101
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Koon AC, Chan HYE. Drosophila melanogaster As a Model Organism to Study RNA Toxicity of Repeat Expansion-Associated Neurodegenerative and Neuromuscular Diseases. Front Cell Neurosci 2017; 11:70. [PMID: 28377694 PMCID: PMC5359753 DOI: 10.3389/fncel.2017.00070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/27/2017] [Indexed: 12/14/2022] Open
Abstract
For nearly a century, the fruit fly, Drosophila melanogaster, has proven to be a valuable tool in our understanding of fundamental biological processes, and has empowered our discoveries, particularly in the field of neuroscience. In recent years, Drosophila has emerged as a model organism for human neurodegenerative and neuromuscular disorders. In this review, we highlight a number of recent studies that utilized the Drosophila model to study repeat-expansion associated diseases (READs), such as polyglutamine diseases, fragile X-associated tremor/ataxia syndrome (FXTAS), myotonic dystrophy type 1 (DM1) and type 2 (DM2), and C9ORF72-associated amyotrophic lateral sclerosis/frontotemporal dementia (C9-ALS/FTD). Discoveries regarding the possible mechanisms of RNA toxicity will be focused here. These studies demonstrate Drosophila as an excellent in vivo model system that can reveal novel mechanistic insights into human disorders, providing the foundation for translational research and therapeutic development.
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Affiliation(s)
- Alex C Koon
- Laboratory of Drosophila ResearchHong Kong, Hong Kong; Biochemistry ProgramHong Kong, Hong Kong
| | - Ho Yin Edwin Chan
- Laboratory of Drosophila ResearchHong Kong, Hong Kong; Biochemistry ProgramHong Kong, Hong Kong; Cell and Molecular Biology ProgramHong Kong, Hong Kong; Molecular Biotechnology Program, Faculty of Science, School of Life SciencesHong Kong, Hong Kong; School of Life Sciences, Gerald Choa Neuroscience Centre, The Chinese University of Hong KongHong Kong, Hong Kong
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102
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Gass JM, McKay J, Guthrie KJ, Boczek N, Atwal PS, Van Gerpen J. A Case of Two Repeats: Huntington's Disease and Spinocerebellar Ataxia Type 8. Mov Disord Clin Pract 2017; 4:270-272. [DOI: 10.1002/mdc3.12401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 05/13/2016] [Accepted: 05/25/2016] [Indexed: 11/06/2022] Open
Affiliation(s)
- Jennifer M. Gass
- Center for Individualized Medicine Mayo Clinic Jacksonville Florida USA
| | - Jake McKay
- Department of Neurology Mayo Clinic Jacksonville Florida USA
| | - Kimberly J. Guthrie
- Center for Individualized Medicine Mayo Clinic Jacksonville Florida USA
- Department of Clinical Genomics Mayo Clinic Jacksonville Florida USA
| | - Nicole Boczek
- Division of Biomedical Statistics and Informatics Mayo Clinic Rochester Minnesota USA
| | - Paldeep S. Atwal
- Center for Individualized Medicine Mayo Clinic Jacksonville Florida USA
- Department of Clinical Genomics Mayo Clinic Jacksonville Florida USA
| | - Jay Van Gerpen
- Department of Neurology Mayo Clinic Jacksonville Florida USA
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103
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Cui X, Sun X, Niu W, Kong L, He M, Zhong A, Chen S, Jiang K, Zhang L, Cheng Z. Long Non-Coding RNA: Potential Diagnostic and Therapeutic Biomarker for Major Depressive Disorder. Med Sci Monit 2016; 22:5240-5248. [PMID: 28039689 PMCID: PMC5221417 DOI: 10.12659/msm.899372] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background The criteria for diagnosing depression are based on behavioral observation and self-reporting of symptoms by the patients or guardians without any biological validation of the disease. This study aimed to identify long non-coding RNAs (lncRNAs) in peripheral blood mononuclear cells (PBMCs) as robust and predictive biomarkers for diagnosis and therapy response in major depressive disorder (MDD). Material/Methods We used human lncRNA 3.0 microarray profiling (which covers 30,586 human lncRNAs), using PBMCs from five MDD patients and five controls. Differentially expressed lncRNAs in the PBMCs of MDD patients were identified, of which 10 candidate lncRNAs were selected for real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis in a larger cohort of 138 MDD patients and 63 healthy controls. Then among the 138 MDD patients who received standard antidepressant treatment, 30 were randomly selected for lncRNAs expression retesting and symptomatology assessments after three-weeks and six-weeks of antidepressant treatment. Results Six lncRNAs (TCONS_00019174, ENST00000566208, NONHSAG045500, ENST00000517573, NONHSAT034045, and NONHSAT142707) were significantly downregulated in MDD patients compared to control patients, and the area under the receiver operator curve (ROC) of these six lncRNAs cases, combined, was 0.719 (95% confidence interval (CI): 0.617–0.821). There was no difference in the expression of these six lncRNAs based on gender (p>0.05) or age (p>0.05). Conclusions These results suggest that the combined expression of six lncRNAs in PBMCs may serve as a potential biomarker for diagnosis and therapy response of MDD in the clinical setting.
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Affiliation(s)
- Xuelian Cui
- Department of Women Health Care, Changzhou Maternity and Child Health Care Hospital Affiliated with Nanjing Medical University, Changzhou, Jiangsu, China (mainland)
| | - Xinyang Sun
- Department of Psychology and Psychiatry, PingAn Health Cloud Company Ltd. of China, Shanghai, China (mainland)
| | - Wei Niu
- Department of Rehabilitation, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Lingming Kong
- Prevention and Treatment Center for Psychological Diseases, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Mingjun He
- Prevention and Treatment Center for Psychological Diseases, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Aifang Zhong
- Department of Laboratory, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Shengdong Chen
- Department of Neurology, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Kunhong Jiang
- Prevention and Treatment Center for Psychological Diseases, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Liyi Zhang
- Prevention and Treatment Center for Psychological Diseases, No. 102 Hospital of Chinese People's Liberation Army, Changzhou, Jiangsu, China (mainland)
| | - Zaohuo Cheng
- Wuxi Mental Health Center Affiliated with Nanjing Medical University, Wuxi, Jiangsu, China (mainland)
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104
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Alves-Cruzeiro JMDC, Mendonça L, Pereira de Almeida L, Nóbrega C. Motor Dysfunctions and Neuropathology in Mouse Models of Spinocerebellar Ataxia Type 2: A Comprehensive Review. Front Neurosci 2016; 10:572. [PMID: 28018166 PMCID: PMC5156697 DOI: 10.3389/fnins.2016.00572] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/28/2016] [Indexed: 12/16/2022] Open
Abstract
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant ataxia caused by an expansion of CAG repeats in the exon 1 of the gene ATXN2, conferring a gain of toxic function that triggers the appearance of the disease phenotype. SCA2 is characterized by several symptoms including progressive gait ataxia and dysarthria, slow saccadic eye movements, sleep disturbances, cognitive impairments, and psychological dysfunctions such as insomnia and depression, among others. The available treatments rely on palliative care, which mitigate some of the major symptoms but ultimately fail to block the disease progression. This persistent lack of effective therapies led to the development of several models in yeast, C. elegans, D. melanogaster, and mice to serve as platforms for testing new therapeutic strategies and to accelerate the research on the complex disease mechanisms. In this work, we review 4 transgenic and 1 knock-in mouse that exhibit a SCA2-related phenotype and discuss their usefulness in addressing different scientific problems. The knock-in mice are extremely faithful to the human disease, with late onset of symptoms and physiological levels of mutant ataxin-2, while the other transgenic possess robust and well-characterized motor impairments and neuropathological features. Furthermore, a new BAC model of SCA2 shows promise to study the recently explored role of non-coding RNAs as a major pathogenic mechanism in this devastating disorder. Focusing on specific aspects of the behavior and neuropathology, as well as technical aspects, we provide a highly practical description and comparison of all the models with the purpose of creating a useful resource for SCA2 researchers worldwide.
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Affiliation(s)
| | - Liliana Mendonça
- Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology, University of CoimbraCoimbra, Portugal; Faculty of Pharmacy, University of CoimbraCoimbra, Portugal
| | - Clévio Nóbrega
- Department of Biomedical Sciences and Medicine and Center for Biomedical Research, University of Algarve Faro, Portugal
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105
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Mandrile G, Di Gregorio E, Goel H, Giachino D, De Mercanti S, Iudicello M, Rolando M, Losa S, De Marchi M, Brusco A. Heterozygous Deletion of KLHL1/ATX8OS at the SCA8 Locus Is Unlikely Associated With Cerebellar Impairment in Humans. THE CEREBELLUM 2016; 15:208-12. [PMID: 25998497 DOI: 10.1007/s12311-015-0679-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Giorgia Mandrile
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
| | - Eleonora Di Gregorio
- Department of Medical Sciences, University of Torino, via Santena 19, Torino, 10126, Italy
- Medical Genetics, Città della Salute e della Scienza di Torino University Hospital, Torino, 10126, Italy
| | - Himanshu Goel
- Faculty of Health and Medicine, Callaghan and Hunter Genetics, University of Newcastle, Waratah, NSW2308, Australia
| | - Daniela Giachino
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
| | - Stefania De Mercanti
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
- Neurology Division, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
| | - Marco Iudicello
- Neurology Division, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
| | - Marco Rolando
- Azienda Sanitaria Locale TO3 di Collegno e Pinerolo, Neuropsichiatria Infantile, Collegno, 10093, Italy
| | - Sabrina Losa
- Azienda Sanitaria Locale TO3 di Collegno e Pinerolo, Neuropsichiatria Infantile, Collegno, 10093, Italy
| | - Mario De Marchi
- Medical Genetics, San Luigi Gonzaga University Hospital, Orbassano, 10043, Italy
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, 10043, Italy
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, via Santena 19, Torino, 10126, Italy.
- Medical Genetics, Città della Salute e della Scienza di Torino University Hospital, Torino, 10126, Italy.
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106
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Derepressing muscleblind expression by miRNA sponges ameliorates myotonic dystrophy-like phenotypes in Drosophila. Sci Rep 2016; 6:36230. [PMID: 27805016 PMCID: PMC5090246 DOI: 10.1038/srep36230] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 10/12/2016] [Indexed: 02/06/2023] Open
Abstract
Myotonic Dystrophy type 1 (DM1) originates from alleles of the DMPK gene with hundreds of extra CTG repeats in the 3′ untranslated region (3′ UTR). CUG repeat RNAs accumulate in foci that sequester Muscleblind-like (MBNL) proteins away from their functional target transcripts. Endogenous upregulation of MBNL proteins is, thus, a potential therapeutic approach to DM1. Here we identify two miRNAs, dme-miR-277 and dme-miR-304, that differentially regulate muscleblind RNA isoforms in miRNA sensor constructs. We also show that their sequestration by sponge constructs derepresses endogenous muscleblind not only in a wild type background but also in a DM1 Drosophila model expressing non-coding CUG trinucleotide repeats throughout the musculature. Enhanced muscleblind expression resulted in significant rescue of pathological phenotypes, including reversal of several mis-splicing events and reduced muscle atrophy in DM1 adult flies. Rescued flies had improved muscle function in climbing and flight assays, and had longer lifespan compared to disease controls. These studies provide proof of concept for a similar potentially therapeutic approach to DM1 in humans.
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107
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Tripathi BK, Surabhi S, Bhaskar PK, Mukherjee A, Mutsuddi M. The RNA binding KH domain of Spoonbill depletes pathogenic non-coding spinocerebellar ataxia 8 transcripts and suppresses neurodegeneration in Drosophila. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1732-41. [PMID: 27302466 DOI: 10.1016/j.bbadis.2016.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 06/06/2016] [Accepted: 06/09/2016] [Indexed: 12/26/2022]
Abstract
Spinocerebellar ataxia 8 (SCA8) pathogenesis is a resultant of gain-of-function machinery that primarily results at the RNA level. It has been reported that expanded non-coding CTG trinucleotide repeat in the ATXN8OS transcripts leads to SCA8 coupled neurodegeneration. Targeted depletion of pathogenic SCA8 transcripts is a viable therapeutic approach. In this report we have focused on the suppression of toxic RNA gain-of-function associated with SCA8. We report suppression of SCA8 associated neurodegeneration by KH RNA binding domain of Spoonbill. KH domain suppresses pathogenic SCA8 associated phenotype in adult flies. Ectopic expression of KH domain leads to massive reduction in the number and size of SCA8 RNA foci. We show that Spoonbill interacts with toxic SCA8 transcripts via its KH domain and promotes its depletion. Till date, no attempts have been made for therapeutic intervention of SCA8 pathogenesis. Further characterization of Spoonbill KH domain may aid us in designing peptide based therapeutics for SCA8 associated neurodegeneration.
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Affiliation(s)
- Bipin K Tripathi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Satya Surabhi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Pradeep K Bhaskar
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India.
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108
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Krench M, Cho RW, Littleton JT. A Drosophila model of Huntington disease-like 2 exhibits nuclear toxicity and distinct pathogenic mechanisms from Huntington disease. Hum Mol Genet 2016; 25:3164-3177. [PMID: 27288455 DOI: 10.1093/hmg/ddw166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/22/2016] [Accepted: 05/20/2016] [Indexed: 12/23/2022] Open
Abstract
Huntington disease-like 2 (HDL2) and Huntington disease (HD) are adult-onset neurodegenerative diseases characterized by movement disorders, psychiatric disturbances and cognitive decline. Brain tissue from HD and HDL2 patients shows degeneration of the striatum and ubiquitinated inclusions immunoreactive for polyglutamine (polyQ) antibodies. Despite these similarities, the diseases result from different genetic mutations. HD is caused by a CAG repeat expansion in the huntingtin (HTT) gene, while HDL2 results from an expansion at the junctophilin 3 (JPH3) locus. Recent evidence indicates that the HDL2 expansion may give rise to a toxic polyQ protein translated from an antisense mRNA derived from the JPH3 locus. To investigate this hypothesis, we generated and characterized a Drosophila HDL2 model and compared it with a previously established HD model. We find that neuronal expression of HDL2-Q15 is not toxic, while the expression of an expanded HDL2-Q138 protein is lethal. HDL2-Q138 forms large nuclear aggregates, with only smaller puncta observed in the cytoplasm. This is in contrast to what is observed in a Drosophila model of HD, where polyQ aggregates localize exclusively to the cytoplasm. Altering localization of HLD2 with the addition of a nuclear localization or nuclear export sequence demonstrates that nuclear accumulation is required for toxicity in the Drosophila HDL2 model. Directing HDL2-Q138 to the nucleus exacerbates toxicity in multiple tissue types, while confining HDL2-Q138 to the cytoplasm restores viability to control levels. We conclude that while HD and HDL2 have similar clinical profiles, distinct pathogenic mechanisms are likely to drive toxicity in Drosophila models of these disorders.
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Affiliation(s)
- Megan Krench
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences
| | - Richard W Cho
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences .,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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109
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Shukla S, Parker R. Hypo- and Hyper-Assembly Diseases of RNA-Protein Complexes. Trends Mol Med 2016; 22:615-628. [PMID: 27263464 DOI: 10.1016/j.molmed.2016.05.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 12/14/2022]
Abstract
A key aspect of cellular function is the proper assembly and utilization of ribonucleoproteins (RNPs). Recent studies have shown that hyper- or hypo-assembly of various RNPs can lead to human diseases. Defects in the formation of RNPs lead to 'RNP hypo-assembly diseases', which can be caused by RNA degradation outcompeting RNP assembly. By contrast, excess RNP assembly, either in higher order RNP granules, or due to the expression of repeat-containing RNAs, can lead to 'RNP hyper-assembly diseases'. Here, we discuss the most recent advances in understanding the cause of disease onset, as well as potential therapies from the aspect of modulating RNP assembly in the cell, which presents a novel route to the treatment of these diseases.
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Affiliation(s)
- Siddharth Shukla
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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110
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Cocito C, Merighi A, Giacobini M, Lossi L. Alterations of Cell Proliferation and Apoptosis in the Hypoplastic Reeler Cerebellum. Front Cell Neurosci 2016; 10:141. [PMID: 27252624 PMCID: PMC4879145 DOI: 10.3389/fncel.2016.00141] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/10/2016] [Indexed: 12/24/2022] Open
Abstract
A mutation of the reln gene gives rise to the Reeler mouse (reln−∕−) displaying an ataxic phenotype and cerebellar hypoplasia. We have characterized the neurochemistry of postnatal (P0–P60) reln−∕− mouse cerebella with specific attention to the intervention of cell proliferation and apoptosis in the P0–P25 interval. Homozygous reln−∕− mice and age-matched controls were analyzed by immunofluorescence using primary antibodies against NeuN, calbindin, GFAP, vimentin, SMI32, and GAD67. Proliferation and apoptosis were detected after a single intraperitoneal BrdU injection and by the TUNEL assay with anti-digoxigenin rhodamine-conjugated antibodies. Quantitative analysis with descriptive and predictive statistics was used to calculate cell densities (number/mm2) after fluorescent nuclear stain (TCD, total cell density), labeling with BrdU (PrCD, proliferating cell density), or TUNEL (ApoCD, apoptotic cell density). By this approach we first have shown that the temporal pattern of expression of neuronal/glial markers in postnatal cerebellum is not affected by the Reeler mutation. Then, we have demonstrated that the hypoplasia in the Reeler mouse cerebellum is consequent to reduction of cortical size and cellularity (TCD), and that TCD is, in turn, linked to quantitative differences in the extent of cell proliferation and apoptosis, as well as derangements in their temporal trends during postnatal maturation. Finally, we have calculated that PrCD is the most important predictive factor to determine TCD in the cerebellar cortex of the mutants. These results support the notion that, beside the well-known consequences onto the migration of the cerebellar neurons, the lack of Reelin results in a measurable deficit in neural proliferation.
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Affiliation(s)
- Carolina Cocito
- Laboratory of Neuroscience, Department of Veterinary Sciences, University of Turin Grugliasco, Italy
| | - Adalberto Merighi
- Laboratory of Neuroscience, Department of Veterinary Sciences, University of Turin Grugliasco, Italy
| | - Mario Giacobini
- Laboratory of Dynamical Systems and Epidemiology, Department of Veterinary Sciences, University of Turin Grugliasco, Italy
| | - Laura Lossi
- Laboratory of Neuroscience, Department of Veterinary Sciences, University of Turin Grugliasco, Italy
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111
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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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112
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Chatterjee N, Lin Y, Wilson JH. Mismatch repair enhances convergent transcription-induced cell death at trinucleotide repeats by activating ATR. DNA Repair (Amst) 2016; 42:26-32. [PMID: 27131875 DOI: 10.1016/j.dnarep.2016.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 01/08/2023]
Abstract
Trinucleotide repeat (TNR) expansion beyond a certain threshold results in some 20 incurable neurodegenerative disorders where disease anticipation positively correlates with repeat length. Long TNRs typically display a bias toward further expansion during germinal transmission from parents to offspring, and then are highly unstable in somatic tissues of affected individuals. Understanding mechanisms of TNR instability will provide insights into disease pathogenesis. Previously, we showed that enhanced convergent transcription at long CAG repeat tracks induces TNR instability and cell death via ATR activation. Components of TC-NER (transcription-coupled nucleotide excision repair) and RNaseH enzymes that resolve RNA/DNA hybrids oppose cell death, whereas the MSH2 component of MMR (mismatch repair) enhances cell death. The exact role of the MMR pathway during convergent transcription-induced cell death at CAG repeats is not well understood. In this study, we show that siRNA knockdowns of MMR components-MSH2, MSH3, MLHI, PMS2, and PCNA-reduce DNA toxicity. Furthermore, knockdown of MSH2, MLH1, and PMS2 significantly reduces the frequency of ATR foci formation. These observations suggest that MMR proteins activate DNA toxicity by modulating ATR foci formation during convergent transcription.
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Affiliation(s)
- Nimrat Chatterjee
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Yunfu Lin
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA
| | - John H Wilson
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
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113
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Bushart DD, Murphy GG, Shakkottai VG. Precision medicine in spinocerebellar ataxias: treatment based on common mechanisms of disease. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:25. [PMID: 26889478 DOI: 10.3978/j.issn.2305-5839.2016.01.06] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Spinocerebellar ataxias (SCAs) are a heterogeneous group of dominantly inherited neurodegenerative disorders affecting the cerebellum and its associated pathways. There are no available symptomatic or disease-modifying therapies available for any of the over 30 known causes of SCA. In order to develop precise treatments for SCAs, two strategies can be employed: (I) the use of gene-targeting strategies to silence disease-causing mutant protein expression; and (II) the identification and targeting of convergent mechanisms of disease across SCAs as a basis for treatment. Gene targeting strategies include RNA interference and antisense oligonucleotides designed to silence mutant genes in order to prevent mutant protein expression. These therapies can be precise, but delivery is difficult and many disease-causing mutations remain unknown. Emerging evidence suggests that several common disease mechanisms may exist across SCAs. Disrupted protein homeostasis, RNA toxicity, abnormal synaptic signaling, altered intracellular calcium handling, and altered Purkinje neuron membrane excitability are all disease mechanisms which are seen in multiple etiologies of SCA and could potentially be targeted for treatment. Clinical trials with drugs such as riluzole, a potassium channel activator, show promise for multiple SCAs and suggest that convergent disease mechanisms do exist and can be targeted. Precise treatment of SCAs may be best achieved through pharmacologic agents targeting specific disrupted pathways.
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Affiliation(s)
- David D Bushart
- 1 Department of Molecular & Integrative Physiology, 2 Molecular & Behavioral Neuroscience Institute, 3 Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Geoffrey G Murphy
- 1 Department of Molecular & Integrative Physiology, 2 Molecular & Behavioral Neuroscience Institute, 3 Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vikram G Shakkottai
- 1 Department of Molecular & Integrative Physiology, 2 Molecular & Behavioral Neuroscience Institute, 3 Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
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114
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Wu R, Su Y, Wu H, Dai Y, Zhao M, Lu Q. Characters, functions and clinical perspectives of long non-coding RNAs. Mol Genet Genomics 2016; 291:1013-33. [PMID: 26885843 DOI: 10.1007/s00438-016-1179-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 01/26/2016] [Indexed: 02/07/2023]
Abstract
It is well established that most of the human genome and those of other mammals and plants are transcribed into RNA without protein-coding capacity, which we define as non-coding RNA. From siRNA to microRNA, whose functions and features have been well characterized, non-coding RNAs have been a popular topic in life science research over the last decade. Long non-coding RNAs (lncRNAs), however, as a novel class of transcripts, are distinguished from these other small RNAs. Recent studies have revealed a diverse population of lncRNAs with different sizes and functions across different species. These populations are expressed dynamically and act as important regulators in a variety of biological processes, especially in gene expression. Nevertheless, the functions and mechanisms of most lncRNAs remain unclear. In this review, we present recent progress in the identification of lncRNAs, their functions and molecular mechanisms, their roles in human diseases, their potential diagnostic and therapeutic applications as well as newer technologies for identifying deregulated lncRNAs in disease tissues.
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Affiliation(s)
- Ruifang Wu
- Hunan Key Laboratory of Medical Epigenomics, Department of Dermatology, The Second Xiangya Hospital, Central South University, #139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Yuwen Su
- Hunan Key Laboratory of Medical Epigenomics, Department of Dermatology, The Second Xiangya Hospital, Central South University, #139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Haijing Wu
- Hunan Key Laboratory of Medical Epigenomics, Department of Dermatology, The Second Xiangya Hospital, Central South University, #139 Renmin Middle Road, Changsha, 410011, Hunan, China
| | - Yong Dai
- Clinical Medical Research Center, The Second Clinical Medical College of Jinan University (Shenzhen People's Hospital), Shenzhen, 518020, Guangdong, China
| | - Ming Zhao
- Hunan Key Laboratory of Medical Epigenomics, Department of Dermatology, The Second Xiangya Hospital, Central South University, #139 Renmin Middle Road, Changsha, 410011, Hunan, China.
| | - Qianjin Lu
- Hunan Key Laboratory of Medical Epigenomics, Department of Dermatology, The Second Xiangya Hospital, Central South University, #139 Renmin Middle Road, Changsha, 410011, Hunan, China.
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Arimoto-Matsuzaki K, Saito H, Takekawa M. TIA1 oxidation inhibits stress granule assembly and sensitizes cells to stress-induced apoptosis. Nat Commun 2016; 7:10252. [PMID: 26738979 PMCID: PMC4729832 DOI: 10.1038/ncomms10252] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/20/2015] [Indexed: 12/24/2022] Open
Abstract
Cytoplasmic stress granules (SGs) are multimolecular aggregates of stalled translation pre-initiation complexes that prevent the accumulation of misfolded proteins, and that are formed in response to certain types of stress including ER stress. SG formation contributes to cell survival not only by suppressing translation but also by sequestering some apoptosis regulatory factors. Because cells can be exposed to various stresses simultaneously in vivo, the regulation of SG assembly under multiple stress conditions is important but unknown. Here we report that reactive oxygen species (ROS) such as H2O2 oxidize the SG-nucleating protein TIA1, thereby inhibiting SG assembly. Thus, when cells are confronted with a SG-inducing stress such as ER stress caused by protein misfolding, together with ROS-induced oxidative stress, they cannot form SGs, resulting in the promotion of apoptosis. We demonstrate that the suppression of SG formation by oxidative stress may underlie the neuronal cell death seen in neurodegenerative diseases. Cytoplasmic stress granules (SG) are intracellular aggregates that suppress translation and sequester apoptosis regulatory factors. Here the authors show that reactive oxygen species oxidise the SG-nucleating protein TIA1, preventing SG formation and promoting apoptosis in the presence of additional stress.
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Affiliation(s)
- Kyoko Arimoto-Matsuzaki
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Haruo Saito
- Division of Molecular Cell Signaling, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Mutsuhiro Takekawa
- Division of Cell Signaling and Molecular Medicine, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
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Loureiro JR, Oliveira CL, Silveira I. Unstable repeat expansions in neurodegenerative diseases: nucleocytoplasmic transport emerges on the scene. Neurobiol Aging 2015; 39:174-83. [PMID: 26923414 DOI: 10.1016/j.neurobiolaging.2015.12.007] [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: 10/19/2015] [Revised: 12/07/2015] [Accepted: 12/15/2015] [Indexed: 12/12/2022]
Abstract
An astonishing number of neurological diseases result from expansion of unstable repetitive sequences causing alterations in key neuronal processes. Some are progressive late-onset conditions related to aging, such as the spinocerebellar ataxias. In several of these pathologies, the expanded repeat is transcribed, producing an expanded RNA repeat that causes neurodegeneration by a complex mechanism, comprising 3 main pathways. These include (1) accumulation in the nucleus of RNA foci, resulting from sequestration of RNA-binding proteins functioning in important neuronal cascades; (2) decrease in availability of RNA-binding proteins, such as splicing factors, causing alternative splicing misregulation with imbalance in the expression ratio of neuronal isoforms; and (3) generation of neurotoxic peptides, produced from repeat-associated non-ATG-initiated translation across the RNA repeat, in all reading frames. Recently, 2 pathologies characterized by impaired motor function, cognitive decline, or/and degeneration of motor neurons have been found that have broaden our understanding of these diseases. Moreover, the finding of compromised nucleocytoplasmic transport opens new avenues for research. This review will cover the amazing progress regarding these conditions.
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Affiliation(s)
- Joana R Loureiro
- Group Genetics of Cognitive Dysfunction, i3s- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal; ICBAS, Universidade do Porto, Portugal
| | - Claudia L Oliveira
- Group Genetics of Cognitive Dysfunction, i3s- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal; ICBAS, Universidade do Porto, Portugal
| | - Isabel Silveira
- Group Genetics of Cognitive Dysfunction, i3s- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal; ICBAS, Universidade do Porto, Portugal.
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Nguyen L, Luu LM, Peng S, Serrano JF, Chan HYE, Zimmerman SC. Rationally designed small molecules that target both the DNA and RNA causing myotonic dystrophy type 1. J Am Chem Soc 2015; 137:14180-9. [PMID: 26473464 DOI: 10.1021/jacs.5b09266] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Single-agent, single-target therapeutic approaches are often limited by a complex disease pathobiology. We report rationally designed, multi-target agents for myotonic dystrophy type 1 (DM1). DM1 originates in an abnormal expansion of CTG repeats (CTG(exp)) in the DMPK gene. The resultant expanded CUG transcript (CUG(exp)) identified as a toxic agent sequesters important proteins, such as muscleblind-like proteins (MBNL), undergoes repeat-associated non-ATG (RAN) translation, and potentially causes microRNA dysregulation. We report rationally designed small molecules that target the DM1 pathobiology in vitro in three distinct ways by acting simultaneously as transcription inhibitors, by inhibiting aberrant protein binding to the toxic RNA, and by acting as RNase mimics to degrade the toxic RNA. In vitro, the agents are shown to (1) bind CTG(exp) and inhibit formation of the CUG(exp) transcript, (2) bind CUG(exp) and inhibit sequestration of MBNL1, and (3) cleave CUG(exp) in an RNase-like manner. The most potent compounds are capable of reducing the levels of CUG(exp) in DM1 model cells, and one reverses two separate CUG(exp)-induced phenotypes in a DM1 Drosophila model.
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Affiliation(s)
- Lien Nguyen
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Long M Luu
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Shaohong Peng
- Laboratory of Drosophila Research and School of Life Sciences, The Chinese University of Hong Kong , Shatin N.T., Hong Kong, SAR
| | - Julio F Serrano
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - H Y Edwin Chan
- Laboratory of Drosophila Research and School of Life Sciences, The Chinese University of Hong Kong , Shatin N.T., Hong Kong, SAR
| | - Steven C Zimmerman
- Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
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Chakraborty M, Selma-Soriano E, Magny E, Couso JP, Pérez-Alonso M, Charlet-Berguerand N, Artero R, Llamusi B. Pentamidine rescues contractility and rhythmicity in a Drosophila model of myotonic dystrophy heart dysfunction. Dis Model Mech 2015; 8:1569-78. [PMID: 26515653 PMCID: PMC4728315 DOI: 10.1242/dmm.021428] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 10/19/2015] [Indexed: 02/01/2023] Open
Abstract
Up to 80% of individuals with myotonic dystrophy type 1 (DM1) will develop cardiac abnormalities at some point during the progression of their disease, the most common of which is heart blockage of varying degrees. Such blockage is characterized by conduction defects and supraventricular and ventricular tachycardia, and carries a high risk of sudden cardiac death. Despite its importance, very few animal model studies have focused on the heart dysfunction in DM1. Here, we describe the characterization of the heart phenotype in a Drosophila model expressing pure expanded CUG repeats under the control of the cardiomyocyte-specific driver GMH5-Gal4. Morphologically, expression of 250 CUG repeats caused abnormalities in the parallel alignment of the spiral myofibrils in dissected fly hearts, as revealed by phalloidin staining. Moreover, combined immunofluorescence and in situ hybridization of Muscleblind and CUG repeats, respectively, confirmed detectable ribonuclear foci and Muscleblind sequestration, characteristic features of DM1, exclusively in flies expressing the expanded CTG repeats. Similarly to what has been reported in humans with DM1, heart-specific expression of toxic RNA resulted in reduced survival, increased arrhythmia, altered diastolic and systolic function, reduced heart tube diameters and reduced contractility in the model flies. As a proof of concept that the fly heart model can be used for in vivo testing of promising therapeutic compounds, we fed flies with pentamidine, a compound previously described to improve DM1 phenotypes. Pentamidine not only released Muscleblind from the CUG RNA repeats and reduced ribonuclear formation in the Drosophila heart, but also rescued heart arrhythmicity and contractility, and improved fly survival in animals expressing 250 CUG repeats.
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Affiliation(s)
- Mouli Chakraborty
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Estela Selma-Soriano
- Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Emile Magny
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Juan Pablo Couso
- School of Life Sciences, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK
| | - Manuel Pérez-Alonso
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Nicolas Charlet-Berguerand
- Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 1 Rue Laurent Fries, 67400 Illkirch-Graffenstaden, France
| | - Ruben Artero
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
| | - Beatriz Llamusi
- Translational Genomics Group, Incliva Health Research Institute, Avda. Menendez Pelayo 4 acc 46010, Valencia, Spain Department of Genetics and Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universitat de València, Dr Moliner 50, Burjasot 46100, Spain
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Choubtum L, Witoonpanich P, Hanchaiphiboolkul S, Bhidayasiri R, Jitkritsadakul O, Pongpakdee S, Wetchaphanphesat S, Boonkongchuen P, Pulkes T. Analysis of SCA8, SCA10, SCA12, SCA17 and SCA19 in patients with unknown spinocerebellar ataxia: a Thai multicentre study. BMC Neurol 2015; 15:166. [PMID: 26374734 PMCID: PMC4571065 DOI: 10.1186/s12883-015-0425-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/08/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND About 50 % of Thai patients with adult-onset spinocerebellar ataxia (SCA) was Machado-Joseph disease (MJD), SCA1, SCA2 and SCA6. The author investigated further on less common SCAs in the patients without any known mutations. METHODS DNA samples of 82 index patients who were genetically excluded MJD, SCA1, SCA2, SCA6, SCA7 and dentatorubro-pallidoluysian atrophy (DRPLA) were examined. Analysis of SCA8, SCA10, SCA12, SCA17 and SCA19 genes were comprehensively performed. Normal range of trinucleotide repeat expansion sizes of TATA-box-binding protein gene (TBP) were also determined in 374 control subjects. RESULTS Eight patients carried ≥42 CAG/CAA repeat allele in the TBP consistent with SCA17. The pathological repeat alleles ranged from 42 to 57 repeats. All patients had significant degree of cognitive dysfunction. Other non-ataxic phenotypes comprised of parkinsonism, chorea, dystonia and myoclonus. A sporadic patient carried a heterozygous 41-repeat allele developed chronic progressive cerebellar degeneration commenced at the age of 28 years. Whilst, 2 % of the control subjects (8/374) carried the 41-repeat allele. Five of the carriers were re-examined, and revealed that four of them had parkinsonism and/or cognitive impairment without cerebellar signs. Analysis of other types of SCAs was all negative. CONCLUSIONS This is the first study of SCA8, SCA10, SCA12, SCA17 and SCA19 in Thais. SCA17 appears to be an important cause of ataxia in Thailand. Although, the pathological cut-off point of the TBP repeat allele remains unclear, the finding suggests that the 41-repeat may be a pathological allele resulting late-onset or mild phenotype. Apart from ataxia, cognitive impairment and parkinsonism may be clinical presentations in these carriers.
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Affiliation(s)
- Lulin Choubtum
- Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. .,Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
| | - Pirada Witoonpanich
- Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
| | | | - Roongroj Bhidayasiri
- Chulalongkorn Center of Excellence on Parkinson Disease and Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, 10330, Thailand.
| | - Onanong Jitkritsadakul
- Chulalongkorn Center of Excellence on Parkinson Disease and Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, 10330, Thailand.
| | | | | | - Pairoj Boonkongchuen
- Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
| | - Teeratorn Pulkes
- Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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120
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A pathophysiological view of the long non-coding RNA world. Oncotarget 2015; 5:10976-96. [PMID: 25428918 PMCID: PMC4294373 DOI: 10.18632/oncotarget.2770] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/14/2014] [Indexed: 12/13/2022] Open
Abstract
Because cells are constantly exposed to micro-environmental changes, they require the ability to adapt to maintain a dynamic equilibrium. Proteins are considered critical for the regulation of gene expression, which is a fundamental process in determining the cellular responses to stimuli. Recently, revolutionary findings in RNA research and the advent of high-throughput genomic technologies have revealed a pervasive transcription of the human genome, which generates many long non-coding RNAs (lncRNAs) whose roles are largely undefined. However, there is evidence that lncRNAs are involved in several cellular physiological processes such as adaptation to stresses, cell differentiation, maintenance of pluripotency and apoptosis. The correct balance of lncRNA levels is crucial for the maintenance of cellular equilibrium, and the dysregulation of lncRNA expression is linked to many disorders; certain transcripts are useful prognostic markers for some of these pathologies. This review revisits the classic concept of cellular homeostasis from the perspective of lncRNAs specifically to understand how this novel class of molecules contributes to cellular balance and how its dysregulated expression can lead to the onset of pathologies such as cancer.
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Sun X, Li PP, Zhu S, Cohen R, Marque LO, Ross CA, Pulst SM, Chan HYE, Margolis RL, Rudnicki DD. Nuclear retention of full-length HTT RNA is mediated by splicing factors MBNL1 and U2AF65. Sci Rep 2015. [PMID: 26218986 PMCID: PMC4517393 DOI: 10.1038/srep12521] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion in the huntingtin (HTT) gene. Recent evidence suggests that HD is a consequence of multimodal, non-mutually exclusive mechanisms of pathogenesis that involve both HTT protein- and HTT RNA-triggered mechanisms. Here we provide further evidence for the role of expanded HTT (expHTT) RNA in HD by demonstrating that a fragment of expHTT is cytotoxic in the absence of any translation and that the extent of cytotoxicity is similar to the cytotoxicity of an expHTT protein fragment encoded by a transcript of similar length and with a similar repeat size. In addition, full-length (FL) expHTT is retained in the nucleus. Overexpression of the splicing factor muscleblind-like 1 (MBNL1) increases nuclear retention of expHTT and decreases the expression of expHTT protein in the cytosol. The splicing and nuclear export factor U2AF65 has the opposite effect, decreasing expHTT nuclear retention and increasing expression of expHTT protein. This suggests that MBNL1 and U2AF65 play a role in nuclear export of expHTT RNA.
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Affiliation(s)
- Xin Sun
- 1] Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [2] Guangdong-Hong Kong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong, China
| | - Pan P Li
- Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shanshan Zhu
- Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rachael Cohen
- Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Leonard O Marque
- Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christopher A Ross
- 1] Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [2] Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [3] Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [4] Program of Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Ho Yin Edwin Chan
- Laboratory of Drosophila Research, School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Russell L Margolis
- 1] Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [2] Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [3] Program of Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Dobrila D Rudnicki
- 1] Department of Psychiatry and Behavioral Sciences, Division of Neurobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA [2] Program of Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Kim JS, Cho JW. Hereditary Cerebellar Ataxias: A Korean Perspective. J Mov Disord 2015; 8:67-75. [PMID: 26090078 PMCID: PMC4460542 DOI: 10.14802/jmd.15006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 12/28/2022] Open
Abstract
Hereditary ataxia is a heterogeneous disorder characterized by progressive ataxia combined with/without peripheral neuropathy, extrapyramidal symptoms, pyramidal symptoms, seizure, and multiple systematic involvements. More than 35 autosomal dominant cerebellar ataxias have been designated as spinocerebellar ataxia, and there are 55 recessive ataxias that have not been named systematically. Conducting genetic sequencing to confirm a diagnosis is difficult due to the large amount of subtypes with phenotypic overlap. The prevalence of hereditary ataxia can vary among countries, and estimations of prevalence and subtype frequencies are necessary for planning a diagnostic strategy in a specific population. This review covers the various hereditary ataxias reported in the Korean population with a focus on the prevalence and subtype frequencies as the clinical characteristics of the various subtypes.
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Affiliation(s)
- Ji Sun Kim
- Department of Neurology, Soonchunhyang University Hospital, Soonchunhyang University School of Medicine, Seoul, Korea
| | - Jin Whan Cho
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea ; Neuroscience Center, Samsung Medical Center, Seoul, Korea
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123
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Abstract
Approximately 40 human diseases are associated with expansion of repeat sequences. These expansions can reside within coding or non-coding parts of the genes, affecting the host gene function. The presence of such expansions results in the production of toxic RNA and/or protein or causes transcriptional repression and silencing of the host gene. Although the molecular mechanisms of expansion diseases are not well understood, mounting evidence suggests that transcription through expanded repeats plays an essential role in disease pathology. The presence of an expansion can affect RNA polymerase transcription, leading to dysregulation of transcription-associated processes, such as RNA splicing, formation of RNA/DNA hybrids (R-loops), production of antisense, short non-coding and bidirectional RNA transcripts. In the present review, we summarize current advances in this field and discuss possible roles of transcriptional defects in disease pathology.
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Dansithong W, Paul S, Figueroa KP, Rinehart MD, Wiest S, Pflieger LT, Scoles DR, Pulst SM. Ataxin-2 regulates RGS8 translation in a new BAC-SCA2 transgenic mouse model. PLoS Genet 2015; 11:e1005182. [PMID: 25902068 PMCID: PMC4406435 DOI: 10.1371/journal.pgen.1005182] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 03/28/2015] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant disorder with progressive degeneration of cerebellar Purkinje cells (PCs) and other neurons caused by expansion of a glutamine (Q) tract in the ATXN2 protein. We generated BAC transgenic lines in which the full-length human ATXN2 gene was transcribed using its endogenous regulatory machinery. Mice with the ATXN2 BAC transgene with an expanded CAG repeat (BAC-Q72) developed a progressive cellular and motor phenotype, whereas BAC mice expressing wild-type human ATXN2 (BAC-Q22) were indistinguishable from control mice. Expression analysis of laser-capture microdissected (LCM) fractions and regional expression confirmed that the BAC transgene was expressed in PCs and in other neuronal groups such as granule cells (GCs) and neurons in deep cerebellar nuclei as well as in spinal cord. Transcriptome analysis by deep RNA-sequencing revealed that BAC-Q72 mice had progressive changes in steady-state levels of specific mRNAs including Rgs8, one of the earliest down-regulated transcripts in the Pcp2-ATXN2[Q127] mouse line. Consistent with LCM analysis, transcriptome changes analyzed by deep RNA-sequencing were not restricted to PCs, but were also seen in transcripts enriched in GCs such as Neurod1. BAC-Q72, but not BAC-Q22 mice had reduced Rgs8 mRNA levels and even more severely reduced steady-state protein levels. Using RNA immunoprecipitation we showed that ATXN2 interacted selectively with RGS8 mRNA. This interaction was impaired when ATXN2 harbored an expanded polyglutamine. Mutant ATXN2 also reduced RGS8 expression in an in vitro coupled translation assay when compared with equal expression of wild-type ATXN2-Q22. Reduced abundance of Rgs8 in Pcp2-ATXN2[Q127] and BAC-Q72 mice supports our observations of a hyper-excitable mGluR1-ITPR1 signaling axis in SCA2, as RGS proteins are linked to attenuating mGluR1 signaling.
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Affiliation(s)
- Warunee Dansithong
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Karla P. Figueroa
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Marc D. Rinehart
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Shaina Wiest
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Lance T. Pflieger
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Daniel R. Scoles
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
| | - Stefan M. Pulst
- Department of Neurology, University of Utah, Salt Lake City, Utah, United States of America
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Parkinsonism in spinocerebellar ataxia. BIOMED RESEARCH INTERNATIONAL 2015; 2015:125273. [PMID: 25866756 PMCID: PMC4383270 DOI: 10.1155/2015/125273] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/29/2014] [Accepted: 10/13/2014] [Indexed: 11/17/2022]
Abstract
Spinocerebellar ataxia (SCA) presents heterogeneous clinical phenotypes, and parkinsonism is reported in diverse SCA subtypes. Both levodopa responsive Parkinson disease (PD) like phenotype and atypical parkinsonism have been described especially in SCA2, SCA3, and SCA17 with geographic differences in prevalence. SCA2 is the most frequently reported subtype of SCA related to parkinsonism worldwide. Parkinsonism in SCA2 has unique genetic characteristics, such as low number of expansions and interrupted structures, which may explain the sporadic cases with low penetrance. Parkinsonism in SCA17 is more remarkable in Asian populations especially in Korea. In addition, an unclear cutoff of the pathologic range is the key issue in SCA17 related parkinsonism. SCA3 is more common in western cohorts. SCA6 and SCA8 have also been reported with a PD-like phenotype. Herein, we reviewed the epidemiologic, clinical, genetic, and pathologic features of parkinsonism in SCAs.
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126
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Exploring the secrets of long noncoding RNAs. Int J Mol Sci 2015; 16:5467-96. [PMID: 25764159 PMCID: PMC4394487 DOI: 10.3390/ijms16035467] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/22/2015] [Accepted: 03/03/2015] [Indexed: 12/14/2022] Open
Abstract
High-throughput sequencing has revealed that the majority of RNAs have no capacity to encode protein. Among these non-coding transcripts, recent work has focused on the roles of long noncoding RNAs (lncRNAs) of >200 nucleotides. Although many of their attributes, such as patterns of expression, remain largely unknown, lncRNAs have key functions in transcriptional, post-transcriptional, and epigenetic gene regulation; Also, new work indicates their functions in scaffolding ribonuclear protein complexes. In plants, genome-wide identification of lncRNAs has been conducted in several species, including Zea mays, and recent research showed that lncRNAs regulate flowering time in the photoperiod pathway, and function in nodulation. In this review, we discuss the basic mechanisms by which lncRNAs regulate key cellular processes, using the large body of knowledge on animal and yeast lncRNAs to illustrate the significance of emerging work on lncRNAs in plants.
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Walsh MJ, Cooper-Knock J, Dodd JE, Stopford MJ, Mihaylov SR, Kirby J, Shaw PJ, Hautbergue GM. Invited review: decoding the pathophysiological mechanisms that underlie RNA dysregulation in neurodegenerative disorders: a review of the current state of the art. Neuropathol Appl Neurobiol 2015; 41:109-34. [PMID: 25319671 PMCID: PMC4329338 DOI: 10.1111/nan.12187] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/07/2014] [Indexed: 12/12/2022]
Abstract
Altered RNA metabolism is a key pathophysiological component causing several neurodegenerative diseases. Genetic mutations causing neurodegeneration occur in coding and noncoding regions of seemingly unrelated genes whose products do not always contribute to the gene expression process. Several pathogenic mechanisms may coexist within a single neuronal cell, including RNA/protein toxic gain-of-function and/or protein loss-of-function. Genetic mutations that cause neurodegenerative disorders disrupt healthy gene expression at diverse levels, from chromatin remodelling, transcription, splicing, through to axonal transport and repeat-associated non-ATG (RAN) translation. We address neurodegeneration in repeat expansion disorders [Huntington's disease, spinocerebellar ataxias, C9ORF72-related amyotrophic lateral sclerosis (ALS)] and in diseases caused by deletions or point mutations (spinal muscular atrophy, most subtypes of familial ALS). Some neurodegenerative disorders exhibit broad dysregulation of gene expression with the synthesis of hundreds to thousands of abnormal messenger RNA (mRNA) molecules. However, the number and identity of aberrant mRNAs that are translated into proteins - and how these lead to neurodegeneration - remain unknown. The field of RNA biology research faces the challenge of identifying pathophysiological events of dysregulated gene expression. In conclusion, we discuss current research limitations and future directions to improve our characterization of pathological mechanisms that trigger disease onset and progression.
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Affiliation(s)
- M J Walsh
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J Cooper-Knock
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J E Dodd
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - M J Stopford
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - S R Mihaylov
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - J Kirby
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - P J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
| | - G M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of SheffieldSheffield, UK
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128
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Sun M, Kraus WL. From discovery to function: the expanding roles of long noncoding RNAs in physiology and disease. Endocr Rev 2015; 36:25-64. [PMID: 25426780 PMCID: PMC4309736 DOI: 10.1210/er.2014-1034] [Citation(s) in RCA: 311] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Long noncoding RNAs (lncRNAs) are a relatively poorly understood class of RNAs with little or no coding capacity transcribed from a set of incompletely annotated genes. They have received considerable attention in the past few years and are emerging as potentially important players in biological regulation. Here we discuss the evolving understanding of this new class of molecular regulators that has emerged from ongoing research, which continues to expand our databases of annotated lncRNAs and provide new insights into their physical properties, molecular mechanisms of action, and biological functions. We outline the current strategies and approaches that have been employed to identify and characterize lncRNAs, which have been instrumental in revealing their multifaceted roles ranging from cis- to trans-regulation of gene expression and from epigenetic modulation in the nucleus to posttranscriptional control in the cytoplasm. In addition, we highlight the molecular and biological functions of some of the best characterized lncRNAs in physiology and disease, especially those relevant to endocrinology, reproduction, metabolism, immunology, neurobiology, muscle biology, and cancer. Finally, we discuss the tremendous diagnostic and therapeutic potential of lncRNAs in cancer and other diseases.
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Affiliation(s)
- Miao Sun
- Laboratory of Signaling and Gene Regulation, Cecil H. and Ida Green Center for Reproductive Biology Sciences and Division of Basic Reproductive Biology Research, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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129
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Usdin K, House NCM, Freudenreich CH. Repeat instability during DNA repair: Insights from model systems. Crit Rev Biochem Mol Biol 2015; 50:142-67. [PMID: 25608779 DOI: 10.3109/10409238.2014.999192] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The expansion of repeated sequences is the cause of over 30 inherited genetic diseases, including Huntington disease, myotonic dystrophy (types 1 and 2), fragile X syndrome, many spinocerebellar ataxias, and some cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Repeat expansions are dynamic, and disease inheritance and progression are influenced by the size and the rate of expansion. Thus, an understanding of the various cellular mechanisms that cooperate to control or promote repeat expansions is of interest to human health. In addition, the study of repeat expansion and contraction mechanisms has provided insight into how repair pathways operate in the context of structure-forming DNA, as well as insights into non-canonical roles for repair proteins. Here we review the mechanisms of repeat instability, with a special emphasis on the knowledge gained from the various model systems that have been developed to study this topic. We cover the repair pathways and proteins that operate to maintain genome stability, or in some cases cause instability, and the cross-talk and interactions between them.
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Affiliation(s)
- Karen Usdin
- Laboratory of Cell and Molecular Biology, NIDDK, NIH , Bethesda, MD , USA
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130
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Brown SA, Loew LM. Integration of modeling with experimental and clinical findings synthesizes and refines the central role of inositol 1,4,5-trisphosphate receptor 1 in spinocerebellar ataxia. Front Neurosci 2015; 8:453. [PMID: 25653583 PMCID: PMC4300941 DOI: 10.3389/fnins.2014.00453] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/22/2014] [Indexed: 12/22/2022] Open
Abstract
A suite of models was developed to study the role of inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in spinocerebellar ataxias (SCAs). Several SCAs are linked to reduced abundance of IP3R1 or to supranormal sensitivity of the receptor to activation by its ligand inositol 1,4,5-trisphosphate (IP3). Detailed multidimensional models have been created to simulate biochemical calcium signaling and membrane electrophysiology in cerebellar Purkinje neurons. In these models, IP3R1-mediated calcium release is allowed to interact with ion channel response on the cell membrane. Experimental findings in mice and clinical observations in humans provide data input for the models. The SCA modeling suite helps interpret experimental results and provides suggestions to guide experiments. The models predict IP3R1 supersensitivity in SCA1 and compensatory mechanisms in SCA1, SCA2, and SCA3. Simulations explain the impact of calcium buffer proteins. Results show that IP3R1-mediated calcium release activates voltage-gated calcium-activated potassium channels in the plasma membrane. The SCA modeling suite unifies observations from experiments in a number of SCAs. The cadre of simulations demonstrates the central role of IP3R1.
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Affiliation(s)
| | - Leslie M Loew
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center Farmington, CT, USA
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131
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Abstract
Rapid development in genome-wide transcriptional analyses has led to the discovery of a large number of non-coding transcripts, also called long non-coding RNA (lncRNA). LncRNAs harbor biological activities including regulation of protein-coding gene expression at epigenetic, transcriptional and post-transcriptional levels. They also take a part in various physiological and pathological processes, participating in cell development, immunity, disease processes and oncogenesis. Here I discuss and summarize, current knowledge about lncRNA origin, function and involvement in human disease.
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Affiliation(s)
- Kyriacos Felekkis
- Department of Life and Health Sciences and University of Nicosia Medical School, University of Nicosia, Nicosia, Cyprus
| | - Konstantinos Voskarides
- Department of Biological Sciences, Molecular Medicine Research Center, University of Cyprus, Nicosia, Cyprus
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132
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Chan HYE. RNA-mediated pathogenic mechanisms in polyglutamine diseases and amyotrophic lateral sclerosis. Front Cell Neurosci 2014; 8:431. [PMID: 25565965 PMCID: PMC4271607 DOI: 10.3389/fncel.2014.00431] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/29/2014] [Indexed: 12/12/2022] Open
Abstract
Gene transcription produces a wide variety of ribonucleic acid (RNA) species in eukaryotes. Individual types of RNA, such as messenger, structural and regulatory RNA, are known to play distinct roles in the cell. Recently, researchers have identified a large number of RNA-mediated toxicity pathways that play significant pathogenic roles in numerous human disorders. In this article, we describe various common RNA toxicity pathways, namely epigenetic gene silencing, nucleolar stress, nucleocytoplasmic transport, bi-directional gene transcription, repeat-associated non-ATG translation, RNA foci formation and cellular protein sequestration. We emphasize RNA toxicity mechanisms that involve nucleotide repeat expansion, such as those related to polyglutamine (polyQ) disorders and frontotemporal lobar degeneration-amyotrophic lateral sclerosis.
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Affiliation(s)
- Ho Yin Edwin Chan
- Laboratory of Drosophila Research, School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong Hong Kong, China ; Biochemistry Programme, School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong Hong Kong, China
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133
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Differential lncRNA expression profiles in brown and white adipose tissues. Mol Genet Genomics 2014; 290:699-707. [DOI: 10.1007/s00438-014-0954-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 11/10/2014] [Indexed: 02/03/2023]
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134
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Abstract
Heredoataxias are a group of genetic disorders with a cerebellar syndrome as the leading clinical manifestation. The current classification distinguishes heredoataxias according to the trait of inheritance into autosomal dominant, autosomal recessive, X-linked, and maternally inherited heredoataxias. The autosomal dominant heredoataxias are separated into spinocerebellar ataxias (SCA1-8, 10-15, 17-23, 25-30, and dentato-rubro-pallido-luysian atrophy), episodic ataxias (EA1-7), and autosomal dominant mitochondrial heredoataxias (Leigh syndrome, MIRAS, ADOAD, and AD-CPEO). The autosomal recessive ataxias are separated into Friedreich ataxia, ataxia due to vitamin E deficiency, ataxia due to Abeta-lipoproteinemia, Refsum disease, late-onset Tay-Sachs disease, cerebrotendineous xanthomatosis, spinocerebellar ataxia with axonal neuropathy, ataxia telangiectasia, ataxia telangiectasia-like disorder, ataxia with oculomotor apraxia 1 and 2, spastic ataxia of Charlevoix-Saguenay, Cayman ataxia, Marinesco-Sjögren syndrome, and autosomal recessive mitochondrial ataxias (AR-CPEO, SANDO, SCAE, AHS, IOSCA, MEMSA, LBSL CoQ-deficiency, PDC-deficiency). Only two of the heredoataxias, fragile X/tremor/ataxia syndrome, and XLSA/A are transmitted via an X-linked trait. Maternally inherited heredoataxias are due to point mutations in genes encoding for tRNAs, rRNAs, respiratory chain subunits or single large scale deletions/duplications of the mitochondrial DNA and include MELAS, MERRF, KSS, PS, MILS, NARP, and non-syndromic mitochondrial disorders. Treatment of heredoataxias is symptomatic and supportive and may have a beneficial effect in single patients.**Please see page 424 for abbreviation list.
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135
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Kung PJ, Tao YC, Hsu HC, Chen WL, Lin TH, Janreddy D, Yao CF, Chang KH, Lin JY, Su MT, Wu CH, Lee-Chen GJ, Hsieh-Li HM. Indole and synthetic derivative activate chaperone expression to reduce polyQ aggregation in SCA17 neuronal cell and slice culture models. DRUG DESIGN DEVELOPMENT AND THERAPY 2014; 8:1929-39. [PMID: 25342886 PMCID: PMC4206201 DOI: 10.2147/dddt.s67376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In spinocerebellar ataxia type 17 (SCA17), the expansion of a translated CAG repeat in the TATA box binding protein (TBP) gene results in a long polyglutamine (polyQ) tract in the TBP protein, leading to intracellular accumulation of aggregated TBP and cell death. The molecular chaperones act in preventing protein aggregation to ameliorate downstream harmful events. In this study, we used Tet-On SH-SY5Y cells with inducible SCA17 TBP/Q79-green fluorescent protein (GFP) expression to test indole and synthetic derivative NC001-8 for neuroprotection. We found that indole and NC001-8 up-regulated chaperone expression to reduce polyQ aggregation in neuronal differentiated TBP/Q79 cells. The effects on promoting neurite outgrowth and on reduction of aggregation on Purkinje cells were also confirmed with cerebellar primary and slice cultures of SCA17 transgenic mice. Our results demonstrate how indole and derivative NC001-8 reduce polyQ aggregation to support their therapeutic potentials in SCA17 treatment.
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Affiliation(s)
- Pin-Jui Kung
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Yu-Chen Tao
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ho-Chiang Hsu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Wan-Ling Chen
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Te-Hsien Lin
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Donala Janreddy
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Ching-Fa Yao
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Kuo-Hsuan Chang
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei, Taiwan
| | - Jung-Yaw Lin
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ming-Tsan Su
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Chung-Hsin Wu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Guey-Jen Lee-Chen
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Hsiu-Mei Hsieh-Li
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
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136
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Lin CH, Wu YR, Kung PJ, Chen WL, Lee LC, Lin TH, Chao CY, Chen CM, Chang KH, Janreddy D, Lee-Chen GJ, Yao CF. The potential of indole and a synthetic derivative for polyQ aggregation reduction by enhancement of the chaperone and autophagy systems. ACS Chem Neurosci 2014; 5:1063-74. [PMID: 25197952 DOI: 10.1021/cn500075u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In polyglutamine (polyQ)-mediated disorders, the expansion of translated CAG repeats in the disease genes result in long polyQ tracts in their respective proteins, leading to intracellular accumulation of aggregated polyQ proteins, production of reactive oxygen species, and cell death. The molecular chaperones act in preventing protein misfolding and aggregation, thus inhibiting a wide range of harmful downstream events. In the circumstance of accumulation of aggregated polyQ proteins, the autophagic pathway is induced to degrade the misfolded or aggregated proteins. In this study, we used Flp-In 293/SH-SY5Y cells with inducible SCA3 ATXN3/Q75-GFP expression to test the effect of indole and synthetic derivatives for neuroprotection. We found that ATXN3/Q75 aggregation can be significantly prohibited in Flp-In 293 cells by indole and derivative NC001-8. Meanwhile, indole and NC001-8 up-regulated chaperones and autophagy in the same cell models. Both of them further promote neurite outgrowth in neuronal differentiated SH-SY5Y ATXN3/Q75-GFP cells. Our results demonstrate how indole and derivative NC001-8 are likely to work in reduction of polyQ-aggregation and provide insight into the possible effectual mechanism of indole compounds in polyQ spinocerebellar ataxia (SCA) patients. These findings may have therapeutic applications in a broad range of clinical situations.
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Affiliation(s)
- Chih-Hsin Lin
- Department
of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei 10507, Taiwan
| | - Yih-Ru Wu
- Department
of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei 10507, Taiwan
| | | | - Wan-Ling Chen
- Department
of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei 10507, Taiwan
| | | | | | - Chih-Ying Chao
- Department
of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei 10507, Taiwan
| | - Chiung-Mei Chen
- Department
of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei 10507, Taiwan
| | - Kuo-Hsuan Chang
- Department
of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei 10507, Taiwan
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137
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Kearse MG, Todd PK. Repeat-associated non-AUG translation and its impact in neurodegenerative disease. Neurotherapeutics 2014; 11:721-31. [PMID: 25005000 PMCID: PMC4391382 DOI: 10.1007/s13311-014-0292-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Nucleotide repeat expansions underlie numerous human neurological disorders. Repeats can trigger toxicity through multiple pathogenic mechanisms, including RNA gain-of-function, protein gain-of-function, and protein loss-of-function pathways. Traditionally, inference of the underlying pathogenic mechanism derives from the repeat location, with dominantly inherited repeats within transcribed noncoding sequences eliciting toxicity predominantly as RNA via sequestration of specific RNA binding proteins. However, recent findings question this assumption and suggest that repeats outside of annotated open reading frames may also trigger toxicity through a novel form of protein translational initiation known as repeat-associated non-AUG (RAN) translation. To date, RAN translation has been implicated in 4 nucleotide repeat expansion disorders: spinocerebellar ataxia type 8; myotonic dystrophy type 1 with CTG•CAG repeats; C9orf72 amyotrophic lateral sclerosis/frontotemporal dementia with GGGGCC•GGCCCC repeats; and fragile X-associated tremor/ataxia syndrome with CGG repeats. RAN translation contributes to hallmark pathological characteristics in these disorders by producing homopolymeric or dipeptide repeat proteins. Here, we review what is known about RAN translation, with an emphasis on how differences in both repeat sequence and context may confer different requirements for unconventional initiation. We then discuss how this new mechanism of translational initiation might function in normal physiology and lay out a roadmap for addressing the numerous questions that remain.
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Affiliation(s)
- Michael G. Kearse
- />Department of Neurology, University of Michigan Medical School, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200 USA
| | - Peter K. Todd
- />Department of Neurology, University of Michigan Medical School, 4005 BSRB, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200 USA
- />Veterans Affairs Medical Center, Ann Arbor, MI 48105 USA
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138
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Kino Y, Washizu C, Kurosawa M, Oma Y, Hattori N, Ishiura S, Nukina N. Nuclear localization of MBNL1: splicing-mediated autoregulation and repression of repeat-derived aberrant proteins. Hum Mol Genet 2014; 24:740-56. [PMID: 25274774 DOI: 10.1093/hmg/ddu492] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In some neurological diseases caused by repeat expansions such as myotonic dystrophy, the RNA-binding protein muscleblind-like 1 (MBNL1) accumulates in intranuclear inclusions containing mutant repeat RNA. The interaction between MBNL1 and mutant RNA in the nucleus is a key event leading to loss of MBNL function, yet the details of this effect have been elusive. Here, we investigated the mechanism and significance of MBNL1 nuclear localization. We found that MBNL1 contains two classes of nuclear localization signal (NLS), a classical bipartite NLS and a novel conformational NLS. Alternative splicing of exon 7 acts as a switch between these NLS types and couples MBNL1 activity and intracellular localization. Depending on its nuclear localization, MBNL1 promoted nuclear accumulation of mutant RNA containing a CUG or CAG repeat, some of which produced proteins containing homopolymeric tracts such as polyglutamine. Furthermore, MBNL1 repressed the expression of these homopolymeric proteins including those presumably produced through repeat-associated non-ATG (RAN) translation. These results suggest that nuclear retention of expanded RNA reflects a novel role of MBNL proteins in repressing aberrant protein expression and may provide pathological and therapeutic implications for a wide range of repeat expansion diseases associated with nuclear RNA retention and/or RAN translation.
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Affiliation(s)
- Yoshihiro Kino
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-0033, Japan CREST (Core Research for Evolutionary Science and Technology), JST, Saitama 332-0012, Japan Laboratory for Structural Neuropathology, Brain Science Institute, RIKEN, Saitama 351-0198, Japan Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Tokyo 204-8588, Japan and
| | - Chika Washizu
- Laboratory for Structural Neuropathology, Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Masaru Kurosawa
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-0033, Japan CREST (Core Research for Evolutionary Science and Technology), JST, Saitama 332-0012, Japan Laboratory for Structural Neuropathology, Brain Science Institute, RIKEN, Saitama 351-0198, Japan
| | - Yoko Oma
- Department of Life Sciences, Graduate School of Arts and Sciences, the University of Tokyo, Tokyo 153-8902, Japan
| | - Nobutaka Hattori
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-0033, Japan
| | - Shoichi Ishiura
- Department of Life Sciences, Graduate School of Arts and Sciences, the University of Tokyo, Tokyo 153-8902, Japan
| | - Nobuyuki Nukina
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-0033, Japan CREST (Core Research for Evolutionary Science and Technology), JST, Saitama 332-0012, Japan Laboratory for Structural Neuropathology, Brain Science Institute, RIKEN, Saitama 351-0198, Japan
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139
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Wojciechowska M, Olejniczak M, Galka-Marciniak P, Jazurek M, Krzyzosiak WJ. RAN translation and frameshifting as translational challenges at simple repeats of human neurodegenerative disorders. Nucleic Acids Res 2014; 42:11849-64. [PMID: 25217582 PMCID: PMC4231732 DOI: 10.1093/nar/gku794] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Repeat-associated disorders caused by expansions of short sequences have been classified as coding and noncoding and are thought to be caused by protein gain-of-function and RNA gain-of-function mechanisms, respectively. The boundary between such classifications has recently been blurred by the discovery of repeat-associated non-AUG (RAN) translation reported in spinocerebellar ataxia type 8, myotonic dystrophy type 1, fragile X tremor/ataxia syndrome and C9ORF72 amyotrophic lateral sclerosis and frontotemporal dementia. This noncanonical translation requires no AUG start codon and can initiate in multiple frames of CAG, CGG and GGGGCC repeats of the sense and antisense strands of disease-relevant transcripts. RNA structures formed by the repeats have been suggested as possible triggers; however, the precise mechanism of the translation initiation remains elusive. Templates containing expansions of microsatellites have also been shown to challenge translation elongation, as frameshifting has been recognized across CAG repeats in spinocerebellar ataxia type 3 and Huntington's disease. Determining the critical requirements for RAN translation and frameshifting is essential to decipher the mechanisms that govern these processes. The contribution of unusual translation products to pathogenesis needs to be better understood. In this review, we present current knowledge regarding RAN translation and frameshifting and discuss the proposed mechanisms of translational challenges imposed by simple repeat expansions.
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Affiliation(s)
- Marzena Wojciechowska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Marta Olejniczak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Paulina Galka-Marciniak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Magdalena Jazurek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
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140
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Duan R, Sharma S, Xia Q, Garber K, Jin P. Towards Understanding RNA-Mediated Neurological Disorders. J Genet Genomics 2014; 41:473-84. [DOI: 10.1016/j.jgg.2014.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 08/10/2014] [Accepted: 08/12/2014] [Indexed: 12/14/2022]
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141
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Wen J, Scoles DR, Facelli JC. Structure prediction of polyglutamine disease proteins: comparison of methods. BMC Bioinformatics 2014; 15 Suppl 7:S11. [PMID: 25080018 PMCID: PMC4110737 DOI: 10.1186/1471-2105-15-s7-s11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Background The expansion of polyglutamine (poly-Q) repeats in several unrelated proteins is associated with at least ten neurodegenerative diseases. The length of the poly-Q regions plays an important role in the progression of the diseases. The number of glutamines (Q) is inversely related to the onset age of these polyglutamine diseases, and the expansion of poly-Q repeats has been associated with protein misfolding. However, very little is known about the structural changes induced by the expansion of the repeats. Computational methods can provide an alternative to determine the structure of these poly-Q proteins, but it is important to evaluate their performance before large scale prediction work is done. Results In this paper, two popular protein structure prediction programs, I-TASSER and Rosetta, have been used to predict the structure of the N-terminal fragment of a protein associated with Huntington's disease with 17 glutamines. Results show that both programs have the ability to find the native structures, but I-TASSER performs better for the overall task. Conclusions Both I-TASSER and Rosetta can be used for structure prediction of proteins with poly-Q repeats. Knowledge of poly-Q structure may significantly contribute to development of therapeutic strategies for poly-Q diseases.
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142
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Combes RD, Balls M. Every silver lining has a cloud: the scientific and animal welfare issues surrounding a new approach to the production of transgenic animals. Altern Lab Anim 2014; 42:137-45. [PMID: 24901907 DOI: 10.1177/026119291404200206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The scientific basis and advantages of using recently developed CRISPR/Cas-9 technology for transgenesis have been assessed with respect to other production methods, laboratory animal welfare, and the scientific relevance of transgenic models of human diseases in general. As the new technology is straightforward, causes targeted DNA double strand breaks and can result in homozygous changes in a single step, it is more accurate and more efficient than other production methods and speeds up transgenesis. CRISPR/Cas-9 also obviates the use of embryonic stem cells, and is being used to generate transgenic non-human primates (NHPs). While the use of this method reduces the level of animal wastage resulting from the production of each new strain, any long-term contribution to reduction will be offset by the overall increase in the numbers of transgenic animals likely to result from its widespread usage. Likewise, the contribution to refinement of using a more-precise technique, thereby minimising the occurrence of unwanted genetic effects, will be countered by a probable substantial increase in the production of transgenic strains of increasingly sentient species. For ethical and welfare reasons, we believe that the generation of transgenic NHPs should be allowed only in extremely exceptional circumstances. In addition, we present information, which, on both welfare and scientific grounds, leads us to question the current policy of generating ever-more new transgenic models in light of the general failure of many of them, after over two decades of ubiquitous use, to result in significant advances in the understanding and treatment of many key human diseases. Because this unsatisfactory situation is likely to be due to inherent, as well as possibly avoidable, limitations in the transgenic approach to studying disease, which are briefly reviewed, it is concluded that a thorough reappraisal of the rationale for using genetically-altered animals in fundamental research and by the pharmaceutical industry, and for its support by funding bodies, should be undertaken. In the meantime, the use of CRISPR/Cas-9 to generate new transgenic cells in culture is to be guardedly encouraged.
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143
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Convergent transcription through microsatellite repeat tracts induces cell death. Mol Biol Rep 2014; 41:5627-34. [PMID: 25012912 DOI: 10.1007/s11033-014-3432-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 05/24/2014] [Indexed: 10/25/2022]
Abstract
Microsatellite sequences, composed of short tandem repeats and randomly distributed in human genome, can become unstable during various DNA metabolic processes. Expansions of CAG, GAA, CGG and CCTG repeats located in specific genes are responsible for several human disorders. It is known that a major percentage of human genes simultaneously express both sense and antisense transcripts. Recently, we reported that convergent transcription through a CAG95 tract in human cells leads to cell cycle arrest as well as robust apoptosis. In this study, we studied the effects of convergent transcription through other types of repeats, using cell lines that contain substrates with inducible sense and antisense transcription through CGG66, GAA102, or CCTG134 tracts. We found that convergent transcription through all these repeats inhibits cell growth and induces cell death, though more moderately than convergent transcription through a CAG tract. These results suggest that convergent transcription through various types of tandem repeats represent a novel type of stress to cells.
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144
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Sun X, Marque LO, Cordner Z, Pruitt JL, Bhat M, Li PP, Kannan G, Ladenheim EE, Moran TH, Margolis RL, Rudnicki DD. Phosphorodiamidate morpholino oligomers suppress mutant huntingtin expression and attenuate neurotoxicity. Hum Mol Genet 2014; 23:6302-17. [PMID: 25035419 DOI: 10.1093/hmg/ddu349] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin (HTT) gene. Disease pathogenesis derives, at least in part, from the long polyglutamine tract encoded by mutant HTT. Therefore, considerable effort has been dedicated to the development of therapeutic strategies that significantly reduce the expression of the mutant HTT protein. Antisense oligonucleotides (ASOs) targeted to the CAG repeat region of HTT transcripts have been of particular interest due to their potential capacity to discriminate between normal and mutant HTT transcripts. Here, we focus on phosphorodiamidate morpholino oligomers (PMOs), ASOs that are especially stable, highly soluble and non-toxic. We designed three PMOs to selectively target expanded CAG repeat tracts (CTG22, CTG25 and CTG28), and two PMOs to selectively target sequences flanking the HTT CAG repeat (HTTex1a and HTTex1b). In HD patient-derived fibroblasts with expanded alleles containing 44, 77 or 109 CAG repeats, HTTex1a and HTTex1b were effective in suppressing the expression of mutant and non-mutant transcripts. CTGn PMOs also suppressed HTT expression, with the extent of suppression and the specificity for mutant transcripts dependent on the length of the targeted CAG repeat and on the CTG repeat length and concentration of the PMO. PMO CTG25 reduced HTT-induced cytotoxicity in vitro and suppressed mutant HTT expression in vivo in the N171-82Q transgenic mouse model. Finally, CTG28 reduced mutant HTT expression and improved the phenotype of Hdh(Q7/Q150) knock-in HD mice. These data demonstrate the potential of PMOs as an approach to suppressing the expression of mutant HTT.
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Affiliation(s)
- Xin Sun
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Leonard O Marque
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Zachary Cordner
- Behavioral Neuroscience Laboratory, Department of Psychiatry and Behavioral Sciences
| | - Jennifer L Pruitt
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Manik Bhat
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Pan P Li
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Geetha Kannan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences
| | - Ellen E Ladenheim
- Behavioral Neuroscience Laboratory, Department of Psychiatry and Behavioral Sciences
| | - Timothy H Moran
- Behavioral Neuroscience Laboratory, Department of Psychiatry and Behavioral Sciences
| | - Russell L Margolis
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Department of Neurology, and Program of Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Dobrila D Rudnicki
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Program of Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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145
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Sandi C, Sandi M, Anjomani Virmouni S, Al-Mahdawi S, Pook MA. Epigenetic-based therapies for Friedreich ataxia. Front Genet 2014; 5:165. [PMID: 24917884 PMCID: PMC4042889 DOI: 10.3389/fgene.2014.00165] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/19/2014] [Indexed: 11/29/2022] Open
Abstract
Friedreich ataxia (FRDA) is a lethal autosomal recessive neurodegenerative disorder caused primarily by a homozygous GAA repeat expansion mutation within the first intron of the FXN gene, leading to inhibition of FXN transcription and thus reduced frataxin protein expression. Recent studies have shown that epigenetic marks, comprising chemical modifications of DNA and histones, are associated with FXN gene silencing. Such epigenetic marks can be reversed, making them suitable targets for epigenetic-based therapy. Furthermore, since FRDA is caused by insufficient, but functional, frataxin protein, epigenetic-based transcriptional re-activation of the FXN gene is an attractive therapeutic option. In this review we summarize our current understanding of the epigenetic basis of FXN gene silencing and we discuss current epigenetic-based FRDA therapeutic strategies.
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Affiliation(s)
| | | | | | | | - Mark A. Pook
- Division of Biosciences, School of Health Sciences and Social Care, Brunel University LondonUxbridge, UK
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146
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Evers MM, Toonen LJA, van Roon-Mom WMC. Ataxin-3 protein and RNA toxicity in spinocerebellar ataxia type 3: current insights and emerging therapeutic strategies. Mol Neurobiol 2014; 49:1513-31. [PMID: 24293103 PMCID: PMC4012159 DOI: 10.1007/s12035-013-8596-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/14/2013] [Indexed: 01/10/2023]
Abstract
Ataxin-3 is a ubiquitously expressed deubiqutinating enzyme with important functions in the proteasomal protein degradation pathway and regulation of transcription. The C-terminus of the ataxin-3 protein contains a polyglutamine (PolyQ) region that, when mutationally expanded to over 52 glutamines, causes the neurodegenerative disease spinocerebellar ataxia 3 (SCA3). In spite of extensive research, the molecular mechanisms underlying the cellular toxicity resulting from mutant ataxin-3 remain elusive and no preventive treatment is currently available. It has become clear over the last decade that the hallmark intracellular ataxin-3 aggregates are likely not the main toxic entity in SCA3. Instead, the soluble PolyQ containing fragments arising from proteolytic cleavage of ataxin-3 by caspases and calpains are now regarded to be of greater influence in pathogenesis. In addition, recent evidence suggests potential involvement of a RNA toxicity component in SCA3 and other PolyQ expansion disorders, increasing the pathogenic complexity. Herein, we review the functioning of ataxin-3 and the involvement of known protein and RNA toxicity mechanisms of mutant ataxin-3 that have been discovered, as well as future opportunities for therapeutic intervention.
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Affiliation(s)
- Melvin M. Evers
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Lodewijk J. A. Toonen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Willeke M. C. van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
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147
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Cleary JD, Ranum LPW. Repeat associated non-ATG (RAN) translation: new starts in microsatellite expansion disorders. Curr Opin Genet Dev 2014; 26:6-15. [PMID: 24852074 DOI: 10.1016/j.gde.2014.03.002] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 01/31/2014] [Accepted: 03/11/2014] [Indexed: 12/14/2022]
Abstract
Microsatellite-expansion diseases are a class of neurological and neuromuscular disorders caused by the expansion of short stretches of repetitive DNA (e.g. GGGGCC, CAG, CTG …) within the human genome. Since their discovery 20 years ago, research into how microsatellites expansions cause disease has been examined using the model that these genes are expressed in one direction and that expansion mutations only encode proteins when located in an ATG-initiated open reading frame. The fact that these mutations are often bidirectionally transcribed combined with the recent discovery of repeat associated non-ATG (RAN) translation provides new perspectives on how these expansion mutations are expressed and impact disease. Two expansion transcripts and a set of unexpected RAN proteins must now be considered for both coding and 'non-coding' expansion disorders. RAN proteins have been reported in a growing number of diseases, including spinocerebellar ataxia type 8 (SCA8), myotonic dystrophy type 1 (DM1), Fragile-X tremor ataxia syndrome (FXTAS), and C9ORF72 amyotrophic lateral sclerosis (ALS)/frontotemporal dementia (FTD).
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Affiliation(s)
- John Douglas Cleary
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA; Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA; Genetics Institute, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL, USA; Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA; Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, USA; Genetics Institute, College of Medicine, University of Florida, Gainesville, FL, USA.
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148
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Fiszer A, Krzyzosiak WJ. Oligonucleotide-based strategies to combat polyglutamine diseases. Nucleic Acids Res 2014; 42:6787-810. [PMID: 24848018 PMCID: PMC4066792 DOI: 10.1093/nar/gku385] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Considerable advances have been recently made in understanding the molecular aspects of pathogenesis and in developing therapeutic approaches for polyglutamine (polyQ) diseases. Studies on pathogenic mechanisms have extended our knowledge of mutant protein toxicity, confirmed the toxicity of mutant transcript and identified other toxic RNA and protein entities. One very promising therapeutic strategy is targeting the causative gene expression with oligonucleotide (ON) based tools. This straightforward approach aimed at halting the early steps in the cascade of pathogenic events has been widely tested for Huntington's disease and spinocerebellar ataxia type 3. In this review, we gather information on the use of antisense oligonucleotides and RNA interference triggers for the experimental treatment of polyQ diseases in cellular and animal models. We present studies testing non-allele-selective and allele-selective gene silencing strategies. The latter include targeting SNP variants associated with mutations or targeting the pathologically expanded CAG repeat directly. We compare gene silencing effectors of various types in a number of aspects, including their design, efficiency in cell culture experiments and pre-clinical testing. We discuss advantages, current limitations and perspectives of various ON-based strategies used to treat polyQ diseases.
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Affiliation(s)
- Agnieszka Fiszer
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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149
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Matilla-Dueñas A, Ashizawa T, Brice A, Magri S, McFarland KN, Pandolfo M, Pulst SM, Riess O, Rubinsztein DC, Schmidt J, Schmidt T, Scoles DR, Stevanin G, Taroni F, Underwood BR, Sánchez I. Consensus paper: pathological mechanisms underlying neurodegeneration in spinocerebellar ataxias. CEREBELLUM (LONDON, ENGLAND) 2014; 13:269-302. [PMID: 24307138 PMCID: PMC3943639 DOI: 10.1007/s12311-013-0539-y] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Intensive scientific research devoted in the recent years to understand the molecular mechanisms or neurodegeneration in spinocerebellar ataxias (SCAs) are identifying new pathways and targets providing new insights and a better understanding of the molecular pathogenesis in these diseases. In this consensus manuscript, the authors discuss their current views on the identified molecular processes causing or modulating the neurodegenerative phenotype in spinocerebellar ataxias with the common opinion of translating the new knowledge acquired into candidate targets for therapy. The following topics are discussed: transcription dysregulation, protein aggregation, autophagy, ion channels, the role of mitochondria, RNA toxicity, modulators of neurodegeneration and current therapeutic approaches. Overall point of consensus includes the common vision of neurodegeneration in SCAs as a multifactorial, progressive and reversible process, at least in early stages. Specific points of consensus include the role of the dysregulation of protein folding, transcription, bioenergetics, calcium handling and eventual cell death with apoptotic features of neurons during SCA disease progression. Unresolved questions include how the dysregulation of these pathways triggers the onset of symptoms and mediates disease progression since this understanding may allow effective treatments of SCAs within the window of reversibility to prevent early neuronal damage. Common opinions also include the need for clinical detection of early neuronal dysfunction, for more basic research to decipher the early neurodegenerative process in SCAs in order to give rise to new concepts for treatment strategies and for the translation of the results to preclinical studies and, thereafter, in clinical practice.
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Affiliation(s)
- A Matilla-Dueñas
- Health Sciences Research Institute Germans Trias i Pujol (IGTP), Ctra. de Can Ruti, Camí de les Escoles s/n, Badalona, Barcelona, Spain,
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150
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Vučićević D, Schrewe H, Orom UA. Molecular mechanisms of long ncRNAs in neurological disorders. Front Genet 2014; 5:48. [PMID: 24624135 PMCID: PMC3941653 DOI: 10.3389/fgene.2014.00048] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/15/2014] [Indexed: 01/02/2023] Open
Abstract
Long non-coding RNAs (ncRNAs) have added an unexpected layer of complexity in the regulation of gene expression. Mounting evidence now links long ncRNAs to fundamental biological processes such as development and differentiation, and recent research shows important involvement of long ncRNAs in a variety of diseases including neurodegenerative disorders, such as Parkinson’s, Alzheimer’s, spinocerebellar ataxia, and Huntington’s diseases. Furthermore, long ncRNAs are speculated to be implicated in development of psychiatric disorders such as schizophrenia and bipolar disorders. Long ncRNAs contribute to these disorders in diverse ways, from regulation of transcription to modulation of RNA processing and translation. In this review, we describe the diverse mechanisms reported for long ncRNAs, and discuss how they could mechanistically be involved in the development of neurological disorders.
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Affiliation(s)
- Dubravka Vučićević
- Otto Warburg Laboratory, Max Planck Institute for Molecular Genetics Berlin, Germany
| | - Heinrich Schrewe
- Department of Developmental Genetics, Max Planck Institute for Molecular Genetics Berlin, Germany
| | - Ulf A Orom
- Otto Warburg Laboratory, Max Planck Institute for Molecular Genetics Berlin, Germany
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