1
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King MR, Ruff KM, Lin AZ, Pant A, Farag M, Lalmansingh JM, Wu T, Fossat MJ, Ouyang W, Lew MD, Lundberg E, Vahey MD, Pappu RV. Macromolecular condensation organizes nucleolar sub-phases to set up a pH gradient. Cell 2024; 187:1889-1906.e24. [PMID: 38503281 DOI: 10.1016/j.cell.2024.02.029] [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: 07/18/2023] [Revised: 01/02/2024] [Accepted: 02/22/2024] [Indexed: 03/21/2024]
Abstract
Nucleoli are multicomponent condensates defined by coexisting sub-phases. We identified distinct intrinsically disordered regions (IDRs), including acidic (D/E) tracts and K-blocks interspersed by E-rich regions, as defining features of nucleolar proteins. We show that the localization preferences of nucleolar proteins are determined by their IDRs and the types of RNA or DNA binding domains they encompass. In vitro reconstitutions and studies in cells showed how condensation, which combines binding and complex coacervation of nucleolar components, contributes to nucleolar organization. D/E tracts of nucleolar proteins contribute to lowering the pH of co-condensates formed with nucleolar RNAs in vitro. In cells, this sets up a pH gradient between nucleoli and the nucleoplasm. By contrast, juxta-nucleolar bodies, which have different macromolecular compositions, featuring protein IDRs with very different charge profiles, have pH values that are equivalent to or higher than the nucleoplasm. Our findings show that distinct compositional specificities generate distinct physicochemical properties for condensates.
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Affiliation(s)
- Matthew R King
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Kiersten M Ruff
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Andrew Z Lin
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Avnika Pant
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Mina Farag
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Jared M Lalmansingh
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Tingting Wu
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Department of Electrical and Systems Engineering, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Martin J Fossat
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Wei Ouyang
- Department of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA; Department of Pathology, School of Medicine, Stanford University, Stanford, CA, USA; Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Matthew D Lew
- Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Department of Electrical and Systems Engineering, James F. McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Emma Lundberg
- Department of Bioengineering, Schools of Engineering and Medicine, Stanford University, Stanford, CA, USA; Department of Pathology, School of Medicine, Stanford University, Stanford, CA, USA; Science for Life Laboratory, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Michael D Vahey
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Rohit V Pappu
- Department of Biomedical Engineering, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA; Center for Biomolecular Condensates, James McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, USA.
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2
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Theophanous A, Christodoulou A, Mattheou C, Sibai DS, Moss T, Santama N. Transcription factor UBF depletion in mouse cells results in downregulation of both downstream and upstream elements of the rRNA transcription network. J Biol Chem 2023; 299:105203. [PMID: 37660911 PMCID: PMC10558777 DOI: 10.1016/j.jbc.2023.105203] [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: 03/17/2023] [Revised: 08/20/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Transcription/processing of the ribosomal RNA (rRNA) precursor, as part of ribosome biosynthesis, is intensively studied and characterized in eukaryotic cells. Here, we constructed shRNA-based mouse cell lines partially silenced for the Upstream Binding Factor UBF, the master regulator of rRNA transcription and organizer of open rDNA chromatin. Full Ubf silencing in vivo is not viable, and these new tools allow further characterization of rRNA transcription and its coordination with cellular signaling. shUBF cells display cell cycle G1 delay and reduced 47S rRNA precursor and 28S rRNA at baseline and serum-challenged conditions. Growth-related mTOR signaling is downregulated with the fractions of active phospho-S6 Kinase and pEIF4E translation initiation factor reduced, similar to phosphorylated cell cycle regulator retinoblastoma, pRB, positive regulator of UBF availability/rRNA transcription. Additionally, we find transcription-competent pUBF (Ser484) severely restricted and its interacting initiation factor RRN3 reduced and responsive to extracellular cues. Furthermore, fractional UBF occupancy on the rDNA unit is decreased in shUBF, and expression of major factors involved in different aspects of rRNA transcription is severely downregulated by UBF depletion. Finally, we observe reduced RNA Pol1 occupancy over rDNA promoter sequences and identified unexpected regulation of RNA Pol1 expression, relative to serum availability and under UBF silencing, suggesting that regulation of rRNA transcription may not be restricted to modulation of Pol1 promoter binding/elongation rate. Overall, this work reveals that UBF depletion has a critical downstream and upstream impact on the whole network orchestrating rRNA transcription in mammalian cells.
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Affiliation(s)
- Andria Theophanous
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus
| | | | | | - Dany S Sibai
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Quebec, Canada; Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec, Canada
| | - Tom Moss
- Laboratory of Growth and Development, St-Patrick Research Group in Basic Oncology, Cancer Division of the Quebec University Hospital Research Centre, Quebec, Canada; Department of Molecular Biology, Medical Biochemistry and Pathology, Faculty of Medicine, Laval University, Quebec, Canada
| | - Niovi Santama
- Department of Biological Sciences, University of Cyprus, Nicosia, Cyprus.
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3
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Zhai F, Wang J, Luo X, Ye M, Jin X. Roles of NOLC1 in cancers and viral infection. J Cancer Res Clin Oncol 2023; 149:10593-10608. [PMID: 37296317 DOI: 10.1007/s00432-023-04934-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 05/23/2023] [Indexed: 06/12/2023]
Abstract
BACKGROUND The nucleolus is considered the center of metabolic control and an important organelle for the biogenesis of ribosomal RNA (rRNA). Nucleolar and coiled-body phosphoprotein 1(NOLC1), which was originally identified as a nuclear localization signal-binding protein is a nucleolar protein responsible for nucleolus construction and rRNA synthesis, as well as chaperone shuttling between the nucleolus and cytoplasm. NOLC1 plays an important role in a variety of cellular life activities, including ribosome biosynthesis, DNA replication, transcription regulation, RNA processing, cell cycle regulation, apoptosis, and cell regeneration. PURPOSE In this review, we introduce the structure and function of NOLC1. Then we elaborate its upstream post-translational modification and downstream regulation. Meanwhile, we describe its role in cancer development and viral infection which provide a direction for future clinical applications. METHODS The relevant literatures from PubMed have been reviewed for this article. CONCLUSION NOLC1 plays an important role in the progression of multiple cancers and viral infection. In-depth study of NOLC1 provides a new perspective for accurate diagnosis of patients and selection of therapeutic targets.
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Affiliation(s)
- Fengguang Zhai
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China
| | - Jie Wang
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China
| | - Xia Luo
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China
| | - Meng Ye
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China.
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China.
| | - Xiaofeng Jin
- Department of Biochemistry and Molecular Biology, Zhejiang Key Laboratory of Pathophysiology, Health Science Center, Ningbo University, Ningbo, 315211, China.
- The Affiliated First Hospital, Ningbo University, Ningbo, 315020, China.
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4
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Dörner K, Ruggeri C, Zemp I, Kutay U. Ribosome biogenesis factors-from names to functions. EMBO J 2023; 42:e112699. [PMID: 36762427 PMCID: PMC10068337 DOI: 10.15252/embj.2022112699] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/13/2022] [Accepted: 01/19/2023] [Indexed: 02/11/2023] Open
Abstract
The assembly of ribosomal subunits is a highly orchestrated process that involves a huge cohort of accessory factors. Most eukaryotic ribosome biogenesis factors were first identified by genetic screens and proteomic approaches of pre-ribosomal particles in Saccharomyces cerevisiae. Later, research on human ribosome synthesis not only demonstrated that the requirement for many of these factors is conserved in evolution, but also revealed the involvement of additional players, reflecting a more complex assembly pathway in mammalian cells. Yet, it remained a challenge for the field to assign a function to many of the identified factors and to reveal their molecular mode of action. Over the past decade, structural, biochemical, and cellular studies have largely filled this gap in knowledge and led to a detailed understanding of the molecular role that many of the players have during the stepwise process of ribosome maturation. Such detailed knowledge of the function of ribosome biogenesis factors will be key to further understand and better treat diseases linked to disturbed ribosome assembly, including ribosomopathies, as well as different types of cancer.
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Affiliation(s)
- Kerstin Dörner
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.,Molecular Life Sciences Ph.D. Program, Zurich, Switzerland
| | - Chiara Ruggeri
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland.,RNA Biology Ph.D. Program, Zurich, Switzerland
| | - Ivo Zemp
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Ulrike Kutay
- Department of Biology, Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
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5
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Li J, Wang H, Zhu J, Yang Q, Luan Y, Shi L, Molina-Mora JA, Zheng Y. De novo assembly of a chromosome-level reference genome of the ornamental butterfly Sericinus montelus based on nanopore sequencing and Hi-C analysis. Front Genet 2023; 14:1107353. [PMID: 36968580 PMCID: PMC10030965 DOI: 10.3389/fgene.2023.1107353] [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: 11/24/2022] [Accepted: 02/27/2023] [Indexed: 03/29/2023] Open
Abstract
Sericinus montelus (Lepidoptera, Papilionidae, Parnassiinae) is a high-value ornamental swallowtail butterfly species widely distributed in Northern and Central China, Japan, Korea, and Russia. The larval stage of this species feeds exclusively on Aristolochia plants. The Aristolochia species is well known for its high levels of aristolochic acids (AAs), which have been found to be carcinogenic for numerous animals. The swallowtail butterfly is among the few that can feed on these toxic host plants. However, the genetic adaptation of S. montelus to confer new abilities for AA tolerance has not yet been well explored, largely due to the limited genomic resources of this species. This study aimed to present a chromosome-level reference genome for S. montelus using the Oxford Nanopore long-read sequencing, Illumina short-read sequencing, and Hi-C technology. The final assembly was composed of 581.44 Mb with an expected genome size of 619.27 Mb. Further, 99.98% of the bases could be anchored onto 30 chromosomes. The N50 of contigs and scaffolds was 5.74 and 19.12 Mb, respectively. Approximately 48.86% of the assembled genome was suggested to be repeat elements, and 13,720 protein-coding genes were predicted in the current assembly. The phylogenetic analysis indicated that S. montelus diverged from the common ancestor of swallowtails about 58.57-80.46 million years ago. Compared with related species, S. montelus showed a significant expansion of P450 gene family members, and positive selections on eloa, heatr1, and aph1a resulted in the AA tolerance for S. montelus larva. The de novo assembly of a high-quality reference genome for S. montelus provided a fundamental genomic tool for future research on evolution, genome genetics, and toxicology of the swallowtail butterflies.
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Affiliation(s)
- Jingjing Li
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
- Grandomics Biosciences Institute, Wuhan, China
| | - Haiyan Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
| | | | - Qi Yang
- Grandomics Biosciences Institute, Wuhan, China
| | - Yang Luan
- Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Leming Shi
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
- Cancer Institute, Shanghai Cancer Center, Fudan University, Shanghai, China
| | - José Arturo Molina-Mora
- Centro de Investigación en Enfermedades Tropicales, Facultad de Microbiología, Universidad de Costa Rica, San José, Costa Rica
- *Correspondence: José Arturo Molina-Mora, ; Yuanting Zheng,
| | - Yuanting Zheng
- State Key Laboratory of Genetic Engineering, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
- *Correspondence: José Arturo Molina-Mora, ; Yuanting Zheng,
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6
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McCool MA, Bryant CJ, Huang H, Ogawa LM, Farley-Barnes KI, Sondalle SB, Abriola L, Surovtseva YV, Baserga SJ. Human nucleolar protein 7 (NOL7) is required for early pre-rRNA accumulation and pre-18S rRNA processing. RNA Biol 2023; 20:257-271. [PMID: 37246770 PMCID: PMC10228412 DOI: 10.1080/15476286.2023.2217392] [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] [Accepted: 05/19/2023] [Indexed: 05/30/2023] Open
Abstract
The main components of the essential cellular process of eukaryotic ribosome biogenesis are highly conserved from yeast to humans. Among these, the U3 Associated Proteins (UTPs) are a small subunit processome subcomplex that coordinate the first two steps of ribosome biogenesis in transcription and pre-18S processing. While we have identified the human counterparts of most of the yeast Utps, the homologs of yeast Utp9 and Bud21 (Utp16) have remained elusive. In this study, we find that NOL7 is the likely ortholog of Bud21. Previously described as a tumour suppressor through regulation of antiangiogenic transcripts, we now show that NOL7 is required for early pre-rRNA accumulation and pre-18S rRNA processing in human cells. These roles lead to decreased protein synthesis and induction of the nucleolar stress response upon NOL7 depletion. Beyond Bud21's nonessential role in yeast, we establish human NOL7 as an essential UTP that is necessary to maintain both early pre-rRNA levels and processing.
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Affiliation(s)
- Mason A. McCool
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Carson J. Bryant
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Hannah Huang
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Lisa M. Ogawa
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Katherine I. Farley-Barnes
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Samuel B. Sondalle
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Laura Abriola
- Yale Center for Molecular Discovery, Yale University, West Haven, CT, USA
| | | | - Susan J. Baserga
- Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
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7
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McCool MA, Buhagiar AF, Bryant CJ, Ogawa LM, Abriola L, Surovtseva YV, Baserga SJ. Human pre-60S assembly factors link rRNA transcription to pre-rRNA processing. RNA (NEW YORK, N.Y.) 2022; 29:rna.079149.122. [PMID: 36323459 PMCID: PMC9808572 DOI: 10.1261/rna.079149.122] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
In eukaryotes, the nucleolus is the site of ribosome biosynthesis, an essential process in all cells. While human ribosome assembly is largely evolutionarily conserved, many of the regulatory details underlying its control and function have not yet been well-defined. The nucleolar protein RSL24D1 was originally identified as a factor important for 60S ribosomal subunit biogenesis. In addition, the PeBoW (BOP1-PES1-WDR12) complex has been well-defined as required for pre-28S rRNA processing and cell proliferation. In this study, we show that RSL24D1 depletion impairs both pre-ribosomal RNA (pre-rRNA) transcription and mature 28S rRNA production, leading to decreased protein synthesis and p53 stabilization in human cells. Surprisingly, each of the PeBoW complex members is also required for pre-rRNA transcription. We demonstrate that RSL24D1 and WDR12 co-immunoprecipitate with the RNA polymerase I subunit, RPA194, and regulate its steady state levels. These results uncover the dual role of RSL24D1 and the PeBoW complex in multiple steps of ribosome biogenesis, and provide evidence implicating large ribosomal subunit biogenesis factors in pre-rRNA transcription control.
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8
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Oborská-Oplová M, Gerhardy S, Panse VG. Orchestrating ribosomal RNA folding during ribosome assembly. Bioessays 2022; 44:e2200066. [PMID: 35751450 DOI: 10.1002/bies.202200066] [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: 03/29/2022] [Revised: 05/30/2022] [Accepted: 06/13/2022] [Indexed: 11/08/2022]
Abstract
Construction of the eukaryotic ribosome is a complex process in which a nascent ribosomal RNA (rRNA) emerging from RNA Polymerase I hierarchically folds into a native three-dimensional structure. Modular assembly of individual RNA domains through interactions with ribosomal proteins and a myriad of assembly factors permit efficient disentanglement of the error-prone RNA folding process. Following these dynamic events, long-range tertiary interactions are orchestrated to compact rRNA. A combination of genetic, biochemical, and structural studies is now providing clues into how a nascent rRNA is transformed into a functional ribosome with high precision. With this essay, we aim to draw attention to the poorly understood process of establishing correct RNA tertiary contacts during ribosome formation.
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Affiliation(s)
| | - Stefan Gerhardy
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Vikram Govind Panse
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.,Faculty of Science, University of Zurich, Zurich, Switzerland
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9
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Dörner K, Badertscher L, Horváth B, Hollandi R, Molnár C, Fuhrer T, Meier R, Sárazová M, van den Heuvel J, Zamboni N, Horvath P, Kutay U. Genome-wide RNAi screen identifies novel players in human 60S subunit biogenesis including key enzymes of polyamine metabolism. Nucleic Acids Res 2022; 50:2872-2888. [PMID: 35150276 PMCID: PMC8934630 DOI: 10.1093/nar/gkac072] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 01/18/2022] [Accepted: 01/25/2022] [Indexed: 12/19/2022] Open
Abstract
Ribosome assembly is an essential process that is linked to human congenital diseases and tumorigenesis. While great progress has been made in deciphering mechanisms governing ribosome biogenesis in eukaryotes, an inventory of factors that support ribosome synthesis in human cells is still missing, in particular regarding the maturation of the large 60S subunit. Here, we performed a genome-wide RNAi screen using an imaging-based, single cell assay to unravel the cellular machinery promoting 60S subunit assembly in human cells. Our screen identified a group of 310 high confidence factors. These highlight the conservation of the process across eukaryotes and reveal the intricate connectivity of 60S subunit maturation with other key cellular processes, including splicing, translation, protein degradation, chromatin organization and transcription. Intriguingly, we also identified a cluster of hits comprising metabolic enzymes of the polyamine synthesis pathway. We demonstrate that polyamines, which have long been used as buffer additives to support ribosome assembly in vitro, are required for 60S maturation in living cells. Perturbation of polyamine metabolism results in early defects in 60S but not 40S subunit maturation. Collectively, our data reveal a novel function for polyamines in living cells and provide a rich source for future studies on ribosome synthesis.
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Affiliation(s)
- Kerstin Dörner
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
- Molecular Life Sciences Ph.D. Program, 8057 Zurich, Switzerland
| | - Lukas Badertscher
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
- Molecular Life Sciences Ph.D. Program, 8057 Zurich, Switzerland
| | - Bianka Horváth
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
- Molecular Life Sciences Ph.D. Program, 8057 Zurich, Switzerland
| | - Réka Hollandi
- Synthetic and Systems Biology Unit, Biological Research Center, 6726 Szeged, Hungary
| | - Csaba Molnár
- Synthetic and Systems Biology Unit, Biological Research Center, 6726 Szeged, Hungary
| | - Tobias Fuhrer
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Roger Meier
- ScopeM, ETH Zürich, 8093 Zürich, Switzerland
| | - Marie Sárazová
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Jasmin van den Heuvel
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Nicola Zamboni
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Peter Horvath
- Synthetic and Systems Biology Unit, Biological Research Center, 6726 Szeged, Hungary
- Institute for Molecular Medicine Finland, University of Helsinki, 00014 Helsinki, Finland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
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10
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Moudry P, Chroma K, Bursac S, Volarevic S, Bartek J. RNA-interference screen for p53 regulators unveils a role of WDR75 in ribosome biogenesis. Cell Death Differ 2022; 29:687-696. [PMID: 34611297 PMCID: PMC8901908 DOI: 10.1038/s41418-021-00882-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 01/05/2023] Open
Abstract
Ribosome biogenesis is an essential, energy demanding process whose deregulation has been implicated in cancer, aging, and neurodegeneration. Ribosome biogenesis is therefore under surveillance of pathways including the p53 tumor suppressor. Here, we first performed a high-content siRNA-based screen of 175 human ribosome biogenesis factors, searching for impact on p53. Knock-down of 4 and 35 of these proteins in U2OS cells reduced and increased p53 abundance, respectively, including p53 accumulation after depletion of BYSL, DDX56, and WDR75, the effects of which were validated in several models. Using complementary approaches including subcellular fractionation, we demonstrate that endogenous human WDR75 is a nucleolar protein and immunofluorescence analysis of ectopic GFP-tagged WDR75 shows relocation to nucleolar caps under chemically induced nucleolar stress, along with several canonical nucleolar proteins. Mechanistically, we show that WDR75 is required for pre-rRNA transcription, through supporting the maintenance of physiological levels of RPA194, a key subunit of the RNA polymerase I. Furthermore, WDR75 depletion activated the RPL5/RPL11-dependent p53 stabilization checkpoint, ultimately leading to impaired proliferation and cellular senescence. These findings reveal a crucial positive role of WDR75 in ribosome biogenesis and provide a resource of human ribosomal factors the malfunction of which affects p53.
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Affiliation(s)
- Pavel Moudry
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic.
| | - Katarina Chroma
- grid.10979.360000 0001 1245 3953Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic
| | - Sladana Bursac
- grid.22939.330000 0001 2236 1630Department of Molecular Medicine and Biotechnology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Sinisa Volarevic
- grid.22939.330000 0001 2236 1630Department of Molecular Medicine and Biotechnology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jiri Bartek
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, Olomouc, Czech Republic. .,Genome Integrity, Danish Cancer Society Research Center, Copenhagen, Denmark. .,Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden.
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11
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Bryant CJ, McCool MA, Abriola L, Surovtseva YV, Baserga SJ. A high-throughput assay for directly monitoring nucleolar rRNA biogenesis. Open Biol 2022; 12:210305. [PMID: 35078352 PMCID: PMC8790372 DOI: 10.1098/rsob.210305] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Studies of the regulation of nucleolar function are critical for ascertaining clearer insights into the basic biological underpinnings of ribosome biogenesis (RB), and for future development of therapeutics to treat cancer and ribosomopathies. A number of high-throughput primary assays based on morphological alterations of the nucleolus can indirectly identify hits affecting RB. However, there is a need for a more direct high-throughput assay for a nucleolar function to further evaluate hits. Previous reports have monitored nucleolar rRNA biogenesis using 5-ethynyl uridine (5-EU) in low-throughput. We report a miniaturized, high-throughput 5-EU assay that enables specific calculation of nucleolar rRNA biogenesis inhibition, based on co-staining of the nucleolar protein fibrillarin (FBL). The assay uses two siRNA controls: a negative non-targeting siRNA control and a positive siRNA control targeting RNA Polymerase 1 (RNAP1; POLR1A), and specifically quantifies median 5-EU signal within nucleoli. Maximum nuclear 5-EU signal can also be used to monitor the effects of putative small-molecule inhibitors of RNAP1, like BMH-21, or other treatment conditions that cause FBL dispersion. We validate the 5-EU assay on 68 predominately nucleolar hits from a high-throughput primary screen, showing that 58/68 hits significantly inhibit nucleolar rRNA biogenesis. Our new method establishes direct quantification of nucleolar function in high-throughput, facilitating closer study of RB in health and disease.
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Affiliation(s)
- Carson J. Bryant
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Mason A. McCool
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - Laura Abriola
- Yale Center for Molecular Discovery, Yale University, West Haven, CT, USA
| | | | - Susan J. Baserga
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, 333 Cedar Street, New Haven, CT, USA,Department of Genetics, Yale School of Medicine, New Haven, CT, USA,Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT, USA
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12
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Schächner C, Merkl PE, Pilsl M, Schwank K, Hergert K, Kruse S, Milkereit P, Tschochner H, Griesenbeck J. Establishment and Maintenance of Open Ribosomal RNA Gene Chromatin States in Eukaryotes. Methods Mol Biol 2022; 2533:25-38. [PMID: 35796980 PMCID: PMC9761505 DOI: 10.1007/978-1-0716-2501-9_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In growing eukaryotic cells, nuclear ribosomal (r)RNA synthesis by RNA polymerase (RNAP) I accounts for the vast majority of cellular transcription. This high output is achieved by the presence of multiple copies of rRNA genes in eukaryotic genomes transcribed at a high rate. In contrast to most of the other transcribed genomic loci, actively transcribed rRNA genes are largely devoid of nucleosomes adapting a characteristic "open" chromatin state, whereas a significant fraction of rRNA genes resides in a transcriptionally inactive nucleosomal "closed" chromatin state. Here, we review our current knowledge about the nature of open rRNA gene chromatin and discuss how this state may be established.
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Affiliation(s)
- Christopher Schächner
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Philipp E Merkl
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
- TUM ForTe, Technische Universität München, Munich, Germany
| | - Michael Pilsl
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Katrin Schwank
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Kristin Hergert
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Sebastian Kruse
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany
| | - Philipp Milkereit
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| | - Herbert Tschochner
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
| | - Joachim Griesenbeck
- Universität Regensburg, Regensburg Center for Biochemistry (RCB), Lehrstuhl Biochemie III, Regensburg, Germany.
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13
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Padilla-Mejia NE, Makarov AA, Barlow LD, Butterfield ER, Field MC. Evolution and diversification of the nuclear envelope. Nucleus 2021; 12:21-41. [PMID: 33435791 PMCID: PMC7889174 DOI: 10.1080/19491034.2021.1874135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells arose ~1.5 billion years ago, with the endomembrane system a central feature, facilitating evolution of intracellular compartments. Endomembranes include the nuclear envelope (NE) dividing the cytoplasm and nucleoplasm. The NE possesses universal features: a double lipid bilayer membrane, nuclear pore complexes (NPCs), and continuity with the endoplasmic reticulum, indicating common evolutionary origin. However, levels of specialization between lineages remains unclear, despite distinct mechanisms underpinning various nuclear activities. Several distinct modes of molecular evolution facilitate organellar diversification and to understand which apply to the NE, we exploited proteomic datasets of purified nuclear envelopes from model systems for comparative analysis. We find enrichment of core nuclear functions amongst the widely conserved proteins to be less numerous than lineage-specific cohorts, but enriched in core nuclear functions. This, together with consideration of additional evidence, suggests that, despite a common origin, the NE has evolved as a highly diverse organelle with significant lineage-specific functionality.
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Affiliation(s)
- Norma E. Padilla-Mejia
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Alexandr A. Makarov
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Lael D. Barlow
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Erin R. Butterfield
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Mark C. Field
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České, Czech Republic
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14
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Zhou H, Wang Y, Wang Q, Li L, Hu Y, Wu Y, Gautam M, Li L. R-loops mediate transcription-associated formation of human rDNA secondary constrictions. J Cell Biochem 2021; 122:1517-1533. [PMID: 34224593 DOI: 10.1002/jcb.30074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 04/28/2021] [Accepted: 06/10/2021] [Indexed: 11/07/2022]
Abstract
The ribosomal gene DNA (rDNA) often forms secondary constrictions in the chromosome; however, the molecular mechanism involved remains poorly understood. Here, we report that occurrence of rDNA constriction was increased in the chromosomes in human cancer cell lines compared with normal cells and that decondensed rDNA was significantly enhanced after partial inhibition of rDNA transcription. rDNA transcription was found during the S phase when replication occurred, and thus, DNA replication inhibitors caused constriction formation through hindering rDNA transcription. Inhibition of ataxia ATR (telangiectasia-mutated and RAD3-related) induced rDNA constriction formation. Replication stress or transcription inhibition increased R-loop formation. Topoisomerase I and RNase H1 suppressed secondary constriction formation. These data demonstrate that transcription stress causes the accumulation of stable R-loops (RNA-DNA hybrid) and subsequent constriction formation in the chromosomes.
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Affiliation(s)
- Hong Zhou
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China.,Department of Physiology, School of Basic medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Yapei Wang
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China.,Department of Gynecology and Obstetrics, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qing Wang
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
| | - Le Li
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yan Hu
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yequn Wu
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
| | - Mayank Gautam
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
| | - Lijia Li
- Department of Genetics, College of Life Sciences, Wuhan University, Wuhan, China
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15
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Kron NS, Fieber LA. Co-expression analysis identifies neuro-inflammation as a driver of sensory neuron aging in Aplysia californica. PLoS One 2021; 16:e0252647. [PMID: 34116561 PMCID: PMC8195618 DOI: 10.1371/journal.pone.0252647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/20/2021] [Indexed: 01/08/2023] Open
Abstract
Aging of the nervous system is typified by depressed metabolism, compromised proteostasis, and increased inflammation that results in cognitive impairment. Differential expression analysis is a popular technique for exploring the molecular underpinnings of neural aging, but technical drawbacks of the methodology often obscure larger expression patterns. Co-expression analysis offers a robust alternative that allows for identification of networks of genes and their putative central regulators. In an effort to expand upon previous work exploring neural aging in the marine model Aplysia californica, we used weighted gene correlation network analysis to identify co-expression networks in a targeted set of aging sensory neurons in these animals. We identified twelve modules, six of which were strongly positively or negatively associated with aging. Kyoto Encyclopedia of Genes analysis and investigation of central module transcripts identified signatures of metabolic impairment, increased reactive oxygen species, compromised proteostasis, disrupted signaling, and increased inflammation. Although modules with immune character were identified, there was no correlation between genes in Aplysia that increased in expression with aging and the orthologous genes in oyster displaying long-term increases in expression after a virus-like challenge. This suggests anti-viral response is not a driver of Aplysia sensory neuron aging.
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Affiliation(s)
- N. S. Kron
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
| | - L. A. Fieber
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, United States of America
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16
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The Ribosomal Gene Loci-The Power behind the Throne. Genes (Basel) 2021; 12:genes12050763. [PMID: 34069807 PMCID: PMC8157237 DOI: 10.3390/genes12050763] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/20/2022] Open
Abstract
Nucleoli form around actively transcribed ribosomal RNA (rRNA) genes (rDNA), and the morphology and location of nucleolus-associated genomic domains (NADs) are linked to the RNA Polymerase I (Pol I) transcription status. The number of rDNA repeats (and the proportion of actively transcribed rRNA genes) is variable between cell types, individuals and disease state. Substantial changes in nucleolar morphology and size accompanied by concomitant changes in the Pol I transcription rate have long been documented during normal cell cycle progression, development and malignant transformation. This demonstrates how dynamic the nucleolar structure can be. Here, we will discuss how the structure of the rDNA loci, the nucleolus and the rate of Pol I transcription are important for dynamic regulation of global gene expression and genome stability, e.g., through the modulation of long-range genomic interactions with the suppressive NAD environment. These observations support an emerging paradigm whereby the rDNA repeats and the nucleolus play a key regulatory role in cellular homeostasis during normal development as well as disease, independent of their role in determining ribosome capacity and cellular growth rates.
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17
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Nakamura A, Kakihara Y, Funayama A, Haga K, Mikami T, Kobayashi D, Yoshida Y, Izumi K, Kobayashi T, Saeki M. HEATR1, a novel interactor of Pontin/Reptin, stabilizes Pontin/Reptin and promotes cell proliferation of oral squamous cell carcinoma. Biochem Biophys Res Commun 2021; 557:294-301. [PMID: 33894417 DOI: 10.1016/j.bbrc.2021.04.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/07/2021] [Indexed: 12/25/2022]
Abstract
Pontin and Reptin are closely related proteins belonging to the AAA+ (ATPases Associated with various cellular Activities) family. They form a hetero-oligomeric complex, Pontin/Reptin, which is involved in protein stability and assembly of the protein complexes as a molecular chaperone. Overexpression of Pontin and Reptin in tumor cells has been reported and is implicated in the development of various cancers. However, the molecular mechanism of Pontin/Reptin function in oral squamous cell carcinoma (OSCC) development remains unclear. Here, we identify HEAT repeat-containing protein 1 (HEATR1) as a novel binding factor of Pontin/Reptin. Functionally, HEATR1 stabilizes Pontin/Reptin and positively regulates OSCC cell proliferation by activating mTOR and pre-rRNA synthesis. We also find that HEATR1 expression is markedly upregulated in tumor region of OSCC tissue. Hence, we propose that HEATR1 is involved in the regulation of mTOR and ribosome biogenesis as a potential protein stabilizer of Pontin/Reptin in OSCC.
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Affiliation(s)
- Akihiko Nakamura
- Division of Reconstructive Surgery for Oral and Maxillofacial Region, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan; Division of Dental Pharmacology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
| | - Yoshito Kakihara
- Division of Dental Pharmacology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan.
| | - Akinori Funayama
- Division of Reconstructive Surgery for Oral and Maxillofacial Region, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
| | - Kenta Haga
- Division of Reconstructive Surgery for Oral and Maxillofacial Region, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
| | - Toshihiko Mikami
- Division of Reconstructive Surgery for Oral and Maxillofacial Region, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
| | - Daiki Kobayashi
- Omics Unit, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan
| | - Yutaka Yoshida
- Department of Structural Pathology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8510, Japan
| | - Kenji Izumi
- Division of Biomimetics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
| | - Tadaharu Kobayashi
- Division of Reconstructive Surgery for Oral and Maxillofacial Region, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
| | - Makio Saeki
- Division of Dental Pharmacology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata, 951-8514, Japan
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18
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Korsholm LM, Gál Z, Nieto B, Quevedo O, Boukoura S, Lund CC, Larsen DH. Recent advances in the nucleolar responses to DNA double-strand breaks. Nucleic Acids Res 2020; 48:9449-9461. [PMID: 32857853 PMCID: PMC7515731 DOI: 10.1093/nar/gkaa713] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/13/2020] [Accepted: 08/26/2020] [Indexed: 12/15/2022] Open
Abstract
DNA damage poses a serious threat to human health and cells therefore continuously monitor and repair DNA lesions across the genome. Ribosomal DNA is a genomic domain that represents a particular challenge due to repetitive sequences, high transcriptional activity and its localization in the nucleolus, where the accessibility of DNA repair factors is limited. Recent discoveries have significantly extended our understanding of how cells respond to DNA double-strand breaks (DSBs) in the nucleolus, and new kinases and multiple down-stream targets have been identified. Restructuring of the nucleolus can occur as a consequence of DSBs and new data point to an active regulation of this process, challenging previous views. Furthermore, new insights into coordination of cell cycle phases and ribosomal DNA repair argue against existing concepts. In addition, the importance of nucleolar-DNA damage response (n-DDR) mechanisms for maintenance of genome stability and the potential of such factors as anti-cancer targets is becoming apparent. This review will provide a detailed discussion of recent findings and their implications for our understanding of the n-DDR. The n-DDR shares features with the DNA damage response (DDR) elsewhere in the genome but is also emerging as an independent response unique to ribosomal DNA and the nucleolus.
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Affiliation(s)
| | | | - Blanca Nieto
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Oliver Quevedo
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Stavroula Boukoura
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
| | - Casper Carstens Lund
- Danish Cancer Society Research Center, Nucleolar Stress and Disease Group, Strandboulevarden 49, 2100 Copenhagen, Denmark
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19
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Fujimura A, Hayashi Y, Kato K, Kogure Y, Kameyama M, Shimamoto H, Daitoku H, Fukamizu A, Hirota T, Kimura K. Identification of a novel nucleolar protein complex required for mitotic chromosome segregation through centromeric accumulation of Aurora B. Nucleic Acids Res 2020; 48:6583-6596. [PMID: 32479628 PMCID: PMC7337965 DOI: 10.1093/nar/gkaa449] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 04/24/2020] [Accepted: 05/15/2020] [Indexed: 12/11/2022] Open
Abstract
The nucleolus is a membrane-less nuclear structure that disassembles when cells undergo mitosis. During mitosis, nucleolar factors are thus released from the nucleolus and dynamically change their subcellular localization; however, their functions remain largely uncharacterised. Here, we found that a nucleolar factor called nucleolar protein 11 (NOL11) forms a protein complex with two tryptophan-aspartic acid (WD) repeat proteins named WD-repeat protein 43 (WDR43) and Cirhin in mitotic cells. This complex, referred to here as the NWC (NOL11-WDR43-Cirhin) complex, exists in nucleoli during interphase and translocates to the periphery of mitotic chromosomes, i.e., perichromosomal regions. During mitotic progression, both the congression of chromosomes to the metaphase plate and sister chromatid cohesion are impaired in the absence of the NWC complex, as it is required for the centromeric enrichment of Aurora B and the associating phosphorylation of histone H3 at threonine 3. These results reveal the characteristics of a novel protein complex consisting of nucleolar proteins, which is required for regulating kinetochores and centromeres to ensure faithful chromosome segregation.
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Affiliation(s)
- Akiko Fujimura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Yuki Hayashi
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Kazashi Kato
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Yuichiro Kogure
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Mutsuro Kameyama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Haruka Shimamoto
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Hiroaki Daitoku
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Akiyoshi Fukamizu
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Toru Hirota
- Cancer Institute of the Japanese Foundation for Cancer Research, Division of Experimental Pathology, 3-8-1 Ariake, Koto-ku, Tokyo 135-8550, Japan
| | - Keiji Kimura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan.,Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
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20
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Zhao J, Zhu Y, Fu Q, Zhu Y, Zhao G. HEATR1 promotes proliferation in gastric cancer in vitro and in vivo. Acta Biochim Biophys Sin (Shanghai) 2020; 52:1030-1039. [PMID: 32634230 DOI: 10.1093/abbs/gmaa077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 10/17/2019] [Accepted: 12/26/2019] [Indexed: 01/01/2023] Open
Abstract
HEAT repeat-containing protein 1 (HEATR1) is related to the progression of several cancers. However, the role of HEATR1 in gastric cancer (GC) remains unknown. In the present study, we aimed to detect the expression of HEATR1 in GC and identify its role. The expressions of HEATR1 in GC tissues were analyzed using The Cancer Genome Atlas database and by western blot analysis and immunohistochemistry. Furthermore, the HEATR1 expressions in GC cell lines MGC-803 and AGS were knocked down by using lentivirus-mediated HEATR1 shRNA. Cell proliferation and apoptosis were detected by CCK-8 and Caspase-Glo® 3/7 assays, respectively. PathScan® Signaling Antibody Array kit and Kyoto Encyclopedia of Genes and Genomes enrichment were used to study the pathways related to HEATR1. The influence of HEATR1 shRNA on the in vivo growth of GC cells was assessed by establishing a nude mouse xenograft model and conducting bioluminescence imaging. Our results showed that HEATR1 was highly expressed in GC tissues. Higher expression of HEATR1 is related to cancer progression and metastasis. Knocking down HEATR1 significantly suppressed the cell proliferation and colony formation and promoted cell apoptosis. The expression levels of phosphorylated p53, p38 MAPK, Chk2, and IKBa in shHEATR1-transfected MGC-803 cells exceeded those in shCtrl-transfected cells. HEATR1 shRNA treatment also significantly inhibited tumor growth in the mouse model. This study suggested that HEATR1 may be an oncogene and a target for GC therapy.
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Affiliation(s)
- Jun Zhao
- Department of Gastrointestinal Surgery, Yijishan Hospital of Wannan Medical College, Wuhu 241000, China
| | - Yiping Zhu
- Department of Gastrointestinal Surgery, Yijishan Hospital of Wannan Medical College, Wuhu 241000, China
| | - Qingsheng Fu
- Department of Gastrointestinal Surgery, Yijishan Hospital of Wannan Medical College, Wuhu 241000, China
| | - Yimei Zhu
- Department of Gastrointestinal Surgery, Yijishan Hospital of Wannan Medical College, Wuhu 241000, China
| | - Guohai Zhao
- Department of Gastrointestinal Surgery, Yijishan Hospital of Wannan Medical College, Wuhu 241000, China
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21
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Vydzhak O, Luke B, Schindler N. Non-coding RNAs at the Eukaryotic rDNA Locus: RNA-DNA Hybrids and Beyond. J Mol Biol 2020; 432:4287-4304. [PMID: 32446803 DOI: 10.1016/j.jmb.2020.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/12/2022]
Abstract
The human ribosomal DNA (rDNA) locus encodes a variety of long non-coding RNAs (lncRNAs). Among them, the canonical ribosomal RNAs that are the catalytic components of the ribosomes, as well as regulatory lncRNAs including promoter-associated RNAs (pRNA), stress-induced promoter and pre-rRNA antisense RNAs (PAPAS), and different intergenic spacer derived lncRNA species (IGSRNA). In addition, externally encoded lncRNAs are imported into the nucleolus, which orchestrate the complex regulation of the nucleolar state in normal and stress conditions via a plethora of molecular mechanisms. This review focuses on the triplex and R-loop formation aspects of lncRNAs at the rDNA locus in yeast and human cells. We discuss the protein players that regulate R-loops at rDNA and how their misregulation contributes to DNA damage and disease. Furthermore, we speculate how DNA lesions such as rNMPs or 8-oxo-dG might affect RNA-DNA hybrid formation. The transcription of lncRNA from rDNA has been observed in yeast, plants, flies, worms, mouse and human cells. This evolutionary conservation highlights the importance of lncRNAs in rDNA function and maintenance.
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Affiliation(s)
- Olga Vydzhak
- Institute of Molecular Biology (IMB), Johannes Gutenberg-University Mainz, Ackermannweg 4, 55128 Mainz, Germany
| | - Brian Luke
- Institute of Molecular Biology (IMB), Johannes Gutenberg-University Mainz, Ackermannweg 4, 55128 Mainz, Germany; Institute of Developmental Biology and Neurobiology (IDN), Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - Natalie Schindler
- Institute of Developmental Biology and Neurobiology (IDN), Johannes Gutenberg-University Mainz, 55128 Mainz, Germany.
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22
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NORs on human acrocentric chromosome p-arms are active by default and can associate with nucleoli independently of rDNA. Proc Natl Acad Sci U S A 2020; 117:10368-10377. [PMID: 32332163 PMCID: PMC7229746 DOI: 10.1073/pnas.2001812117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
A detailed description of how the genome is organized within the human nucleus is a major research goal. Nucleolar organizer regions (NORs) comprising ribosomal DNA (rDNA) arrays are located on the p-arms of the five human acrocentric chromosomes. Here we characterize the rules of engagement between NORs and nucleoli. We reveal variation in rDNA distribution, with some primary cell lines containing as many as four acrocentrics devoid of rDNA. We establish the default status of NORs as active and show that acrocentric p-arms devoid of rDNA retain nucleolar association potential. Based on our data, we propose that in diploid human cells, all 10 acrocentric chromosomes are nucleolar-associated, with involvement of non-rDNA sequences buffering against variable rDNA distribution. Nucleoli, the sites of ribosome biogenesis and the largest structures in human nuclei, form around nucleolar organizer regions (NORs) comprising ribosomal DNA (rDNA) arrays. NORs are located on the p-arms of the five human acrocentric chromosomes. Defining the rules of engagement between these p-arms and nucleoli takes on added significance as describing the three-dimensional organization of the human genome represents a major research goal. Here we used fluorescent in situ hybridization (FISH) and immuno-FISH on metaphase chromosomes from karyotypically normal primary and hTERT-immortalized human cell lines to catalog NORs in terms of their relative rDNA content and activity status. We demonstrate that a proportion of acrocentric p-arms in cell lines and from normal human donors have no detectable rDNA. Surprisingly, we found that all NORs with detectable rDNA are active, as defined by upstream binding factor loading. We determined the nucleolar association status of all NORs during interphase, and found that nucleolar association of acrocentric p-arms can occur independently of rDNA content, suggesting that sequences elsewhere on these chromosome arms drive nucleolar association. In established cancer lines, we characterize a variety of chromosomal rearrangements involving acrocentric p-arms and observe silent, rDNA-containing NORs that are dissociated from nucleoli. In conclusion, our findings indicate that within human nuclei, positioning of all 10 acrocentric chromosomes is dictated by nucleolar association. Furthermore, these nucleolar associations are buffered against interindividual variation in the distribution of rDNA.
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Izumikawa K, Ishikawa H, Yoshikawa H, Fujiyama S, Watanabe A, Aburatani H, Tachikawa H, Hayano T, Miura Y, Isobe T, Simpson RJ, Li L, Min J, Takahashi N. LYAR potentiates rRNA synthesis by recruiting BRD2/4 and the MYST-type acetyltransferase KAT7 to rDNA. Nucleic Acids Res 2019; 47:10357-10372. [PMID: 31504794 PMCID: PMC6821171 DOI: 10.1093/nar/gkz747] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/22/2019] [Accepted: 08/20/2018] [Indexed: 02/06/2023] Open
Abstract
Activation of ribosomal RNA (rRNA) synthesis is pivotal during cell growth and proliferation, but its aberrant upregulation may promote tumorigenesis. Here, we demonstrate that the candidate oncoprotein, LYAR, enhances ribosomal DNA (rDNA) transcription. Our data reveal that LYAR binds the histone-associated protein BRD2 without involvement of acetyl-lysine-binding bromodomains and recruits BRD2 to the rDNA promoter and transcribed regions via association with upstream binding factor. We show that BRD2 is required for the recruitment of the MYST-type acetyltransferase KAT7 to rDNA loci, resulting in enhanced local acetylation of histone H4. In addition, LYAR binds a complex of BRD4 and KAT7, which is then recruited to rDNA independently of the BRD2-KAT7 complex to accelerate the local acetylation of both H4 and H3. BRD2 also helps recruit BRD4 to rDNA. By contrast, LYAR has no effect on rDNA methylation or the binding of RNA polymerase I subunits to rDNA. These data suggest that LYAR promotes the association of the BRD2-KAT7 and BRD4-KAT7 complexes with transcription-competent rDNA loci but not to transcriptionally silent rDNA loci, thereby increasing rRNA synthesis by altering the local acetylation status of histone H3 and H4.
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Affiliation(s)
- Keiichi Izumikawa
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Hideaki Ishikawa
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Harunori Yoshikawa
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Sally Fujiyama
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Akira Watanabe
- Department of Life Science Frontiers, Center for iPS Cell Research and Application, Kyoto University 53, Shogoin-kawahara-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan
| | - Hiroyuki Aburatani
- Laboratory for System Biology and Medicine, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Hiroyuki Tachikawa
- Department of Applied Life Science, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toshiya Hayano
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu 525-8577, Japan
| | - Yutaka Miura
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Toshiaki Isobe
- Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Richard J Simpson
- Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,La Trobe Institute for Molecular Science (LIMS) LIMS Building 1, Room 412 La Trobe University, Bundoora Victoria 3086, Australia
| | - Li Li
- Structural Genomics Consortium, University of Toronto, 101 College St., Toronto, Ontario M5G 1L7, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jinrong Min
- Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,Structural Genomics Consortium, University of Toronto, 101 College St., Toronto, Ontario M5G 1L7, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nobuhiro Takahashi
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
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24
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Trinh DA, Shirakawa R, Kimura T, Sakata N, Goto K, Horiuchi H. Inhibitor of Growth 4 (ING4) is a positive regulator of rRNA synthesis. Sci Rep 2019; 9:17235. [PMID: 31754246 PMCID: PMC6872537 DOI: 10.1038/s41598-019-53767-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 08/30/2019] [Indexed: 01/29/2023] Open
Abstract
Ribosome biogenesis is essential for maintaining basic cellular activities although its mechanism is not fully understood. Inhibitor of growth 4 (ING4) is a member of ING family while its cellular functions remain controversial. Here, we identified several nucleolar proteins as novel ING4 interacting proteins. ING4 localized in the nucleus with strong accumulation in the nucleolus through its plant homeodomain, which is known to interact with histone trimethylated H3K4, commonly present in the promoter of active genes. ING4 deficient cells exhibited slower proliferation and the alteration in nucleolar structure with reduced rRNA transcription, which was rescued by exogenous expression of GFP-ING4 to the similar levels of wild type cells. In the ING4 deficient cells, histone H3K9 acetylation and the key rRNA transcription factor UBF at the promoter of rDNA were reduced, both of which were also recovered by exogenous GFP-ING4 expression. Thus, ING4 could positively regulate rRNA transcription through modulation of histone modifications at the rDNA promoter.
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Affiliation(s)
- Duc-Anh Trinh
- Department of Oral Cancer Therapeutics, Graduate School of Dentistry, Tohoku University, Sendai, Japan.,Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Ryutaro Shirakawa
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Tomohiro Kimura
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.,Research Center for Molecular Genetics, Institute for Promotion of Medical Science Research, Yamagata University Faculty of Medicine, Yamagata, Yamagata, Japan
| | - Natsumi Sakata
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Kota Goto
- Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Hisanori Horiuchi
- Department of Oral Cancer Therapeutics, Graduate School of Dentistry, Tohoku University, Sendai, Japan. .,Department of Molecular and Cellular Biology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
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25
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Cui K, Liu C, Li X, Zhang Q, Li Y. Comprehensive characterization of the rRNA metabolism-related genes in human cancer. Oncogene 2019; 39:786-800. [PMID: 31548613 DOI: 10.1038/s41388-019-1026-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/10/2019] [Accepted: 09/12/2019] [Indexed: 01/01/2023]
Abstract
Although rRNA metabolism-related genes have been reported to be associated with human cancer, a systematic assessment of rRNA metabolism-related genes across human cancers is lacking. Thus, we performed a Pan-cancer analysis of rRNA metabolism-related genes across 20 human cancers. Here, we examined mRNA expression, mutation, DNA methylation, copy number variation (CNV) and clinical landscape of rRNA metabolism-related genes in more than 8600 patients across 20 human cancers from The Cancer Genome Atlas (TCGA) dataset. Besides, ten independent Gene Expression Omnibus (GEO) datasets, Cancer Cell Line Encyclopedia (CCLE) dataset and Project Achilles dataset were used to verify our study. A landscape of rRNA metabolism-related genes was established across 20 human cancers. The results suggest that rRNA metabolism-related genes are upregulated in multiple cancers, particularly in digestive and respiratory system cancers. Most of the upregulated genes were driven by CNV gain rather than mutation or DNA hypomethylation. We systematically identified CNV-driven rRNA metabolism-related genes with clinical relevance, including EXOSC8. Finally, functional experiments confirmed the oncogenic roles of EXOSC8 in colorectal carcinoma. Our study highlights the important roles of rRNA metabolism-related genes in tumorigenesis as prognostic biomarkers.
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Affiliation(s)
- Kaisa Cui
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Cheng Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Xu Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Qiang Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China.,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China
| | - Youjun Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, 430072, China. .,Medical Research Institute, School of Medicine, Wuhan University, Wuhan, 430071, China.
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26
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Yao RW, Xu G, Wang Y, Shan L, Luan PF, Wang Y, Wu M, Yang LZ, Xing YH, Yang L, Chen LL. Nascent Pre-rRNA Sorting via Phase Separation Drives the Assembly of Dense Fibrillar Components in the Human Nucleolus. Mol Cell 2019; 76:767-783.e11. [PMID: 31540874 DOI: 10.1016/j.molcel.2019.08.014] [Citation(s) in RCA: 163] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 02/04/2019] [Accepted: 08/13/2019] [Indexed: 12/21/2022]
Abstract
Fibrillar centers (FCs) and dense fibrillar components (DFCs) are essential morphologically distinct sub-regions of mammalian cell nucleoli for rDNA transcription and pre-rRNA processing. Here, we report that a human nucleolus consists of several dozen FC/DFC units, each containing 2-3 transcriptionally active rDNAs at the FC/DFC border. Pre-rRNA processing factors, such as fibrillarin (FBL), form 18-24 clusters that further assemble into the DFC surrounding the FC. Mechanistically, the 5' end of nascent 47S pre-rRNA binds co-transcriptionally to the RNA-binding domain of FBL. FBL diffuses to the DFC, where local self-association via its glycine- and arginine-rich (GAR) domain forms phase-separated clusters to immobilize FBL-interacting pre-rRNA, thus promoting directional traffic of nascent pre-rRNA while facilitating pre-rRNA processing and DFC formation. These results unveil FC/DFC ultrastructures in nucleoli and suggest a conceptual framework for considering nascent RNA sorting using multivalent interactions of their binding proteins.
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Affiliation(s)
- Run-Wen Yao
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Guang Xu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Ying Wang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Lin Shan
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Peng-Fei Luan
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Yang Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Man Wu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Liang-Zhong Yang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Yu-Hang Xing
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Li Yang
- CAS Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
| | - Ling-Ling Chen
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China; School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China.
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27
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Sirri V, Grob A, Berthelet J, Jourdan N, Roussel P. Sirtuin 7 promotes 45S pre-rRNA cleavage at site 2 and determines the processing pathway. J Cell Sci 2019; 132:jcs228601. [PMID: 31331964 PMCID: PMC6771141 DOI: 10.1242/jcs.228601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 07/10/2019] [Indexed: 01/06/2023] Open
Abstract
In humans, ribosome biogenesis mainly occurs in nucleoli following two alternative pre-rRNA processing pathways differing in the order in which cleavages take place but not by the sites of cleavage. To uncover the role of the nucleolar NAD+-dependent deacetylase sirtuin 7 in the synthesis of ribosomal subunits, pre-rRNA processing was analyzed after sirtinol-mediated inhibition of sirtuin 7 activity or depletion of sirtuin 7 protein. We thus reveal that sirtuin 7 activity is a critical regulator of processing of 45S, 32S and 30S pre-rRNAs. Sirtuin 7 protein is primarily essential to 45S pre-rRNA cleavage at site 2, which is the first step of processing pathway 2. Furthermore, we demonstrate that sirtuin 7 physically interacts with Nop56 and the GAR domain of fibrillarin, and propose that this could interfere with fibrillarin-dependent cleavage. Sirtuin 7 depletion results in the accumulation of 5' extended forms of 32S pre-rRNA, and also influences the localization of fibrillarin. Thus, we establish a close relationship between sirtuin 7 and fibrillarin, which might determine the processing pathway used for ribosome biogenesis.
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Affiliation(s)
- Valentina Sirri
- Université de Paris, Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR 8251, CNRS, 4 rue Marie-Andrée Lagroua Weill-Hallé, F-75013 Paris, France
| | - Alice Grob
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England, UK
| | - Jérémy Berthelet
- Université de Paris, Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR 8251, CNRS, 4 rue Marie-Andrée Lagroua Weill-Hallé, F-75013 Paris, France
| | - Nathalie Jourdan
- Sorbonne Université, Institut de Biologie Paris-Seine (IBPS), UMR 8256, CNRS, 9 quai St Bernard, F-75005 Paris, France
| | - Pascal Roussel
- Université de Paris, Unité de Biologie Fonctionnelle et Adaptative (BFA), UMR 8251, CNRS, 4 rue Marie-Andrée Lagroua Weill-Hallé, F-75013 Paris, France
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28
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Walker B, Taylor D, Lawrimore J, Hult C, Adalsteinsson D, Bloom K, Forest MG. Transient crosslinking kinetics optimize gene cluster interactions. PLoS Comput Biol 2019; 15:e1007124. [PMID: 31433796 PMCID: PMC6730938 DOI: 10.1371/journal.pcbi.1007124] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/06/2019] [Accepted: 07/18/2019] [Indexed: 02/05/2023] Open
Abstract
Our understanding of how chromosomes structurally organize and dynamically interact has been revolutionized through the lens of long-chain polymer physics. Major protein contributors to chromosome structure and dynamics are condensin and cohesin that stochastically generate loops within and between chains, and entrap proximal strands of sister chromatids. In this paper, we explore the ability of transient, protein-mediated, gene-gene crosslinks to induce clusters of genes, thereby dynamic architecture, within the highly repeated ribosomal DNA that comprises the nucleolus of budding yeast. We implement three approaches: live cell microscopy; computational modeling of the full genome during G1 in budding yeast, exploring four decades of timescales for transient crosslinks between 5kbp domains (genes) in the nucleolus on Chromosome XII; and, temporal network models with automated community (cluster) detection algorithms applied to the full range of 4D modeling datasets. The data analysis tools detect and track gene clusters, their size, number, persistence time, and their plasticity (deformation). Of biological significance, our analysis reveals an optimal mean crosslink lifetime that promotes pairwise and cluster gene interactions through "flexible" clustering. In this state, large gene clusters self-assemble yet frequently interact (merge and separate), marked by gene exchanges between clusters, which in turn maximizes global gene interactions in the nucleolus. This regime stands between two limiting cases each with far less global gene interactions: with shorter crosslink lifetimes, "rigid" clustering emerges with clusters that interact infrequently; with longer crosslink lifetimes, there is a dissolution of clusters. These observations are compared with imaging experiments on a normal yeast strain and two condensin-modified mutant cell strains. We apply the same image analysis pipeline to the experimental and simulated datasets, providing support for the modeling predictions.
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Affiliation(s)
- Benjamin Walker
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Dane Taylor
- Department of Mathematics, University at Buffalo, State University of New York, Buffalo, New York, United States of America
- Computational and Data Enabled Science and Engineering, University at Buffalo, State University of New York, Buffalo, New York, United States of America
| | - Josh Lawrimore
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Caitlin Hult
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - David Adalsteinsson
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - M. Gregory Forest
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Departments of Applied Physical Sciences and Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
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29
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Gallagher JEG. Proteins and RNA sequences required for the transition of the t-Utp complex into the SSU processome. FEMS Yeast Res 2019; 19:5184469. [PMID: 30445532 DOI: 10.1093/femsyr/foy120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 11/12/2018] [Indexed: 12/20/2022] Open
Abstract
Ribosomes are synthesized by large ribonucleoprotein complexes cleaving and properly assembling highly structured rRNAs with ribosomal proteins. Transcription and processing of pre-rRNAs are linked by the transcription-Utp sub-complex (t-Utps), a sub-complex of the small subunit (SSU) processome and prompted the investigations for the requirements of t-Utp formation and transition into the SSU processome. The rDNA promoter, the first 44 nucleotides of the 5΄ETS, and active transcription by pol I were sufficient to recruit the t-Utps to the rDNA. Pol5, accessory factor, dissociated as t-Utps matured into the UtpA complex which permitted later recruitment of the UtpB, U3 snoRNP and the Mpp10 complex into the SSU processome. The t-Utp complex associated with short RNAs 121 and 138 nucleotides long transcribed from the 5΄ETS. These transcripts were not present when pol II transcribed the rDNA or in nondividing cells. Depletion of a t-Utp, but not of other SSU processome components led to decreased levels of the short transcripts. However, ectopic expression of the short transcripts slowed the growth of yeast with impaired rDNA transcription. These results provide insight into how transcription of the rRNA primes the assemble of t-Utp complex with the pre-rRNA into the UtpA complex and the later association of SSU processome components.
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30
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Bohnsack KE, Bohnsack MT. Uncovering the assembly pathway of human ribosomes and its emerging links to disease. EMBO J 2019; 38:e100278. [PMID: 31268599 PMCID: PMC6600647 DOI: 10.15252/embj.2018100278] [Citation(s) in RCA: 136] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/18/2019] [Accepted: 04/26/2019] [Indexed: 12/12/2022] Open
Abstract
The essential cellular process of ribosome biogenesis is at the nexus of various signalling pathways that coordinate protein synthesis with cellular growth and proliferation. The fact that numerous diseases are caused by defects in ribosome assembly underscores the importance of obtaining a detailed understanding of this pathway. Studies in yeast have provided a wealth of information about the fundamental principles of ribosome assembly, and although many features are conserved throughout eukaryotes, the larger size of human (pre-)ribosomes, as well as the evolution of additional regulatory networks that can modulate ribosome assembly and function, have resulted in a more complex assembly pathway in humans. Notably, many ribosome biogenesis factors conserved from yeast appear to have subtly different or additional functions in humans. In addition, recent genome-wide, RNAi-based screens have identified a plethora of novel factors required for human ribosome biogenesis. In this review, we discuss key aspects of human ribosome production, highlighting differences to yeast, links to disease, as well as emerging concepts such as extra-ribosomal functions of ribosomal proteins and ribosome heterogeneity.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular BiologyUniversity Medical Center GöttingenGöttingenGermany
| | - Markus T Bohnsack
- Department of Molecular BiologyUniversity Medical Center GöttingenGöttingenGermany
- Göttingen Center for Molecular BiosciencesGeorg‐August UniversityGöttingenGermany
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31
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Turi Z, Lacey M, Mistrik M, Moudry P. Impaired ribosome biogenesis: mechanisms and relevance to cancer and aging. Aging (Albany NY) 2019; 11:2512-2540. [PMID: 31026227 PMCID: PMC6520011 DOI: 10.18632/aging.101922] [Citation(s) in RCA: 116] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/04/2019] [Indexed: 02/06/2023]
Abstract
The biosynthesis of ribosomes is a complex process that requires the coordinated action of many factors and a huge energy investment from the cell. Ribosomes are essential for protein production, and thus for cellular survival, growth and proliferation. Ribosome biogenesis is initiated in the nucleolus and includes: the synthesis and processing of ribosomal RNAs, assembly of ribosomal proteins, transport to the cytoplasm and association of ribosomal subunits. The disruption of ribosome biogenesis at various steps, with either increased or decreased expression of different ribosomal components, can promote cell cycle arrest, senescence or apoptosis. Additionally, interference with ribosomal biogenesis is often associated with cancer, aging and age-related degenerative diseases. Here, we review current knowledge on impaired ribosome biogenesis, discuss the main factors involved in stress responses under such circumstances and focus on examples with clinical relevance.
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Affiliation(s)
- Zsofia Turi
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
| | - Matthew Lacey
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
| | - Martin Mistrik
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
| | - Pavel Moudry
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University, 779 00 Olomouc, Czech Republic
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32
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Sloan KE, Knox AA, Wells GR, Schneider C, Watkins NJ. Interactions and activities of factors involved in the late stages of human 18S rRNA maturation. RNA Biol 2019; 16:196-210. [PMID: 30638116 PMCID: PMC6380343 DOI: 10.1080/15476286.2018.1564467] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ribosome production is an essential cellular process involving a plethora of trans-acting factors, such as nucleases, methyltransferases, RNA helicases and kinases that catalyse key maturation steps. Precise temporal and spatial regulation of such enzymes is essential to ensure accurate and efficient subunit assembly. Here, we focus on the maturation of the 3ʹ end of the 18S rRNA in human cells. We reveal that human RIO2 is an active kinase that phosphorylates both itself and the rRNA methyltransferase DIM1 in vitro. In contrast to yeast, our data confirm that human DIM1 predominantly acts in the nucleus and we further demonstrate that the 21S pre-rRNA is the main target for DIM1-catalysed methylation. We show that the PIN domain of the endonuclease NOB1 is required for site 3 cleavage, while the zinc ribbon domain is essential for pre-40S recruitment. Furthermore, we also demonstrate that NOB1, PNO1 and DIM1 bind to a region of the pre-rRNA encompassing the 3ʹ end of 18S and the start of ITS1, in vitro. Interestingly, NOB1 is present in the cell at higher levels than other pre-40S factors. We provide evidence that NOB1 is multimeric within the cell and show that NOB1 multimerisation is lost when ribosome biogenesis is blocked. Taken together, our data indicate a dynamic interplay of key factors associated with the 3ʹ end of the 18S rRNA during human pre-40S biogenesis and highlight potential mechanisms by which this process can be regulated.
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Affiliation(s)
- Katherine Elizabeth Sloan
- a Institute for Cell and Molecular Biosciences, The Medical School , Newcastle University , Newcastle upon Tyne , UK.,b Department of Molecular Biology , University Medical Centre, Goettingen , Goettingen , Germany
| | - Andrew Alexander Knox
- a Institute for Cell and Molecular Biosciences, The Medical School , Newcastle University , Newcastle upon Tyne , UK
| | - Graeme Raymond Wells
- a Institute for Cell and Molecular Biosciences, The Medical School , Newcastle University , Newcastle upon Tyne , UK
| | - Claudia Schneider
- a Institute for Cell and Molecular Biosciences, The Medical School , Newcastle University , Newcastle upon Tyne , UK
| | - Nicholas James Watkins
- a Institute for Cell and Molecular Biosciences, The Medical School , Newcastle University , Newcastle upon Tyne , UK
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33
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Cao XZ, Forest MG. Rheological Tuning of Entangled Polymer Networks by Transient Cross-links. J Phys Chem B 2019; 123:974-982. [DOI: 10.1021/acs.jpcb.8b09357] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Xue-Zheng Cao
- Department of Mathematics and Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - M. Gregory Forest
- Department of Mathematics and Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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34
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TbUTP10, a protein involved in early stages of pre-18S rRNA processing in Trypanosoma brucei. Mol Biochem Parasitol 2018; 225:84-93. [PMID: 30248370 DOI: 10.1016/j.molbiopara.2018.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/28/2018] [Accepted: 09/15/2018] [Indexed: 12/19/2022]
Abstract
Ribosome biosynthesis, best studied in opisthokonts, is a highly complex process involving numerous protein and RNA factors. Yet, very little is known about the early stages of pre-18S rRNA processing even in these model organisms, let alone the conservation of this mechanism in other eukaryotes. Here we extend our knowledge of this process by identifying and characterizing the essential protein TbUTP10, a homolog of yeast U3 small nucleolar RNA-associated protein 10 - UTP10 (HEATR1 in human), in the excavate parasitic protist Trypanosoma brucei. We show that TbUTP10 localizes to the nucleolus and that its ablation by RNAi knock-down in two different T. brucei life cycle stages results in similar phenotypes: a disruption of pre-18S rRNA processing, exemplified by the accumulation of rRNA precursors, a reduction of mature 18S rRNA, and also a decrease in the level of U3 snoRNA. Moreover, polysome profiles of the RNAi-induced knock-down cells show a complete disappearance of the 40S ribosomal subunit, and a prominent accumulation of the 60S large ribosomal subunit, reflecting impaired ribosome assembly. Thus, TbUTP10 is an important protein in the processing of 18S rRNA.
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35
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Werner A, Baur R, Teerikorpi N, Kaya DU, Rape M. Multisite dependency of an E3 ligase controls monoubiquitylation-dependent cell fate decisions. eLife 2018; 7:35407. [PMID: 29999490 PMCID: PMC6057744 DOI: 10.7554/elife.35407] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 07/07/2018] [Indexed: 12/31/2022] Open
Abstract
Metazoan development depends on tightly regulated gene expression programs that instruct progenitor cells to adopt specialized fates. Recent work found that posttranslational modifications, such as monoubiquitylation, can determine cell fate also independently of effects on transcription, yet how monoubiquitylation is implemented during development is poorly understood. Here, we have identified a regulatory circuit that controls monoubiquitylation-dependent neural crest specification by the E3 ligase CUL3 and its substrate adaptor KBTBD8. We found that CUL3KBTBD8 monoubiquitylates its essential targets only after these have been phosphorylated in multiple motifs by CK2, a kinase whose levels gradually increase during embryogenesis. Its dependency on multisite phosphorylation allows CUL3KBTBD8 to convert the slow rise in embryonic CK2 into decisive recognition of ubiquitylation substrates, which in turn is essential for neural crest specification. We conclude that multisite dependency of an E3 ligase provides a powerful mechanism for switch-like cell fate transitions controlled by monoubiquitylation.
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Affiliation(s)
- Achim Werner
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Regina Baur
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Nia Teerikorpi
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Deniz U Kaya
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Michael Rape
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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36
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Arimbasseri GA. Interactions between RNAP III transcription machinery and tRNA processing factors. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:354-360. [PMID: 29428193 DOI: 10.1016/j.bbagrm.2018.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 10/18/2022]
Abstract
Eukaryotes have at least three nuclear RNA polymerases to carry out transcription. While RNA polymerases I and II are responsible for ribosomal RNA transcription and messenger RNA transcription, respectively, RNA Polymerase III transcribes approximately up to 300 nt long noncoding RNAs, including tRNA. For all three RNAPs, the nascent transcripts generated undergo extensive post-transcriptional processing. Transcription of mRNAs by RNAP II and their processing are coupled with the aid of the C-terminal domain of the RNAP II. RNAP I transcription and the processing of its transcripts are co-localized to the nucleolus and to some extent, rRNA processing occurs co-transcriptionally. Here, I review the current evidence for the interaction between tRNA processing factors and RNA polymerase III. These interactions include the moonlighting functions of tRNA processing factors in RNAP III transcription and the indirect effect of tRNA transcription levels on tRNA modification machinery.
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Affiliation(s)
- G Aneeshkumar Arimbasseri
- Molecular Genetics Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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37
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Abstract
Ribosome biogenesis is a complex and highly energy-demanding process that requires the concerted action of all three nuclear RNA polymerases (Pol I-III) in eukaryotes. The three largest ribosomal RNAs (rRNAs) originate from a precursor transcript (pre-rRNA) that is encoded by multicopy genes located in the nucleolus. Transcription of these rRNA genes (rDNA) by Pol I is the key regulation step in ribosome production and is tightly controlled by an intricate network of signaling pathways and epigenetic mechanisms. In this article, we give an overview of the composition of the basal Pol I machinery and rDNA chromatin. We discuss rRNA gene regulation in response to environmental signals and developmental cues and focus on perturbations occurring in diseases linked to either excessive or limited rRNA levels. Finally, we discuss the emerging view that rDNA integrity and activity may be involved in the aging process.
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Affiliation(s)
- Samim Sharifi
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University, 07745 Jena, Germany; , .,Leibniz-Institute on Aging-Fritz Lipmann Institute, 07745 Jena, Germany
| | - Holger Bierhoff
- Institute of Biochemistry and Biophysics, Center for Molecular Biomedicine, Friedrich Schiller University, 07745 Jena, Germany; , .,Leibniz-Institute on Aging-Fritz Lipmann Institute, 07745 Jena, Germany
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38
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Abstract
The nucleolus is the largest nuclear sub-compartment in which the early steps of ribosome biogenesis take place. It also plays an essential role in the assembly and function of non-ribosomal ribonucleoprotein (RNP) complexes, controls cell cycle progression and senses environmental stress. The spatial organization and dynamics of nucleolar proteins and RNA is regulated at different structural levels, which finally determine nucleolar architecture. The intimate link between nucleolar structure and function is reflected by transcription-dependent changes in nucleolus-associated chromatin, overall morphological alterations in response to external cues, and the liquid droplet-like behavior of nucleolar compartments. Here we provide a concise overview of the latest studies which integrate novel trends in nucleolar architecture research into the context of cell biology.
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Affiliation(s)
- Attila Németh
- Institute of Neuropathology, University of Giessen, Germany.
| | - Ingrid Grummt
- Molecular Biology of the Cell II, German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany.
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39
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Affiliation(s)
- Slađana Bursać
- a Department of Molecular Medicine and Biotechnology, School of Medicine , University of Rijeka , Brace Branchetta 20, 51000 Rijeka , Croatia.,b Scientific Center of Excellence for Reproductive and Regenerative Medicine , University of Rijeka , Brace Branchetta 20, 51000 Rijeka , Croatia
| | - Deana Jurada
- a Department of Molecular Medicine and Biotechnology, School of Medicine , University of Rijeka , Brace Branchetta 20, 51000 Rijeka , Croatia.,b Scientific Center of Excellence for Reproductive and Regenerative Medicine , University of Rijeka , Brace Branchetta 20, 51000 Rijeka , Croatia
| | - Siniša Volarević
- a Department of Molecular Medicine and Biotechnology, School of Medicine , University of Rijeka , Brace Branchetta 20, 51000 Rijeka , Croatia.,b Scientific Center of Excellence for Reproductive and Regenerative Medicine , University of Rijeka , Brace Branchetta 20, 51000 Rijeka , Croatia
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40
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Warren AJ. Molecular basis of the human ribosomopathy Shwachman-Diamond syndrome. Adv Biol Regul 2018; 67:109-127. [PMID: 28942353 PMCID: PMC6710477 DOI: 10.1016/j.jbior.2017.09.002] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 01/05/2023]
Abstract
Mutations that target the ubiquitous process of ribosome assembly paradoxically cause diverse tissue-specific disorders (ribosomopathies) that are often associated with an increased risk of cancer. Ribosomes are the essential macromolecular machines that read the genetic code in all cells in all kingdoms of life. Following pre-assembly in the nucleus, precursors of the large 60S and small 40S ribosomal subunits are exported to the cytoplasm where the final steps in maturation are completed. Here, I review the recent insights into the conserved mechanisms of ribosome assembly that have come from functional characterisation of the genes mutated in human ribosomopathies. In particular, recent advances in cryo-electron microscopy, coupled with genetic, biochemical and prior structural data, have revealed that the SBDS protein that is deficient in the inherited leukaemia predisposition disorder Shwachman-Diamond syndrome couples the final step in cytoplasmic 60S ribosomal subunit maturation to a quality control assessment of the structural and functional integrity of the nascent particle. Thus, study of this fascinating disorder is providing remarkable insights into how the large ribosomal subunit is functionally activated in the cytoplasm to enter the actively translating pool of ribosomes.
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MESH Headings
- Bone Marrow Diseases/metabolism
- Bone Marrow Diseases/pathology
- Cryoelectron Microscopy
- Exocrine Pancreatic Insufficiency/metabolism
- Exocrine Pancreatic Insufficiency/pathology
- Humans
- Lipomatosis/metabolism
- Lipomatosis/pathology
- Mutation
- Proteins/genetics
- Proteins/metabolism
- Ribosome Subunits, Large, Eukaryotic/genetics
- Ribosome Subunits, Large, Eukaryotic/metabolism
- Ribosome Subunits, Large, Eukaryotic/ultrastructure
- Ribosome Subunits, Small, Eukaryotic/genetics
- Ribosome Subunits, Small, Eukaryotic/metabolism
- Ribosome Subunits, Small, Eukaryotic/ultrastructure
- Shwachman-Diamond Syndrome
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Affiliation(s)
- Alan J Warren
- Cambridge Institute for Medical Research, Cambridge, UK; The Department of Haematology, University of Cambridge, Cambridge, UK; Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, UK.
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41
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Turi Z, Senkyrikova M, Mistrik M, Bartek J, Moudry P. Perturbation of RNA Polymerase I transcription machinery by ablation of HEATR1 triggers the RPL5/RPL11-MDM2-p53 ribosome biogenesis stress checkpoint pathway in human cells. Cell Cycle 2017; 17:92-101. [PMID: 29143558 DOI: 10.1080/15384101.2017.1403685] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ribosome biogenesis is an energy consuming process which takes place mainly in the nucleolus. By producing ribosomes to fuel protein synthesis, it is tightly connected with cell growth and cell cycle control. Perturbation of ribosome biogenesis leads to the activation of p53 tumor suppressor protein promoting processes like cell cycle arrest, apoptosis or senescence. This ribosome biogenesis stress pathway activates p53 through sequestration of MDM2 by a subset of ribosomal proteins (RPs), thereby stabilizing p53. Here, we identify human HEATR1, as a nucleolar protein which positively regulates ribosomal RNA (rRNA) synthesis. Downregulation of HEATR1 resulted in cell cycle arrest in a manner dependent on p53. Moreover, depletion of HEATR1 also caused disruption of nucleolar structure and activated the ribosomal biogenesis stress pathway - RPL5 / RPL11 dependent stabilization and activation of p53. These findings reveal an important role for HEATR1 in ribosome biogenesis and further support the concept that perturbation of ribosome biosynthesis results in p53-dependent cell cycle checkpoint activation, with implications for human pathologies including cancer.
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Affiliation(s)
- Zsofia Turi
- a Institute of Molecular and Translational Medicine , Faculty of Medicine and Dentistry , Palacky University , 779 00 Olomouc , Czech Republic
| | - Marketa Senkyrikova
- a Institute of Molecular and Translational Medicine , Faculty of Medicine and Dentistry , Palacky University , 779 00 Olomouc , Czech Republic
| | - Martin Mistrik
- a Institute of Molecular and Translational Medicine , Faculty of Medicine and Dentistry , Palacky University , 779 00 Olomouc , Czech Republic
| | - Jiri Bartek
- a Institute of Molecular and Translational Medicine , Faculty of Medicine and Dentistry , Palacky University , 779 00 Olomouc , Czech Republic.,b Genome Integrity Unit , Danish Cancer Society Research Center , DK-2100 Copenhagen , Denmark.,c Department of Medical Biochemistry and Biophysics , Division of Genome Biology , Science for Life Laboratory , Karolinska Institute , 171 65 Stockholm , Sweden
| | - Pavel Moudry
- a Institute of Molecular and Translational Medicine , Faculty of Medicine and Dentistry , Palacky University , 779 00 Olomouc , Czech Republic
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42
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Hult C, Adalsteinsson D, Vasquez PA, Lawrimore J, Bennett M, York A, Cook D, Yeh E, Forest MG, Bloom K. Enrichment of dynamic chromosomal crosslinks drive phase separation of the nucleolus. Nucleic Acids Res 2017; 45:11159-11173. [PMID: 28977453 PMCID: PMC5737219 DOI: 10.1093/nar/gkx741] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Revised: 08/07/2017] [Accepted: 08/14/2017] [Indexed: 01/24/2023] Open
Abstract
Regions of highly repetitive DNA, such as those found in the nucleolus, show a self-organization that is marked by spatial segregation and frequent self-interaction. The mechanisms that underlie the sequestration of these sub-domains are largely unknown. Using a stochastic, bead-spring representation of chromatin in budding yeast, we find enrichment of protein-mediated, dynamic chromosomal cross-links recapitulates the segregation, morphology and self-interaction of the nucleolus. Rates and enrichment of dynamic crosslinking have profound consequences on domain morphology. Our model demonstrates the nucleolus is phase separated from other chromatin in the nucleus and predicts that multiple rDNA loci will form a single nucleolus independent of their location within the genome. Fluorescent labeling of budding yeast nucleoli with CDC14-GFP revealed that a split rDNA locus indeed forms a single nucleolus. We propose that nuclear sub-domains, such as the nucleolus, result from phase separations within the nucleus, which are driven by the enrichment of protein-mediated, dynamic chromosomal crosslinks.
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Affiliation(s)
- Caitlin Hult
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - David Adalsteinsson
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Paula A. Vasquez
- Department of Mathematics, University of South Carolina, Columbia, SC 29808, USA
| | - Josh Lawrimore
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum of Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Maggie Bennett
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Alyssa York
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Diana Cook
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Elaine Yeh
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Mark Gregory Forest
- Department of Mathematics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kerry Bloom
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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43
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Internal Associations of the Acidic Region of Upstream Binding Factor Control Its Nucleolar Localization. Mol Cell Biol 2017; 37:MCB.00218-17. [PMID: 28874518 DOI: 10.1128/mcb.00218-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/25/2017] [Indexed: 01/24/2023] Open
Abstract
Upstream binding factor (UBF) is a member of the high-mobility group (HMG) box protein family, characterized by multiple HMG boxes and a C-terminal acidic region (AR). UBF is an essential transcription factor for rRNA genes and mediates the formation of transcriptionally active chromatin in the nucleolus. However, it remains unknown how UBF is specifically localized to the nucleolus. Here, we examined the molecular mechanisms that localize UBF to the nucleolus. We found that the first HMG box (HMG box 1), the linker region (LR), and the AR cooperatively regulate the nucleolar localization of UBF1. We demonstrated that the AR intramolecularly associates with and attenuates the DNA binding activity of HMG boxes and confers the structured DNA preference to HMG box 1. In contrast, the LR was found to serve as a nuclear localization signal and compete with HMG boxes to bind the AR, permitting nucleolar localization of UBF1. The LR sequence binds DNA and assists the stable chromatin binding of UBF. We also showed that the phosphorylation status of the AR does not clearly affect the localization of UBF1. Our results strongly suggest that associations of the AR with HMG boxes and the LR regulate UBF nucleolar localization.
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44
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Mangan H, Gailín MÓ, McStay B. Integrating the genomic architecture of human nucleolar organizer regions with the biophysical properties of nucleoli. FEBS J 2017; 284:3977-3985. [PMID: 28500793 DOI: 10.1111/febs.14108] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 04/21/2017] [Accepted: 05/10/2017] [Indexed: 11/30/2022]
Abstract
Nucleoli are the sites of ribosome biogenesis and the largest membraneless subnuclear structures. They are intimately linked with growth and proliferation control and function as sensors of cellular stress. Nucleoli form around arrays of ribosomal gene (rDNA) repeats also called nucleolar organizer regions (NORs). In humans, NORs are located on the short arms of all five human acrocentric chromosomes. Multiple NORs contribute to the formation of large heterochromatin-surrounded nucleoli observed in most human cells. Here we will review recent findings about their genomic architecture. The dynamic nature of nucleoli began to be appreciated with the advent of photodynamic experiments using fluorescent protein fusions. We review more recent data on nucleoli in Xenopus germinal vesicles (GVs) which has revealed a liquid droplet-like behavior that facilitates nucleolar fusion. Further analysis in both XenopusGVs and Drosophila embryos indicates that the internal organization of nucleoli is generated by a combination of liquid-liquid phase separation and active processes involving rDNA. We will attempt to integrate these recent findings with the genomic architecture of human NORs to advance our understanding of how nucleoli form and respond to stress in human cells.
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Affiliation(s)
- Hazel Mangan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Ireland
| | - Michael Ó Gailín
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Ireland
| | - Brian McStay
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Ireland
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45
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Nucleolar reorganization in response to rDNA damage. Curr Opin Cell Biol 2017; 46:81-86. [PMID: 28431265 DOI: 10.1016/j.ceb.2017.03.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 02/06/2017] [Accepted: 03/07/2017] [Indexed: 11/24/2022]
Abstract
Nucleoli, sites of ribosome biogenesis, form around nucleolar organizer regions (NORs) comprising rDNA arrays, located on human acrocentric chromosome p-arms. NORs provide an opportunity to investigate the DNA double strand break (DSB) response at highly transcribed, repetitive, essential loci. Targeted introduction of DSBs into rDNA results in ATM-dependent inhibition of RNA-polymerase I transcription, coupled with movement of rDNA from the nucleolar interior to anchoring points at the periphery. Reorganization renders rDNA accessible to repair factors, normally excluded from nucleoli. Importantly, rDNA DSBs recruit the accurate homologous recombination (HR) repair machinery throughout the cell cycle, suggesting that HR can be templated in cis. We discuss recent findings regarding the biophysical properties of nucleoli and suggest a mechanism for stress-induced nucleolar reorganization.
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46
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Ren R, Deng L, Xue Y, Suzuki K, Zhang W, Yu Y, Wu J, Sun L, Gong X, Luan H, Yang F, Ju Z, Ren X, Wang S, Tang H, Geng L, Zhang W, Li J, Qiao J, Xu T, Qu J, Liu GH. Visualization of aging-associated chromatin alterations with an engineered TALE system. Cell Res 2017; 27:483-504. [PMID: 28139645 PMCID: PMC5385610 DOI: 10.1038/cr.2017.18] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 12/06/2016] [Accepted: 12/28/2016] [Indexed: 02/07/2023] Open
Abstract
Visualization of specific genomic loci in live cells is a prerequisite for the investigation of dynamic changes in chromatin architecture during diverse biological processes, such as cellular aging. However, current precision genomic imaging methods are hampered by the lack of fluorescent probes with high specificity and signal-to-noise contrast. We find that conventional transcription activator-like effectors (TALEs) tend to form protein aggregates, thereby compromising their performance in imaging applications. Through screening, we found that fusing thioredoxin with TALEs prevented aggregate formation, unlocking the full power of TALE-based genomic imaging. Using thioredoxin-fused TALEs (TTALEs), we achieved high-quality imaging at various genomic loci and observed aging-associated (epi) genomic alterations at telomeres and centromeres in human and mouse premature aging models. Importantly, we identified attrition of ribosomal DNA repeats as a molecular marker for human aging. Our study establishes a simple and robust imaging method for precisely monitoring chromatin dynamics in vitro and in vivo.
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Affiliation(s)
- Ruotong Ren
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liping Deng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanhong Xue
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Keiichiro Suzuki
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Weiqi Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Yu
- Department of Gynecology and Obstetrics, Peking University Third Hospital, Beijing 100191, China
| | - Jun Wu
- Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Liang Sun
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, China
| | - Xiaojun Gong
- Department of Pediatrics, Beijing Shijitan Hospital Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing 100038, China
| | - Huiqin Luan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fan Yang
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, Guangdong 510632, China
| | - Zhenyu Ju
- Institute of Aging Research, Hangzhou Normal University School of Medicine, Hangzhou, Zhejiang 311121, China
| | - Xiaoqing Ren
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Si Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hong Tang
- Department of Pediatrics, Beijing Shijitan Hospital Capital Medical University, Peking University Ninth School of Clinical Medicine, Beijing 100038, China
| | - Lingling Geng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Weizhou Zhang
- Department of Pathology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Jian Li
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, China
| | - Jie Qiao
- Department of Gynecology and Obstetrics, Peking University Third Hospital, Beijing 100191, China
| | - Tao Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Qu
- University of Chinese Academy of Sciences, Beijing 100049, China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guang-Hui Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, Guangdong 510632, China
- Beijing Institute for Brain Disorders, Beijing 100069, China
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47
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Guo F, Chen JJ, Tang WJ. CIRH1A augments the proliferation of RKO colorectal cancer cells. Oncol Rep 2017; 37:2375-2381. [PMID: 28350096 DOI: 10.3892/or.2017.5497] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 01/18/2017] [Indexed: 11/06/2022] Open
Abstract
Accumulating evidence suggests that ribosomal proteins may have extraribosomal functions in various physiological and pathological processes, including cancer. We analyzed the expression of the CIRH1A ribosomal protein in colorectal carcinoma and para-carcinoma samples by bioinformatics analyses of data extracted from The Cancer Genome Atlas and in colorectal cancer cell lines in vitro by qPCR. CIRH1A was highly expressed in carcinoma samples and colorectal cancer cells. We also transduced the RKO colorectal cancer (CRC) cell line with lentivirus-mediated small interfering RNAs (siRNAs) and studied the impact that this knockdown of CIRH1A expression had on cell growth. RNA interference (RNAi)-mediated inhibition of CIRH1A expression significantly suppressed proliferation and increased apoptosis of transduced cells, and tended to arrest them in G1 phase. Our data suggest that CIRH1A plays a critical role in the proliferation, cell cycle distribution, and apoptosis of human malignant colorectal cells, and might therefore be a potential target for therapeutic strategies.
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Affiliation(s)
- Feng Guo
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, P.R. China
| | - Jian-Jun Chen
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, P.R. China
| | - Wei-Jun Tang
- Department of Gastrointestinal Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, P.R. China
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48
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Abstract
SIRT7, a member of the sirtuin family of NAD+-dependent protein deacetylases, is a key mediator of many cellular activities. SIRT7 expression is linked to cell proliferation and oncogenic activity, connecting SIRT7-dependent regulation of ribosome biogenesis with checkpoints controlling cell cycle progression, metabolic homeostasis, stress resistance, aging and tumorigenesis. Despite this important functional link, the enzymatic activity, the molecular targets and physiological functions of SIRT7 are poorly defined. Here, we review recent progress in SIRT7 research and elaborate the main pathways in which SIRT7 participates.
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Affiliation(s)
- Maximilian F Blank
- a Molecular Biology of the Cell II , German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance , Heidelberg , Germany
| | - Ingrid Grummt
- a Molecular Biology of the Cell II , German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance , Heidelberg , Germany
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49
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Abstract
Nucleoli form around tandem arrays of a ribosomal gene repeat, termed nucleolar organizer regions (NORs). During metaphase, active NORs adopt a characteristic undercondensed morphology. Recent evidence indicates that the HMG-box-containing DNA-binding protein UBF (upstream binding factor) is directly responsible for this morphology and provides a mitotic bookmark to ensure rapid nucleolar formation beginning in telophase in human cells. This is likely to be a widely employed strategy, as UBF is present throughout metazoans. In higher eukaryotes, NORs are typically located within regions of chromosomes that form perinucleolar heterochromatin during interphase. Typically, the genomic architecture of NORs and the chromosomal regions within which they lie is very poorly described, yet recent evidence points to a role for context in their function. In Arabidopsis, NOR silencing appears to be controlled by sequences outside the rDNA (ribosomal DNA) array. Translocations reveal a role for context in the expression of the NOR on the X chromosome in Drosophila Recent work has begun on characterizing the genomic architecture of human NORs. A role for distal sequences located in perinucleolar heterochromatin has been inferred, as they exhibit a complex transcriptionally active chromatin structure. Links between rDNA genomic stability and aging in Saccharomyces cerevisiae are now well established, and indications are emerging that this is important in aging and replicative senescence in higher eukaryotes. This, combined with the fact that rDNA arrays are recombinational hot spots in cancer cells, has focused attention on DNA damage responses in NORs. The introduction of DNA double-strand breaks into rDNA arrays leads to a dramatic reorganization of nucleolar structure. Damaged rDNA repeats move from the nucleolar interior to form caps at the nucleolar periphery, presumably to facilitate repair, suggesting that the chromosomal context of human NORs contributes to their genomic stability. The inclusion of NORs and their surrounding chromosomal environments in future genome drafts now becomes a priority.
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Affiliation(s)
- Brian McStay
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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50
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Sondalle SB, Baserga SJ, Yelick PC. The Contributions of the Ribosome Biogenesis Protein Utp5/WDR43 to Craniofacial Development. J Dent Res 2016; 95:1214-20. [PMID: 27221611 DOI: 10.1177/0022034516651077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Fairly recently, it was recognized that human ribosomopathies-developmental defects caused by mutations in ribosome biogenesis proteins-can exhibit tissue-specific defects rather than the expected global defects. This apparent anomaly-that seemingly ubiquitously expressed and required ribosomal proteins can have distinct functions in cell and tissue differentiation-has spurred new areas of research focused on better understanding translational mechanisms, biogenesis, and function in diverse cell types. This renewed appreciation for, and need to better understand, roles for ribosomal proteins in human development and disease has identified surprising similarities and differences in a variety of human ribosomopathies. Here, we discuss ribosomal protein functions in health and disease, focusing on the ribosome biogenesis protein Utp5/WDR43. New and exciting research in this field is anticipated to provide insight into a variety of previously understudied craniofacial dysostoses and result in significantly improved knowledge and understanding of roles for translational machinery in human craniofacial development and disease.
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Affiliation(s)
- S B Sondalle
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - S J Baserga
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA
| | - P C Yelick
- Department of Orthodontics, Division of Craniofacial and Molecular Genetics, Tufts University, Boston, MA, USA
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