1
|
Verbeeren J, Teixeira J, Garcia SMDA. The Muscleblind-like protein MBL-1 regulates microRNA expression in Caenorhabditis elegans through an evolutionarily conserved autoregulatory mechanism. PLoS Genet 2023; 19:e1011109. [PMID: 38134228 PMCID: PMC10773944 DOI: 10.1371/journal.pgen.1011109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 01/08/2024] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
The Muscleblind-like (MBNL) family is a highly conserved set of RNA-binding proteins (RBPs) that regulate RNA metabolism during the differentiation of various animal tissues. Functional insufficiency of MBNL affects muscle and central nervous system development, and contributes to the myotonic dystrophies (DM), a set of incurable multisystemic disorders. Studies on the regulation of MBNL genes are essential to provide insight into the gene regulatory networks controlled by MBNL proteins and to understand how dysregulation within these networks causes disease. In this study, we demonstrate the evolutionary conservation of an autoregulatory mechanism that governs the function of MBNL proteins by generating two distinct protein isoform types through alternative splicing. Our aim was to further our understanding of the regulatory principles that underlie this conserved feedback loop in a whole-organismal context, and to address the biological significance of the respective isoforms. Using an alternative splicing reporter, our studies show that, during development of the Caenorhabditis elegans central nervous system, the orthologous mbl-1 gene shifts production from long protein isoforms that localize to the nucleus to short isoforms that also localize to the cytoplasm. Using isoform-specific CRISPR/Cas9-generated strains, we showed that expression of short MBL-1 protein isoforms is required for healthy neuromuscular function and neurodevelopment, while expression of long MBL-1 protein isoforms is dispensable, emphasizing a key role for cytoplasmic functionalities of the MBL-1 protein. Furthermore, RNA-seq and lifespan analyses indicated that short MBL-1 isoforms are crucial regulators of miRNA expression and, in consequence, required for normal lifespan. In conclusion, this study provides support for the disruption of cytoplasmic RNA metabolism as a contributor in myotonic dystrophy and paves the way for further exploration of miRNA regulation through MBNL proteins during development and in disease models.
Collapse
Affiliation(s)
- Jens Verbeeren
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Joana Teixeira
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
| | | |
Collapse
|
2
|
Braun M, Shoshani S, Teixeira J, Mellul Shtern A, Miller M, Granot Z, Fischer SE, Garcia SMA, Tabach Y. Asymmetric inheritance of RNA toxicity in C. elegans expressing CTG repeats. iScience 2022; 25:104246. [PMID: 35494247 PMCID: PMC9051633 DOI: 10.1016/j.isci.2022.104246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/01/2022] [Accepted: 04/07/2022] [Indexed: 11/18/2022] Open
Abstract
Nucleotide repeat expansions are a hallmark of over 40 neurodegenerative diseases and cause RNA toxicity and multisystemic symptoms that worsen with age. Through an unclear mechanism, RNA toxicity can trigger severe disease manifestation in infants if the repeats are inherited from their mother. Here we use Caenorhabditis elegans bearing expanded CUG repeats to show that this asymmetric intergenerational inheritance of toxicity contributes to disease pathogenesis. In addition, we show that this mechanism is dependent on small RNA pathways with maternal repeat-derived small RNAs causing transcriptomic changes in the offspring, reduced motility, and shortened lifespan. We rescued the toxicity phenotypes in the offspring by perturbing the RNAi machinery in the affected hermaphrodites. This points to a novel mechanism linking maternal bias and the RNAi machinery and suggests that toxic RNA is transmitted to offspring, causing disease phenotypes through intergenerational epigenetic inheritance. Maternal origin of expanded CUG repeats induces RNA toxicity in Caenorhabditis elegans offspring Offspring of affected hermaphrodites show molecular and phenotypic disease phenotypes The RNAi machinery is directly related to the maternal inheritance of RNA toxicity Altering the RNAi machinery in affected hermaphrodites rescues toxicity in offspring
Collapse
Affiliation(s)
- Maya Braun
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Shachar Shoshani
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Joana Teixeira
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790 Finland
| | - Anna Mellul Shtern
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Maya Miller
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Zvi Granot
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Sylvia E.J. Fischer
- Division of Infectious Diseases, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Susana M.D. A. Garcia
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790 Finland
- Corresponding author
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Corresponding author
| |
Collapse
|
3
|
Aurintricarboxylic Acid Decreases RNA Toxicity in a C. elegans Model of Repeat Expansions. Toxins (Basel) 2021; 13:toxins13120910. [PMID: 34941747 PMCID: PMC8706575 DOI: 10.3390/toxins13120910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/06/2021] [Accepted: 12/17/2021] [Indexed: 11/30/2022] Open
Abstract
Pathologic expansions of DNA nucleotide tandem repeats may generate toxic RNA that triggers disease phenotypes. RNA toxicity is the hallmark of multiple expansion repeat disorders, including myotonic dystrophy type 1 (DM1). To date, there are no available disease-modifying therapies for DM1. Our aim was to use drug repositioning to ameliorate the phenotype of affected individuals in a nematode model of DM1. As the RNA interference pathway plays a key role in mediating RNA toxicity, we investigated the effect of aurintricarboxylic acid. We demonstrated that by perturbing the RNA interference machinery using aurintricarboxylic acid, we could annihilate the RNA toxicity and ameliorate the phenotype. As our approach targets a universal disease mechanism, it is potentially relevant for more expansion repeat disorders.
Collapse
|
4
|
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.
Collapse
|
5
|
Matilainen O, Ribeiro ARS, Verbeeren J, Cetinbas M, Sood H, Sadreyev RI, Garcia SMDA. Loss of muscleblind splicing factor shortens Caenorhabditis elegans lifespan by reducing the activity of p38 MAPK/PMK-1 and transcription factors ATF-7 and Nrf/SKN-1. Genetics 2021; 219:6325509. [PMID: 34849877 PMCID: PMC8633093 DOI: 10.1093/genetics/iyab114] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 07/03/2021] [Indexed: 12/13/2022] Open
Abstract
Muscleblind-like splicing regulators (MBNLs) are RNA-binding factors that have an important role in developmental processes. Dysfunction of these factors is a key contributor of different neuromuscular degenerative disorders, including Myotonic Dystrophy type 1 (DM1). Since DM1 is a multisystemic disease characterized by symptoms resembling accelerated aging, we asked which cellular processes do MBNLs regulate that make them necessary for normal lifespan. By utilizing the model organism Caenorhabditis elegans, we found that loss of MBL-1 (the sole ortholog of mammalian MBNLs), which is known to be required for normal lifespan, shortens lifespan by decreasing the activity of p38 MAPK/PMK-1 as well as the function of transcription factors ATF-7 and SKN-1. Furthermore, we show that mitochondrial stress caused by the knockdown of mitochondrial electron transport chain components promotes the longevity of mbl-1 mutants in a partially PMK-1-dependent manner. Together, the data establish a mechanism of how DM1-associated loss of muscleblind affects lifespan. Furthermore, this study suggests that mitochondrial stress could alleviate symptoms caused by the dysfunction of muscleblind splicing factor, creating a potential approach to investigate for therapy.
Collapse
Affiliation(s)
- Olli Matilainen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Ana R S Ribeiro
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Jens Verbeeren
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Murat Cetinbas
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Heini Sood
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Susana M D A Garcia
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki 00790, Finland
| |
Collapse
|
6
|
A CTG repeat-selective chemical screen identifies microtubule inhibitors as selective modulators of toxic CUG RNA levels. Proc Natl Acad Sci U S A 2019; 116:20991-21000. [PMID: 31570586 DOI: 10.1073/pnas.1901893116] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
A CTG repeat expansion in the DMPK gene is the causative mutation of myotonic dystrophy type 1 (DM1). Transcription of the expanded CTG repeat produces toxic gain-of-function CUG RNA, leading to disease symptoms. A screening platform that targets production or stability of the toxic CUG RNA in a selective manner has the potential to provide new biological and therapeutic insights. A DM1 HeLa cell model was generated that stably expresses a toxic r(CUG)480 and an analogous r(CUG)0 control from DMPK and was used to measure the ratio-metric level of r(CUG)480 versus r(CUG)0. This DM1 HeLa model recapitulates pathogenic hallmarks of DM1, including CUG ribonuclear foci and missplicing of pre-mRNA targets of the muscleblind (MBNL) alternative splicing factors. Repeat-selective screening using this cell line led to the unexpected identification of multiple microtubule inhibitors as hits that selectively reduce r(CUG)480 levels and partially rescue MBNL-dependent missplicing. These results were validated by using the Food and Drug Administration-approved clinical microtubule inhibitor colchicine in DM1 mouse and primary patient cell models. The mechanism of action was found to involve selective reduced transcription of the CTG expansion that we hypothesize to involve the LINC (linker of nucleoskeleton and cytoskeleton) complex. The unanticipated identification of microtubule inhibitors as selective modulators of toxic CUG RNA opens research directions for this form of muscular dystrophy and may shed light on the biology of CTG repeat expansion and inform therapeutic avenues. This approach has the potential to identify modulators of expanded repeat-containing gene expression for over 30 microsatellite expansion disorders.
Collapse
|
7
|
Qawasmi L, Braun M, Guberman I, Cohen E, Naddaf L, Mellul A, Matilainen O, Roitenberg N, Share D, Stupp D, Chahine H, Cohen E, Garcia SM, Tabach Y. Expanded CUG Repeats Trigger Disease Phenotype and Expression Changes through the RNAi Machinery in C. elegans. J Mol Biol 2019; 431:1711-1728. [DOI: 10.1016/j.jmb.2019.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/28/2019] [Accepted: 03/07/2019] [Indexed: 11/26/2022]
|
8
|
Nikonova E, Kao SY, Ravichandran K, Wittner A, Spletter ML. Conserved functions of RNA-binding proteins in muscle. Int J Biochem Cell Biol 2019; 110:29-49. [PMID: 30818081 DOI: 10.1016/j.biocel.2019.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 02/21/2019] [Accepted: 02/23/2019] [Indexed: 12/13/2022]
Abstract
Animals require different types of muscle for survival, for example for circulation, motility, reproduction and digestion. Much emphasis in the muscle field has been placed on understanding how transcriptional regulation generates diverse types of muscle during development. Recent work indicates that alternative splicing and RNA regulation are as critical to muscle development, and altered function of RNA-binding proteins causes muscle disease. Although hundreds of genes predicted to bind RNA are expressed in muscles, many fewer have been functionally characterized. We present a cross-species view summarizing what is known about RNA-binding protein function in muscle, from worms and flies to zebrafish, mice and humans. In particular, we focus on alternative splicing regulated by the CELF, MBNL and RBFOX families of proteins. We discuss the systemic nature of diseases associated with loss of RNA-binding proteins in muscle, focusing on mis-regulation of CELF and MBNL in myotonic dystrophy. These examples illustrate the conservation of RNA-binding protein function and the marked utility of genetic model systems in understanding mechanisms of RNA regulation.
Collapse
Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Keshika Ravichandran
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Anja Wittner
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany
| | - Maria L Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-University München, Großhaderner Str. 9, 82152, Martinsried-Planegg, Germany; Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
| |
Collapse
|
9
|
Omar I, Guterman-Ram G, Rahat D, Tabach Y, Berger M, Levaot N. Schlafen2 mutation in mice causes an osteopetrotic phenotype due to a decrease in the number of osteoclast progenitors. Sci Rep 2018; 8:13005. [PMID: 30158544 PMCID: PMC6115409 DOI: 10.1038/s41598-018-31428-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/30/2018] [Indexed: 01/14/2023] Open
Abstract
Osteoclasts are the bone resorbing cells that derive from myeloid progenitor cells. Although there have been recent advancements in the ability to identify osteoclast progenitors, very little is known about the molecular mechanisms governing their homeostasis. Here, by analyzing the normalized phylogenetic profiles of the Schlafen (Slfn) gene family, we found that it co-evolved with osteoclast-related genes. Following these findings, we used a Slfn2 loss-of-function mutant mouse, elektra, to study the direct role of Slfn2 in osteoclast development and function. Slfn2eka/eka mice exhibited a profound increase in their cancellous bone mass and a significant reduction in osteoclast numbers. In addition, monocyte cultures from the bone marrow of Slfn2eka/eka mice showed a reduction in osteoclast number and total resorption area. Finally, we show that the bone marrow of Slfn2eka/eka mice have significantly less CD11b-Ly6Chi osteoclast precursors. Overall, our data suggest that Slfn2 is required for normal osteoclast differentiation and that loss of its function in mice results in an osteopetrotic phenotype.
Collapse
Affiliation(s)
- Ibrahim Omar
- The Lautenberg Center for Immunology and Cancer Research, The Biomedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School Jerusalem, Jerusalem, Israel
| | - Gali Guterman-Ram
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Dolev Rahat
- Department of Developmental Biology and Cancer Research, The Biomedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School Jerusalem, Jerusalem, Israel
| | - Yuval Tabach
- Department of Developmental Biology and Cancer Research, The Biomedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School Jerusalem, Jerusalem, Israel
| | - Michael Berger
- The Lautenberg Center for Immunology and Cancer Research, The Biomedical Research Institute Israel Canada of the Faculty of Medicine, The Hebrew University Hadassah Medical School Jerusalem, Jerusalem, Israel.
| | - Noam Levaot
- Department of Physiology and Cell Biology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| |
Collapse
|
10
|
Braz SO, Acquaire J, Gourdon G, Gomes-Pereira M. Of Mice and Men: Advances in the Understanding of Neuromuscular Aspects of Myotonic Dystrophy. Front Neurol 2018; 9:519. [PMID: 30050493 PMCID: PMC6050950 DOI: 10.3389/fneur.2018.00519] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Accepted: 06/12/2018] [Indexed: 12/26/2022] Open
Abstract
Intensive effort has been directed toward the modeling of myotonic dystrophy (DM) in mice, in order to reproduce human disease and to provide useful tools to investigate molecular and cellular pathogenesis and test efficient therapies. Mouse models have contributed to dissect the multifaceted impact of the DM mutation in various tissues, cell types and in a pleiotropy of pathways, through the expression of toxic RNA transcripts. Changes in alternative splicing, transcription, translation, intracellular RNA localization, polyadenylation, miRNA metabolism and phosphorylation of disease intermediates have been described in different tissues. Some of these events have been directly associated with specific disease symptoms in the skeletal muscle and heart of mice, offering the molecular explanation for individual disease phenotypes. In the central nervous system (CNS), however, the situation is more complex. We still do not know how the molecular abnormalities described translate into CNS dysfunction, nor do we know if the correction of individual molecular events will provide significant therapeutic benefits. The variability in model design and phenotypes described so far requires a thorough and critical analysis. In this review we discuss the recent contributions of mouse models to the understanding of neuromuscular aspects of disease, therapy development, and we provide a reflective assessment of our current limitations and pressing questions that remain unanswered.
Collapse
Affiliation(s)
- Sandra O Braz
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Julien Acquaire
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Geneviève Gourdon
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Mário Gomes-Pereira
- Laboratory CTGDM, INSERM UMR1163, Paris, France.,Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| |
Collapse
|
11
|
Rohilla KJ, Gagnon KT. RNA biology of disease-associated microsatellite repeat expansions. Acta Neuropathol Commun 2017; 5:63. [PMID: 28851463 PMCID: PMC5574247 DOI: 10.1186/s40478-017-0468-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/22/2017] [Indexed: 12/13/2022] Open
Abstract
Microsatellites, or simple tandem repeat sequences, occur naturally in the human genome and have important roles in genome evolution and function. However, the expansion of microsatellites is associated with over two dozen neurological diseases. A common denominator among the majority of these disorders is the expression of expanded tandem repeat-containing RNA, referred to as xtrRNA in this review, which can mediate molecular disease pathology in multiple ways. This review focuses on the potential impact that simple tandem repeat expansions can have on the biology and metabolism of RNA that contain them and underscores important gaps in understanding. Merging the molecular biology of repeat expansion disorders with the current understanding of RNA biology, including splicing, transcription, transport, turnover and translation, will help clarify mechanisms of disease and improve therapeutic development.
Collapse
|
12
|
Urbanek MO, Krzyzosiak WJ. Discriminating RNA variants with single-molecule allele-specific FISH. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:230-241. [DOI: 10.1016/j.mrrev.2016.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 10/21/2022]
|
13
|
Zhang N, Ashizawa T. RNA toxicity and foci formation in microsatellite expansion diseases. Curr Opin Genet Dev 2017; 44:17-29. [PMID: 28208060 DOI: 10.1016/j.gde.2017.01.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/04/2017] [Accepted: 01/18/2017] [Indexed: 12/11/2022]
Abstract
More than 30 incurable neurological and neuromuscular diseases are caused by simple microsatellite expansions consisted of 3-6 nucleotides. These repeats can occur in non-coding regions and often result in a dominantly inherited disease phenotype that is characteristic of a toxic RNA gain-of-function. The expanded RNA adopts unusual secondary structures, sequesters various RNA binding proteins to form insoluble nuclear foci, and causes cellular defects at a multisystem level. Nuclear foci are dynamic in size, shape and colocalization of RNA binding proteins in different expansion diseases and tissue types. This review sets to provide new insights into the disease mechanisms of RNA toxicity and foci modulation, in light of recent advancement on bi-directional transcription, antisense RNA, repeat-associated non-ATG translation and beyond.
Collapse
Affiliation(s)
- Nan Zhang
- Neurosciences Research Program, Houston Methodist Research Institute, Houston, TX 77030, United States; Division of Cell and Molecular Biology, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - Tetsuo Ashizawa
- Neurosciences Research Program, Houston Methodist Research Institute, Houston, TX 77030, United States.
| |
Collapse
|
14
|
Urbanek MO, Krzyzosiak WJ. RNA FISH for detecting expanded repeats in human diseases. Methods 2015; 98:115-123. [PMID: 26615955 DOI: 10.1016/j.ymeth.2015.11.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/18/2015] [Accepted: 11/21/2015] [Indexed: 12/14/2022] Open
Abstract
RNA fluorescence in situ hybridization (FISH) is a widely used technique for detecting transcripts in fixed cells and tissues. Many variants of RNA FISH have been proposed to increase signal strength, resolution and target specificity. The current variants of this technique facilitate the detection of the subcellular localization of transcripts at a single molecule level. Among the applications of RNA FISH are studies on nuclear RNA foci in diseases resulting from the expansion of tri-, tetra-, penta- and hexanucleotide repeats present in different single genes. The partial or complete retention of mutant transcripts forming RNA aggregates within the nucleoplasm has been shown in multiple cellular disease models and in the tissues of patients affected with these atypical mutations. Relevant diseases include, among others, myotonic dystrophy type 1 (DM1) with CUG repeats, Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) with CAG repeats, fragile X-associated tremor/ataxia syndrome (FXTAS) with CGG repeats, myotonic dystrophy type 2 (DM2) with CCUG repeats, amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD) with GGGGCC repeats and spinocerebellar ataxia type 32 (SCA32) with GGCCUG. In this article, we summarize the results obtained with FISH to examine RNA nuclear inclusions. We provide a detailed protocol for detecting RNAs containing expanded CAG and CUG repeats in different cellular models, including fibroblasts, lymphoblasts, induced pluripotent stem cells and murine and human neuronal progenitors. We also present the results of the first single-molecule FISH application in a cellular model of polyglutamine disease.
Collapse
Affiliation(s)
- Martyna O Urbanek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
| |
Collapse
|
15
|
Pettersson OJ, Aagaard L, Jensen TG, Damgaard CK. Molecular mechanisms in DM1 - a focus on foci. Nucleic Acids Res 2015; 43:2433-41. [PMID: 25605794 PMCID: PMC4344492 DOI: 10.1093/nar/gkv029] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 01/05/2015] [Accepted: 01/11/2015] [Indexed: 01/15/2023] Open
Abstract
Myotonic dystrophy type 1 is caused by abnormal expansion of a CTG-trinucleotide repeat in the gene encoding Dystrophia Myotonica Protein Kinase (DMPK), which in turn leads to global deregulation of gene expression in affected individuals. The transcribed mRNA contains a massive CUG-expansion in the 3' untranslated region (3'UTR) facilitating nucleation of several regulatory RNA-binding proteins, which are thus unable to perform their normal cellular function. These CUG-expanded mRNA-protein aggregates form distinct, primarily nuclear foci. In differentiated muscle cells, most of the CUG-expanded RNA remains in the nuclear compartment, while in dividing cells such as fibroblasts a considerable fraction of the mutant RNA reaches the cytoplasm, consistent with findings that both nuclear and cytoplasmic events are mis-regulated in DM1. Recent evidence suggests that the nuclear aggregates, or ribonuclear foci, are more dynamic than previously anticipated and regulated by several proteins, including RNA helicases. In this review, we focus on the homeostasis of DMPK mRNA foci and discuss how their dynamic regulation may affect disease-causing mechanisms in DM1.
Collapse
Affiliation(s)
- Olof Joakim Pettersson
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, Building 1240, DK-8000 Aarhus C, Denmark
| | - Lars Aagaard
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, Building 1240, DK-8000 Aarhus C, Denmark
| | - Thomas Gryesten Jensen
- Department of Biomedicine, Aarhus University, Wilhelm Meyers Allé 4, Building 1240, DK-8000 Aarhus C, Denmark
| | - Christian Kroun Damgaard
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, DK-8000 Aarhus C, Denmark
| |
Collapse
|
16
|
Shetty SP, Copeland PR. Selenocysteine incorporation: A trump card in the game of mRNA decay. Biochimie 2015; 114:97-101. [PMID: 25622574 DOI: 10.1016/j.biochi.2015.01.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 01/14/2015] [Indexed: 11/16/2022]
Abstract
The incorporation of the 21st amino acid, selenocysteine (Sec), occurs on mRNAs that harbor in-frame stop codons because the Sec-tRNA(Sec) recognizes a UGA codon. This sets up an intriguing interplay between translation elongation, translation termination and the complex machinery that marks mRNAs that contain premature termination codons for degradation, leading to nonsense mediated mRNA decay (NMD). In this review we discuss the intricate and complex relationship between this key quality control mechanism and the process of Sec incorporation in mammals.
Collapse
Affiliation(s)
- Sumangala P Shetty
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Ln, Piscataway, NJ 08854, USA
| | - Paul R Copeland
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, 675 Hoes Ln, Piscataway, NJ 08854, USA.
| |
Collapse
|
17
|
Chau A, Kalsotra A. Developmental insights into the pathology of and therapeutic strategies for DM1: Back to the basics. Dev Dyn 2015; 244:377-90. [PMID: 25504326 DOI: 10.1002/dvdy.24240] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/25/2014] [Accepted: 11/27/2014] [Indexed: 12/25/2022] Open
Abstract
Myotonic Dystrophy type 1 (DM1), the most prevalent adult onset muscular dystrophy, is a trinucleotide repeat expansion disease caused by CTG expansion in the 3'-UTR of DMPK gene. This expansion results in the expression of toxic gain-of-function RNA that forms ribonuclear foci and disrupts normal activities of RNA-binding proteins belonging to the MBNL and CELF families. Changes in alternative splicing, translation, localization, and mRNA stability due to sequestration of MBNL proteins and up-regulation of CELF1 are key to DM1 pathology. However, recent discoveries indicate that pathogenic mechanisms of DM1 involves many other factors as well, including repeat associated translation, activation of PKC-dependent signaling pathway, aberrant polyadenylation, and microRNA deregulation. Expression of the toxic repeat RNA culminates in the developmental remodeling of the transcriptome, which produces fetal isoforms of proteins that are unable to fulfill the physiological requirements of adult tissues. This review will describe advances in the understanding of DM1 pathogenesis as well as current therapeutic developments for DM1.
Collapse
Affiliation(s)
- Anthony Chau
- Department of Biochemistry, University of Illinois, Urbana-Champaign, Illinois; Department of Medical Biochemistry, University of Illinois, Urbana-Champaign, Illinois; Institute of Genomic Biology, University of Illinois, Urbana-Champaign, Illinois
| | | |
Collapse
|