1
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Makeyev EV, Huang S. The perinucleolar compartment: structure, function, and utility in anti-cancer drug development. Nucleus 2024; 15:2306777. [PMID: 38281066 PMCID: PMC10824145 DOI: 10.1080/19491034.2024.2306777] [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: 09/25/2023] [Accepted: 01/12/2024] [Indexed: 01/29/2024] Open
Abstract
The perinucleolar compartment (PNC) was initially identified as a nuclear structure enriched for the polypyrimidine tract-binding protein. Since then, the PNC has been implicated in carcinogenesis. The prevalence of this compartment is positively correlated with disease progression in various types of cancer, and its expression in primary tumors is linked to worse patient outcomes. Using the PNC as a surrogate marker for anti-cancer drug efficacy has led to the development of a clinical candidate for anti-metastasis therapies. The PNC is a multicomponent nuclear body situated at the periphery of the nucleolus. Thus far, several non-coding RNAs and RNA-binding proteins have been identified as the PNC components. Here, we summarize the current understanding of the structure and function of the PNC, as well as its recurrent links to cancer progression and metastasis.
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Affiliation(s)
- Eugene V. Makeyev
- Centre for Developmental Neurobiology, King’s College London, London, UK
| | - Sui Huang
- Department of Cell and Developmental Biology, Northwestern University, Chicago, IL, USA
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2
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Chen HF, Li ZP, Wu Q, Yu C, Yan JY, Bai YF, Zhu SM, Qian MX, Liu M, Xu LF, Peng Z, Zhang F. Inhibition of TAF1B impairs ribosome biosynthesis and suppresses cell proliferation in stomach adenocarcinoma through promoting c-MYC mRNA degradation. Heliyon 2024; 10:e23167. [PMID: 38169774 PMCID: PMC10758831 DOI: 10.1016/j.heliyon.2023.e23167] [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: 08/24/2023] [Revised: 11/23/2023] [Accepted: 11/28/2023] [Indexed: 01/05/2024] Open
Abstract
Hyperactivation of ribosome biosynthesis (RiBi) is a hallmark of cancer, and targeting ribosome biogenesis has emerged as a potential therapeutic strategy. The depletion of TAF1B, a major component of selectivity factor 1 (SL1), disrupts the pre-initiation complex, preventing RNA polymerase I from binding ribosomal DNA and inhibiting the hyperactivation of RiBi. Here, we investigate the role of TAF1B, in regulating RiBi and proliferation in stomach adenocarcinoma (STAD). We disclosed that the overexpression of TAF1B correlates with poor prognosis in STAD, and found that knocking down TAF1B effectively inhibits STAD cell proliferation and survival in vitro and in vivo. TAF1B knockdown may also induce nucleolar stress, and promote c-MYC degradation in STAD cells. Furthermore, we demonstrate that TAF1B depletion impairs rRNA gene transcription and processing, leading to reduced ribosome biogenesis. Collectively, our findings suggest that TAF1B may serve as a potential therapeutic target for STAD and highlight the importance of RiBi in cancer progression.
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Affiliation(s)
- Hang-fei Chen
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
- The 2nd Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Zhang-ping Li
- Department of Emergency Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Qi Wu
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Chun Yu
- Department of Gastroenterology, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Jing-Yi Yan
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang, China
| | - Yong-feng Bai
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Sheng-mei Zhu
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Mao-xiang Qian
- Institute of Pediatrics and Department of Hematology and Oncology, National Children's Medical Center, Children's Hospital of Fudan University, Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Ming Liu
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Li-feng Xu
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Zheng Peng
- Department of Radiation Oncology, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
| | - Feng Zhang
- The Joint Innovation Center for Engineering in Medicine, the Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou 324000, China
- The 2nd Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou 310053, China
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3
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Gavrilova AA, Fefilova AS, Vishnyakov IE, Kuznetsova IM, Turoverov KK, Uversky VN, Fonin AV. On the Roles of the Nuclear Non-Coding RNA-Dependent Membrane-Less Organelles in the Cellular Stress Response. Int J Mol Sci 2023; 24:ijms24098108. [PMID: 37175815 PMCID: PMC10179167 DOI: 10.3390/ijms24098108] [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: 03/26/2023] [Revised: 04/21/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
At the beginning of the 21st century, it became obvious that radical changes had taken place in the concept of living matter and, in particular, in the concept of the organization of intracellular space. The accumulated data testify to the essential importance of phase transitions of biopolymers (first of all, intrinsically disordered proteins and RNA) in the spatiotemporal organization of the intracellular space. Of particular interest is the stress-induced reorganization of the intracellular space. Examples of organelles formed in response to stress are nuclear A-bodies and nuclear stress bodies. The formation of these organelles is based on liquid-liquid phase separation (LLPS) of intrinsically disordered proteins (IDPs) and non-coding RNA. Despite their overlapping composition and similar mechanism of formation, these organelles have different functional activities and physical properties. In this review, we will focus our attention on these membrane-less organelles (MLOs) and describe their functions, structure, and mechanism of formation.
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Affiliation(s)
- Anastasia A Gavrilova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia
| | - Anna S Fefilova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia
| | - Innokentii E Vishnyakov
- Group of Molecular Cytology of Prokaryotes and Bacterial Invasion, Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia
| | - Irina M Kuznetsova
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia
| | - Konstantin K Turoverov
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Alexander V Fonin
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, 194064 St. Petersburg, Russia
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4
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Miyake T, McDermott JC. Re-organization of nucleolar architecture in myogenic differentiation. J Cell Sci 2023; 136:286887. [PMID: 36727534 DOI: 10.1242/jcs.260496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 01/19/2023] [Indexed: 02/03/2023] Open
Abstract
Myogenesis, the process of muscle differentiation, requires an extensive remodeling of the cellular transcriptome and proteome. Whereas the transcriptional program underpinning myogenesis is well characterized, the required adaptation in protein synthesis is incompletely understood. Enhanced protein synthesis necessitates ribosome biogenesis at the nucleolus. Nucleolar size and activity are inextricably linked with altered gene expression. Here, we report changes in nucleolar morphology and function during myogenic differentiation. Immunofluorescence analysis revealed alterations in nucleolar morphology that were dependent on the cellular state - proliferative or quiescent myogenic progenitors (myoblasts or reserve cells) contained multiple small nucleoli with a characteristic spherical shape, whereas multinucleated myotubes typically contained one large, often irregularly shaped nucleolus. These morphological alterations are consistent with changes to nucleolar phase separation properties. Re-organization of the nucleolar structure was correlated with enhanced rRNA production and protein translation. Inhibition of mTOR signaling with rapamycin perturbed nucleolar re-organization. Conversely, hyperactivated mTOR enhanced alterations in nucleolar morphology. These findings support the idea that there is an mTOR dependent re-organization of nucleolar structure during myogenesis, enhancing our understanding of myogenesis and possibly facilitating new approaches to therapeutic interventions in muscle pathologies.
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Affiliation(s)
- Tetsuaki Miyake
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.,Muscle Health Research Centre (MHRC), York University, Toronto, ON M3J 1P3, Canada.,Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON M3J 1P3, Canada
| | - John C McDermott
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.,Muscle Health Research Centre (MHRC), York University, Toronto, ON M3J 1P3, Canada.,Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON M3J 1P3, Canada
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5
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Islas-Morales PF, Cárdenas A, Mosqueira MJ, Jiménez-García LF, Voolstra CR. Ultrastructural and proteomic evidence for the presence of a putative nucleolus in an Archaeon. Front Microbiol 2023; 14:1075071. [PMID: 36819014 PMCID: PMC9932318 DOI: 10.3389/fmicb.2023.1075071] [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: 11/02/2022] [Accepted: 01/02/2023] [Indexed: 02/05/2023] Open
Abstract
Nucleoli are subcellular compartments where transcription and maturation of pre-ribosomal RNAs occur. While the transcription of ribosomal RNAs is common to all living cells, the presence and ultrastructure of nucleoli has been only documented in eukaryotes. Asgard-Archaea, the closest prokaryotic relatives of eukaryotes, and their near relatives TACK-Archaea have homologs of nucleolar proteins and RNAs in their genome, but the cellular organization of both is largely unexplored. Here we provide ultrastructural and molecular evidence for the presence of putative nucleolus-like subcellular domains in the TACK crenarchaeon Saccharolobus solfataricus (formerly known as Sulfolobus solfataricus). Transmission electron microscopy (TEM) revealed consistent electron-dense fibro-granular compartments, also positive to the specific silver staining for nucleolar organizer regions (AgNOR). TEM also confirmed that ribosomal DNA (rDNA) is spatially distributed in non-random, clustered arrays underlying fine structures, as observed by ultrastructural in situ hybridization (UISH). To further explore these observations, proteomic sequencing of isolated bands from AgNOR-stained protein gels was conducted and compared against a compiled inventory of putative nucleolar homologs from the S. solfataricus P1 genome. Sequenced AgNOR-sensitive peptides encoded homologs of eukaryotic nucleoli proteins, enriched for nucleolus-related functions. Our results provide first evidence that subcellular domains of nucleolar-like nature are not exclusive to eukaryotes. Based on our data, we propose a model for a putative nucleolus in S. solfataricus. Whereas technical limitations and further aspects remain a matter for future functional studies, our data supports the origin of nucleoli within the common ancestor of Eukarya and TACK-Archaea, based on a two-domain tree of life.
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Affiliation(s)
- Parsifal F. Islas-Morales
- Programa de Doctorado en Ciencias Biomédicas, Facultad de Medicina, UNAM, Mexico City, Mexico,UNESCO Chair on Science Diplomacy and Scientific Heritage, Instituto de Biología, UNAM, Mexico City, Mexico,Red Sea Research Center (RSRC), Biological, Environmental Sciences, and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Anny Cárdenas
- Red Sea Research Center (RSRC), Biological, Environmental Sciences, and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia,Department of Biology, University of Konstanz, Konstanz, Germany,Department of Biology, American University, Washington, DC, United States
| | - María J. Mosqueira
- Red Sea Research Center (RSRC), Biological, Environmental Sciences, and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia,NEOM, Saudi Arabia
| | - Luis Felipe Jiménez-García
- Programa de Doctorado en Ciencias Biomédicas, Facultad de Medicina, UNAM, Mexico City, Mexico,Department of Cell Biology, Faculty of Sciences, UNAM, Mexico City, Mexico,*Correspondence: Luis Felipe Jiménez-García, ✉
| | - Christian R. Voolstra
- Red Sea Research Center (RSRC), Biological, Environmental Sciences, and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia,Department of Biology, University of Konstanz, Konstanz, Germany,Christian R. Voolstra, ✉
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6
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Stamatiou K, Chmielewska A, Ohta S, Earnshaw WC, Vagnarelli P. CCDC86 is a novel Ki-67-interacting protein important for cell division. J Cell Sci 2023; 136:286751. [PMID: 36695333 PMCID: PMC10022746 DOI: 10.1242/jcs.260391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 12/08/2022] [Indexed: 01/26/2023] Open
Abstract
The chromosome periphery is a network of proteins and RNAs that coats the outer surface of mitotic chromosomes. Despite the identification of new components, the functions of this complex compartment are poorly characterised. In this study, we identified a novel chromosome periphery-associated protein, CCDC86 (also known as cyclon). Using a combination of RNA interference, microscopy and biochemistry, we studied the functions of CCDC86 in mitosis. CCDC86 depletion resulted in partial disorganisation of the chromosome periphery with alterations in the localisation of Ki-67 (also known as MKI67) and nucleolin (NCL), and the formation of abnormal cytoplasmic aggregates. Furthermore, CCDC86-depleted cells displayed errors in chromosome alignment, altered spindle length and increased apoptosis. These results suggest that, within the chromosome periphery, different subcomplexes that include CCDC86, nucleolin and B23 (nucleophosmin or NPM1) are required for mitotic spindle regulation and correct kinetochore-microtubule attachments, thus contributing to chromosome segregation in mitosis. Moreover, we identified CCDC86 as a MYCN-regulated gene, the expression levels of which represent a powerful marker for prognostic outcomes in neuroblastoma.
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Affiliation(s)
- Konstantinos Stamatiou
- College of Health, Medicine and Life Sciences, Department of Life Sciences, Brunel University London, London UB8 3PH, UK
| | - Aldona Chmielewska
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Shinya Ohta
- Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-Ku, Sapporo 060-0815, Japan
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Paola Vagnarelli
- College of Health, Medicine and Life Sciences, Department of Life Sciences, Brunel University London, London UB8 3PH, UK
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7
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Lacroix E, Audas TE. Keeping up with the condensates: The retention, gain, and loss of nuclear membrane-less organelles. Front Mol Biosci 2022; 9:998363. [PMID: 36203874 PMCID: PMC9530788 DOI: 10.3389/fmolb.2022.998363] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/19/2022] [Indexed: 12/04/2022] Open
Abstract
In recent decades, a growing number of biomolecular condensates have been identified in eukaryotic cells. These structures form through phase separation and have been linked to a diverse array of cellular processes. While a checklist of established membrane-bound organelles is present across the eukaryotic domain, less is known about the conservation of membrane-less subcellular structures. Many of these structures can be seen throughout eukaryotes, while others are only thought to be present in metazoans or a limited subset of species. In particular, the nucleus is a hub of biomolecular condensates. Some of these subnuclear domains have been found in a broad range of organisms, which is a characteristic often attributed to essential functionality. However, this does not always appear to be the case. For example, the nucleolus is critical for ribosomal biogenesis and is present throughout the eukaryotic domain, while the Cajal bodies are believed to be similarly conserved, yet these structures are dispensable for organismal survival. Likewise, depletion of the Drosophila melanogaster omega speckles reduces viability, despite the apparent absence of this domain in higher eukaryotes. By reviewing primary research that has analyzed the presence of specific condensates (nucleoli, Cajal bodies, amyloid bodies, nucleolar aggresomes, nuclear speckles, nuclear paraspeckles, nuclear stress bodies, PML bodies, omega speckles, NUN bodies, mei2 dots) in a cross-section of organisms (e.g., human, mouse, D. melanogaster, Caenorhabditis elegans, yeast), we adopt a human-centric view to explore the emergence, retention, and absence of a subset of nuclear biomolecular condensates. This overview is particularly important as numerous biomolecular condensates have been linked to human disease, and their presence in additional species could unlock new and well characterized model systems for health research.
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Affiliation(s)
- Emma Lacroix
- 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
| | - 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: Timothy E. Audas,
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8
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Lee TA, Han H, Polash A, Cho SK, Lee JW, Ra EA, Lee E, Park A, Kang S, Choi JL, Kim JH, Lee JE, Min KW, Yang SW, Hafner M, Lee I, Yoon JH, Lee S, Park B. The nucleolus is the site for inflammatory RNA decay during infection. Nat Commun 2022; 13:5203. [PMID: 36057640 PMCID: PMC9440930 DOI: 10.1038/s41467-022-32856-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 08/16/2022] [Indexed: 11/12/2022] Open
Abstract
Inflammatory cytokines are key signaling molecules that can promote an immune response, thus their RNA turnover must be tightly controlled during infection. Most studies investigate the RNA decay pathways in the cytosol or nucleoplasm but never focused on the nucleolus. Although this organelle has well-studied roles in ribosome biogenesis and cellular stress sensing, the mechanism of RNA decay within the nucleolus is not completely understood. Here, we report that the nucleolus is an essential site of inflammatory pre-mRNA instability during infection. RNA-sequencing analysis reveals that not only do inflammatory genes have higher intronic read densities compared with non-inflammatory genes, but their pre-mRNAs are highly enriched in nucleoli during infection. Notably, nucleolin (NCL) acts as a guide factor for recruiting cytosine or uracil (C/U)-rich sequence-containing inflammatory pre-mRNAs and the Rrp6-exosome complex to the nucleolus through a physical interaction, thereby enabling targeted RNA delivery to Rrp6-exosomes and subsequent degradation. Consequently, Ncl depletion causes aberrant hyperinflammation, resulting in a severe lethality in response to LPS. Importantly, the dynamics of NCL post-translational modifications determine its functional activity in phases of LPS. This process represents a nucleolus-dependent pathway for maintaining inflammatory gene expression integrity and immunological homeostasis during infection. The nucleolus is the traditional site for ribosomal RNA biogenesis. Here, the authors find that the nucleolus is a site of inflammatory pre-mRNA turnover and elucidated how immune homeostasis can be maintained by controlling inflammatory gene expression.
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Affiliation(s)
- Taeyun A Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Heonjong Han
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.,Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.,Division of Tumor Immunology, Research Institute, National Cancer Center, Goyang, South Korea
| | - Ahsan Polash
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute for Arthritis and Musculoskeletal and Skin Disease, National Institutes of Health, Bethesda, MD, USA
| | - Seok Keun Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Ji Won Lee
- Department of Biology, College of Natural Sciences, Gangneung-Wonju National University, Gangneung, South Korea
| | - Eun A Ra
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Eunhye Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Areum Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Sujin Kang
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Junhee L Choi
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Ji Hyun Kim
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Ji Eun Lee
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea.,Samsung Genome Institute (SGI), Samsung Medical Center, Seoul, South Korea
| | - Kyung-Won Min
- Department of Biology, College of Natural Sciences, Gangneung-Wonju National University, Gangneung, South Korea.,Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA
| | - Seong Wook Yang
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Markus Hafner
- Laboratory of Muscle Stem Cells and Gene Regulation, National Institute for Arthritis and Musculoskeletal and Skin Disease, National Institutes of Health, Bethesda, MD, USA
| | - Insuk Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Je-Hyun Yoon
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA.
| | - Sungwook Lee
- Division of Tumor Immunology, Research Institute, National Cancer Center, Goyang, South Korea.
| | - Boyoun Park
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
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9
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Improved Fluorescent Proteins for Dual-Colour Post-Embedding CLEM. Cells 2022; 11:cells11071077. [PMID: 35406640 PMCID: PMC8997867 DOI: 10.3390/cells11071077] [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: 02/16/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 02/04/2023] Open
Abstract
Post-embedding correlative light and electron microscopy (CLEM) has the advantage of high-precision registration and enables light and electron microscopy imaging of the same slice. However, its broad application has been hampered by the limited available fluorescent proteins (FPs) and a low signal-to-background ratio (SBR). Here, we developed a green photoswitchable FP, mEosEM-E with substantially high on/off contrast in EM samples embedded in Epon resin, which maximally preserves cellular structures but quenches the fluorescence of FPs. Taking advantage of the photoswitching property of mEosEM-E, the autofluorescence background from the resin was significantly reduced by a subtraction-based CLEM (sCLEM) method. Meanwhile, we identified a red fluorescent protein (RFP) mScarlet-H that exhibited higher brightness and SBR in resin than previously reported RFPs. With mEosEM-E and mScarlet-H, dual-colour post-Epon-embedding CLEM images with high SBR and no cross-talk signal were successfully performed to reveal the organization of nucleolar proteins. Moreover, a dissection of the influences of different EM sample preparation steps on the fluorescence preservation for several RFPs provides useful guidance for further probe development.
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10
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Yadav U, Verma M, Abbas Z, Sivakumar S, Patra AK. An emissive dual-sensitized bimetallic Eu 2III-bioprobe: design strategy, biological interactions, and nucleolus staining studies. NEW J CHEM 2022. [DOI: 10.1039/d2nj02853k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A dual sensitized Eu2III–bioprobe (1) offers incredible opportunities for fine-tuning and exploring a strongly luminescent probe as a nucleolus staining agent.
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Affiliation(s)
- Usha Yadav
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Madhu Verma
- Department of Chemical Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Zafar Abbas
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Sri Sivakumar
- Department of Chemical Engineering and Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Ashis K. Patra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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11
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Sanchez-Martin V, Schneider DA, Ortiz-Gonzalez M, Soriano-Lerma A, Linde-Rodriguez A, Perez-Carrasco V, Gutierrez-Fernandez J, Cuadros M, González C, Soriano M, Garcia-Salcedo JA. Targeting ribosomal G-quadruplexes with naphthalene-diimides as RNA polymerase I inhibitors for colorectal cancer treatment. Cell Chem Biol 2021; 28:1590-1601.e4. [PMID: 34166611 DOI: 10.1016/j.chembiol.2021.05.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/05/2021] [Accepted: 05/27/2021] [Indexed: 12/11/2022]
Abstract
Guanine quadruplexes (G4s) are non-canonical nucleic acid structures commonly found in regulatory genomic regions. G4 targeting has emerged as a therapeutic approach in cancer. We have screened naphthalene-diimides (NDIs), a class of G4 ligands, in a cellular model of colorectal cancer (CRC). Here, we identify the leading compound T5 with a potent and selective inhibition of cell growth by high-affinity binding to G4s in ribosomal DNA, impairing RNA polymerase I (Pol I) elongation. Consequently, T5 induces a rapid inhibition of Pol I transcription, nucleolus disruption, proteasome-dependent Pol I catalytic subunit A degradation and autophagy. Moreover, we attribute the higher selectivity of carbohydrate-conjugated T5 for tumoral cells to its preferential uptake through the overexpressed glucose transporter 1. Finally, we succinctly demonstrate that T5 could be explored as a therapeutic agent in a patient cohort with CRC. Therefore, we report a mode of action for these NDIs involving ribosomal G4 targeting.
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Affiliation(s)
- Victoria Sanchez-Martin
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Microbiology Unit, Biosanitary Research Institute IBS.Granada, University Hospital Virgen de las Nieves, Granada 18014, Spain; Department of Biochemistry, Molecular Biology III and Immunology, University of Granada, Granada 18016, Spain
| | - David A Schneider
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Matilde Ortiz-Gonzalez
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Centre for Intensive Mediterranean Agrosystems and Agri-food Biotechnology (CIAIMBITAL), University of Almeria, Almeria 04001, Spain
| | - Ana Soriano-Lerma
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Department of Physiology, University of Granada, Granada 18011, Spain
| | - Angel Linde-Rodriguez
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Microbiology Unit, Biosanitary Research Institute IBS.Granada, University Hospital Virgen de las Nieves, Granada 18014, Spain
| | - Virginia Perez-Carrasco
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Microbiology Unit, Biosanitary Research Institute IBS.Granada, University Hospital Virgen de las Nieves, Granada 18014, Spain
| | - Jose Gutierrez-Fernandez
- Microbiology Unit, Biosanitary Research Institute IBS.Granada, University Hospital Virgen de las Nieves, Granada 18014, Spain; Department of Microbiology, University of Granada, Granada 18011, Spain
| | - Marta Cuadros
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Department of Biochemistry, Molecular Biology III and Immunology, University of Granada, Granada 18016, Spain
| | - Carlos González
- Instituto de Química Física "Rocasolano", CSIC, Madrid 28006, Spain
| | - Miguel Soriano
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Centre for Intensive Mediterranean Agrosystems and Agri-food Biotechnology (CIAIMBITAL), University of Almeria, Almeria 04001, Spain
| | - Jose A Garcia-Salcedo
- GENYO. Centre for Genomics and Oncological Research: Pfizer/University of Granada/Andalusian Regional Government, Granada 18016, Spain; Microbiology Unit, Biosanitary Research Institute IBS.Granada, University Hospital Virgen de las Nieves, Granada 18014, Spain.
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12
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Tchurikov NA, Kravatsky YV. The Role of rDNA Clusters in Global Epigenetic Gene Regulation. Front Genet 2021; 12:730633. [PMID: 34531902 PMCID: PMC8438155 DOI: 10.3389/fgene.2021.730633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/02/2021] [Indexed: 12/26/2022] Open
Abstract
The regulation of gene expression has been studied for decades, but the underlying mechanisms are still not fully understood. As well as local and distant regulation, there are specific mechanisms of regulation during development and physiological modulation of gene activity in differentiated cells. Current research strongly supports a role for the 3D chromosomal structure in the regulation of gene expression. However, it is not known whether the genome structure reflects the formation of active or repressed chromosomal domains or if these structures play a primary role in the regulation of gene expression. During early development, heterochromatinization of ribosomal DNA (rDNA) is coupled with silencing or activation of the expression of different sets of genes. Although the mechanisms behind this type of regulation are not known, rDNA clusters shape frequent inter-chromosomal contacts with a large group of genes controlling development. This review aims to shed light on the involvement of clusters of ribosomal genes in the global regulation of gene expression. We also discuss the possible role of RNA-mediated and phase-separation mechanisms in the global regulation of gene expression by nucleoli.
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Affiliation(s)
- Nickolai A Tchurikov
- Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Moscow, Russia
| | - Yuri V Kravatsky
- Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Moscow, Russia
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13
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Thoms HC, Stark LA. The NF-κB Nucleolar Stress Response Pathway. Biomedicines 2021; 9:biomedicines9091082. [PMID: 34572268 PMCID: PMC8471347 DOI: 10.3390/biomedicines9091082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/09/2021] [Accepted: 08/20/2021] [Indexed: 12/20/2022] Open
Abstract
The nuclear organelle, the nucleolus, plays a critical role in stress response and the regulation of cellular homeostasis. P53 as a downstream effector of nucleolar stress is well defined. However, new data suggests that NF-κB also acts downstream of nucleolar stress to regulate cell growth and death. In this review, we will provide insight into the NF-κB nucleolar stress response pathway. We will discuss apoptosis mediated by nucleolar sequestration of RelA and new data demonstrating a role for p62 (sequestosome (SQSTM1)) in this process. We will also discuss activation of NF-κB signalling by degradation of the RNA polymerase I (PolI) complex component, transcription initiation factor-IA (TIF-IA (RRN3)), and contexts where TIF-IA-NF-κB signalling may be important. Finally, we will discuss how this pathway is targeted by aspirin to mediate apoptosis of colon cancer cells.
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14
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De Nicola I, Guerrieri AN, Penzo M, Ceccarelli C, De Leo A, Trerè D, Montanaro L. Combined expression levels of KDM2A and KDM2B correlate with nucleolar size and prognosis in primary breast carcinomas. Histol Histopathol 2020; 35:1181-1187. [PMID: 32901907 DOI: 10.14670/hh-18-248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ribosome biogenesis is a fine-tuned cellular process and its deregulation is linked to cancer progression: tumors characterized by an intense ribosome biogenesis often display a more aggressive behavior. Ribosomal RNA (rRNA) synthesis is controlled at several levels, the higher one being the epigenetic regulation of the condensation of chromatin portions containing rRNA genes. KDM2A and KDM2B (Lysine (K)-specific demethylase 2A / B) are histone demethylases modulating the accessibility of ribosomal genes, thereby regulating their transcription. Both enzymes are able to demethylate lysins at relevant sites (e.g. K4, K36) on histone H3. We previously demonstrated that KDM2B is one of the factors regulating ribosome biogenesis in human breast cancer. In this study we aimed to define the combined contribution of KDM2A and KDM2B to breast cancer outcome. KDM2A and KDM2B mRNA levels, nucleolar area as a marker of ribosome biogenesis, and patients' prognosis were retrospectively assessed in a series of primary breast carcinomas. We observed that tumors characterized by reduced levels of both KDM2A and KDM2B displayed a particularly aggressive clinical behavior and increased nucleolar size. Our results suggest that KDM2A and KDM2B may cooperate in regulating ribosome biogenesis thus influencing the biological behavior and clinical outcome of human breast cancers.
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Affiliation(s)
- Igor De Nicola
- S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Ania Naila Guerrieri
- Department of Experimental, Diagnostic and Specialty medicine (DIMES), Alma Mater Studiorum - University of Bologna, Bologna, Italy.,Center for Applied Biomedical Research (CRBA), Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Marianna Penzo
- Department of Experimental, Diagnostic and Specialty medicine (DIMES), Alma Mater Studiorum - University of Bologna, Bologna, Italy.,Center for Applied Biomedical Research (CRBA), Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Claudio Ceccarelli
- Department of Experimental, Diagnostic and Specialty medicine (DIMES), Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Antonio De Leo
- Department of Experimental, Diagnostic and Specialty medicine (DIMES), Alma Mater Studiorum - University of Bologna, Bologna, Italy.,Pathology Unit, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy
| | - Davide Trerè
- Department of Experimental, Diagnostic and Specialty medicine (DIMES), Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Lorenzo Montanaro
- Department of Experimental, Diagnostic and Specialty medicine (DIMES), Alma Mater Studiorum - University of Bologna, Bologna, Italy.,Center for Applied Biomedical Research (CRBA), Alma Mater Studiorum - University of Bologna, Bologna, Italy.
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15
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Engbrecht M, Mangerich A. The Nucleolus and PARP1 in Cancer Biology. Cancers (Basel) 2020; 12:cancers12071813. [PMID: 32640701 PMCID: PMC7408768 DOI: 10.3390/cancers12071813] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/26/2020] [Accepted: 07/01/2020] [Indexed: 12/13/2022] Open
Abstract
The nucleolus has been known for a long time to fulfill crucial functions in ribosome biogenesis, of which cancer cells can become addicted to in order to produce sufficient amounts of proteins for cell proliferation. Recently, the nucleolus has emerged as a central regulatory hub in many other cancer-relevant processes, including stress sensing, DNA damage response, cell cycle control, and proteostasis. This fostered the idea that nucleolar processes can be exploited in cancer therapy. Interestingly, a significant proportion of poly(ADP-ribose) polymerase 1 (PARP1) molecules are localized in the nucleolus and PARP1 also plays crucial roles in many processes that are important in cancer biology, including genome maintenance, replication, transcription, and chromatin remodeling. Furthermore, during the last years, PARP1 came into focus in oncology since it represents a promising target of pharmacological PARP inhibitors in various types of cancers. Here, we provide an overview of our current understanding on the role of PARP1 in nucleolar functions and discuss potential implications in cancer biology and therapy.
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16
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Nucleolus structural integrity during the first meiotic prophase in rat spermatocytes. Exp Cell Res 2019; 383:111587. [PMID: 31454492 DOI: 10.1016/j.yexcr.2019.111587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 12/19/2022]
Abstract
A typical nucleolus structure is shaped by three components. A meshwork of fine fibers forming the fibrillar center (FC) is surrounded by densely packed fibers forming the dense fibrillar component (DFC). Meanwhile, wrapping the FC and DFC is the granular component (GC). During the mitotic prophase, the nucleolus undergoes disassembling of its components. On the contrary, throughout the first meiotic prophase that occurs in the cells of the germ line, small nucleoli are assembled into one nucleolus by the end of the prophase. These nucleoli are transcriptionally active, suggesting that they are fully functional. Electron microscopy analysis has suggested that these nucleoli display their three main components but a typical organization has not been observed. Here, by immunolabeling and electron microscopy, we show that the nucleolus has its three main components. The GC is interlaced with the DFC and is not as well defined as previously thought during leptotene and zygotene stage.
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17
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Chen J, Stark LA. Insights into the Relationship between Nucleolar Stress and the NF-κB Pathway. Trends Genet 2019; 35:768-780. [PMID: 31434627 DOI: 10.1016/j.tig.2019.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
The nuclear organelle the nucleolus and the transcription factor nuclear factor of κ-light-chain-enhancer of activated B cells (NF-κB) are both central to the control of cellular homeostasis, dysregulated in common diseases and implicated in the ageing process. Until recently, it was believed that they acted independently to regulate homeostasis in health and disease. However, there is an emerging body of evidence suggesting that nucleoli and NF-κB signalling converge at multiple levels. Here we will review current understanding of this crosstalk. We will discuss activation of the NF-κB pathway by nucleolar stress and induction of apoptosis by nucleolar sequestration of NF-κB/RelA. We will also discuss the role of TIF-IA, COMMD1, and nucleophosmin, which are key players in this crosstalk, and the therapeutic relevance, particularly with respect to the antitumour effects of aspirin.
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Affiliation(s)
- Jingyu Chen
- University of Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh, Scotland EH4 2XU, UK
| | - Lesley A Stark
- University of Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh, Scotland EH4 2XU, UK.
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18
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Kim TK, Lee BW, Fujii F, Kim JK, Pack CG. Physicochemical Properties of Nucleoli in Live Cells Analyzed by Label-Free Optical Diffraction Tomography. Cells 2019; 8:cells8070699. [PMID: 31295945 PMCID: PMC6679011 DOI: 10.3390/cells8070699] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/27/2019] [Accepted: 07/09/2019] [Indexed: 12/15/2022] Open
Abstract
The cell nucleus is three-dimensionally and dynamically organized by nuclear components with high molecular density, such as chromatin and nuclear bodies. The structure and functions of these components are represented by the diffusion and interaction of related factors. Recent studies suggest that the nucleolus can be assessed using various protein probes, as the probes are highly mobile in this organelle, although it is known that they have a densely packed structure. However, physicochemical properties of the nucleolus itself, such as molecular density and volume when cellular conditions are changed, are not yet fully understood. In this study, physical parameters such as the refractive index (RI) and volume of the nucleoli in addition to the diffusion coefficient (D) of fluorescent probe protein inside the nucleolus are quantified and compared by combining label-free optical diffraction tomography (ODT) with confocal laser scanning microscopy (CLSM)-based fluorescence correlation spectroscopy (FCS). 3D evaluation of RI values and corresponding RI images of nucleoli in live HeLa cells successfully demonstrated varying various physiological conditions. Our complimentary method suggests that physical property of the nucleolus in live cell is sensitive to ATP depletion and transcriptional inhibition, while it is insensitive to hyper osmotic pressure when compared with the cytoplasm and nucleoplasm. The result demonstrates that the nucleolus has unique physicochemical properties when compared with other cellular components.
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Affiliation(s)
- Tae-Keun Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea
| | - Byong-Wook Lee
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea
| | - Fumihiko Fujii
- Division of Physical Pharmacy, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan
| | - Jun Ki Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea.
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea.
| | - Chan-Gi Pack
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Korea.
- Department of Convergence Medicine, University of Ulsan College of Medicine, Seoul 05505, Korea.
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19
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Latonen L. Phase-to-Phase With Nucleoli - Stress Responses, Protein Aggregation and Novel Roles of RNA. Front Cell Neurosci 2019; 13:151. [PMID: 31080406 PMCID: PMC6497782 DOI: 10.3389/fncel.2019.00151] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 04/08/2019] [Indexed: 12/11/2022] Open
Abstract
Protein- and RNA-containing foci and aggregates are a hallmark of many age- and mutation-related neurodegenerative diseases. This article focuses on the role the nucleolus has as a hub in macromolecule regulation in the mammalian nucleus. The nucleolus has a well-established role in ribosome biogenesis and functions in several types of cellular stress responses. In addition to known reactions to DNA damaging and transcription inhibiting stresses, there is an emerging role of the nucleolus especially in responses to proteotoxic stress such as heat shock and inhibition of proteasome function. The nucleolus serves as an active regulatory site for detention of extranucleolar proteins. This takes place in nucleolar cavities and manifests in protein and RNA collections referred to as intranucleolar bodies (INBs), nucleolar aggresomes or amyloid bodies (A-bodies), depending on stress type, severity of accumulation, and material propensities of the macromolecular collections. These indicate a relevance of nucleolar function and regulation in neurodegeneration-related cellular events, but also provide surprising connections with cancer-related pathways. Yet, the molecular mechanisms governing these processes remain largely undefined. In this article, the nucleolus as the site of protein and RNA accumulation and as a possible protective organelle for nuclear proteins during stress is viewed. In addition, recent evidence of liquid-liquid phase separation (LLPS) and liquid-solid phase transition in the formation of nucleoli and its stress responses, respectively, are discussed, along with the increasingly indicated role and open questions for noncoding RNA species in these events.
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Affiliation(s)
- Leena Latonen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
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20
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Wang M, Bokros M, Theodoridis PR, Lee S. Nucleolar Sequestration: Remodeling Nucleoli Into Amyloid Bodies. Front Genet 2019; 10:1179. [PMID: 31824572 PMCID: PMC6881480 DOI: 10.3389/fgene.2019.01179] [Citation(s) in RCA: 15] [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: 07/20/2019] [Accepted: 10/24/2019] [Indexed: 01/14/2023] Open
Abstract
This year marks the 20th anniversary of the discovery that the nucleolus can temporarily immobilize proteins, a process known as nucleolar sequestration. This review reflects on the progress made to understand the physiological roles of nucleolar sequestration and the mechanisms involved in the immobilization of proteins. We discuss how protein immobilization can occur through a highly choreographed amyloidogenic program that converts the nucleolus into a large fibrous organelle with amyloid-like characteristics called the amyloid body (A-body). We propose a working model of A-body biogenesis that includes a role for low-complexity ribosomal intergenic spacer RNA (rIGSRNA) and a discrete peptide sequence, the amyloid-converting motif (ACM), found in many proteins that undergo immobilization. Amyloid bodies provide a unique model to study the multistep assembly of a membraneless compartment and may provide alternative insights into the pathological amyloidogenesis involved in neurological disorders.
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Affiliation(s)
- Miling Wang
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Michael Bokros
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Phaedra Rebecca Theodoridis
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Stephen Lee
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, FL, United States
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL, United States
- Department of Urology, Miller School of Medicine, University of Miami, FL, United States
- *Correspondence: Stephen Lee,
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21
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Scherrer K. Primary transcripts: From the discovery of RNA processing to current concepts of gene expression - Review. Exp Cell Res 2018; 373:1-33. [PMID: 30266658 DOI: 10.1016/j.yexcr.2018.09.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/12/2018] [Accepted: 09/17/2018] [Indexed: 12/15/2022]
Abstract
The main purpose of this review is to recall for investigators - and in particular students -, some of the early data and concepts in molecular genetics and biology that are rarely cited in the current literature and are thus invariably overlooked. There is a growing tendency among editors and reviewers to consider that only data produced in the last 10-20 years or so are pertinent. However this is not the case. In exact science, sound data and lucid interpretation never become obsolete, and even if forgotten, will resurface sooner or later. In the field of gene expression, covered in the present review, recent post-genomic data have indeed confirmed many of the earlier results and concepts developed in the mid-seventies, well before the start of the recombinant DNA revolution. Human brains and even the most powerful computers, have difficulty in handling and making sense of the overwhelming flow of data generated by recent high-throughput technologies. This was easier when low throughput, more integrative methods based on biochemistry and microscopy dominated biological research. Nowadays, the need for organising concepts is ever more important, otherwise the mass of available data can generate only "building ruins" - the bricks without an architect. Concepts such as pervasive transcription of genomes, large genomic domains, full domain transcripts (FDTs) up to 100 kb long, the prevalence of post-transcriptional events in regulating eukaryotic gene expression, and the 3D-genome architecture, were all developed and discussed before 1990, and are only now coming back into vogue. Thus, to review the impact of earlier concepts on later developments in the field, I will confront former and current data and ideas, including a discussion of old and new methods. Whenever useful, I shall first briefly report post-genomic developments before addressing former results and interpretations. Equally important, some of the terms often used sloppily in scientific discussions will be clearly defined. As a basis for the ensuing discussion, some of the issues and facts related to eukaryotic gene expression will first be introduced. In chapter 2 the evolution in perception of biology over the last 60 years and the impact of the recombinant DNA revolution will be considered. Then, in chapter 3 data and theory concerning the genome, gene expression and genetics will be reviewed. The experimental and theoretical definition of the gene will be discussed before considering the 3 different types of genetic information - the "Triad" - and the importance of post-transcriptional regulation of gene expression in the light of the recent finding that 90% of genomic DNA seems to be transcribed. Some previous attempts to provide a conceptual framework for these observations will be recalled, in particular the "Cascade Regulation Hypothesis" (CRH) developed in 1967-85, and the "Gene and Genon" concept proposed in 2007. A knowledge of the size of primary transcripts is of prime importance, both for experimental and theoretical reasons, since these molecules represent the primary units of the "RNA genome" on which most of the post-transcriptional regulation of gene expression occurs. In chapter 4, I will first discuss some current post-genomic topics before summarising the discovery of the high Mr-RNA transcripts, and the investigation of their processing spanning the last 50 years. Since even today, a consensus concerning the real form of primary transcripts in eukaryotic cells has not yet been reached, I will refer to the viral and specialized cellular models which helped early on to understand the mechanisms of RNA processing and differential splicing which operate in cells and tissues. As a well-studied example of expression and regulation of a specific cellular gene in relation to differentiation and pathology, I will discuss the early and recent work on expression of the globin genes in nucleated avian erythroblasts. An important concept is that the primary transcript not only embodies protein-coding information and regulation of its expression, but also the 3D-structure of the genomic DNA from which it was derived. The wealth of recent post-genomic data published in this field emphasises the importance of a fundamental principle of genome organisation and expression that has been overlooked for years even though it was already discussed in the 1970-80ties. These issues are addressed in chapter 5 which focuses on the involvement of the nuclear matrix and nuclear architecture in DNA and RNA biology. This section will make reference to the Unified Matrix Hypothesis (UMH), which was the first molecular model of the 3D organisation of DNA and RNA. The chapter on the "RNA-genome and peripheral memories" discusses experimental data on the ribonucleoprotein complexes containing pre-mRNA (pre-mRNPs) and mRNA (mRNPs) which are organised in nuclear and cytoplasmic spaces respectively. Finally, "Outlook " will enumerate currently unresolved questions in the field, and will propose some ideas that may encourage further investigation, and comprehension of available experimental data still in need of interpretation. In chapter 8, some propositions and paradigms basic to the authors own analysis are discussed. "In conclusion" the raison d'être of this review is recalled and positioned within the overall framework of scientific endeavour.
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Affiliation(s)
- Klaus Scherrer
- Institute Jacques Monod, CNRS, University Paris Diderot, Paris, France.
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22
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Villegas-Mercado CE, Agredano-Moreno LT, Bermúdez M, Segura-Valdez ML, Arzate H, Del Toro-Rangel EF, Jiménez-García LF. Cementum protein 1 transfection does not lead to ultrastructural changes in nucleolar organization of human gingival fibroblasts. J Periodontal Res 2018; 53:636-642. [PMID: 29704248 DOI: 10.1111/jre.12553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND OBJECTIVE Transfection of cementum protein 1 (CEMP1) into human gingival fibroblasts (HGFs) notably increases cell metabolism and results in overexpression of molecules related to biomineralization at transcriptional and protein levels. Therefore, HGF-CEMP1 cells are considered as putative cementoblasts. This represents a significant advance in periodontal research because cementum neoformation is a key event in periodontal regeneration. In addition, it is well known that important changes in cell metabolism and protein expression are related to nucleolar structure and the function of this organelle, which is implicated in ribosome biogenesis. The aim of this study was to determine the effect of transfecting CEMP1 gene in human HGF on the ultrastructure of the nucleolus. MATERIAL AND METHODS Cells were processed using the conventional technique for transmission electron microscopy, fixed with glutaraldehyde, postfixed with osmium tetraoxide, and embedded in epoxy resin. Semi-thin sections were stained with Toluidine blue and observed by light microscopy. Thin sections were stained with uranyl acetate and lead citrate. For ribonucleoprotein detection, the staining method based on the regressive effect of EDTA was used. In addition, the osmium ammine technique was used for specific staining of DNA. RESULTS The results obtained in this study suggest that transfection of CEMP1 into HGFs does not produce changes in the general nucleolar ultrastructure because the different components of the organelle are present as fibrillary centers, and dense fibrillar and granular components compared with the control. CONCLUSION The transfection of CEMP1 into HGFs allows these cells to perform cementoblast-like functions without alteration of the ultrastructure of the nucleolus, evaluated by the presence of the different compartments of this organelle involved in ribosomal biogenesis.
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Affiliation(s)
- C E Villegas-Mercado
- Faculty of Sciences, Electron Microscopy Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico.,Faculty of Sciences, Department of Cell Biology, Cell Nano-Biology Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico
| | - L T Agredano-Moreno
- Faculty of Sciences, Electron Microscopy Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico.,Faculty of Sciences, Department of Cell Biology, Cell Nano-Biology Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico
| | - M Bermúdez
- School of Higher Education of Zaragoza, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico
| | - M L Segura-Valdez
- Faculty of Sciences, Electron Microscopy Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico.,Faculty of Sciences, Department of Cell Biology, Cell Nano-Biology Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico
| | - H Arzate
- Faculty of Dentistry, Periodontal Biology Laboratory, DEPeI, National Autonomous University of Mexico (UNAM), Ciudad de Mexico, Mexico
| | - E F Del Toro-Rangel
- Faculty of Sciences, Electron Microscopy Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico.,Faculty of Sciences, Department of Cell Biology, Cell Nano-Biology Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico
| | - L F Jiménez-García
- Faculty of Sciences, Electron Microscopy Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico.,Faculty of Sciences, Department of Cell Biology, Cell Nano-Biology Laboratory, National Autonomous University of México (UNAM), Ciudad de Mexico, Mexico
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23
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Abstract
There is growing evidence that transcription and nuclear organization are tightly linked. Yet, whether transcription of thousands of long noncoding RNAs (lncRNAs) could play a role in this packaging process remains elusive. Although some lncRNAs have been found to have clear roles in nuclear architecture (e.g., FIRRE, NEAT1, XIST, and others), the vast majority remain poorly understood. In this Perspective, we highlight how the act of transcription can affect nuclear architecture. We synthesize several recent findings into a proposed model where the transcription of lncRNAs can serve as guide-posts for shaping genome organization. This model is similar to the game "cat's cradle," where the shape of a string is successively changed by opening up new sites for finger placement. Analogously, transcription of lncRNAs could serve as "grip holds" for nuclear proteins to pull the genome into new positions. This model could explain general lncRNA properties such as low abundance and tissue specificity. Overall, we propose a general framework for how the act of lncRNA transcription could play a role in organizing the 3D genome.
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Affiliation(s)
- Marta Melé
- Harvard Stem Cell and Regenerative Biology Department, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, MA 02138, USA
| | - John L Rinn
- Harvard Stem Cell and Regenerative Biology Department, Harvard University, Cambridge, MA 02138, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, MA 02138, USA; Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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24
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Pastorek L, Sobol M, Hozák P. Colocalization coefficients evaluating the distribution of molecular targets in microscopy methods based on pointed patterns. Histochem Cell Biol 2016; 146:391-406. [PMID: 27460592 PMCID: PMC5037163 DOI: 10.1007/s00418-016-1467-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2016] [Indexed: 01/28/2023]
Abstract
In biomedical studies, the colocalization is commonly understood as the overlap between distinctive labelings in images. This term is usually associated especially with quantitative evaluation of the immunostaining in fluorescence microscopy. On the other hand, the evaluation of the immunolabeling colocalization in the electron microscopy images is still under-investigated and biased by the subjective and non-quantitative interpretation of the image data. We introduce a novel computational technique for quantifying the level of colocalization in pointed patterns. Our approach follows the idea included in the widely used Manders' colocalization coefficients in fluorescence microscopy and represents its counterpart for electron microscopy. In presented methodology, colocalization is understood as the product of the spatial interactions at the single-particle (single-molecule) level. Our approach extends the current significance testing in the immunoelectron microscopy images and establishes the descriptive colocalization coefficients. To demonstrate the performance of the proposed coefficients, we investigated the level of spatial interactions of phosphatidylinositol 4,5-bisphosphate with fibrillarin in nucleoli. We compared the electron microscopy colocalization coefficients with Manders' colocalization coefficients for confocal microscopy and super-resolution structured illumination microscopy. The similar tendency of the values obtained using different colocalization approaches suggests the biological validity of the scientific conclusions. The presented methodology represents a good basis for further development of the quantitative analysis of immunoelectron microscopy data and can be used for studying molecular interactions at the ultrastructural level. Moreover, this methodology can be applied also to the other super-resolution microscopy techniques focused on characterization of discrete pointed structures.
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Affiliation(s)
- Lukáš Pastorek
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
- Microscopy Centre, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Margarita Sobol
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
- Microscopy Centre, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic
| | - Pavel Hozák
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
- Microscopy Centre, Institute of Molecular Genetics ASCR v.v.i., Vídeňská 1083, 142 20, Prague 4, Czech Republic.
- Laboratory of Epigenetics of the Cell Nucleus, Division BIOCEV, Institute of Molecular Genetics of the ASCR v. v. i., Průmyslová 595, 252 50, Vestec, Czech Republic.
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25
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Andraszek K, Gryzińska M, Danielewicz A, Batkowska J, Smalec E. Age-dependent stability of nucleoli and global DNA methylation level in spermatocytes of the domestic horse (Equus caballus). CANADIAN JOURNAL OF ANIMAL SCIENCE 2016. [DOI: 10.1139/cjas-2015-0076] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the study was to determine the number and shape of nucleoli during meiosis in cells of the domestic horse. In addition, the level of global DNA methylation was determined using a quantitative technique for measuring the relative level of DNA methylation, modelled on an immunoenzymatic assay. The research was carried out on stallions belonging to two age groups (2 and 7 yr). In the cells of the 2-yr-old animals, the nucleoli were mainly of a regular shape and no fragmented nucleoli were observed. The cells of the 7-yr-old horses had a small percentage of regularly shaped nucleoli, and nucleoli with a fragmented structure were present. The study provides a basis for further research on epigenetic mechanisms in horses.
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Affiliation(s)
- Katarzyna Andraszek
- Department of Animal Genetics and Horse Breeding, Institute of Bioengineering and Animal Breeding, Siedlce University of Natural Sciences and Humanities, Prusa 14, Poland
| | - Magdalena Gryzińska
- Department of Biological Basis of Animal Production, University of Life Sciences, Lublin, Poland, Akademicka 13 St, 20-950 Lublin, Poland
| | - Agata Danielewicz
- Department of Animal Genetics and Horse Breeding, Institute of Bioengineering and Animal Breeding, Siedlce University of Natural Sciences and Humanities, Prusa 14, Poland
| | - Justyna Batkowska
- Department of Biological Basis of Animal Production, University of Life Sciences, Lublin, Poland, Akademicka 13 St, 20-950 Lublin, Poland
| | - Elżbieta Smalec
- Department of Animal Genetics and Horse Breeding, Institute of Bioengineering and Animal Breeding, Siedlce University of Natural Sciences and Humanities, Prusa 14, Poland
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26
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Nepomuceno-Mejía T, Lara-Martínez R, Hernández R, Segura-Valdez MDL, Jiménez-García LF. Nucleologenesis in Trypanosoma cruzi. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2016; 22:621-629. [PMID: 27126372 DOI: 10.1017/s1431927616000623] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Nucleolar assembly is a cellular event that requires the synthesis and processing of ribosomal RNA, in addition to the participation of pre-nucleolar bodies (PNBs) at the end of mitosis. In mammals and plants, nucleolar biogenesis has been described in detail, but in unicellular eukaryotes it is a poorly understood process. In this study, we used light and electron microscopy cytochemical techniques to investigate the distribution of nucleolar components in the pathway of nucleolus rebuilding during closed cell division in epimastigotes of Trypanosoma cruzi, the etiologic agent of American trypanosomiasis. Silver impregnation specific for nucleolar organizer regions and an ethylenediaminetetraacetic acid regressive procedure to preferentially stain ribonucleoprotein revealed the conservation and dispersion of nucleolar material throughout the nucleoplasm during cell division. Furthermore, at the end of mitosis, the argyrophilic proteins were concentrated in the nucleolar organizer region. Unexpectedly, accumulation of nucleolar material in the form of PNBs was not visualized. We suggest that formation of the nucleolus in epimastigotes of T. cruzi occurs by a process that does not require the concentration of nucleolar material within intermediate nuclear bodies such as mammalian and plant PNBs.
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Affiliation(s)
- Tomás Nepomuceno-Mejía
- 1Laboratory of Electron Microscopy, Faculty of Science,National Autonomous University of Mexico,México Cd. Mx. 04510,México
| | - Reyna Lara-Martínez
- 1Laboratory of Electron Microscopy, Faculty of Science,National Autonomous University of Mexico,México Cd. Mx. 04510,México
| | - Roberto Hernández
- 2Department of Molecular Biology and Biotechnology,Biomedical Research Institute,National Autonomous University of Mexico,México Cd. Mx. 04510,México
| | - María de Lourdes Segura-Valdez
- 1Laboratory of Electron Microscopy, Faculty of Science,National Autonomous University of Mexico,México Cd. Mx. 04510,México
| | - Luis F Jiménez-García
- 1Laboratory of Electron Microscopy, Faculty of Science,National Autonomous University of Mexico,México Cd. Mx. 04510,México
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27
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Koné MC, Fleurot R, Chebrout M, Debey P, Beaujean N, Bonnet-Garnier A. Three-Dimensional Distribution of UBF and Nopp140 in Relationship to Ribosomal DNA Transcription During Mouse Preimplantation Development. Biol Reprod 2016; 94:95. [PMID: 26984997 DOI: 10.1095/biolreprod.115.136366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 03/08/2016] [Indexed: 12/31/2022] Open
Abstract
The nucleolus is a dynamic nuclear compartment that is mostly involved in ribosome subunit biogenesis; however, it may also play a role in many other biological processes, such as stress response and the cell cycle. Mainly using electron microscopy, several studies have tried to decipher how active nucleoli are set up during early development in mice. In this study, we analyzed nucleologenesis during mouse early embryonic development using 3D-immunofluorescent detection of UBF and Nopp140, two proteins associated with different nucleolar compartments. UBF is a transcription factor that helps maintain the euchromatic state of ribosomal genes; Nopp140 is a phosphoprotein that has been implicated in pre-rRNA processing. First, using detailed image analyses and the in situ proximity ligation assay technique, we demonstrate that UBF and Nopp140 dynamic redistribution between the two-cell and blastocyst stages (time of implantation) is correlated with morphological and structural modifications that occur in embryonic nucleolar compartments. Our results also support the hypothesis that nucleoli develop at the periphery of nucleolar precursor bodies. Finally, we show that the RNA polymerase I inhibitor CX-5461: 1) disrupts transcriptional activity, 2) alters preimplantation development, and 3) leads to a complete reorganization of UBF and Nopp140 distribution. Altogether, our results underscore that highly dynamic changes are occurring in the nucleoli of embryos and confirm a close link between ribosomal gene transcription and nucleologenesis during the early stages of development.
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Affiliation(s)
| | - Renaud Fleurot
- UMR BDR, INRA, ENVA, Université Paris Saclay, Jouy en Josas, France
| | - Martine Chebrout
- UMR BDR, INRA, ENVA, Université Paris Saclay, Jouy en Josas, France
| | - Pascale Debey
- Sorbonne-Universités, MNHN, CNRS, INSERM, Structure et instabilité des génomes, Paris, France
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28
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Kalashnikova AA, Rogge RA, Hansen JC. Linker histone H1 and protein-protein interactions. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1859:455-61. [PMID: 26455956 PMCID: PMC4775371 DOI: 10.1016/j.bbagrm.2015.10.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 09/21/2015] [Accepted: 10/05/2015] [Indexed: 01/11/2023]
Abstract
Linker histones H1 are ubiquitous chromatin proteins that play important roles in chromatin compaction, transcription regulation, nucleosome spacing and chromosome spacing. H1 function in DNA and chromatin structure stabilization is well studied and established. The current paradigm of linker histone mode of function considers all other cellular roles of linker histones to be a consequence from H1 chromatin compaction and repression. Here we review the multiple processes regulated by linker histones and the emerging importance of protein interactions in H1 functioning. We propose a new paradigm which explains the multi functionality of linker histones through linker histones protein interactions as a way to directly regulate recruitment of proteins to chromatin.
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Affiliation(s)
- Anna A Kalashnikova
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Ryan A Rogge
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | - Jeffrey C Hansen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA.
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29
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Michalak K, Maciak S, Kim YB, Santopietro G, Oh JH, Kang L, Garner HR, Michalak P. Nucleolar dominance and maternal control of 45S rDNA expression. Proc Biol Sci 2015; 282:20152201. [PMID: 26645200 PMCID: PMC4685780 DOI: 10.1098/rspb.2015.2201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/10/2015] [Indexed: 12/17/2022] Open
Abstract
Using a system of interspecies hybrids, trihybrids, and recombinants with varying proportions of genomes from three distinct Xenopus species, we provide evidence for de novo epigenetic silencing of paternal 45 S ribosomal ribonucleic acid (rRNA) genes and their species-dependent expression dominance that escapes transcriptional inactivation after homologous recombination. The same pattern of imprinting is maintained in the offspring from mothers being genetic males (ZZ) sex-reversed to females, indicating that maternal control of ribosomal deoxyribonucleic acid (rDNA) expression is not sex-chromosome linked. Nucleolar dominance (nucleolus underdevelopment) in Xenopus hybrids appears to be associated with a major non-Mendelian reduction in the number of 45 S rDNA gene copies rather than a specific pattern of their expression. The loss of rRNA gene copies in F1 hybrids was non-random with respect to the parental species, with the transcriptionally dominant variant preferentially removed from hybrid zygotes. This dramatic disruption in the structure and function of 45 S rDNA impacts transcriptome patterns of small nucleolar RNAs and messenger RNAs, with genes from the ribosome and oxidative stress pathways being among the most affected. Unorthodoxies of rDNA inheritance and expression may be interpreted as hallmarks of genetic conflicts between parental genomes, as well as defensive epigenetic mechanisms employed to restore genome integrity.
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Affiliation(s)
- Katarzyna Michalak
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Sebastian Maciak
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061, USA Institute of Biology, University of Bialystok, PL-15-245, Poland
| | - Young Bun Kim
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Jung Hun Oh
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Lin Kang
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061, USA
| | - Harold R Garner
- The Edward Via College of Osteopathic Medicine, Blacksburg, VA 24060, USA
| | - Pawel Michalak
- Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, VA 24061, USA
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30
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Bailly A, Perrin A, Bou Malhab LJ, Pion E, Larance M, Nagala M, Smith P, O'Donohue MF, Gleizes PE, Zomerdijk J, Lamond AI, Xirodimas DP. The NEDD8 inhibitor MLN4924 increases the size of the nucleolus and activates p53 through the ribosomal-Mdm2 pathway. Oncogene 2015; 35:415-26. [PMID: 25867069 DOI: 10.1038/onc.2015.104] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/10/2015] [Accepted: 03/03/2015] [Indexed: 12/19/2022]
Abstract
The ubiquitin-like molecule NEDD8 is essential for viability, growth and development, and is a potential target for therapeutic intervention. We found that the small molecule inhibitor of NEDDylation, MLN4924, alters the morphology and increases the surface size of the nucleolus in human and germline cells of Caenorhabditis elegans in the absence of nucleolar fragmentation. SILAC proteomics and monitoring of rRNA production, processing and ribosome profiling shows that MLN4924 changes the composition of the nucleolar proteome but does not inhibit RNA Pol I transcription. Further analysis demonstrates that MLN4924 activates the p53 tumour suppressor through the RPL11/RPL5-Mdm2 pathway, with characteristics of nucleolar stress. The study identifies the nucleolus as a target of inhibitors of NEDDylation and provides a mechanism for p53 activation upon NEDD8 inhibition. It also indicates that targeting the nucleolar proteome without affecting nucleolar transcription initiates the required signalling events for the control of cell cycle regulators.
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Affiliation(s)
- A Bailly
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - A Perrin
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - L J Bou Malhab
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - E Pion
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
| | - M Larance
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - M Nagala
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - P Smith
- Millennium Pharmaceuticals Inc., Cambridge, MA, USA
| | - M-F O'Donohue
- Laboratoire de Biologie Moléculaire Eucaryote, UMR CNRS 5099, Bâtiment IBCG, Toulouse, France
| | - P-E Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, UMR CNRS 5099, Bâtiment IBCG, Toulouse, France
| | - J Zomerdijk
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - A I Lamond
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, Scotland/UK
| | - D P Xirodimas
- Centre de Recherche de Biochimie Macromoléculaire-UMR 5237, CNRS, Montpellier, France
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31
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Pérez-García C, Rouxel J, Akcha F. Development of a comet-FISH assay for the detection of DNA damage in hemocytes of Crassostrea gigas. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 161:189-195. [PMID: 25710447 DOI: 10.1016/j.aquatox.2015.01.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 01/14/2015] [Accepted: 01/25/2015] [Indexed: 06/04/2023]
Abstract
In this work, the DNA-damaging effect of hydrogen peroxide on the structural integrity of nucleolar organizer regions (NORs) was studied for the first time by comet-FISH in the Pacific oyster Crassostrea gigas. Global DNA damage was assessed in hemocytes using an alkaline version of the comet assay. Next, NOR sensitivity was analyzed by mapping major rDNA repeat unit by fluorescence in situ hybridization (FISH) on the same comet slides. Exposure of hemocytes to 100 μM of hydrogen peroxide induced a significant increase in both DNA damage and number of FISH-signals of major ribosomal genes versus the control. Moreover, a significant positive correlation was shown between DNA damage as measured by the comet assay (percentage of DNA in comet tail) and the number of signals present in comet tails. This study demonstrates the potential value of the comet-FISH assay for the study of DNA damage induced by genotoxicant exposure of target genes. It offers a perspective for better understanding the impact of genotoxicity on animal physiology and fitness.
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Affiliation(s)
- C Pérez-García
- IFREMER, Department of Biogeochemistry and Ecotoxicology, Laboratory of Ecotoxicology, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France.
| | - J Rouxel
- IFREMER, Department of Biogeochemistry and Ecotoxicology, Laboratory of Ecotoxicology, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France
| | - F Akcha
- IFREMER, Department of Biogeochemistry and Ecotoxicology, Laboratory of Ecotoxicology, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France.
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32
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Ehm P, Nalaskowski MM, Wundenberg T, Jücker M. The tumor suppressor SHIP1 colocalizes in nucleolar cavities with p53 and components of PML nuclear bodies. Nucleus 2015; 6:154-64. [PMID: 25723258 DOI: 10.1080/19491034.2015.1022701] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The inositol 5-phosphatase SHIP1 is a negative regulator of signaling processes in haematopoietic cells. By converting PI(3,4,5)P3 to PtdIns(3,4)P2 at the plasma membrane, SHIP1 modifies PI3-kinase mediated signaling. We have recently demonstrated that SHIP1 is a nucleo-cytoplasmic shuttling protein and SHIP1 nuclear puncta partially colocalize with FLASH, a component of nuclear bodies. In this study, we demonstrate that endogenous SHIP1 localizes to intranucleolar regions of both normal and leukemic haematopoietic cells. In addition, we report that ectopically expressed SHIP1 accumulates in nucleolar cavities and colocalizes with the tumor suppressor protein p53 and components of PML nuclear bodies (e.g. SP100, SUMO-1 and CK2). Moreover, SHIP1 also colocalizes in nucleolar cavities with components of the ubiquitin-proteasome pathway. By using confocal microscopy data, we generated 3D-models revealing the enormous extent of the SHIP1 aggresomes in the nucleolus. Furthermore, treatment of cells with the proteasome inhibitor MG132 causes an enlargement of nucleolar SHIP1 containing structures. Unexpectedly, this accumulation can be partially prevented by treatment with the inhibitor of nuclear protein export Leptomycin B. In recent years, several proteins aggregating in nucleolar cavities were shown to be key factors of neurodegenerative diseases and cancerogenesis. Our findings support current relevance of nuclear localized SHIP1.
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Key Words
- DFC, dense fibrillar component
- DIC, Differential interference contrast
- EGFP, enhanced green fluorescent protein
- FC, fibrillar center
- GC, granular component
- LMB, leptomycin B
- MG132
- NES, nuclear export signal
- PBMC, Peripheral Blood Mononuclear Cell
- PML bodies
- PML, Promyelocytic Leukemia
- PtdIns(3, 4)P2, phosphatidylinositol-(3, 4)-bisphosphate
- PtdIns(3, 4, 5)P3, phosphatidylinositol-(3, 4, 5)-trisphosphate
- RNA pol, RNA polymerase
- SHIP1
- SHIP1, src homology 2 domain-containing inositol phosphatase 1
- UPP, ubiquitin-proteasome pathway.
- aggresome
- cancer
- leptomycin B
- nucleolar cavities
- nucleus
- p53
- ubiquitin proteasome pathway
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Affiliation(s)
- Patrick Ehm
- a Institute of Biochemistry and Signal Transduction ; University Medical Center Hamburg-Eppendorf ; Hamburg , Germany
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Wang H, Luo X, You W, Dong Y, Ke C. Cytogenetic analysis and chromosomal characteristics of the polymorphic 18S rDNA of Haliotis discus hannai from Fujian, China. PLoS One 2015; 10:e0113816. [PMID: 25699679 PMCID: PMC4336138 DOI: 10.1371/journal.pone.0113816] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/31/2014] [Indexed: 11/27/2022] Open
Abstract
We report on novel chromosomal characteristics of Haliotis discus hannai from a breeding population at Fujian, China. The karyotypes of H. discus hannai we obtained from an abalone farm include a common type 2n = 36 = 10M + 8SM (82%) and two rare types 2n = 36 = 11M + 7SM (14%) and 2n = 36 = 10M + 7SM + 1ST (4%). The results of silver staining showed that the NORs of H. discus hannai were usually located terminally on the long arms of chromosome pairs 14 and 17, NORs were also sometimes located terminally on the short arms of other chromosomes, either metacentric or submetacentric pairs. The number of Ag-nucleoli ranged from 2 to 8, and the mean number was 3.61 ± 0.93. Among the scored interphase cells, 41% had 3 detectable nucleoli and 37% had 4 nucleoli. The 18S rDNA FISH result is the first report of the location of 18S rDNA genes in H. discus hannai. The 18S rDNA locations were highly polymorphic in this species. Copies of the gene were observed in the terminal of long or/and short arms of submetacentric or/and metacentric chromosomes. Using FISH with probe for vertebrate-like telomeric sequences (CCCTAA)3 displayed positive green FITC signals at telomere regions of all analyzed chromosome types. We found about 7% of chromosomes had breaks in prophase. A special form of nucleolus not previously described from H. discus hannai was observed in some interphase cells. It consists of many small silver-stained nucleoli gathered together to form a larger nucleolus and may correspond to prenucleolar bodies.
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Affiliation(s)
- Haishan Wang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
- Colleges of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Xuan Luo
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
- Colleges of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Weiwei You
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
- Colleges of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Yunwei Dong
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
- Colleges of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Caihuan Ke
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China
- Colleges of Ocean and Earth Sciences, Xiamen University, Xiamen, China
- * E-mail:
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34
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Proteomic characterization of the nucleolar linker histone H1 interaction network. J Mol Biol 2015; 427:2056-71. [PMID: 25584861 DOI: 10.1016/j.jmb.2015.01.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/03/2014] [Accepted: 01/05/2015] [Indexed: 01/25/2023]
Abstract
To investigate the relationship between linker histone H1 and protein-protein interactions in the nucleolus, we used biochemical and proteomics approaches to characterize nucleoli purified from cultured human and mouse cells. Mass spectrometry identified 175 proteins in human T cell nucleolar extracts that bound to Sepharose-immobilized H1 in vitro. Gene ontology analysis found significant enrichment for H1 binding proteins with functions related to nucleolar chromatin structure and RNA polymerase I transcription regulation, rRNA processing, and mRNA splicing. Consistent with the affinity binding results, H1 existed in large (400 to >650kDa) macromolecular complexes in human T cell nucleolar extracts. To complement the biochemical experiments, we investigated the effects of in vivo H1 depletion on protein content and structural integrity of the nucleolus using the H1 triple isoform knockout (H1ΔTKO) mouse embryonic stem cell (mESC) model system. Proteomic profiling of purified wild-type mESC nucleoli identified a total of 613 proteins, only ~60% of which were detected in the H1 mutant nucleoli. Within the affected group, spectral counting analysis quantitated 135 specific nucleolar proteins whose levels were significantly altered in H1ΔTKO mESC. Importantly, the functions of the affected proteins in mESC closely overlapped with those of the human T cell nucleolar H1 binding proteins. Immunofluorescence microscopy of intact H1ΔTKO mESC demonstrated both a loss of nucleolar RNA content and altered nucleolar morphology resulting from in vivo H1 depletion. We conclude that H1 organizes and maintains an extensive protein-protein interaction network in the nucleolus required for nucleolar structure and integrity.
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35
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Lemaître C, Soutoglou E. DSB (Im)mobility and DNA repair compartmentalization in mammalian cells. J Mol Biol 2014; 427:652-8. [PMID: 25463437 DOI: 10.1016/j.jmb.2014.11.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Chromosomal translocations are considered as causal in approximately 20% of cancers. Therefore, understanding their mechanisms of formation is crucial in the prevention of carcinogenesis. The first step of translocation formation is the concomitant occurrence of double-strand DNA breaks (DSBs) in two different chromosomes. DSBs can be repaired by different repair mechanisms, including error-free homologous recombination (HR), potentially error-prone non-homologous end joining (NHEJ) and the highly mutagenic alternative end joining (alt-EJ) pathways. Regulation of DNA repair pathway choice is crucial to avoid genomic instability. In yeast, DSBs are mobile and can scan the entire nucleus to be repaired in specialized DNA repair centers or if they are persistent, in order to associate with the nuclear pores or the nuclear envelope where they can be repaired by specialized repair pathways. DSB mobility is limited in mammals; therefore, raising the question of whether the position at which a DSB occurs influences its repair. Here, we review the recent literature addressing this question. We first present the reports describing the extent of DSB mobility in mammalian cells. In a second part, we discuss the consequences of non-random gene positioning on chromosomal translocations formation. In the third part, we discuss the mobility of heterochromatic DSBs in light of our recent data on DSB repair at the nuclear lamina, and finally, we show that DSB repair compartmentalization at the nuclear periphery is conserved from yeast to mammals, further pointing to a role for gene positioning in the outcome of DSB repair. When regarded as a whole, the different studies reviewed here demonstrate the importance of nuclear architecture on DSB repair and reveal gene positioning as an important parameter in the study of tumorigenesis.
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Affiliation(s)
- Charlène Lemaître
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, CEDEX, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Centre National de Recherche Scientifique, UMR7104, Illkirch, France; Université de Strasbourg, 67404, Illkirch, CEDEX, France
| | - Evi Soutoglou
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, CEDEX, France; Institut National de la Santé et de la Recherche Médicale, U964, Illkirch, France; Centre National de Recherche Scientifique, UMR7104, Illkirch, France; Université de Strasbourg, 67404, Illkirch, CEDEX, France.
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36
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Park H, Han SS, Sako Y, Pack CG. Dynamic and unique nucleolar microenvironment revealed by fluorescence correlation spectroscopy. FASEB J 2014; 29:837-48. [PMID: 25404711 DOI: 10.1096/fj.14-254110] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Organization and functions of the nucleolus is maintained by mobilities and interactions of nucleolar factors. Because the nucleolus is a densely packed structure, molecular crowding effects determined by the molecular concentrations and mobilities in the nucleolus should also be important for regulating nucleolar organization and functions. However, such molecular property of nucleolar organization is not fully understood. To understand the biophysical property of nucleolar organization, the diffusional behaviors of inert green fluorescent protein (GFP) oligomers with or without nuclear localization signals (NLSs) were analyzed under various conditions by fluorescence correlation spectroscopy. Our result demonstrates that the mobility of GFPs inside the nucleolus and the nucleoplasm can be represented by single free diffusion under normal conditions, even though the mobility in the nucleolus is considerably slower than that in the chromatin region. Moreover, the free diffusion of GFPs is found to be significantly size- and NLS-dependent only in the nucleolus. Interestingly, the mobility in the nucleolus is highly sensitive to ATP depletion, as well as actinomycin D (ActD) treatment. In contrast, the ultra-structure of the nucleolus was not significantly changed by ATP depletion but was changed by ActD treatment. These results suggest that the nucleolus behaves similarly to an open aqueous-phase medium with an increased molecular crowding effect that depends on both energy and transcription.
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Affiliation(s)
- Hweon Park
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Sung-Sik Han
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Yasushi Sako
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Chan-Gi Pack
- *Department of Life Sciences, Korea University, Seoul, Republic of Korea; Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama, Japan; and Asan Institute for Life Sciences, University of Ulsan, College of Medicine, Asan Medical Center, Seoul, Republic of Korea
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37
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Stępiński D. Functional ultrastructure of the plant nucleolus. PROTOPLASMA 2014; 251:1285-306. [PMID: 24756369 PMCID: PMC4209244 DOI: 10.1007/s00709-014-0648-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 04/08/2014] [Indexed: 05/23/2023]
Abstract
Nucleoli are nuclear domains present in almost all eukaryotic cells. They not only specialize in the production of ribosomal subunits but also play roles in many fundamental cellular activities. Concerning ribosome biosynthesis, particular stages of this process, i.e., ribosomal DNA transcription, primary RNA transcript processing, and ribosome assembly proceed in precisely defined nucleolar subdomains. Although eukaryotic nucleoli are conservative in respect of their main function, clear morphological differences between these structures can be noticed between individual kingdoms. In most cases, a plant nucleolus shows well-ordered structure in which four main ultrastructural components can be distinguished: fibrillar centers, dense fibrillar component, granular component, and nucleolar vacuoles. Nucleolar chromatin is an additional crucial structural component of this organelle. Nucleolonema, although it is not always an unequivocally distinguished nucleolar domain, has often been described as a well-grounded morphological element, especially of plant nucleoli. The ratios and morphology of particular subcompartments of a nucleolus can change depending on its metabolic activity which in turn is correlated with the physiological state of a cell, cell type, cell cycle phase, as well as with environmental influence. Precise attribution of functions to particular nucleolar subregions in the process of ribosome biosynthesis is now possible using various approaches. The presented description of plant nucleolar morphology summarizes previous knowledge regarding the function of nucleoli as well as of their particular subdomains not only in the course of ribosome biosynthesis.
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Affiliation(s)
- Dariusz Stępiński
- Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236, Łódź, Poland,
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38
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Muro E, Gébrane-Younès J, Jobart-Malfait A, Louvet E, Roussel P, Hernandez-Verdun D. The traffic of proteins between nucleolar organizer regions and prenucleolar bodies governs the assembly of the nucleolus at exit of mitosis. Nucleus 2014. [DOI: 10.4161/nucl.11334] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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39
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Woods E, Courtney J, Scholz D, Hall WW, Gautier VW. Tracking protein dynamics with photoconvertible Dendra2 on spinning disk confocal systems. J Microsc 2014; 256:197-207. [PMID: 25186063 DOI: 10.1111/jmi.12172] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 07/31/2014] [Indexed: 01/25/2023]
Abstract
Understanding the dynamic properties of cellular proteins in live cells and in real time is essential to delineate their function. In this context, we introduce the Fluorescence Recovery After Photobleaching-Photoactivation unit (Andor) combined with the Nikon Eclipse Ti E Spinning Disk (Andor) confocal microscope as an advantageous and robust platform to exploit the properties of the Dendra2 photoconvertible fluorescent protein (Evrogen) and analyse protein subcellular trafficking in living cells. A major advantage of the spinning disk confocal is the rapid acquisition speed, enabling high temporal resolution of cellular processes. Furthermore, photoconversion and imaging are less invasive on the spinning disk confocal as the cell exposition to illumination power is reduced, thereby minimizing photobleaching and increasing cell viability. We have tested this commercially available platform using experimental settings adapted to track the migration of fast trafficking proteins such as UBC9, Fibrillarin and have successfully characterized their differential motion between subnuclear structures. We describe here step-by-step procedures, with emphasis on cellular imaging parameters, to successfully perform the dynamic imaging and photoconversion of Dendra2-fused proteins at high spatial and temporal resolutions necessary to characterize the trafficking pathways of proteins.
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Affiliation(s)
- Elena Woods
- Centre for Research in Infectious Diseases, School of Medicine and Biomedical Science, University College Dublin (UCD), Dublin, Ireland
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40
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Song C, Takagi M, Park J, Xu R, Gallagher-Jones M, Imamoto N, Ishikawa T. Analytic 3D imaging of mammalian nucleus at nanoscale using coherent x-rays and optical fluorescence microscopy. Biophys J 2014; 107:1074-1081. [PMID: 25185543 PMCID: PMC4156684 DOI: 10.1016/j.bpj.2014.07.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/10/2014] [Accepted: 07/15/2014] [Indexed: 11/19/2022] Open
Abstract
Despite the notable progress that has been made with nano-bio imaging probes, quantitative nanoscale imaging of multistructured specimens such as mammalian cells remains challenging due to their inherent structural complexity. Here, we successfully performed three-dimensional (3D) imaging of mammalian nuclei by combining coherent x-ray diffraction microscopy, explicitly visualizing nuclear substructures at several tens of nanometer resolution, and optical fluorescence microscopy, cross confirming the substructures with immunostaining. This demonstrates the successful application of coherent x-rays to obtain the 3D ultrastructure of mammalian nuclei and establishes a solid route to nanoscale imaging of complex specimens.
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Affiliation(s)
| | | | | | - Rui Xu
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan; Department of Physics and Astronomy, University of California, Los Angeles, California
| | - Marcus Gallagher-Jones
- RIKEN SPring-8 Center, Sayo, Hyogo, Japan; Institute of Integrative Biology, University of Liverpool, Liverpool, UK
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41
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Bočkor VV, Barišić D, Horvat T, Maglica Ž, Vojta A, Zoldoš V. Inhibition of DNA methylation alters chromatin organization, nuclear positioning and activity of 45S rDNA loci in cycling cells of Q. robur. PLoS One 2014; 9:e103954. [PMID: 25093501 PMCID: PMC4122370 DOI: 10.1371/journal.pone.0103954] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/03/2014] [Indexed: 12/04/2022] Open
Abstract
Around 2200 copies of genes encoding ribosomal RNA (rRNA) in pedunculate oak, Quercus robur, are organized into two rDNA loci, the major (NOR-1) and the minor (NOR-2) locus. We present the first cytogenetic evidence indicating that the NOR-1 represents the active nucleolar organizer responsible for rRNA synthesis, while the NOR-2 probably stays transcriptionally silent and does not participate in the formation of the nucleolus in Q. robur, which is a situation resembling the well-known phenomenon of nucleolar dominance. rDNA chromatin topology analyses in cycling root tip cells by light and electron microscopy revealed the minor locus to be highly condensed and located away from the nucleolus, while the major locus was consistently associated with the nucleolus and often exhibited different levels of condensation. In addition, silver precipitation was confined exclusively to the NOR-1 locus. Also, NOR-2 was highly methylated at cytosines and rDNA chromatin was marked with histone modifications characteristic for repressive state. After treatment of the root cells with the methylation inhibitor 5-aza-2′-deoxycytidine, we observed an increase in the total level of rRNA transcripts and a decrease in DNA methylation level at the NOR-2 locus. Also, NOR-2 sites relocalized with respect to the nuclear periphery/nucleolus, however, the relocation did not affect the contribution of this locus to nucleolar formation, nor did it affect rDNA chromatin decondensation, strongly suggesting that NOR-2 has lost the function of rRNA synthesis and nucleolar organization.
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Affiliation(s)
- Vedrana Vičić Bočkor
- Faculty of Science, University of Zagreb, Department of Molecular Biology, Zagreb, Croatia
| | - Darko Barišić
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Tomislav Horvat
- Faculty of Science, University of Zagreb, Department of Molecular Biology, Zagreb, Croatia
| | - Željka Maglica
- Ecole Polytechnique Fédéral de Lausanne, Lausanne, Switzerland
| | - Aleksandar Vojta
- Faculty of Science, University of Zagreb, Department of Molecular Biology, Zagreb, Croatia
| | - Vlatka Zoldoš
- Faculty of Science, University of Zagreb, Department of Molecular Biology, Zagreb, Croatia
- * E-mail:
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42
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Mahboubi H, Stochaj U. Nucleoli and Stress Granules: Connecting Distant Relatives. Traffic 2014; 15:1179-93. [DOI: 10.1111/tra.12191] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 06/30/2014] [Accepted: 06/30/2014] [Indexed: 12/19/2022]
Affiliation(s)
- Hicham Mahboubi
- Department of Physiology; McGill University; 3655 Promenade Sir William Osler Montreal Quebec H3G 1Y6 Canada
| | - Ursula Stochaj
- Department of Physiology; McGill University; 3655 Promenade Sir William Osler Montreal Quebec H3G 1Y6 Canada
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43
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Colis L, Ernst G, Sanders S, Liu H, Sirajuddin P, Peltonen K, DePasquale M, Barrow JC, Laiho M. Design, synthesis, and structure-activity relationships of pyridoquinazolinecarboxamides as RNA polymerase I inhibitors. J Med Chem 2014; 57:4950-61. [PMID: 24847734 PMCID: PMC4059246 DOI: 10.1021/jm5004842] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
![]()
RNA polymerase I (Pol I) is a dedicated
polymerase that transcribes
the 45S ribosomal (r) RNA precursor. The 45S rRNA precursor is subsequently
processed into the mature 5.8S, 18S, and 28S rRNAs and assembled into
ribosomes in the nucleolus. Pol I activity is commonly deregulated
in human cancers. On the basis of the discovery of lead molecule BMH-21,
a series of pyridoquinazolinecarboxamides have been evaluated
as inhibitors of Pol I and activators of the destruction of RPA194,
the Pol I large catalytic subunit protein. Structure–activity
relationships in assays of nucleolar stress and cell viability demonstrate
key pharmacophores and their physicochemical properties required for
potent activation of Pol I stress and cytotoxicity. This work identifies
a set of bioactive compounds that potently cause RPA194 degradation
that function in a tightly constrained chemical space. This work has
yielded novel derivatives that contribute to the development of Pol
I inhibitory cancer therapeutic strategies.
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Affiliation(s)
- Laureen Colis
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine , 1550 Orleans Street, Baltimore, Maryland 21287, United States
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44
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Small RNA expression and deep sequencing analyses of the nucleolus reveal the presence of nucleolus-associated microRNAs. FEBS Open Bio 2014; 4:441-9. [PMID: 24918059 PMCID: PMC4050192 DOI: 10.1016/j.fob.2014.04.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 04/04/2014] [Accepted: 04/24/2014] [Indexed: 12/04/2022] Open
Abstract
miRNA expression arrays and RNA Seq were employed for unbiased spatial analyses of miRNAs. Small RNomics of subcellular compartments revealed the presence of miRNAs in the nucleolus. Several miRNAs were detected at low abundance in cancer cell nucleoli. The nucleolar abundance of miR-31 was dependent on CRM1 export factor.
Micro RNAs (miRNA) are non-coding RNAs expressed in the cytoplasm as their mature, 21–22-nucleotide short forms. More recently, mature miRNAs have also been detected in the nucleus, raising the possibility that their spatial distribution may be more complex than anticipated. Here we undertook comprehensive systematic analyses of miRNA distribution in several subcellular compartments of human cancer cells. In particular, we focused on the potential presence of miRNAs in the nucleolus, which contains an abundance of small non-coding RNAs. We employed two miRNA expression array platforms and small RNA deep sequencing of small RNAs isolated from cells, nuclei, cytoplasm and the nucleoli. We developed an assay to compare RNAs of isolated nucleoli before and after denaturation and used Northern hybridization to verify the presence of miRNAs in the subcellular compartments. Consistently, we found more than 10 miRNAs associated with the nucleolar preparations. Several miRNAs had greater relative abundance in the nucleolus compared to the other compartments. The nucleolar presence of miRNAs was independent of Dicer and the main activity of the nucleolus, RNA polymerase I transcription, but was dependent on CRM1 previously associated with nucleolar trafficking of small nucleolar RNAs. These results highlight the complexity of miRNA spatial arrangement and regulation.
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45
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Yan S, Zhang Q, Li Y, Huang Y, Zhao L, Tan J, He S, Li L. Comparison of chromatin epigenetic modification patterns among root meristem, elongation and maturation zones in maize (Zea mays L.). Cytogenet Genome Res 2014; 143:179-88. [PMID: 24731999 DOI: 10.1159/000361003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Plant roots mainly consist of division, elongation and maturation regions. Histone modifications of chromatin play a vital role in plant cell growth and differentiation. However, there has been no systematic attempt to investigate the distribution patterns of histone modifications in the different plant root zones. In this study, histone H3 acetylation (H3K9ac), histone H4 acetylation (H4K5ac), and histone H3 methylation (H3K4me2, H3K4me3, H3K9me1, H3K9me2, and H3K27me2) levels and distribution patterns were examined in the root meristem, elongation and maturation zones of maize primary roots. Overall, the cells of the maturation zone displayed the highest level of multiple histone modifications. The lowest level of histone modification was detected in the root meristem. H3K9ac was enriched in the euchromatin and nucleoli of most nuclei from the elongation and maturation zones. The nucleoli of more than 60% of cells from all root regions were labeled by H4K5ac. In only a small proportion of cells (less than 7%), knobs showed H4K5ac signals. H3K4me2 and H3K4me3 were specifically detected in euchromatin. H3K9me1, H3K9me2 and H3K27me2 labeled heterochromatin and euchromatin in all the root tissues analyzed. Over 30% of elongation and maturation cells exhibited H3K9me1 signals around knobs, approximately 5% of maturation cells showed signals of H3K9me2 around knobs, and H3K27me2 was stained weakly in approximately 95% of maturation cells in knobs. Analysis of the genomic patterns of histone modifications across functionally distinct regions of maize roots reveals a root zone-specific chromatin distribution.
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Affiliation(s)
- Shihan Yan
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, PR China
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46
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Louvet E, Yoshida A, Kumeta M, Takeyasu K. Probing the stiffness of isolated nucleoli by atomic force microscopy. Histochem Cell Biol 2014; 141:365-81. [PMID: 24297448 DOI: 10.1007/s00418-013-1167-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2013] [Indexed: 11/24/2022]
Abstract
In eukaryotic cells, ribosome biogenesis occurs in the nucleolus, a membraneless nuclear compartment. Noticeably, the nucleolus is also involved in several nuclear functions, such as cell cycle regulation, non-ribosomal ribonucleoprotein complex assembly, aggresome formation and some virus assembly. The most intriguing question about the nucleolus is how such dynamics processes can occur in such a compact compartment. We hypothesized that its structure may be rather flexible. To investigate this, we used atomic force microscopy (AFM) on isolated nucleoli. Surface topography imaging revealed the beaded structure of the nucleolar surface. With the AFM's ability to measure forces, we were able to determine the stiffness of isolated nucleoli. We could establish that the nucleolar stiffness varies upon drastic morphological changes induced by transcription and proteasome inhibition. Furthermore, upon ribosomal proteins and LaminB1 knockdowns, the nucleolar stiffness was increased. This led us to propose a model where the nucleolus has steady-state stiffness dependent on ribosome biogenesis activity and requires LaminB1 for its flexibility.
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Affiliation(s)
- Emilie Louvet
- Graduate School of Biostudies, Kyoto University, Kyoto, 606-8501, Japan,
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47
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Vlatković N, Boyd MT, Rubbi CP. Nucleolar control of p53: a cellular Achilles' heel and a target for cancer therapy. Cell Mol Life Sci 2014; 71:771-91. [PMID: 23685903 PMCID: PMC11113510 DOI: 10.1007/s00018-013-1361-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 04/07/2013] [Accepted: 04/30/2013] [Indexed: 02/07/2023]
Abstract
Nucleoli perform a crucial cell function, ribosome biogenesis, and of critical relevance to the subject of this review, they are also extremely sensitive to cellular stresses, which can cause loss of function and/or associated structural disruption. In recent years, we have learned that cells take advantage of this stress sensitivity of nucleoli, using them as stress sensors. One major protein regulated by this role of nucleoli is the tumor suppressor p53, which is activated in response to diverse cellular injuries in order to exert its onco-protective effects. Here we discuss a model of nucleolar regulation of p53, which proposes that key steps in the promotion of p53 degradation by the ubiquitin ligase MDM2 occur in nucleoli, thus providing an explanation for the observed link between nucleolar disruption and p53 stability. We review current evidence for this compartmentalization in p53 homeostasis and highlight current limitations of the model. Interestingly, a number of current chemotherapeutic agents capable of inducing a p53 response are likely to do so by targeting nucleolar functions and these compounds may serve to inform further improved therapeutic targeting of nucleoli.
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Affiliation(s)
- Nikolina Vlatković
- Cancer Research Centre, University of Liverpool, 200 London Rd, Liverpool, L3 9TA UK
| | - Mark T. Boyd
- Cancer Research Centre, University of Liverpool, 200 London Rd, Liverpool, L3 9TA UK
| | - Carlos P. Rubbi
- Cancer Research Centre, University of Liverpool, 200 London Rd, Liverpool, L3 9TA UK
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48
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Sampaio TR, Pires LB, da Rosa R, Dias AL. Activity patterns of nucleolar organizer region during spermatogenesis of different curimatid species (Characiformes: Curimatidae). Genome 2014; 57:119-24. [DOI: 10.1139/gen-2013-0161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nucleolus is an important nuclear structure where transcription of ribosomal DNA (rDNA) takes place. During mitotic division, the nucleolus passes through different processes that inactivate rDNA transcription; in meiosis, its reassembly takes place during telophase II. The objective of this study was to identify the activity patterns and localization of nucleolar organizer regions (NORs) during meiotic division in fish species of the family Curimatidae. For this analysis, the meiotic division in five curimatid species was studied using silver nitrate impregnation, fluorescent in situ hybridization (FISH), and base-specific fluorochrome staining. Silver nitrate staining indicated the presence of a nucleolus in interphase nuclei, one chromosome pair in the spermatogonial metaphases, and one bivalent at the pachytene stage. No Ag-NORs were identified for cells at the diplotene, diakinesis, metaphase I, or metaphase II stages; however, FISH confirmed the presence of Ag-NORs in the nuclei, in spermatogonia, and at the pachytene phase. FISH identified this region during the other stages of meiosis, as did fluorochrome CMA3 staining, which revealed fluorescent marks corresponding to NORs during all stages of meiosis analyzed. The gene activity and localization of this ribosomal sequence during the different stages involved will also be discussed.
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Affiliation(s)
- Tatiane R. Sampaio
- Centro de Ciências Biológicas, Departamento de Biologia Geral, Universidade Estadual de Londrina, 86051-970, Londrina, Paraná, Brazil
| | - Larissa B. Pires
- Centro de Ciências Biológicas, Departamento de Biologia Geral, Universidade Estadual de Londrina, 86051-970, Londrina, Paraná, Brazil
| | - Renata da Rosa
- Centro de Ciências Biológicas, Departamento de Biologia Geral, Universidade Estadual de Londrina, 86051-970, Londrina, Paraná, Brazil
| | - Ana Lúcia Dias
- Centro de Ciências Biológicas, Departamento de Biologia Geral, Universidade Estadual de Londrina, 86051-970, Londrina, Paraná, Brazil
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49
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Peltonen K, Colis L, Liu H, Trivedi R, Moubarek MS, Moore HM, Bai B, Rudek MA, Bieberich CJ, Laiho M. A targeting modality for destruction of RNA polymerase I that possesses anticancer activity. Cancer Cell 2014; 25:77-90. [PMID: 24434211 PMCID: PMC3930145 DOI: 10.1016/j.ccr.2013.12.009] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/03/2013] [Accepted: 12/16/2013] [Indexed: 01/07/2023]
Abstract
We define the activity and mechanisms of action of a small molecule lead compound for cancer targeting. We show that the compound, BMH-21, has wide and potent antitumorigenic activity across NCI60 cancer cell lines and represses tumor growth in vivo. BMH-21 binds GC-rich sequences, which are present at a high frequency in ribosomal DNA genes, and potently and rapidly represses RNA polymerase I (Pol I) transcription. Strikingly, we find that BMH-21 causes proteasome-dependent destruction of RPA194, the large catalytic subunit protein of Pol I holocomplex, and this correlates with cancer cell killing. Our results show that Pol I activity is under proteasome-mediated control, which reveals an unexpected therapeutic opportunity.
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Affiliation(s)
- Karita Peltonen
- Molecular Cancer Biology Program and Centre for Drug Research, University of Helsinki, Helsinki 00014, Finland
| | - Laureen Colis
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Hester Liu
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Rishi Trivedi
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Michael S Moubarek
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Henna M Moore
- Molecular Cancer Biology Program and Centre for Drug Research, University of Helsinki, Helsinki 00014, Finland
| | - Baoyan Bai
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Michelle A Rudek
- Department of Oncology and The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Charles J Bieberich
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Marikki Laiho
- Molecular Cancer Biology Program and Centre for Drug Research, University of Helsinki, Helsinki 00014, Finland; Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Oncology and The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
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50
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Phase separation as a possible means of nuclear compartmentalization. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 307:109-49. [PMID: 24380594 DOI: 10.1016/b978-0-12-800046-5.00005-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The nucleus is perhaps the most familiar organelle within eukaryotic cells, serving as a compartment to house the genetic material. The nuclear volume is subdivided into a variety of functional and dynamic nuclear bodies not separated from the nucleoplasm by membranes. It has been hypothesized that aqueous phase separation brought about by macromolecular crowding may be in part responsible for these intranuclear compartments. This chapter discusses macromolecular solution chemistry with regard to several common types of phase separation in polymer solutions as well as to recent evidence that suggests that cytoplasmic and nuclear bodies may exist as liquid phases. We then examine the functional significance of phase separation and how it may serve as a means of compartmentalizing various nuclear activities, and describe recent studies that have used simple model systems to generate coexisting aqueous phase compartments, concentrate molecules within them, and perform localized biochemical reactions.
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