1
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Ingram HB, Fox AH. Unveiling the intricacies of paraspeckle formation and function. Curr Opin Cell Biol 2024; 90:102399. [PMID: 39033706 DOI: 10.1016/j.ceb.2024.102399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/19/2024] [Accepted: 06/25/2024] [Indexed: 07/23/2024]
Abstract
Paraspeckle nuclear bodies form when the NEAT1 long noncoding RNA is transcribed and bound by multiple RNA-binding proteins. First described 20 years ago, in recent years a growing appreciation of paraspeckle dynamics has led to new understandings, in both structure and function. Structurally, paraspeckles form via distinct physico-chemical domains arising from the composition of key proteins, recruited to different parts of NEAT1. These domains interact, creating a core-shell structured paraspeckle via microphase separation. Functionally, many environmental, chemical, and mechanical triggers can alter paraspeckle abundance, with important consequences depending on the cell type, developmental stage, and trigger identity. Underpinning these insights are new tools for paraspeckle research, including screening assays, proximity-based identification tools, and RNA processing modulators. A picture is emerging of paraspeckles as gene regulatory condensates in many healthy and disease settings. Critically, however, paraspeckle functional importance is generally most apparent when cells and organisms face external stressors.
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Affiliation(s)
- Hayley B Ingram
- School of Human Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Archa H Fox
- School of Human Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia.
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2
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Chakraborty S, Mishra J, Roy A, Niharika, Manna S, Baral T, Nandi P, Patra S, Patra SK. Liquid-liquid phase separation in subcellular assemblages and signaling pathways: Chromatin modifications induced gene regulation for cellular physiology and functions including carcinogenesis. Biochimie 2024; 223:74-97. [PMID: 38723938 DOI: 10.1016/j.biochi.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/08/2024] [Accepted: 05/04/2024] [Indexed: 05/24/2024]
Abstract
Liquid-liquid phase separation (LLPS) describes many biochemical processes, including hydrogel formation, in the integrity of macromolecular assemblages and existence of membraneless organelles, including ribosome, nucleolus, nuclear speckles, paraspeckles, promyelocytic leukemia (PML) bodies, Cajal bodies (all exert crucial roles in cellular physiology), and evidence are emerging day by day. Also, phase separation is well documented in generation of plasma membrane subdomains and interplay between membranous and membraneless organelles. Intrinsically disordered regions (IDRs) of biopolymers/proteins are the most critical sticking regions that aggravate the formation of such condensates. Remarkably, phase separated condensates are also involved in epigenetic regulation of gene expression, chromatin remodeling, and heterochromatinization. Epigenetic marks on DNA and histones cooperate with RNA-binding proteins through their IDRs to trigger LLPS for facilitating transcription. How phase separation coalesces mutant oncoproteins, orchestrate tumor suppressor genes expression, and facilitated cancer-associated signaling pathways are unravelling. That autophagosome formation and DYRK3-mediated cancer stem cell modification also depend on phase separation is deciphered in part. In view of this, and to linchpin insight into the subcellular membraneless organelle assembly, gene activation and biological reactions catalyzed by enzymes, and the downstream physiological functions, and how all these events are precisely facilitated by LLPS inducing organelle function, epigenetic modulation of gene expression in this scenario, and how it goes awry in cancer progression are summarized and presented in this article.
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Affiliation(s)
- Subhajit Chakraborty
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Jagdish Mishra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Ankan Roy
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Niharika
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Soumen Manna
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Tirthankar Baral
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Piyasa Nandi
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India
| | - Subhajit Patra
- Department of Chemical Engineering, Maulana Azad National Institute of Technology, Bhopal, India
| | - Samir Kumar Patra
- Epigenetics and Cancer Research Laboratory, Biochemistry and Molecular Biology Group, Department of Life Science, National Institute of Technology, Rourkela, India.
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3
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Toya H, Okamatsu-Ogura Y, Yokoi S, Kurihara M, Mito M, Iwasaki S, Hirose T, Nakagawa S. The essential role of architectural noncoding RNA Neat1 in cold-induced beige adipocyte differentiation in mice. RNA (NEW YORK, N.Y.) 2024; 30:1011-1024. [PMID: 38692841 PMCID: PMC11251523 DOI: 10.1261/rna.079972.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/08/2024] [Indexed: 05/03/2024]
Abstract
Neat1 is an architectural RNA that provides the structural basis for nuclear bodies known as paraspeckles. Although the assembly processes by which Neat1 organizes paraspeckle components are well-documented, the physiological functions of Neat1 are not yet fully understood. This is partly because Neat1 knockout (KO) mice, lacking paraspeckles, do not exhibit overt phenotypes under normal laboratory conditions. During our search for conditions that elicit clear phenotypes in Neat1 KO mice, we discovered that the differentiation of beige adipocytes-inducible thermogenic cells that emerge upon cold exposure-is severely impaired in these mutant mice. Neat1_2, the architectural isoform of Neat1, is transiently upregulated during the early stages of beige adipocyte differentiation, coinciding with increased paraspeckle formation. Genes with altered expression during beige adipocyte differentiation typically cluster at specific chromosomal locations, some of which move closer to paraspeckles upon cold exposure. These observations suggest that paraspeckles might coordinate the regulation of these gene clusters by controlling the activity of certain transcriptional condensates that coregulate multiple genes. We propose that our findings highlight a potential role for Neat1 and paraspeckles in modulating chromosomal organization and gene expression, potentially crucial processes for the differentiation of beige adipocytes.
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Affiliation(s)
- Hikaru Toya
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Yuko Okamatsu-Ogura
- Laboratory of Biochemistry, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan
| | - Saori Yokoi
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Misuzu Kurihara
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Mari Mito
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Saitama 351-0198, Japan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Saitama 351-0198, Japan
| | - Tetsuro Hirose
- RNA Biofunction Laboratory, Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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4
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Hu Z, Sun T, Chen W, Nordenskiöld L, Lu L. Refined Bonded Terms in Coarse-Grained Models for Intrinsically Disordered Proteins Improve Backbone Conformations. J Phys Chem B 2024; 128:6492-6508. [PMID: 38950000 DOI: 10.1021/acs.jpcb.4c02823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/03/2024]
Abstract
Coarse-grained models designed for intrinsically disordered proteins and regions (IDP/Rs) usually omit some bonded potentials (e.g., angular and dihedral potentials) as a conventional strategy to enhance backbone flexibility. However, a notable drawback of this approach is the generation of inaccurate backbone conformations. Here, we addressed this problem by introducing residue-specific angular, refined dihedral, and correction map (CMAP) potentials, derived based on the statistics from a customized coil database. These bonded potentials were integrated into the existing Mpipi model, resulting in a new model, denoted as the "Mpipi+" model. Results show that the Mpipi+ model can improve backbone conformations. More importantly, it can markedly improve the secondary structure propensity (SSP) based on the experimental chemical shift and, consequently, succeed in capturing transient secondary structures. Moreover, the Mpipi+ model preserves the liquid-liquid phase separation (LLPS) propensities of IDPs.
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Affiliation(s)
- Zixin Hu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Tiedong Sun
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Wenwen Chen
- UHL no. 05-01, Tan Chin Tuan Wing, Office of the President, University Hall, National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077, Singapore
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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5
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Chauhan G, Bremer A, Dar F, Mittag T, Pappu RV. Crowder titrations enable the quantification of driving forces for macromolecular phase separation. Biophys J 2024; 123:1376-1392. [PMID: 37717144 PMCID: PMC11163301 DOI: 10.1016/j.bpj.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/03/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023] Open
Abstract
Macromolecular solubility is an important contributor to the driving forces for phase separation. Formally, the driving forces in a binary mixture comprising a macromolecule dissolved in a solvent can be quantified in terms of the saturation concentration, which is the threshold macromolecular concentration above which the mixture separates into coexisting dense and dilute phases. In addition, the second virial coefficient, which measures the effective strength of solvent-mediated intermolecular interactions provides direct assessments of solvent quality. The sign and magnitude of second virial coefficients will be governed by a combination of solution conditions and the nature of the macromolecule of interest. Here, we show, using a combination of theory, simulation, and in vitro experiments, that titrations of crowders, providing they are true depletants, can be used to extract the intrinsic driving forces for macromolecular phase separation. This refers to saturation concentrations in the absence of crowders and the second virial coefficients that quantify the magnitude of the incompatibility between macromolecules and the solvent. Our results show how the depletion-mediated attractions afforded by crowders can be leveraged to obtain comparative assessments of macromolecule-specific, intrinsic driving forces for phase separation.
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Affiliation(s)
- Gaurav Chauhan
- Department of Biomedical Engineering and Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Anne Bremer
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Furqan Dar
- Department of Biomedical Engineering and Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biomolecular Condensates, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri.
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6
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Palihati M, Saitoh N. RNA in chromatin organization and nuclear architecture. Curr Opin Genet Dev 2024; 86:102176. [PMID: 38490161 DOI: 10.1016/j.gde.2024.102176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 02/08/2024] [Accepted: 02/11/2024] [Indexed: 03/17/2024]
Abstract
In the cell nucleus, genomic DNA is surrounded by nonmembranous nuclear bodies. This might result from specific regions of the genome being transcribed into long noncoding RNAs (lncRNAs), which tend to remain at the sites of their own transcription. The lncRNAs seed the nuclear bodies by recruiting and concentrating proteins and RNAs, which undergo liquid-liquid-phase separation, and form molecular condensates, the so-called nuclear bodies. These nuclear bodies may provide appropriate environments for gene activation or repression. Notably, lncRNAs also contribute to three-dimensional genome structure by mediating long-range chromatin interactions. In this review, we discuss the mechanisms by which lncRNAs regulate gene expression through shaping chromatin and nuclear architectures. We also explore lncRNAs' potential as a therapeutic target for cancer, because lncRNAs are often expressed in a disease-specific manner.
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Affiliation(s)
- Maierdan Palihati
- Division of Cancer Biology, The Cancer Institute of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of JFCR, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan.
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7
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Zacco E, Broglia L, Kurihara M, Monti M, Gustincich S, Pastore A, Plath K, Nagakawa S, Cerase A, Sanchez de Groot N, Tartaglia GG. RNA: The Unsuspected Conductor in the Orchestra of Macromolecular Crowding. Chem Rev 2024; 124:4734-4777. [PMID: 38579177 PMCID: PMC11046439 DOI: 10.1021/acs.chemrev.3c00575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 01/12/2024] [Accepted: 01/18/2024] [Indexed: 04/07/2024]
Abstract
This comprehensive Review delves into the chemical principles governing RNA-mediated crowding events, commonly referred to as granules or biological condensates. We explore the pivotal role played by RNA sequence, structure, and chemical modifications in these processes, uncovering their correlation with crowding phenomena under physiological conditions. Additionally, we investigate instances where crowding deviates from its intended function, leading to pathological consequences. By deepening our understanding of the delicate balance that governs molecular crowding driven by RNA and its implications for cellular homeostasis, we aim to shed light on this intriguing area of research. Our exploration extends to the methodologies employed to decipher the composition and structural intricacies of RNA granules, offering a comprehensive overview of the techniques used to characterize them, including relevant computational approaches. Through two detailed examples highlighting the significance of noncoding RNAs, NEAT1 and XIST, in the formation of phase-separated assemblies and their influence on the cellular landscape, we emphasize their crucial role in cellular organization and function. By elucidating the chemical underpinnings of RNA-mediated molecular crowding, investigating the role of modifications, structures, and composition of RNA granules, and exploring both physiological and aberrant phase separation phenomena, this Review provides a multifaceted understanding of the intriguing world of RNA-mediated biological condensates.
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Affiliation(s)
- Elsa Zacco
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Laura Broglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Misuzu Kurihara
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Michele Monti
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Stefano Gustincich
- Central
RNA Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
| | - Annalisa Pastore
- UK
Dementia Research Institute at the Maurice Wohl Institute of King’s
College London, London SE5 9RT, U.K.
| | - Kathrin Plath
- Department
of Biological Chemistry, David Geffen School
of Medicine at the University of California Los Angeles, Los Angeles, California 90095, United States
| | - Shinichi Nagakawa
- RNA
Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Andrea Cerase
- Blizard
Institute,
Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, U.K.
- Unit
of Cell and developmental Biology, Department of Biology, Università di Pisa, 56123 Pisa, Italy
| | - Natalia Sanchez de Groot
- Unitat
de Bioquímica, Departament de Bioquímica i Biologia
Molecular, Universitat Autònoma de
Barcelona, 08193 Barcelona, Spain
| | - Gian Gaetano Tartaglia
- RNA
Systems Biology Lab, Center for Human Technologies, Istituto Italiano di Tecnologia, Via Enrico Melen, 83, 16152 Genova, Italy
- Catalan
Institution for Research and Advanced Studies, ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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8
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Jung J, Tan C, Sugita Y. GENESIS CGDYN: large-scale coarse-grained MD simulation with dynamic load balancing for heterogeneous biomolecular systems. Nat Commun 2024; 15:3370. [PMID: 38643169 PMCID: PMC11032353 DOI: 10.1038/s41467-024-47654-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/08/2024] [Indexed: 04/22/2024] Open
Abstract
Residue-level coarse-grained (CG) molecular dynamics (MD) simulation is widely used to investigate slow biological processes that involve multiple proteins, nucleic acids, and their complexes. Biomolecules in a large simulation system are distributed non-uniformly, limiting computational efficiency with conventional methods. Here, we develop a hierarchical domain decomposition scheme with dynamic load balancing for heterogeneous biomolecular systems to keep computational efficiency even after drastic changes in particle distribution. These schemes are applied to the dynamics of intrinsically disordered protein (IDP) droplets. During the fusion of two droplets, we find that the changes in droplet shape correlate with the mixing of IDP chains. Additionally, we simulate large systems with multiple IDP droplets, achieving simulation sizes comparable to those observed in microscopy. In our MD simulations, we directly observe Ostwald ripening, a phenomenon where small droplets dissolve and their molecules redeposit into larger droplets. These methods have been implemented in CGDYN of the GENESIS software, offering a tool for investigating mesoscopic biological processes using the residue-level CG models.
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Affiliation(s)
- Jaewoon Jung
- Computational Biophysics Research Team, RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan
| | - Cheng Tan
- Computational Biophysics Research Team, RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan
| | - Yuji Sugita
- Computational Biophysics Research Team, RIKEN Center for Computational Science, Kobe, Hyogo, 650-0047, Japan.
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama, 351-0198, Japan.
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, 650-0047, Japan.
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9
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Yucel-Polat A, Campos-Melo D, Alikhah A, Strong MJ. Dynamic Localization of Paraspeckle Components under Osmotic Stress. Noncoding RNA 2024; 10:23. [PMID: 38668381 PMCID: PMC11053584 DOI: 10.3390/ncrna10020023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/05/2024] [Accepted: 04/10/2024] [Indexed: 04/29/2024] Open
Abstract
Paraspeckles are nuclear condensates formed by NEAT1_2 lncRNA and different RNA-binding proteins. In general, these membraneless organelles function in the regulation of gene expression and translation and in miRNA processing, and in doing this, they regulate cellular homeostasis and mediate pro-survival in the cell. Despite evidence showing the importance of paraspeckles in the stress response, the dynamics of paraspeckles and their components under conditions of osmotic stress remain unknown. We exposed HEK293T cells to sorbitol and examined NEAT1_2 expression using real-time PCR. Localization and quantification of the main paraspeckle components, NEAT1_2, PSPC1, NONO, and SFPQ, in different cellular compartments was performed using smFISH and immunofluorescence. Our findings showed a significant decrease in total NEAT1_2 expression in cells after osmotic stress. Sorbitol shifted the subcellular localization of NEAT1_2, PSPC1, NONO, and SFPQ from the nucleus to the cytoplasm and decreased the number and size of NEAT1_2 foci in the nucleus. PSPC1 formed immunoreactive cytoplasmic fibrils under conditions of osmotic stress, which slowly disassembled under recovery. Our study deepens the paraspeckle dynamics in response to stress, suggesting a novel role for NEAT1_2 in the cytoplasm in osmotic stress and physiological conditions.
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Affiliation(s)
- Aysegul Yucel-Polat
- Molecular Medicine Group, Schulich School of Medicine & Dentistry, Robarts Research Institute, Western University, London, ON N6A 3K7, Canada; (A.Y.-P.); (A.A.)
| | - Danae Campos-Melo
- Molecular Medicine Group, Schulich School of Medicine & Dentistry, Robarts Research Institute, Western University, London, ON N6A 3K7, Canada; (A.Y.-P.); (A.A.)
| | - Asieh Alikhah
- Molecular Medicine Group, Schulich School of Medicine & Dentistry, Robarts Research Institute, Western University, London, ON N6A 3K7, Canada; (A.Y.-P.); (A.A.)
| | - Michael J. Strong
- Molecular Medicine Group, Schulich School of Medicine & Dentistry, Robarts Research Institute, Western University, London, ON N6A 3K7, Canada; (A.Y.-P.); (A.A.)
- Department of Clinical Neurological Sciences, Schulich School of Medicine & Dentistry, Western University, London, ON N6A 3K7, Canada
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10
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Beck M, Covino R, Hänelt I, Müller-McNicoll M. Understanding the cell: Future views of structural biology. Cell 2024; 187:545-562. [PMID: 38306981 DOI: 10.1016/j.cell.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 02/04/2024]
Abstract
Determining the structure and mechanisms of all individual functional modules of cells at high molecular detail has often been seen as equal to understanding how cells work. Recent technical advances have led to a flush of high-resolution structures of various macromolecular machines, but despite this wealth of detailed information, our understanding of cellular function remains incomplete. Here, we discuss present-day limitations of structural biology and highlight novel technologies that may enable us to analyze molecular functions directly inside cells. We predict that the progression toward structural cell biology will involve a shift toward conceptualizing a 4D virtual reality of cells using digital twins. These will capture cellular segments in a highly enriched molecular detail, include dynamic changes, and facilitate simulations of molecular processes, leading to novel and experimentally testable predictions. Transferring biological questions into algorithms that learn from the existing wealth of data and explore novel solutions may ultimately unveil how cells work.
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Affiliation(s)
- Martin Beck
- Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany; Goethe University Frankfurt, Frankfurt, Germany.
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
| | - Inga Hänelt
- Goethe University Frankfurt, Frankfurt, Germany.
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11
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Takeiwa T, Ikeda K, Horie K, Inoue S. Role of RNA binding proteins of the Drosophila behavior and human splicing (DBHS) family in health and cancer. RNA Biol 2024; 21:1-17. [PMID: 38551131 PMCID: PMC10984136 DOI: 10.1080/15476286.2024.2332855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2024] [Indexed: 04/02/2024] Open
Abstract
RNA-binding proteins (RBPs) play crucial roles in the functions and homoeostasis of various tissues by regulating multiple events of RNA processing including RNA splicing, intracellular RNA transport, and mRNA translation. The Drosophila behavior and human splicing (DBHS) family proteins including PSF/SFPQ, NONO, and PSPC1 are ubiquitously expressed RBPs that contribute to the physiology of several tissues. In mammals, DBHS proteins have been reported to contribute to neurological diseases and play crucial roles in cancers, such as prostate, breast, and liver cancers, by regulating cancer-specific gene expression. Notably, in recent years, multiple small molecules targeting DBHS family proteins have been developed for application as cancer therapeutics. This review provides a recent overview of the functions of DBHS family in physiology and pathophysiology, and discusses the application of DBHS family proteins as promising diagnostic and therapeutic targets for cancers.
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Affiliation(s)
- Toshihiko Takeiwa
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Itabashi-ku, Tokyo, Japan
| | - Kazuhiro Ikeda
- Division of Systems Medicine & Gene Therapy, Faculty of Medicine, Saitama Medical University, Hidaka, Saitama, Japan
| | - Kuniko Horie
- Division of Systems Medicine & Gene Therapy, Faculty of Medicine, Saitama Medical University, Hidaka, Saitama, Japan
| | - Satoshi Inoue
- Department of Systems Aging Science and Medicine, Tokyo Metropolitan Institute for Geriatrics and Gerontology, Itabashi-ku, Tokyo, Japan
- Division of Systems Medicine & Gene Therapy, Faculty of Medicine, Saitama Medical University, Hidaka, Saitama, Japan
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12
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Marshall AC, Cummins J, Kobelke S, Zhu T, Widagdo J, Anggono V, Hyman A, Fox AH, Bond CS, Lee M. Different Low-complexity Regions of SFPQ Play Distinct Roles in the Formation of Biomolecular Condensates. J Mol Biol 2023; 435:168364. [PMID: 37952770 DOI: 10.1016/j.jmb.2023.168364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/14/2023]
Abstract
Demixing of proteins and nucleic acids into condensed liquid phases is rapidly emerging as a ubiquitous mechanism underlying the complex spatiotemporal organisation of molecules within the cell. Long disordered regions of low sequence complexity (LCRs) are a common feature of proteins that form liquid-like microscopic biomolecular condensates. In particular, RNA-binding proteins with prion-like regions have emerged as key drivers of liquid demixing to form condensates such as nucleoli, paraspeckles and stress granules. Splicing factor proline- and glutamine-rich (SFPQ) is an RNA- and DNA-binding protein essential for DNA repair and paraspeckle formation. SFPQ contains two LCRs of different length and composition. Here, we show that the shorter C-terminal LCR of SFPQ is the main region responsible for the condensation of SFPQ in vitro and in the cell nucleus. In contrast, we find that the longer N-terminal prion-like LCR of SFPQ attenuates condensation of the full-length protein, suggesting a more regulatory role in preventing aberrant condensate formation in the cell. The compositions of these respective LCRs are discussed with reference to current literature. Our data add nuance to the emerging understanding of biomolecular condensation, by providing the first example of a common multifunctional nucleic acid-binding protein with an extensive prion-like region that serves to regulate rather than drive condensate formation.
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Affiliation(s)
- Andrew C Marshall
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Jerry Cummins
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Simon Kobelke
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia
| | - Tianyi Zhu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jocelyn Widagdo
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Victor Anggono
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Anthony Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Archa H Fox
- School of Human Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Charles S Bond
- School of Molecular Sciences, The University of Western Australia, Crawley, WA 6009, Australia.
| | - Mihwa Lee
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia.
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13
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Obuse C, Hirose T. Functional domains of nuclear long noncoding RNAs: Insights into gene regulation and intracellular architecture. Curr Opin Cell Biol 2023; 85:102250. [PMID: 37806294 DOI: 10.1016/j.ceb.2023.102250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/12/2023] [Accepted: 09/07/2023] [Indexed: 10/10/2023]
Abstract
Recent functional research on long noncoding RNAs (lncRNAs) has revealed their significant regulatory roles in gene expression and intracellular architecture. Well-characterized examples of such lncRNAs include Xist and NEAT1_2, which play critical roles in heterochromatin formation of inactive X-chromosomes and paraspeckle assembly, in mammalian cells. Both lncRNAs possess modular domain structures with multiple functionally distinct domains that serve as platforms for specific RNA-binding proteins (RBPs), which dictate the function of each lncRNA. Some of these RBPs bind characteristic RNA structures, which can be targeted by small chemical compounds that modulate lncRNA function by perturbing the interaction of RBPs with the RNA structures. Therefore, RNA structures hidden in lncRNAs represent a novel and potent type of therapeutic target.
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Affiliation(s)
- Chikashi Obuse
- Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan; Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita 565-0871, Japan
| | - Tetsuro Hirose
- Graduate School of Science, Osaka University, Toyonaka 560-0043, Japan; Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan; Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita 565-0871, Japan.
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14
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Yamamoto T, Yamazaki T, Ninomiya K, Hirose T. Nascent ribosomal RNA act as surfactant that suppresses growth of fibrillar centers in nucleolus. Commun Biol 2023; 6:1129. [PMID: 37935838 PMCID: PMC10630424 DOI: 10.1038/s42003-023-05519-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 10/27/2023] [Indexed: 11/09/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) has been thought to be the biophysical principle governing the assembly of the multiphase structures of nucleoli, the site of ribosomal biogenesis. Condensates assembled through LLPS increase their sizes to minimize the surface energy as far as their components are available. However, multiple microphases, fibrillar centers (FCs), dispersed in a nucleolus are stable and their sizes do not grow unless the transcription of pre-ribosomal RNA (pre-rRNA) is inhibited. To understand the mechanism of the suppression of the FC growth, we here construct a minimal theoretical model by taking into account nascent pre-rRNAs tethered to FC surfaces by RNA polymerase I. The prediction of this theory was supported by our experiments that quantitatively measure the dependence of the size of FCs on the transcription level. This work sheds light on the role of nascent RNAs in controlling the size of nuclear bodies.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo, 001-0021, Japan.
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8, Honcho, Kawaguchi, Saitama, 332-0012, Japan.
| | - Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.
| | - Kensuke Ninomiya
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
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15
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Takakuwa H, Yamazaki T, Souquere S, Adachi S, Yoshino H, Fujiwara N, Yamamoto T, Natsume T, Nakagawa S, Pierron G, Hirose T. Shell protein composition specified by the lncRNA NEAT1 domains dictates the formation of paraspeckles as distinct membraneless organelles. Nat Cell Biol 2023; 25:1664-1675. [PMID: 37932453 DOI: 10.1038/s41556-023-01254-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 09/12/2023] [Indexed: 11/08/2023]
Abstract
Many membraneless organelles (MLOs) formed through phase separation play crucial roles in various cellular processes. Although these MLOs co-exist in cells, how they maintain their independence without coalescence or engulfment remains largely unknown. Here, we investigated the molecular mechanism by which paraspeckles with core-shell architecture scaffolded by NEAT1_2 long noncoding RNAs exist as distinct MLOs. We identified NEAT1 deletion mutants that assemble paraspeckles that are incorporated into nuclear speckles. Several paraspeckle proteins, including SFPQ, HNRNPF and BRG1, prevent this incorporation and thus contribute to the segregation of paraspeckles from nuclear speckles. Shell localization of these proteins in the paraspeckles, which is determined by NEAT1_2 long noncoding RNA domains, is required for this segregation process. Conversely, U2-related spliceosomal proteins are involved in internalizing the paraspeckles into nuclear speckles. This study shows that the paraspeckle shell composition dictates the independence of MLOs in the nucleus, providing insights into the importance of the shell in defining features and functions of MLOs.
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Affiliation(s)
- Hiro Takakuwa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
| | | | - Shungo Adachi
- Department of Proteomics, National Cancer Center Research Institute, Tokyo, Japan
| | - Hyura Yoshino
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Naoko Fujiwara
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan
| | - Tohru Natsume
- Cellular and Molecular Biotechnology Research Institute, National Institute for Advanced Industrial Science and Technology, Tokyo, Japan
| | - Shinichi Nakagawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Gerard Pierron
- Centre National de la Recherche Scientifique, UMR-9196, Gustave Roussy, Villejuif, France
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan.
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16
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Schmit JD, Dundr M. Keeping membraneless organelles apart. Nat Cell Biol 2023; 25:1566-1567. [PMID: 37932454 DOI: 10.1038/s41556-023-01265-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Affiliation(s)
- Jeremy D Schmit
- Department of Physics, Kansas State University, Manhattan, KS, USA
| | - Miroslav Dundr
- Center for Cancer Cell Biology, Rosalind Franklin University of Medicine & Science, Chicago Medical School, North Chicago, IL, USA.
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17
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Yamamoto T, Kinoshita K, Hirano T. Elasticity control of entangled chromosomes: Crosstalk between condensin complexes and nucleosomes. Biophys J 2023; 122:3869-3881. [PMID: 37571823 PMCID: PMC10560673 DOI: 10.1016/j.bpj.2023.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/18/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023] Open
Abstract
Condensin-mediated loop extrusion is now considered as the main driving force of mitotic chromosome assembly. Recent experiments have shown, however, that a class of mutant condensin complexes deficient in loop extrusion can assemble chromosome-like structures in Xenopus egg extracts, although these structures are somewhat different from those assembled by wild-type condensin complexes. In the absence of topoisomerase II (topo II), the mutant condensin complexes produce an unusual round-shaped structure termed a bean, which consists of a DNA-dense central core surrounded by a DNA-sparse halo. The mutant condensin complexes accumulate in the core, whereas histones are more concentrated in the halo than in the core. We consider that this peculiar structure serves as a model system to study how DNA entanglements, nucleosomes, and condensin functionally crosstalk with each other. To gain insight into how the bean structure is formed, here we construct a theoretical model. Our theory predicts that the core is formed by attractive interactions between mutant condensin complexes, whereas the halo is stabilized by the energy reduction through the selective accumulation of nucleosomes. The formation of the halo increases the elastic free energy due to the DNA entanglement in the core, but the latter free energy is compensated by condensin complexes that suppress the assembly of nucleosomes.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery (ICReDD), Hokkaido University, Sapporo, Hokkaido, Japan.
| | | | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama, Japan
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18
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Arakawa K, Hirose T, Inada T, Ito T, Kai T, Oyama M, Tomari Y, Yoda T, Nakagawa S. Nondomain biopolymers: Flexible molecular strategies to acquire biological functions. Genes Cells 2023; 28:539-552. [PMID: 37249032 DOI: 10.1111/gtc.13050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/31/2023]
Abstract
A long-standing assumption in molecular biology posits that the conservation of protein and nucleic acid sequences emphasizes the functional significance of biomolecules. These conserved sequences fold into distinct secondary and tertiary structures, enable highly specific molecular interactions, and regulate complex yet organized molecular processes within living cells. However, recent evidence suggests that biomolecules can also function through primary sequence regions that lack conservation across species or gene families. These regions typically do not form rigid structures, and their inherent flexibility is critical for their functional roles. This review examines the emerging roles and molecular mechanisms of "nondomain biomolecules," whose functions are not easily predicted due to the absence of conserved functional domains. We propose the hypothesis that both domain- and nondomain-type molecules work together to enable flexible and efficient molecular processes within the highly crowded intracellular environment.
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Grants
- 21H05273 Ministry of Education, Culture, Sports, Science and Technology
- 21H05274 Ministry of Education, Culture, Sports, Science and Technology
- 21H05275 Ministry of Education, Culture, Sports, Science and Technology
- 21H05276 Ministry of Education, Culture, Sports, Science and Technology
- 21H05277 Ministry of Education, Culture, Sports, Science and Technology
- 21H05278 Ministry of Education, Culture, Sports, Science and Technology
- 21H05279 Ministry of Education, Culture, Sports, Science and Technology
- 21H05280 Ministry of Education, Culture, Sports, Science and Technology
- 21H05281 Ministry of Education, Culture, Sports, Science and Technology
- 21H05282 Ministry of Education, Culture, Sports, Science and Technology
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Affiliation(s)
- Kazuharu Arakawa
- Institute for Advanced Biosciences, Keio University, Tokyo, Japan
| | - Tetsuro Hirose
- RNA Biofunction Laboratory, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Toshifumi Inada
- Division of RNA and Gene Regulation, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takuhiro Ito
- Laboratory for Translation Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | - Toshie Kai
- Germline Biology Laboratory, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Masaaki Oyama
- Medical Proteomics Laboratory, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yukihide Tomari
- Laboratory of RNA Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Takao Yoda
- Nagahama Institute of Bio-Science and Technology, Nagahama, Japan
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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19
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Yamamoto T, Li W. Polymer brush inspired by ribosomal RNA transcription. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:61. [PMID: 37493801 DOI: 10.1140/epje/s10189-023-00323-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 07/12/2023] [Indexed: 07/27/2023]
Abstract
Pre-ribosomal RNAs are synthesized during the transcription by RNA polymerase I molecules localized at the surfaces of a nucleolus subcompartment. Inspired by the ribosomal RNA transcription, we here develop a scaling theory of a brush of polymers, where monomers are added to their grafted ends in the steady state. Our theory predicts that monomers newly added to the polymers stay at the vicinity of the surface due to the slow dynamics of the polymers and thus the polymer volume fraction increases with increasing the polymerization rate. The excluded volume interaction between polymers and reactant monomers suppresses the diffusion of reactant monomers and thus decreases the polymerization rate. The extent of the suppression of monomer diffusion increases with increasing the polymerization rate because the diffusion length decreases, rather than the condensation of polymers due to their slow dynamics.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, 001-0021, Hokkaido, Japan.
| | - Wei Li
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Kita 21 Nishi 10, Kita-ku, Sapporo, 001-0021, Hokkaido, Japan
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20
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Abstract
Multivalent proteins and nucleic acids, collectively referred to as multivalent associative biomacromolecules, provide the driving forces for the formation and compositional regulation of biomolecular condensates. Here, we review the key concepts of phase transitions of aqueous solutions of associative biomacromolecules, specifically proteins that include folded domains and intrinsically disordered regions. The phase transitions of these systems come under the rubric of coupled associative and segregative transitions. The concepts underlying these processes are presented, and their relevance to biomolecular condensates is discussed.
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Affiliation(s)
- Rohit V Pappu
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Samuel R Cohen
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
- Center of Regenerative Medicine, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Furqan Dar
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mina Farag
- Department of Biomedical Engineering, Center for Biomolecular Condensates (CBC), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Mrityunjoy Kar
- Max Planck Institute of Cell Biology and Genetics, 01307 Dresden, Germany
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21
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Chauhan G, Bremer A, Dar F, Mittag T, Pappu RV. Crowder titrations enable the quantification of driving forces for macromolecular phase separation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.03.547544. [PMID: 37461587 PMCID: PMC10350001 DOI: 10.1101/2023.07.03.547544] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Macromolecular solubility is an important contributor to the driving forces for phase separation. Formally, the driving forces in a binary mixture comprising a macromolecule dissolved in a solvent can be quantified in terms of the saturation concentration, which is the threshold macromolecular concentration above which the mixture separates into coexisting dense and dilute phases. Additionally, the second virial coefficient, which measures the effective strength of solvent-mediated intermolecular interactions provides direct assessments of solvent quality. The sign and magnitude of second virial coefficients will be governed by a combination of solution conditions and the nature of the macromolecule of interest. Here, we show, using a combination of theory, simulation, and in vitro experiments, that titrations of crowders, providing they are true depletants, can be used to extract the intrinsic driving forces for macromolecular phase separation. This refers to saturation concentrations in the absence of crowders and the second virial coefficients that quantify the magnitude of the incompatibility between macromolecules and the solvent. Our results show how the depletion-mediated attractions afforded by crowders can be leveraged to obtain comparative assessments of macromolecule-specific, intrinsic driving forces for phase separation. SIGNIFICANCE Phase separation has emerged as a process of significant relevance to sorting macromolecules into distinct compartments, thereby enabling spatial and temporal control over cellular matter. Considerable effort is being invested into uncovering the driving forces that enable the separation of macromolecular solutions into coexisting phases. At its heart, this process is governed by the balance of macromolecule-solvent, inter-macromolecule, and solvent-solvent interactions. We show that the driving forces for phase separation, including the coefficients that measure interaction strengths between macromolecules, can be extracted by titrating the concentrations of crowders that enable macromolecules to phase separate at lower concentrations. Our work paves the way to leverage specific categories of measurements for quantitative characterizations of driving forces for phase separation.
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22
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Fierro C, Gatti V, La Banca V, De Domenico S, Scalera S, Corleone G, Fanciulli M, De Nicola F, Mauriello A, Montanaro M, Calin GA, Melino G, Peschiaroli A. The long non-coding RNA NEAT1 is a ΔNp63 target gene modulating epidermal differentiation. Nat Commun 2023; 14:3795. [PMID: 37365156 DOI: 10.1038/s41467-023-39011-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
The transcription factor ΔNp63 regulates epithelial stem cell function and maintains the integrity of stratified epithelial tissues by acting as transcriptional repressor or activator towards a distinct subset of protein-coding genes and microRNAs. However, our knowledge of the functional link between ∆Np63 transcriptional activity and long non-coding RNAs (lncRNAs) expression is quite limited. Here, we show that in proliferating human keratinocytes ∆Np63 represses the expression of the lncRNA NEAT1 by recruiting the histone deacetylase HDAC1 to the proximal promoter of NEAT1 genomic locus. Upon induction of differentiation, ∆Np63 down-regulation is associated by a marked increase of NEAT1 RNA levels, resulting in an increased assembly of paraspeckles foci both in vitro and in human skin tissues. RNA-seq analysis associated with global DNA binding profile (ChIRP-seq) revealed that NEAT1 associates with the promoter of key epithelial transcription factors sustaining their expression during epidermal differentiation. These molecular events might explain the inability of NEAT1-depleted keratinocytes to undergo the proper formation of epidermal layers. Collectively, these data uncover the lncRNA NEAT1 as an additional player of the intricate network orchestrating epidermal morphogenesis.
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Affiliation(s)
- Claudia Fierro
- Department of Experimental Medicine, Tor Vergata Oncoscience Research (TOR), University of Rome "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy
- Translational Pediatrics and Clinical Genetics Research Division, Bambino Gesù Children's Hospital, IRCSS, Piazza Sant'Onofrio, 4, Rome, Italy
| | - Veronica Gatti
- Institute of Translational Pharmacology (IFT), CNR, Via Fosso del Cavaliere 100, 00133, Rome, Italy
| | - Veronica La Banca
- Department of Experimental Medicine, Tor Vergata Oncoscience Research (TOR), University of Rome "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy
| | - Sara De Domenico
- Department of Experimental Medicine, Tor Vergata Oncoscience Research (TOR), University of Rome "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy
| | - Stefano Scalera
- UOSD SAFU, Department of Research, Advanced Diagnostics, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Giacomo Corleone
- UOSD SAFU, Department of Research, Advanced Diagnostics, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Maurizio Fanciulli
- UOSD SAFU, Department of Research, Advanced Diagnostics, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Francesca De Nicola
- UOSD SAFU, Department of Research, Advanced Diagnostics, and Technological Innovation, Translational Research Area, IRCCS Regina Elena National Cancer Institute, Rome, Italy
| | - Alessandro Mauriello
- Department of Experimental Medicine, Tor Vergata Oncoscience Research (TOR), University of Rome "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy
| | - Manuela Montanaro
- Department of Experimental Medicine, Tor Vergata Oncoscience Research (TOR), University of Rome "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy
| | - George A Calin
- Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
- Center for RNA Interference and Non-Coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Gerry Melino
- Department of Experimental Medicine, Tor Vergata Oncoscience Research (TOR), University of Rome "Tor Vergata", Via Montpellier 1, 00133, Rome, Italy
| | - Angelo Peschiaroli
- Institute of Translational Pharmacology (IFT), CNR, Via Fosso del Cavaliere 100, 00133, Rome, Italy.
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23
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Srinivas T, Mathias C, Oliveira-Mateos C, Guil S. Roles of lncRNAs in brain development and pathogenesis: Emerging therapeutic opportunities. Mol Ther 2023; 31:1550-1561. [PMID: 36793211 PMCID: PMC10277896 DOI: 10.1016/j.ymthe.2023.02.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/02/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
The human genome is pervasively transcribed, producing a majority of short and long noncoding RNAs (lncRNAs) that can influence cellular programs through a variety of transcriptional and post-transcriptional regulatory mechanisms. The brain houses the richest repertoire of long noncoding transcripts, which function at every stage during central nervous system development and homeostasis. An example of functionally relevant lncRNAs is species involved in spatiotemporal organization of gene expression in different brain regions, which play roles at the nuclear level and in transport, translation, and decay of other transcripts in specific neuronal sites. Research in the field has enabled identification of the contributions of specific lncRNAs to certain brain diseases, including Alzheimer's disease, Parkinson's disease, cancer, and neurodevelopmental disorders, resulting in notions of potential therapeutic strategies that target these RNAs to recover the normal phenotype. Here, we summarize the latest mechanistic findings associated with lncRNAs in the brain, focusing on their dysregulation in neurodevelopmental or neurodegenerative disorders, their use as biomarkers for central nervous system (CNS) diseases in vitro and in vivo, and their potential utility for therapeutic strategies.
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Affiliation(s)
- Tara Srinivas
- Josep Carreras Leukaemia Research Institute (IJC), Badalona, 08916 Barcelona, Catalonia, Spain
| | - Carolina Mathias
- Department of Genetics, Federal University of Parana, Post-graduation Program in Genetics, Curitiba, PR, Brazil; Laboratory of Applied Science and Technology in Health, Carlos Chagas Institute, Oswaldo Cruz Foundation (Fiocruz), Curitiba, PR, Brazil
| | | | - Sonia Guil
- Josep Carreras Leukaemia Research Institute (IJC), Badalona, 08916 Barcelona, Catalonia, Spain; Germans Trias i Pujol Health Science Research Institute, Badalona, 08916 Barcelona, Catalonia, Spain.
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24
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Wakao S, Saitoh N, Awazu A. Mathematical model of structural changes in nuclear speckle. Biophys Physicobiol 2023; 20:e200020. [PMID: 38496241 PMCID: PMC10941963 DOI: 10.2142/biophysico.bppb-v20.0020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/26/2023] [Indexed: 03/19/2024] Open
Abstract
Nuclear speckles are nuclear bodies consisting of populations of small and irregularly shaped droplet-like molecular condensates that contain various splicing factors. Recent experiments have revealed the following structural features of nuclear speckles: (I) Each molecular condensate contains SON and SRRM2 proteins, and MALAT1 non-coding RNA surrounds these condensates; (II) During normal interphase of the cell cycle in multicellular organisms, these condensates are broadly distributed throughout the nucleus. In contrast, when cell transcription is suppressed, the condensates fuse and form strongly condensed spherical droplets; (III) SON is dispersed spatially in MALAT1 knocked-down cells and MALAT1 is dispersed in SON knocked-down cells because of the collapse of the nuclear speckles. However, the detailed interactions among the molecules that are mechanistically responsible for the structural variation remain unknown. In this study, a coarse-grained molecular dynamics model of the nuclear speckle was developed by considering the dynamics of SON, SRRM2, MALAT1, and pre-mRNA as representative components of the condensates. The simulations reproduced the structural changes, which were used to predict the interaction network among the representative components of the condensates.
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Affiliation(s)
- Shingo Wakao
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Hiroshima 739-8526, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of Japanese Foundation for Cancer Research, Koto-ku, Tokyo 135-8550, Japan
| | - Akinori Awazu
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashihiroshima, Hiroshima 739-8526, Japan
- Research Center for the Mathematics on Chromatin Live Dynamics, Hiroshima University, Higashihiroshima, Hiroshima 739-8526, Japan
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25
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Hirose T, Ninomiya K, Nakagawa S, Yamazaki T. A guide to membraneless organelles and their various roles in gene regulation. Nat Rev Mol Cell Biol 2023; 24:288-304. [PMID: 36424481 DOI: 10.1038/s41580-022-00558-8] [Citation(s) in RCA: 106] [Impact Index Per Article: 106.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2022] [Indexed: 11/25/2022]
Abstract
Membraneless organelles (MLOs) are detected in cells as dots of mesoscopic size. By undergoing phase separation into a liquid-like or gel-like phase, MLOs contribute to intracellular compartmentalization of specific biological functions. In eukaryotes, dozens of MLOs have been identified, including the nucleolus, Cajal bodies, nuclear speckles, paraspeckles, promyelocytic leukaemia protein (PML) nuclear bodies, nuclear stress bodies, processing bodies (P bodies) and stress granules. MLOs contain specific proteins, of which many possess intrinsically disordered regions (IDRs), and nucleic acids, mainly RNA. Many MLOs contribute to gene regulation by different mechanisms. Through sequestration of specific factors, MLOs promote biochemical reactions by simultaneously concentrating substrates and enzymes, and/or suppressing the activity of the sequestered factors elsewhere in the cell. Other MLOs construct inter-chromosomal hubs by associating with multiple loci, thereby contributing to the biogenesis of macromolecular machineries essential for gene expression, such as ribosomes and spliceosomes. The organization of many MLOs includes layers, which might have different biophysical properties and functions. MLOs are functionally interconnected and are involved in various diseases, prompting the emergence of therapeutics targeting them. In this Review, we introduce MLOs that are relevant to gene regulation and discuss their assembly, internal structure, gene-regulatory roles in transcription, RNA processing and translation, particularly in stress conditions, and their disease relevance.
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Affiliation(s)
- Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan.
| | - Kensuke Ninomiya
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Shinichi Nakagawa
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | - Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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26
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Sagan SM, Weber SC. Let's phase it: viruses are master architects of biomolecular condensates. Trends Biochem Sci 2023; 48:229-243. [PMID: 36272892 DOI: 10.1016/j.tibs.2022.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 11/15/2022]
Abstract
Viruses compartmentalize their replication and assembly machinery to both evade detection and concentrate the viral proteins and nucleic acids necessary for genome replication and virion production. Accumulating evidence suggests that diverse RNA and DNA viruses form replication organelles and nucleocapsid assembly sites using phase separation. In general, the biogenesis of these compartments is regulated by two types of viral protein, collectively known as antiterminators and nucleocapsid proteins, respectively. Herein, we discuss how RNA viruses establish replication organelles and nucleocapsid assembly sites, and the evidence that these compartments form through phase separation. While this review focuses on RNA viruses, accumulating evidence suggests that all viruses rely on phase separation and form biomolecular condensates important for completing the infectious cycle.
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Affiliation(s)
- Selena M Sagan
- Department of Microbiology & Immunology, McGill University, Montreal, QC, Canada; Department of Biochemistry, McGill University, Montreal, QC, Canada.
| | - Stephanie C Weber
- Department of Biology, McGill University, Montreal, QC, Canada; Department of Physics, McGill University, Montreal, QC, Canada
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27
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Zhang S, Cooper JAL, Chong YS, Naveed A, Mayoh C, Jayatilleke N, Liu T, Amos S, Kobelke S, Marshall AC, Meers O, Choi YS, Bond CS, Fox AH. NONO enhances mRNA processing of super-enhancer-associated GATA2 and HAND2 genes in neuroblastoma. EMBO Rep 2023; 24:e54977. [PMID: 36416237 PMCID: PMC9900351 DOI: 10.15252/embr.202254977] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 11/02/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
High-risk neuroblastoma patients have poor survival rates and require better therapeutic options. High expression of a multifunctional DNA and RNA-binding protein, NONO, in neuroblastoma is associated with poor patient outcome; however, there is little understanding of the mechanism of NONO-dependent oncogenic gene regulatory activity in neuroblastoma. Here, we used cell imaging, biochemical and genome-wide molecular analysis to reveal complex NONO-dependent regulation of gene expression. NONO forms RNA- and DNA-tethered condensates throughout the nucleus and undergoes phase separation in vitro, modulated by nucleic acid binding. CLIP analyses show that NONO mainly binds to the 5' end of pre-mRNAs and modulates pre-mRNA processing, dependent on its RNA-binding activity. NONO regulates super-enhancer-associated genes, including HAND2 and GATA2. Abrogating NONO RNA binding, or phase separation activity, results in decreased expression of HAND2 and GATA2. Thus, future development of agents that target RNA-binding activity of NONO may have therapeutic potential in this cancer context.
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Affiliation(s)
- Song Zhang
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Jack AL Cooper
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Yee Seng Chong
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Alina Naveed
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Chelsea Mayoh
- Children's Cancer Institute AustraliaRandwickNSWAustralia
- Centre for Childhood Cancer ResearchUNSW SydneyKensingtonNSWAustralia
- School of Women's and Children's HealthUNSW SydneyKensingtonNSWAustralia
| | - Nisitha Jayatilleke
- Children's Cancer Institute AustraliaRandwickNSWAustralia
- Centre for Childhood Cancer ResearchUNSW SydneyKensingtonNSWAustralia
| | - Tao Liu
- Children's Cancer Institute AustraliaRandwickNSWAustralia
- Centre for Childhood Cancer ResearchUNSW SydneyKensingtonNSWAustralia
| | - Sebastian Amos
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Simon Kobelke
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Andrew C Marshall
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Oliver Meers
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Yu Suk Choi
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Charles S Bond
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Archa H Fox
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
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28
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Cao Y, Huang C, Zhao X, Yu J. Regulation of SUMOylation on RNA metabolism in cancers. Front Mol Biosci 2023; 10:1137215. [PMID: 36911524 PMCID: PMC9998694 DOI: 10.3389/fmolb.2023.1137215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 02/15/2023] [Indexed: 03/14/2023] Open
Abstract
Post-translational modifications of proteins play very important roles in regulating RNA metabolism and affect many biological pathways. Here we mainly summarize the crucial functions of small ubiquitin-like modifier (SUMO) modification in RNA metabolism including transcription, splicing, tailing, stability and modification, as well as its impact on the biogenesis and function of microRNA (miRNA) in particular. This review also highlights the current knowledge about SUMOylation regulation in RNA metabolism involved in many cellular processes such as cell proliferation and apoptosis, which is closely related to tumorigenesis and cancer progression.
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Affiliation(s)
- Yingting Cao
- Department of Biochemistry and Molecular Cell Biology and Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Caihu Huang
- Department of Biochemistry and Molecular Cell Biology and Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xian Zhao
- Department of Biochemistry and Molecular Cell Biology and Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianxiu Yu
- Department of Biochemistry and Molecular Cell Biology and Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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29
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Yamazaki T, Audas TE, Farny NG. Editorial: The why of RNA granules: Form, function, and regulation. Front Mol Biosci 2022; 9:1111463. [PMID: 36582206 PMCID: PMC9793083 DOI: 10.3389/fmolb.2022.1111463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Affiliation(s)
- Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan,*Correspondence: Tomohiro Yamazaki, ; Timothy E. Audas, ; Natalie G. Farny,
| | - Timothy E. Audas
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada,Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada,*Correspondence: Tomohiro Yamazaki, ; Timothy E. Audas, ; Natalie G. Farny,
| | - Natalie G. Farny
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States,*Correspondence: Tomohiro Yamazaki, ; Timothy E. Audas, ; Natalie G. Farny,
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30
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Mitrea DM, Mittasch M, Gomes BF, Klein IA, Murcko MA. Modulating biomolecular condensates: a novel approach to drug discovery. Nat Rev Drug Discov 2022; 21:841-862. [PMID: 35974095 PMCID: PMC9380678 DOI: 10.1038/s41573-022-00505-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2022] [Indexed: 12/12/2022]
Abstract
In the past decade, membraneless assemblies known as biomolecular condensates have been reported to play key roles in many cellular functions by compartmentalizing specific proteins and nucleic acids in subcellular environments with distinct properties. Furthermore, growing evidence supports the view that biomolecular condensates often form by phase separation, in which a single-phase system demixes into a two-phase system consisting of a condensed phase and a dilute phase of particular biomolecules. Emerging understanding of condensate function in normal and aberrant cellular states, and of the mechanisms of condensate formation, is providing new insights into human disease and revealing novel therapeutic opportunities. In this Perspective, we propose that such insights could enable a previously unexplored drug discovery approach based on identifying condensate-modifying therapeutics (c-mods), and we discuss the strategies, techniques and challenges involved.
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31
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Sekar D, Tusubira D, Ross K. TDP-43 and NEAT long non-coding RNA: Roles in neurodegenerative disease. Front Cell Neurosci 2022; 16:954912. [PMID: 36385948 PMCID: PMC9650703 DOI: 10.3389/fncel.2022.954912] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 10/11/2022] [Indexed: 01/03/2023] Open
Abstract
Understanding and ameliorating neurodegenerative diseases represents a key challenge for supporting the health span of the aging population. Diverse protein aggregates have been implicated in such neurodegenerative disorders, including amyloid-β, α-synuclein, tau, fused in sarcoma (FUS), and transactivation response element (TAR) DNA-binding protein 43 (TDP-43). Recent years have seen significant growth in our mechanistic knowledge of relationships between these proteins and some of the membrane-less nuclear structures that fulfill key roles in the cell function. These include the nucleolus, nuclear speckles, and paraspeckles. The ability of macromolecular protein:RNA complexes to partition these nuclear condensates through biophysical processes that involve liquid-liquid phase separation (LLPS) has also gained attention recently. The paraspeckle, which is scaffolded by the architectural long-non-coding RNA nuclear enriched abundant transcript 1 (NEAT1) plays central roles in RNA processing and metabolism and has been linked dynamically to TDP-43. In this mini-review, we outline essential early and recent insights in relation to TDP-43 proteinopathies. We then appraise the relationships between TDP-43 and NEAT1 in the context of neuronal paraspeckles and neuronal stress. We highlight key areas for investigation based on recent advances in our understanding of how TDP-43 affects neuronal function, especially in relation to messenger ribosomal nucleic acid (mRNA) splicing. Finally, we offer perspectives that should be considered for translational pipelines in order to improve health outcomes for the management of neurodegenerative diseases.
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Affiliation(s)
- Durairaj Sekar
- Centre for Cellular and Molecular Research, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, India
| | - Deusdedit Tusubira
- Department of Biochemistry, Mbarara University of Science and Technology, Mbarara, Uganda,*Correspondence: Deusdedit Tusubira, ; orcid.org/0000-0002-4698-424X
| | - Kehinde Ross
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom,Institute for Health Research, Liverpool John Moores University, Liverpool, United Kingdom,Kehinde Ross, ; orcid.org/0000-0003-0252-1152
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32
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Fefilova AS, Antifeeva IA, Gavrilova AA, Turoverov KK, Kuznetsova IM, Fonin AV. Reorganization of Cell Compartmentalization Induced by Stress. Biomolecules 2022; 12:1441. [PMID: 36291650 PMCID: PMC9599104 DOI: 10.3390/biom12101441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/30/2022] [Accepted: 10/01/2022] [Indexed: 11/17/2022] Open
Abstract
The discovery of intrinsically disordered proteins (IDPs) that do not have an ordered structure and nevertheless perform essential functions has opened a new era in the understanding of cellular compartmentalization. It threw the bridge from the mostly mechanistic model of the organization of the living matter to the idea of highly dynamic and functional "soft matter". This paradigm is based on the notion of the major role of liquid-liquid phase separation (LLPS) of biopolymers in the spatial-temporal organization of intracellular space. The LLPS leads to the formation of self-assembled membrane-less organelles (MLOs). MLOs are multicomponent and multifunctional biological condensates, highly dynamic in structure and composition, that allow them to fine-tune the regulation of various intracellular processes. IDPs play a central role in the assembly and functioning of MLOs. The LLPS importance for the regulation of chemical reactions inside the cell is clearly illustrated by the reorganization of the intracellular space during stress response. As a reaction to various types of stresses, stress-induced MLOs appear in the cell, enabling the preservation of the genetic and protein material during unfavourable conditions. In addition, stress causes structural, functional, and compositional changes in the MLOs permanently present inside the cells. In this review, we describe the assembly of stress-induced MLOs and the stress-induced modification of existing MLOs in eukaryotes, yeasts, and prokaryotes in response to various stress factors.
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Affiliation(s)
| | | | | | - Konstantin K. Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology of RAS, 194064 St. Petersburg, Russia
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33
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Yamazaki T, Yamamoto T, Hirose T. Micellization: A new principle in the formation of biomolecular condensates. Front Mol Biosci 2022; 9:974772. [PMID: 36106018 PMCID: PMC9465675 DOI: 10.3389/fmolb.2022.974772] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 07/20/2022] [Indexed: 11/18/2022] Open
Abstract
Phase separation is a fundamental mechanism for compartmentalization in cells and leads to the formation of biomolecular condensates, generally containing various RNA molecules. RNAs are biomolecules that can serve as suitable scaffolds for biomolecular condensates and determine their forms and functions. Many studies have focused on biomolecular condensates formed by liquid-liquid phase separation (LLPS), one type of intracellular phase separation mechanism. We recently identified that paraspeckle nuclear bodies use an intracellular phase separation mechanism called micellization of block copolymers in their formation. The paraspeckles are scaffolded by NEAT1_2 long non-coding RNAs (lncRNAs) and their partner RNA-binding proteins (NEAT1_2 RNA-protein complexes [RNPs]). The NEAT1_2 RNPs act as block copolymers and the paraspeckles assemble through micellization. In LLPS, condensates grow without bound as long as components are available and typically have spherical shapes to minimize surface tension. In contrast, the size, shape, and internal morphology of the condensates are more strictly controlled in micellization. Here, we discuss the potential importance and future perspectives of micellization of block copolymers of RNPs in cells, including the construction of designer condensates with optimal internal organization, shape, and size according to design guidelines of block copolymers.
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Affiliation(s)
- Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Japan
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34
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Yamamoto T, Yamazaki T, Hirose T. Triblock copolymer micelle model of spherical paraspeckles. Front Mol Biosci 2022; 9:925058. [PMID: 36072433 PMCID: PMC9441768 DOI: 10.3389/fmolb.2022.925058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Paraspeckles are nuclear bodies scaffolded by RNP complexes of NEAT1_2 RNA transcripts and multiple RNA-binding proteins. The assembly of paraspeckles is coupled with the transcription of NEAT1_2. Paraspeckles form the core-shell structure, where the two terminal regions of NEAT1_2 RNP complexes compose the shell of the paraspeckle and the middle regions of these complexes compose the core. We here construct a theoretical model of paraspeckles by taking into account the transcription of NEAT1_2 in an extension of the theory of block copolymer micelles. This theory predicts that the core-shell structure of a paraspeckle is assembled by the association of the middle region of NEAT1_2 RNP complexes due to the multivalent interactions between RBPs bound to these regions and by the relative affinity of the terminal regions of the complexes to the nucleoplasm. The latter affinity results in the effective repulsive interactions between terminal regions of the RNA complexes and limits the number of complexes composing the paraspeckle. In the wild type, the repulsive interaction between the middle and terminal block dominates the thermal fluctuation. However, the thermal fluctuation can be significant in a mutant, where a part of the terminal regions of NEAT1_2 is deleted, and distributes the shortened terminal regions randomly between the shell and the core, consistent with our recent experiments. With the upregulated transcription, the shortened terminal regions of NEAT1_2 in a deletion mutant is localized to the core to decrease the repulsive interaction between the terminal regions, while the structure does not change with the upregulation in the wild type. The robustness of the structure of paraspeckles in the wild type results from the polymeric nature of NEAT1_2 complexes.
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Affiliation(s)
- Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Japan
- *Correspondence: Tetsuya Yamamoto,
| | - Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Japan
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35
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Yamada A, Toya H, Tanahashi M, Kurihara M, Mito M, Iwasaki S, Kurosaka S, Takumi T, Fox A, Kawamura Y, Miura K, Nakagawa S. Species-specific formation of paraspeckles in intestinal epithelium revealed by characterization of NEAT1 in naked mole-rat. RNA (NEW YORK, N.Y.) 2022; 28:1128-1143. [PMID: 35654483 PMCID: PMC9297846 DOI: 10.1261/rna.079135.122] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Paraspeckles are mammalian-specific nuclear bodies built on the long noncoding RNA NEAT1_2 The molecular mechanisms of paraspeckle formation have been mainly studied using human or mouse cells, and it is not known if the same molecular components are involved in the formation of paraspeckles in other mammalian species. We thus investigated the expression pattern of NEAT1_2 in naked mole-rats (nNEAT1_2), which exhibit extreme longevity and lower susceptibility to cancer. In the intestine, nNEAT1_2 is widely expressed along the entire intestinal epithelium, which is different from the expression of mNeat1_2 that is restricted to the cells of the distal tip in mice. Notably, the expression of FUS, a FET family RNA binding protein, essential for the formation of paraspeckles both in humans and mice, was absent in the distal part of the intestinal epithelium in naked mole-rats. Instead, mRNAs of other FET family proteins EWSR1 and TAF15 were expressed in the distal region. Exogenous expression of these proteins in Fus-deficient murine embryonic fibroblast cells rescued the formation of paraspeckles. These observations suggest that nNEAT1_2 recruits a different set of RNA binding proteins in a cell type-specific manner during the formation of paraspeckles in different organisms.
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Affiliation(s)
- Akihiro Yamada
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Hikaru Toya
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Mayuko Tanahashi
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Misuzu Kurihara
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Mari Mito
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Saitama 351-0198, Japan
| | - Shintaro Iwasaki
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Saitama 351-0198, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561, Japan
| | | | - Toru Takumi
- RIKEN Brain Science Institute, Saitama 351-0198, Japan
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe 670-0017, Japan
| | - Archa Fox
- School of Human Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
- Harry Perkins Institute of Medical Research, Nedlands, Western Australia 6009, Australia
- School of Molecular Sciences, University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Yoshimi Kawamura
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
- Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Kumamoto 860-8556, Japan
| | - Kyoko Miura
- Department of Aging and Longevity Research, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
- Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Kumamoto 860-8556, Japan
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
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36
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Belmont AS. Nuclear Compartments: An Incomplete Primer to Nuclear Compartments, Bodies, and Genome Organization Relative to Nuclear Architecture. Cold Spring Harb Perspect Biol 2022; 14:a041268. [PMID: 34400557 PMCID: PMC9248822 DOI: 10.1101/cshperspect.a041268] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This work reviews nuclear compartments, defined broadly to include distinct nuclear structures, bodies, and chromosome domains. It first summarizes original cytological observations before comparing concepts of nuclear compartments emerging from microscopy versus genomic approaches and then introducing new multiplexed imaging approaches that promise in the future to meld both approaches. I discuss how previous models of radial distribution of chromosomes or the binary division of the genome into A and B compartments are now being refined by the recognition of more complex nuclear compartmentalization. The poorly understood question of how these nuclear compartments are established and maintained is then discussed, including through the modern perspective of phase separation, before moving on to address possible functions of nuclear compartments, using the possible role of nuclear speckles in modulating gene expression as an example. Finally, the review concludes with a discussion of future questions for this field.
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Affiliation(s)
- Andrew S Belmont
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, USA
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37
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Mittag T, Pappu RV. A conceptual framework for understanding phase separation and addressing open questions and challenges. Mol Cell 2022; 82:2201-2214. [PMID: 35675815 PMCID: PMC9233049 DOI: 10.1016/j.molcel.2022.05.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 05/04/2022] [Accepted: 05/13/2022] [Indexed: 12/11/2022]
Abstract
Macromolecular phase separation is being recognized for its potential importance and relevance as a driver of spatial organization within cells. Here, we describe a framework based on synergies between networking (percolation or gelation) and density (phase separation) transitions. Accordingly, the phase transitions in question are referred to as phase separation coupled to percolation (PSCP). The condensates that result from PSCP are viscoelastic network fluids. Such systems have sequence-, composition-, and topology-specific internal network structures that give rise to time-dependent interplays between viscous and elastic properties. Unlike pure phase separation, the process of PSCP gives rise to sequence-, chemistry-, and structure-specific distributions of clusters that can form at concentrations that lie well below the threshold concentration for phase separation. PSCP, influenced by specific versus solubility-determining interactions, also provides a bridge between different observations and helps answer questions and address challenges that have arisen regarding the role of macromolecular phase separation in biology.
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Affiliation(s)
- Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Science & Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, MO 63130, USA.
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38
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Udagawa O, Kato-Udagawa A, Hirano S. Promyelocytic leukemia nuclear body-like structures can assemble in mouse oocytes. Biol Open 2022; 11:275379. [PMID: 35579421 PMCID: PMC9194678 DOI: 10.1242/bio.059130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/06/2022] [Indexed: 11/29/2022] Open
Abstract
Promyelocytic leukemia (PML) nuclear bodies (PML-NBs), a class of membrane-less cellular organelles, participate in various biological activities. PML-NBs are known as the core-shell-type nuclear body, harboring ‘client’ proteins in their core. Although multiple membrane-less organelles work in the oocyte nucleus, PML-NBs have been predicted to be absent from oocytes. Here, we show that some well-known PML clients (but not endogenous PML) co-localized with small ubiquitin-related modifier (SUMO) protein in the nucleolus and peri-centromeric heterochromatin of maturing oocytes. In oocytes devoid of PML-NBs, endogenous PML protein localized in the vicinity of chromatin. During and after meiotic resumption, PML co-localized with SUMO gathering around chromosomes. To examine the benefit of the PML-NB-free intranuclear milieu in oocytes, we deliberately assembled PML-NBs by microinjecting human PML-encoding plasmids into oocytes. Under conditions of limited SUMO availability, assembled PML-NBs tended to cluster. Upon proteotoxic stress, SUMO delocalized from peri-centromeric heterochromatin and co-localized with SC35 (a marker of nuclear speckles)-positive large compartments, which was disturbed by pre-assembled PML-NBs. These observations suggest that the PML-NB-free intranuclear environment helps reserve SUMO for emergent responses by redirecting the flux of SUMO otherwise needed to maintain PML-NB dynamics. Summary: PML-NB-free intranuclear environment in the oocyte helps reserve SUMO for emergent responses by redirecting the flux of SUMO otherwise needed to maintain PML-NB dynamics.
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Affiliation(s)
- Osamu Udagawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
| | - Ayaka Kato-Udagawa
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
| | - Seishiro Hirano
- Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan
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39
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Feric M, Misteli T. Function moves biomolecular condensates in phase space. Bioessays 2022; 44:e2200001. [PMID: 35243657 PMCID: PMC9277701 DOI: 10.1002/bies.202200001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/19/2022] [Accepted: 02/22/2022] [Indexed: 11/08/2022]
Abstract
Phase separation underlies the formation of biomolecular condensates. We hypothesize the cellular processes that occur within condensates shape their structural features. We use the example of transcription to discuss structure-function relationships in condensates. Various types of transcriptional condensates have been reported across the evolutionary spectrum in the cell nucleus as well as in mitochondrial and bacterial nucleoids. In vitro and in vivo observations suggest that transcriptional activity of condensates influences their supramolecular structure, which in turn affects their function. Condensate organization thus becomes driven by differences in miscibility among the DNA and proteins of the transcription machinery and the RNA transcripts they generate. These considerations are in line with the notion that cellular processes shape the structural properties of condensates, leading to a dynamic, mutual interplay between structure and function in the cell.
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Affiliation(s)
- Marina Feric
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
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40
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Compartment-Specific Proximity Ligation Expands the Toolbox to Assess the Interactome of the Long Non-Coding RNA NEAT1. Int J Mol Sci 2022; 23:ijms23084432. [PMID: 35457249 PMCID: PMC9027746 DOI: 10.3390/ijms23084432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 04/06/2022] [Accepted: 04/13/2022] [Indexed: 12/23/2022] Open
Abstract
The nuclear paraspeckle assembly transcript 1 (NEAT1) locus encodes two long non-coding (lnc)RNA isoforms that are upregulated in many tumours and dynamically expressed in response to stress. NEAT1 transcripts form ribonucleoprotein complexes with numerous RNA-binding proteins (RBPs) to assemble paraspeckles and modulate the localisation and activity of gene regulatory enzymes as well as a subset of messenger (m)RNA transcripts. The investigation of the dynamic composition of NEAT1-associated proteins and mRNAs is critical to understand the function of NEAT1. Interestingly, a growing number of biochemical and genetic tools to assess NEAT1 interactomes has been reported. Here, we discuss the Hybridisation Proximity (HyPro) labeling technique in the context of NEAT1. HyPro labeling is a recently developed method to detect spatially ordered interactions of RNA-containing nuclear compartments in cultured human cells. After introducing NEAT1 and paraspeckles, we describe the advantages of the HyPro technology in the context of other methods to study RNA interactomes, and review the key findings in mapping NEAT1-associated RNA transcripts and protein binding partners. We further discuss the limitations and potential improvements of HyPro labeling, and conclude by delineating its applicability in paraspeckles-related cancer research.
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41
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Cochard A, Garcia-Jove Navarro M, Piroska L, Kashida S, Kress M, Weil D, Gueroui Z. RNA at the surface of phase-separated condensates impacts their size and number. Biophys J 2022; 121:1675-1690. [PMID: 35364105 PMCID: PMC9117936 DOI: 10.1016/j.bpj.2022.03.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 01/11/2022] [Accepted: 03/28/2022] [Indexed: 11/26/2022] Open
Abstract
While it is now recognized that specific RNAs and protein families are critical for the biogenesis of ribonucleoprotein (RNP) condensates, how these molecular constituents determine condensate size and morphology is unknown. To circumvent the biochemical complexity of endogenous RNP condensates, the use of programmable tools to reconstitute condensate formation with minimal constituents can be instrumental. Here we report a methodology to form RNA-containing condensates in living cells programmed to specifically recruit a single RNA species. Our bioengineered condensates are made of ArtiGranule scaffolds composed of an orthogonal protein that can bind to a specific heterologously expressed RNA. These scaffolds undergo liquid-liquid phase separation in cells and can be chemically controlled to prevent condensation or to trigger condensate dissolution. We found that the targeted RNAs localize at the condensate surface, either as isolated RNA molecules or as a homogenous corona of RNA molecules around the condensate. The recruitment of RNA changes the material properties of condensates by hardening the condensate body. Moreover, the condensate size scales with RNA surface density; the higher the RNA density, the smaller and more frequent the condensates. These results suggest a mechanism based on physical constraints, provided by RNAs at the condensate surface, that limit condensate growth and coalescence.
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Affiliation(s)
- Audrey Cochard
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France; Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire de Biologie du Développement, F-75005 Paris, France
| | - Marina Garcia-Jove Navarro
- PASTEUR, Department of Chemistry, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Leonard Piroska
- 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
| | - Michel Kress
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine (IBPS), Laboratoire de Biologie du Développement, F-75005 Paris, 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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42
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Ghosh S, Ataman M, Bak M, Börsch A, Schmidt A, Buczak K, Martin G, Dimitriades B, Herrmann CJ, Kanitz A, Zavolan M. CFIm-mediated alternative polyadenylation remodels cellular signaling and miRNA biogenesis. Nucleic Acids Res 2022; 50:3096-3114. [PMID: 35234914 PMCID: PMC8989530 DOI: 10.1093/nar/gkac114] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 01/31/2022] [Accepted: 02/04/2022] [Indexed: 12/13/2022] Open
Abstract
The mammalian cleavage factor I (CFIm) has been implicated in alternative polyadenylation (APA) in a broad range of contexts, from cancers to learning deficits and parasite infections. To determine how the CFIm expression levels are translated into these diverse phenotypes, we carried out a multi-omics analysis of cell lines in which the CFIm25 (NUDT21) or CFIm68 (CPSF6) subunits were either repressed by siRNA-mediated knockdown or over-expressed from stably integrated constructs. We established that >800 genes undergo coherent APA in response to changes in CFIm levels, and they cluster in distinct functional classes related to protein metabolism. The activity of the ERK pathway traces the CFIm concentration, and explains some of the fluctuations in cell growth and metabolism that are observed upon CFIm perturbations. Furthermore, multiple transcripts encoding proteins from the miRNA pathway are targets of CFIm-dependent APA. This leads to an increased biogenesis and repressive activity of miRNAs at the same time as some 3′ UTRs become shorter and presumably less sensitive to miRNA-mediated repression. Our study provides a first systematic assessment of a core set of APA targets that respond coherently to changes in CFIm protein subunit levels (CFIm25/CFIm68). We describe the elicited signaling pathways downstream of CFIm, which improve our understanding of the key role of CFIm in integrating RNA processing with other cellular activities.
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Affiliation(s)
- Souvik Ghosh
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Meric Ataman
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.,Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Maciej Bak
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.,Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Anastasiya Börsch
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.,Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Katarzyna Buczak
- Proteomics Core Facility, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Georges Martin
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Beatrice Dimitriades
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Christina J Herrmann
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.,Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Alexander Kanitz
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.,Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Mihaela Zavolan
- Computational and Systems Biology, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.,Swiss Institute of Bioinformatics, Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
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43
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Yamazaki T, Yamamoto T. Statistical Thermodynamics Approach for Intracellular Phase Separation. Methods Mol Biol 2022; 2509:361-393. [PMID: 35796975 DOI: 10.1007/978-1-0716-2380-0_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Phase separation is one of the fundamental processes to compartmentalize biomolecules in living cells. RNA-protein complexes (RNPs) often scaffold biomolecular condensates formed through phase separation. We here present a statistical thermodynamics approach to investigate intracellular phase separation. We first present the statistical thermodynamic theory of the liquid-liquid phase separation (LLPS) of two molecules (such as proteins and solvent molecules) and of a polymer solution (such as RNPs and solvent molecules). Condensates produced by LLPS show coarsening and/or coalescence to minimize their total surface area. In addition to the LLPS, there are other types of self-assembly, such as microphase separation, micellization, emulsification, and vesiculation, with which the growth of the assembly stops with optimal size and shape. We also describe a scaling theory of micelles of block copolymers, where their structures are analogous to the core-shell structure of paraspeckle nuclear bodies scaffolded by RNPs of NEAT1_2 long noncoding RNAs (lncRNAs) and RNA-binding proteins (RBPs). These theories treat the self-assembly of polymers in the thermodynamic equilibrium, where their concentrations and compositions do not change with time. In contrast, RNPs are produced according to the transcription of RNAs and are degraded with time. We therefore take into account the dynamical aspect of the production of RNPs in an extension of the theory of the self-assembly of soft matter. Finally, we discuss the structure of paraspeckles as an example to demonstrate that an approach combining experiment and theory is powerful to investigate the mechanism of intracellular phase separation.
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Affiliation(s)
- Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
| | - Tetsuya Yamamoto
- Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan
- PRESTO, Japan Science and Technology Agency (JST), Saitama, Japan
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44
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Rana U, Brangwynne CP, Panagiotopoulos AZ. Phase separation vs aggregation behavior for model disordered proteins. J Chem Phys 2021; 155:125101. [PMID: 34598580 DOI: 10.1063/5.0060046] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) is widely utilized by the cell to organize and regulate various biochemical processes. Although the LLPS of proteins is known to occur in a sequence-dependent manner, it is unclear how sequence properties dictate the nature of the phase transition and thereby influence condensed phase morphology. In this work, we have utilized grand canonical Monte Carlo simulations for a simple coarse-grained model of disordered proteins to systematically investigate how sequence distribution, sticker fraction, and chain length impact the formation of finite-size aggregates, which can preempt macroscopic phase separation for some sequences. We demonstrate that a normalized sequence charge decoration (SCD) parameter establishes a "soft" predictive criterion for distinguishing when a model protein undergoes macroscopic phase separation vs finite aggregation. Additionally, we find that this order parameter is strongly correlated with the critical density for phase separation, highlighting an unambiguous connection between sequence distribution and condensed phase density. Results obtained from an analysis of the order parameter reveal that at sufficiently long chain lengths, the vast majority of sequences are likely to phase separate. Our results suggest that classical LLPS should be the primary phase transition for disordered proteins when short-ranged attractive interactions dominate and suggest a possible reason behind recent findings of widespread phase separation throughout living cells.
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Affiliation(s)
- Ushnish Rana
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, USA
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45
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Affiliation(s)
- Tomohiro Yamazaki
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Tetsuro Hirose
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.
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46
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Yamazaki T, Yamamoto T, Yoshino H, Souquere S, Nakagawa S, Pierron G, Hirose T. Paraspeckles are constructed as block copolymer micelles. EMBO J 2021; 40:e107270. [PMID: 33885174 PMCID: PMC8204865 DOI: 10.15252/embj.2020107270] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/14/2021] [Accepted: 03/18/2021] [Indexed: 01/20/2023] Open
Abstract
Paraspeckles are constructed by NEAT1_2 architectural long noncoding RNAs. Their characteristic cylindrical shapes, with highly ordered internal organization, distinguish them from typical liquid-liquid phase-separated condensates. We experimentally and theoretically investigated how the shape and organization of paraspeckles are determined. We identified the NEAT1_2 RNA domains responsible for shell localization of the NEAT1_2 ends, which determine the characteristic internal organization. Using the soft matter physics, we then applied a theoretical framework to understand the principles that determine NEAT1_2 organization as well as shape, number, and size of paraspeckles. By treating paraspeckles as amphipathic block copolymer micelles, we could explain and predict the experimentally observed behaviors of paraspeckles upon NEAT1_2 domain deletions or transcriptional modulation. Thus, we propose that paraspeckles are block copolymer micelles assembled through a type of microphase separation, micellization. This work provides an experiment-based theoretical framework for the concept that ribonucleoprotein complexes (RNPs) can act as block copolymers to form RNA-scaffolding biomolecular condensates with optimal sizes and structures in cells.
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Affiliation(s)
| | - Tetsuya Yamamoto
- Institute for Chemical Reaction Design and DiscoveryHokkaido UniversitySapporoJapan
| | - Hyura Yoshino
- Institute for Genetic MedicineHokkaido UniversitySapporoJapan
| | | | | | - Gerard Pierron
- Centre National de la Recherche ScientifiqueUMR‐9196Gustave RoussyVillejuifFrance
| | - Tetsuro Hirose
- Graduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
- Institute for Genetic MedicineHokkaido UniversitySapporoJapan
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47
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ArcRNAs and the formation of nuclear bodies. Mamm Genome 2021; 33:382-401. [PMID: 34085114 DOI: 10.1007/s00335-021-09881-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/25/2021] [Indexed: 01/13/2023]
Abstract
Long noncoding RNAs (lncRNAs) have long been collectively and passively defined as transcripts that do not encode proteins. However, extensive functional studies performed over the last decade have enabled the classification of lncRNAs into multiple categories according to their functions and/or molecular properties. Architectual RNAs (arcRNAs) are a group of lncRNAs that serve as architectural components of submicron-scale cellular bodies or nonmembranous organelles, which are composed of specific sets of proteins and nucleic acids involved in particular molecular processes. In this review, we focus on arcRNAs that function in the nucleus, which provide a structural basis for the formation of nuclear bodies, nonmembranous organelles in the cell nucleus. We will summarize the current list of arcRNAs and proteins associated with classic and more recently discovered nuclear bodies and discuss general rules that govern the formation of nuclear bodies, emphasizing weak multivalent interactions mediated by innately flexible biomolecules.
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