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Costa RG, Conceição A, Matos CA, Nóbrega C. The polyglutamine protein ATXN2: from its molecular functions to its involvement in disease. Cell Death Dis 2024; 15:415. [PMID: 38877004 PMCID: PMC11178924 DOI: 10.1038/s41419-024-06812-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/16/2024]
Abstract
A CAG repeat sequence in the ATXN2 gene encodes a polyglutamine (polyQ) tract within the ataxin-2 (ATXN2) protein, showcasing a complex landscape of functions that have been progressively unveiled over recent decades. Despite significant progresses in the field, a comprehensive overview of the mechanisms governed by ATXN2 remains elusive. This multifaceted protein emerges as a key player in RNA metabolism, stress granules dynamics, endocytosis, calcium signaling, and the regulation of the circadian rhythm. The CAG overexpansion within the ATXN2 gene produces a protein with an extended poly(Q) tract, inducing consequential alterations in conformational dynamics which confer a toxic gain and/or partial loss of function. Although overexpanded ATXN2 is predominantly linked to spinocerebellar ataxia type 2 (SCA2), intermediate expansions are also implicated in amyotrophic lateral sclerosis (ALS) and parkinsonism. While the molecular intricacies await full elucidation, SCA2 presents ATXN2-associated pathological features, encompassing autophagy impairment, RNA-mediated toxicity, heightened oxidative stress, and disruption of calcium homeostasis. Presently, SCA2 remains incurable, with patients reliant on symptomatic and supportive treatments. In the pursuit of therapeutic solutions, various studies have explored avenues ranging from pharmacological drugs to advanced therapies, including cell or gene-based approaches. These endeavours aim to address the root causes or counteract distinct pathological features of SCA2. This review is intended to provide an updated compendium of ATXN2 functions, delineate the associated pathological mechanisms, and present current perspectives on the development of innovative therapeutic strategies.
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Affiliation(s)
- Rafael G Costa
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- PhD program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
| | - André Conceição
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), Coimbra, Portugal
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Carlos A Matos
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
| | - Clévio Nóbrega
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
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2
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Li L, Yu S, Dou N, Wang X, Gao Y, Li Y. A new tandem repeat-enriched lncRNA XLOC_008672 promotes gastric carcinogenesis by regulating G3BP1 expression. Cancer Sci 2024; 115:1851-1865. [PMID: 38581120 PMCID: PMC11145122 DOI: 10.1111/cas.16172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 03/11/2024] [Accepted: 03/23/2024] [Indexed: 04/08/2024] Open
Abstract
Aberrant expression of forkhead box transcription factor 1 (FOXM1) plays critical roles in a variety of human malignancies and predicts poor prognosis. However, little is known about the crosstalk between FOXM1 and long noncoding RNAs (lncRNAs) in tumorigenesis. The present study identifies a previously uncharacterized lncRNA XLOC_008672 in gastric cancer (GC), which is regulated by FOXM1 and possesses multiple copies of tandem repetitive sequences. LncRNA microarrays are used to screen differentially expressed lncRNAs in FOXM1 knockdown GC cells, and then the highest fold downregulation lncRNA XLOC_008672 is screened out. Sequence analysis reveals that the new lncRNA contains 62 copies of 37-bp tandem repeats. It is transcriptionally activated by FOXM1 and functions as a downstream effector of FOXM1 in GC cells through in vitro and in vivo functional assays. Elevated expression of XLOC_008672 is found in GC tissues and indicates worse prognosis. Mechanistically, XLOC_008672 can bind to small nuclear ribonucleoprotein polypeptide A (SNRPA), thereby enhancing mRNA stability of Ras-GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) and, consequently, facilitating GC cell proliferation and migration. Our study discovers a new uncharacterized lncRNA XLOC_008672 involved in GC carcinogenesis and progression. Targeting FOXM1/XLOC_008672/SNRPA/G3BP1 signaling axis might be a promising therapeutic strategy for GC.
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Affiliation(s)
- Li Li
- Department of Oncology, Shanghai East HospitalTongji University School of MedicineShanghaiChina
| | - Shijun Yu
- Department of Oncology, Shanghai East HospitalTongji University School of MedicineShanghaiChina
| | - Ning Dou
- Department of Oncology, Shanghai East HospitalTongji University School of MedicineShanghaiChina
| | - Xiao Wang
- Department of Medical Oncology, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Yong Gao
- Department of Oncology, Shanghai East HospitalTongji University School of MedicineShanghaiChina
| | - Yandong Li
- Department of Oncology, Shanghai East HospitalTongji University School of MedicineShanghaiChina
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3
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Degener MJF, van Cruchten RTP, Otero BA, Wang E, Wansink DG, ‘t Hoen PAC. A comprehensive atlas of fetal splicing patterns in the brain of adult myotonic dystrophy type 1 patients. NAR Genom Bioinform 2022; 4:lqac016. [PMID: 35274098 PMCID: PMC8903011 DOI: 10.1093/nargab/lqac016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 01/28/2022] [Accepted: 02/13/2022] [Indexed: 11/14/2022] Open
Abstract
In patients with myotonic dystrophy type 1 (DM1), dysregulation of RNA-binding proteins like MBNL and CELF1 leads to alternative splicing of exons and is thought to induce a return to fetal splicing patterns in adult tissues, including the central nervous system (CNS). To comprehensively evaluate this, we created an atlas of developmentally regulated splicing patterns in the frontal cortex of healthy individuals and DM1 patients, by combining RNA-seq data from BrainSpan, GTEx and DM1 patients. Thirty-four splice events displayed an inclusion pattern in DM1 patients that is typical for the fetal situation in healthy individuals. The regulation of DM1-relevant splicing patterns could partly be explained by changes in mRNA expression of the splice regulators MBNL1, MBNL2 and CELF1. On the contrary, interindividual differences in splicing patterns between healthy adults could not be explained by differential expression of these splice regulators. Our findings lend transcriptome-wide evidence to the previously noted shift to fetal splicing patterns in the adult DM1 brain as a consequence of an imbalance in antagonistic MBNL and CELF1 activities. Our atlas serves as a solid foundation for further study and understanding of the cognitive phenotype in patients.
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Affiliation(s)
- Max J F Degener
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Remco T P van Cruchten
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Brittney A Otero
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, FL 32610-0266 Gainesville, FL, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, Genetics Institute, University of Florida, FL 32610-0266 Gainesville, FL, USA
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Peter A C ‘t Hoen
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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4
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Disrupting the Molecular Pathway in Myotonic Dystrophy. Int J Mol Sci 2021; 22:ijms222413225. [PMID: 34948025 PMCID: PMC8708683 DOI: 10.3390/ijms222413225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 01/26/2023] Open
Abstract
Myotonic dystrophy is the most common muscular dystrophy in adults. It consists of two forms: type 1 (DM1) and type 2 (DM2). DM1 is associated with a trinucleotide repeat expansion mutation, which is transcribed but not translated into protein. The mutant RNA remains in the nucleus, which leads to a series of downstream abnormalities. DM1 is widely considered to be an RNA-based disorder. Thus, we consider three areas of the RNA pathway that may offer targeting opportunities to disrupt the production, stability, and degradation of the mutant RNA.
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Yap K, Chung TH, Makeyev EV. Hybridization-proximity labeling reveals spatially ordered interactions of nuclear RNA compartments. Mol Cell 2021; 82:463-478.e11. [PMID: 34741808 PMCID: PMC8791277 DOI: 10.1016/j.molcel.2021.10.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/11/2022]
Abstract
The ability of RNAs to form specific contacts with other macromolecules provides an important mechanism for subcellular compartmentalization. Here we describe a suite of hybridization-proximity (HyPro) labeling technologies for unbiased discovery of proteins (HyPro-MS) and transcripts (HyPro-seq) associated with RNAs of interest in genetically unperturbed cells. As a proof of principle, we show that HyPro-MS and HyPro-seq can identify both known and previously unexplored spatial neighbors of the noncoding RNAs 45S, NEAT1, and PNCTR expressed at markedly different levels. Notably, HyPro-seq uncovers an extensive repertoire of incompletely processed, adenosine-to-inosine-edited transcripts accumulating at the interface between their encoding chromosomal regions and the NEAT1-containing paraspeckle compartment. At least some of these targets require NEAT1 for their optimal expression. Overall, this study provides a versatile toolkit for dissecting RNA interactomes in diverse biomedical contexts and expands our understanding of the functional architecture of the mammalian nucleus. HyPro labeling uncovers interactors and spatial neighbors of RNAs of interest Protein and RNA partners are identified by mass spectrometry and deep sequencing No genetic modifications are required, allowing wider biomedical use Interactomes of RNA-containing nuclear bodies are mapped as a proof of principle
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Affiliation(s)
- Karen Yap
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Tek Hong Chung
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK.
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6
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Li PP, Moulick R, Feng H, Sun X, Arbez N, Jin J, Marque LO, Hedglen E, Chan HE, Ross CA, Pulst SM, Margolis RL, Woodson S, Rudnicki DD. RNA Toxicity and Perturbation of rRNA Processing in Spinocerebellar Ataxia Type 2. Mov Disord 2021; 36:2519-2529. [PMID: 34390268 PMCID: PMC8884117 DOI: 10.1002/mds.28729] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/03/2021] [Accepted: 07/12/2021] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease caused by expansion of a CAG repeat in Ataxin-2 (ATXN2) gene. The mutant ATXN2 protein with a polyglutamine tract is known to be toxic and contributes to the SCA2 pathogenesis. OBJECTIVE Here, we tested the hypothesis that the mutant ATXN2 transcript with an expanded CAG repeat (expATXN2) is also toxic and contributes to SCA2 pathogenesis. METHODS The toxic effect of expATXN2 transcripts on SK-N-MC neuroblastoma cells and primary mouse cortical neurons was evaluated by caspase 3/7 activity and nuclear condensation assay, respectively. RNA immunoprecipitation assay was performed to identify RNA binding proteins (RBPs) that bind to expATXN2 RNA. Quantitative PCR was used to examine if ribosomal RNA (rRNA) processing is disrupted in SCA2 and Huntington's disease (HD) human brain tissue. RESULTS expATXN2 RNA induces neuronal cell death, and aberrantly interacts with RBPs involved in RNA metabolism. One of the RBPs, transducin β-like protein 3 (TBL3), involved in rRNA processing, binds to both expATXN2 and expanded huntingtin (expHTT) RNA in vitro. rRNA processing is disrupted in both SCA2 and HD human brain tissue. CONCLUSION These findings provide the first evidence of a contributory role of expATXN2 transcripts in SCA2 pathogenesis, and further support the role of expHTT transcripts in HD pathogenesis. The disruption of rRNA processing, mediated by aberrant interaction of RBPs with expATXN2 and expHTT transcripts, suggest a point of convergence in the pathogeneses of repeat expansion diseases with potential therapeutic implications. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Pan P. Li
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Roumita Moulick
- T.C. Jenkins Department of BiophysicsJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Hongxuan Feng
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Xin Sun
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Nicolas Arbez
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Jing Jin
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Leonard O. Marque
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Erin Hedglen
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - H.Y. Edwin Chan
- Biochemistry Program, School of Life SciencesThe Chinese University of Hong KongHong KongChina
| | - Christopher A. Ross
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- Department of NeuroscienceJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Stefan M. Pulst
- Department of NeurologyUniversity of UtahSalt Lake CityUtahUSA
| | - Russell L. Margolis
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
- Department of NeurologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
| | - Sarah Woodson
- T.C. Jenkins Department of BiophysicsJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Dobrila D. Rudnicki
- Department of Psychiatry and Behavioral Sciences, Division of NeurobiologyJohns Hopkins University School of MedicineBaltimoreMarylandUSA
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7
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Enukashvily NI, Dobrynin MA, Chubar AV. RNA-seeded membraneless bodies: Role of tandemly repeated RNA. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 126:151-193. [PMID: 34090614 DOI: 10.1016/bs.apcsb.2020.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
Abstract
Membraneless organelles (bodies, granules, etc.) are spatially distinct sub-nuclear and cytoplasmic foci involved in all the processes in a living cell, such as development, cell death, carcinogenesis, proliferation, and differentiation. Today the list of the membraneless organelles includes a wide spectrum of intranuclear and cytoplasmic bodies. Proteins with intrinsically disordered regions are the key players in the membraneless body assembly. However, recent data assume an important role of RNA molecules in the process of the liquid-liquid phase separation. High-level expression of RNA above a critical concentration threshold is mandatory to nucleate interactions with specific proteins and for seeding membraneless organelles. RNA components are considered by many authors as the principal determinants of organelle identity. Tandemly repeated (TR) DNA of big satellites (a TR family that includes centromeric and pericentromeric DNA sequences) was believed to be transcriptionally silent for a long period. Now we know about the TR transcription upregulation during gameto- and embryogenesis, carcinogenesis, stress response. In the review, we summarize the recent data about the involvement of TR RNA in the formation of nuclear membraneless granules, bodies, etc., with different functions being in some cases an initiator of the structures assembly. These RNP structures sequestrate and inactivate different proteins and transcripts. The TR induced sequestration is one of the key principles of nuclear architecture and genome functioning. Studying the role of the TR-based membraneless organelles in stress and disease will bring some new ideas for translational medicine.
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Affiliation(s)
- Natella I Enukashvily
- Institute of Cytology RAS, St. Petersburg, Russia; North-Western Medical State University named after I.I. Mechnikov, St. Petersburg, Russia.
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8
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Nutter CA, Bubenik JL, Oliveira R, Ivankovic F, Sznajder ŁJ, Kidd BM, Pinto BS, Otero BA, Carter HA, Vitriol EA, Wang ET, Swanson MS. Cell-type-specific dysregulation of RNA alternative splicing in short tandem repeat mouse knockin models of myotonic dystrophy. Genes Dev 2019; 33:1635-1640. [PMID: 31624084 PMCID: PMC6942047 DOI: 10.1101/gad.328963.119] [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: 05/17/2019] [Accepted: 09/24/2019] [Indexed: 11/25/2022]
Abstract
Short tandem repeats (STRs) are prone to expansion mutations that cause multiple hereditary neurological and neuromuscular diseases. To study pathomechanisms using mouse models that recapitulate the tissue specificity and developmental timing of an STR expansion gene, we used rolling circle amplification and CRISPR/Cas9-mediated genome editing to generate Dmpk CTG expansion (CTGexp) knockin models of myotonic dystrophy type 1 (DM1). We demonstrate that skeletal muscle myoblasts and brain choroid plexus epithelial cells are particularly susceptible to Dmpk CTGexp mutations and RNA missplicing. Our results implicate dysregulation of muscle regeneration and cerebrospinal fluid homeostasis as early pathogenic events in DM1.
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Affiliation(s)
- Curtis A Nutter
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Jodi L Bubenik
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Ruan Oliveira
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Franjo Ivankovic
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Benjamin M Kidd
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Belinda S Pinto
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Brittney A Otero
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Helmut A Carter
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610, USA
| | - Eric T Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, Gainesville, Florida 32610, USA
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Sznajder ŁJ, Swanson MS. Short Tandem Repeat Expansions and RNA-Mediated Pathogenesis in Myotonic Dystrophy. Int J Mol Sci 2019; 20:ijms20133365. [PMID: 31323950 PMCID: PMC6651174 DOI: 10.3390/ijms20133365] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 06/27/2019] [Accepted: 07/08/2019] [Indexed: 12/23/2022] Open
Abstract
Short tandem repeat (STR) or microsatellite, expansions underlie more than 50 hereditary neurological, neuromuscular and other diseases, including myotonic dystrophy types 1 (DM1) and 2 (DM2). Current disease models for DM1 and DM2 propose a common pathomechanism, whereby the transcription of mutant DMPK (DM1) and CNBP (DM2) genes results in the synthesis of CUG and CCUG repeat expansion (CUGexp, CCUGexp) RNAs, respectively. These CUGexp and CCUGexp RNAs are toxic since they promote the assembly of ribonucleoprotein (RNP) complexes or RNA foci, leading to sequestration of Muscleblind-like (MBNL) proteins in the nucleus and global dysregulation of the processing, localization and stability of MBNL target RNAs. STR expansion RNAs also form phase-separated gel-like droplets both in vitro and in transiently transfected cells, implicating RNA-RNA multivalent interactions as drivers of RNA foci formation. Importantly, the nucleation and growth of these nuclear foci and transcript misprocessing are reversible processes and thus amenable to therapeutic intervention. In this review, we provide an overview of potential DM1 and DM2 pathomechanisms, followed by a discussion of MBNL functions in RNA processing and how multivalent interactions between expanded STR RNAs and RNA-binding proteins (RBPs) promote RNA foci assembly.
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Affiliation(s)
- Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
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10
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Darling AL, Breydo L, Rivas EG, Gebru NT, Zheng D, Baker JD, Blair LJ, Dickey CA, Koren J, Uversky VN. Repeated repeat problems: Combinatorial effect of C9orf72-derived dipeptide repeat proteins. Int J Biol Macromol 2019; 127:136-145. [PMID: 30639592 DOI: 10.1016/j.ijbiomac.2019.01.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/16/2018] [Accepted: 01/08/2019] [Indexed: 12/26/2022]
Abstract
A microsatellite expansion mutation in C9orf72 is the most common genetic cause of Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). The expansion mutation leads to C9orf72 loss of function, RNA foci formation, and generation of five species of non-AUG RAN translated dipeptide repeat proteins (DPRs), such as poly(GA), poly(GP), poly(GR), poly(PA), and poly(PR). Although one cell can contain more than type of DPRs, information about interplay between different DPR species is limited. Here we show that the combined expression of distinct C9orf72-derived dipeptide repeat species produces cellular outcomes and structural differences that are unique compared to the expression of a single DPR species, suggesting the complex biological interactions that occur when multiple DPR variants are simultaneously expressed. Our data highlights the need for further analysis of how combined expression of different DPRs affects the disease state.
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Affiliation(s)
- April L Darling
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA.
| | - Leonid Breydo
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - Emma G Rivas
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - Niad T Gebru
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - Dali Zheng
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - Jeremy D Baker
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - Laura J Blair
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - Chad A Dickey
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA
| | - John Koren
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, College of Medicine, Byrd Alzheimer's Institute, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia.
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11
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12
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Abstract
Microsatellite expansions cause more than 40 neurological disorders, including Huntington's disease, myotonic dystrophy, and C9ORF72 amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). These repeat expansion mutations can produce repeat-associated non-ATG (RAN) proteins in all three reading frames, which accumulate in disease-relevant tissues. There has been considerable interest in RAN protein products and their downstream consequences, particularly for the dipeptide proteins found in C9ORF72 ALS/FTD. Understanding how RAN translation occurs, what cellular factors contribute to RAN protein accumulation, and how these proteins contribute to disease should lead to a better understanding of the basic mechanisms of gene expression and human disease.
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Affiliation(s)
- John Douglas Cleary
- From the Center for NeuroGenetics
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
| | - Amrutha Pattamatta
- From the Center for NeuroGenetics
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
| | - Laura P W Ranum
- From the Center for NeuroGenetics,
- Departments of Molecular Genetics and Microbiology and
- Genetics Institute, and
- Neurology, College of Medicine
- McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
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13
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Yap K, Mukhina S, Zhang G, Tan JSC, Ong HS, Makeyev EV. A Short Tandem Repeat-Enriched RNA Assembles a Nuclear Compartment to Control Alternative Splicing and Promote Cell Survival. Mol Cell 2018; 72:525-540.e13. [PMID: 30318443 PMCID: PMC6224606 DOI: 10.1016/j.molcel.2018.08.041] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/31/2018] [Accepted: 08/27/2018] [Indexed: 11/25/2022]
Abstract
Functions of many long noncoding RNAs (lncRNAs) depend on their ability to interact with multiple copies of specific RNA-binding proteins (RBPs). Here, we devised a workflow combining bioinformatics and experimental validation steps to systematically identify RNAs capable of multivalent RBP recruitment. This uncovered a number of previously unknown transcripts encoding high-density RBP recognition arrays within genetically normal short tandem repeats. We show that a top-scoring hit in this screen, lncRNA PNCTR, contains hundreds of pyrimidine tract-binding protein (PTBP1)-specific motifs allowing it to sequester a substantial fraction of PTBP1 in a nuclear body called perinucleolar compartment. Importantly, PNCTR is markedly overexpressed in a variety of cancer cells and its downregulation is sufficient to induce programmed cell death at least in part by stimulating PTBP1 splicing regulation activity. This work expands our understanding of the repeat-containing fraction of the human genome and illuminates a novel mechanism driving malignant transformation of cancer cells. Human genome encodes many transcripts enriched in short tandem repeats (strRNAs) strRNA PNCTR recruits RNA-binding protein PTBP1 to a nuclear body called PNC PNCTR antagonizes splicing regulation function of PTBP1 and promotes cell survival PNCTR is dramatically upregulated in a wide range of cancer cells
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Affiliation(s)
- Karen Yap
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK
| | - Svetlana Mukhina
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Gen Zhang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Jason S C Tan
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Hong Sheng Ong
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London SE1 1UL, UK.
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14
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Thomas JD, Oliveira R, Sznajder ŁJ, Swanson MS. Myotonic Dystrophy and Developmental Regulation of RNA Processing. Compr Physiol 2018; 8:509-553. [PMID: 29687899 PMCID: PMC11323716 DOI: 10.1002/cphy.c170002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Myotonic dystrophy (DM) is a multisystemic disorder caused by microsatellite expansion mutations in two unrelated genes leading to similar, yet distinct, diseases. DM disease presentation is highly variable and distinguished by differences in age-of-onset and symptom severity. In the most severe form, DM presents with congenital onset and profound developmental defects. At the molecular level, DM pathogenesis is characterized by a toxic RNA gain-of-function mechanism that involves the transcription of noncoding microsatellite expansions. These mutant RNAs disrupt key cellular pathways, including RNA processing, localization, and translation. In DM, these toxic RNA effects are predominantly mediated through the modulation of the muscleblind-like and CUGBP and ETR-3-like factor families of RNA binding proteins (RBPs). Dysfunction of these RBPs results in widespread RNA processing defects culminating in the expression of developmentally inappropriate protein isoforms in adult tissues. The tissue that is the focus of this review, skeletal muscle, is particularly sensitive to mutant RNA-responsive perturbations, as patients display a variety of developmental, structural, and functional defects in muscle. Here, we provide a comprehensive overview of DM1 and DM2 clinical presentation and pathology as well as the underlying cellular and molecular defects associated with DM disease onset and progression. Additionally, fundamental aspects of skeletal muscle development altered in DM are highlighted together with ongoing and potential therapeutic avenues to treat this muscular dystrophy. © 2018 American Physiological Society. Compr Physiol 8:509-553, 2018.
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Affiliation(s)
- James D. Thomas
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Ruan Oliveira
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Łukasz J. Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
| | - Maurice S. Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida, USA
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15
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Kirov I, Gilyok M, Knyazev A, Fesenko I. Pilot satellitome analysis of the model plant, Physcomitrellapatens, revealed a transcribed and high-copy IGS related tandem repeat. COMPARATIVE CYTOGENETICS 2018; 12:493-513. [PMID: 30588288 PMCID: PMC6302065 DOI: 10.3897/compcytogen.v12i4.31015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/27/2018] [Indexed: 05/20/2023]
Abstract
Satellite DNA (satDNA) constitutes a substantial part of eukaryotic genomes. In the last decade, it has been shown that satDNA is not an inert part of the genome and its function extends beyond the nuclear membrane. However, the number of model plant species suitable for studying the novel horizons of satDNA functionality is low. Here, we explored the satellitome of the model "basal" plant, Physcomitrellapatens (Hedwig, 1801) Bruch & Schimper, 1849 (moss), which has a number of advantages for deep functional and evolutionary research. Using a newly developed pyTanFinder pipeline (https://github.com/Kirovez/pyTanFinder) coupled with fluorescence in situ hybridization (FISH), we identified five high copy number tandem repeats (TRs) occupying a long DNA array in the moss genome. The nuclear organization study revealed that two TRs had distinct locations in the moss genome, concentrating in the heterochromatin and knob-rDNA like chromatin bodies. Further genomic, epigenetic and transcriptomic analysis showed that one TR, named PpNATR76, was located in the intergenic spacer (IGS) region and transcribed into long non-coding RNAs (lncRNAs). Several specific features of PpNATR76 lncRNAs make them very similar with the recently discovered human lncRNAs, raising a number of questions for future studies. This work provides new resources for functional studies of satellitome in plants using the model organism P.patens, and describes a list of tandem repeats for further analysis.
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Affiliation(s)
- Ilya Kirov
- Laboratory of functional genomics and proteomics of plants, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russian FederationShemyakin and Ovchinnikov Institute of Bioorganic ChemistryMoscowRussia
| | - Marina Gilyok
- Laboratory of functional genomics and proteomics of plants, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russian FederationShemyakin and Ovchinnikov Institute of Bioorganic ChemistryMoscowRussia
| | - Andrey Knyazev
- Laboratory of functional genomics and proteomics of plants, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russian FederationShemyakin and Ovchinnikov Institute of Bioorganic ChemistryMoscowRussia
| | - Igor Fesenko
- Laboratory of functional genomics and proteomics of plants, Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russian FederationShemyakin and Ovchinnikov Institute of Bioorganic ChemistryMoscowRussia
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16
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Batra R, Nelles DA, Pirie E, Blue SM, Marina RJ, Wang H, Chaim IA, Thomas JD, Zhang N, Nguyen V, Aigner S, Markmiller S, Xia G, Corbett KD, Swanson MS, Yeo GW. Elimination of Toxic Microsatellite Repeat Expansion RNA by RNA-Targeting Cas9. Cell 2017; 170:899-912.e10. [PMID: 28803727 DOI: 10.1016/j.cell.2017.07.010] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/11/2017] [Accepted: 07/11/2017] [Indexed: 12/13/2022]
Abstract
Microsatellite repeat expansions in DNA produce pathogenic RNA species that cause dominantly inherited diseases such as myotonic dystrophy type 1 and 2 (DM1/2), Huntington's disease, and C9orf72-linked amyotrophic lateral sclerosis (C9-ALS). Means to target these repetitive RNAs are required for diagnostic and therapeutic purposes. Here, we describe the development of a programmable CRISPR system capable of specifically visualizing and eliminating these toxic RNAs. We observe specific targeting and efficient elimination of microsatellite repeat expansion RNAs both when exogenously expressed and in patient cells. Importantly, RNA-targeting Cas9 (RCas9) reverses hallmark features of disease including elimination of RNA foci among all conditions studied (DM1, DM2, C9-ALS, polyglutamine diseases), reduction of polyglutamine protein products, relocalization of repeat-bound proteins to resemble healthy controls, and efficient reversal of DM1-associated splicing abnormalities in patient myotubes. Finally, we report a truncated RCas9 system compatible with adeno-associated viral packaging. This effort highlights the potential of RCas9 for human therapeutics.
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Affiliation(s)
- Ranjan Batra
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - David A Nelles
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Elaine Pirie
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Steven M Blue
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Ryan J Marina
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Harrison Wang
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Isaac A Chaim
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - James D Thomas
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, USA
| | - Nigel Zhang
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Vu Nguyen
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Stefan Aigner
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Sebastian Markmiller
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Guangbin Xia
- Department of Neurology, University of Florida, College of Medicine, Gainesville, FL, USA
| | - Kevin D Corbett
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA; Department of Chemistry, University of California, San Diego, La Jolla, CA, USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Stem Cell Program, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA; Molecular Engineering Laboratory, A(∗)STAR, Singapore, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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17
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Expanded CCUG repeat RNA expression in Drosophila heart and muscle trigger Myotonic Dystrophy type 1-like phenotypes and activate autophagocytosis genes. Sci Rep 2017; 7:2843. [PMID: 28588248 PMCID: PMC5460254 DOI: 10.1038/s41598-017-02829-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 04/19/2017] [Indexed: 12/12/2022] Open
Abstract
Myotonic dystrophies (DM1–2) are neuromuscular genetic disorders caused by the pathological expansion of untranslated microsatellites. DM1 and DM2, are caused by expanded CTG repeats in the 3′UTR of the DMPK gene and CCTG repeats in the first intron of the CNBP gene, respectively. Mutant RNAs containing expanded repeats are retained in the cell nucleus, where they sequester nuclear factors and cause alterations in RNA metabolism. However, for unknown reasons, DM1 is more severe than DM2. To study the differences and similarities in the pathogenesis of DM1 and DM2, we generated model flies by expressing pure expanded CUG ([250]×) or CCUG ([1100]×) repeats, respectively, and compared them with control flies expressing either 20 repeat units or GFP. We observed surprisingly severe muscle reduction and cardiac dysfunction in CCUG-expressing model flies. The muscle and cardiac tissue of both DM1 and DM2 model flies showed DM1-like phenotypes including overexpression of autophagy-related genes, RNA mis-splicing and repeat RNA aggregation in ribonuclear foci along with the Muscleblind protein. These data reveal, for the first time, that expanded non-coding CCUG repeat-RNA has similar in vivo toxicity potential as expanded CUG RNA in muscle and heart tissues and suggests that specific, as yet unknown factors, quench CCUG-repeat toxicity in DM2 patients.
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18
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Sahashi K, Hashizume A, Sobue G, Katsuno M. Progress toward the development of treatment of spinal and bulbar muscular atrophy. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1329088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Kentaro Sahashi
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Atsushi Hashizume
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Gen Sobue
- Research Division of Dementia and Neurodegenerative Disease, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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19
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Cleary JD, Ranum LP. New developments in RAN translation: insights from multiple diseases. Curr Opin Genet Dev 2017; 44:125-134. [PMID: 28365506 PMCID: PMC5951168 DOI: 10.1016/j.gde.2017.03.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 02/28/2017] [Accepted: 03/13/2017] [Indexed: 12/14/2022]
Abstract
Since the discovery of repeat-associated non-ATG (RAN) translation, and more recently its association with amyotrophic lateral sclerosis/frontotemporal dementia, there has been an intense focus to understand how this process works and the downstream effects of these novel proteins. RAN translation across several different types of repeat expansions mutations (CAG, CTG, CCG, GGGGCC, GGCCCC) results in the production of proteins in all three reading frames without an ATG initiation codon. The combination of bidirectional transcription and RAN translation has been shown to result in the accumulation of up to six mutant expansion proteins in a growing number of diseases. This process is complex mechanistically and also complex from the perspective of the downstream consequences in disease. Here we review recent developments in RAN translation and their implications on our basic understanding of neurodegenerative disease and gene expression.
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Affiliation(s)
- John Douglas Cleary
- Center for NeuroGenetics, University of Florida, Gainesville, FL, USA; Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA; Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Laura Pw Ranum
- Center for NeuroGenetics, University of Florida, Gainesville, FL, USA; Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA; Department of Neurology, University of Florida, Gainesville, FL, USA; Genetics Institute, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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20
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Morriss GR, Cooper TA. Protein sequestration as a normal function of long noncoding RNAs and a pathogenic mechanism of RNAs containing nucleotide repeat expansions. Hum Genet 2017; 136:1247-1263. [PMID: 28484853 DOI: 10.1007/s00439-017-1807-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/28/2017] [Indexed: 12/12/2022]
Abstract
An emerging class of long noncoding RNAs (lncRNAs) function as decoy molecules that bind and sequester proteins thereby inhibiting their normal functions. Titration of proteins by lncRNAs has wide-ranging effects affecting nearly all steps in gene expression. While decoy lncRNAs play a role in normal physiology, RNAs expressed from alleles containing nucleotide repeat expansions can be pathogenic due to protein sequestration resulting in disruption of normal functions. This review focuses on commonalities between decoy lncRNAs that regulate gene expression by competitive inhibition of protein function through sequestration and specific examples of nucleotide repeat expansion disorders mediated by toxic RNA that sequesters RNA-binding proteins and impedes their normal functions. Understanding how noncoding RNAs compete with various RNA and DNA molecules for binding of regulatory proteins will provide insight into how similar mechanisms contribute to disease pathogenesis.
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Affiliation(s)
- Ginny R Morriss
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Thomas A Cooper
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA. .,Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, 77030, USA.
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21
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C9orf72 BAC Mouse Model with Motor Deficits and Neurodegenerative Features of ALS/FTD. Neuron 2016; 90:521-34. [DOI: 10.1016/j.neuron.2016.04.005] [Citation(s) in RCA: 245] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/01/2016] [Accepted: 03/29/2016] [Indexed: 12/12/2022]
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22
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Abstract
The human transcriptome is composed of a vast RNA population that undergoes further diversification by splicing. Detecting specific splice sites in this large sequence pool is the responsibility of the major and minor spliceosomes in collaboration with numerous splicing factors. This complexity makes splicing susceptible to sequence polymorphisms and deleterious mutations. Indeed, RNA mis-splicing underlies a growing number of human diseases with substantial societal consequences. Here, we provide an overview of RNA splicing mechanisms followed by a discussion of disease-associated errors, with an emphasis on recently described mutations that have provided new insights into splicing regulation. We also discuss emerging strategies for splicing-modulating therapy.
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Affiliation(s)
- Marina M Scotti
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida 32610-3610 USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida 32610-3610 USA
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23
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Goodwin M, Mohan A, Batra R, Lee KY, Charizanis K, Fernández Gómez FJ, Eddarkaoui S, Sergeant N, Buée L, Kimura T, Clark HB, Dalton J, Takamura K, Weyn-Vanhentenryck SM, Zhang C, Reid T, Ranum LPW, Day JW, Swanson MS. MBNL Sequestration by Toxic RNAs and RNA Misprocessing in the Myotonic Dystrophy Brain. Cell Rep 2015; 12:1159-68. [PMID: 26257173 DOI: 10.1016/j.celrep.2015.07.029] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/24/2015] [Accepted: 07/14/2015] [Indexed: 11/19/2022] Open
Abstract
For some neurological disorders, disease is primarily RNA mediated due to expression of non-coding microsatellite expansion RNAs (RNA(exp)). Toxicity is thought to result from enhanced binding of proteins to these expansions and depletion from their normal cellular targets. However, experimental evidence for this sequestration model is lacking. Here, we use HITS-CLIP and pre-mRNA processing analysis of human control versus myotonic dystrophy (DM) brains to provide compelling evidence for this RNA toxicity model. MBNL2 binds directly to DM repeat expansions in the brain, resulting in depletion from its normal RNA targets with downstream effects on alternative splicing and polyadenylation. Similar RNA processing defects were detected in Mbnl compound-knockout mice, highlighted by dysregulation of Mapt splicing and fetal tau isoform expression in adults. These results demonstrate that MBNL proteins are directly sequestered by RNA(exp) in the DM brain and introduce a powerful experimental tool to evaluate RNA-mediated toxicity in other expansion diseases.
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Affiliation(s)
- Marianne Goodwin
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Apoorva Mohan
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Ranjan Batra
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Kuang-Yung Lee
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Department of Neurology, Chang Gung Memorial Hospital, Keelung 20401, Taiwan
| | - Konstantinos Charizanis
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA; InSiliGen LLC, Gainesville, FL 32606, USA
| | - Francisco José Fernández Gómez
- Inserm UMR S1172, Alzheimer and Tauopathies, Université Lille Nord de France, Centre Jean-Pierre Aubert, 1 Place Verdun, 59045 Lille, France
| | - Sabiha Eddarkaoui
- Inserm UMR S1172, Alzheimer and Tauopathies, Université Lille Nord de France, Centre Jean-Pierre Aubert, 1 Place Verdun, 59045 Lille, France
| | - Nicolas Sergeant
- Inserm UMR S1172, Alzheimer and Tauopathies, Université Lille Nord de France, Centre Jean-Pierre Aubert, 1 Place Verdun, 59045 Lille, France
| | - Luc Buée
- Inserm UMR S1172, Alzheimer and Tauopathies, Université Lille Nord de France, Centre Jean-Pierre Aubert, 1 Place Verdun, 59045 Lille, France
| | - Takashi Kimura
- Division of Neurology, Department of Internal Medicine, Hyogo College of Medicine, Hyogo 663-8501, Japan
| | - H Brent Clark
- Departments of Laboratory Medicine and Pathology, Neurology, Neurosurgery, and Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Joline Dalton
- Departments of Laboratory Medicine and Pathology, Neurology, Neurosurgery, and Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Kenji Takamura
- Departments of Laboratory Medicine and Pathology, Neurology, Neurosurgery, and Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Sebastien M Weyn-Vanhentenryck
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Chaolin Zhang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | - Tammy Reid
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Laura P W Ranum
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - John W Day
- Department of Neurology and Neurological Sciences, School of Medicine, Stanford University, Palo Alto, CA 94305, USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
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