101
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Garcia-Jove Navarro M, Kashida S, Chouaib R, Souquere S, Pierron G, Weil D, Gueroui Z. RNA is a critical element for the sizing and the composition of phase-separated RNA-protein condensates. Nat Commun 2019; 10:3230. [PMID: 31324804 PMCID: PMC6642089 DOI: 10.1038/s41467-019-11241-6] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 06/27/2019] [Indexed: 01/01/2023] Open
Abstract
Liquid-liquid phase separation is thought to be a key organizing principle in eukaryotic cells to generate highly concentrated dynamic assemblies, such as the RNP granules. Numerous in vitro approaches have validated this model, yet a missing aspect is to take into consideration the complex molecular mixture and promiscuous interactions found in vivo. Here we report the versatile scaffold ArtiG to generate concentration-dependent RNA-protein condensates within living cells, as a bottom-up approach to study the impact of co-segregated endogenous components on phase separation. We demonstrate that intracellular RNA seeds the nucleation of the condensates, as it provides molecular cues to locally coordinate the formation of endogenous high-order RNP assemblies. Interestingly, the co-segregation of intracellular components ultimately impacts the size of the phase-separated condensates. Thus, RNA arises as an architectural element that can influence the composition and the morphological outcome of the condensate phases in an intracellular context.
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Affiliation(s)
- Marina Garcia-Jove Navarro
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Shunnichi Kashida
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France
| | - Racha Chouaib
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire de Biologie du Développement, F-75005, Paris, France.,School of Arts and Sciences, Lebanese International University (LIU), Beirut, Lebanon.,Faculty of Sciences, Lebanese University, Beirut, Lebanon
| | - Sylvie Souquere
- CNRS UMR-9196, Institut Gustave Roussy, F-94800, Villejuif, France
| | - Gérard Pierron
- CNRS UMR-9196, Institut Gustave Roussy, F-94800, Villejuif, France
| | - Dominique Weil
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire de Biologie du Développement, F-75005, Paris, France
| | - Zoher Gueroui
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005, Paris, France.
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102
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Bergstrand S, O'Brien EM, Farnebo M. The Cajal Body Protein WRAP53β Prepares the Scene for Repair of DNA Double-Strand Breaks by Regulating Local Ubiquitination. Front Mol Biosci 2019; 6:51. [PMID: 31334247 PMCID: PMC6624377 DOI: 10.3389/fmolb.2019.00051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 06/20/2019] [Indexed: 12/27/2022] Open
Abstract
Proper repair of DNA double-strand breaks is critical for maintaining genome integrity and avoiding disease. Modification of damaged chromatin has profound consequences for the initial signaling and regulation of repair. One such modification involves ubiquitination by E3 ligases RNF8 and RNF168 within minutes after DNA double-strand break formation, altering chromatin structure and recruiting factors such as 53BP1 and BRCA1 for repair via non-homologous end-joining (NHEJ) and homologous recombination (HR), respectively. The WD40 protein WRAP53β plays an essential role in localizing RNF8 to DNA breaks by scaffolding its interaction with the upstream factor MDC1. Loss of WRAP53β impairs ubiquitination at DNA lesions and reduces downstream repair by both NHEJ and HR. Intriguingly, WRAP53β depletion attenuates repair of DNA double-strand breaks more than depletion of RNF8, indicating functions other than RNF8-mediated ubiquitination. WRAP53β plays key roles with respect to the nuclear organelles Cajal bodies, including organizing the genome to promote associated transcription and collecting factors involved in maturation of the spliceosome and telomere elongation within these organelles. It is possible that similar functions may aid also in DNA repair. Here we describe the involvement of WRAP53β in Cajal bodies and DNA double-strand break repair in detail and explore whether and how these processes may be linked. We also discuss the possibility that the overexpression of WRAP53β detected in several cancer types may reflect its normal participation in the DNA damage response rather than oncogenic properties.
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Affiliation(s)
- Sofie Bergstrand
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Eleanor M O'Brien
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Marianne Farnebo
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.,Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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103
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Modic M, Grosch M, Rot G, Schirge S, Lepko T, Yamazaki T, Lee FCY, Rusha E, Shaposhnikov D, Palo M, Merl-Pham J, Cacchiarelli D, Rogelj B, Hauck SM, von Mering C, Meissner A, Lickert H, Hirose T, Ule J, Drukker M. Cross-Regulation between TDP-43 and Paraspeckles Promotes Pluripotency-Differentiation Transition. Mol Cell 2019; 74:951-965.e13. [PMID: 31047794 PMCID: PMC6561722 DOI: 10.1016/j.molcel.2019.03.041] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 02/12/2019] [Accepted: 03/28/2019] [Indexed: 01/22/2023]
Abstract
RNA-binding proteins (RBPs) and long non-coding RNAs (lncRNAs) are key regulators of gene expression, but their joint functions in coordinating cell fate decisions are poorly understood. Here we show that the expression and activity of the RBP TDP-43 and the long isoform of the lncRNA Neat1, the scaffold of the nuclear compartment "paraspeckles," are reciprocal in pluripotent and differentiated cells because of their cross-regulation. In pluripotent cells, TDP-43 represses the formation of paraspeckles by enhancing the polyadenylated short isoform of Neat1. TDP-43 also promotes pluripotency by regulating alternative polyadenylation of transcripts encoding pluripotency factors, including Sox2, which partially protects its 3' UTR from miR-21-mediated degradation. Conversely, paraspeckles sequester TDP-43 and other RBPs from mRNAs and promote exit from pluripotency and embryonic patterning in the mouse. We demonstrate that cross-regulation between TDP-43 and Neat1 is essential for their efficient regulation of a broad network of genes and, therefore, of pluripotency and differentiation.
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Affiliation(s)
- Miha Modic
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; The Francis Crick Institute, London NW1 1AT, UK; Department for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Markus Grosch
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Gregor Rot
- Institute of Molecular Life Sciences of the University of Zurich and Swiss Institute of Bioinformatics, 8057 Zurich, Switzerland
| | - Silvia Schirge
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tjasa Lepko
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tomohiro Yamazaki
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
| | - Flora C Y Lee
- The Francis Crick Institute, London NW1 1AT, UK; Department for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Ejona Rusha
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Dmitry Shaposhnikov
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Michael Palo
- The Francis Crick Institute, London NW1 1AT, UK; Department for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
| | - Juliane Merl-Pham
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 80939 Munich, Germany
| | - Davide Cacchiarelli
- Broad Institute of Harvard University/MIT, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Telethon Institute of Genetics and Medicine (TIGEM), NA 80078 Pozzuoli, Italy
| | - Boris Rogelj
- Department of Biotechnology, Jožef Stefan Institute, 1000 Ljubljana, Slovenia; Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia; Biomedical Research Institute BRIS, 1000 Ljubljana, Slovenia
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 80939 Munich, Germany
| | - Christian von Mering
- Institute of Molecular Life Sciences of the University of Zurich and Swiss Institute of Bioinformatics, 8057 Zurich, Switzerland
| | - Alexander Meissner
- Broad Institute of Harvard University/MIT, Cambridge, MA 02142, USA; Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA; Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Heiko Lickert
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
| | - Jernej Ule
- The Francis Crick Institute, London NW1 1AT, UK; Department for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.
| | - Micha Drukker
- Institute of Stem Cell Research, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Comprehensive Pneumology Center (CPC-M), Ludwig-Maximilians-Universität München, Asklepios Fachkliniken München-Gauting und Helmholtz Zentrum München, Max-Lebsche-Platz 31, 81377 Munich, Germany.
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104
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Hirose T, Yamazaki T, Nakagawa S. Molecular anatomy of the architectural NEAT1 noncoding RNA: The domains, interactors, and biogenesis pathway required to build phase-separated nuclear paraspeckles. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1545. [PMID: 31044562 DOI: 10.1002/wrna.1545] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 12/19/2022]
Abstract
Long noncoding RNAs (lncRNAs) are extremely diverse and have various significant physiological functions. lncRNAs generally associate with specific sets of RNA-binding proteins (RBPs) to form functional ribonucleoprotein (RNP) complexes. NEAT1 is a highly abundant lncRNA in the mammalian cell nucleus that associates with specific RBPs to form NEAT1 RNPs. Intriguingly, cellular NEAT1 RNPs are extraordinarily large and can be detected using an optical microscope. These gigantic RNPs, so-called paraspeckles, are a type of membraneless nuclear body. Paraspeckles contain approximately 50 NEAT1 RNA molecules together with characteristic RBPs possessing aggregation-prone prion-like domains. Paraspeckle formation proceeds on the nascent NEAT1 transcript in conjunction with NEAT1 biogenesis, which exhibits various features that differ from those exhibited by mRNA biogenesis, including a lack of introns, noncanonical 3' end formation, and nuclear retention. These unique features may be required for the mechanism of paraspeckle formation. NEAT1 possesses three distinct RNA domains (A, B, and C), which function in stabilization (A), isoform switching (B), and paraspeckle assembly (C). In particular, the central C domain contains smaller subdomains that are high-affinity binding sites for the essential paraspeckle proteins (NONO and SFPQ) that subsequently polymerize along NEAT1. Subsequent recruitment of additional essential PSPs (FUS and RBM14) induces liquid-liquid phase separation to build a massive paraspeckle structure. Thus, the molecular anatomy of the NEAT1 arcRNA provides an ideal model to understand how lncRNAs form the functional RNP machinery. This article is characterized under: RNA Export and Localization > Nuclear Export/Import RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Tetsuro Hirose
- Laboratory of RNA Biofucntion, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Tomohiro Yamazaki
- Laboratory of RNA Biofucntion, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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105
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Directing curli polymerization with DNA origami nucleators. Nat Commun 2019; 10:1395. [PMID: 30918257 PMCID: PMC6437208 DOI: 10.1038/s41467-019-09369-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 03/07/2019] [Indexed: 01/16/2023] Open
Abstract
The physiological or pathological formation of fibrils often relies on molecular-scale nucleators that finely control the kinetics and structural features. However, mechanistic understanding of how protein nucleators mediate fibril formation in cells remains elusive. Here, we develop a CsgB-decorated DNA origami (CB-origami) to mimic protein nucleators in Escherichia coli biofilm that direct curli polymerization. We show that CB-origami directs curli subunit CsgA monomers to form oligomers and then accelerates fibril formation by increasing the proliferation rate of primary pathways. Fibrils grow either out from (departure mode) or towards the nucleators (arrival mode), implying two distinct roles of CsgB: as nucleation sites and as trap sites to capture growing nanofibrils in vicinity. Curli polymerization follows typical stop-and-go dynamics but exhibits a higher instantaneous elongation rate compared with independent fibril growth. This origami nucleator thus provides an in vitro platform for mechanistically probing molecular nucleation and controlling directional fibril polymerization for bionanotechnology.
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106
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Falahati H, Haji-Akbari A. Thermodynamically driven assemblies and liquid-liquid phase separations in biology. SOFT MATTER 2019; 15:1135-1154. [PMID: 30672955 DOI: 10.1039/c8sm02285b] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The sustenance of life depends on the high degree of organization that prevails through different levels of living organisms, from subcellular structures such as biomolecular complexes and organelles to tissues and organs. The physical origin of such organization is not fully understood, and even though it is clear that cells and organisms cannot maintain their integrity without consuming energy, there is growing evidence that individual assembly processes can be thermodynamically driven and occur spontaneously due to changes in thermodynamic variables such as intermolecular interactions and concentration. Understanding the phase separation in vivo requires a multidisciplinary approach, integrating the theory and physics of phase separation with experimental and computational techniques. This paper aims at providing a brief overview of the physics of phase separation and its biological implications, with a particular focus on the assembly of membraneless organelles. We discuss the underlying physical principles of phase separation from its thermodynamics to its kinetics. We also overview the wide range of methods utilized for experimental verification and characterization of phase separation of membraneless organelles, as well as the utility of molecular simulations rooted in thermodynamics and statistical physics in understanding the governing principles of thermodynamically driven biological self-assembly processes.
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Affiliation(s)
- Hanieh Falahati
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA.
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107
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Molecular Mechanisms of Neurodegeneration Related to C9orf72 Hexanucleotide Repeat Expansion. Behav Neurol 2019; 2019:2909168. [PMID: 30774737 PMCID: PMC6350563 DOI: 10.1155/2019/2909168] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/28/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022] Open
Abstract
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 (C9orf72) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2–10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
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108
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Sawyer IA, Sturgill D, Dundr M. Membraneless nuclear organelles and the search for phases within phases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1514. [DOI: 10.1002/wrna.1514] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/20/2018] [Accepted: 09/27/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Iain A. Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School Rosalind Franklin University of Medicine and Science North Chicago Illinois
- Laboratory of Receptor Biology and Gene Expression National Cancer Institute, National Institutes of Health Bethesda Maryland
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression National Cancer Institute, National Institutes of Health Bethesda Maryland
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School Rosalind Franklin University of Medicine and Science North Chicago Illinois
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109
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Yong W, Yu D, Jun Z, Yachen D, Weiwei W, Midie X, Xingzhu J, Xiaohua W. Long noncoding RNA NEAT1, regulated by LIN28B, promotes cell proliferation and migration through sponging miR-506 in high-grade serous ovarian cancer. Cell Death Dis 2018; 9:861. [PMID: 30154460 PMCID: PMC6113267 DOI: 10.1038/s41419-018-0908-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/06/2018] [Accepted: 07/22/2018] [Indexed: 02/07/2023]
Abstract
The aberrant expression of long noncoding RNAs (lncRNAs) has been reported frequently in specific cancers, including high-grade serous ovarian cancer (HGSOC). The purpose of the present study was to explore the clinical significance and underlying mechanisms of a significantly dysregulated lncRNA (NEAT1) in HGSOC. Our results showed that elevated NEAT1 expression in human HGSOC specimens correlated with a poor prognosis. Functional experiments demonstrated that knockdown of NEAT1 significantly prohibited ovarian cancer cell proliferation and invasion in vitro and restrained tumor growth in vivo. LIN28B was identified by bioinformatics analysis along with experimental evidence as a direct actor that enhanced NEAT1 stability. A rescue functional assay confirmed that the LIN28B/NEAT1 axis contributed to oncogenic functions in ovarian cancer cells. Moreover, gene expression profile data and dual luciferase reporter assay results demonstrated that NEAT1 functioned as a competing endogenous RNA (ceRNA) for miR-506 to promote cell proliferation and migration. Taken together, our results showed that NEAT1, stabilized by LIN28B, promoted HGSOC progression by sponging miR-506. Thus, NEAT1 can be regarded as a vital diagnostic biomarker for HGSOC and a therapeutic target.
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Affiliation(s)
- Wu Yong
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Deng Yu
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Zhu Jun
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Duan Yachen
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Weng Weiwei
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Xu Midie
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Ju Xingzhu
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Wu Xiaohua
- Department of Gynecologic Oncology, Fudan University Shanghai Cancer Center, Shanghai, China.
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
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110
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Abstract
Eukaryotic cells organize their intracellular components into organelles that can be membrane-bound or membraneless. A large number of membraneless organelles, including nucleoli, Cajal bodies, P-bodies, and stress granules, exist as liquid droplets within the cell and arise from the condensation of cellular material in a process termed liquid-liquid phase separation (LLPS). Beyond a mere organizational tool, concentrating cellular components into membraneless organelles tunes biochemical reactions and improves cellular fitness during stress. In this review, we provide an overview of the molecular underpinnings of the formation and regulation of these membraneless organelles. This molecular understanding explains emergent properties of these membraneless organelles and shines new light on neurodegenerative diseases, which may originate from disturbances in LLPS and membraneless organelles.
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Affiliation(s)
- Edward Gomes
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - James Shorter
- From the Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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111
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Sawyer IA, Bartek J, Dundr M. Phase separated microenvironments inside the cell nucleus are linked to disease and regulate epigenetic state, transcription and RNA processing. Semin Cell Dev Biol 2018; 90:94-103. [PMID: 30017905 DOI: 10.1016/j.semcdb.2018.07.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 07/03/2018] [Indexed: 01/01/2023]
Abstract
Proteins and RNAs inside the cell nucleus are organized into distinct phases, also known as liquid-liquid phase separated (LLPS) droplet organelles or nuclear bodies. These regions exist within the spaces between chromatin-rich regions but their function is tightly linked to gene activity. They include major microscopically-observable structures such as the nucleolus, paraspeckle and Cajal body. The biochemical and assembly factors enriched inside these microenvironments regulate chromatin structure, transcription, and RNA processing, and other important cellular functions. Here, we describe published evidence that suggests nuclear bodies are bona fide LLPS droplet organelles and major regulators of the processes listed above. We also outline an updated "Supply or Sequester" model to describe nuclear body function, in which proteins or RNAs are supplied to surrounding genomic regions or sequestered away from their sites of activity. Finally, we describe recent evidence that suggests these microenvironments are both reflective and drivers of diverse pathophysiological states.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, United States; Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Jiri Bartek
- Danish Cancer, Society Research Center, Genome Integrity Unit, Copenhagen, Denmark; Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, United States.
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112
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Sobol M, Krausová A, Yildirim S, Kalasová I, Fáberová V, Vrkoslav V, Philimonenko V, Marášek P, Pastorek L, Čapek M, Lubovská Z, Uličná L, Tsuji T, Lísa M, Cvačka J, Fujimoto T, Hozak P. Nuclear phosphatidylinositol 4,5-bisphosphate islets contribute to efficient RNA polymerase II-dependent transcription. J Cell Sci 2018; 131:jcs.211094. [PMID: 29507116 DOI: 10.1242/jcs.211094] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/22/2018] [Indexed: 12/18/2022] Open
Abstract
This paper describes a novel type of nuclear structure - nuclear lipid islets (NLIs). They are of 40-100 nm with a lipidic interior, and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] molecules comprise a significant part of their surface. Most of NLIs have RNA at the periphery. Consistent with that, RNA is required for their integrity. The NLI periphery is associated with Pol II transcription machinery, including the largest Pol II subunit, transcription factors and NM1 (also known as NMI). The PtdIns(4,5)P2-NM1 interaction is important for Pol II transcription, since NM1 knockdown reduces the Pol II transcription level, and the overexpression of wild-type NM1 [but not NM1 mutated in the PtdIns(4,5)P2-binding site] rescues the transcription. Importantly, Pol II transcription is dependent on NLI integrity, because an enzymatic reduction of the PtdIns(4,5)P2 level results in a decrease of the Pol II transcription level. Furthermore, about half of nascent transcripts localise to NLIs, and transcriptionally active transgene loci preferentially colocalise with NLIs. We hypothesize that NLIs serve as a structural platform that facilitates the formation of Pol II transcription factories, thus participating in the formation of nuclear architecture competent for transcription.
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Affiliation(s)
- Margarita Sobol
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Alžběta Krausová
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Sukriye Yildirim
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Ilona Kalasová
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Veronika Fáberová
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Vladimír Vrkoslav
- Institute of Organic Chemistry and Biochemistry, CAS, v.v.i., Research Service Group of Mass Spectrometry, Flemingovo náměstí 2, 166 10, Prague 6, Czech Republic
| | - Vlada Philimonenko
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic.,Institute of Molecular Genetics, CAS, v.v.i., Electron Microscopy Core Facility, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Pavel Marášek
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Lukáš Pastorek
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic.,Institute of Molecular Genetics, CAS, v.v.i., Electron Microscopy Core Facility, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Martin Čapek
- Institute of Molecular Genetics, CAS, v.v.i., Light Microscopy Core Facility, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Zuzana Lubovská
- Institute of Molecular Genetics, CAS, v.v.i., Electron Microscopy Core Facility, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Lívia Uličná
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Takuma Tsuji
- Nagoya University Graduate School of Medicine, Department of Molecular Cell Biology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Miroslav Lísa
- University of Pardubice, Faculty of Chemical Technology, Department of Analytical Chemistry, Studentská 573, 532 10, Pardubice, Czech Republic
| | - Josef Cvačka
- Institute of Organic Chemistry and Biochemistry, CAS, v.v.i., Research Service Group of Mass Spectrometry, Flemingovo náměstí 2, 166 10, Prague 6, Czech Republic
| | - Toyoshi Fujimoto
- Nagoya University Graduate School of Medicine, Department of Molecular Cell Biology, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Pavel Hozak
- Institute of Molecular Genetics, CAS, v.v.i., Department of Biology of the Cell Nucleus, Vídeňská 1083, 142 20, Prague 4, Czech Republic .,Institute of Molecular Genetics, CAS, v.v.i., Division BIOCEV, Laboratory of Epigenetics of the Cell Nucleus, Průmyslová 595, 252 50, Vestec, Czech Republic.,Institute of Molecular Genetics, CAS, v.v.i., Microscopy Centre, Vídeňská 1083, 142 20, Prague 4, Czech Republic
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113
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Arias Escayola D, Neugebauer KM. Dynamics and Function of Nuclear Bodies during Embryogenesis. Biochemistry 2018; 57:2462-2469. [PMID: 29473743 DOI: 10.1021/acs.biochem.7b01262] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Nuclear bodies are RNA-rich membraneless organelles in the cell nucleus that concentrate specific sets of nuclear proteins and RNA-protein complexes. Nuclear bodies such as the nucleolus, Cajal body (CB), and the histone locus body (HLB) concentrate factors required for nuclear steps of RNA processing. Formation of these nuclear bodies occurs on genomic loci and is frequently associated with active sites of transcription. Whether nuclear body formation is dependent on a particular gene element, an active process such as transcription, or the nascent RNA present at gene loci is a topic of debate. Recently, this question has been addressed through studies in model organisms and their embryos. The switch from maternally provided RNA and protein to zygotic gene products in early embryos has been well characterized in a variety of organisms. This process, termed maternal-to-zygotic transition, provides an excellent model for studying formation of nuclear bodies before, during, and after the transcriptional activation of the zygotic genome. Here, we review findings in embryos that reveal key principles in the study of the formation and function of nucleoli, CBs, and HLBs. We propose that while particular gene elements may contribute to formation of these nuclear bodies, active transcription promotes maturation of nuclear bodies and efficient RNA processing within them.
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Affiliation(s)
- Dahyana Arias Escayola
- Molecular Biophysics and Biochemistry , Yale University , New Haven , Connecticut 06520-8114 , United States
| | - Karla M Neugebauer
- Molecular Biophysics and Biochemistry , Yale University , New Haven , Connecticut 06520-8114 , United States
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114
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Shin Y, Brangwynne CP. Liquid phase condensation in cell physiology and disease. Science 2018; 357:357/6357/eaaf4382. [PMID: 28935776 DOI: 10.1126/science.aaf4382] [Citation(s) in RCA: 2184] [Impact Index Per Article: 364.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Phase transitions are ubiquitous in nonliving matter, and recent discoveries have shown that they also play a key role within living cells. Intracellular liquid-liquid phase separation is thought to drive the formation of condensed liquid-like droplets of protein, RNA, and other biomolecules, which form in the absence of a delimiting membrane. Recent studies have elucidated many aspects of the molecular interactions underlying the formation of these remarkable and ubiquitous droplets and the way in which such interactions dictate their material properties, composition, and phase behavior. Here, we review these exciting developments and highlight key remaining challenges, particularly the ability of liquid condensates to both facilitate and respond to biological function and how their metastability may underlie devastating protein aggregation diseases.
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Affiliation(s)
- Yongdae Shin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.
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115
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Aryankalayil MJ, Chopra S, Levin J, Eke I, Makinde A, Das S, Shankavaram U, Vanpouille-Box C, Demaria S, Coleman CN. Radiation-Induced Long Noncoding RNAs in a Mouse Model after Whole-Body Irradiation. Radiat Res 2018; 189:251-263. [PMID: 29309266 PMCID: PMC5967844 DOI: 10.1667/rr14891.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Long noncoding RNAs (lncRNAs) are emerging as key molecules in regulating many biological processes and have been implicated in development and disease pathogenesis. Biomarkers of cancer and normal tissue response to treatment are of great interest in precision medicine, as well as in public health and medical management, such as for assessment of radiation injury after an accidental or intentional exposure. Circulating and functional RNAs, including microRNAs (miRNAs) and lncRNAs, in whole blood and other body fluids are potential valuable candidates as biomarkers. Early prediction of possible acute, intermediate and delayed effects of radiation exposure enables timely therapeutic interventions. To address whether long noncoding RNAs (lncRNAs) could serve as biomarkers for radiation biodosimetry we performed whole genome transcriptome analysis in a mouse model after whole-body irradiation. Differential lncRNA expression patterns were evaluated at 16, 24 and 48 h postirradiation in total RNA isolated from whole blood of mice exposed to 1, 2, 4, 8 and 12 Gy of X rays. Sham-irradiated animals served as controls. Significant alterations in the expression patterns of lncRNAs were observed after different radiation doses at the various time points. We identified several radiation-induced lncRNAs known for DNA damage response as well as immune response. Long noncoding RNA targets of tumor protein 53 (P53), Trp53cor1, Dino, Pvt1 and Tug1 and an upstream regulator of p53, Meg3, were altered in response to radiation. Gm14005 ( Morrbid) and Tmevpg1 were regulated by radiation across all time points and doses. These two lncRNAs have important potential as blood-based radiation biomarkers; Gm14005 ( Morrbid) has recently been shown to play a key role in inflammatory response, while Tmevpg1 has been implicated in the regulation of interferon gamma. Precise molecular biomarkers, likely involving a diverse group of inducible molecules, will not only enable the development and effective use of medical countermeasures but may also be used to detect and circumvent or mitigate normal tissue injury in cancer radiotherapy.
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Affiliation(s)
| | - Sunita Chopra
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
| | - Joel Levin
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
| | - Iris Eke
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
| | - Adeola Makinde
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
| | - Shaoli Das
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
| | - Uma Shankavaram
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
| | | | - Sandra Demaria
- Department of Radiation Oncology, Weill Cornell Medicine, New York, New York
| | - C. Norman Coleman
- Radiation Oncology Branch, Center for Cancer Research, NMional Cancer Institute, Bethesda, Maryland
- Radiation Research Progrnm, National Cancer Institute, National Institutes of Health, Rockville, Maryland
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116
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Zhang B, Mao YS, Diermeier SD, Novikova IV, Nawrocki EP, Jones TA, Lazar Z, Tung CS, Luo W, Eddy SR, Sanbonmatsu KY, Spector DL. Identification and Characterization of a Class of MALAT1-like Genomic Loci. Cell Rep 2018; 19:1723-1738. [PMID: 28538188 DOI: 10.1016/j.celrep.2017.05.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/27/2016] [Accepted: 04/28/2017] [Indexed: 02/09/2023] Open
Abstract
The MALAT1 (Metastasis-Associated Lung Adenocarcinoma Transcript 1) gene encodes a noncoding RNA that is processed into a long nuclear retained transcript (MALAT1) and a small cytoplasmic tRNA-like transcript (mascRNA). Using an RNA sequence- and structure-based covariance model, we identified more than 130 genomic loci in vertebrate genomes containing the MALAT1 3' end triple-helix structure and its immediate downstream tRNA-like structure, including 44 in the green lizard Anolis carolinensis. Structural and computational analyses revealed a co-occurrence of components of the 3' end module. MALAT1-like genes in Anolis carolinensis are highly expressed in adult testis, thus we named them testis-abundant long noncoding RNAs (tancRNAs). MALAT1-like loci also produce multiple small RNA species, including PIWI-interacting RNAs (piRNAs), from the antisense strand. The 3' ends of tancRNAs serve as potential targets for the PIWI-piRNA complex. Thus, we have identified an evolutionarily conserved class of long noncoding RNAs (lncRNAs) with similar structural constraints, post-transcriptional processing, and subcellular localization and a distinct function in spermatocytes.
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Affiliation(s)
- Bin Zhang
- Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, NY 11724, USA; Department of Pathology and Laboratory Medicine, Department of Pediatrics, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
| | - Yuntao S Mao
- Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Sarah D Diermeier
- Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Irina V Novikova
- Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, USA; Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, MS K710 Los Alamos, NM 87545, USA
| | - Eric P Nawrocki
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, VA 20147, USA; National Center for Biotechnology Information, U.S. National Library of Medicine, Bethesda, MD 20894, USA
| | - Tom A Jones
- Howard Hughes Medical Institute, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | - Zsolt Lazar
- Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, NY 11724, USA
| | - Chang-Shung Tung
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, MS K710 Los Alamos, NM 87545, USA
| | - Weijun Luo
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
| | - Sean R Eddy
- Howard Hughes Medical Institute, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, MS K710 Los Alamos, NM 87545, USA
| | - David L Spector
- Cold Spring Harbor Laboratory, One Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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117
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Kucherenko MM, Shcherbata HR. miRNA targeting and alternative splicing in the stress response - events hosted by membrane-less compartments. J Cell Sci 2018; 131:131/4/jcs202002. [PMID: 29444950 DOI: 10.1242/jcs.202002] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Stress can be temporary or chronic, and mild or acute. Depending on its extent and severity, cells either alter their metabolism, and adopt a new state, or die. Fluctuations in environmental conditions occur frequently, and such stress disturbs cellular homeostasis, but in general, stresses are reversible and last only a short time. There is increasing evidence that regulation of gene expression in response to temporal stress happens post-transcriptionally in specialized subcellular membrane-less compartments called ribonucleoprotein (RNP) granules. RNP granules assemble through a concentration-dependent liquid-liquid phase separation of RNA-binding proteins that contain low-complexity sequence domains (LCDs). Interestingly, many factors that regulate microRNA (miRNA) biogenesis and alternative splicing are RNA-binding proteins that contain LCDs and localize to stress-induced liquid-like compartments. Consequently, gene silencing through miRNAs and alternative splicing of pre-mRNAs are emerging as crucial post-transcriptional mechanisms that function on a genome-wide scale to regulate the cellular stress response. In this Review, we describe the interplay between these two post-transcriptional processes that occur in liquid-like compartments as an adaptive cellular response to stress.
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Affiliation(s)
- Mariya M Kucherenko
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen, Germany
| | - Halyna R Shcherbata
- Max Planck Research Group of Gene Expression and Signaling, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Goettingen, Germany
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118
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Mobilization of a splicing factor through a nuclear kinase-kinase complex. Biochem J 2018; 475:677-690. [PMID: 29335301 DOI: 10.1042/bcj20170672] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/09/2018] [Accepted: 01/12/2018] [Indexed: 12/17/2022]
Abstract
The splicing of mRNA is dependent on serine-arginine (SR) proteins that are mobilized from membrane-free, nuclear speckles to the nucleoplasm by the Cdc2-like kinases (CLKs). This movement is critical for SR protein-dependent assembly of the macromolecular spliceosome. Although CLK1 facilitates such trafficking through the phosphorylation of serine-proline dipeptides in the prototype SR protein SRSF1, an unrelated enzyme known as SR protein kinase 1 (SRPK1) performs the same function but does not efficiently modify these dipeptides in SRSF1. We now show that the ability of SRPK1 to mobilize SRSF1 from speckles to the nucleoplasm is dependent on active CLK1. Diffusion from speckles is promoted by the formation of an SRPK1-CLK1 complex that facilitates dissociation of SRSF1 from CLK1 and enhances the phosphorylation of several serine-proline dipeptides in this SR protein. Down-regulation of either kinase blocks EGF-stimulated mobilization of nuclear SRSF1. These findings establish a signaling pathway that connects SRPKs to SR protein activation through the associated CLK family of kinases.
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119
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Chujo T, Hirose T. Nuclear Bodies Built on Architectural Long Noncoding RNAs: Unifying Principles of Their Construction and Function. Mol Cells 2017; 40:889-896. [PMID: 29276943 PMCID: PMC5750707 DOI: 10.14348/molcells.2017.0263] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/20/2017] [Accepted: 11/20/2017] [Indexed: 11/27/2022] Open
Abstract
Nuclear bodies are subnuclear, spheroidal, and membraneless compartments that concentrate specific proteins and/or RNAs. They serve as sites of biogenesis, storage, and sequestration of specific RNAs, proteins, or ribonucleoprotein complexes. Recent studies reveal that a subset of nuclear bodies in various eukaryotic organisms is constructed using architectural long noncoding RNAs (arcRNAs). Here, we describe the unifying mechanistic principles of the construction and function of these bodies, especially focusing on liquid-liquid phase separation induced by architectural molecules that form multiple weakly adhesive interactions. We also discuss three possible advantages of using arcRNAs rather than architectural proteins to build the bodies: position-specificity, rapidity, and economy in sequestering nucleic acid-binding proteins. Moreover, we introduce two recently devised methods to discover novel arcRNA-constructed bodies; one that focuses on the RNase-sensitivity of these bodies, and another that focuses on "semi-extractability" of arcRNAs.
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Affiliation(s)
- Takeshi Chujo
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815,
Japan
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815,
Japan
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120
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Fernandez-Vidal A, Vignard J, Mirey G. Around and beyond 53BP1 Nuclear Bodies. Int J Mol Sci 2017; 18:ijms18122611. [PMID: 29206178 PMCID: PMC5751214 DOI: 10.3390/ijms18122611] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 11/27/2017] [Accepted: 12/01/2017] [Indexed: 12/17/2022] Open
Abstract
Within the nucleus, sub-nuclear domains define territories where specific functions occur. Nuclear bodies (NBs) are dynamic structures that concentrate nuclear factors and that can be observed microscopically. Recently, NBs containing the p53 binding protein 1 (53BP1), a key component of the DNA damage response, were defined. Interestingly, 53BP1 NBs are visualized during G1 phase, in daughter cells, while DNA damage was generated in mother cells and not properly processed. Unlike most NBs involved in transcriptional processes, replication has proven to be key for 53BP1 NBs, with replication stress leading to the formation of these large chromatin domains in daughter cells. In this review, we expose the composition and organization of 53BP1 NBs and focus on recent findings regarding their regulation and dynamics. We then concentrate on the importance of the replication stress, examine the relation of 53BP1 NBs with DNA damage and discuss their dysfunction.
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Affiliation(s)
- Anne Fernandez-Vidal
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Julien Vignard
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
| | - Gladys Mirey
- Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INP-Purpan, UPS, 31027 Toulouse, France.
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121
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Schütz S, Nöldeke ER, Sprangers R. A synergistic network of interactions promotes the formation of in vitro processing bodies and protects mRNA against decapping. Nucleic Acids Res 2017; 45:6911-6922. [PMID: 28472520 PMCID: PMC5499654 DOI: 10.1093/nar/gkx353] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 04/20/2017] [Indexed: 01/25/2023] Open
Abstract
Cellular liquid-liquid phase separation (LLPS) results in the formation of dynamic granules that play an important role in many biological processes. On a molecular level, the clustering of proteins into a confined space results from an indefinite network of intermolecular interactions. Here, we introduce and exploit a novel high-throughput bottom-up approach to study how the interactions between RNA, the Dcp1:Dcp2 mRNA decapping complex and the scaffolding proteins Edc3 and Pdc1 result in the formation of processing bodies. We find that the LLPS boundaries are close to physiological concentrations upon inclusion of multiple proteins and RNA. Within in vitro processing bodies the RNA is protected against endonucleolytic cleavage and the mRNA decapping activity is reduced, which argues for a role of processing bodies in temporary mRNA storage. Interestingly, the intrinsically disordered region (IDR) in the Edc3 protein emerges as a central hub for interactions with both RNA and mRNA decapping factors. In addition, the Edc3 IDR plays a role in the formation of irreversible protein aggregates that are potentially detrimental for cellular homeostasis. In summary, our data reveal insights into the mechanisms that lead to cellular LLPS and into the way this influences enzymatic activity.
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Affiliation(s)
- Stefan Schütz
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Erik R Nöldeke
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Remco Sprangers
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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122
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Galganski L, Urbanek MO, Krzyzosiak WJ. Nuclear speckles: molecular organization, biological function and role in disease. Nucleic Acids Res 2017; 45:10350-10368. [PMID: 28977640 PMCID: PMC5737799 DOI: 10.1093/nar/gkx759] [Citation(s) in RCA: 285] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/18/2017] [Indexed: 12/13/2022] Open
Abstract
The nucleoplasm is not homogenous; it consists of many types of nuclear bodies, also known as nuclear domains or nuclear subcompartments. These self-organizing structures gather machinery involved in various nuclear activities. Nuclear speckles (NSs) or splicing speckles, also called interchromatin granule clusters, were discovered as sites for splicing factor storage and modification. Further studies on transcription and mRNA maturation and export revealed a more general role for splicing speckles in RNA metabolism. Here, we discuss the functional implications of the localization of numerous proteins crucial for epigenetic regulation, chromatin organization, DNA repair and RNA modification to nuclear speckles. We highlight recent advances suggesting that NSs facilitate integrated regulation of gene expression. In addition, we consider the influence of abundant regulatory and signaling proteins, i.e. protein kinases and proteins involved in protein ubiquitination, phosphoinositide signaling and nucleoskeletal organization, on pre-mRNA synthesis and maturation. While many of these regulatory proteins act within NSs, direct evidence for mRNA metabolism events occurring in NSs is still lacking. NSs contribute to numerous human diseases, including cancers and viral infections. In addition, recent data have demonstrated close relationships between these structures and the development of neurological disorders.
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Affiliation(s)
- Lukasz Galganski
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Martyna O Urbanek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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123
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Brickner J. Genetic and epigenetic control of the spatial organization of the genome. Mol Biol Cell 2017; 28:364-369. [PMID: 28137949 PMCID: PMC5341720 DOI: 10.1091/mbc.e16-03-0149] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/23/2016] [Accepted: 11/29/2016] [Indexed: 11/11/2022] Open
Abstract
Eukaryotic genomes are spatially organized within the nucleus by chromosome folding, interchromosomal contacts, and interaction with nuclear structures. This spatial organization is observed in diverse organisms and both reflects and contributes to gene expression and differentiation. This leads to the notion that the arrangement of the genome within the nucleus has been shaped and conserved through evolutionary processes and likely plays an adaptive function. Both DNA-binding proteins and changes in chromatin structure influence the positioning of genes and larger domains within the nucleus. This suggests that the spatial organization of the genome can be genetically encoded by binding sites for DNA-binding proteins and can also involve changes in chromatin structure, potentially through nongenetic mechanisms. Here I briefly discuss the results that support these ideas and their implications for how genomes encode spatial organization.
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Affiliation(s)
- Jason Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60201
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124
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Huang GW, Zhang YL, Liao LD, Li EM, Xu LY. Natural antisense transcript TPM1-AS regulates the alternative splicing of tropomyosin I through an interaction with RNA-binding motif protein 4. Int J Biochem Cell Biol 2017; 90:59-67. [PMID: 28754317 DOI: 10.1016/j.biocel.2017.07.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/17/2017] [Accepted: 07/24/2017] [Indexed: 02/05/2023]
Abstract
LncRNAs play a vital role in alternative splicing of target genes. However, the mechanisms underlying lncRNAs involvement in splicing are poorly understood. In the present study, we identified a previously uncharacterized lncRNA, which is denoted as TPM1-AS, is reverse-transcribed from the fourth intronic region of the tropomyosin I (TPM1). In situ hybridization and RNA immunoprecipitation assays demonstrated that TPM1-AS was located in the nucleus and interacted with RNA-binding motif protein 4 (RBM4) in human esophageal cancer cells. TPM1-AS overexpression or RBM4 knockdown decreased endogenous exon 2a expression of TPM1, resulting in specifically down-regulation of TPM1variant V2 and V7 in human esophageal cancer cells. Mechanismly, the interaction of TPM1-AS with RBM4 hindered binding of RBM4 to TPM1 pre-mRNA and inhibited RBM4 to promote endogenous exon 2a inclusion of TPM1. Importantly, overexpression of TPM1-AS inhibited migration and filopodium formation, whereas TPM1variant V2 and V7 promoted these behaviors of human esophageal cancer cells. Taken together, the results suggest that a natural antisense TPM1-AS regulates the alternative splicing of TPM1 through an interaction with RBM4 and involves in TPM1-mediated filopodium formation and migration of cancer cells.
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Affiliation(s)
- Guo-Wei Huang
- Institute of Oncologic Pathology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China; The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou, Guangdong, 515041, PR China; Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China
| | - Ying-Li Zhang
- Institute of Oncologic Pathology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China; Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China
| | - Lian-Di Liao
- Institute of Oncologic Pathology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China; The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou, Guangdong, 515041, PR China
| | - En-Min Li
- The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou, Guangdong, 515041, PR China; Department of Biochemistry and Molecular Biology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China.
| | - Li-Yan Xu
- Institute of Oncologic Pathology, Shantou University Medical College, Shantou, Guangdong, 515041, PR China; The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou, Guangdong, 515041, PR China.
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125
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Shih JW, Kung HJ. Long non-coding RNA and tumor hypoxia: new players ushered toward an old arena. J Biomed Sci 2017; 24:53. [PMID: 28789687 PMCID: PMC5547530 DOI: 10.1186/s12929-017-0358-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/25/2017] [Indexed: 01/17/2023] Open
Abstract
Hypoxia is a classic feature of the tumor microenvironment with a profound impact on cancer progression and therapeutic response. Activation of complex hypoxia pathways orchestrated by the transcription factor HIF (hypoxia-inducible factor) contributes to aggressive phenotypes and metastasis in numerous cancers. Over the past few decades, exponentially growing research indicated the importance of the non-coding genome in hypoxic tumor regions. Recently, key roles of long non coding RNAs (lncRNAs) in hypoxia-driven cancer progression have begun to emerge. These hypoxia-responsive lncRNAs (HRLs) play pivotal roles in regulating hypoxic gene expression at chromatic, transcriptional, and post-transcriptional levels by acting as effectors of the indirect response to HIF or direct modulators of the HIF-transcriptional cascade. Notably, the aberrant expression of HRLs significantly correlates with poor outcomes in cancer patients, showing promise for future utility as a tumor marker or therapeutic target. Here we address the latest advances made toward understanding the functional relevance of HRLs, the involvement of these transcripts in hypoxia response and the underlying action mechanisms, highlighting their specific roles in HIF-1 signaling regulation and hypoxia-associated malignant transformation.
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Affiliation(s)
- Jing-Wen Shih
- Ph.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, 110, Taiwan. .,Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, 110, Taiwan. .,Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, 110, Taiwan.
| | - Hsing-Jien Kung
- Ph.D. Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, 110, Taiwan.,Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, 110, Taiwan.,Department of Biochemistry and Molecular Medicine, Comprehensive Cancer Center, University of California at Davis, Sacramento, CA, 95817, USA.,Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, 350, Taiwan
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126
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Schmitt AM, Chang HY. Long Noncoding RNAs: At the Intersection of Cancer and Chromatin Biology. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a026492. [PMID: 28193769 DOI: 10.1101/cshperspect.a026492] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although only 2% of the genome encodes protein, RNA is transcribed from the majority of the genetic sequence, suggesting a massive degree of cellular functionality is programmed in the noncoding genome. The mammalian genome contains tens of thousands of long noncoding RNAs (lncRNAs), many of which occur at disease-associated loci or are specifically expressed in cancer. Although the vast majority of lncRNAs have no known function, recurring molecular mechanisms for lncRNAs are now being observed in chromatin regulation and cancer pathways and emerging technologies are now providing tools to interrogate lncRNA molecular interactions and determine function of these abundant cellular macromolecules.
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Affiliation(s)
- Adam M Schmitt
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305
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127
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Pankert T, Jegou T, Caudron-Herger M, Rippe K. Tethering RNA to chromatin for fluorescence microscopy based analysis of nuclear organization. Methods 2017; 123:89-101. [DOI: 10.1016/j.ymeth.2017.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/23/2017] [Accepted: 01/30/2017] [Indexed: 12/22/2022] Open
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128
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Sawyer IA, Dundr M. Chromatin loops and causality loops: the influence of RNA upon spatial nuclear architecture. Chromosoma 2017; 126:541-557. [PMID: 28593374 DOI: 10.1007/s00412-017-0632-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 01/18/2023]
Abstract
An intrinsic and essential trait exhibited by cells is the properly coordinated and integrated regulation of an astoundingly large number of simultaneous molecular decisions and reactions to maintain biochemical homeostasis. This is especially true inside the cell nucleus, where the recognition of DNA and RNA by a vast range of nucleic acid-interacting proteins organizes gene expression patterns. However, this dynamic system is not regulated by simple "on" or "off" signals. Instead, transcription factor and RNA polymerase recruitment to DNA are influenced by the local chromatin and epigenetic environment, a gene's relative position within the nucleus and the action of noncoding RNAs. In addition, major phase-separated structural features of the nucleus, such as nucleoli and paraspeckles, assemble in direct response to specific transcriptional activities and, in turn, influence global genomic function. Currently, the interpretation of these data is trapped in a causality dilemma reminiscent of the "chicken and the egg" paradox as it is unclear whether changes in nuclear architecture promote RNA function or vice versa. Here, we review recent advances that suggest a complex and interdependent interaction network between gene expression, chromatin topology, and noncoding RNA function. We also discuss the functional links between these essential nuclear processes from the nanoscale (gene looping) to the macroscale (sub-nuclear gene positioning and nuclear body function) and briefly highlight some of the challenges that researchers may encounter when studying these phenomena.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Miroslav Dundr
- Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA.
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129
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Love AJ, Yu C, Petukhova NV, Kalinina NO, Chen J, Taliansky ME. Cajal bodies and their role in plant stress and disease responses. RNA Biol 2017; 14:779-790. [PMID: 27726481 PMCID: PMC5519230 DOI: 10.1080/15476286.2016.1243650] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 09/19/2016] [Accepted: 09/27/2016] [Indexed: 12/11/2022] Open
Abstract
Cajal bodies (CBs) are distinct sub-nuclear structures that are present in eukaryotic living cells and are often associated with the nucleolus. CBs play important roles in RNA metabolism and formation of RNPs involved in transcription, splicing, ribosome biogenesis, and telomere maintenance. Besides these primary roles, CBs appear to be involved in additional functions that may not be directly related to RNA metabolism and RNP biogenesis. In this review, we assess possible roles of plant CBs in RNA regulatory pathways such as nonsense-mediated mRNA decay and RNA silencing. We also summarize recent progress and discuss new non-canonical functions of plant CBs in responses to stress and disease. It is hypothesized that CBs can regulate these responses via their interaction with poly(ADP ribose)polymerase (PARP), which is known to play an important role in various physiological processes including responses to biotic and abiotic stresses. It is suggested that CBs and their components modify PARP activities and functions.
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Affiliation(s)
- Andrew J. Love
- Cell and Molecular Sciences, James Hutton Institute, Invergowrie, Dundee, UK
| | - Chulang Yu
- State Key Laboratory Breeding Base for Sustainable Pest and Disease Control, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | | | - Natalia O. Kalinina
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow, Russia
| | - Jianping Chen
- State Key Laboratory Breeding Base for Sustainable Pest and Disease Control, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Michael E. Taliansky
- Cell and Molecular Sciences, James Hutton Institute, Invergowrie, Dundee, UK
- State Key Laboratory Breeding Base for Sustainable Pest and Disease Control, Key Laboratory of Biotechnology in Plant Protection of MOA and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
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130
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Sawyer IA, Hager GL, Dundr M. Specific genomic cues regulate Cajal body assembly. RNA Biol 2017; 14:791-803. [PMID: 27715441 PMCID: PMC5519236 DOI: 10.1080/15476286.2016.1243648] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/06/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023] Open
Abstract
The assembly of specialized sub-nuclear microenvironments known as nuclear bodies (NBs) is important for promoting efficient nuclear function. In particular, the Cajal body (CB), a prominent NB that facilitates spliceosomal snRNP biogenesis, assembles in response to genomic cues. Here, we detail the factors that regulate CB assembly and structural maintenance. These include the importance of transcription at nucleating gene loci, the grouping of these genes on human chromosomes 1, 6 and 17, as well as cell cycle and biochemical regulation of CB protein function. We also speculate on the correlation between CB formation and RNA splicing levels in neurons and cancer. The timing and location of these specific molecular events is critical to CB assembly and its contribution to genome function. However, further work is required to explore the emerging biophysical characteristics of CB assembly and the impact upon subsequent genome reorganization.
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Affiliation(s)
- Iain A. Sawyer
- Department of Cell Biology, Rosalind Franklin University of Medicine & Science, Chicago Medical School, North Chicago, IL, USA
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Gordon L. Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Miroslav Dundr
- Department of Cell Biology, Rosalind Franklin University of Medicine & Science, Chicago Medical School, North Chicago, IL, USA
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131
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Staněk D, Fox AH. Nuclear bodies: news insights into structure and function. Curr Opin Cell Biol 2017; 46:94-101. [PMID: 28577509 DOI: 10.1016/j.ceb.2017.05.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 04/20/2017] [Accepted: 05/10/2017] [Indexed: 02/07/2023]
Abstract
The cell nucleus contains a number of different dynamic bodies that are variously composed of proteins and generally, but not always, specific RNA molecules. Recent studies have revealed new understanding about nuclear body formation and function in different aspects of nuclear metabolism. Here, we focus on findings describing the role of nuclear bodies in the biogenesis of specific ribonucleoprotein complexes, processing of key mRNAs, and subnuclear sequestration of protein factors. We highlight how nuclear bodies are involved in stress responses, innate immunity and tumorigenesis. We further review organization of nuclear bodies and principles that govern their assembly, highlighting the pivotal role of scaffolding noncoding RNAs, and liquid-liquid phase separation, which are transforming our picture of nuclear body formation.
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Affiliation(s)
- David Staněk
- Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Archa H Fox
- School of Human Sciences and Molecular Sciences, The University of Western Australia and Harry Perkins Institute of Medical Research, Centre for Medical Research, The University of Western Australia, Crawley, 6009 Western Australia, Australia.
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132
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Caudron-Herger M, Pankert T, Rippe K. Regulation of nucleolus assembly by non-coding RNA polymerase II transcripts. Nucleus 2017; 7:308-18. [PMID: 27416361 DOI: 10.1080/19491034.2016.1190890] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The nucleolus is a nuclear subcompartment for tightly regulated rRNA production and ribosome subunit biogenesis. It also acts as a cellular stress sensor and can release enriched factors in response to cellular stimuli. Accordingly, the content and structure of the nucleolus change dynamically, which is particularly evident during cell cycle progression: the nucleolus completely disassembles during mitosis and reassembles in interphase. Although the mechanisms that drive nucleolar (re)organization have been the subject of a number of studies, they are only partly understood. Recently, we identified Alu element-containing RNA polymerase II transcripts (aluRNAs) as important for nucleolar structure and rRNA synthesis. Integrating these findings with studies on the liquid droplet-like nature of the nucleolus leads us to propose a model on how RNA polymerase II transcripts could regulate the assembly of the nucleolus in response to external stimuli and during cell cycle progression.
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Affiliation(s)
- Maïwen Caudron-Herger
- a RNA Biology and Cancer, German Cancer Research Center (DKFZ) , Heidelberg , Germany
| | - Teresa Pankert
- b Genome Organization & Function, German Cancer Research Center (DKFZ) and BioQuant Center , Heidelberg , Germany
| | - Karsten Rippe
- b Genome Organization & Function, German Cancer Research Center (DKFZ) and BioQuant Center , Heidelberg , Germany
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133
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Chujo T, Yamazaki T, Kawaguchi T, Kurosaka S, Takumi T, Nakagawa S, Hirose T. Unusual semi-extractability as a hallmark of nuclear body-associated architectural noncoding RNAs. EMBO J 2017; 36:1447-1462. [PMID: 28404604 PMCID: PMC5430218 DOI: 10.15252/embj.201695848] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/02/2017] [Accepted: 03/09/2017] [Indexed: 12/21/2022] Open
Abstract
NEAT1_2 long noncoding RNA (lncRNA) is the molecular scaffold of paraspeckle nuclear bodies. Here, we report an improved RNA extraction method: extensive needle shearing or heating of cell lysate in RNA extraction reagent improved NEAT1_2 extraction by 20-fold (a property we term "semi-extractability"), whereas using a conventional method NEAT1_2 was trapped in the protein phase. The improved extraction method enabled us to estimate that approximately 50 NEAT1_2 molecules are present in a single paraspeckle. Another architectural lncRNA, IGS16, also exhibited similar semi-extractability. A comparison of RNA-seq data from needle-sheared and control samples revealed the existence of multiple semi-extractable RNAs, many of which were localized in subnuclear granule-like structures. The semi-extractability of NEAT1_2 correlated with its association with paraspeckle proteins and required the prion-like domain of the RNA-binding protein FUS This observation suggests that tenacious RNA-protein and protein-protein interactions, which drive nuclear body formation, are responsible for semi-extractability. Our findings provide a foundation for the discovery of the architectural RNAs that constitute nuclear bodies.
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Affiliation(s)
- Takeshi Chujo
- Institute for Genetic Medicine, Hokkaido University, Sapporo Hokkaido, Japan
| | - Tomohiro Yamazaki
- Institute for Genetic Medicine, Hokkaido University, Sapporo Hokkaido, Japan
| | - Tetsuya Kawaguchi
- Institute for Genetic Medicine, Hokkaido University, Sapporo Hokkaido, Japan
| | | | - Toru Takumi
- Brain Science Institute, RIKEN, Wako Saitama, Japan
| | - Shinichi Nakagawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo Hokkaido, Japan
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo Hokkaido, Japan
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134
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Banani SF, Lee HO, Hyman AA, Rosen MK. Biomolecular condensates: organizers of cellular biochemistry. Nat Rev Mol Cell Biol 2017; 18:285-298. [PMID: 28225081 PMCID: PMC7434221 DOI: 10.1038/nrm.2017.7] [Citation(s) in RCA: 3134] [Impact Index Per Article: 447.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Biomolecular condensates are micron-scale compartments in eukaryotic cells that lack surrounding membranes but function to concentrate proteins and nucleic acids. These condensates are involved in diverse processes, including RNA metabolism, ribosome biogenesis, the DNA damage response and signal transduction. Recent studies have shown that liquid-liquid phase separation driven by multivalent macromolecular interactions is an important organizing principle for biomolecular condensates. With this physical framework, it is now possible to explain how the assembly, composition, physical properties and biochemical and cellular functions of these important structures are regulated.
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Affiliation(s)
- Salman F. Banani
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hyun O. Lee
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Anthony A. Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Michael K. Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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135
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Björk P, Wieslander L. Integration of mRNP formation and export. Cell Mol Life Sci 2017; 74:2875-2897. [PMID: 28314893 PMCID: PMC5501912 DOI: 10.1007/s00018-017-2503-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
Expression of protein-coding genes in eukaryotes relies on the coordinated action of many sophisticated molecular machineries. Transcription produces precursor mRNAs (pre-mRNAs) and the active gene provides an environment in which the pre-mRNAs are processed, folded, and assembled into RNA–protein (RNP) complexes. The dynamic pre-mRNPs incorporate the growing transcript, proteins, and the processing machineries, as well as the specific protein marks left after processing that are essential for export and the cytoplasmic fate of the mRNPs. After release from the gene, the mRNPs move by diffusion within the interchromatin compartment, making up pools of mRNPs. Here, splicing and polyadenylation can be completed and the mRNPs recruit the major export receptor NXF1. Export competent mRNPs interact with the nuclear pore complex, leading to export, concomitant with compositional and conformational changes of the mRNPs. We summarize the integrated nuclear processes involved in the formation and export of mRNPs.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Lars Wieslander
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
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136
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Skalska L, Beltran-Nebot M, Ule J, Jenner RG. Regulatory feedback from nascent RNA to chromatin and transcription. Nat Rev Mol Cell Biol 2017; 18:331-337. [PMID: 28270684 DOI: 10.1038/nrm.2017.12] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Transcription and chromatin function are regulated by proteins that bind to DNA, nucleosomes or RNA polymerase II, with specific non-coding RNAs (ncRNAs) functioning to modulate their recruitment or activity. Unlike ncRNAs, nascent pre-mRNA was considered to be primarily a passive player in these processes. In this Opinion article, we describe recently identified interactions between nascent pre-mRNAs and regulatory proteins, highlight commonalities between the functions of nascent pre-mRNA and nascent ncRNA, and propose that both types of RNA have an active role in transcription and chromatin regulation.
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Affiliation(s)
- Lenka Skalska
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Manuel Beltran-Nebot
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Jernej Ule
- Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; and The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Richard G Jenner
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, UK
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137
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Yu X, Li Z, Zheng H, Chan MTV, Wu WKK. NEAT1: A novel cancer-related long non-coding RNA. Cell Prolif 2017; 50. [PMID: 28105699 DOI: 10.1111/cpr.12329] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 12/10/2016] [Indexed: 12/12/2022] Open
Abstract
Aberrant overexpression of the long non-coding RNA NEAT1 (nuclear paraspeckle assembly transcript 1) has been documented in different types of solid tumours, such as lung cancer, oesophageal cancer, colorectal cancer and hepatocellular carcinoma, in which its high levels are associated with poor prognosis. In contrast, NEAT1 is downregulated in acute promyelocytic leukaemia where it promotes leucocyte differentiation. In this review, we provide an overview of current evidence concerning the oncogenic role and potential clinical utilities of NEAT1. Further investigations are warranted to elucidate the upstream and downstream mechanisms of NEAT1 overexpression.
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Affiliation(s)
- Xin Yu
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zheng Li
- Department of Orthopedics Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Heyi Zheng
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Matthew T V Chan
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong
| | - William Ka Kei Wu
- Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Hong Kong.,State Key Laboratory of Digestive Disease and LKS Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong
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138
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Duronio RJ, Marzluff WF. Coordinating cell cycle-regulated histone gene expression through assembly and function of the Histone Locus Body. RNA Biol 2017; 14:726-738. [PMID: 28059623 DOI: 10.1080/15476286.2016.1265198] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Metazoan replication-dependent (RD) histone genes encode the only known cellular mRNAs that are not polyadenylated. These mRNAs end instead in a conserved stem-loop, which is formed by an endonucleolytic cleavage of the pre-mRNA. The genes for all 5 histone proteins are clustered in all metazoans and coordinately regulated with high levels of expression during S phase. Production of histone mRNAs occurs in a nuclear body called the Histone Locus Body (HLB), a subdomain of the nucleus defined by a concentration of factors necessary for histone gene transcription and pre-mRNA processing. These factors include the scaffolding protein NPAT, essential for histone gene transcription, and FLASH and U7 snRNP, both essential for histone pre-mRNA processing. Histone gene expression is activated by Cyclin E/Cdk2-mediated phosphorylation of NPAT at the G1-S transition. The concentration of factors within the HLB couples transcription with pre-mRNA processing, enhancing the efficiency of histone mRNA biosynthesis.
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Affiliation(s)
- Robert J Duronio
- a Department of Biology , University of North Carolina , Chapel Hill , NC , USA.,b Department of Genetics , University of North Carolina , Chapel Hill , NC , USA.,c Integrative Program for Biological and Genome Sciences , University of North Carolina , Chapel Hill , NC , USA.,d Lineberger Comprehensive Cancer Center , University of North Carolina , Chapel Hill , NC , USA
| | - William F Marzluff
- a Department of Biology , University of North Carolina , Chapel Hill , NC , USA.,c Integrative Program for Biological and Genome Sciences , University of North Carolina , Chapel Hill , NC , USA.,d Lineberger Comprehensive Cancer Center , University of North Carolina , Chapel Hill , NC , USA.,e Department of Biochemistry and Biophysics , University of North Carolina , Chapel Hill , NC , USA
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139
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Duffy MF, Tang J, Sumardy F, Nguyen HHT, Selvarajah SA, Josling GA, Day KP, Petter M, Brown GV. Activation and clustering of a Plasmodium falciparum var gene are affected by subtelomeric sequences. FEBS J 2016; 284:237-257. [PMID: 27860263 DOI: 10.1111/febs.13967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 10/12/2016] [Accepted: 11/15/2016] [Indexed: 11/30/2022]
Abstract
The Plasmodium falciparum var multigene family encodes the cytoadhesive, variant antigen PfEMP1. P. falciparum antigenic variation and cytoadhesion specificity are controlled by epigenetic switching between the single, or few, simultaneously expressed var genes. Most var genes are maintained in perinuclear clusters of heterochromatic telomeres. The active var gene(s) occupy a single, perinuclear var expression site. It is unresolved whether the var expression site forms in situ at a telomeric cluster or whether it is an extant compartment to which single chromosomes travel, thus controlling var switching. Here we show that transcription of a var gene did not require decreased colocalisation with clusters of telomeres, supporting var expression site formation in situ. However following recombination within adjacent subtelomeric sequences, the same var gene was persistently activated and did colocalise less with telomeric clusters. Thus, participation in stable, heterochromatic, telomere clusters and var switching are independent but are both affected by subtelomeric sequences. The var expression site colocalised with the euchromatic mark H3K27ac to a greater extent than it did with heterochromatic H3K9me3. H3K27ac was enriched within the active var gene promoter even when the var gene was transiently repressed in mature parasites and thus H3K27ac may contribute to var gene epigenetic memory.
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Affiliation(s)
- Michael F Duffy
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Jingyi Tang
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Fransisca Sumardy
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Hanh H T Nguyen
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Shamista A Selvarajah
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Gabrielle A Josling
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, PA, USA
| | - Karen P Day
- The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Michaela Petter
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Victoria, Australia.,The School of BioSciences, Bio21, The University of Melbourne, Victoria, Australia
| | - Graham V Brown
- The Nossal Institute for Global Health, The University of Melbourne, Victoria, Australia
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140
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Heyn P, Salmonowicz H, Rodenfels J, Neugebauer KM. Activation of transcription enforces the formation of distinct nuclear bodies in zebrafish embryos. RNA Biol 2016; 14:752-760. [PMID: 27858508 DOI: 10.1080/15476286.2016.1255397] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nuclear bodies are cellular compartments that lack lipid bilayers and harbor specific RNAs and proteins. Recent proposals that nuclear bodies form through liquid-liquid phase separation leave the question of how different nuclear bodies maintain their distinct identities unanswered. Here we investigate Cajal bodies (CBs), histone locus bodies (HLBs) and nucleoli - involved in assembly of the splicing machinery, histone mRNA 3' end processing, and rRNA processing, respectively - in the embryos of the zebrafish, Danio rerio. We take advantage of the transcriptional silence of the 1-cell embryo and follow nuclear body appearance as zygotic transcription becomes activated. CBs are present from fertilization onwards, while HLB and nucleolar components formed foci several hours later when histone genes and rDNA became active. HLB formation was blocked by transcription inhibition, suggesting nascent histone transcripts recruit HLB components like U7 snRNP. Surprisingly, we found that U7 base-pairing with nascent histone transcripts was not required for localization to HLBs. Rather, the type of Sm ring assembled on U7 determined its targeting to HLBs or CBs; the spliceosomal Sm ring targeted snRNAs to CBs while the specialized U7 Sm-ring localized to HLBs, demonstrating the contribution of protein constituents to the distinction among nuclear bodies. Thus, nucleolar, HLB, and CB components can mix in early embryogenesis when transcription is naturally or artificially silenced. These data support a model in which transcription of specific gene loci nucleates nuclear body components with high specificity and fidelity to perform distinct regulatory functions.
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Affiliation(s)
- Patricia Heyn
- a Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , Germany
| | - Hanna Salmonowicz
- a Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , Germany
| | - Jonathan Rodenfels
- b Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , CT , USA
| | - Karla M Neugebauer
- b Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , CT , USA
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141
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Musinova YR, Lisitsyna OM, Sorokin DV, Arifulin EA, Smirnova TA, Zinovkin RA, Potashnikova DM, Vassetzky YS, Sheval EV. RNA-dependent disassembly of nuclear bodies. J Cell Sci 2016; 129:4509-4520. [PMID: 27875271 DOI: 10.1242/jcs.189142] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 11/02/2016] [Indexed: 12/17/2022] Open
Abstract
Nuclear bodies are membraneless organelles that play important roles in genome functioning. A specific type of nuclear bodies known as interphase prenucleolar bodies (iPNBs) are formed in the nucleoplasm after hypotonic stress from partially disassembled nucleoli. iPNBs are then disassembled, and the nucleoli are reformed simultaneously. Here, we show that diffusion of B23 molecules (also known as nucleophosmin, NPM1) from iPNBs, but not fusion of iPNBs with the nucleoli, contributes to the transfer of B23 from iPNBs to the nucleoli. Maturation of pre-ribosomal RNAs (rRNAs) and the subsequent outflow of mature rRNAs from iPNBs led to the disassembly of iPNBs. We found that B23 transfer was dependent on the synthesis of pre-rRNA molecules in nucleoli; these pre-rRNA molecules interacted with B23 and led to its accumulation within nucleoli. The transfer of B23 between iPNBs and nucleoli was accomplished through a nucleoplasmic pool of B23, and increased nucleoplasmic B23 content retarded disassembly, whereas B23 depletion accelerated disassembly. Our results suggest that iPNB disassembly and nucleolus assembly might be coupled through RNA-dependent exchange of nucleolar proteins, creating a highly dynamic system with long-distance correlations between spatially distinct processes.
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Affiliation(s)
- Yana R Musinova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia.,LIA1066 French-Russian Joint Cancer Research Laboratory, Villejuif 94805, France
| | - Olga M Lisitsyna
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
| | - Dmitry V Sorokin
- Centre for Biomedical Image Analysis, Faculty of Informatics, Masaryk University, Botanická 68a, Brno 602 00, Czech Republic.,Laboratory of Mathematical Methods of Image Processing, Faculty of Computational Mathematics and Cybernetics, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
| | - Eugene A Arifulin
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
| | - Tatiana A Smirnova
- Department of Cell Biology and Histology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
| | - Roman A Zinovkin
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
| | - Daria M Potashnikova
- Department of Cell Biology and Histology, Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia
| | - Yegor S Vassetzky
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia.,LIA1066 French-Russian Joint Cancer Research Laboratory, Villejuif 94805, France.,UMR8126, Université Paris-Sud, CNRS, Institut de cancérologie Gustave Roussy, Villejuif 94805, France
| | - Eugene V Sheval
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119992, Russia .,LIA1066 French-Russian Joint Cancer Research Laboratory, Villejuif 94805, France
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142
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Long non-coding RNAs: spatial amplifiers that control nuclear structure and gene expression. Nat Rev Mol Cell Biol 2016; 17:756-770. [DOI: 10.1038/nrm.2016.126] [Citation(s) in RCA: 420] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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143
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Sawyer IA, Sturgill D, Sung MH, Hager GL, Dundr M. Cajal body function in genome organization and transcriptome diversity. Bioessays 2016; 38:1197-1208. [PMID: 27767214 DOI: 10.1002/bies.201600144] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nuclear bodies contribute to non-random organization of the human genome and nuclear function. Using a major prototypical nuclear body, the Cajal body, as an example, we suggest that these structures assemble at specific gene loci located across the genome as a result of high transcriptional activity. Subsequently, target genes are physically clustered in close proximity in Cajal body-containing cells. However, Cajal bodies are observed in only a limited number of human cell types, including neuronal and cancer cells. Ultimately, Cajal body depletion perturbs splicing kinetics by reducing target small nuclear RNA (snRNA) transcription and limiting the levels of spliceosomal snRNPs, including their modification and turnover following each round of RNA splicing. As such, Cajal bodies are capable of shaping the chromatin interaction landscape and the transcriptome by influencing spliceosome kinetics. Future studies should concentrate on characterizing the direct influence of Cajal bodies upon snRNA gene transcriptional dynamics. Also see the video abstract here.
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Affiliation(s)
- Iain A Sawyer
- Department of Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.,Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Myong-Hee Sung
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Gordon L Hager
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Miroslav Dundr
- Department of Cell Biology, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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144
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West JA, Mito M, Kurosaka S, Takumi T, Tanegashima C, Chujo T, Yanaka K, Kingston RE, Hirose T, Bond C, Fox A, Nakagawa S. Structural, super-resolution microscopy analysis of paraspeckle nuclear body organization. J Cell Biol 2016; 214:817-30. [PMID: 27646274 PMCID: PMC5037409 DOI: 10.1083/jcb.201601071] [Citation(s) in RCA: 221] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 08/24/2016] [Indexed: 12/13/2022] Open
Abstract
Paraspeckles are nuclear bodies built on the long noncoding RNA Neat1, which regulates a variety of physiological processes including cancer progression and corpus luteum formation. To obtain further insight into the molecular basis of the function of paraspeckles, we performed fine structural analyses of these nuclear bodies using structural illumination microscopy. Notably, paraspeckle proteins are found within different layers along the radially arranged bundles of Neat1 transcripts, forming a characteristic core-shell spheroidal structure. In cells lacking the RNA binding protein Fus, paraspeckle spheroids are disassembled into smaller particles containing Neat1, which are diffusely distributed in the nucleoplasm. Sequencing analysis of RNAs purified from paraspeckles revealed that AG-rich transcripts associate with Neat1, which are distributed along the shell of the paraspeckle spheroids. We propose that paraspeckles sequester core components inside the spheroids, whereas the outer surface associates with other components in the nucleoplasm to fulfill their function.
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Affiliation(s)
- Jason A West
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Mari Mito
- RNA Biology Laboratory, RIKEN, Wako 351-0198, Japan
| | | | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Chiharu Tanegashima
- Phyloinformatics Unit, RIKEN Center for Life Science Technologies, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Takeshi Chujo
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
| | - Kaori Yanaka
- RNA Biology Laboratory, RIKEN, Wako 351-0198, Japan
| | - Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 Department of Genetics, Harvard Medical School, Boston, MA 02115
| | - Tetsuro Hirose
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
| | - Charles Bond
- School of Chemistry and Biochemistry, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Archa Fox
- School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia 6009, Australia Harry Perkins Institute of Medical Research, Queen Elizabeth II Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Shinichi Nakagawa
- RNA Biology Laboratory, RIKEN, Wako 351-0198, Japan RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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145
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Paraspeckles modulate the intranuclear distribution of paraspeckle-associated Ctn RNA. Sci Rep 2016; 6:34043. [PMID: 27665741 PMCID: PMC5036046 DOI: 10.1038/srep34043] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/07/2016] [Indexed: 01/01/2023] Open
Abstract
Paraspeckles are sub-nuclear domains that are nucleated by long noncoding RNA Neat1. While interaction of protein components of paraspeckles and Neat1 is understood, there is limited information on the interaction of non-structural RNA components with paraspeckles. Here, by varying paraspeckle number and size, we investigate how paraspeckles influence the nuclear organization of their non-structural RNA component Ctn RNA. Our results show that Ctn RNA remains nuclear-retained in the absence of intact paraspeckles, suggesting that they do not regulate nuclear retention of Ctn RNA. In the absence of Neat1, Ctn RNA continues to interact with paraspeckle protein NonO to form residual nuclear foci. In addition, in the absence of Neat1-nucleated paraspeckles, a subset of Ctn RNA localizes to the perinucleolar regions. Concomitant with increase in number of paraspeckles, transcriptional reactivation resulted in increased number of paraspeckle-localized Ctn RNA foci. Similar to Neat1, proteasome inhibition altered the localization of Ctn RNA, where it formed enlarged paraspeckle-like foci. Super-resolution structured illumination microscopic analyses revealed that in paraspeckles, Ctn RNA partially co-localized with Neat1, and displayed a more heterogeneous intra-paraspeckle localization. Collectively, these results show that while paraspeckles do not influence nuclear retention of Ctn RNA, they modulate its intranuclear compartmentalization.
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146
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Abstract
Cajal is commonly regarded as the father of modern neuroscience in recognition of his fundamental work on the structure of the nervous system. But Cajal also made seminal contributions to the knowledge of nuclear structure in the early 1900s, including the discovery of the "accessory body" later renamed "Cajal body" (CB). This important nuclear structure has emerged as a center for the assembly of ribonucleoproteins (RNPs) required for splicing, ribosome biogenesis and telomere maintenance. The modern era of CB research started in the 1990s with the discovery of coilin, now known as a scaffold protein of CBs, and specific probes for small nuclear RNAs (snRNAs). In this review, we summarize what we have learned in the recent decades concerning CBs in post-mitotic neurons, thereby ruling out dynamic changes in CB functions during the cell cycle. We show that CBs are particularly prominent in neurons, where they frequently associate with the nucleolus. Neuronal CBs are transcription-dependent nuclear organelles. Indeed, their number dynamically accommodates to support the high neuronal demand for splicing and ribosome biogenesis required for sustaining metabolic and bioelectrical activity. Mature neurons have canonical CBs enriched in coilin, survival motor neuron protein and snRNPs. Disruption and loss of neuronal CBs associate with severe neuronal dysfunctions in several neurological disorders such as motor neuron diseases. In particular, CB depletion in motor neurons seems to reflect a perturbation of transcription and splicing in spinal muscular atrophy, the most common genetic cause of infant mortality.
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Affiliation(s)
- Miguel Lafarga
- a Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)" , Universidad de Cantabria-IDIVAL , Santander , Spain
| | - Olga Tapia
- a Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)" , Universidad de Cantabria-IDIVAL , Santander , Spain
| | - Ana M Romero
- a Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)" , Universidad de Cantabria-IDIVAL , Santander , Spain
| | - Maria T Berciano
- a Departamento de Anatomía y Biología Celular and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)" , Universidad de Cantabria-IDIVAL , Santander , Spain
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147
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Brickner DG, Sood V, Tutucci E, Coukos R, Viets K, Singer RH, Brickner JH. Subnuclear positioning and interchromosomal clustering of the GAL1-10 locus are controlled by separable, interdependent mechanisms. Mol Biol Cell 2016; 27:2980-93. [PMID: 27489341 PMCID: PMC5042583 DOI: 10.1091/mbc.e16-03-0174] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/27/2016] [Indexed: 01/10/2023] Open
Abstract
“DNA zip codes” control positioning and interchromosomal clustering of GAL1-10 in yeast. However, these two phenomena have distinct molecular mechanisms, requiring different nuclear pore proteins, and are regulated differently by transcription and the cell cycle. On activation, the GAL genes in yeast are targeted to the nuclear periphery through interaction with the nuclear pore complex. Here we identify two cis-acting “DNA zip codes” from the GAL1-10 promoter that are necessary and sufficient to induce repositioning to the nuclear periphery. One of these zip codes, GRS4, is also necessary and sufficient to promote clustering of GAL1-10 alleles. GRS4, and to a lesser extent GRS5, contribute to stronger expression of GAL1 and GAL10 by increasing the fraction of cells that respond to the inducer. The molecular mechanism controlling targeting to the NPC is distinct from the molecular mechanism controlling interchromosomal clustering. Targeting to the nuclear periphery and interaction with the nuclear pore complex are prerequisites for gene clustering. However, once formed, clustering can be maintained in the nucleoplasm, requires distinct nuclear pore proteins, and is regulated differently through the cell cycle. In addition, whereas targeting of genes to the NPC is independent of transcription, interchromosomal clustering requires transcription. These results argue that zip code–dependent gene positioning at the nuclear periphery and interchromosomal clustering represent interdependent phenomena with distinct molecular mechanisms.
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Affiliation(s)
| | - Varun Sood
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Evelina Tutucci
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Robert Coukos
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Kayla Viets
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461 Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147
| | - Jason H Brickner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
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148
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Tomita S, Abdalla MOA, Fujiwara S, Yamamoto T, Iwase H, Nakao M, Saitoh N. Roles of long noncoding RNAs in chromosome domains. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 8. [DOI: 10.1002/wrna.1384] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 06/30/2016] [Accepted: 07/07/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Saori Tomita
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics; Kumamoto University; Kumamoto Japan
- Department of Breast and Endocrine Surgery, Graduate School of Medical Sciences; Kumamoto University; Kumamoto Japan
| | - Mohamed Osama Ali Abdalla
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics; Kumamoto University; Kumamoto Japan
- Department of Clinical Pathology, Faculty of Medicine; Suez Canal University; Ismailia Egypt
| | - Saori Fujiwara
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics; Kumamoto University; Kumamoto Japan
- Department of Breast and Endocrine Surgery, Graduate School of Medical Sciences; Kumamoto University; Kumamoto Japan
| | - Tatsuro Yamamoto
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics; Kumamoto University; Kumamoto Japan
| | - Hirotaka Iwase
- Department of Breast and Endocrine Surgery, Graduate School of Medical Sciences; Kumamoto University; Kumamoto Japan
| | - Mitsuyoshi Nakao
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics; Kumamoto University; Kumamoto Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Agency for Medical Research and Development; Tokyo Japan
| | - Noriko Saitoh
- Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics; Kumamoto University; Kumamoto Japan
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149
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Aguzzi A, Altmeyer M. Phase Separation: Linking Cellular Compartmentalization to Disease. Trends Cell Biol 2016; 26:547-558. [DOI: 10.1016/j.tcb.2016.03.004] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 03/04/2016] [Accepted: 03/08/2016] [Indexed: 12/29/2022]
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150
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Ben-Yishay R, Ashkenazy AJ, Shav-Tal Y. Dynamic Encounters of Genes and Transcripts with the Nuclear Pore. Trends Genet 2016; 32:419-431. [DOI: 10.1016/j.tig.2016.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 04/20/2016] [Indexed: 01/04/2023]
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