51
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Yatsuka H, Hada K, Shiraishi H, Umeda R, Morisaki I, Urushibata H, Shimizu N, Sebastian WA, Hikida T, Ishitani T, Hanada R, Shimada T, Kimoto K, Kubota T, Hanada T. Exosc2 deficiency leads to developmental disorders by causing a nucleotide pool imbalance in zebrafish. Biochem Biophys Res Commun 2020; 533:1470-1476. [PMID: 33333712 DOI: 10.1016/j.bbrc.2020.10.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 10/17/2020] [Indexed: 02/07/2023]
Abstract
Exosc2 is one of the components of the exosome complex involved in RNA 3' end processing and degradation of various RNAs. Recently, EXOSC2 mutation has been reported in German families presenting short stature, hearing loss, retinitis pigmentosa, and premature aging. However, the in vivo function of EXOSC2 has been elusive. Herein, we generated Exosc2 knockout (exosc2-/-) zebrafish that showed larval lethality 13 days post fertilization, with microcephaly, loss of spinal motor neurons, myelin deficiency, and retinitis pigmentosa. Mechanistically, Exosc2 deficiency caused impaired mRNA turnover, resulting in a nucleotide pool imbalance. Rapamycin, which modulated mRNA turnover by inhibiting the mTOR pathway, improved nucleotide pool imbalance in exosc2-/- zebrafish, resulting in prolonged survival and partial rescue of neuronal defects. Taken together, our findings offer new insights into the disease pathogenesis caused by Exosc2 deficiency, and might help explain fundamental molecular mechanisms in neuronal diseases, such as Alzheimer's disease, amyotrophic lateral sclerosis, and spinal muscular atrophy.
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Affiliation(s)
- Hiroyuki Yatsuka
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan; Department of Ophthalmology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Kazumasa Hada
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Hiroshi Shiraishi
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Ryohei Umeda
- Department of Neurophysiology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Ikuko Morisaki
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Hirotaro Urushibata
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Nobuyuki Shimizu
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Wulan Apridita Sebastian
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan; Institute of Tropical Disease, Airlangga University, Surabaya, Indonesia
| | - Takatoshi Hikida
- Laboratory for Advanced Brain Functions, Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Tohru Ishitani
- Department of Homeostatic Regulation, Division of Cellular and Molecular Biology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Reiko Hanada
- Department of Neurophysiology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Tatsuo Shimada
- Oita Medical Technology School, Japan College of Judo-Therapy, Acupuncture & Moxibustion Therapy, Oita, Japan
| | - Kenichi Kimoto
- Department of Ophthalmology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Toshiaki Kubota
- Department of Ophthalmology, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Toshikatsu Hanada
- Department of Cell Biology, Oita University Faculty of Medicine, Yufu, Oita, Japan.
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52
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Cirak S, Daimagüler HS, Moawia A, Koy A, Yis U. On the differential diagnosis of neuropathy in neurogenetic disorders. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Neuropathy might be the presenting or accompanying sign in many neurogenetic and metabolic disorders apart from the classical-peripheral neuropathies or motor-neuron diseases. This causes a diagnostic challenge which is of particular relevance since a number of the underlying diseases could be treated. Thus, we attempt to give a clinical overview on the most common genetic diseases with clinically manifesting neuropathy.
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Affiliation(s)
- Sebahattin Cirak
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
| | - Hülya-Sevcan Daimagüler
- Division of Pediatrics Neurology, Department of Pediatrics, Faculty of Medicine , Dokuz Eylul University , Izmir , Turkey
| | - Abubakar Moawia
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
| | - Anne Koy
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
| | - Uluc Yis
- Division of Pediatrics Neurology, Department of Pediatrics, Faculty of Medicine , Dokuz Eylul University , Izmir , Turkey
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53
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Kawabe Y, Mori K, Yamashita T, Gotoh S, Ikeda M. The RNA exosome complex degrades expanded hexanucleotide repeat RNA in C9orf72 FTLD/ALS. EMBO J 2020; 39:e102700. [PMID: 32830871 PMCID: PMC7527818 DOI: 10.15252/embj.2019102700] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/19/2020] [Accepted: 07/23/2020] [Indexed: 12/14/2022] Open
Abstract
Nucleotide repeat expansions in the C9orf72 gene cause frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Transcribed repeat RNA accumulates within RNA foci and is also translated into toxic dipeptide repeat proteins (DPR). The mechanism of repeat RNA accumulation, however, remains unclear. The RNA exosome complex is a multimeric ribonuclease involved in degradation of defective RNA. Here, we uncover the RNA exosome as a major degradation complex for pathogenic C9orf72‐derived repeat RNA. Knockdown of EXOSC10, the catalytic subunit of the complex, enhanced repeat RNA and DPR protein expression levels. RNA degradation assays confirmed that EXOSC10 can degrade both sense and antisense repeats. Furthermore, EXOSC10 reduction increased RNA foci and repeat transcripts in patient‐derived cells. Cells expressing toxic poly‐GR or poly‐PR proteins accumulate a subset of small nucleolar RNA precursors, which are physiological substrates of EXOSC10, as well as excessive repeat RNA, indicating that arginine‐rich DPR proteins impair the intrinsic activity of EXOSC10. Collectively, arginine‐rich DPR‐mediated impairment of EXOSC10 and the RNA exosome complex compromises repeat RNA metabolism and may thus exacerbate C9orf72‐FTLD/ALS pathologies in a vicious cycle.
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Affiliation(s)
- Yuya Kawabe
- Psychiatry, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kohji Mori
- Psychiatry, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Tomoko Yamashita
- Psychiatry, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shiho Gotoh
- Psychiatry, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Manabu Ikeda
- Psychiatry, Graduate School of Medicine, Osaka University, Osaka, Japan
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54
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de Abreu MS, Genario R, Giacomini AC, Demin KA, Lakstygal AM, Amstislavskaya TG, Fontana BD, Parker MO, Kalueff AV. Zebrafish as a Model of Neurodevelopmental Disorders. Neuroscience 2020; 445:3-11. [DOI: 10.1016/j.neuroscience.2019.08.034] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 07/21/2019] [Accepted: 08/20/2019] [Indexed: 12/14/2022]
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55
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Wermuth PJ, Jimenez SA. Molecular characteristics and functional differences of anti-PM/Scl autoantibodies and two other distinct and unique supramolecular structures known as "EXOSOMES". Autoimmun Rev 2020; 19:102644. [PMID: 32801042 DOI: 10.1016/j.autrev.2020.102644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 04/10/2020] [Indexed: 02/06/2023]
Abstract
The term "exosome" has been applied to three distinct supramolecular entities, namely the PM/Scl autoantibodies or "RNA exosomes", transforming DNA fragments termed "DNA exosomes", and small size extracellular vesicles knows as "exosomes". Some of the molecular components of the "PM/Scl exosome complex" or "RNA exosome" are recognized by specific autoantibodies present in the serum from some Systemic Sclerosis (SSc), polymyositis (PM) and polymyositis SSc (PM/Scl) overlap syndrome patients. On the other hand, one of the most active focuses of laboratory investigation in the last decade has been the biogenesis and role of extracellular vesicles known as "exosomes". The remarkable ability of these "exosome" vesicles to alter the cellular phenotype following fusion with target cells and the release of their macromolecular cargo has revealed a possible role in the pathogenesis of numerous diseases, including malignant, inflammatory, and autoimmune disorders and may allow them to serve as theranostic agents for personalized and precision medicine. The indiscriminate use of the term "exosome" to refer to these three distinct molecular entities has engendered great confusion in the scientific literature. Here, we review the molecular characteristics and functional differences between the three molecular structures identified as "exosomes". Given the rapidly growing scientific interest in extravesicular exosomes, unless a solution is found the confusion in the literature resulting from the use of the term "exosomes" will markedly increase.
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Affiliation(s)
- Peter J Wermuth
- Jefferson Institute of Molecular Medicine and Scleroderma Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - Sergio A Jimenez
- Jefferson Institute of Molecular Medicine and Scleroderma Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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56
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Jafari D, Malih S, Eini M, Jafari R, Gholipourmalekabadi M, Sadeghizadeh M, Samadikuchaksaraei A. Improvement, scaling-up, and downstream analysis of exosome production. Crit Rev Biotechnol 2020; 40:1098-1112. [PMID: 32772758 DOI: 10.1080/07388551.2020.1805406] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Exosomes are the most researched extracellular vesicles. In many biological, physiological, and pathological studies, they have been identified as suitable candidates for treatment and diagnosis of diseases by acting as the carriers of both drugs and genes. Considerable success has been achieved regarding the use of exosomes for tissue regeneration, cancer diagnosis, and targeted drug/gene delivery to specific tissues. While major progress has been made in exosome extraction and purification, extraction of large quantities of exosomes is still a major challenge. This issue limits the scope of both exosome-based research and therapeutic development. In this review, we have aimed to summarize experimental studies focused at increasing the number of exosomes. Biotechnological studies aimed at identifying the pathways of exosome biogenesis to manipulate some genes in order to increase the production of exosomes. Generally, two major strategies are employed to increase the production of exosomes. First, oogenesis pathways are genetically manipulated to overexpress activator genes of exosome biogenesis and downregulate the genes involved in exosome recycling pathways. Second, manipulation of the cell culture medium, treatment with specific drugs, and limiting certain conditions can force the cell to produce more exosomes. In this study, we have reviewed and categorized these strategies. It is hoped that the information presented in this review will provide a better understanding for expanding biotechnological approaches in exosome-based therapeutic development.
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Affiliation(s)
- Davod Jafari
- Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.,Student Research Committee, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Sara Malih
- Department of Medical Biotechnology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Maryam Eini
- Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Rasool Jafari
- Department of Medical Parasitology and Mycology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Mazaher Gholipourmalekabadi
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Tissue Engineering and Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Sadeghizadeh
- Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Ali Samadikuchaksaraei
- Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.,Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Tissue Engineering and Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
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57
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Morton DJ, Jalloh B, Kim L, Kremsky I, Nair RJ, Nguyen KB, Rounds JC, Sterrett MC, Brown B, Le T, Karkare MC, McGaughey KD, Sheng S, Leung SW, Fasken MB, Moberg KH, Corbett AH. A Drosophila model of Pontocerebellar Hypoplasia reveals a critical role for the RNA exosome in neurons. PLoS Genet 2020; 16:e1008901. [PMID: 32645003 PMCID: PMC7373318 DOI: 10.1371/journal.pgen.1008901] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 07/21/2020] [Accepted: 06/01/2020] [Indexed: 12/27/2022] Open
Abstract
The RNA exosome is an evolutionarily-conserved ribonuclease complex critically important for precise processing and/or complete degradation of a variety of cellular RNAs. The recent discovery that mutations in genes encoding structural RNA exosome subunits cause tissue-specific diseases makes defining the role of this complex within specific tissues critically important. Mutations in the RNA exosome component 3 (EXOSC3) gene cause Pontocerebellar Hypoplasia Type 1b (PCH1b), an autosomal recessive neurologic disorder. The majority of disease-linked mutations are missense mutations that alter evolutionarily-conserved regions of EXOSC3. The tissue-specific defects caused by these amino acid changes in EXOSC3 are challenging to understand based on current models of RNA exosome function with only limited analysis of the complex in any multicellular model in vivo. The goal of this study is to provide insight into how mutations in EXOSC3 impact the function of the RNA exosome. To assess the tissue-specific roles and requirements for the Drosophila ortholog of EXOSC3 termed Rrp40, we utilized tissue-specific RNAi drivers. Depletion of Rrp40 in different tissues reveals a general requirement for Rrp40 in the development of many tissues including the brain, but also highlight an age-dependent requirement for Rrp40 in neurons. To assess the functional consequences of the specific amino acid substitutions in EXOSC3 that cause PCH1b, we used CRISPR/Cas9 gene editing technology to generate flies that model this RNA exosome-linked disease. These flies show reduced viability; however, the surviving animals exhibit a spectrum of behavioral and morphological phenotypes. RNA-seq analysis of these Drosophila Rrp40 mutants reveals increases in the steady-state levels of specific mRNAs and ncRNAs, some of which are central to neuronal function. In particular, Arc1 mRNA, which encodes a key regulator of synaptic plasticity, is increased in the Drosophila Rrp40 mutants. Taken together, this study defines a requirement for the RNA exosome in specific tissues/cell types and provides insight into how defects in RNA exosome function caused by specific amino acid substitutions that occur in PCH1b can contribute to neuronal dysfunction.
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Affiliation(s)
- Derrick J. Morton
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Binta Jalloh
- Genetics and Molecular Biology Graduate Program, Emory University, NE, Atlanta, Georgia, United States of America
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Lily Kim
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Isaac Kremsky
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Rishi J. Nair
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Khuong B. Nguyen
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - J. Christopher Rounds
- Genetics and Molecular Biology Graduate Program, Emory University, NE, Atlanta, Georgia, United States of America
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Maria C. Sterrett
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
- Biochemistry, Cell and Developmental Biology Graduate Program, Emory University, NE, Atlanta, Georgia, United States of America
| | - Brianna Brown
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Thalia Le
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Maya C. Karkare
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Kathryn D. McGaughey
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Shaoyi Sheng
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Sara W. Leung
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Milo B. Fasken
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
| | - Kenneth H. Moberg
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Anita H. Corbett
- Department of Biology, RRC 1021, Emory University, NE, Atlanta, Georgia, United States of America
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58
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Otten ABC, Kamps R, Lindsey P, Gerards M, Pendeville-Samain H, Muller M, van Tienen FHJ, Smeets HJM. Tfam Knockdown Results in Reduction of mtDNA Copy Number, OXPHOS Deficiency and Abnormalities in Zebrafish Embryos. Front Cell Dev Biol 2020; 8:381. [PMID: 32596237 PMCID: PMC7303330 DOI: 10.3389/fcell.2020.00381] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/27/2020] [Indexed: 11/13/2022] Open
Abstract
High mitochondrial DNA (mtDNA) copy numbers are essential for oogenesis and embryogenesis and correlate with fertility of oocytes and viability of embryos. To understand the pathology and mechanisms associated with low mtDNA copy numbers, we knocked down mitochondrial transcription factor A (tfam), a regulator of mtDNA replication, during early zebrafish development. Reduction of tfam using a splice-modifying morpholino (MO) resulted in a 42 ± 17% decrease in mtDNA copy number in embryos at 4 days post fertilization. Morphant embryos displayed abnormal development of the eye, brain, heart, and muscle, as well as a 50 ± 22% decrease in ATP production. Transcriptome analysis revealed a decrease in protein-encoding transcripts from the heavy strand of the mtDNA, and down-regulation of genes involved in haem production and the metabolism of metabolites, which appear to trigger increased rRNA and tRNA synthesis in the nucleoli. However, this stress or compensatory response appears to fall short as pathology emerges and expression of genes related to eye development are severely down-regulated. Taken together, this study highlights the importance of sufficient mtDNA copies for early zebrafish development. Zebrafish is an excellent model to manipulate the mtDNA bottleneck and study its effect on embryogenesis rapidly and in large numbers of offspring.
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Affiliation(s)
- Auke B. C. Otten
- Department of Genetics and Cell Biology, Maastricht University, Maastricht, Netherlands
- Department of Dermatology, University of California, San Diego, La Jolla, CA, United States
- School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre, Maastricht, Netherlands
| | - Rick Kamps
- Department of Genetics and Cell Biology, Maastricht University, Maastricht, Netherlands
- School for Mental Health and Neurosciences (MHeNS), Maastricht University Medical Centre, Maastricht, Netherlands
| | - Patrick Lindsey
- Department of Genetics and Cell Biology, Maastricht University, Maastricht, Netherlands
- School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre, Maastricht, Netherlands
| | - Mike Gerards
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University Medical Centre, Maastricht, Netherlands
| | | | - Marc Muller
- Laboratory of Organogenesis and Regeneration, Univérsité Liège, Liège, Belgium
| | - Florence H. J. van Tienen
- Department of Genetics and Cell Biology, Maastricht University, Maastricht, Netherlands
- School for Mental Health and Neurosciences (MHeNS), Maastricht University Medical Centre, Maastricht, Netherlands
| | - Hubert J. M. Smeets
- Department of Genetics and Cell Biology, Maastricht University, Maastricht, Netherlands
- School for Oncology and Developmental Biology (GROW), Maastricht University Medical Centre, Maastricht, Netherlands
- School for Mental Health and Neurosciences (MHeNS), Maastricht University Medical Centre, Maastricht, Netherlands
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59
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Müller JS, Burns DT, Griffin H, Wells GR, Zendah RA, Munro B, Schneider C, Horvath R. RNA exosome mutations in pontocerebellar hypoplasia alter ribosome biogenesis and p53 levels. Life Sci Alliance 2020; 3:3/8/e202000678. [PMID: 32527837 PMCID: PMC7295610 DOI: 10.26508/lsa.202000678] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/01/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
The RNA exosome is a ubiquitously expressed complex of nine core proteins (EXOSC1-9) and associated nucleases responsible for RNA processing and degradation. Mutations in EXOSC3, EXOSC8, EXOSC9, and the exosome cofactor RBM7 cause pontocerebellar hypoplasia and motor neuronopathy. We investigated the consequences of exosome mutations on RNA metabolism and cellular survival in zebrafish and human cell models. We observed that levels of mRNAs encoding p53 and ribosome biogenesis factors are increased in zebrafish lines with homozygous mutations of exosc8 or exosc9, respectively. Consistent with higher p53 levels, mutant zebrafish have a reduced head size, smaller brain, and cerebellum caused by an increased number of apoptotic cells during development. Down-regulation of EXOSC8 and EXOSC9 in human cells leads to p53 protein stabilisation and G2/M cell cycle arrest. Increased p53 transcript levels were also observed in muscle samples from patients with EXOSC9 mutations. Our work provides explanation for the pathogenesis of exosome-related disorders and highlights the link between exosome function, ribosome biogenesis, and p53-dependent signalling. We suggest that exosome-related disorders could be classified as ribosomopathies.
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Affiliation(s)
- Juliane S Müller
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge, UK
| | - David T Burns
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Helen Griffin
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Graeme R Wells
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Romance A Zendah
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Benjamin Munro
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge, UK
| | - Claudia Schneider
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Rita Horvath
- Wellcome Trust Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK .,Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge, UK
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60
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EXOSC9 depletion attenuates P-body formation, stress resistance, and tumorigenicity of cancer cells. Sci Rep 2020; 10:9275. [PMID: 32518284 PMCID: PMC7283315 DOI: 10.1038/s41598-020-66455-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/21/2020] [Indexed: 01/16/2023] Open
Abstract
Cancer cells adapt to various stress conditions by optimizing gene expression profiles via transcriptional and translational regulation. However, whether and how EXOSC9, a component of the RNA exosome complex, regulates adaptation to stress conditions and tumorigenicity in cancer cells remain unclear. Here, we examined the effects of EXOSC9 depletion on cancer cell growth under various stress conditions. EXOSC9 depletion attenuated growth and survival under various stress conditions in cancer cells. Interestingly, this also decreased the number of P-bodies, which are messenger ribonucleoprotein particles (mRNPs) required for stress adaptation. Meanwhile, EXOSC2/EXOSC4 depletion also attenuated P-body formation and stress resistance with decreased EXOSC9 protein. EXOSC9-mediated stress resistance and P-body formation were found to depend on the intact RNA-binding motif of this protein. Further, RNA-seq analyses identified 343 EXOSC9-target genes, among which, APOBEC3G contributed to defects in stress resistance and P-body formation in MDA-MB-231 cells. Finally, EXOSC9 also promoted xenografted tumor growth of MDA-MB-231 cells in an intact RNA-binding motif-dependent manner. Database analyses further showed that higher EXOSC9 activity, estimated based on the expression of 343 target genes, was correlated with poorer prognosis in some cancer patients. Thus, drugs targeting activity of the RNA exosome complex or EXOSC9 might be useful for cancer treatment.
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61
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Lardelli RM, Lykke-Andersen J. Competition between maturation and degradation drives human snRNA 3' end quality control. Genes Dev 2020; 34:989-1001. [PMID: 32499401 PMCID: PMC7328512 DOI: 10.1101/gad.336891.120] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 04/29/2020] [Indexed: 12/11/2022]
Abstract
Polymerases and exonucleases act on 3' ends of nascent RNAs to promote their maturation or degradation but how the balance between these activities is controlled to dictate the fates of cellular RNAs remains poorly understood. Here, we identify a central role for the human DEDD deadenylase TOE1 in distinguishing the fates of small nuclear (sn)RNAs of the spliceosome from unstable genome-encoded snRNA variants. We found that TOE1 promotes maturation of all regular RNA polymerase II transcribed snRNAs of the major and minor spliceosomes by removing posttranscriptional oligo(A) tails, trimming 3' ends, and preventing nuclear exosome targeting. In contrast, TOE1 promotes little to no maturation of tested U1 variant snRNAs, which are instead targeted by the nuclear exosome. These observations suggest that TOE1 is positioned at the center of a 3' end quality control pathway that selectively promotes maturation and stability of regular snRNAs while leaving snRNA variants unprocessed and exposed to degradation in what could be a widespread mechanism of RNA quality control given the large number of noncoding RNAs processed by DEDD deadenylases.
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Affiliation(s)
- Rea M Lardelli
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - Jens Lykke-Andersen
- Division of Biological Sciences, University of California San Diego, La Jolla, California 92093, USA
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62
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Jedličková I, Přistoupilová A, Nosková L, Majer F, Stránecký V, Hartmannová H, Hodaňová K, Trešlová H, Hýblová M, Solár P, Minárik G, Giertlová M, Kmoch S. Spinal muscular atrophy caused by a novel Alu-mediated deletion of exons 2a-5 in SMN1 undetectable with routine genetic testing. Mol Genet Genomic Med 2020; 8:e1238. [PMID: 32337852 PMCID: PMC7336725 DOI: 10.1002/mgg3.1238] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 12/26/2022] Open
Abstract
Background Spinal muscular atrophy (SMA) is an inherited neuromuscular disease affecting 1 in 8,000 newborns. The majority of patients carry bi‐allelic variants in the survival of motor neuron 1 gene (SMN1). SMN1 is located in a duplicated region on chromosome 5q13 that contains Alu elements and is predisposed to genomic rearrangements. Due to the genomic complexity of the SMN region and genetic heterogeneity, approximately 50% of SMA patients remain without genetic diagnosis that is a prerequisite for genetic treatments. In this work we describe the diagnostic odyssey of one SMA patient in whom routine diagnostics identified only a maternal heterozygous SMN1Δ(7–8) deletion. Methods We characterized SMN transcripts, assessed SMN protein content in peripheral blood mononuclear cells (PBMC), estimated SMN genes dosage, and mapped genomic rearrangement in the SMN region. Results We identified an Alu‐mediated deletion encompassing exons 2a‐5 of SMN1 on the paternal allele and a complete deletion of SMN1 on the maternal allele as the cause of SMA in this patient. Conclusion Alu‐mediated rearrangements in SMN1 can escape routine diagnostic testing. Parallel analysis of SMN gene dosage, SMN transcripts, and total SMN protein levels in PBMC can identify genomic rearrangements and should be considered in genetically undefined SMA cases.
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Affiliation(s)
- Ivana Jedličková
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Anna Přistoupilová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Lenka Nosková
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Filip Majer
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Viktor Stránecký
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Hana Hartmannová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Kateřina Hodaňová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Helena Trešlová
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | | | - Peter Solár
- Department of Medical Biology, Faculty of Medicine, P.J. Safarik University, Kosice, Slovakia
| | - Gabriel Minárik
- Department of Clinical Genetics, Medirex A.S., Kosice, Slovakia
| | - Mária Giertlová
- Department of Clinical Genetics, Medirex A.S., Kosice, Slovakia
| | - Stanislav Kmoch
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
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63
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Regulation of long non-coding RNAs and genome dynamics by the RNA surveillance machinery. Nat Rev Mol Cell Biol 2020; 21:123-136. [PMID: 32020081 DOI: 10.1038/s41580-019-0209-0] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2019] [Indexed: 02/07/2023]
Abstract
Much of the mammalian genome is transcribed, generating long non-coding RNAs (lncRNAs) that can undergo post-transcriptional surveillance whereby only a subset of the non-coding transcripts is allowed to attain sufficient stability to persist in the cellular milieu and control various cellular functions. Paralleling protein turnover by the proteasome complex, lncRNAs are also likely to exist in a dynamic equilibrium that is maintained through constant monitoring by the RNA surveillance machinery. In this Review, we describe the RNA surveillance factors and discuss the vital role of lncRNA surveillance in orchestrating various biological processes, including the protection of genome integrity, maintenance of pluripotency of embryonic stem cells, antibody-gene diversification, coordination of immune cell activation and regulation of heterochromatin formation. We also discuss examples of human diseases and developmental defects associated with the failure of RNA surveillance mechanisms, further highlighting the importance of lncRNA surveillance in maintaining cell and organism functions and health.
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64
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de Amorim J, Slavotinek A, Fasken MB, Corbett AH, Morton DJ. Modeling Pathogenic Variants in the RNA Exosome. RNA & DISEASE 2020; 7:e1166. [PMID: 34676290 PMCID: PMC8528344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023] Open
Abstract
Exosomopathies are a collection of rare diseases caused by mutations in genes that encode structural subunits of the RNA exosome complex (EXOSC). The RNA exosome is critical for both processing and degrading many RNA targets. Mutations in individual RNA exosome subunit genes (termed EXOSC genes) are linked to a variety of distinct diseases. These exosomopathies do not arise from homozygous loss-of-function or large deletions in the EXOSC genes likely because some level of RNA exosome activity is essential for viability. Thus, all patients described so far have at least one allele with a missense mutation encoding an RNA exosome subunit with a single pathogenic amino acid change linked to disease. Understanding how these changes lead to the disparate clinical presentations that have been reported for this class of diseases necessitates investigation of how individual pathogenic missense variants alter RNA exosome function. Such studies will require access to patient samples, a challenge for these very rare diseases, coupled with modeling the patient variants. Here, we highlight five recent studies that model pathogenic variants in EXOSC3, EXOSC2, and EXOSC5.
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Affiliation(s)
- Julia de Amorim
- Department of Biology, Emory University,1510 Clifton Rd., NE RRC 1021, Atlanta, GA 30322, United States
- Graduate Program in Biochemistry, Cell, and Developmental Biology, Emory University,1510 Clifton Rd., NE RRC 1021, Atlanta, GA 30322, United States
| | - Anne Slavotinek
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94143, United States
| | - Milo B. Fasken
- Department of Biology, Emory University,1510 Clifton Rd., NE RRC 1021, Atlanta, GA 30322, United States
| | - Anita H. Corbett
- Department of Biology, Emory University,1510 Clifton Rd., NE RRC 1021, Atlanta, GA 30322, United States
| | - Derrick J. Morton
- The Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States
- Department of Biomedical Science, Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, CA 91101, United States
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Abstract
The evolutionarily conserved RNA exosome is a multisubunit ribonuclease complex that processes and/or degrades numerous RNAs. Recently, mutations in genes encoding both structural and catalytic subunits of the RNA exosome have been linked to human disease. Mutations in the structural exosome gene EXOSC2 cause a distinct syndrome that includes retinitis pigmentosa, hearing loss, and mild intellectual disability. In contrast, mutations in the structural exosome genes EXOSC3 and EXOSC8 cause pontocerebellar hypoplasia type 1b (PCH1b) and type 1c (PCH1c), respectively, which are related autosomal recessive, neurodegenerative diseases. In addition, mutations in the structural exosome gene EXOSC9 cause a PCH-like disease with cerebellar atrophy and spinal motor neuronopathy. Finally, mutations in the catalytic exosome gene DIS3 have been linked to multiple myeloma, a neoplasm of plasma B cells. How mutations in these RNA exosome genes lead to distinct, tissue-specific diseases is not currently well understood. In this chapter, we examine the role of the RNA exosome complex in human disease and discuss the mechanisms by which mutations in different exosome subunit genes could impair RNA exosome function and give rise to diverse diseases.
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Affiliation(s)
- Milo B Fasken
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA.
| | - Derrick J Morton
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
| | - Emily G Kuiper
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Stephanie K Jones
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA, USA
| | - Sara W Leung
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
| | - Anita H Corbett
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA.
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66
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Naef V, Mero S, Fichi G, D'Amore A, Ogi A, Gemignani F, Santorelli FM, Marchese M. Swimming in Deep Water: Zebrafish Modeling of Complicated Forms of Hereditary Spastic Paraplegia and Spastic Ataxia. Front Neurosci 2019; 13:1311. [PMID: 31920481 PMCID: PMC6914767 DOI: 10.3389/fnins.2019.01311] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 11/22/2019] [Indexed: 12/13/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) and hereditary ataxia (HA) are two groups of disorders characterized, respectively, by progressive dysfunction or degeneration of the pyramidal tracts (HSP) and of the Purkinje cells and spinocerebellar tracts (HA). Although HSP and HA are generally shown to have distinct clinical-genetic profiles, in several cases the clinical presentation, the causative genes, and the cellular pathways and mechanisms involved overlap between the two forms. Genetic analyses in humans in combination with in vitro and in vivo studies using model systems have greatly expanded our knowledge of spinocerebellar degenerative disorders. In this review, we focus on the zebrafish (Danio rerio), a vertebrate model widely used in biomedical research since its overall nervous system organization is similar to that of humans. A critical analysis of the literature suggests that zebrafish could serve as a powerful experimental tool for molecular and genetic dissection of both HA and HSP. The zebrafish, found to be very useful for demonstrating the causal relationship between defect and mutation, also offers a useful platform to exploit for the development of therapies.
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Affiliation(s)
- Valentina Naef
- Neurobiology and Molecular Medicine, IRCCS Stella Maris, Pisa, Italy
| | - Serena Mero
- Neurobiology and Molecular Medicine, IRCCS Stella Maris, Pisa, Italy.,Department of Biology, University of Pisa, Pisa, Italy
| | - Gianluca Fichi
- Neurobiology and Molecular Medicine, IRCCS Stella Maris, Pisa, Italy.,Struttura Complessa Toscana Sud (Sede Grosseto), Istituto Zooprofilattico Sperimentale del Lazio e Toscana M. Aleandri, Grosseto, Italy
| | - Angelica D'Amore
- Neurobiology and Molecular Medicine, IRCCS Stella Maris, Pisa, Italy.,Department of Biology, University of Pisa, Pisa, Italy.,Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
| | - Asahi Ogi
- Neurobiology and Molecular Medicine, IRCCS Stella Maris, Pisa, Italy.,Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | | | - Maria Marchese
- Neurobiology and Molecular Medicine, IRCCS Stella Maris, Pisa, Italy
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Pontocerebellar hypoplasia with rhombencephalosynapsis and microlissencephaly expands the spectrum of PCH type 1B. Eur J Med Genet 2019; 63:103814. [PMID: 31770597 DOI: 10.1016/j.ejmg.2019.103814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/14/2019] [Accepted: 11/11/2019] [Indexed: 11/20/2022]
Abstract
Rhombencephalosynapsis is a rare cerebellar malformation developing during embryogenesis defined by vermian agenesis or hypogenesis with fusion of the cerebellar hemispheres. It occurs either alone or in association with other cerebral and/or extracerebral anomalies. Its association with microlissencephaly is exceedingly rare and to date, only a heterozygous de novo missense variant in ADGRL2, a gene encoding Adhesion G-Protein-Coupled Receptor L2, has been identified. We report on two siblings of Roma origin presenting with severe growth retardation, fetal akinesia, microlissencephaly and small cerebellum with vermian agenesis. Neuropathological studies revealed extreme paucity in pontine transverse fibres, rudimentary olivary nuclei and rhombencephalosynapsis with vanishing spinal motoneurons in both fetuses. Comparative fetus-parent exome sequencing revealed in both fetuses a homozygous variant in exon 1 of the EXOSC3 gene encoding a core component of the RNA exosome, c.92G > C; p.(Gly31Ala). EXOSC3 accounts for 40%-75% of patients affected by ponto-cerebellar hypoplasia with spinal muscular atrophy (PCH1B). The c.92G > C variant is a founder mutation in the Roma population and has been reported in severe PCH1B. PCH1B is characterized by a broad phenotypic spectrum, ranging from mild phenotypes with spasticity, mild to moderate intellectual disability, pronounced distal muscular and cerebellar atrophy/hypoplasia, to severe phenotypes with profound global developmental delay, progressive microcephaly and atrophy of the cerebellar hemispheres. In PCH1B, the usual cerebellar lesions affect mainly the hemispheres with relative sparing of vermis that radically differs from rhombencephalosynapsis. This unusual foetal presentation expands the spectrum of PCH1B and highlights the diversity of rhombencephalosynapsis etiologies.
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68
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Zhang W, Zhu J, He X, Liu X, Li J, Li W, Yang P, Wang J, Hu K, Zhang X, Li X, Jing H. Exosome complex genes mediate RNA degradation and predict survival in mantle cell lymphoma. Oncol Lett 2019; 18:5119-5128. [PMID: 31612023 PMCID: PMC6781731 DOI: 10.3892/ol.2019.10850] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 07/26/2019] [Indexed: 11/06/2022] Open
Abstract
Exosome complex (EXOSC) genes, which encode a multi-protein intracellular complex, mediate the degradation of various types of RNA molecules. EXOSCs, also known as polymyositis/scleroderma complexes, exist in eukaryotic cells and archaea, and primarily mediate 3′ to 5′mRNA degradation. However, how EXOSC genes are implicated in processes of B-cell immune-associated pathways and B-cell tumorigenesis remains unclear. The present bioinformatics study indicated that 6 of 10 EXOSC genes, particularly the EXO.index, were able to predict the survival of patients with mantle cell lymphoma (MCL), by analyzing gene expression profiles of 123 patients with MCL from the Gene Expression Omnibus database. The results suggested that EXOSC gene expression may be a molecular marker for MCL. Compared with the whole transcript profile, patients with MCL with a high EXO.index exhibited poorer survival and decreased RNA levels, which was also verified in a second dataset. The EXOSC genes may be associated with DNA repair and B-cell activation pathways, which may be the cause of poorer survival of patients with MCL.
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Affiliation(s)
- Weilong Zhang
- Department of Hematology, Lymphoma Research Center, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Junyong Zhu
- Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing 100853, P.R. China
| | - Xue He
- Department of Pathology, Beijing Tiantan Hospital Affiliated with Capital Medical University, Beijing 100050, P.R. China
| | - Xiaoni Liu
- Department of Respiratory Medicine, The First Affiliated Hospital of Gannan Medical University, Ganzhou, Guangdong 341000, P.R. China
| | - Jinhang Li
- Department of Pathology, Chinese People's Liberation Army General Hospital, Beijing 100853, P.R. China
| | - Wei Li
- Department of Hematology, Lymphoma Research Center, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Ping Yang
- Department of Hematology, Lymphoma Research Center, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Jing Wang
- Department of Hematology, Lymphoma Research Center, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Kai Hu
- Department of Hematology, Lymphoma Research Center, Peking University Third Hospital, Beijing 100191, P.R. China
| | - Xiuru Zhang
- Department of Pathology, Beijing Tiantan Hospital Affiliated with Capital Medical University, Beijing 100050, P.R. China
| | - Xiru Li
- Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing 100853, P.R. China
| | - Hongmei Jing
- Department of Hematology, Lymphoma Research Center, Peking University Third Hospital, Beijing 100191, P.R. China
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69
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Fu CZ, Guang XM, Wan QH, Fang SG. Genome Resequencing Reveals Congenital Causes of Embryo and Nestling Death in Crested Ibis (Nipponia nippon). Genome Biol Evol 2019; 11:2125-2135. [PMID: 31298688 PMCID: PMC6685491 DOI: 10.1093/gbe/evz149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/14/2019] [Indexed: 12/18/2022] Open
Abstract
The crested ibis (Nipponia nippon) is endangered worldwide. Although a series of conservation measures have markedly increased the population size and distribution area of these birds, the high mortality of embryos and nestlings considerably decreases the survival potential of this bird species. High-throughput sequencing technology was utilized to compare whole genomes between ten samples from dead crested ibises (including six dead embryos and four dead nestlings aged 0-45 days) and 32 samples from living birds. The results indicated that the dead samples all shared the genetic background of a specific ancestral subpopulation. Furthermore, the dead individuals were less genetically diverse and suffered higher degrees of inbreeding compared with these measures in live birds. Several candidate genes (KLHL3, SETDB2, TNNT2, PKP1, AK1, and EXOSC3) associated with detrimental diseases were identified in the genomic regions that differed between the alive and dead samples, which are likely responsible for the death of embryos and nestlings. In addition, in these regions, we also found several genes involved in the protein catabolic process (UBE4A and LONP1), lipid metabolism (ACOT1), glycan biosynthesis and metabolism (HYAL1 and HYAL4), and the immune system (JAM2) that are likely to promote the normal development of embryos and nestlings. The aberrant conditions of these genes and biological processes may contribute to the death of embryos and nestlings. Our data identify congenital factors underlying the death of embryos and nestlings at the whole genome level, which may be useful toward informing more effective conservation efforts for this bird species.
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Affiliation(s)
- Chun-Zheng Fu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Xuan-Min Guang
- MOE Key Laboratory of Biosystems Homeostasis & Protection, State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Qiu-Hong Wan
- MOE Key Laboratory of Biosystems Homeostasis & Protection, State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou, P.R. China
| | - Sheng-Guo Fang
- MOE Key Laboratory of Biosystems Homeostasis & Protection, State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou, P.R. China
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70
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Telekawa C, Boisvert FM, Bachand F. Proteomic profiling and functional characterization of post-translational modifications of the fission yeast RNA exosome. Nucleic Acids Res 2019; 46:11169-11183. [PMID: 30321377 PMCID: PMC6265454 DOI: 10.1093/nar/gky915] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/11/2018] [Indexed: 12/11/2022] Open
Abstract
The RNA exosome is a conserved multi-subunit complex essential for processing and degradation of several types of RNAs. Although many of the functions of the RNA exosome are well established, whether the activity of this complex is regulated remains unclear. Here we performed a proteomic analysis of the RNA exosome complex purified from Schizosaccharomyces pombe and identified 39 post-translational modifications (PTMs), including phosphorylation, methylation, and acetylation sites. Interestingly, most of the modifications were identified in Dis3, a catalytic subunit of the RNA exosome, as well as in the exosome-associated RNA helicase, Mtr4. Functional analysis of selected PTM sites using modification-deficient and -mimetic versions of exosome subunits revealed substitutions that affected cell growth and exosome functions. Notably, our results suggest that site-specific phosphorylation in the catalytic center of Dis3 and in the helical bundle domain of Mtr4 control their activity. Our findings support a view in which post-translational modifications fine-tune exosome activity and add a layer of regulation to RNA degradation.
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Affiliation(s)
- Caroline Telekawa
- RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, QC, Canada
| | | | - François Bachand
- RNA Group, Department of Biochemistry, Université de Sherbrooke, Sherbrooke, QC, Canada
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71
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Gordon J, Pillon MC, Stanley RE. Nol9 Is a Spatial Regulator for the Human ITS2 Pre-rRNA Endonuclease-Kinase Complex. J Mol Biol 2019; 431:3771-3786. [PMID: 31288032 DOI: 10.1016/j.jmb.2019.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/01/2022]
Abstract
The ribosome plays a universal role in translating the cellular proteome. Defects in the ribosome assembly factor Las1L are associated with congenital lethal motor neuron disease and X-linked intellectual disability disorders, yet its role in processing precursor ribosomal RNA (pre-rRNA) is largely unclear. The Las1L endoribonuclease associates with the Nol9 polynucleotide kinase to form the internal transcribed spacer 2 (ITS2) pre-rRNA endonuclease-kinase machinery. Together, Las1L-Nol9 catalyzes RNA cleavage and phosphorylation to mark the ITS2 for degradation. While ITS2 processing is critical for the production of functional ribosomes, the regulation of mammalian Las1L-Nol9 remains obscure. Here we characterize the human Las1L-Nol9 complex and identify critical molecular features that regulate its assembly and spatial organization. We establish that Las1L and Nol9 form a higher-order complex and identify the regions responsible for orchestrating this intricate architecture. Structural analysis by high-resolution imaging defines the intricate spatial pattern of Las1L-Nol9 within the nucleolar sub-structure linked with late pre-rRNA processing events. Furthermore, we uncover a Nol9-encoded nucleolar localization sequence that is responsible for nucleolar transport of the assembled Las1L-Nol9 complex. Together, these data provide a mechanism for the assembly and nucleolar localization of the human ITS2 pre-rRNA endonuclease-kinase complex.
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Affiliation(s)
- Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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72
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van Dijk T, Rudnik-Schöneborn S, Senderek J, Hajmousa G, Mei H, Dusl M, Aronica E, Barth P, Baas F. Pontocerebellar hypoplasia with spinal muscular atrophy (PCH1): identification of SLC25A46 mutations in the original Dutch PCH1 family. Brain 2019. [PMID: 28637197 DOI: 10.1093/brain/awx147] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Tessa van Dijk
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Sabine Rudnik-Schöneborn
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria.,Institute of Human Genetics, RWTH Aachen University, Aachen, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Ghazaleh Hajmousa
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands
| | - Hailiang Mei
- Sequencing Analysis Support Core, Leiden University Medical Center, Leiden, The Netherlands
| | - Marina Dusl
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Eleonora Aronica
- Department of (Neuro) Pathology, Academic Medical Center, Amsterdam, The Netherlands
| | - Peter Barth
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
| | - Frank Baas
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands.,Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Karakaya M, Paketci C, Altmueller J, Thiele H, Hoelker I, Yis U, Wirth B. Biallelic variant in AGTPBP1 causes infantile lower motor neuron degeneration and cerebellar atrophy. Am J Med Genet A 2019; 179:1580-1584. [PMID: 31102495 DOI: 10.1002/ajmg.a.61198] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/03/2019] [Accepted: 05/05/2019] [Indexed: 11/08/2022]
Abstract
Infantile hereditary lower motor neuron disorders beyond 5q-spinal muscular atrophy (5q-SMA) are usually caused by mutations other than deletions or mutations in SMN1. In addition to motor neuron degeneration, further neurologic or multisystemic pathologies in non-5q-SMAs are not seldom. Some of the non-5q-SMA phenotypes, such as pontocerebellar hypoplasia (PCH1), have been classified later as a different disease group due to distinctive primary pathologies. Likewise, a novel phenotype, childhood-onset neurodegeneration with cerebellar atrophy (CONDCA) has been described recently in individuals with lower motor neuron disorder and cerebellar atrophy due to biallelic loss-of-function variants in AGTPBP1 that encodes cytosolic carboxypeptidase 1 (CCP1). Here we present two individuals with CONDCA in whom a biallelic missense AGTPBP1 variant (NM_001330701.1:c.2396G>T, p.Arg799Leu) was identified by whole exome sequencing. Affected individuals in this report correspond to the severe infantile spectrum of the disease and underline the severe pathogenic effect of this missense variant. This report is the second in the literature that delineates the pathogenic effects of biallelic AGTPBP1 variants presenting the recently described CONDCA disease.
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Affiliation(s)
- Mert Karakaya
- Institute of Human Genetics, Center for Molecular Medicine Cologne (CMMC), Institute of Genetics, and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany
| | - Cem Paketci
- Department of Pediatric Neurology, Dokuz Eylül University, Izmir, Turkey
| | - Janine Altmueller
- Institute of Human Genetics, Center for Molecular Medicine Cologne (CMMC), Institute of Genetics, and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany.,Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Irmgard Hoelker
- Institute of Human Genetics, Center for Molecular Medicine Cologne (CMMC), Institute of Genetics, and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany
| | - Uluc Yis
- Department of Pediatric Neurology, Dokuz Eylül University, Izmir, Turkey
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne (CMMC), Institute of Genetics, and Center for Rare Diseases Cologne, University of Cologne, Cologne, Germany
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Le Duc D, Horn S, Jamra RA, Schaper J, Wieczorek D, Redler S. Novel EXOSC3 pathogenic variant results in a mild course of neurologic disease with cerebellum involvement. Eur J Med Genet 2019; 63:103649. [PMID: 30986545 DOI: 10.1016/j.ejmg.2019.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 03/21/2019] [Accepted: 04/04/2019] [Indexed: 10/27/2022]
Abstract
EXOSC3-related autosomal recessive neurodevelopmental disorders are rare entities with variable clinical course and prognosis. They are characterized by hypoplasia of cerebellar structures and pons, degeneration of the anterior horn cells and motor as well as neurocognitive impairment. Phenotypic expression is variable with an overall poor outcome. Current research suggests clear genotype-phenotype correlations among EXOSC3-pathogenic-variants carriers. Homozygosity for the EXOSC3 variant c.395A > C, p.(Asp132Ala) is proposed to lead to a rather mild phenotype compared to compound-heterozygous EXOSC3-pathogenic-variants carriers with lethal neurological disease in very early childhood. In this study, we report two siblings (21- and 8-year-old) affected by PCH1B with an unusual presentation. We identified compound heterozygosity for the well-established EXOSC3 variant c.395A > C, p.(Asp132Ala) and the novel variant c.572G > A, p.(Gly191Asp), expanding the genetic spectrum. Phenotypic presentation of the siblings was strikingly different from that of literature reports with a surprisingly mild disease manifestation and an unexpected intrafamilial variability. This study demonstrates the extensive clinical heterogeneity and the broad phenotypic spectrum associated with EXOSC3-associated disorders. Enlargement of sample sizes and reports of novel cases will be essential for the delineation of associated phenotypes.
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Affiliation(s)
- Diana Le Duc
- Institute of Human Genetics, University of Leipzig, Leipzig, Germany
| | - Susanne Horn
- Institute of Human Genetics, University of Leipzig, Leipzig, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University of Leipzig, Leipzig, Germany
| | - Jörg Schaper
- Heinrich-Heine-University, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf, Germany
| | - Dagmar Wieczorek
- Heinrich-Heine-University, Medical Faculty, Institute of Human Genetics, Düsseldorf, Germany
| | - Silke Redler
- Heinrich-Heine-University, Medical Faculty, Institute of Human Genetics, Düsseldorf, Germany; Heinrich-Heine-University, Medical Faculty, Center of Rare Disorders, Düsseldorf, Germany.
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75
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Biallelic variants in AGTPBP1, involved in tubulin deglutamylation, are associated with cerebellar degeneration and motor neuropathy. Eur J Hum Genet 2019; 27:1419-1426. [PMID: 30976113 DOI: 10.1038/s41431-019-0400-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 03/16/2019] [Accepted: 03/26/2019] [Indexed: 11/08/2022] Open
Abstract
The ATP/GTP-Binding Protein 1 (AGTPBP1) gene (OMIM *606830) catalyzes deglutamylation of polyglutamylated proteins, and its deficiency manifests by cerebellar ataxia and peripheral neuropathy in mice and lower motor neuron-like disease in sheep. In the mutant mice, cerebellar atrophy due to Purkinje cell degeneration is observed, likely due to increased tubulin polyglutamylation in affected brain areas. We report two unrelated individuals who presented with early onset cerebellar atrophy, developmental arrest with progressive muscle weakness, and feeding and respiratory difficulties, accompanied by severe motor neuronopathy. Whole exome sequencing followed by segregation analysis in the families and cDNA studies revealed deleterious biallelic variants in the AGTPBP1 gene. We conclude that complete loss-of-function of AGTPBP1 in humans, just like in mice and sheep, is associated with cerebellar and motor neuron disease, reminiscent of Pontocerebellar Hypoplasia Type 1 (PCH1).
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76
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Disruption of Telomerase RNA Maturation Kinetics Precipitates Disease. Mol Cell 2019; 74:688-700.e3. [PMID: 30930056 DOI: 10.1016/j.molcel.2019.02.033] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 01/07/2019] [Accepted: 02/21/2019] [Indexed: 01/16/2023]
Abstract
Mutations in RNA-processing enzymes are increasingly linked to human disease. Telomerase RNA and related noncoding RNAs require 3' end-processing steps, including oligoadenylation. Germline mutations in poly(A)ribonuclease (PARN) cause accumulation of extended human telomerase RNA (hTR) species and precipitate dyskeratosis congenita and pulmonary fibrosis. Here, we develop nascent RNAend-seq to measure processing rates of RNA precursors. We find that mature hTR derives from extended precursors but that in PARN-mutant cells hTR maturation kinetically stalls and unprocessed precursors are degraded. Loss of poly(A)polymerase PAPD5 in PARN-mutant cells accelerates hTR maturation and restores hTR processing, indicating that oligoadenylation and deadenylation set rates of hTR maturation. The H/ACA domain mediates hTR maturation by precisely defining the 3' end, recruiting poly(A)polymerase activity, and conferring sensitivity to PARN regulation. These data reveal a feedforward circuit in which post-transcriptional oligoadenylation controls RNA maturation kinetics. Similar alterations in RNA processing rates may contribute to mechanisms of RNA-based human disease.
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77
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Helicase-Dependent RNA Decay Illuminated by a Cryo-EM Structure of a Human Nuclear RNA Exosome-MTR4 Complex. Cell 2019; 173:1663-1677.e21. [PMID: 29906447 DOI: 10.1016/j.cell.2018.05.041] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 01/08/2023]
Abstract
The ribonucleolytic RNA exosome interacts with RNA helicases to degrade RNA. To understand how the 3' to 5' Mtr4 helicase engages RNA and the nuclear exosome, we reconstituted 14-subunit Mtr4-containing RNA exosomes from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and human and show that they unwind structured substrates to promote degradation. We loaded a human exosome with an optimized DNA-RNA chimera that stalls MTR4 during unwinding and determined its structure to an overall resolution of 3.45 Å by cryoelectron microscopy (cryo-EM). The structure reveals an RNA-engaged helicase atop the non-catalytic core, with RNA captured within the central channel and DIS3 exoribonuclease active site. MPP6 tethers MTR4 to the exosome through contacts to the RecA domains of MTR4. EXOSC10 remains bound to the core, but its catalytic module and cofactor C1D are displaced by RNA-engaged MTR4. Competition for the exosome core may ensure that RNA is committed to degradation by DIS3 when engaged by MTR4.
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78
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Tuorto F, Parlato R. rRNA and tRNA Bridges to Neuronal Homeostasis in Health and Disease. J Mol Biol 2019; 431:1763-1779. [PMID: 30876917 DOI: 10.1016/j.jmb.2019.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 12/11/2022]
Abstract
Dysregulation of protein translation is emerging as a unifying mechanism in the pathogenesis of many neuronal disorders. Ribosomal RNA (rRNA) and transfer RNA (tRNA) are structural molecules that have complementary and coordinated functions in protein synthesis. Defects in both rRNAs and tRNAs have been described in mammalian brain development, neurological syndromes, and neurodegeneration. In this review, we present the molecular mechanisms that link aberrant rRNA and tRNA transcription, processing and modifications to translation deficits, and neuropathogenesis. We also discuss the interdependence of rRNA and tRNA biosynthesis and how their metabolism brings together proteotoxic stress and impaired neuronal homeostasis.
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Affiliation(s)
- Francesca Tuorto
- Division of Epigenetics, DKFZ-ZMBH Alliance, German Cancer Research Center, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany.
| | - Rosanna Parlato
- Institute of Applied Physiology, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany; Institute of Anatomy and Cell Biology, Medical Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, 69120 Heidelberg, Germany.
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79
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Peck SA, Hughes KD, Victorino JF, Mosley AL. Writing a wrong: Coupled RNA polymerase II transcription and RNA quality control. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1529. [PMID: 30848101 PMCID: PMC6570551 DOI: 10.1002/wrna.1529] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/27/2018] [Accepted: 02/07/2019] [Indexed: 12/20/2022]
Abstract
Processing and maturation of precursor RNA species is coupled to RNA polymerase II transcription. Co-transcriptional RNA processing helps to ensure efficient and proper capping, splicing, and 3' end processing of different RNA species to help ensure quality control of the transcriptome. Many improperly processed transcripts are not exported from the nucleus, are restricted to the site of transcription, and are in some cases degraded, which helps to limit any possibility of aberrant RNA causing harm to cellular health. These critical quality control pathways are regulated by the highly dynamic protein-protein interaction network at the site of transcription. Recent work has further revealed the extent to which the processes of transcription and RNA processing and quality control are integrated, and how critically their coupling relies upon the dynamic protein interactions that take place co-transcriptionally. This review focuses specifically on the intricate balance between 3' end processing and RNA decay during transcription termination. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Processing > 3' End Processing RNA Processing > Splicing Mechanisms RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Sarah A Peck
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Katlyn D Hughes
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jose F Victorino
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
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80
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Laffleur B, Basu U. Biology of RNA Surveillance in Development and Disease. Trends Cell Biol 2019; 29:428-445. [PMID: 30755352 DOI: 10.1016/j.tcb.2019.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/03/2019] [Accepted: 01/10/2019] [Indexed: 01/09/2023]
Abstract
The 'RNA world', in which RNA molecules stored information and acquired enzymatic properties, has been proposed to have preceded organism life. RNA is now recognized for its central role in biology, with accumulating evidence implicating coding and noncoding (nc)RNAs in myriad mechanisms regulating cellular physiology and disequilibrium in transcriptomes resulting in pathological conditions. Nascently synthesized RNAs are subjected to stringent regulation by sophisticated RNA surveillance pathways. In this review, we integrate these pathways from a developmental viewpoint, proposing RNA surveillance as the convergence of mechanisms that ensure the exact titration of RNA molecules in a spatiotemporally controlled manner, leading to development without the onset of pathological conditions, including cancer.
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Affiliation(s)
- Brice Laffleur
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
| | - Uttiya Basu
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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81
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Pinto MM, Monges S, Malfatti E, Lubieniecki F, Lornage X, Alias L, Labasse C, Madelaine A, Fardeau M, Laporte J, Tizzano EF, Romero NB. Sarcomeric disorganization and nemaline bodies in muscle biopsies of patients with EXOSC3-related type 1 pontocerebellar hypoplasia. Muscle Nerve 2018; 59:137-141. [PMID: 30025162 DOI: 10.1002/mus.26305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2018] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Mutations in the EXOSC3 gene are responsible for type 1 pontocerebellar hypoplasia, an autosomal recessive congenital disorder characterized by cerebellar atrophy, developmental delay, and anterior horn motor neuron degeneration. Muscle biopsies of these patients often show characteristics resembling classic spinal muscle atrophy, but to date, no distinct features have been identified. METHODS Clinical data and muscle biopsy findings of 3 unrelated patients with EXOSC3 mutations are described. RESULTS All patients presented as a severe congenital cognitive and neuromuscular phenotype with short survival, harboring the same point mutation (c.92G>C; p.Gly31Ala). Muscle biopsies consistently showed variable degrees of sarcomeric disorganization with myofibrillar remnants, Z-line thickening, and small nemaline bodies. CONCLUSIONS In this uniform genetic cohort of patients with EXOSC3 mutations, sarcomeric disruption and rod structures were prominent features of muscle biopsies. In the context of neonatal hypotonia, ultrastructural studies might provide early clues for the diagnosis of EXOSC3-related pontocerebellar hypoplasia. Muscle Nerve 59:137-141, 2019.
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Affiliation(s)
- Miguel M Pinto
- Neurology Department, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal
| | - Soledad Monges
- Neuropediatric and Neuropathology Departments, National Pediatric Hospital J-P-Garrahan, Buenos Aires, Argentina
| | - Edoardo Malfatti
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne University, INSERM UMR 974, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, 75013, Paris, France
| | - Fabiana Lubieniecki
- Neuropediatric and Neuropathology Departments, National Pediatric Hospital J-P-Garrahan, Buenos Aires, Argentina
| | - Xavière Lornage
- Department of Translational Medicine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), INSERM U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France
| | - Laura Alias
- Department of Genetics, Hospital Sant Pau and CIBERER, Barcelona, Spain
| | - Clémence Labasse
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne University, INSERM UMR 974, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, 75013, Paris, France
| | - Angéline Madelaine
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne University, INSERM UMR 974, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, 75013, Paris, France
| | - Michel Fardeau
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne University, INSERM UMR 974, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, 75013, Paris, France
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, IGBMC (Institut de Génétique et de Biologie Moléculaire et Cellulaire), INSERM U1258, CNRS UMR7104, Université de Strasbourg, Illkirch, France
| | - Eduardo F Tizzano
- Department of Clinical and Molecular Genetics and Rare Diseases Division, Hospital Vall d'Hebron and CIBERER, Barcelona, Spain
| | - Norma B Romero
- Unité de Morphologie Neuromusculaire, Institut de Myologie, Sorbonne University, INSERM UMR 974, Groupe Hospitalier Universitaire La Pitié-Salpêtrière, 75013, Paris, France
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82
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Zhou J, Chen L, Chen B, Huang S, Zeng C, Wu H, Chen C, Long F. Increased serum exosomal miR-134 expression in the acute ischemic stroke patients. BMC Neurol 2018; 18:198. [PMID: 30514242 PMCID: PMC6278025 DOI: 10.1186/s12883-018-1196-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 11/06/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The exosomal miRNAs have been emerged as biomarkers and therapeutic targets for various diseases, however, the function of exosomal miRNAs in stroke remains largely unknown. METHODS The blood samples from acute ischemic stroke (AIS) patients and normal controls were collected. The exosomes were isolated from the blood samples, which were confirmed by electron microscopy and western blot with the specific exosomes biomarker CD9, CD63 and Tsg101. RESULTS RT-qPCR analysis showed that exosomal miR-134 was significantly increased in AIS patients within 24 h after stroke onset compared with that of control group. Highly expressed exosomal miR-134 was correlated with the National Institutes of Health Stroke Scale (NIHSS) scores, infarct volume and positively associated with the worse prognosis of the stroke patients. Additionally, the exosomal miR-134 was strong positively correlated with the expression of serum interleukin 6 (IL-6) and plasma high-sensitivity C relative protein (hs-CRP). The receiver operating characteristic (ROC) curve suggested that miR-134 might be a potential factor to discriminate AIS patients from non-stroke controls. CONCLUSIONS The exosomal miR-134 as a possible novel biomarker for the diagnosis and prognosis of stroke.
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Affiliation(s)
- Jingxia Zhou
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Lin Chen
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Bocan Chen
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Shaozhu Huang
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Chaosheng Zeng
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Hairong Wu
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Cong Chen
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China
| | - Faqing Long
- Department of Neurology, The Second Affiliated Hospital of Hainan Medical University, Haikou, 570311, Hainan Province, People's Republic of China.
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83
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Hetman M, Slomnicki LP. Ribosomal biogenesis as an emerging target of neurodevelopmental pathologies. J Neurochem 2018; 148:325-347. [PMID: 30144322 DOI: 10.1111/jnc.14576] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/15/2018] [Accepted: 08/21/2018] [Indexed: 12/17/2022]
Abstract
Development of the nervous system is carried out by complex gene expression programs that are regulated at both transcriptional and translational level. In addition, quality control mechanisms such as the TP53-mediated apoptosis or neuronal activity-stimulated survival ensure successful neurogenesis and formation of functional circuitries. In the nucleolus, production of ribosomes is essential for protein synthesis. In addition, it participates in chromatin organization and regulates the TP53 pathway via the ribosomal stress response. Its tight regulation is required for maintenance of genomic integrity. Mutations in several ribosomal components and trans-acting ribosomal biogenesis factors result in neurodevelopmental syndromes that present with microcephaly, autism, intellectual deficits and/or progressive neurodegeneration. Furthermore, ribosomal biogenesis is perturbed by exogenous factors that disrupt neurodevelopment including alcohol or Zika virus. In this review, we present recent literature that argues for a role of dysregulated ribosomal biogenesis in pathogenesis of various neurodevelopmental syndromes. We also discuss potential mechanisms through which such dysregulation may lead to cellular pathologies of the developing nervous system including insufficient proliferation and/or loss of neuroprogenitors cells, apoptosis of immature neurons, altered neuronal morphogenesis, and neurodegeneration.
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Affiliation(s)
- Michal Hetman
- Departments of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA.,Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Lukasz P Slomnicki
- Departments of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
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84
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François-Moutal L, Jahanbakhsh S, Nelson ADL, Ray D, Scott DD, Hennefarth MR, Moutal A, Perez-Miller S, Ambrose AJ, Al-Shamari A, Coursodon P, Meechoovet B, Reiman R, Lyons E, Beilstein M, Chapman E, Morris QD, Van Keuren-Jensen K, Hughes TR, Khanna R, Koehler C, Jen J, Gokhale V, Khanna M. A Chemical Biology Approach to Model Pontocerebellar Hypoplasia Type 1B (PCH1B). ACS Chem Biol 2018; 13:3000-3010. [PMID: 30141626 DOI: 10.1021/acschembio.8b00745] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mutations of EXOSC3 have been linked to the rare neurological disorder known as Pontocerebellar Hypoplasia type 1B (PCH1B). EXOSC3 is one of three putative RNA-binding structural cap proteins that guide RNA into the RNA exosome, the cellular machinery that degrades RNA. Using RNAcompete, we identified a G-rich RNA motif binding to EXOSC3. Surface plasmon resonance (SPR) and microscale thermophoresis (MST) indicated an affinity in the low micromolar range of EXOSC3 for long and short G-rich RNA sequences. Although several PCH1B-causing mutations in EXOSC3 did not engage a specific RNA motif as shown by RNAcompete, they exhibited lower binding affinity to G-rich RNA as demonstrated by MST. To test the hypothesis that modification of the RNA-protein interface in EXOSC3 mutants may be phenocopied by small molecules, we performed an in-silico screen of 50 000 small molecules and used enzyme-linked immunosorbant assays (ELISAs) and MST to assess the ability of the molecules to inhibit RNA-binding by EXOSC3. We identified a small molecule, EXOSC3-RNA disrupting (ERD) compound 3 (ERD03), which ( i) bound specifically to EXOSC3 in saturation transfer difference nuclear magnetic resonance (STD-NMR), ( ii) disrupted the EXOSC3-RNA interaction in a concentration-dependent manner, and ( iii) produced a PCH1B-like phenotype with a 50% reduction in the cerebellum and an abnormally curved spine in zebrafish embryos. This compound also induced modification of zebrafish RNA expression levels similar to that observed with a morpholino against EXOSC3. To our knowledge, this is the first example of a small molecule obtained by rational design that models the abnormal developmental effects of a neurodegenerative disease in a whole organism.
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Affiliation(s)
- Liberty François-Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
- Center for Innovation in Brain Science, Tucson, Arizona 85721, United States
| | - Shahriyar Jahanbakhsh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Andrew D. L. Nelson
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Debashish Ray
- Donnelly Centre, University of Toronto, Toronto, Canada M5S 3E1
| | - David D. Scott
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
- Center for Innovation in Brain Science, Tucson, Arizona 85721, United States
| | - Matthew R. Hennefarth
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Aubin Moutal
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
| | - Samantha Perez-Miller
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
- Center for Innovation in Brain Science, Tucson, Arizona 85721, United States
| | - Andrew J. Ambrose
- Pharmacology and Toxicology, School of Pharmacy, University of Arizona, Tucson, Arizona 85724, United States
| | - Ahmed Al-Shamari
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
| | - Philippe Coursodon
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
| | | | - Rebecca Reiman
- Neurogenomics Division, TGen, Phoenix, Arizona 85004, United States
| | - Eric Lyons
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Mark Beilstein
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, United States
| | - Eli Chapman
- Pharmacology and Toxicology, School of Pharmacy, University of Arizona, Tucson, Arizona 85724, United States
| | - Quaid D. Morris
- Donnelly Centre, University of Toronto, Toronto, Canada M5S 3E1
- Department of Molecular Genetics, University of Toronto, Toronto, Canada M5S 1A8
- Department of Computer Science, University of Toronto, Toronto, Canada M5S 2E4
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada M5S3G4
| | | | - Timothy R. Hughes
- Donnelly Centre, University of Toronto, Toronto, Canada M5S 3E1
- Department of Molecular Genetics, University of Toronto, Toronto, Canada M5S 1A8
| | - Rajesh Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
- Center for Innovation in Brain Science, Tucson, Arizona 85721, United States
| | - Carla Koehler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Joanna Jen
- Mount Sinai, New York, New York 10029, United States
| | - Vijay Gokhale
- Bio5 Institute, University of Arizona, Tucson, Arizona, United States
| | - May Khanna
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724, United States
- Center for Innovation in Brain Science, Tucson, Arizona 85721, United States
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85
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Calhoun JD, Carvill GL. Unravelling the genetic architecture of autosomal recessive epilepsy in the genomic era. J Neurogenet 2018; 32:295-312. [PMID: 30247086 DOI: 10.1080/01677063.2018.1513509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The technological advancement of next-generation sequencing has greatly accelerated the pace of variant discovery in epilepsy. Despite an initial focus on autosomal dominant epilepsy due to the tractable nature of variant discovery with trios under a de novo model, more and more variants are being reported in families with epilepsies consistent with autosomal recessive (AR) inheritance. In this review, we touch on the classical AR epilepsy variants such as the inborn errors of metabolism and malformations of cortical development. However, we also highlight recently reported genes that are being identified by next-generation sequencing approaches and online 'matchmaking' platforms. Syndromes mainly characterized by seizures and complex neurodevelopmental disorders comorbid with epilepsy are discussed as an example of the wide phenotypic spectrum associated with the AR epilepsies. We conclude with a foray into the future, from the application of whole-genome sequencing to identify elusive epilepsy variants, to the promise of precision medicine initiatives to provide novel targeted therapeutics specific to the individual based on their clinical genetic testing.
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Affiliation(s)
- Jeffrey D Calhoun
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
| | - Gemma L Carvill
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
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86
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Canestrari E, Paroo Z. Ribonucleases as Drug Targets. Trends Pharmacol Sci 2018; 39:855-866. [PMID: 30144949 DOI: 10.1016/j.tips.2018.07.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/26/2022]
Abstract
Across disease indications, there is immediate need for new drug targets. Target scarcity is reflected in a growing number of same-target drugs of marginal clinical value. Advances in RNA mechanisms of disease are revealing a windfall of targets for nucleic acids therapeutics. However, nucleic acids remain limited as pharmaceutical agents. Because enzymes are predominant drug targets, ribonucleases represent an established target class to capitalize on RNA mechanisms of disease. Analysis of the human proteome identified 122 ribonucleases. This small ribonucleome mediates the biosynthetic and catabolic processing of a large transcriptome. Thus, ribonucleases represent critical signaling targets. Similar to kinases, proteases, and epigenetic enzymes, ribonucleases are rational targets for development of therapies with novel mechanisms, expanding treatment options for improved patient outcomes.
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Affiliation(s)
- Emanuele Canestrari
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Zain Paroo
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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87
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Towler BP, Newbury SF. Regulation of cytoplasmic RNA stability: Lessons from Drosophila. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1499. [PMID: 30109918 DOI: 10.1002/wrna.1499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 06/06/2018] [Accepted: 07/01/2018] [Indexed: 12/19/2022]
Abstract
The process of RNA degradation is a critical level of regulation contributing to the control of gene expression. In the last two decades a number of studies have shown the specific and targeted nature of RNA decay and its importance in maintaining homeostasis. The key players within the pathways of RNA decay are well conserved with their mutation or disruption resulting in distinct phenotypes as well as human disease. Model organisms including Drosophila melanogaster have played a substantial role in elucidating the mechanisms conferring control over RNA stability. A particular advantage of this model organism is that the functions of ribonucleases can be assessed in the context of natural cells within tissues in addition to individual immortalized cells in culture. Drosophila RNA stability research has demonstrated how the cytoplasmic decay machines, such as the exosome, Dis3L2 and Xrn1, are responsible for regulating specific processes including apoptosis, proliferation, wound healing and fertility. The work discussed here has begun to identify specific mRNA transcripts that appear sensitive to specific decay pathways representing mechanisms through which the ribonucleases control mRNA stability. Drosophila research has also contributed to our knowledge of how specific RNAs are targeted to the ribonucleases including AU rich elements, miRNA targeting and 3' tailing. Increased understanding of these mechanisms is critical to elucidating the control elicited by the cytoplasmic ribonucleases which is relevant to human disease. This article is categorized under: RNA in Disease and Development > RNA in Development RNA Turnover and Surveillance > Regulation of RNA Stability RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms.
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Affiliation(s)
- Benjamin P Towler
- Brighton and Sussex Medical School, University of Sussex, Brighton, UK
| | - Sarah F Newbury
- Brighton and Sussex Medical School, University of Sussex, Brighton, UK
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88
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Richards RI, Robertson SA, Kastner DL. Neurodegenerative diseases have genetic hallmarks of autoinflammatory disease. Hum Mol Genet 2018; 27:R108-R118. [PMID: 29684205 PMCID: PMC6061832 DOI: 10.1093/hmg/ddy139] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 03/12/2018] [Accepted: 04/16/2018] [Indexed: 12/25/2022] Open
Abstract
The notion that one common pathogenic pathway could account for the various clinically distinguishable, typically late-onset neurodegenerative diseases might appear unlikely given the plethora of diverse primary causes of neurodegeneration. On the contrary, an autoinflammatory pathogenic mechanism allows diverse genetic and environmental factors to converge into a common chain of causality. Inflammation has long been known to correlate with neurodegeneration. Until recently this relationship was seen as one of consequence rather than cause-with inflammatory cells and events acting to 'clean up the mess' after neurological injury. This explanation is demonstrably inadequate and it is now clear that inflammation is at the very least, rate-limiting for neurodegeneration (and more likely, a principal underlying cause in most if not all neurodegenerative diseases), protective in its initial acute phase, but pernicious in its latter chronic phase.
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Affiliation(s)
- Robert I Richards
- Department of Molecular and Biomedical Sciences, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Sarah A Robertson
- Robinson Research Institute, School of Medicine, The University of Adelaide, Adelaide, SA, Australia
| | - Daniel L Kastner
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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89
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Ivanov I, Atkinson D, Litvinenko I, Angelova L, Andonova S, Mumdjiev H, Pacheva I, Panova M, Yordanova R, Belovejdov V, Petrova A, Bosheva M, Shmilev T, Savov A, Jordanova A. Pontocerebellar hypoplasia type 1 for the neuropediatrician: Genotype-phenotype correlations and diagnostic guidelines based on new cases and overview of the literature. Eur J Paediatr Neurol 2018; 22:674-681. [PMID: 29656927 DOI: 10.1016/j.ejpn.2018.03.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/20/2018] [Accepted: 03/27/2018] [Indexed: 10/17/2022]
Abstract
Pontocerebellar hypoplasia type 1 (PCH1) is a major cause of non-5q spinal muscular atrophy (SMA). We screened 128 SMN1-negative SMA patients from Bulgaria for a frequent mutation -p.G31A in EXOSC3, and performed a literature review of all genetically verified PCH1 cases. Homozygous p.G31A/EXOSC3 mutation was identified in 14 Roma patients, representing three fourths of all our SMN1-negative Roma SMA cases. The phenotype of the p.G31A/EXOSC3 homozygotes was compared to the clinical presentation of all reported to date genetically verified PCH1 cases. Signs of antenatal onset of disease present at birth were common in all PCH1 sub-types except in the homozygous p.D132A/EXOSC3 patients. The PCH1sub-types with early death (between ages 1 day and 17 months), seen in patients with p.G31A/EXOSC3 or SLC25A46 mutations have a SMA type 1-like clinical presentation but with global developmental delay, visual and hearing impairment, with or without microcephaly, nystagmus and optic atrophy. Mutations with milder presentation (homozygous p.D132A/EXOSC3 or VRK1) may display additionally signs of upper motor neuron impairment, dystonia or ataxia and die at age between 5 and 18 years. Other EXOSC3 mutations and EXOSC8 cases are intermediate - SMA type 1-like presentation, spasticity (mostly in EXOSC8) and death between 3 months and 5 years. There is no correlation between neurological onset and duration of life. We add marble-like skin and congenital laryngeal stridor as features of PCH1. We show that imaging signs of cerebellar and pontine hypoplasia may be missing early in infancy. EMG signs of anterior horn neuronopathy may be missing in PCH1 patients with SLC25A46 mutations. Thus, there is considerable phenotypic variability in PCH1, with some cases being more SMA-like, than PCH-like. Detailed clinical evaluation and ethnicity background may guide genetic testing and subsequent genetic counseling.
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Affiliation(s)
- I Ivanov
- Department of Pediatrics, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - D Atkinson
- VIB Center for Molecular Neurology, University of Antwerp, Belgium.
| | - I Litvinenko
- Department of Pediatrics, SBALDB "Prof. D-r Ivan Mitev", Medical University-Sofia, Sofia, Bulgaria.
| | - L Angelova
- Department of Medical Genetics, University Hospital "St. Marina", Medical University of Varna, Varna, Bulgaria.
| | - S Andonova
- National Genetic Laboratory, Maichin Dom University Hospital, Sofia, Bulgaria.
| | - H Mumdjiev
- Department of Neonatology, Prof. Stoyan Kirkovich University Hospital, Medical Faculty of Tracian University, Stara Zagora, Bulgaria.
| | - I Pacheva
- Department of Pediatrics, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - M Panova
- Department of Pediatrics, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - R Yordanova
- Department of Pediatrics, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - V Belovejdov
- Department of Pathology, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - A Petrova
- Department of Radiology, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - M Bosheva
- Department of Pediatrics, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - T Shmilev
- Department of Pediatrics, St. George University Hospital, Medical University-Plovdiv, Plovdiv, Bulgaria.
| | - A Savov
- National Genetic Laboratory, Maichin Dom University Hospital, Sofia, Bulgaria.
| | - A Jordanova
- VIB Center for Molecular Neurology, University of Antwerp, Belgium; Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Sofia, Bulgaria.
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90
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van Dijk T, Baas F, Barth PG, Poll-The BT. What's new in pontocerebellar hypoplasia? An update on genes and subtypes. Orphanet J Rare Dis 2018; 13:92. [PMID: 29903031 PMCID: PMC6003036 DOI: 10.1186/s13023-018-0826-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 05/16/2018] [Indexed: 12/25/2022] Open
Abstract
Background Pontocerebellar hypoplasia (PCH) describes a rare, heterogeneous group of neurodegenerative disorders mainly with a prenatal onset. Patients have severe hypoplasia or atrophy of cerebellum and pons, with variable involvement of supratentorial structures, motor and cognitive impairments. Based on distinct clinical features and genetic causes, current classification comprises 11 types of PCH. Main text In this review we describe the clinical, neuroradiological and genetic characteristics of the different PCH subtypes, summarize the differential diagnosis and reflect on potential disease mechanisms in PCH. Seventeen PCH-related genes are now listed in the OMIM database, most of them have a function in RNA processing or translation. It is unknown why defects in these apparently ubiquitous processes result in a brain-specific phenotype. Conclusions Many new PCH related genes and phenotypes have been described due to the appliance of next generation sequencing techniques. By including such a broad range of phenotypes, including non-degenerative and postnatal onset disorders, the current classification gives rise to confusion. Despite the discovery of new pathways involved in PCH, treatment is still symptomatic. However, correct diagnosis of PCH is important to provide suitable care and counseling regarding prognosis, and offer appropriate (prenatal) genetic testing to families.
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Affiliation(s)
- Tessa van Dijk
- Department of Clinical Genetics, Academic Medical Center, Amsterdam, The Netherlands.,Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Frank Baas
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Peter G Barth
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands
| | - Bwee Tien Poll-The
- Department of Pediatric Neurology, Academic Medical Center, Amsterdam, The Netherlands.
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91
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Corbett AH. Post-transcriptional regulation of gene expression and human disease. Curr Opin Cell Biol 2018; 52:96-104. [PMID: 29518673 PMCID: PMC5988930 DOI: 10.1016/j.ceb.2018.02.011] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 02/08/2018] [Accepted: 02/15/2018] [Indexed: 12/18/2022]
Abstract
A large number of mutations in genes that encode RNA binding proteins cause human disease. Many of these RNA binding proteins mediate key steps in post-transcriptional regulation of gene expression from mRNA processing to eventual decay in the cytoplasm. Surprisingly, these RNA binding proteins, which are ubiquitously expressed and play fundamental roles in gene expression, are often altered in tissue-specific disease. Mutations linked to disease impact nearly every post-transcriptional processing step and cause diverse disease phenotypes in a variety of specific tissues. This review summarizes steps in post-transcriptional regulation of gene expression that have been linked to disease providing specific examples of some of the many genes affected. Finally, recent advances that hold promise for treatment of some of these diseases are presented.
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Affiliation(s)
- Anita H Corbett
- Department of Biology, RRC 1021, Emory University, 1510 Clifton Road, NE, Atlanta 30322, GA, United States.
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92
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Zebrafish Models of Rare Hereditary Pediatric Diseases. Diseases 2018; 6:diseases6020043. [PMID: 29789451 PMCID: PMC6023479 DOI: 10.3390/diseases6020043] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/17/2018] [Accepted: 05/19/2018] [Indexed: 12/12/2022] Open
Abstract
Recent advances in sequencing technologies have made it significantly easier to find the genetic roots of rare hereditary pediatric diseases. These novel methods are not panaceas, however, and they often give ambiguous results, highlighting multiple possible causative mutations in affected patients. Furthermore, even when the mapping results are unambiguous, the affected gene might be of unknown function. In these cases, understanding how a particular genotype can result in a phenotype also needs carefully designed experimental work. Model organism genetics can offer a straightforward experimental setup for hypothesis testing. Containing orthologs for over 80% of the genes involved in human diseases, zebrafish (Danio rerio) has emerged as one of the top disease models over the past decade. A plethora of genetic tools makes it easy to create mutations in almost any gene of the zebrafish genome and these mutant strains can be used in high-throughput preclinical screens for active molecules. As this small vertebrate species offers several other advantages as well, its popularity in biomedical research is bound to increase, with “aquarium to bedside” drug development pipelines taking a more prevalent role in the near future.
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93
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Mpp6 Incorporation in the Nuclear Exosome Contributes to RNA Channeling through the Mtr4 Helicase. Cell Rep 2018; 20:2279-2286. [PMID: 28877463 PMCID: PMC5603729 DOI: 10.1016/j.celrep.2017.08.033] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/27/2017] [Accepted: 08/11/2017] [Indexed: 12/24/2022] Open
Abstract
The RNA-degrading exosome mediates the processing and decay of many cellular transcripts. In the yeast nucleus, the ubiquitous 10-subunit exosome core complex (Exo-9–Rrp44) functions with four conserved cofactors (Rrp6, Rrp47, Mtr4, and Mpp6). Biochemical and structural studies to date have shed insights into the mechanisms of the exosome core and its nuclear cofactors, with the exception of Mpp6. We report the 3.2-Å resolution crystal structure of a S. cerevisiae Exo-9–Mpp6 complex, revealing how linear motifs in the Mpp6 middle domain bind Rrp40 via evolutionary conserved residues. In particular, Mpp6 binds near a tryptophan residue of Rrp40 that is mutated in human patients suffering from pontocerebellar hypoplasia. Using biochemical assays, we show that Mpp6 is required for the ability of Mtr4 to extend the trajectory of an RNA entering the exosome core, suggesting that it promotes the channeling of substrates from the nuclear helicase to the processive RNase. Yeast Mpp6 is stably bound to the nuclear exosome core both in vivo and in vitro The Mpp6 middle domain binds the Rrp40 exosome subunit with conserved interactions Mpp6 enhances the ability of the Mtr4 helicase to channel RNA into the exosome core The pontocerebellar W238R mutation in human EXOSC3 affects the hMPP6-binding site
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94
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Rossi M, Anheim M, Durr A, Klein C, Koenig M, Synofzik M, Marras C, van de Warrenburg BP. The genetic nomenclature of recessive cerebellar ataxias. Mov Disord 2018; 33:1056-1076. [PMID: 29756227 DOI: 10.1002/mds.27415] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/15/2018] [Accepted: 03/25/2018] [Indexed: 12/17/2022] Open
Abstract
The recessive cerebellar ataxias are a large group of degenerative and metabolic disorders, the diagnostic management of which is difficult because of the enormous clinical and genetic heterogeneity. Because of several limitations, the current classification systems provide insufficient guidance for clinicians and researchers. Here, we propose a new nomenclature for the genetically confirmed recessive cerebellar ataxias according to the principles and criteria laid down by the International Parkinson and Movement Disorder Society Task Force on Classification and Nomenclature of Genetic Movement Disorders. We apply stringent criteria for considering an association between gene and phenotype to be established. The newly proposed list of recessively inherited cerebellar ataxias includes 62 disorders that were assigned an ATX prefix, followed by the gene name, because these typically present with ataxia as a predominant and/or consistent feature. An additional 30 disorders that often combine ataxia with a predominant or consistent other movement disorder received a double prefix (e.g., ATX/HSP). We also identified a group of 89 entities that usually present with complex nonataxia phenotypes, but may occasionally present with cerebellar ataxia. These are listed separately without the ATX prefix. This new, transparent and adaptable nomenclature of the recessive cerebellar ataxias will facilitate the clinical recognition of recessive ataxias, guide diagnostic testing in ataxia patients, and help in interpreting genetic findings. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Malco Rossi
- Movement Disorders Section, Neuroscience Department, Raul Carrea Institute for Neurological Research, Buenos Aires, Argentina
| | - Mathieu Anheim
- Département de Neurologie, Hôpitaux Universitaires de Strasbourg, Hôpital de Hautepierre, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch, France.,Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Alexandra Durr
- Brain and Spine Institute, Sorbonne Université, Inserm U1127, CNRS UMR 7225, Pitié-Salpêtrière University Hospital, Paris, France.,Department of Genetics, AP-HP, Pitié-Salpêtrière University Hospital, 7501, Paris, France
| | - Christine Klein
- Institute of Neurogenetics, University of Luebeck, Luebeck, Germany.,Department of Neurology, University Hospital Schleswig-Holstein, Campus Lübeck, Germany
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares, EA7402, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU Montpellier, Montpellier, France
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases, Tübingen, Germany
| | - Connie Marras
- Toronto Western Hospital Morton, Gloria Shulman Movement Disorders Centre, and the Edmond J. Safra Program in Parkinson's Disease, University of Toronto, Toronto, Canada
| | - Bart P van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition & Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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95
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Singh P, Saha U, Paira S, Das B. Nuclear mRNA Surveillance Mechanisms: Function and Links to Human Disease. J Mol Biol 2018; 430:1993-2013. [PMID: 29758258 DOI: 10.1016/j.jmb.2018.05.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/30/2018] [Accepted: 05/07/2018] [Indexed: 01/05/2023]
Abstract
Production of export-competent mRNAs involves transcription and a series of dynamic processing and modification events of pre-messenger RNAs in the nucleus. Mutations in the genes encoding the transcription and mRNP processing machinery and the complexities involved in the biogenesis events lead to the formation of aberrant messages. These faulty transcripts are promptly eliminated by the nuclear RNA exosome and its cofactors to safeguard the cells and organisms from genetic catastrophe. Mutations in the components of the core nuclear exosome and its cofactors lead to the tissue-specific dysfunction of exosomal activities, which are linked to diverse human diseases and disorders. In this article, we examine the structure and function of both the yeast and human RNA exosome complex and its cofactors, discuss the nature of the various altered amino acid residues implicated in these diseases with the speculative mechanisms of the mutation-induced disorders and project the frontier and prospective avenues of the future research in this field.
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Affiliation(s)
- Pragyan Singh
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Upasana Saha
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Sunirmal Paira
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India.
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96
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97
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Burns DT, Donkervoort S, Müller JS, Knierim E, Bharucha-Goebel D, Faqeih EA, Bell SK, AlFaifi AY, Monies D, Millan F, Retterer K, Dyack S, MacKay S, Morales-Gonzalez S, Giunta M, Munro B, Hudson G, Scavina M, Baker L, Massini TC, Lek M, Hu Y, Ezzo D, AlKuraya FS, Kang PB, Griffin H, Foley AR, Schuelke M, Horvath R, Bönnemann CG. Variants in EXOSC9 Disrupt the RNA Exosome and Result in Cerebellar Atrophy with Spinal Motor Neuronopathy. Am J Hum Genet 2018; 102:858-873. [PMID: 29727687 PMCID: PMC5986733 DOI: 10.1016/j.ajhg.2018.03.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/06/2018] [Indexed: 12/30/2022] Open
Abstract
The exosome is a conserved multi-protein complex that is essential for correct RNA processing. Recessive variants in exosome components EXOSC3, EXOSC8, and RBM7 cause various constellations of pontocerebellar hypoplasia (PCH), spinal muscular atrophy (SMA), and central nervous system demyelination. Here, we report on four unrelated affected individuals with recessive variants in EXOSC9 and the effect of the variants on the function of the RNA exosome in vitro in affected individuals' fibroblasts and skeletal muscle and in vivo in zebrafish. The clinical presentation was severe, early-onset, progressive SMA-like motor neuronopathy, cerebellar atrophy, and in one affected individual, congenital fractures of the long bones. Three affected individuals of different ethnicity carried the homozygous c.41T>C (p.Leu14Pro) variant, whereas one affected individual was compound heterozygous for c.41T>C (p.Leu14Pro) and c.481C>T (p.Arg161∗). We detected reduced EXOSC9 in fibroblasts and skeletal muscle and observed a reduction of the whole multi-subunit exosome complex on blue-native polyacrylamide gel electrophoresis. RNA sequencing of fibroblasts and skeletal muscle detected significant >2-fold changes in genes involved in neuronal development and cerebellar and motor neuron degeneration, demonstrating the widespread effect of the variants. Morpholino oligonucleotide knockdown and CRISPR/Cas9-mediated mutagenesis of exosc9 in zebrafish recapitulated aspects of the human phenotype, as they have in other zebrafish models of exosomal disease. Specifically, portions of the cerebellum and hindbrain were absent, and motor neurons failed to develop and migrate properly. In summary, we show that variants in EXOSC9 result in a neurological syndrome combining cerebellar atrophy and spinal motoneuronopathy, thus expanding the list of human exosomopathies.
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98
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Bourgeois P, Esteve C, Chaix C, Béroud C, Lévy N, Fabre A, Badens C. Tricho-Hepato-Enteric Syndrome mutation update: Mutations spectrum of TTC37 and SKIV2L, clinical analysis and future prospects. Hum Mutat 2018. [PMID: 29527791 DOI: 10.1002/humu.23418] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tricho-Hepato-Enteric syndrome (THES) is a very rare autosomal recessive syndromic enteropathy caused by mutations of either TTC37 or SKIV2L genes. Very little is known of these two gene products in mammals nor of the pathophysiology of the disease. Since the identification of the genes, we have set up the molecular diagnostic of THES in routine, gathering a large cohort with clinical and molecular data. Here, we report the phenotype and genotype analysis of this cohort together with an extensive literature review of THES cases worldwide, that is, 96 individuals harboring mutations in one gene or the other. We set up locus-specific databases for both genes and reviewed the type of mutation as well as their localization in the proteins. No hot spot is evidenced for any type of mutation. The phenotypic analysis was first made on the whole cohort but is limited due to heterogeneity in clinical descriptions. We then examined the lab diagnostic cohort in detail for clinical manifestations. For the first time, we are able to suggest that patients lacking SKIV2L seem more severely affected than those lacking TTC37, in terms of liver damage and prenatal growth impairment.
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Affiliation(s)
- Patrice Bourgeois
- Molecular genetics Laboratory, Medical genetics and Cell biology Department, La Timone children's hospital, Assistance-Publique des Hôpitaux de Marseille (APHM), Marseille, France.,GMGF, Aix Marseille Univ, Marseille, France
| | | | - Charlène Chaix
- Molecular genetics Laboratory, Medical genetics and Cell biology Department, La Timone children's hospital, Assistance-Publique des Hôpitaux de Marseille (APHM), Marseille, France
| | - Christophe Béroud
- Molecular genetics Laboratory, Medical genetics and Cell biology Department, La Timone children's hospital, Assistance-Publique des Hôpitaux de Marseille (APHM), Marseille, France.,GMGF, Aix Marseille Univ, Marseille, France
| | - Nicolas Lévy
- Molecular genetics Laboratory, Medical genetics and Cell biology Department, La Timone children's hospital, Assistance-Publique des Hôpitaux de Marseille (APHM), Marseille, France.,GMGF, Aix Marseille Univ, Marseille, France
| | | | - Alexandre Fabre
- GMGF, Aix Marseille Univ, Marseille, France.,Multidisciplinary Pediatric Service - La Timone Children's Hospital, Assistance-Publique des Hôpitaux de Marseille (APHM), Marseille, France
| | - Catherine Badens
- Molecular genetics Laboratory, Medical genetics and Cell biology Department, La Timone children's hospital, Assistance-Publique des Hôpitaux de Marseille (APHM), Marseille, France.,GMGF, Aix Marseille Univ, Marseille, France
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99
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Clinical and genetic spectrum of AMPD2-related pontocerebellar hypoplasia type 9. Eur J Hum Genet 2018; 26:695-708. [PMID: 29463858 DOI: 10.1038/s41431-018-0098-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/28/2017] [Accepted: 01/09/2018] [Indexed: 11/08/2022] Open
Abstract
Pontocerebellar hypoplasia (PCH) represents a group of autosomal-recessive progressive neurodegenerative disorders of prenatal onset. Eleven PCH subtypes are classified according to clinical, neuroimaging and genetic findings. Individuals with PCH type 9 (PCH9) have a unique combination of postnatal microcephaly, hypoplastic cerebellum and pons, and hypoplastic or absent corpus callosum. PCH9 is caused by biallelic variants in AMPD2 encoding adenosine monophosphate deaminase 2; however, a homozygous AMPD2 frameshift variant has recently been reported in two family members with spastic paraplegia type 63 (SPG63). We identified homozygous or compound heterozygous AMPD2 variants in eight PCH-affected individuals from six families. The eight variants likely affect function and comprise one frameshift, one nonsense and six missense variants; seven of which were novel. The main clinical manifestations in the eight new patients and 17 previously reported individuals with biallelic AMPD2 variants were postnatal microcephaly, severe global developmental delay, spasticity, and central visual impairment. Brain imaging data identified hypomyelination, hypoplasia of the cerebellum and pons, atrophy of the cerebral cortex, complete or partial agenesis of the corpus callosum and the "figure 8" shape of the hypoplastic midbrain as consistent features. We broaden the AMPD2-related clinical spectrum by describing one individual without microcephaly and absence of the characteristic "figure 8" shape of the midbrain. The existence of various AMPD2 isoforms with different functions possibly explains the variability in phenotypes associated with AMPD2 variants: variants leaving some of the isoforms intact may cause SPG63, while those affecting all isoforms may result in the severe and early-onset PCH9.
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100
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Han J, van Hoof A. The RNA Exosome Channeling and Direct Access Conformations Have Distinct In Vivo Functions. Cell Rep 2018; 16:3348-3358. [PMID: 27653695 DOI: 10.1016/j.celrep.2016.08.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 06/06/2016] [Accepted: 08/18/2016] [Indexed: 10/21/2022] Open
Abstract
The RNA exosome is a 3'-5' ribonuclease complex that is composed of nine core subunits and an essential catalytic subunit, Rrp44. Two distinct conformations of Rrp44 were revealed in previous structural studies, suggesting that Rrp44 may change its conformation to exert its function. In the channeling conformation, (Rrp44(ch)), RNA accesses the active site after traversing the central channel of the RNA exosome, whereas in the other conformation, (Rrp44(da)), RNA gains direct access to the active site. Here, we show that the Rrp44(da) exosome is important for nuclear function of the RNA exosome. Defects caused by disrupting the direct access conformation are distinct from those caused by channel-occluding mutations, indicating specific functions for each conformation. Our genetic analyses provide in vivo evidence that the RNA exosome employs a direct-access route to recruit specific substrates, indicating that the RNA exosome uses alternative conformations to act on different RNA substrates.
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Affiliation(s)
- Jaeil Han
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 1.212, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 1.212, Houston, TX 77030, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 1.212, Houston, TX 77030, USA; The University of Texas Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, 6431 Fannin Street, MSB 1.212, Houston, TX 77030, USA.
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