskeleton-like network of protein filaments. However, accumulating evidence suggests that the cell nucleus also possesses structural filamentous components to support nuclear organization and compartments, which are referred to as nucleoskeleton proteins. Nucleoskeleton proteins including lamins and actin influence nuclear dynamics including transcriptional regulation, chromatin organization and DNA damage responses. Furthermore, these nucleoskeleton proteins play a pivotal role in cellular differentiation and animal development. In this commentary, we discuss how nucleoskeleton-based regulatory mechanisms orchestrate nuclear dynamics.
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Affiliation(s)
- Kei Miyamoto
- Graduate School of Biology-Oriented Science and Technology, Kindai University, 930 Nishimitani, Kinokawa-shi, Wakayama 649-6493, Japan
| | - Masahiko Harata
- Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Aramaki Aza-Aoba 468-1, Aoba-ku, Sendai 980-0845, Japan
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4
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Park JW, Han SB, Hah J, Lee G, Kim JK, Kim SH, Kim DH. Biological Aging Modulates Cell Migration via Lamin A/C-Dependent Nuclear Motion. Micromachines (Basel) 2020; 11:E801. [PMID: 32847135 PMCID: PMC7570206 DOI: 10.3390/mi11090801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 12/13/2022]
Abstract
Aging is a progressive functional decline in organs and tissues over time and typically represents the accumulation of psychological and social changes in a human being. Diverse diseases, such as cardiovascular, musculoskeletal, and neurodegenerative disorders, are now understood to be caused by aging. While biological assessment of aging mainly focuses on the gradual changes that occur either on the molecular scale, for example, alteration of gene expression and epigenetic modification, or on larger scales, for example, changes in muscle strength and cardiac function, the mechanics that regulates the behavior of individual cells and interactions between the internal elements of cells, are largely missing. In this study, we show that the dynamic features of migrating cells across different human ages could help to establish the underlying mechanism of biological age-dependent cellular functional decline. To determine the relationship between cellular dynamics and human age, we identify the characteristic relationship between cell migration and nuclear motion which is tightly regulated by nucleus-bound cytoskeletal organization. This analysis demonstrates that actomyosin contractility-dependent nuclear motion plays a key role in cell migration. We anticipate this study to provide noble biophysical insights on biological aging in order to precisely diagnose age-related chronic diseases.
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Affiliation(s)
- Jung-Won Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
| | - Seong-Beom Han
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
| | - Jungwon Hah
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
| | - Geonhui Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
| | - Jeong-Ki Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
| | - Soo Hyun Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
- Center for Biomaterials, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 02792, Korea
| | - Dong-Hwee Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea; (J.-W.P.); (S.-B.H.); (J.H.); (G.L.); (J.-K.K.); (S.H.K.)
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5
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Makhija E, Jagielska A, Zhu L, Bost AC, Ong W, Chew SY, Shivashankar GV, Van Vliet KJ. Mechanical Strain Alters Cellular and Nuclear Dynamics at Early Stages of Oligodendrocyte Differentiation. Front Cell Neurosci 2018; 12:59. [PMID: 29559894 PMCID: PMC5845683 DOI: 10.3389/fncel.2018.00059] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/19/2018] [Indexed: 11/13/2022] Open
Abstract
Mechanical and physical stimuli including material stiffness and topography or applied mechanical strain have been demonstrated to modulate differentiation of glial progenitor and neural stem cells. Recent studies probing such mechanotransduction in oligodendrocytes have focused chiefly on the biomolecular components. However, the cell-level biophysical changes associated with such responses remain largely unknown. Here, we explored mechanotransduction in oligodendrocyte progenitor cells (OPCs) during the first 48 h of differentiation induction by quantifying the biophysical state in terms of nuclear dynamics, cytoskeleton organization, and cell migration. We compared these mechanophenotypic changes in OPCs exposed to both chemical cues (differentiation factors) and mechanical cues (static tensile strain of 10%) with those exposed to only those chemical cues. We observed that mechanical strain significantly hastened the dampening of nuclear fluctuations and decreased OPC migration, consistent with the progression of differentiation. Those biophysical changes were accompanied by increased production of the intracellular microtubule network. These observations provide insights into mechanisms by which mechanical strain of physiological magnitude could promote differentiation of progenitor cells to oligodendrocytes via inducing intracellular biophysical responses over hours to days post induction.
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Affiliation(s)
- Ekta Makhija
- BioSystems and Micromechanics Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore
| | - Anna Jagielska
- BioSystems and Micromechanics Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Lena Zhu
- BioSystems and Micromechanics Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Alexander C Bost
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - William Ong
- NTU Institute for Health Technologies (Health Tech NTU), Interdisciplinary Graduate School, Nanyang Technological University, Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Sing Y Chew
- BioSystems and Micromechanics Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - G V Shivashankar
- BioSystems and Micromechanics Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore.,Mechanobiology Institute, Singapore, Singapore.,The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Krystyn J Van Vliet
- BioSystems and Micromechanics Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, CREATE, Singapore, Singapore.,Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
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6
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Chitale S, Richly H. Nuclear organization of nucleotide excision repair is mediated by RING1B dependent H2A-ubiquitylation. Oncotarget 2018; 8:30870-30887. [PMID: 28416769 PMCID: PMC5458174 DOI: 10.18632/oncotarget.16142] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 02/15/2017] [Indexed: 01/10/2023] Open
Abstract
One of the major cellular DNA repair pathways is nucleotide excision repair (NER). It is the primary pathway for repair of various DNA lesions caused by exposure to ultraviolet (UV) light, such as cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts. Although lesion-containing DNA associates with the nuclear matrix after UV irradiation it is still not understood how nuclear organization affects NER. Analyzing unscheduled DNA synthesis (UDS) indicates that NER preferentially occurs in specific nuclear areas, viz the nucleolus. Upon inducing localized damage, we observe migration of damaged DNA towards the nucleolus. Employing a LacR-based tethering system we demonstrate that H2A-ubiquitylation via the UV-RING1B complex localizes chromatin close to the nucleolus. We further show that the H2A-ubiquitin binding protein ZRF1 resides in the nucleolus, and that it anchors ubiquitylated chromatin along with XPC. Our data thus provide insight into the sub-nuclear organization of NER and reveal a novel role for histone H2A-ubiquitylation.
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Affiliation(s)
- Shalaka Chitale
- Laboratory of Molecular Epigenetics, Institute of Molecular Biology, Mainz, Germany, Ackermannweg, Mainz, Germany.,Faculty of Biology, Johannes Gutenberg University, Mainz, Germany
| | - Holger Richly
- Laboratory of Molecular Epigenetics, Institute of Molecular Biology, Mainz, Germany, Ackermannweg, Mainz, Germany
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7
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Gomez-Lamarca MJ, Falo-Sanjuan J, Stojnic R, Abdul Rehman S, Muresan L, Jones ML, Pillidge Z, Cerda-Moya G, Yuan Z, Baloul S, Valenti P, Bystricky K, Payre F, O'Holleran K, Kovall R, Bray SJ. Activation of the Notch Signaling Pathway In Vivo Elicits Changes in CSL Nuclear Dynamics. Dev Cell 2018; 44:611-623.e7. [PMID: 29478922 PMCID: PMC5855320 DOI: 10.1016/j.devcel.2018.01.020] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 11/27/2017] [Accepted: 01/23/2018] [Indexed: 12/27/2022]
Abstract
A key feature of Notch signaling is that it directs immediate changes in transcription via the DNA-binding factor CSL, switching it from repression to activation. How Notch generates both a sensitive and accurate response-in the absence of any amplification step-remains to be elucidated. To address this question, we developed real-time analysis of CSL dynamics including single-molecule tracking in vivo. In Notch-OFF nuclei, a small proportion of CSL molecules transiently binds DNA, while in Notch-ON conditions CSL recruitment increases dramatically at target loci, where complexes have longer dwell times conferred by the Notch co-activator Mastermind. Surprisingly, recruitment of CSL-related corepressors also increases in Notch-ON conditions, revealing that Notch induces cooperative or "assisted" loading by promoting local increase in chromatin accessibility. Thus, in vivo Notch activity triggers changes in CSL dwell times and chromatin accessibility, which we propose confer sensitivity to small input changes and facilitate timely shut-down.
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Affiliation(s)
- Maria J Gomez-Lamarca
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Julia Falo-Sanjuan
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Robert Stojnic
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Sohaib Abdul Rehman
- Cambridge Advanced Imaging Centre, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Leila Muresan
- Cambridge Advanced Imaging Centre, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Matthew L Jones
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Zoe Pillidge
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Gustavo Cerda-Moya
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Zhenyu Yuan
- University of Cincinnati College of Medicine, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267-0524, USA
| | - Sarah Baloul
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Phillippe Valenti
- Centre de Biologie du Développement/UMR5547, CBI (Centre de Biologie Intégrative) University of Toulouse/CNRS, 118 Rte de Narbonne, 31062 Toulouse, France
| | - Kerstin Bystricky
- LBME/UMR5099, CBI (Centre de Biologie Intégrative) University of Toulouse/CNRS, 118 Rte de Narbonne, 31062 Toulouse, France
| | - Francois Payre
- Centre de Biologie du Développement/UMR5547, CBI (Centre de Biologie Intégrative) University of Toulouse/CNRS, 118 Rte de Narbonne, 31062 Toulouse, France
| | - Kevin O'Holleran
- Cambridge Advanced Imaging Centre, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Rhett Kovall
- University of Cincinnati College of Medicine, Department of Molecular Genetics, Biochemistry and Microbiology, 231 Albert Sabin Way, Cincinnati, OH 45267-0524, USA
| | - Sarah J Bray
- Department of Physiology Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK.
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8
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Abstract
"Where do we go from here?" is the underlying question regarding the future (perhaps foreseeable) developments in computational chemistry. Although this young discipline has already permeated practically all of chemistry, it is likely to become even more powerful with the rapid development of computational hard- and software.
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Affiliation(s)
- Stefan Grimme
- Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115, Bonn, Germany
| | - Peter R Schreiner
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring 17, 35392, Giessen, Germany
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9
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Corral-Ramos C, Roca MG, Di Pietro A, Roncero MIG, Ruiz-Roldán C. Autophagy contributes to regulation of nuclear dynamics during vegetative growth and hyphal fusion in Fusarium oxysporum. Autophagy 2015; 11:131-44. [PMID: 25560310 DOI: 10.4161/15548627.2014.994413] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In the fungal pathogen Fusarium oxysporum, vegetative hyphal fusion triggers nuclear mitotic division in the invading hypha followed by migration of a nucleus into the receptor hypha and degradation of the resident nucleus. Here we examined the role of autophagy in fusion-induced nuclear degradation. A search of the F. oxysporum genome database for autophagy pathway components identified putative orthologs of 16 core autophagy-related (ATG) genes in yeast, including the ubiquitin-like protein Atg8, which is required for the formation of autophagosomal membranes. F. oxysporum Foatg8Δ mutants were generated in a strain harboring H1-cherry fluorescent protein (ChFP)-labeled nuclei to facilitate analysis of nuclear dynamics. The Foatg8Δ mutants did not show MDC-positive staining in contrast to the wild type and the FoATG8-complemented (cFoATG8) strain, suggesting that FoAtg8 is required for autophagy in F. oxysporum. The Foatg8Δ strains displayed reduced rates of hyphal growth, conidiation, and fusion, and were significantly attenuated in virulence on tomato plants and in the nonvertebrate animal host Galleria mellonella. In contrast to wild-type hyphae, which are almost exclusively composed of uninucleated hyphal compartments, the hyphae of the Foatg8Δ mutants contained a significant fraction of hyphal compartments with 2 or more nuclei. The increase in the number of nuclei per hyphal compartment was particularly evident after hyphal fusion events. Time-lapse microscopy analyses revealed abnormal mitotic patterns during vegetative growth in the Foatg8Δ mutants. Our results suggest that autophagy mediates nuclear degradation after hyphal fusion and has a general function in the control of nuclear distribution in F. oxysporum.
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Key Words
- Atg, autophagy-related
- BLAST, basic local alignment search tool
- CFW, calcofluor white
- ChFP, cherry fluorescent protein
- DIC, differential interference contrast
- Fusarium oxysporum
- GFP, green fluorescent protein
- HygR, hygromycin resistant
- MDC, monodansylcadaverine
- ORF, open reading frame
- PCR, polymerase chain reaction
- PDA, potato dextrose agar
- PDB, potato dextrose broth
- PMSF, phenylmethylsulfonyl fluoride
- SM, synthetic medium
- WT, wild-type
- autophagy
- filamentous fungi
- gDNA, genomic DNA
- hyphal fusion
- nuclear dynamics
- virulence
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Affiliation(s)
- Cristina Corral-Ramos
- a Departamento de Genética; Universidad de Córdoba; Campus de Excelencia Agroalimentario ; Córdoba , Spain
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10
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Shav-Tal Y, Lammerding J. Design (and) principles of nuclear dynamics in Stockholm. Nucleus 2015; 6:425-9. [PMID: 26730816 PMCID: PMC4915483 DOI: 10.1080/19491034.2015.1128609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 11/26/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022] Open
Abstract
The structural organization of the nucleus and its content has drawn increasing interest in recent years, as it is has become evident that the spatial and temporal arrangement of the genome and associated structures plays a crucial role in transcriptional regulation and numerous other functions. Shining light on the dynamic nature of this organization, along with the processes controlling it, were the topics of the Wenner-Gren Foundations international symposium "Nuclear Dynamics: Design (and) Principles." The meeting, organized by Piorgiogio Percipalle, Maria Vartiainen, Neus Visa, and Ann-Kristin Östlund-Farrants, brought over 60 participants, including 20 international speakers, to Stockholm, Sweden from August 19-22, 2015 to share the latest developments in the field. Given the unpublished nature of many of the talks, we have focused on covering the discussed topics and highlighting the latest trends in this exciting and rapidly evolving field.
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Affiliation(s)
- Yaron Shav-Tal
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology; Bar-Ilan University; Ramat Gan, Israel
| | - Jan Lammerding
- Weill Institute for Cell and Molecular Biology; Meinig School of Biomedical Engineering; Cornell University; Ithaca, NY USA
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11
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Bellec L, Maurer-Alcala XX, Katz LA. Characterization of the life cycle and heteromeric nature of the macronucleus of the ciliate Chilodonella uncinata using fluorescence microscopy. J Eukaryot Microbiol 2014; 61:313-6. [PMID: 24547950 DOI: 10.1111/jeu.12109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 01/10/2014] [Accepted: 01/10/2014] [Indexed: 11/30/2022]
Abstract
Only a limited number of studies exist on the life cycles of nonmodel ciliates such as Chilodonella uncinata (Cl: Phyllopharyngea). The handful of papers on this taxon indicate the presence of a heteromeric macronucleus, marked by separate DNA-rich and DNA-poor regions. Here, we study the life cycle of C. uncinata using confocal laser scanning microscopy with 4',6-diamidino-2-phenylindole staining, which allows us to differentiate nuclear dynamics of the micronucleus and the macronucleus during life-cycle stages. We photo-documented various stages and confirmed aspects of the development of the new macronucleus previously characterized by electron microscopy. We further reveal the heteromeric structure of the macronucleus with Z-stacks and three-dimensional (3D) reconstructions. We find no evidence for the presence of an endosome at the center of the macronucleus during vegetative growth. In addition to illustrating the life cycle of this ciliate, the approaches developed for this study will enable additional comparative analyses of nuclear dynamics using fluorescence microscopy.
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Affiliation(s)
- Laure Bellec
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063
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12
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Li W, Rego LGC, Bai FQ, Wang J, Jia R, Xie LM, Zhang HX. What Makes Hydroxamate a Promising Anchoring Group in Dye-Sensitized Solar Cells? Insights from Theoretical Investigation. J Phys Chem Lett 2014; 5:3992-3999. [PMID: 26276483 DOI: 10.1021/jz501973d] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report, from a theoretical point of view, the first comparative study between the highly water-stable hydroxamate and the widely used carboxylate, in addition to the robust phosphate anchors. Theoretical calculations reveal that hydroxamate would be better for photoabsorption. A quantum dynamics description of the interfacial electron transfer (IET), including the underlying nuclear motion effect, is presented. We find that both hydroxamate and carboxylate would have efficient IET character; for phosphate the injection time is significantly longer (several hundred femtoseconds). We also verified that the symmetry of the geometry of the anchoring group plays important roles in the electronic charge delocalization. We conclude that hydroxamate can be a promising anchoring group, as compared to carboxylate and phosphate, due to its better photoabsorption and comparable IET time scale as well as the experimental advantage of water stability. We expect the implications of these findings to be relevant for the design of more efficient anchoring groups for dye-sensitized solar cell (DSSC) application.
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Affiliation(s)
- Wei Li
- †Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Luis G C Rego
- ‡Department of Physics, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina 88040-900, Brazil
| | - Fu-Quan Bai
- †Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Jian Wang
- †Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Ran Jia
- †Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Li-Ming Xie
- †Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China
| | - Hong-Xing Zhang
- †Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China
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13
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Kinor N, Shav-Tal Y. The dynamics of the alternatively spliced NOL7 gene products and role in nucleolar architecture. Nucleus 2012; 2:229-45. [PMID: 21818416 DOI: 10.4161/nucl.2.3.15893] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 04/05/2011] [Accepted: 04/21/2011] [Indexed: 11/19/2022] Open
Abstract
Three alternatively spliced forms of the human NOL7 gene coding for relatively small proteins were identified. The two shorter forms were generated by intron retention events, and each isoform was differently localized within the cell. The NOL7-SP1 long form (29 kD) localized to the nucleolus, SP2 was nucleoplasmic, while SP3 was distributed throughout the whole cell. NOL7-SP1 was confined to the nucleolar granular component, and during cell division disassociated from the nucleolus. Knockdown of NOL7-SP1 levels abrogated nucleolar architecture, in particular the internal regions, and reduced cell proliferation. Analysis of the nucleolar dynamics of the SP1 protein during interphase showed nucleolar high binding affinity. Dissection of protein domains showed that nucleolar targeting was mediated by a unique C-terminal nucleolar localization sequence (NoLS). However, this sequence was not sufficient for conferring high binding affinity, which required additional regions of the protein. Our analysis shows that NOL7 is important for maintaining internal nucleolar structure and cell growth rates, and that while specific protein localization can be obtained by specific short localization motifs, nucleolar residency through binding must be mediated by a synergistic combination of protein modules.
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Affiliation(s)
- Noa Kinor
- The Mina & Everard Goodman Institute of Nanotechnology, Bar-Ilan University; Ramat Gan, Israel
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14
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Abstract
Molecular imaging in living cells or organisms now allows us to observe macromolecular assemblies with a time resolution sufficient to address cause-and-effect relationships on specific molecules. These emerging technologies have gained much interest from the scientific community since they have been able to reveal novel concepts in cell biology, thereby changing our vision of the cell. One main paradigm is that cells stochastically vary, thus implying that population analysis may be misleading. In fact, cells should be analyzed within time-resolved single-cell experiments rather than being compared to other cells within a population. Technological imaging developments as well as the stochastic events present in gene expression have been reviewed. Here, we discuss how the structural organization of the nucleus is revealed using noninvasive single-cell approaches, which ultimately lead to the resolution required for the analysis of highly controlled molecular processes taking place within live cells. We also describe the efforts being made towards physiological approaches within the context of living organisms.
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Affiliation(s)
- Yaron Shav-Tal
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
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15
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Abstract
To understand how nuclear machineries are targeted to accurate locations during nuclear assembly, we investigated the pathway of the ribosomal RNA (rRNA) processing machinery towards ribosomal genes (nucleolar organizer regions [NORs]) at exit of mitosis. To follow in living cells two permanently transfected green fluorescence protein-tagged nucleolar proteins, fibrillarin and Nop52, from metaphase to G1, 4-D time-lapse microscopy was used. In early telophase, fibrillarin is concentrated simultaneously in prenucleolar bodies (PNBs) and NORs, whereas PNB-containing Nop52 forms later. These distinct PNBs assemble at the chromosome surface. Analysis of PNB movement does not reveal the migration of PNBs towards the nucleolus, but rather a directional flow between PNBs and between PNBs and the nucleolus, ensuring progressive delivery of proteins into nucleoli. This delivery appeared organized in morphologically distinct structures visible by electron microscopy, suggesting transfer of large complexes. We propose that the temporal order of PNB assembly and disassembly controls nucleolar delivery of these proteins, and that accumulation of processing complexes in the nucleolus is driven by pre-rRNA concentration. Initial nucleolar formation around competent NORs appears to be followed by regroupment of the NORs into a single nucleolus 1 h later to complete the nucleolar assembly. This demonstrates the formation of one functional domain by cooperative interactions between different chromosome territories.
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Affiliation(s)
| | | | - Jan De Mey
- Institut Curie/Section de Recherche, UMR 146, 91405 Orsay, France
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