201
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Wang M, Chen Y, Wang Y, Li Y, Zhang X, Zheng H, Ma F, Ma C, Lu B, Xie Z, Liao Q. Beneficial changes of gut microbiota and metabolism in weaned rats with Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 supplementation. J Funct Foods 2018. [DOI: 10.1016/j.jff.2018.07.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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202
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Gantenbein N, Bernhart E, Anders I, Golob-Schwarzl N, Krassnig S, Wodlej C, Brcic L, Lindenmann J, Fink-Neuboeck N, Gollowitsch F, Stacher-Priehse E, Asslaber M, Gogg-Kamerer M, Rolff J, Hoffmann J, Silvestri A, Regenbrecht C, Reinhard C, Pehserl AM, Pichler M, Sokolova O, Naumann M, Mitterer V, Pertschy B, Bergler H, Popper H, Sattler W, Haybaeck J. Influence of eukaryotic translation initiation factor 6 on non-small cell lung cancer development and progression. Eur J Cancer 2018; 101:165-180. [PMID: 30077122 DOI: 10.1016/j.ejca.2018.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 06/22/2018] [Accepted: 07/02/2018] [Indexed: 12/12/2022]
Abstract
Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. Dysregulation of protein synthesis plays a major role in carcinogenesis, a process regulated at multiple levels, including translation of mRNA into proteins. Ribosome assembly requires correct association of ribosome subunits, which is ensured by eukaryotic translation initiation factors (eIFs). eIFs have become targets in cancer therapy studies, and promising data on eIF6 in various cancer entities have been reported. Therefore, we hypothesised that eIF6 represents a crossroad for pulmonary carcinogenesis. High levels of eIF6 are associated with shorter patient overall survival in adenocarcinoma (ADC), but not in squamous cell carcinoma (SQC) of the lung. We demonstrate significantly higher protein expression of eIF6 in ADC and SQC than in healthy lung tissue based on immunohistochemical data from tissue microarrays (TMAs) and on fresh frozen lung tissue. Depletion of eIF6 in ADC and SQC lung cancer cell lines inhibited cell proliferation and induced apoptosis. Knockdown of eIF6 led to pre-rRNA processing and ribosomal 60S maturation defects. Our data indicate that eIF6 is upregulated in NSCLC, suggesting an important contribution of eIF6 to the development and progression of NSCLC and a potential for new treatment strategies against NSCLC.
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Affiliation(s)
- Nadine Gantenbein
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria; Center for Biomarker Research in Medicine, Stiftingtalstrasse 5, 8010 Graz, Austria
| | - Eva Bernhart
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Ines Anders
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Nicole Golob-Schwarzl
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria; Center for Biomarker Research in Medicine, Stiftingtalstrasse 5, 8010 Graz, Austria
| | - Stefanie Krassnig
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Christina Wodlej
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria; Center for Biomarker Research in Medicine, Stiftingtalstrasse 5, 8010 Graz, Austria
| | - Luka Brcic
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Joerg Lindenmann
- Division of Thoracic and Hyperbaric Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria
| | - Nicole Fink-Neuboeck
- Division of Thoracic and Hyperbaric Surgery, Medical University of Graz, Auenbruggerplatz 29, 8036 Graz, Austria
| | - Franz Gollowitsch
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Elvira Stacher-Priehse
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Martin Asslaber
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Margit Gogg-Kamerer
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Jana Rolff
- Experimental Pharmacology & Oncology Berlin GmbH-Berlin-Buch, Robert-Rössle-Str. 10, 13125 Berlin-Buch, Germany
| | - Jens Hoffmann
- Experimental Pharmacology & Oncology Berlin GmbH-Berlin-Buch, Robert-Rössle-Str. 10, 13125 Berlin-Buch, Germany
| | - Alessandra Silvestri
- Cpo - Cellular Phenomics & Oncology Berlin-Buch GmbH, Robert-Rössle-Str. 10, 13125 Berlin-Buch, Germany
| | - Christian Regenbrecht
- Cpo - Cellular Phenomics & Oncology Berlin-Buch GmbH, Robert-Rössle-Str. 10, 13125 Berlin-Buch, Germany
| | - Christoph Reinhard
- Eli Lilly & Company, Lilly Corporate Center, 46285 Indiana, Indianapolis, USA
| | - Anna-Maria Pehserl
- Division of Oncology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Martin Pichler
- Division of Oncology, Medical University of Graz, Auenbruggerplatz 15, 8036 Graz, Austria
| | - Olga Sokolova
- Institute of Experimental Internal Medicine, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
| | - Valentin Mitterer
- Institute of Molecular Biosciences, Karl-Franzens-University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Brigitte Pertschy
- Institute of Molecular Biosciences, Karl-Franzens-University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Helmut Bergler
- Institute of Molecular Biosciences, Karl-Franzens-University of Graz, Humboldtstraße 50, 8010 Graz, Austria
| | - Helmut Popper
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Wolfgang Sattler
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Molecular Biology and Biochemistry, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria
| | - Johannes Haybaeck
- Diagnostic and Research Institute of Pathology, Medical University of Graz, Neue Stiftingtalstrasse 6, 8010 Graz, Austria; Center for Biomarker Research in Medicine, Stiftingtalstrasse 5, 8010 Graz, Austria; Department of Pathology, Medical Faculty, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
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203
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Gerlach P, Schuller JM, Bonneau F, Basquin J, Reichelt P, Falk S, Conti E. Distinct and evolutionary conserved structural features of the human nuclear exosome complex. eLife 2018; 7:38686. [PMID: 30047866 PMCID: PMC6072439 DOI: 10.7554/elife.38686] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022] Open
Abstract
The nuclear RNA exosome complex mediates the processing of structured RNAs and the decay of aberrant non-coding RNAs, an important function particularly in human cells. Most mechanistic studies to date have focused on the yeast system. Here, we reconstituted and studied the properties of a recombinant 14-subunit human nuclear exosome complex. In biochemical assays, the human exosome embeds a longer RNA channel than its yeast counterpart. The 3.8 Å resolution cryo-EM structure of the core complex bound to a single-stranded RNA reveals that the RNA channel path is formed by two distinct features of the hDIS3 exoribonuclease: an open conformation and a domain organization more similar to bacterial RNase II than to yeast Rrp44. The cryo-EM structure of the holo-complex shows how obligate nuclear cofactors position the hMTR4 helicase at the entrance of the core complex, suggesting a striking structural conservation from lower to higher eukaryotes.
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Affiliation(s)
- Piotr Gerlach
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
| | - Jan M Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
| | - Fabien Bonneau
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
| | - Jérôme Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
| | - Peter Reichelt
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
| | - Sebastian Falk
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Munich, Germany
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204
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Muto A, Sugihara Y, Shibakawa M, Oshima K, Matsuda T, Nadano D. The mRNA-binding protein Serbp1 as an auxiliary protein associated with mammalian cytoplasmic ribosomes. Cell Biochem Funct 2018; 36:312-322. [PMID: 30039520 DOI: 10.1002/cbf.3350] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 04/23/2018] [Accepted: 06/26/2018] [Indexed: 01/27/2023]
Abstract
While transcription plays an obviously important role in gene expression, translation has recently been emerged as a key step that defines the composition and quality of the proteome in the cell of higher eukaryotes including mammals. Selective translation is supposed to be regulated by the structural heterogeneity of cytoplasmic ribosomes including differences in protein composition and chemical modifications. However, the current knowledge on the heterogeneity of mammalian ribosomes is limited. Here, we report mammalian Serbp1 as a ribosome-associated protein. The translated products of Serbp1 gene, including the longest isoform, were found to be localized in the nucleolus as well as in the cytoplasm. Subcellular fractionation indicated that most of cytoplasmic Serbp1 molecules were precipitated by ultracentrifugation. Proteomic analysis identified Serbp1 in the cytoplasmic ribosomes of the rodent testis. Polysome profiling suggested that Serbp1, as a component of the small 40S subunit, was included in translating ribosomes (polysomes). Cosedimentation of Serbp1 with the 40S subunit was observed after dissociation of the ribosomal subunits. Serbp1 was also included in the ribosomes of human cancer cells, which may lead to a mechanistic understanding of an emerging link between Serbp1 and tumour progression. SIGNIFICANCE OF THE STUDY In mammalian cells, the final protein output of their genetic program is determined not only by controlling transcription but also by regulating the posttranscriptional events. Although mRNA-binding proteins and the cytoplasmic ribosome have long been recognized as central players in the posttranscriptional regulation, their physical and functional interactions are still far from a complete understanding. Here, we describe the intracellular localization of Serbp1, an mRNA-binding protein, and the inclusion of this protein in actively translating ribosomes in normal and cancer cells. These findings shed a new light into molecular mechanisms underlying Serbp1 action in translational gene regulation and tumour progression.
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Affiliation(s)
- Akiko Muto
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yoshihiko Sugihara
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Minami Shibakawa
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Kenzi Oshima
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Tsukasa Matsuda
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Daita Nadano
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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205
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The Conserved RNA Exonuclease Rexo5 Is Required for 3' End Maturation of 28S rRNA, 5S rRNA, and snoRNAs. Cell Rep 2018; 21:758-772. [PMID: 29045842 DOI: 10.1016/j.celrep.2017.09.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 07/16/2017] [Accepted: 09/20/2017] [Indexed: 12/21/2022] Open
Abstract
Non-coding RNA biogenesis in higher eukaryotes has not been fully characterized. Here, we studied the Drosophila melanogaster Rexo5 (CG8368) protein, a metazoan-specific member of the DEDDh 3'-5' single-stranded RNA exonucleases, by genetic, biochemical, and RNA-sequencing approaches. Rexo5 is required for small nucleolar RNA (snoRNA) and rRNA biogenesis and is essential in D. melanogaster. Loss-of-function mutants accumulate improperly 3' end-trimmed 28S rRNA, 5S rRNA, and snoRNA precursors in vivo. Rexo5 is ubiquitously expressed at low levels in somatic metazoan cells but extremely elevated in male and female germ cells. Loss of Rexo5 leads to increased nucleolar size, genomic instability, defective ribosome subunit export, and larval death. Loss of germline expression compromises gonadal growth and meiotic entry during germline development.
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206
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Ameismeier M, Cheng J, Berninghausen O, Beckmann R. Visualizing late states of human 40S ribosomal subunit maturation. Nature 2018; 558:249-253. [PMID: 29875412 DOI: 10.1038/s41586-018-0193-0] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 04/20/2018] [Indexed: 01/24/2023]
Abstract
The formation of eukaryotic ribosomal subunits extends from the nucleolus to the cytoplasm and entails hundreds of assembly factors. Despite differences in the pathways of ribosome formation, high-resolution structural information has been available only from fungi. Here we present cryo-electron microscopy structures of late-stage human 40S assembly intermediates, representing one state reconstituted in vitro and five native states that range from nuclear to late cytoplasmic. The earliest particles reveal the position of the biogenesis factor RRP12 and distinct immature rRNA conformations that accompany the formation of the 40S subunit head. Molecular models of the late-acting assembly factors TSR1, RIOK1, RIOK2, ENP1, LTV1, PNO1 and NOB1 provide mechanistic details that underlie their contribution to a sequential 40S subunit assembly. The NOB1 architecture displays an inactive nuclease conformation that requires rearrangement of the PNO1-bound 3' rRNA, thereby coordinating the final rRNA folding steps with site 3 cleavage.
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Affiliation(s)
- Michael Ameismeier
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany
| | - Jingdong Cheng
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany
| | - Otto Berninghausen
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany
| | - Roland Beckmann
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany.
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207
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Hayashi Y, Fujimura A, Kato K, Udagawa R, Hirota T, Kimura K. Nucleolar integrity during interphase supports faithful Cdk1 activation and mitotic entry. SCIENCE ADVANCES 2018; 4:eaap7777. [PMID: 29881774 PMCID: PMC5990311 DOI: 10.1126/sciadv.aap7777] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 04/26/2018] [Indexed: 06/08/2023]
Abstract
The nucleolus is a dynamic nuclear body that has been demonstrated to disassemble at the onset of mitosis; the relationship between cell cycle progression and nucleolar integrity, however, remains poorly understood. We studied the role of nucleolar proteins in mitosis by performing a global analysis using small interfering RNAs specific to nucleolar proteins; we focused on nucleolar protein 11 (NOL11), with currently unknown mitotic functions. Depletion of NOL11 delayed entry into the mitotic phase owing to increased inhibitory phosphorylation of cyclin-dependent kinase 1 (Cdk1) and aberrant accumulation of Wee1, a kinase that phosphorylates and inhibits Cdk1. In addition to effects on overall mitotic phenotypes, NOL11 depletion reduced ribosomal RNA (rRNA) levels and caused nucleolar disruption during interphase. Notably, mitotic phenotypes found in NOL11-depleted cells were recapitulated when nucleolar disruption was induced by depletion of rRNA transcription factors or treatment with actinomycin D. Furthermore, delayed entry into the mitotic phase, caused by the depletion of pre-rRNA transcription factors, was attributable to nucleolar disruption rather than to G2/M checkpoint activation or reduced protein synthesis. Our findings therefore suggest that maintenance of nucleolar integrity during interphase is essential for proper cell cycle progression to mitosis via the regulation of Wee1 and Cdk1.
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Affiliation(s)
- 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, Ibaraki 305-8577, Japan
| | - Akiko Fujimura
- Graduate School of Life and Environmental Sciences, 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
| | - Rina Udagawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tenno-dai, Tsukuba Science City, Ibaraki 305-8577, Japan
| | - Toru Hirota
- Division of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research, 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, Ibaraki 305-8577, Japan
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208
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Lindström MS, Jurada D, Bursac S, Orsolic I, Bartek J, Volarevic S. Nucleolus as an emerging hub in maintenance of genome stability and cancer pathogenesis. Oncogene 2018; 37:2351-2366. [PMID: 29429989 PMCID: PMC5931986 DOI: 10.1038/s41388-017-0121-z] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/15/2017] [Accepted: 11/15/2017] [Indexed: 12/13/2022]
Abstract
The nucleolus is the major site for synthesis of ribosomes, complex molecular machines that are responsible for protein synthesis. A wealth of research over the past 20 years has clearly indicated that both quantitative and qualitative alterations in ribosome biogenesis can drive the malignant phenotype via dysregulation of protein synthesis. However, numerous recent proteomic, genomic, and functional studies have implicated the nucleolus in the regulation of processes that are unrelated to ribosome biogenesis, including DNA-damage response, maintenance of genome stability and its spatial organization, epigenetic regulation, cell-cycle control, stress responses, senescence, global gene expression, as well as assembly or maturation of various ribonucleoprotein particles. In this review, the focus will be on features of rDNA genes, which make them highly vulnerable to DNA damage and intra- and interchromosomal recombination as well as built-in mechanisms that prevent and repair rDNA damage, and how dysregulation of this interplay affects genome-wide DNA stability, gene expression and the balance between euchromatin and heterochromatin. We will also present the most recent insights into how malfunction of these cellular processes may be a central driving force of human malignancies, and propose a promising new therapeutic approach for the treatment of cancer.
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Affiliation(s)
- Mikael S Lindström
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Deana Jurada
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia
| | - Sladana Bursac
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia
| | - Ines Orsolic
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia
| | - Jiri Bartek
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
- The Danish Cancer Society Research Centre, Copenhagen, Denmark.
| | - Sinisa Volarevic
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia.
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia.
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209
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Blewett NH, Maraia RJ. La involvement in tRNA and other RNA processing events including differences among yeast and other eukaryotes. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2018; 1861:361-372. [PMID: 29397330 DOI: 10.1016/j.bbagrm.2018.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/29/2017] [Accepted: 01/17/2018] [Indexed: 10/25/2022]
Abstract
The conserved nuclear RNA-binding factor known as La protein arose in an ancient eukaryote, phylogenetically associated with another eukaryotic hallmark, synthesis of tRNA by RNA polymerase III (RNAP III). Because 3'-oligo(U) is the sequence-specific signal for transcription termination by RNAP III as well as the high affinity binding site for La, the latter is linked to the intranuclear posttranscriptional processing of eukaryotic precursor-tRNAs. The pre-tRNA processing pathway must accommodate a variety of substrates that are destined for both common steps as well as tRNA-specific events. The order of intranuclear pre-tRNA processing steps is mediated in part by three activities derived from interaction with La protein: 3'-end protection from untimely decay by 3' exonucleases, nuclear retention and chaperone activity that helps prevent pre-tRNA misfolding and mischanneling into offline pathways. A focus of this perspective will be on differences between yeast and mammals in the subcellular partitioning of pre-tRNA intermediates and differential interactions with La. We review how this is most relevant to pre-tRNA splicing which occurs in the cytoplasm of yeasts but in nuclei of higher eukaryotes. Also divergent is La architecture, comprised of three RNA-binding domains in organisms in all examined branches of the eukaryal tree except yeast, which have lost the C-terminal RNA recognition motif-2α (RRM2α) domain. We also review emerging data that suggest mammalian La interacts with nuclear pre-tRNA splicing intermediates and may impact this branch of the tRNA maturation pathway. Finally, because La is involved in intranuclear tRNA biogenesis we review relevant aspects of tRNA-associated neurodegenerative diseases. This article is part of a Special Issue entitled: SI: Regulation of tRNA synthesis and modification in physiological conditions and disease edited by Dr. Boguta Magdalena.
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Affiliation(s)
- Nathan H Blewett
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Richard J Maraia
- Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA; Commissioned Corps, U.S. Public Health Service, Rockville, MD, USA.
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210
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Bennett AH, O’Donohue MF, Gundry SR, Chan AT, Widrick J, Draper I, Chakraborty A, Zhou Y, Zon LI, Gleizes PE, Beggs AH, Gupta VA. RNA helicase, DDX27 regulates skeletal muscle growth and regeneration by modulation of translational processes. PLoS Genet 2018. [PMID: 29518074 PMCID: PMC5843160 DOI: 10.1371/journal.pgen.1007226] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Gene expression in a tissue-specific context depends on the combined efforts of epigenetic, transcriptional and post-transcriptional processes that lead to the production of specific proteins that are important determinants of cellular identity. Ribosomes are a central component of the protein biosynthesis machinery in cells; however, their regulatory roles in the translational control of gene expression in skeletal muscle remain to be defined. In a genetic screen to identify critical regulators of myogenesis, we identified a DEAD-Box RNA helicase, DDX27, that is required for skeletal muscle growth and regeneration. We demonstrate that DDX27 regulates ribosomal RNA (rRNA) maturation, and thereby the ribosome biogenesis and the translation of specific transcripts during myogenesis. These findings provide insight into the translational regulation of gene expression in myogenesis and suggest novel functions for ribosomes in regulating gene expression in skeletal muscles.
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Affiliation(s)
- Alexis H. Bennett
- Division of Genetics, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marie-Francoise O’Donohue
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, UPS, CNRS, France
| | - Stacey R. Gundry
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Aye T. Chan
- Stem Cell Program and Pediatric Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeffrey Widrick
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, United States of America
| | - Anirban Chakraborty
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, UPS, CNRS, France
- Division of Molecular Genetics and Cancer, NU Centre for Science Education and Research, Nitte University, Mangalore, India
| | - Yi Zhou
- Stem Cell Program and Pediatric Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Leonard I. Zon
- Stem Cell Program and Pediatric Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Pierre-Emmanuel Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, UPS, CNRS, France
| | - Alan H. Beggs
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Vandana A. Gupta
- Division of Genetics, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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211
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Schuller JM, Falk S, Fromm L, Hurt E, Conti E. Structure of the nuclear exosome captured on a maturing preribosome. Science 2018. [PMID: 29519915 DOI: 10.1126/science.aar5428] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The RNA exosome complex processes and degrades a wide range of transcripts, including ribosomal RNAs (rRNAs). We used cryo-electron microscopy to visualize the yeast nuclear exosome holocomplex captured on a precursor large ribosomal subunit (pre-60S) during 7S-to-5.8S rRNA processing. The cofactors of the nuclear exosome are sandwiched between the ribonuclease core complex (Exo-10) and the remodeled "foot" structure of the pre-60S particle, which harbors the 5.8S rRNA precursor. The exosome-associated helicase Mtr4 recognizes the preribosomal substrate by docking to specific sites on the 25S rRNA, captures the 3' extension of the 5.8S rRNA, and channels it toward Exo-10. The structure elucidates how the exosome forms a structural and functional unit together with its massive pre-60S substrate to process rRNA during ribosome maturation.
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Affiliation(s)
- Jan Michael Schuller
- Department of Structural Cell Biology, Max Planck Institute (MPI) for Biochemistry, Munich, Germany
| | - Sebastian Falk
- Department of Structural Cell Biology, Max Planck Institute (MPI) for Biochemistry, Munich, Germany
| | - Lisa Fromm
- Biochemistry Centre, University of Heidelberg, Heidelberg, Germany
| | - Ed Hurt
- Biochemistry Centre, University of Heidelberg, Heidelberg, Germany.
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute (MPI) for Biochemistry, Munich, Germany.
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212
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Pellegrino S, Meyer M, Zorbas C, Bouchta SA, Saraf K, Pelly SC, Yusupova G, Evidente A, Mathieu V, Kornienko A, Lafontaine DLJ, Yusupov M. The Amaryllidaceae Alkaloid Haemanthamine Binds the Eukaryotic Ribosome to Repress Cancer Cell Growth. Structure 2018; 26:416-425.e4. [PMID: 29429877 DOI: 10.1016/j.str.2018.01.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/01/2017] [Accepted: 01/12/2018] [Indexed: 01/05/2023]
Abstract
Alkaloids isolated from the Amaryllidaceae plants have potential as therapeutics for treating human diseases. Haemanthamine has been studied as a novel anticancer agent due to its ability to overcome cancer cell resistance to apoptosis. Biochemical experiments have suggested that hemanthamine targets the ribosome. However, a structural characterization of its mechanism has been missing. Here we present the 3.1 Å resolution X-ray structure of haemanthamine bound to the Saccharomyces cerevisiae 80S ribosome. This structure reveals that haemanthamine targets the A-site cleft on the large ribosomal subunit rearranging rRNA to halt the elongation phase of translation. Furthermore, we provide evidence that haemanthamine and other Amaryllidaceae alkaloids also inhibit specifically ribosome biogenesis, triggering nucleolar stress response and leading to p53 stabilization in cancer cells. Together with a computer-aided interpretation of existing structure-activity relationships of Amaryllidaceae alkaloids congeners, we provide a rationale for designing molecules with enhanced potencies and reduced toxicities.
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Affiliation(s)
- Simone Pellegrino
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, 67404 Illkirch, France
| | - Mélanie Meyer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, 67404 Illkirch, France
| | - Christiane Zorbas
- RNA Molecular Biology and Center for Microscopy and Molecular Imaging (CMMI), Fonds National de la Recherche (F.R.S./FNRS) and Université Libre de Bruxelles (ULB), BioPark Campus, 6041 Gosselies, Belgium
| | - Soumaya A Bouchta
- RNA Molecular Biology and Center for Microscopy and Molecular Imaging (CMMI), Fonds National de la Recherche (F.R.S./FNRS) and Université Libre de Bruxelles (ULB), BioPark Campus, 6041 Gosselies, Belgium
| | - Kritika Saraf
- RNA Molecular Biology and Center for Microscopy and Molecular Imaging (CMMI), Fonds National de la Recherche (F.R.S./FNRS) and Université Libre de Bruxelles (ULB), BioPark Campus, 6041 Gosselies, Belgium
| | - Stephen C Pelly
- Department of Chemistry and Polymer Science, Stellenbosch University, Stellenbosch, Matieland 7602, South Africa
| | - Gulnara Yusupova
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, 67404 Illkirch, France
| | - Antonio Evidente
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant'Angelo, Via Cintia 4, 80126 Napoli, Italy
| | - Véronique Mathieu
- Laboratoire de Cancérologie et de Toxicologie Expérimentale, Faculté de Pharmacie, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Alexander Kornienko
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Denis L J Lafontaine
- RNA Molecular Biology and Center for Microscopy and Molecular Imaging (CMMI), Fonds National de la Recherche (F.R.S./FNRS) and Université Libre de Bruxelles (ULB), BioPark Campus, 6041 Gosselies, Belgium.
| | - Marat Yusupov
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, 67404 Illkirch, France.
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213
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Bustelo XR, Dosil M. Ribosome biogenesis and cancer: basic and translational challenges. Curr Opin Genet Dev 2018; 48:22-29. [DOI: 10.1016/j.gde.2017.10.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/13/2017] [Accepted: 10/02/2017] [Indexed: 01/08/2023]
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214
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Langhendries JL, Nicolas E, Doumont G, Goldman S, Lafontaine DLJ. The human box C/D snoRNAs U3 and U8 are required for pre-rRNA processing and tumorigenesis. Oncotarget 2018; 7:59519-59534. [PMID: 27517747 PMCID: PMC5312328 DOI: 10.18632/oncotarget.11148] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/30/2016] [Indexed: 01/05/2023] Open
Abstract
Small nucleolar RNAs (snoRNAs) are emerging as a novel class of proto-oncogenes and tumor suppressors; their involvement in tumorigenesis remains unclear. The box C/D snoRNAs U3 and U8 are upregulated in breast cancers. Here we characterize the function of human U3 and U8 in ribosome biogenesis, nucleolar structure, and tumorigenesis. We show in breast (MCF-7) and lung (H1944) cancer cells that U3 and U8 are required for pre-rRNA processing reactions leading, respectively, to synthesis of the small and large ribosomal subunits. U3 or U8 depletion triggers a remarkably potent p53-dependent anti-tumor stress response involving the ribosomal proteins uL5 (RPL11) and uL18 (RPL5). Interestingly, the nucleolar structure is more sensitive to perturbations in lung cancer than in breast cancer cells. We reveal in a mouse xenograft model that the tumorigenic potential of cancer cells is reduced in the case of U3 suppression and totally abolished upon U8 depletion. Tumors derived from U3-knockdown cells displayed markedly lower metabolic volume and activity than tumors derived from aggressive control cancer cells. Unexpectedly, metabolic tracer uptake by U3-suppressed tumors appeared more heterogeneous, indicating distinctive tumor growth properties that may reflect non-conventional regulatory functions of U3 (or fragments derived from it) in mRNA metabolism.
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Affiliation(s)
- Jean-Louis Langhendries
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S.-FNRS), Université Libre de Bruxelles (ULB), BioPark Campus, Gosselies, Belgium
| | - Emilien Nicolas
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S.-FNRS), Université Libre de Bruxelles (ULB), BioPark Campus, Gosselies, Belgium
| | - Gilles Doumont
- Center for Microscopy and Molecular Imaging (CMMI), BioPark campus, Université Libre de Bruxelles, Belgium
| | - Serge Goldman
- Nuclear Medecine, Erasme Hospital, Université Libre de Bruxelles, Belgium.,Center for Microscopy and Molecular Imaging (CMMI), BioPark campus, Université Libre de Bruxelles, Belgium
| | - Denis L J Lafontaine
- RNA Molecular Biology, Fonds de la Recherche Scientifique (F.R.S.-FNRS), Université Libre de Bruxelles (ULB), BioPark Campus, Gosselies, Belgium.,Center for Microscopy and Molecular Imaging (CMMI), BioPark campus, Université Libre de Bruxelles, Belgium
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215
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Kojima K, Tamura J, Chiba H, Fukada K, Tsukaya H, Horiguchi G. Two Nucleolar Proteins, GDP1 and OLI2, Function As Ribosome Biogenesis Factors and Are Preferentially Involved in Promotion of Leaf Cell Proliferation without Strongly Affecting Leaf Adaxial-Abaxial Patterning in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2018; 8:2240. [PMID: 29375609 PMCID: PMC5767255 DOI: 10.3389/fpls.2017.02240] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/20/2017] [Indexed: 05/25/2023]
Abstract
Leaf abaxial-adaxial patterning is dependent on the mutual repression of leaf polarity genes expressed either adaxially or abaxially. In Arabidopsis thaliana, this process is strongly affected by mutations in ribosomal protein genes and in ribosome biogenesis genes in a sensitized genetic background, such as asymmetric leaves2 (as2). Most ribosome-related mutants by themselves do not show leaf abaxialization, and one of their typical phenotypes is the formation of pointed rather than rounded leaves. In this study, we characterized two ribosome-related mutants to understand how ribosome biogenesis is linked to several aspects of leaf development. Previously, we isolated oligocellula2 (oli2) which exhibits the pointed-leaf phenotype and has a cell proliferation defect. OLI2 encodes a homolog of Nop2 in Saccharomyces cerevisiae, a ribosome biogenesis factor involved in pre-60S subunit maturation. In this study, we found another pointed-leaf mutant that carries a mutation in a gene encoding an uncharacterized protein with a G-patch domain. Similar to oli2, this mutant, named g-patch domain protein1 (gdp1), has a reduced number of leaf cells. In addition, gdp1 oli2 double mutants showed a strong genetic interaction such that they synergistically impaired cell proliferation in leaves and produced markedly larger cells. On the other hand, they showed additive phenotypes when combined with several known ribosomal protein mutants. Furthermore, these mutants have a defect in pre-rRNA processing. GDP1 and OLI2 are strongly expressed in tissues with high cell proliferation activity, and GDP1-GFP and GFP-OLI2 are localized in the nucleolus. These results suggest that OLI2 and GDP1 are involved in ribosome biogenesis. We then examined the effects of gdp1 and oli2 on adaxial-abaxial patterning by crossing them with as2. Interestingly, neither gdp1 nor oli2 strongly enhanced the leaf polarity defect of as2. Similar results were obtained with as2 gdp1 oli2 triple mutants although they showed severe growth defects. These results suggest that the leaf abaxialization phenotype induced by ribosome-related mutations is not merely the result of a general growth defect and that there may be a sensitive process in the ribosome biogenesis pathway that affects adaxial-abaxial patterning when compromised by a mutation.
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Affiliation(s)
- Koji Kojima
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Junya Tamura
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Hiroto Chiba
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Kanae Fukada
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Hirokazu Tsukaya
- Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Okazaki Institute for Integrative Bioscience, Okazaki, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Tokyo, Japan
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216
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Abstract
The ribosome is a complex molecular machine composed of numerous distinct proteins and nucleic acids and is responsible for protein synthesis in every living cell. Ribosome biogenesis is one of the most multifaceted and energy- demanding processes in biology, involving a large number of assembly and maturation factors, the functions of which are orchestrated by multiple cellular inputs, including mitogenic signals and nutrient availability. Although causal associations between inherited mutations affecting ribosome biogenesis and elevated cancer risk have been established over the past decade, mechanistic data have emerged suggesting a broader role for dysregulated ribosome biogenesis in the development and progression of most spontaneous cancers. In this Opinion article, we highlight the most recent findings that provide new insights into the molecular basis of ribosome biogenesis in cancer and offer our perspective on how these observations present opportunities for the design of new targeted cancer treatments.
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Affiliation(s)
- Joffrey Pelletier
- Laboratory of Cancer Metabolism, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, 08908 L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain
| | - George Thomas
- Laboratory of Cancer Metabolism, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Duran i Reynals, 08908 L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain; at the Division of Hematology and Oncology, Department of Internal Medicine, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, USA; and at the Unit of Biochemistry, Department of Physiological Sciences II, Faculty of Medicine, Campus Universitari de Bellvitge, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), University of Barcelona, 08908 L'Hospitalet de Llobregat, Barcelona, Catalonia, Spain
| | - Siniša Volarević
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia; and at the Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Brace Branchetta 20, 51000 Rijeka, Croatia
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217
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Liu Y, Imai R. Function of Plant DExD/H-Box RNA Helicases Associated with Ribosomal RNA Biogenesis. FRONTIERS IN PLANT SCIENCE 2018; 9:125. [PMID: 29472942 PMCID: PMC5809497 DOI: 10.3389/fpls.2018.00125] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/23/2018] [Indexed: 05/18/2023]
Abstract
Ribosome biogenesis is a highly complex process that requires several cofactors, including DExD/H-box RNA helicases (RHs). RHs are a family of ATPases that rearrange the secondary structures of RNA and thus remodel ribonucleoprotein complexes. DExD/H-box RHs are found in most organisms and play critical roles in a variety of RNA-involved cellular events. In human and yeast cells, many DExD/H box RHs participate in multiple steps of ribosome biogenesis and regulate cellular proliferation and stress responses. In plants, several DExD/H-box RHs have been demonstrated to be associated with plant development and abiotic stress tolerance through their functions in modulating pre-rRNA processing. In this review, we summarize the pleiotropic roles of DExD/H-box RHs in rRNA biogenesis and other biological functions. We also describe the overall function of the DExD/H-box RH family in ribosome biogenesis based on data from human and yeast.
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218
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Umbaugh CS, Diaz-Quiñones A, Neto MF, Shearer JJ, Figueiredo ML. A dock derived compound against laminin receptor (37 LR) exhibits anti-cancer properties in a prostate cancer cell line model. Oncotarget 2017; 9:5958-5978. [PMID: 29464047 PMCID: PMC5814187 DOI: 10.18632/oncotarget.23236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/16/2017] [Indexed: 11/25/2022] Open
Abstract
Laminin receptor (67 LR) is a 67 kDa protein derived from a 37 kDa precursor (37 LR). 37/67 LR is a strong clinical correlate for progression, aggression, and chemotherapeutic relapse of several cancers including breast, prostate, and colon. The ability of 37/67 LR to promote cancer cell aggressiveness is further increased by its ability to transduce physiochemical and mechanosensing signals in endothelial cells and modulate angiogenesis. Recently, it was demonstrated that 37/67 LR modulates the anti-angiogenic potential of the secreted glycoprotein pigment epithelium-derived factor (PEDF). Restoration of PEDF balance is a desirable therapeutic outcome, and we sought to identify a small molecule that could recapitulate known signaling properties of PEDF but without the additional complications of peptide formulation or gene delivery safety validation. We used an in silico drug discovery approach to target the interaction interface between PEDF and 37 LR. Following cell based counter screening and binding validation, we characterized a hit compound's anti-viability, activation of PEDF signaling-related genes, anti-wound healing, and anti-cancer signaling properties. This hit compound has potential for future development as a lead compound for treating tumor growth and inhibiting angiogenesis.
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Affiliation(s)
- Charles Samuel Umbaugh
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Adriana Diaz-Quiñones
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Manoel Figueiredo Neto
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Joseph J Shearer
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Marxa L Figueiredo
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
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219
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Scott DD, Trahan C, Zindy PJ, Aguilar LC, Delubac MY, Van Nostrand EL, Adivarahan S, Wei KE, Yeo GW, Zenklusen D, Oeffinger M. Nol12 is a multifunctional RNA binding protein at the nexus of RNA and DNA metabolism. Nucleic Acids Res 2017; 45:12509-12528. [PMID: 29069457 PMCID: PMC5716212 DOI: 10.1093/nar/gkx963] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 10/01/2017] [Accepted: 10/09/2017] [Indexed: 12/29/2022] Open
Abstract
To counteract the breakdown of genome integrity, eukaryotic cells have developed a network of surveillance pathways to prevent and resolve DNA damage. Recent data has recognized the importance of RNA binding proteins (RBPs) in DNA damage repair (DDR) pathways. Here, we describe Nol12 as a multifunctional RBP with roles in RNA metabolism and genome maintenance. Nol12 is found in different subcellular compartments-nucleoli, where it associates with ribosomal RNA and is required for efficient separation of large and small subunit precursors at site 2; the nucleoplasm, where it co-localizes with the RNA/DNA helicase Dhx9 and paraspeckles; as well as GW/P-bodies in the cytoplasm. Loss of Nol12 results in the inability of cells to recover from DNA stress and a rapid p53-independent ATR-Chk1-mediated apoptotic response. Nol12 co-localizes with DNA repair proteins in vivo including Dhx9, as well as with TOPBP1 at sites of replication stalls, suggesting a role for Nol12 in the resolution of DNA stress and maintenance of genome integrity. Identification of a complex Nol12 interactome, which includes NONO, Dhx9, DNA-PK and Stau1, further supports the protein's diverse functions in RNA metabolism and DNA maintenance, establishing Nol12 as a multifunctional RBP essential for genome integrity.
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Affiliation(s)
- Daniel D. Scott
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec H3A 1A3, Canada
| | - Christian Trahan
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Pierre J. Zindy
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
| | - Lisbeth C. Aguilar
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
| | - Marc Y. Delubac
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Eric L. Van Nostrand
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Srivathsan Adivarahan
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Karen E. Wei
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
| | - Gene W. Yeo
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Molecular Engineering Laboratory, A*STAR, Singapore
| | - Daniel Zenklusen
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Marlene Oeffinger
- Institut de Recherches Cliniques de Montréal, 110 Avenue des Pins Ouest, Montréal, Québec H2W 1R7, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec H3A 1A3, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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220
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Tchelidze P, Benassarou A, Kaplan H, O’Donohue MF, Lucas L, Terryn C, Rusishvili L, Mosidze G, Lalun N, Ploton D. Nucleolar sub-compartments in motion during rRNA synthesis inhibition: Contraction of nucleolar condensed chromatin and gathering of fibrillar centers are concomitant. PLoS One 2017; 12:e0187977. [PMID: 29190286 PMCID: PMC5708645 DOI: 10.1371/journal.pone.0187977] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 10/30/2017] [Indexed: 12/26/2022] Open
Abstract
The nucleolus produces the large polycistronic transcript (47S precursor) containing the 18S, 5.8S and 28S rRNA sequences and hosts most of the nuclear steps of pre-rRNA processing. Among numerous components it contains condensed chromatin and active rRNA genes which adopt a more accessible conformation. For this reason, it is a paradigm of chromosome territory organization. Active rRNA genes are clustered within several fibrillar centers (FCs), in which they are maintained in an open configuration by Upstream Binding Factor (UBF) molecules. Here, we used the reproducible reorganization of nucleolar components induced by the inhibition of rRNA synthesis by Actinomycin D (AMD) to address the steps of the spatiotemporal reorganization of FCs and nucleolar condensed chromatin. To reach that goal, we used two complementary approaches: i) time-lapse confocal imaging of cells expressing one or several GFP-tagged proteins (fibrillarin, UBF, histone H2B) and ii) ultrastructural identification of nucleolar components involved in the reorganization. Data obtained by time lapse confocal microscopy were analyzed through detailed 3D imaging. This allowed us to demonstrate that AMD treatment induces no fusion and no change in the relative position of the different nucleoli contained in one nucleus. In contrast, for each nucleolus, we observed step by step gathering and fusion of both FCs and nucleolar condensed chromatin. To analyze the reorganization of FCs and condensed chromatin at a higher resolution, we performed correlative light and electron microscopy electron microscopy (CLEM) imaging of the same cells. We demonstrated that threads of intranucleolar condensed chromatin are localized in a complex 3D network of vacuoles. Upon AMD treatment, these structures coalesce before migrating toward the perinucleolar condensed chromatin, to which they finally fuse. During their migration, FCs, which are all linked to ICC, are pulled by the latter to gather as caps disposed at the periphery of nucleoli.
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Affiliation(s)
- Pavel Tchelidze
- Faculty of Exact and Life Sciences, Department of Morphology, Tbilisi State University, Tbilisi, Georgia
| | - Aassif Benassarou
- EA 3804 (CRESTIC), Université de Reims Champagne Ardenne, Reims, France
| | - Hervé Kaplan
- Université de Reims Champagne Ardenne, Reims, France
| | - Marie-Françoise O’Donohue
- Laboratoire de Biologie Moléculaire Eukaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Laurent Lucas
- EA 3804 (CRESTIC), Université de Reims Champagne Ardenne, Reims, France
| | - Christine Terryn
- Platform of Cellular and Tissular Imaging (PICT), Université de Reims Champagne Ardenne, Reims, France
| | - Levan Rusishvili
- Faculty of Exact and Life Sciences, Department of Morphology, Tbilisi State University, Tbilisi, Georgia
| | - Giorgi Mosidze
- Faculty of Exact and Life Sciences, Department of Morphology, Tbilisi State University, Tbilisi, Georgia
| | - Nathalie Lalun
- CNRS UMR 7369, Université de Reims Champagne Ardenne, Reims, France
| | - Dominique Ploton
- CNRS UMR 7369, Université de Reims Champagne Ardenne, Reims, France
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221
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Montellese C, Montel-Lehry N, Henras AK, Kutay U, Gleizes PE, O'Donohue MF. Poly(A)-specific ribonuclease is a nuclear ribosome biogenesis factor involved in human 18S rRNA maturation. Nucleic Acids Res 2017; 45:6822-6836. [PMID: 28402503 PMCID: PMC5499762 DOI: 10.1093/nar/gkx253] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/03/2017] [Indexed: 01/28/2023] Open
Abstract
The poly-A specific ribonuclease (PARN), initially characterized for its role in mRNA catabolism, supports the processing of different types of non-coding RNAs including telomerase RNA. Mutations in PARN are linked to dyskeratosis congenita and pulmonary fibrosis. Here, we show that PARN is part of the enzymatic machinery that matures the human 18S ribosomal RNA (rRNA). Consistent with its nucleolar steady-state localization, PARN is required for 40S ribosomal subunit production and co-purifies with 40S subunit precursors. Depletion of PARN or expression of a catalytically-compromised PARN mutant results in accumulation of 3΄ extended 18S rRNA precursors. Analysis of these processing intermediates reveals a defect in 3΄ to 5΄ trimming of the internal transcribed spacer 1 (ITS1) region, subsequent to endonucleolytic cleavage at site E. Consistent with a function of PARN in exonucleolytic trimming of 18S-E pre-rRNA, recombinant PARN can process the corresponding ITS1 RNA fragment in vitro. Trimming of 18S-E pre-rRNA by PARN occurs in the nucleus, upstream of the final endonucleolytic cleavage by the endonuclease NOB1 in the cytoplasm. These results identify PARN as a new component of the ribosome biogenesis machinery in human cells. Defects in ribosome biogenesis could therefore underlie the pathologies linked to mutations in PARN.
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Affiliation(s)
| | - Nathalie Montel-Lehry
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Anthony K Henras
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Ulrike Kutay
- Institut für Biochemie, ETH Zurich, Zurich CH-8093, Switzerland
| | - Pierre-Emmanuel Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
| | - Marie-Françoise O'Donohue
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France
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222
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Shen W, Sun H, De Hoyos CL, Bailey JK, Liang XH, Crooke ST. Dynamic nucleoplasmic and nucleolar localization of mammalian RNase H1 in response to RNAP I transcriptional R-loops. Nucleic Acids Res 2017; 45:10672-10692. [PMID: 28977560 PMCID: PMC5737507 DOI: 10.1093/nar/gkx710] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 08/04/2017] [Indexed: 12/29/2022] Open
Abstract
An R-loop is a DNA:RNA hybrid formed during transcription when a DNA duplex is invaded by a nascent RNA transcript. R-loops accumulate in nucleoli during RNA polymerase I (RNAP I) transcription. Here, we report that mammalian RNase H1 enriches in nucleoli and co-localizes with R-loops in cultured human cells. Co-migration of RNase H1 and R-loops from nucleoli to perinucleolar ring structures was observed upon inhibition of RNAP I transcription. Treatment with camptothecin which transiently stabilized nucleolar R-loops recruited RNase H1 to the nucleoli. It has been reported that the absence of Topoisomerase and RNase H activity in Escherichia coli or Saccharomyces cerevisiae caused R-loop accumulation along rDNA. We found that the distribution of RNase H1 and Top1 along rDNA coincided at sites where R-loops accumulated in mammalian cells. Loss of either RNase H1 or Top1 caused R-loop accumulation, and the accumulation of R-loops was exacerbated when both proteins were depleted. Importantly, we observed that protein levels of Top1 were negatively correlated with the abundance of RNase H1. We conclude that Top1 and RNase H1 are partially functionally redundant in mammalian cells to suppress RNAP I transcription-associate R-loops.
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Affiliation(s)
- Wen Shen
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Hong Sun
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Cheryl L De Hoyos
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Jeffrey K Bailey
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Xue-Hai Liang
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Stanley T Crooke
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc., 2855 Gazelle Court, Carlsbad, CA 92010, USA
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223
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Cheng J, Kellner N, Berninghausen O, Hurt E, Beckmann R. 3.2-Å-resolution structure of the 90S preribosome before A1 pre-rRNA cleavage. Nat Struct Mol Biol 2017; 24:954-964. [PMID: 28967883 DOI: 10.1038/nsmb.3476] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/04/2017] [Indexed: 12/15/2022]
Abstract
The 40S small ribosomal subunit is cotranscriptionally assembled in the nucleolus as part of a large chaperone complex called the 90S preribosome or small-subunit processome. Here, we present the 3.2-Å-resolution structure of the Chaetomium thermophilum 90S preribosome, which allowed us to build atomic structures for 34 assembly factors, including the Mpp10 complex, Bms1, Utp14 and Utp18, and the complete U3 small nucleolar ribonucleoprotein. Moreover, we visualized the U3 RNA heteroduplexes with a 5' external transcribed spacer (5' ETS) and pre-18S RNA, and their stabilization by 90S factors. Overall, the structure explains how a highly intertwined network of assembly factors and pre-rRNA guide the sequential, independent folding of the individual pre-40S domains while the RNA regions forming the 40S active sites are kept immature. Finally, by identifying the unprocessed A1 cleavage site and the nearby Utp24 endonuclease, we suggest a proofreading model for regulated 5'-ETS separation and 90S-pre-40S transition.
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Affiliation(s)
- Jingdong Cheng
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany
| | - Nikola Kellner
- Biochemie-Zentrum der Universität Heidelberg, Heidelberg, Germany
| | - Otto Berninghausen
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany
| | - Ed Hurt
- Biochemie-Zentrum der Universität Heidelberg, Heidelberg, Germany
| | - Roland Beckmann
- Gene Center Munich and Center of Integrated Protein Science-Munich (CiPS-M), Department of Biochemistry, University of Munich, Munich, Germany
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224
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Pillon MC, Stanley RE. Nuclease integrated kinase super assemblies (NiKs) and their role in RNA processing. Curr Genet 2017; 64:183-190. [PMID: 28929238 DOI: 10.1007/s00294-017-0749-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/24/2023]
Abstract
Here we highlight the Grc3/Las1 complex, an essential RNA processing machine that is well conserved across eukaryotes and required for processing the pre-ribosomal RNA (pre-rRNA). Las1 is an endoribonuclease that cleaves the pre-rRNA while Grc3 is a polynucleotide kinase that phosphorylates the Las1-cleaved RNA product. Recently we showed that Grc3 and Las1 assemble into a higher-order complex composed of a dimer of Grc3/Las1 heterodimers that is required for nuclease and kinase activity. Unexpectedly, we found that the Grc3/Las1 complex draws numerous parallels with two other eukaryotic nucleases, Ire1 and RNase L. In this perspective we explore the similarities and differences between this family of nuclease integrated kinase super assemblies (NiKs) and their distinct roles in RNA cleavage.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
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225
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Memet I, Doebele C, Sloan KE, Bohnsack MT. The G-patch protein NF-κB-repressing factor mediates the recruitment of the exonuclease XRN2 and activation of the RNA helicase DHX15 in human ribosome biogenesis. Nucleic Acids Res 2017; 45:5359-5374. [PMID: 28115624 PMCID: PMC5435916 DOI: 10.1093/nar/gkx013] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/04/2017] [Indexed: 01/05/2023] Open
Abstract
In eukaryotes, the synthesis of ribosomal subunits, which involves the maturation of the ribosomal (r)RNAs and assembly of ribosomal proteins, requires the co-ordinated action of a plethora of ribosome biogenesis factors. Many of these cofactors remain to be characterized in human cells. Here, we demonstrate that the human G-patch protein NF-κB-repressing factor (NKRF) forms a pre-ribosomal subcomplex with the DEAH-box RNA helicase DHX15 and the 5΄-3΄ exonuclease XRN2. Using UV crosslinking and analysis of cDNA (CRAC), we reveal that NKRF binds to the transcribed spacer regions of the pre-rRNA transcript. Consistent with this, we find that depletion of NKRF, XRN2 or DHX15 impairs an early pre-rRNA cleavage step (A’). The catalytic activity of DHX15, which we demonstrate is stimulated by NKRF functioning as a cofactor, is required for efficient A’ cleavage, suggesting that a structural remodelling event may facilitate processing at this site. In addition, we show that depletion of NKRF or XRN2 also leads to the accumulation of excised pre-rRNA spacer fragments and that NKRF is essential for recruitment of the exonuclease to nucleolar pre-ribosomal complexes. Our findings therefore reveal a novel pre-ribosomal subcomplex that plays distinct roles in the processing of pre-rRNAs and the turnover of excised spacer fragments.
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Affiliation(s)
- Indira Memet
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany
| | - Carmen Doebele
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany
| | - Katherine E Sloan
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany
| | - Markus T Bohnsack
- Institute for Molecular Biology, University Medical Center Göttingen, Georg-August-University, 37073 Göttingen, Germany.,Göttingen Centre for Molecular Biosciences, Georg-August-University, 37073 Göttingen, Germany
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226
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Identification of sites of 2'-O-methylation vulnerability in human ribosomal RNAs by systematic mapping. Sci Rep 2017; 7:11490. [PMID: 28904332 PMCID: PMC5597630 DOI: 10.1038/s41598-017-09734-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 07/28/2017] [Indexed: 12/18/2022] Open
Abstract
Ribosomal RNA modifications are important in optimizing ribosome function. Sugar 2'-O-methylation performed by fibrillarin-associated box C/D antisense guide snoRNAs impacts all steps of translation, playing a role in disease etiology (cancer). As it renders adjacent phosphodiester bonds resistant to alkaline treatment, 2'-O-methylation can be monitored qualitatively and quantitatively by applying next-generation sequencing to fragments of randomly cleaved RNA. We remapped all sites of 2'-O-methylation in human rRNAs in two isogenic diploid cell lines, one producing and one not producing the antitumor protein p53. We identified sites naturally modified only partially (confirming the existence in cells of compositionally distinct ribosomes with potentially specialized functions) and sites whose 2'-O-methylation is sensitive to p53. We mapped sites particularly vulnerable to a reduced level of the methyltransferase fibrillarin. The remarkable fact that these are largely sites of natural hypomodification provides initial insights into the mechanism of partial RNA modification. Sites where methylation appeared vulnerable lie peripherally on the 3-D structure of the ribosomal subunits, whereas the numerous modifications present at the core of the subunits, where the functional centers lie, appeared robustly made. We suggest that vulnerable sites of 2'-O-methylation are highly likely to undergo specific regulation during normal and pathological processes.
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227
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Wells GR, Weichmann F, Sloan KE, Colvin D, Watkins NJ, Schneider C. The ribosome biogenesis factor yUtp23/hUTP23 coordinates key interactions in the yeast and human pre-40S particle and hUTP23 contains an essential PIN domain. Nucleic Acids Res 2017; 45:4796-4809. [PMID: 28082392 PMCID: PMC5416842 DOI: 10.1093/nar/gkw1344] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/22/2016] [Indexed: 11/30/2022] Open
Abstract
Two proteins with PIN endonuclease domains, yUtp24(Fcf1)/hUTP24 and yUtp23/hUTP23 are essential for early pre-ribosomal (r)RNA cleavages at sites A0, A1/1 and A2/2a in yeast and humans. The yUtp24/hUTP24 PIN endonuclease is proposed to cleave at sites A1/1 and A2/2a, but the enzyme cleaving at site A0 is not known. Yeast yUtp23 contains a degenerate, non-essential PIN domain and functions together with the snR30 snoRNA, while human hUTP23 is associated with U17, the human snR30 counterpart. Using in vivo RNA–protein crosslinking and gel shift experiments, we reveal that yUtp23/hUTP23 makes direct contacts with expansion sequence 6 (ES6) in the 18S rRNA sequence and that yUtp23 interacts with the 3΄ half of the snR30 snoRNA. Protein–protein interaction studies further demonstrated that yeast yUtp23 and human hUTP23 directly interact with the H/ACA snoRNP protein yNhp2/hNHP2, the RNA helicase yRok1/hROK1(DDX52), the ribosome biogenesis factor yRrp7/hRRP7 and yUtp24/hUTP24. yUtp23/hUTP23 could therefore be central to the coordinated integration and release of ES6 binding factors and likely plays a pivotal role in remodeling this pre-rRNA region in both yeast and humans. Finally, studies using RNAi-rescue systems in human cells revealed that intact PIN domain and Zinc finger motifs in human hUTP23 are essential for 18S rRNA maturation.
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Affiliation(s)
- Graeme R Wells
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Franziska Weichmann
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Katherine E Sloan
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - David Colvin
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Nicholas J Watkins
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Claudia Schneider
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
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228
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The AAA ATPase MDN1 Acts as a SUMO-Targeted Regulator in Mammalian Pre-ribosome Remodeling. Mol Cell 2017; 64:607-615. [PMID: 27814492 DOI: 10.1016/j.molcel.2016.09.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/26/2016] [Accepted: 09/28/2016] [Indexed: 01/03/2023]
Abstract
Biogenesis of translation-competent 80S ribosomes is a multi-step process requiring the sequential action of non-ribosomal trans-acting factors. We previously identified the human PELP1-TEX10-WDR18 complex and the associated SUMO isopeptidase SENP3 as regulators of 60S maturation. We provided evidence that deconjugating SUMO from PELP1 by SENP3 is instrumental for proper ribosome biogenesis. Here we show that SUMO conjugation/deconjugation of PELP1 controls its dynamic association with the AAA ATPase MDN1, a key factor of pre-60S remodeling. We demonstrate that modification of PELP1 promotes the recruitment of MDN1 to pre-60S particles, while deSUMOylation is needed to release both MDN1 and PELP1 from pre-ribosomes. Inactivation of SENP3 traps MDN1 at pre-60S particles and prevents critical remodeling events, ultimately generating aberrant pre-60S complexes. We define MDN1 as a SUMO-targeted AAA ATPase, and we propose that a controlled SUMO cycle on PELP1 serves as regulatory point for mammalian 60S maturation through ordered recruitment and release of MDN1.
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229
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Buchwalter A, Hetzer MW. Nucleolar expansion and elevated protein translation in premature aging. Nat Commun 2017; 8:328. [PMID: 28855503 PMCID: PMC5577202 DOI: 10.1038/s41467-017-00322-z] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 06/22/2017] [Indexed: 01/08/2023] Open
Abstract
Premature aging disorders provide an opportunity to study the mechanisms that drive aging. In Hutchinson-Gilford progeria syndrome (HGPS), a mutant form of the nuclear scaffold protein lamin A distorts nuclei and sequesters nuclear proteins. We sought to investigate protein homeostasis in this disease. Here, we report a widespread increase in protein turnover in HGPS-derived cells compared to normal cells. We determine that global protein synthesis is elevated as a consequence of activated nucleoli and enhanced ribosome biogenesis in HGPS-derived fibroblasts. Depleting normal lamin A or inducing mutant lamin A expression are each sufficient to drive nucleolar expansion. We further show that nucleolar size correlates with donor age in primary fibroblasts derived from healthy individuals and that ribosomal RNA production increases with age, indicating that nucleolar size and activity can serve as aging biomarkers. While limiting ribosome biogenesis extends lifespan in several systems, we show that increased ribosome biogenesis and activity are a hallmark of premature aging. HGPS is a premature aging disease caused by mutations in the nuclear protein lamin A. Here, the authors show that cells from patients with HGPS have expanded nucleoli and increased protein synthesis, and report that nucleoli also expand as aging progresses in cells derived from healthy individuals.
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Affiliation(s)
- Abigail Buchwalter
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Martin W Hetzer
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA, 92037, USA.
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230
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Sapio RT, Nezdyur AN, Krevetski M, Anikin L, Manna VJ, Minkovsky N, Pestov DG. Inhibition of post-transcriptional steps in ribosome biogenesis confers cytoprotection against chemotherapeutic agents in a p53-dependent manner. Sci Rep 2017; 7:9041. [PMID: 28831158 PMCID: PMC5567254 DOI: 10.1038/s41598-017-09002-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/17/2017] [Indexed: 12/11/2022] Open
Abstract
The p53-mediated nucleolar stress response associated with inhibition of ribosomal RNA transcription was previously shown to potentiate killing of tumor cells. Here, we asked whether targeting of ribosome biogenesis can be used as the basis for selective p53-dependent cytoprotection of nonmalignant cells. Temporary functional inactivation of the 60S ribosome assembly factor Bop1 in a 3T3 cell model markedly increased cell recovery after exposure to camptothecin or methotrexate. This was due, at least in part, to reversible pausing of the cell cycle preventing S phase associated DNA damage. Similar cytoprotective effects were observed after transient shRNA-mediated silencing of Rps19, but not several other tested ribosomal proteins, indicating distinct cellular responses to the inhibition of different steps in ribosome biogenesis. By temporarily inactivating Bop1 function, we further demonstrate selective killing of p53-deficient cells with camptothecin while sparing isogenic p53-positive cells. Thus, combining cytotoxic treatments with inhibition of select post-transcriptional steps of ribosome biogenesis holds potential for therapeutic targeting of cells that have lost p53.
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Affiliation(s)
- Russell T Sapio
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA.,Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA
| | - Anastasiya N Nezdyur
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ, 08028, USA
| | - Matthew Krevetski
- Department of Biological Sciences, Rowan University, Glassboro, NJ, 08028, USA
| | - Leonid Anikin
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA.,Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA
| | - Vincent J Manna
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA.,Graduate School of Biomedical Sciences, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA
| | - Natalie Minkovsky
- Department of Biological Sciences, Rowan University, Glassboro, NJ, 08028, USA
| | - Dimitri G Pestov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ, 08084, USA.
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231
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Affiliation(s)
- Roberto Valli
- Medical Genetic Unit, Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Annalisa Frattini
- UOS Milano, Institute of Genetics and Biomedical Research, National Research Council, Milano, Italy
- Department of Medicine and Surgery, University of Insubria, Milano, Italy
| | - Antonella Minelli
- Medical Genetic Unit, Department of Molecular Medicine, University of Pavia, Pavia, Italy
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232
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Kulkarni S, Dolezal JM, Wang H, Jackson L, Lu J, Frodey BP, Dosunmu-Ogunbi A, Li Y, Fromherz M, Kang A, Santana-Santos L, Benos PV, Prochownik EV. Ribosomopathy-like properties of murine and human cancers. PLoS One 2017; 12:e0182705. [PMID: 28820908 PMCID: PMC5562309 DOI: 10.1371/journal.pone.0182705] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/24/2017] [Indexed: 12/19/2022] Open
Abstract
Ribosomopathies comprise a heterogeneous group of hematologic and developmental disorders, often characterized by bone marrow failure, skeletal and other developmental abnormalities and cancer predisposition. They are associated with mutations and/or haplo-insufficiencies of ribosomal proteins (RPs) and inefficient ribosomal RNA (rRNA) processing. The resulting ribosomal stress induces the canonical p19ARF/Mdm2/p53 tumor suppressor pathway leading to proliferative arrest and/or apoptosis. It has been proposed that this pathway is then inactivated during subsequent neoplastic evolution. We show here that two murine models of hepatoblastoma (HB) and hepatocellular carcinoma (HCC) unexpectedly possess features that mimic the ribosomopathies. These include loss of the normal stoichiometry of RP transcripts and proteins and the accumulation of unprocessed rRNA precursors. Silencing of p19ARF, cytoplasmic sequestration of p53, binding to and inactivation of Mdm2 by free RPs, and up-regulation of the pro-survival protein Bcl-2 may further cooperate to drive tumor growth and survival. Consistent with this notion, re-instatement of constitutive p19ARF expression in the HB model completely suppressed tumorigenesis. In >2000 cases of human HCC, colorectal, breast, and prostate cancer, RP transcript deregulation was a frequent finding. In HCC and breast cancer, the severity of this dysregulation was associated with inferior survival. In HCC, the presence of RP gene mutations, some of which were identical to those previously reported in ribosomopathies, were similarly negatively correlated with long-term survival. Taken together, our results indicate that many if not all cancers possess ribosomopathy-like features that may affect their biological behaviors.
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Affiliation(s)
- Sucheta Kulkarni
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - James M. Dolezal
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Huabo Wang
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Laura Jackson
- Division of Newborn Medicine, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Jie Lu
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Brian P. Frodey
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Atinuke Dosunmu-Ogunbi
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Youjun Li
- College of Life Sciences and The State Key Laboratory of Virology, Wuhan University, Wuhan, Hubei Province, People’s Republic of China
| | - Marc Fromherz
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Audry Kang
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
| | - Lucas Santana-Santos
- Department of Computational and Systems Biology, The University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Panayiotis V. Benos
- Department of Computational and Systems Biology, The University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Biomedical Informatics, The University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Edward V. Prochownik
- Division of Hematology/Oncology, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, United States of America
- The Department of Microbiology and Molecular Genetics, The University of Pittsburgh School of Medicine, Pittsburgh, PA, United States of America
- The University of Pittsburgh Cancer Institute, Pittsburgh PA, United States of America
- * E-mail:
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233
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The roles of RRP15 in nucleolar formation, ribosome biogenesis and checkpoint control in human cells. Oncotarget 2017; 8:13240-13252. [PMID: 28099941 PMCID: PMC5355092 DOI: 10.18632/oncotarget.14658] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 12/27/2016] [Indexed: 01/05/2023] Open
Abstract
The nucleolus controls ribosome biogenesis and its perturbation induces nucleolar stress that inhibits cell cycle progression and activates checkpoint responses. Here, we investigate the roles of ribosomal RNA processing protein, RRP15, in nucleolar formation, ribosome biogenesis, cell cycle progression and checkpoint control in human cells. RRP15 is localized in the nucleolus and required for nucleolar formation. In contrast to the budding yeast Rrp15p that was reported as a component of pre-60S subunits, RRP15 is found in both pre-40S and pre-60S subunits and involved in regulating rRNA transcription and ribosome biogenesis. Perturbation of RRP15 induces nucleolar stress that activates RPL5/RPL11/5S rRNA (RP)-Mdm2-p53 axis checkpoint response and arrests cells at G1-G1/S in p53-proficient non-transformed RPE1 cells but not in p53-deficient HeLa and MCF7 tumor cells. Instead, p53-deficient HeLa and MCF7 cells with RRP15-dependent nucleolar stress enter S-phase with S-phase perturbation that activates ATR-Chk1- γH2AX axis DNA replication/damage checkpoint response, delaying S-G2/M progression and, ultimately, causing cell death. The selective checkpoint response, cell cycle inhibition and/or cytotoxicity induced by RRP15-dependent nucleolar stress in p53-proficient non-transformed cells and p53-deficient tumor cells suggest that RRP15 might be a potential target for cancer therapy.
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234
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Ishikawa H, Yoshikawa H, Izumikawa K, Miura Y, Taoka M, Nobe Y, Yamauchi Y, Nakayama H, Simpson RJ, Isobe T, Takahashi N. Poly(A)-specific ribonuclease regulates the processing of small-subunit rRNAs in human cells. Nucleic Acids Res 2017; 45:3437-3447. [PMID: 27899605 PMCID: PMC5389690 DOI: 10.1093/nar/gkw1047] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 10/24/2016] [Indexed: 11/14/2022] Open
Abstract
Ribosome biogenesis occurs successively in the nucleolus, nucleoplasm, and cytoplasm. Maturation of the ribosomal small subunit is completed in the cytoplasm by incorporation of a particular class of ribosomal proteins and final cleavage of 18S-E pre-rRNA (18S-E). Here, we show that poly(A)-specific ribonuclease (PARN) participates in steps leading to 18S-E maturation in human cells. We found PARN as a novel component of the pre-40S particle pulled down with the pre-ribosome factor LTV1 or Bystin. Reverse pull-down analysis revealed that PARN is a constitutive component of the Bystin-associated pre-40S particle. Knockdown of PARN or exogenous expression of an enzyme-dead PARN mutant (D28A) accumulated 18S-E in both the cytoplasm and nucleus. Moreover, expression of D28A accumulated 18S-E in Bystin-associated pre-40S particles, suggesting that the enzymatic activity of PARN is necessary for the release of 18S-E from Bystin-associated pre-40S particles. Finally, RNase H-based fragmentation analysis and 3΄-sequence analysis of 18S-E species present in cells expressing wild-type PARN or D28A suggested that PARN degrades the extended regions encompassing nucleotides 5-44 at the 3΄ end of mature 18S rRNA. Our results reveal a novel role for PARN in ribosome biogenesis in human cells.
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Affiliation(s)
- Hideaki Ishikawa
- Graduate School of Agriculture, 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
| | - Harunori Yoshikawa
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Keiichi Izumikawa
- Graduate School of Agriculture, 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
| | - Yutaka Miura
- Graduate School of Agriculture, 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
| | - Masato Taoka
- Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Yuko Nobe
- Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Yoshio Yamauchi
- Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Hiroshi Nakayama
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1, Hirosawa, Wako, Saitama 351-0198, 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
| | - Toshiaki Isobe
- Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Nobuhiro Takahashi
- Graduate School of Agriculture, 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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235
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Rogell B, Fischer B, Rettel M, Krijgsveld J, Castello A, Hentze MW. Specific RNP capture with antisense LNA/DNA mixmers. RNA (NEW YORK, N.Y.) 2017; 23:1290-1302. [PMID: 28476952 PMCID: PMC5513073 DOI: 10.1261/rna.060798.117] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/25/2017] [Indexed: 05/07/2023]
Abstract
RNA-binding proteins (RBPs) play essential roles in RNA biology, responding to cellular and environmental stimuli to regulate gene expression. Important advances have helped to determine the (near) complete repertoires of cellular RBPs. However, identification of RBPs associated with specific transcripts remains a challenge. Here, we describe "specific ribonucleoprotein (RNP) capture," a versatile method for the determination of the proteins bound to specific transcripts in vitro and in cellular systems. Specific RNP capture uses UV irradiation to covalently stabilize protein-RNA interactions taking place at "zero distance." Proteins bound to the target RNA are captured by hybridization with antisense locked nucleic acid (LNA)/DNA oligonucleotides covalently coupled to a magnetic resin. After stringent washing, interacting proteins are identified by quantitative mass spectrometry. Applied to in vitro extracts, specific RNP capture identifies the RBPs bound to a reporter mRNA containing the Sex-lethal (Sxl) binding motifs, revealing that the Sxl homolog sister of Sex lethal (Ssx) displays similar binding preferences. This method also revealed the repertoire of RBPs binding to 18S or 28S rRNAs in HeLa cells, including previously unknown rRNA-binding proteins.
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Affiliation(s)
- Birgit Rogell
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Bernd Fischer
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
- German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Mandy Rettel
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Jeroen Krijgsveld
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
- German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Alfredo Castello
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Matthias W Hentze
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
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236
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Milek M, Imami K, Mukherjee N, Bortoli FD, Zinnall U, Hazapis O, Trahan C, Oeffinger M, Heyd F, Ohler U, Selbach M, Landthaler M. DDX54 regulates transcriptome dynamics during DNA damage response. Genome Res 2017; 27:1344-1359. [PMID: 28596291 PMCID: PMC5538551 DOI: 10.1101/gr.218438.116] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/05/2017] [Indexed: 12/12/2022]
Abstract
The cellular response to genotoxic stress is mediated by a well-characterized network of DNA surveillance pathways. The contribution of post-transcriptional gene regulatory networks to the DNA damage response (DDR) has not been extensively studied. Here, we systematically identified RNA-binding proteins differentially interacting with polyadenylated transcripts upon exposure of human breast carcinoma cells to ionizing radiation (IR). Interestingly, more than 260 proteins, including many nucleolar proteins, showed increased binding to poly(A)+ RNA in IR-exposed cells. The functional analysis of DDX54, a candidate genotoxic stress responsive RNA helicase, revealed that this protein is an immediate-to-early DDR regulator required for the splicing efficacy of its target IR-induced pre-mRNAs. Upon IR exposure, DDX54 acts by increased interaction with a well-defined class of pre-mRNAs that harbor introns with weak acceptor splice sites, as well as by protein-protein contacts within components of U2 snRNP and spliceosomal B complex, resulting in lower intron retention and higher processing rates of its target transcripts. Because DDX54 promotes survival after exposure to IR, its expression and/or mutation rate may impact DDR-related pathologies. Our work indicates the relevance of many uncharacterized RBPs potentially involved in the DDR.
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Affiliation(s)
- Miha Milek
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Koshi Imami
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Neelanjan Mukherjee
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Francesca De Bortoli
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Ulrike Zinnall
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Orsalia Hazapis
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
| | - Christian Trahan
- Institut de Recherches Cliniques de Montréal, H2W 1R7 Montréal, Quebec, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, H3A 1A3 Montréal, Quebec, Canada
| | - Marlene Oeffinger
- Institut de Recherches Cliniques de Montréal, H2W 1R7 Montréal, Quebec, Canada
- Département de Biochimie, Faculté de Médecine, Université de Montréal, H3A 1A3 Montréal, Quebec, Canada
- Faculty of Medicine, Division of Experimental Medicine, McGill University, H3T 1J4 Montréal, Quebec, Canada
| | - Florian Heyd
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, 14195 Berlin, Germany
| | - Uwe Ohler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
- Department of Computer Science, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Matthias Selbach
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- Charite-Universitätsmedizin Berlin, 10115 Berlin, Germany
| | - Markus Landthaler
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin Institute for Medical Systems Biology, 13125 Berlin, Germany
- IRI Life Sciences, Institute of Biology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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237
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An Mtr4/ZFC3H1 complex facilitates turnover of unstable nuclear RNAs to prevent their cytoplasmic transport and global translational repression. Genes Dev 2017; 31:1257-1271. [PMID: 28733371 PMCID: PMC5558927 DOI: 10.1101/gad.302604.117] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 06/22/2017] [Indexed: 12/12/2022]
Abstract
Ogami et al. highlight a critical role for Mtr4/ZFC3H1 in nuclear surveillance of naturally unstable lncRNAs to prevent their accumulation, transport to the cytoplasm, and resultant disruption of protein synthesis. Many long noncoding RNAs (lncRNAs) are unstable and rapidly degraded in the nucleus by the nuclear exosome. An exosome adaptor complex called NEXT (nuclear exosome targeting) functions to facilitate turnover of some of these lncRNAs. Here we show that knockdown of one NEXT subunit, Mtr4, but neither of the other two subunits, resulted in accumulation of two types of lncRNAs: prematurely terminated RNAs (ptRNAs) and upstream antisense RNAs (uaRNAs). This suggested a NEXT-independent Mtr4 function, and, consistent with this, we isolated a distinct complex containing Mtr4 and the zinc finger protein ZFC3H1. Strikingly, knockdown of either protein not only increased pt/uaRNA levels but also led to their accumulation in the cytoplasm. Furthermore, all pt/uaRNAs examined associated with active ribosomes, but, paradoxically, this correlated with a global reduction in heavy polysomes and overall repression of translation. Our findings highlight a critical role for Mtr4/ZFC3H1 in nuclear surveillance of naturally unstable lncRNAs to prevent their accumulation, transport to the cytoplasm, and resultant disruption of protein synthesis.
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238
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Probing the mechanisms underlying human diseases in making ribosomes. Biochem Soc Trans 2017; 44:1035-44. [PMID: 27528749 DOI: 10.1042/bst20160064] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Indexed: 12/26/2022]
Abstract
Ribosomes are essential, highly complex machines responsible for protein synthesis in all growing cells. Because of their importance, the process of building these machines is intricately regulated. Although the proteins involved in regulating ribosome biogenesis are just beginning to be understood, especially in human cells, the consequences for dysregulating this process have been even less studied. Such interruptions in ribosome synthesis result in a collection of human disorders known as ribosomopathies. Ribosomopathies, which occur due to mutations in proteins involved in the global process of ribosome biogenesis, result in tissue-specific defects. The questions posed by this dichotomy and the steps taken to address these questions are therefore the focus of this review: How can tissue-specific disorders result from alterations in global processes? Could ribosome specialization account for this difference?
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239
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Justilien V, Lewis KC, Murray NR, Fields AP. Oncogenic Ect2 signaling regulates rRNA synthesis in NSCLC. Small GTPases 2017; 10:388-394. [PMID: 28657426 DOI: 10.1080/21541248.2017.1335274] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
The Rho GTPase family members Rac1, Cdc42 and RhoA play key contributory roles in the transformed phenotype of human cancers. Epithelial Cell Transforming Sequence 2 (Ect2), a guanine nucleotide exchange factor (GEF) for these Rho GTPases, has also been implicated in a variety of human cancers. We have shown that Ect2 is frequently overexpressed in both major forms of non-small cell lung cancer (NSCLC), lung adenocarcinoma (LADC) and lung squamous cell carcinoma (LSCC), which together make up approximately 70% of all lung cancer diagnoses. Furthermore, we have found that Ect2 is required for multiple aspects of the transformed phenotype of NSCLC cells including transformed growth and invasion in vitro and tumorigenesis in vivo. More recently, we showed that a major mechanism by which Ect2 drives KRAS-mediated LADC transformation is by regulating rRNA (rRNA) synthesis. However, it remains unclear whether Ect2 plays a similar role in ribosome biogenesis in LSCC. Here we demonstrate that Ect2 expression correlates positively with expression of ribosome biogenesis genes and with pre-ribosomal 45S RNA abundance in primary LSCC tumors. Furthermore, we demonstrate that Ect2 functionally regulates rRNA synthesis in LSCC cells. Based on these data, we propose that inhibition of Ect2-mediated nucleolar signaling holds promise as a potential therapeutic strategy for improved treatment of both LADC and LSCC.
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Affiliation(s)
- Verline Justilien
- a Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center , Jacksonville , FL , USA
| | - Kayla C Lewis
- a Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center , Jacksonville , FL , USA
| | - Nicole R Murray
- a Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center , Jacksonville , FL , USA
| | - Alan P Fields
- a Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center , Jacksonville , FL , USA
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240
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Burke JM, Kincaid RP, Nottingham RM, Lambowitz AM, Sullivan CS. DUSP11 activity on triphosphorylated transcripts promotes Argonaute association with noncanonical viral microRNAs and regulates steady-state levels of cellular noncoding RNAs. Genes Dev 2017; 30:2076-2092. [PMID: 27798849 PMCID: PMC5066614 DOI: 10.1101/gad.282616.116] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/02/2016] [Indexed: 12/22/2022]
Abstract
Here, Burke et al. delineate a new pathway for mammalian small RNAs to enter the RNAi gene silencing machinery. They show that DUSP11 directly dephosphorylates viral triphosphate ncRNA transcripts and that this is required for efficient silencing by RISC, suggesting that mammalian viral pathogens can use DUSP11 to generate atypical microRNAs. RNA silencing is a conserved eukaryotic gene expression regulatory mechanism mediated by small RNAs. In Caenorhabditis elegans, the accumulation of a distinct class of siRNAs synthesized by an RNA-dependent RNA polymerase (RdRP) requires the PIR-1 phosphatase. However, the function of PIR-1 in RNAi has remained unclear. Since mammals lack an analogous siRNA biogenesis pathway, an RNA silencing role for the mammalian PIR-1 homolog (dual specificity phosphatase 11 [DUSP11]) was unexpected. Here, we show that the RNA triphosphatase activity of DUSP11 promotes the RNA silencing activity of viral microRNAs (miRNAs) derived from RNA polymerase III (RNAP III) transcribed precursors. Our results demonstrate that DUSP11 converts the 5′ triphosphate of miRNA precursors to a 5′ monophosphate, promoting loading of derivative 5p miRNAs into Argonaute proteins via a Dicer-coupled 5′ monophosphate-dependent strand selection mechanism. This mechanistic insight supports a likely shared function for PIR-1 in C. elegans. Furthermore, we show that DUSP11 modulates the 5′ end phosphate group and/or steady-state level of several host RNAP III transcripts, including vault RNAs and Alu transcripts. This study shows that steady-state levels of select noncoding RNAs are regulated by DUSP11 and defines a previously unknown portal for small RNA-mediated silencing in mammals, revealing that DUSP11-dependent RNA silencing activities are shared among diverse metazoans.
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Affiliation(s)
- James M Burke
- Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Department of Molecular Biosciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,John Ring LaMontagne Center for Infectious Disease, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Rodney P Kincaid
- Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Department of Molecular Biosciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,John Ring LaMontagne Center for Infectious Disease, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Ryan M Nottingham
- Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Department of Molecular Biosciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Department of Molecular Biosciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Christopher S Sullivan
- Institute for Cellular and Molecular Biology, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Department of Molecular Biosciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.,John Ring LaMontagne Center for Infectious Disease, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA
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241
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Warda AS, Freytag B, Haag S, Sloan KE, Görlich D, Bohnsack MT. Effects of the Bowen-Conradi syndrome mutation in EMG1 on its nuclear import, stability and nucleolar recruitment. Hum Mol Genet 2017; 25:5353-5364. [PMID: 27798105 PMCID: PMC5418833 DOI: 10.1093/hmg/ddw351] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 10/11/2016] [Indexed: 12/14/2022] Open
Abstract
Bowen-Conradi syndrome (BCS) is a severe genetic disorder that is characterised by various developmental abnormalities, bone marrow failure and early infant death. This disease is caused by a single mutation leading to the aspartate 86 to glycine (D86G) exchange in the essential nucleolar RNA methyltransferase EMG1. EMG1 is required for the synthesis of the small ribosomal subunit and is involved in modification of the 18S ribosomal RNA. Here, we identify the pre-ribosomal factors NOP14, NOC4L and UTP14A as members of a nucleolar subcomplex that contains EMG1 and is required for its recruitment to nucleoli. The BCS mutation in EMG1 leads to reduced nucleolar localisation, accumulation of EMG1D86G in nuclear foci and its proteasome-dependent degradation. We further show that EMG1 can be imported into the nucleus by the importins (Imp) Impα/β or Impβ/7. Interestingly, in addition to its role in nuclear import, binding of the Impβ/7 heterodimer can prevent unspecific aggregation of both EMG1 and EMG1D86G on RNAs in vitro, indicating that the importins act as chaperones by binding to basic regions of the RNA methyltransferase. Our findings further indicate that in BCS, nuclear disassembly of the import complex and release of EMG1D86G lead to its nuclear aggregation and degradation, resulting in the reduced nucleolar recruitment of the RNA methyltransferase and defects in the biogenesis of the small ribosomal subunit.
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Affiliation(s)
- Ahmed S Warda
- Institute for Molecular Biology, Georg-August University, Göttingen, Germany
| | - Bernard Freytag
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sara Haag
- Institute for Molecular Biology, Georg-August University, Göttingen, Germany
| | - Katherine E Sloan
- Institute for Molecular Biology, Georg-August University, Göttingen, Germany
| | - Dirk Görlich
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Markus T Bohnsack
- Institute for Molecular Biology, Georg-August University, Göttingen, Germany.,Göttingen Center for Molecular Biosciences, Georg-August-University, Göttingen, Germany
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242
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Tomecki R, Sikorski PJ, Zakrzewska-Placzek M. Comparison of preribosomal RNA processing pathways in yeast, plant and human cells - focus on coordinated action of endo- and exoribonucleases. FEBS Lett 2017; 591:1801-1850. [PMID: 28524231 DOI: 10.1002/1873-3468.12682] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 12/17/2022]
Abstract
Proper regulation of ribosome biosynthesis is mandatory for cellular adaptation, growth and proliferation. Ribosome biogenesis is the most energetically demanding cellular process, which requires tight control. Abnormalities in ribosome production have severe consequences, including developmental defects in plants and genetic diseases (ribosomopathies) in humans. One of the processes occurring during eukaryotic ribosome biogenesis is processing of the ribosomal RNA precursor molecule (pre-rRNA), synthesized by RNA polymerase I, into mature rRNAs. It must not only be accurate but must also be precisely coordinated with other phenomena leading to the synthesis of functional ribosomes: RNA modification, RNA folding, assembly with ribosomal proteins and nucleocytoplasmic RNP export. A multitude of ribosome biogenesis factors ensure that these events take place in a correct temporal order. Among them are endo- and exoribonucleases involved in pre-rRNA processing. Here, we thoroughly present a wide spectrum of ribonucleases participating in rRNA maturation, focusing on their biochemical properties, regulatory mechanisms and substrate specificity. We also discuss cooperation between various ribonucleolytic activities in particular stages of pre-rRNA processing, delineating major similarities and differences between three representative groups of eukaryotes: yeast, plants and humans.
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Affiliation(s)
- Rafal Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Poland
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243
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Myeloid neoplasms with germline DDX41 mutation. Int J Hematol 2017; 106:163-174. [DOI: 10.1007/s12185-017-2260-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 12/19/2022]
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244
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Espinar-Marchena FJ, Babiano R, Cruz J. Placeholder factors in ribosome biogenesis: please, pave my way. MICROBIAL CELL 2017; 4:144-168. [PMID: 28685141 PMCID: PMC5425277 DOI: 10.15698/mic2017.05.572] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The synthesis of cytoplasmic eukaryotic ribosomes is an extraordinarily energy-demanding cellular activity that occurs progressively from the nucleolus to the cytoplasm. In the nucleolus, precursor rRNAs associate with a myriad of trans-acting factors and some ribosomal proteins to form pre-ribosomal particles. These factors include snoRNPs, nucleases, ATPases, GTPases, RNA helicases, and a vast list of proteins with no predicted enzymatic activity. Their coordinate activity orchestrates in a spatiotemporal manner the modification and processing of precursor rRNAs, the rearrangement reactions required for the formation of productive RNA folding intermediates, the ordered assembly of the ribosomal proteins, and the export of pre-ribosomal particles to the cytoplasm; thus, providing speed, directionality and accuracy to the overall process of formation of translation-competent ribosomes. Here, we review a particular class of trans-acting factors known as "placeholders". Placeholder factors temporarily bind selected ribosomal sites until these have achieved a structural context that is appropriate for exchanging the placeholder with another site-specific binding factor. By this strategy, placeholders sterically prevent premature recruitment of subsequently binding factors, premature formation of structures, avoid possible folding traps, and act as molecular clocks that supervise the correct progression of pre-ribosomal particles into functional ribosomal subunits. We summarize the current understanding of those factors that delay the assembly of distinct ribosomal proteins or subsequently bind key sites in pre-ribosomal particles. We also discuss recurrent examples of RNA-protein and protein-protein mimicry between rRNAs and/or factors, which have clear functional implications for the ribosome biogenesis pathway.
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Affiliation(s)
- Francisco J Espinar-Marchena
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain
| | - Reyes Babiano
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain.,Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain
| | - Jesús Cruz
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, and Departamento de Genética, Universidad de Sevilla, E-41013, Seville, Spain
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245
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Simsek D, Barna M. An emerging role for the ribosome as a nexus for post-translational modifications. Curr Opin Cell Biol 2017; 45:92-101. [PMID: 28445788 DOI: 10.1016/j.ceb.2017.02.010] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 02/25/2017] [Indexed: 01/01/2023]
Abstract
The ribosome is one of life's most ancient molecular machines that has historically been viewed as a backstage participant in gene regulation, translating the genetic code across all kingdoms of life in a rote-like fashion. However, recent studies suggest that intrinsic components of the ribosome can be regulated and diversified as a means to intricately control the expression of the cellular proteome. In this review, we discuss advances in the characterization of ribosome post-translational modifications (PTMs) from past to present. We specifically focus on emerging examples of ribosome phosphorylation and ubiquitylation, which are beginning to showcase that PTMs of the ribosome are versatile, may have functional consequences for translational control, and are intimately linked to human disease. We further highlight the key questions that remain to be addressed to gain a more complete picture of the array of ribosome PTMs and the upstream enzymes that control them, which may endow ribosomes with greater regulatory potential in gene regulation and control of cellular homeostasis.
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Affiliation(s)
- Deniz Simsek
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Maria Barna
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
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246
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Burke JM, Sullivan CS. DUSP11 - An RNA phosphatase that regulates host and viral non-coding RNAs in mammalian cells. RNA Biol 2017; 14:1457-1465. [PMID: 28296624 PMCID: PMC5785229 DOI: 10.1080/15476286.2017.1306169] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dual-specificity phosphatase 11 (DUSP11) is a conserved protein tyrosine phosphatase (PTP) in metazoans. The cellular substrates and physiologic activities of DUSP11 remain largely unknown. In nematodes, DUSP11 is required for normal development and RNA interference against endogenous RNAs (endo-RNAi) via molecular mechanisms that are not well understood. However, mammals lack analogous endo-RNAi pathways and consequently, a role for DUSP11 in mammalian RNA silencing was unanticipated. Recent work from our laboratory demonstrated that DUSP11 activity alters the silencing potential of noncanonical viral miRNAs in mammalian cells. Our studies further uncovered direct cellular substrates of DUSP11 and suggest that DUSP11 is part of regulatory pathway that controls the abundance of select triphosphorylated noncoding RNAs. Here, we highlight recent findings and present new data that advance understanding of mammalian DUSP11 during gene silencing and discuss the emerging biological activities of DUSP11 in mammalian cells.
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Affiliation(s)
- James M Burke
- a The University of Texas at Austin , Center for Systems and Synthetic Biology, Center for Infectious Disease and Department of Molecular Biosciences , Austin , TX , USA
| | - Christopher S Sullivan
- a The University of Texas at Austin , Center for Systems and Synthetic Biology, Center for Infectious Disease and Department of Molecular Biosciences , Austin , TX , USA
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Shen W, Liang XH, Sun H, De Hoyos CL, Crooke ST. Depletion of NEAT1 lncRNA attenuates nucleolar stress by releasing sequestered P54nrb and PSF to facilitate c-Myc translation. PLoS One 2017; 12:e0173494. [PMID: 28288210 PMCID: PMC5348036 DOI: 10.1371/journal.pone.0173494] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 02/21/2017] [Indexed: 12/03/2022] Open
Abstract
Altered expression of NEAT1, the architectural long non-coding RNA (lncRNA) of nuclear paraspeckles, has been reported during tumorigenesis, as well as under various cellular stress conditions. Here we report that the depletion of NEAT1 lncRNA alleviates nucleolar stress during RNAP I inhibition through releasing sequestered P54nrb and PSF to facilitate the IRES-dependent translation of c-Myc. RNAP I inhibitor CX5461 disrupts the SL1-rDNA interaction and induces nucleolar disruption, demonstrated by the accumulation of fibrillarin-containing nucleoplasmic foci and nucleolar clearance of ribosomal proteins in HeLa cells. Antisense oligonucleotide-mediated depletion of NEAT1 lncRNA significantly attenuated the RNAP I inhibition and its related nucleolar disruption. Interestingly, induction in the levels of c-Myc protein was observed in NEAT1-depeleted cells under RNAP I inhibition. NEAT1-associated paraspeckle proteins P54nrb and PSF have been reported as positive regulators of c-Myc translation through interaction with c-Myc IRES. Indeed, an increased association of P54nrb and PSF with c-Myc mRNA was observed in NEAT1-depleted cells. Moreover, apoptosis was observed in HeLa cells depleted of P54nrb and PSF, further confirming the positive involvement of P54nrb and PSF in cell proliferation. Together, our results suggest that NEAT1 depletion rescues CX5461-induced nucleolar stress through facilitating c-Myc translation by relocating P54nrb/PSF from nuclear paraspeckles to c-Myc mRNAs.
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Affiliation(s)
- Wen Shen
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA, United States of America
| | - Xue-hai Liang
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA, United States of America
| | - Hong Sun
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA, United States of America
| | - Cheryl L. De Hoyos
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA, United States of America
| | - Stanley T. Crooke
- Department of Core Antisense Research, IONIS Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA, United States of America
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248
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Tao T, Sondalle SB, Shi H, Zhu S, Perez-Atayde AR, Peng J, Baserga SJ, Look AT. The pre-rRNA processing factor DEF is rate limiting for the pathogenesis of MYCN-driven neuroblastoma. Oncogene 2017; 36:3852-3867. [PMID: 28263972 PMCID: PMC5501763 DOI: 10.1038/onc.2016.527] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/08/2016] [Accepted: 12/22/2016] [Indexed: 02/07/2023]
Abstract
The nucleolar factor, digestive organ expansion factor (DEF), has a key role in ribosome biogenesis, functioning in pre-ribosomal RNA (pre-rRNA) processing as a component of the small ribosomal subunit (SSU) processome. Here we show that the peripheral sympathetic nervous system (PSNS) is very underdeveloped in def-deficient zebrafish, and that def haploinsufficiency significantly decreases disease penetrance and tumor growth rate in a MYCN-driven transgenic zebrafish model of neuroblastoma that arises in the PSNS. Consistent with these findings, DEF is highly expressed in human neuroblastoma, and its depletion in human neuroblastoma cell lines induces apoptosis. Interestingly, overexpression of MYCN in zebrafish and in human neuroblastoma cells results in the appearance of intermediate pre-rRNAs species that reflect the processing of pre-rRNAs through Pathway 2, a pathway that processes pre-rRNAs in a different temporal order than the more often used Pathway 1. Our results indicate that DEF and possibly other components of the SSU processome provide a novel site of vulnerability in neuroblastoma cells that could be exploited for targeted therapy.
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Affiliation(s)
- T Tao
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - S B Sondalle
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - H Shi
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.,College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - S Zhu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Cancer Center and Mayo Clinic Center for Individualized Medicine, Rochester, MN, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Mayo Clinic Cancer Center and Mayo Clinic Center for Individualized Medicine, Rochester, MN, USA
| | - A R Perez-Atayde
- Department of Pathology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA
| | - J Peng
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - S J Baserga
- Departments of Molecular Biophysics &Biochemistry, Genetics and Therapeutic Radiology, Yale University and Yale University School of Medicine, New Haven, CT, USA
| | - A T Look
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
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Ogawa LM, Baserga SJ. Crosstalk between the nucleolus and the DNA damage response. MOLECULAR BIOSYSTEMS 2017; 13:443-455. [PMID: 28112326 PMCID: PMC5340083 DOI: 10.1039/c6mb00740f] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nucleolar function and the cellular response to DNA damage have long been studied as distinct disciplines. New research and a new appreciation for proteins holding multiple functional roles, however, is beginning to change the way we think about the crosstalk among distinct cellular processes. Here, we focus on the crosstalk between the DNA damage response and the nucleolus, including a comprehensive review of the literature that reveals a role for conventional DNA repair proteins in ribosome biogenesis, and conversely, ribosome biogenesis proteins in DNA repair. Furthermore, with recent advances in nucleolar proteomics and a growing list of proteins that localize to the nucleolus, it is likely that we will continue to identify new DNA repair proteins with a nucleolar-specific role. Given the importance of ribosome biogenesis and DNA repair in essential cellular processes and the role that they play in diverse pathologies, continued elucidation of the overlap between these two disciplines will be essential to the advancement of both fields and to the development of novel therapeutics.
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Affiliation(s)
- L M Ogawa
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - S J Baserga
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA. and Department of Genetics, Yale University School of Medicine, New Haven, CT 06520, USA and Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520, USA
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250
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Identification of novel cancer therapeutic targets using a designed and pooled shRNA library screen. Sci Rep 2017; 7:43023. [PMID: 28223711 PMCID: PMC5320502 DOI: 10.1038/srep43023] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 01/17/2017] [Indexed: 01/08/2023] Open
Abstract
Targeted cancer therapeutics aim to exploit tumor-specific, genetic vulnerabilities specifically affecting neoplastic cells without similarly affecting normal cells. Here we performed sequencing-based screening of an shRNA library on a panel of cancer cells of different origins as well as normal cells. The shRNA library was designed to target a subset of genes previously identified using a whole genome screening approach. This focused shRNA library was infected into cells followed by analysis of enrichment and depletion of the shRNAs over the course of cell proliferation. We developed a bootstrap likelihood ratio test for the interpretation of the effects of multiple shRNAs over multiple cell line passages. Our analysis identified 44 genes whose depletion preferentially inhibited the growth of cancer cells. Among these genes ribosomal protein RPL35A, putative RNA helicase DDX24, and coatomer complex I (COPI) subunit ARCN1 most significantly inhibited growth of multiple cancer cell lines without affecting normal cell growth and survival. Further investigation revealed that the growth inhibition caused by DDX24 depletion is independent of p53 status underlining its value as a drug target. Overall, our study establishes a new approach for the analysis of proliferation-based shRNA selection strategies and identifies new targets for the development of cancer therapeutics.
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