1
|
O'Brien BM, Moulick R, Jiménez-Avalos G, Rajasekaran N, Kaiser CM, Woodson SA. Stick-slip unfolding favors self-association of expanded HTT mRNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596809. [PMID: 38895475 PMCID: PMC11185545 DOI: 10.1101/2024.05.31.596809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
In Huntington's Disease (HD) and related disorders, expansion of CAG trinucleotide repeats produces a toxic gain of function in affected neurons. Expanded huntingtin (expHTT) mRNA forms aggregates that sequester essential RNA binding proteins, dysregulating mRNA processing and translation. The physical basis of RNA aggregation has been difficult to disentangle owing to the heterogeneous structure of the CAG repeats. Here, we probe the folding and unfolding pathways of expHTT mRNA using single-molecule force spectroscopy. Whereas normal HTT mRNAs unfold reversibly and cooperatively, expHTT mRNAs with 20 or 40 CAG repeats slip and unravel non-cooperatively at low tension. Slippage of CAG base pairs is punctuated by concerted rearrangement of adjacent CCG trinucleotides, trapping partially folded structures that readily base pair with another RNA strand. We suggest that the conformational entropy of the CAG repeats, combined with stable CCG base pairs, creates a stick-slip behavior that explains the aggregation propensity of expHTT mRNA.
Collapse
Affiliation(s)
- Brett M O'Brien
- Chemical Biology Interface Program, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Roumita Moulick
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Gabriel Jiménez-Avalos
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| | | | - Christian M Kaiser
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218 USA
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Sarah A Woodson
- Chemical Biology Interface Program, Johns Hopkins University, Baltimore, MD 21218 USA
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| |
Collapse
|
2
|
Teng Y, Zhu M, Qiu Z. G-Quadruplexes in Repeat Expansion Disorders. Int J Mol Sci 2023; 24:ijms24032375. [PMID: 36768697 PMCID: PMC9916761 DOI: 10.3390/ijms24032375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
The repeat expansions are the main genetic cause of various neurodegeneration diseases. More than ten kinds of repeat sequences with different lengths, locations, and structures have been confirmed in the past two decades. G-rich repeat sequences, such as CGG and GGGGCC, are reported to form functional G-quadruplexes, participating in many important bioprocesses. In this review, we conducted an overview concerning the contribution of G-quadruplex in repeat expansion disorders and summarized related mechanisms in current pathological studies, including the increasing genetic instabilities in replication and transcription, the toxic RNA foci formed in neurons, and the loss/gain function of proteins and peptides. Furthermore, novel strategies targeting G-quadruplex repeats were developed based on the understanding of disease mechanism. Small molecules and proteins binding to G-quadruplex in repeat expansions were investigated to protect neurons from dysfunction and delay the progression of neurodegeneration. In addition, the effects of environment on the stability of G-quadruplex were discussed, which might be critical factors in the pathological study of repeat expansion disorders.
Collapse
|
3
|
Dawson J, Baine-Savanhu FK, Ciosi M, Maxwell A, Monckton DG, Krause A. A probable cis-acting genetic modifier of Huntington disease frequent in individuals with African ancestry. HGG ADVANCES 2022; 3:100130. [PMID: 35935919 PMCID: PMC9352962 DOI: 10.1016/j.xhgg.2022.100130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 07/07/2022] [Indexed: 11/21/2022] Open
Abstract
Huntington disease (HD)is a dominantly inherited neurodegenerative disorder caused by the expansion of a polyglutamine encoding CAG repeat in the huntingtin gene. Recently, it has been established that disease severity in HD is best predicted by the number of pure CAG repeats rather than total glutamines encoded. Along with uncovering DNA repair gene variants as trans-acting modifiers of HD severity, these data reveal somatic expansion of the CAG repeat as a key driver of HD onset. Using high-throughput DNA sequencing, we have determined the precise sequence and somatic expansion profiles of the HTT repeat tract of 68 HD-affected and 158 HD-unaffected African ancestry individuals. A high level of HTT repeat sequence diversity was observed, with three likely African-specific alleles identified. In the most common disease allele (30 out of 68), the typical proline-encoding CCGCCA sequence was absent. This CCGCCA-loss disease allele was associated with an earlier age of diagnosis of approximately 7.1 years and occurred exclusively on haplotype B2. Although somatic expansion was associated with an earlier age of diagnosis in the study overall, the CCGCCA-loss disease allele displayed reduced somatic expansion relative to the typical HTT expansions in blood DNA. We propose that the CCGCCA loss occurring on haplotype B2 is an African cis-acting modifier that appears to alter disease diagnosis of HD through a mechanism that is not driven by somatic expansion. The assessment of a group of individuals from an understudied population has highlighted population-specific differences that emphasize the importance of studying genetically diverse populations in the context of disease.
Collapse
Affiliation(s)
- Jessica Dawson
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Fiona K. Baine-Savanhu
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
| | - Marc Ciosi
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Alastair Maxwell
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Darren G. Monckton
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2000, South Africa
- Corresponding author
| |
Collapse
|
4
|
Childs-Disney JL, Yang X, Gibaut QMR, Tong Y, Batey RT, Disney MD. Targeting RNA structures with small molecules. Nat Rev Drug Discov 2022; 21:736-762. [PMID: 35941229 PMCID: PMC9360655 DOI: 10.1038/s41573-022-00521-4] [Citation(s) in RCA: 159] [Impact Index Per Article: 79.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2022] [Indexed: 01/07/2023]
Abstract
RNA adopts 3D structures that confer varied functional roles in human biology and dysfunction in disease. Approaches to therapeutically target RNA structures with small molecules are being actively pursued, aided by key advances in the field including the development of computational tools that predict evolutionarily conserved RNA structures, as well as strategies that expand mode of action and facilitate interactions with cellular machinery. Existing RNA-targeted small molecules use a range of mechanisms including directing splicing - by acting as molecular glues with cellular proteins (such as branaplam and the FDA-approved risdiplam), inhibition of translation of undruggable proteins and deactivation of functional structures in noncoding RNAs. Here, we describe strategies to identify, validate and optimize small molecules that target the functional transcriptome, laying out a roadmap to advance these agents into the next decade.
Collapse
Affiliation(s)
| | - Xueyi Yang
- Department of Chemistry, Scripps Research, Jupiter, FL, USA
| | | | - Yuquan Tong
- Department of Chemistry, Scripps Research, Jupiter, FL, USA
| | - Robert T Batey
- Department of Biochemistry, University of Colorado, Boulder, CO, USA.
| | | |
Collapse
|
5
|
A Structural Potential of Rare Trinucleotide Repeat Tracts in RNA. Int J Mol Sci 2022; 23:ijms23105850. [PMID: 35628656 PMCID: PMC9144543 DOI: 10.3390/ijms23105850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 01/27/2023] Open
Abstract
Among types of trinucleotide repeats, there is some disproportion in the frequency of their occurrence in the human exome. This research presents new data describing the folding and thermodynamic stability of short, tandem RNA repeats of 23 types, focusing on the rare, yet poorly analyzed ones. UV-melting experiments included the presence of PEG or potassium and magnesium ions to determine their effect on the stability of RNA repeats structures. Rare repeats predominantly stayed single-stranded but had the potential for base pairing with other partially complementary repeat tracts. A coexistence of suitably complementary repeat types in a single RNA creates opportunities for interaction in the context of the secondary structure of RNA. We searched the human transcriptome for model RNAs in which different, particularly rare trinucleotide repeats coexist and selected the GABRA4 and CHIC1 RNAs to study intramolecular interactions between the repeat tracts that they contain. In vitro secondary structure probing results showed that the UAA and UUG repeat tracts, present in GABRA4 3' UTR, form a double helix, which separates one of its structural domains. For the RNA CHIC1 ORF fragment containing four short AGG repeat tracts and the CGU tract, we proved the formation of quadruplexes that blocked reverse transcription.
Collapse
|
6
|
Bush JA, Aikawa H, Fuerst R, Li Y, Ursu A, Meyer SM, Benhamou RI, Chen JL, Khan T, Wagner-Griffin S, Van Meter MJ, Tong Y, Olafson H, McKee KK, Childs-Disney JL, Gendron TF, Zhang Y, Coyne AN, Wang ET, Yildirim I, Wang KW, Petrucelli L, Rothstein JD, Disney MD. Ribonuclease recruitment using a small molecule reduced c9ALS/FTD r(G 4C 2) repeat expansion in vitro and in vivo ALS models. Sci Transl Med 2021; 13:eabd5991. [PMID: 34705518 DOI: 10.1126/scitranslmed.abd5991] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Jessica A Bush
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Haruo Aikawa
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Rita Fuerst
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Yue Li
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Andrei Ursu
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Samantha M Meyer
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Raphael I Benhamou
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Jonathan L Chen
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Tanya Khan
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Sarah Wagner-Griffin
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Montina J Van Meter
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Yuquan Tong
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Hailey Olafson
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Kendra K McKee
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jessica L Childs-Disney
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Yongjie Zhang
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Alyssa N Coyne
- Robert Packard Center for ALS Research, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Eric T Wang
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Ilyas Yildirim
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Kye Won Wang
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Jeffrey D Rothstein
- Robert Packard Center for ALS Research, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Matthew D Disney
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| |
Collapse
|
7
|
Umek T, Olsson T, Gissberg O, Saher O, Zaghloul EM, Lundin KE, Wengel J, Hanse E, Zetterberg H, Vizlin-Hodzic D, Smith CIE, Zain R. Oligonucleotides Targeting DNA Repeats Downregulate Huntingtin Gene Expression in Huntington's Patient-Derived Neural Model System. Nucleic Acid Ther 2021; 31:443-456. [PMID: 34520257 PMCID: PMC8713517 DOI: 10.1089/nat.2021.0021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Huntington's disease (HD) is one of the most common, dominantly inherited neurodegenerative disorders. It affects the striatum, cerebral cortex, and other subcortical structures leading to involuntary movement abnormalities, emotional disturbances, and cognitive impairments. HD is caused by a CAG•CTG trinucleotide-repeat expansion in exon 1 of the huntingtin (HTT) gene leading to the formation of mutant HTT (mtHTT) protein aggregates. Besides the toxicity of the mutated protein, there is also evidence that mtHTT transcripts contribute to the disease. Thus, the reduction of both mutated mRNA and protein would be most beneficial as a treatment. Previously, we designed a novel anti-gene oligonucleotide (AGO)-based strategy directly targeting the HTT trinucleotide-repeats in DNA and reported downregulation of mRNA and protein in HD patient fibroblasts. In this study, we differentiate HD patient-derived induced pluripotent stem cells to investigate the efficacy of the AGO, a DNA/Locked Nucleic Acid mixmer with phosphorothioate backbone, to modulate HTT transcription during neural in vitro development. For the first time, we demonstrate downregulation of HTT mRNA following both naked and magnetofected delivery into neural stem cells (NSCs) and show that neither emergence of neural rosette structures nor self-renewal of NSCs is compromised. Furthermore, the inhibition potency of both HTT mRNA and protein without off-target effects is confirmed in neurons. These results further validate an anti-gene approach for the treatment of HD.
Collapse
Affiliation(s)
- Tea Umek
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden
| | - Thomas Olsson
- Department of Physiology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,Department of Clinical Pathology and Cytology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Olof Gissberg
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden
| | - Osama Saher
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden.,Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Eman M Zaghloul
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden.,Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Karin E Lundin
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden
| | - Jesper Wengel
- Department of Physics, Chemistry and Pharmacy, Biomolecular Nanoscale Engineering Center, University of Southern Denmark, Odense M, Denmark
| | - Eric Hanse
- Department of Physiology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, United Kingdom.,Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,UK Dementia Research Institute at UCL, London, United Kingdom
| | - Dzeneta Vizlin-Hodzic
- Department of Physiology, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.,Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - C I Edvard Smith
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden
| | - Rula Zain
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden.,Department of Clinical Genetics, Center for Rare Diseases, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
8
|
Abstract
RNA lies upstream of nearly all biology and functions as the central conduit of information exchange in all cells. RNA molecules encode information both in their primary sequences and in complex structures that form when an RNA folds back on itself. From the time of discovery of mRNA in the late 1950s until quite recently, we had only a rudimentary understanding of RNA structure across vast regions of most messenger and noncoding RNAs. This deficit is now rapidly being addressed, especially by selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) chemistry, mutational profiling (MaP), and closely related platform technologies that, collectively, create chemical microscopes for RNA. These technologies make it possible to interrogate RNA structure, quantitatively, at nucleotide resolution, and at large scales, for entire mRNAs, noncoding RNAs, and viral RNA genomes. By applying comprehensive structure probing to diverse problems, we and others are showing that control of biological function mediated by RNA structure is ubiquitous across prokaryotic and eukaryotic organisms.Work over the past decade using SHAPE-based analyses has clarified key principles. First, the method of RNA structure probing matters. SHAPE-MaP, with its direct and one-step readout that probes nearly every nucleotide by reaction at the 2'-hydroxyl, gives a more detailed and accurate readout than alternatives. Second, comprehensive chemical probing is essential. Focusing on fragments of large RNAs or using meta-gene or statistical analyses to compensate for sparse data sets misses critical features and often yields structure models with poor predictive power. Finally, every RNA has its own internal structural personality. There are myriad ways in which RNA structure modulates sequence accessibility, protein binding, translation, splice-site choice, phase separation, and other fundamental biological processes. In essentially every instance where we have applied rigorous and quantitative SHAPE technologies to study RNA structure-function interrelationships, new insights regarding biological regulatory mechanisms have emerged. RNA elements with more complex higher-order structures appear more likely to contain high-information-content clefts and pockets that bind small molecules, broadly informing a vigorous field of RNA-targeted drug discovery.The broad implications of this collective work are twofold. First, it is long past time to abandon depiction of large RNAs as simple noodle-like or gently flowing molecules. Instead, we need to emphasize that nearly all RNAs are punctuated with distinctive internal structures, a subset of which modulate function in profound ways. Second, structure probing should be an integral component of any effort that seeks to understand the functional nexuses and biological roles of large RNAs.
Collapse
Affiliation(s)
- Kevin M. Weeks
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| |
Collapse
|
9
|
Tavares RDCA, Mahadeshwar G, Wan H, Huston NC, Pyle AM. The global and local distribution of RNA structure throughout the SARS-CoV-2 genome. J Virol 2021; 95:JVI.02190-20. [PMID: 33268519 PMCID: PMC8092842 DOI: 10.1128/jvi.02190-20] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 11/30/2020] [Indexed: 02/08/2023] Open
Abstract
SARS-CoV-2 is the causative viral agent of COVID-19, the disease at the center of the current global pandemic. While knowledge of highly structured regions is integral for mechanistic insights into the viral infection cycle, very little is known about the location and folding stability of functional elements within the massive, ∼30kb SARS-CoV-2 RNA genome. In this study, we analyze the folding stability of this RNA genome relative to the structural landscape of other well-known viral RNAs. We present an in-silico pipeline to predict regions of high base pair content across long genomes and to pinpoint hotspots of well-defined RNA structures, a method that allows for direct comparisons of RNA structural complexity within the several domains in SARS-CoV-2 genome. We report that the SARS-CoV-2 genomic propensity for stable RNA folding is exceptional among RNA viruses, superseding even that of HCV, one of the most structured viral RNAs in nature. Furthermore, our analysis suggests varying levels of RNA structure across genomic functional regions, with accessory and structural ORFs containing the highest structural density in the viral genome. Finally, we take a step further to examine how individual RNA structures formed by these ORFs are affected by the differences in genomic and subgenomic contexts, which given the technical difficulty of experimentally separating cellular mixtures of sgRNA from gRNA, is a unique advantage of our in-silico pipeline. The resulting findings provide a useful roadmap for planning focused empirical studies of SARS-CoV-2 RNA biology, and a preliminary guide for exploring potential SARS-CoV-2 RNA drug targets.Importance The RNA genome of SARS-CoV-2 is among the largest and most complex viral genomes, and yet its RNA structural features remain relatively unexplored. Since RNA elements guide function in most RNA viruses, and they represent potential drug targets, it is essential to chart the architectural features of SARS-CoV-2 and pinpoint regions that merit focused study. Here we show that RNA folding stability of SARS-CoV-2 genome is exceptional among viral genomes and we develop a method to directly compare levels of predicted secondary structure across SARS-CoV-2 domains. Remarkably, we find that coding regions display the highest structural propensity in the genome, forming motifs that differ between the genomic and subgenomic contexts. Our approach provides an attractive strategy to rapidly screen for candidate structured regions based on base pairing potential and provides a readily interpretable roadmap to guide functional studies of RNA viruses and other pharmacologically relevant RNA transcripts.
Collapse
Affiliation(s)
| | - Gandhar Mahadeshwar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Han Wan
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
| | - Nicholas C Huston
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Anna Marie Pyle
- Department of Chemistry, Yale University, New Haven, CT 06511, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06511, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| |
Collapse
|
10
|
Monckton DG. The Contribution of Somatic Expansion of the CAG Repeat to Symptomatic Development in Huntington's Disease: A Historical Perspective. J Huntingtons Dis 2021; 10:7-33. [PMID: 33579863 PMCID: PMC7990401 DOI: 10.3233/jhd-200429] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery in the early 1990s of the expansion of unstable simple sequence repeats as the causative mutation for a number of inherited human disorders, including Huntington's disease (HD), opened up a new era of human genetics and provided explanations for some old problems. In particular, an inverse association between the number of repeats inherited and age at onset, and unprecedented levels of germline instability, biased toward further expansion, provided an explanation for the wide symptomatic variability and anticipation observed in HD and many of these disorders. The repeats were also revealed to be somatically unstable in a process that is expansion-biased, age-dependent and tissue-specific, features that are now increasingly recognised as contributory to the age-dependence, progressive nature and tissue specificity of the symptoms of HD, and at least some related disorders. With much of the data deriving from affected individuals, and model systems, somatic expansions have been revealed to arise in a cell division-independent manner in critical target tissues via a mechanism involving key components of the DNA mismatch repair pathway. These insights have opened new approaches to thinking about how the disease could be treated by suppressing somatic expansion and revealed novel protein targets for intervention. Exciting times lie ahead in turning these insights into novel therapies for HD and related disorders.
Collapse
Affiliation(s)
- Darren G. Monckton
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| |
Collapse
|
11
|
Maiuri T, Hung CL, Suart C, Begeja N, Barba-Bazan C, Peng Y, Savic N, Wong T, Truant R. DNA Repair in Huntington's Disease and Spinocerebellar Ataxias: Somatic Instability and Alternative Hypotheses. J Huntingtons Dis 2021; 10:165-173. [PMID: 33579859 PMCID: PMC7990435 DOI: 10.3233/jhd-200414] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The use of genome wide association studies (GWAS) in Huntington's disease (HD) research, driven by unbiased human data analysis, has transformed the focus of new targets that could affect age at onset. While there is a significant depth of information on DNA damage repair, with many drugs and drug targets, most of this development has taken place in the context of cancer therapy. DNA damage repair in neurons does not rely on DNA replication correction mechanisms. However, there is a strong connection between DNA repair and neuronal metabolism, mediated by nucleotide salvaging and the poly ADP-ribose (PAR) response, and this connection has been implicated in other age-onset neurodegenerative diseases. Validation of leads including the mismatch repair protein MSH3, and interstrand cross-link repair protein FAN1, suggest the mechanism is driven by somatic CAG instability, which is supported by the protective effect of CAA substitutions in the CAG tract. We currently do not understand: how somatic instability is triggered; the state of DNA damage within expanding alleles in the brain; whether this damage induces mismatch repair and interstrand cross-link pathways; whether instability mediates toxicity, and how this relates to human ageing. We discuss DNA damage pathways uncovered by HD GWAS, known roles of other polyglutamine disease proteins in DNA damage repair, and a panel of hypotheses for pathogenic mechanisms.
Collapse
Affiliation(s)
- Tamara Maiuri
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Claudia L.K. Hung
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Celeste Suart
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Nola Begeja
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Carlos Barba-Bazan
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Yi Peng
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Natasha Savic
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Timothy Wong
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| | - Ray Truant
- McMaster University, Department of Biochemistry and Biomedical Sciences, Hamilton, Ontario, Canada
| |
Collapse
|
12
|
van Cruchten RTP, Wansink DG. In Vitro Synthesis and RNA Structure Probing of CUG Triplet Repeat RNA. Methods Mol Biol 2020; 2056:187-202. [PMID: 31586349 DOI: 10.1007/978-1-4939-9784-8_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aberrant RNA structure plays a central role in the molecular mechanisms guided by repeat RNAs in diseases like myotonic dystrophy (DM), C9orf72-linked amyotrophic lateral sclerosis (ALS) and fragile X tremor/ataxia syndrome (FXTAS). Much knowledge remains to be gained about how these repeat-expanded transcripts are actually folded, especially regarding the properties specific to very long and interrupted repeats. RNA structure can be interrogated by chemical as well as enzymatic probes. These probes usually bind or cleave single-stranded nucleotides, which can subsequently be detected using reverse transcriptase primer extension. In this chapter, we describe methodology for in vitro synthesis and structure probing of expanded CUG repeat RNAs associated with DM type 1 and approaches for the associated data analysis.
Collapse
Affiliation(s)
- Remco T P van Cruchten
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| |
Collapse
|
13
|
Palomino‐Hernandez O, Margreiter MA, Rossetti G. Challenges in RNA Regulation in Huntington's Disease: Insights from Computational Studies. Isr J Chem 2020. [DOI: 10.1002/ijch.202000021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Oscar Palomino‐Hernandez
- Computational Biomedicine, Institute of Neuroscience and Medicine (INM-9)/Instute for advanced simulations (IAS-5)Forschungszentrum Juelich 52425 Jülich Germany
- Faculty 1RWTH Aachen 52425 Aachen Germany
- Computation-based Science and Technology Research CenterThe Cyprus Institute Nicosia 2121 Cyprus
- Institute of Life ScienceThe Hebrew University of Jerusalem Jerusalem 91904 Israel
| | - Michael A. Margreiter
- Computational Biomedicine, Institute of Neuroscience and Medicine (INM-9)/Instute for advanced simulations (IAS-5)Forschungszentrum Juelich 52425 Jülich Germany
- Faculty 1RWTH Aachen 52425 Aachen Germany
| | - Giulia Rossetti
- Computational Biomedicine, Institute of Neuroscience and Medicine (INM-9)/Instute for advanced simulations (IAS-5)Forschungszentrum Juelich 52425 Jülich Germany
- Jülich Supercomputing Centre (JSC)Forschungszentrum Jülich 52425 Jülich Germany
- Department of Hematology, Oncology, Hemostaseology and Stem Cell Transplantation University Hospital AachenRWTH Aachen University Pauwelsstraße 30 52074 Aachen Germany
| |
Collapse
|
14
|
A genetic association study of glutamine-encoding DNA sequence structures, somatic CAG expansion, and DNA repair gene variants, with Huntington disease clinical outcomes. EBioMedicine 2019; 48:568-580. [PMID: 31607598 PMCID: PMC6838430 DOI: 10.1016/j.ebiom.2019.09.020] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 09/11/2019] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Huntington disease (HD) is caused by an unstable CAG/CAA repeat expansion encoding a toxic polyglutamine tract. Here, we tested the hypotheses that HD outcomes are impacted by somatic expansion of, and polymorphisms within, the HTT CAG/CAA glutamine-encoding repeat, and DNA repair genes. METHODS The sequence of the glutamine-encoding repeat and the proportion of somatic CAG expansions in blood DNA from participants inheriting 40 to 50 CAG repeats within the TRACK-HD and Enroll-HD cohorts were determined using high-throughput ultra-deep-sequencing. Candidate gene polymorphisms were genotyped using kompetitive allele-specific PCR (KASP). Genotypic associations were assessed using time-to-event and regression analyses. FINDINGS Using data from 203 TRACK-HD and 531 Enroll-HD participants, we show that individuals with higher blood DNA somatic CAG repeat expansion scores have worse HD outcomes: a one-unit increase in somatic expansion score was associated with a Cox hazard ratio for motor onset of 3·05 (95% CI = 1·94 to 4·80, p = 1·3 × 10-6). We also show that individual-specific somatic expansion scores are associated with variants in FAN1 (pFDR = 4·8 × 10-6), MLH3 (pFDR = 8·0 × 10-4), MLH1 (pFDR = 0·004) and MSH3 (pFDR = 0·009). We also show that HD outcomes are best predicted by the number of pure CAGs rather than total encoded-glutamines. INTERPRETATION These data establish pure CAG length, rather than encoded-glutamine, as the key inherited determinant of downstream pathophysiology. These findings have implications for HD diagnostics, and support somatic expansion as a mechanistic link for genetic modifiers of clinical outcomes, a driver of disease, and potential therapeutic target in HD and related repeat expansion disorders. FUNDING CHDI Foundation.
Collapse
|
15
|
van Cruchten RTP, Wieringa B, Wansink DG. Expanded CUG repeats in DMPK transcripts adopt diverse hairpin conformations without influencing the structure of the flanking sequences. RNA (NEW YORK, N.Y.) 2019; 25:481-495. [PMID: 30700578 PMCID: PMC6426290 DOI: 10.1261/rna.068940.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Myotonic dystrophy type 1 (DM1) is a complex neuromuscular disorder caused by expansion of a CTG repeat in the 3'-untranslated region (UTR) of the DMPK gene. Mutant DMPK transcripts form aberrant structures and anomalously associate with RNA-binding proteins (RBPs). As a first step toward better understanding of the involvement of abnormal DMPK mRNA folding in DM1 manifestation, we used SHAPE, DMS, CMCT, and RNase T1 structure probing in vitro for modeling of the topology of the DMPK 3'-UTR with normal and pathogenic repeat lengths of up to 197 CUG triplets. The resulting structural information was validated by disruption of base-pairing with LNA antisense oligonucleotides (AONs) and used for prediction of therapeutic AON accessibility and verification of DMPK knockdown efficacy in cells. Our model for DMPK RNA structure demonstrates that the hairpin formed by the CUG repeat has length-dependent conformational plasticity, with a structure that is guided by and embedded in an otherwise rigid architecture of flanking regions in the DMPK 3'-UTR. Evidence is provided that long CUG repeats may form not only single asymmetrical hairpins but also exist as branched structures. These newly identified structures have implications for DM1 pathogenic mechanisms, like sequestration of RBPs and repeat-associated non-AUG (RAN) translation.
Collapse
Affiliation(s)
- Remco T P van Cruchten
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, 6525 GA, The Netherlands
| |
Collapse
|
16
|
Schilling J, Broemer M, Atanassov I, Duernberger Y, Vorberg I, Dieterich C, Dagane A, Dittmar G, Wanker E, van Roon-Mom W, Winter J, Krauß S. Deregulated Splicing Is a Major Mechanism of RNA-Induced Toxicity in Huntington's Disease. J Mol Biol 2019; 431:1869-1877. [PMID: 30711541 DOI: 10.1016/j.jmb.2019.01.034] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 12/20/2022]
Abstract
Huntington's disease (HD) is caused by an expanded CAG repeat in the huntingtin (HTT) gene, translating into an elongated polyglutamine stretch. In addition to the neurotoxic mutant HTT protein, the mutant CAG repeat RNA can exert toxic functions by trapping RNA-binding proteins. While few examples of proteins that aberrantly bind to mutant HTT RNA and execute abnormal function in conjunction with the CAG repeat RNA have been described, an unbiased approach to identify the interactome of mutant HTT RNA is missing. Here, we describe the analysis of proteins that preferentially bind mutant HTT RNA using a mass spectrometry approach. We show that (I) the majority of proteins captured by mutant HTT RNA belong to the spliceosome pathway, (II) expression of mutant CAG repeat RNA induces mis-splicing in a HD cell model, (III) overexpression of one of the splice factors trapped by mutant HTT ameliorates the HD phenotype in a fly model and (VI) deregulated splicing occurs in human HD brain. Our data suggest that deregulated splicing is a prominent mechanism of RNA-induced toxicity in HD.
Collapse
Affiliation(s)
- Judith Schilling
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, North Rhine-Westphalia, Germany
| | - Meike Broemer
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, North Rhine-Westphalia, Germany
| | - Ilian Atanassov
- Max Planck Institute for Biology of Ageing, 50931 Cologne, North Rhine-Westphalia, Germany
| | - Yvonne Duernberger
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, North Rhine-Westphalia, Germany
| | - Ina Vorberg
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, North Rhine-Westphalia, Germany; Department of Neurology, Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, North Rhine-Westphalia, Germany
| | - Christoph Dieterich
- Max Planck Institute for Biology of Ageing, 50931 Cologne, North Rhine-Westphalia, Germany
| | - Alina Dagane
- Max-Delbrück-Center for Molecular Medicine (MDC), 13092 Berlin, Germany
| | - Gunnar Dittmar
- Max-Delbrück-Center for Molecular Medicine (MDC), 13092 Berlin, Germany; Luxembourg Institute of Health, 1445 Strassen, Luxembourg
| | - Erich Wanker
- Max-Delbrück-Center for Molecular Medicine (MDC), 13092 Berlin, Germany
| | | | - Jennifer Winter
- Institute of Human Genetics, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Rhineland-Palatinate, Germany
| | - Sybille Krauß
- German Center for Neurodegenerative Diseases (DZNE), 53127, Bonn, North Rhine-Westphalia, Germany.
| |
Collapse
|
17
|
Thadke SA, Perera JDR, Hridya VM, Bhatt K, Shaikh AY, Hsieh WC, Chen M, Gayathri C, Gil RR, Rule GS, Mukherjee A, Thornton CA, Ly DH. Design of Bivalent Nucleic Acid Ligands for Recognition of RNA-Repeated Expansion Associated with Huntington's Disease. Biochemistry 2018; 57:2094-2108. [PMID: 29562132 PMCID: PMC6091552 DOI: 10.1021/acs.biochem.8b00062] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We report the development of a new class of nucleic acid ligands that is comprised of Janus bases and the MPγPNA backbone and is capable of binding rCAG repeats in a sequence-specific and selective manner via, inference, bivalent H-bonding interactions. Individually, the interactions between ligands and RNA are weak and transient. However, upon the installation of a C-terminal thioester and an N-terminal cystine and the reduction of disulfide bond, they undergo template-directed native chemical ligation to form concatenated oligomeric products that bind tightly to the RNA template. In the absence of an RNA target, they self-deactivate by undergoing an intramolecular reaction to form cyclic products, rendering them inactive for further binding. The work has implications for the design of ultrashort nucleic acid ligands for targeting rCAG-repeat expansion associated with Huntington's disease and a number of other related neuromuscular and neurodegenerative disorders.
Collapse
Affiliation(s)
- Shivaji A. Thadke
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - J. Dinithi R. Perera
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - V. M. Hridya
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra 411008, India
| | - Kirti Bhatt
- Department of Neurology, Box 645, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Ashif Y. Shaikh
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Wei-Che Hsieh
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Mengshen Chen
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Chakicherla Gayathri
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Roberto R. Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Gordon S. Rule
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Arnab Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra 411008, India
| | - Charles A. Thornton
- Department of Neurology, Box 645, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Danith H. Ly
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| |
Collapse
|
18
|
Guo P, Chan HYE, Lam SL. Conformational flexibility in the RNA stem-loop structures formed by CAG repeats. FEBS Lett 2017; 591:1752-1760. [PMID: 28488797 DOI: 10.1002/1873-3468.12672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/28/2017] [Accepted: 05/05/2017] [Indexed: 11/11/2022]
Abstract
The expansion of CAG repeats has been found to be associated with at least nine human genetic disorders. In these disorders, the full-length expanded CAG RNA transcripts are cleaved into small CAG-repeated RNAs which are cytotoxic and known to be capable of forming hairpins. To better understand the RNA pathogenic mechanism, in this study we have performed high-resolution nuclear magnetic resonance structural investigations on the RNA hairpins formed by CAG repeats. Our results show the formation of a type III AGCA tetraloop and reveal the effect of stem rigidity on the loop conformational flexibility.
Collapse
Affiliation(s)
- Pei Guo
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Ho Yin Edwin Chan
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong.,Gerald Choa Neuroscience Centre, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Sik Lok Lam
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| |
Collapse
|
19
|
Ciesiolka A, Jazurek M, Drazkowska K, Krzyzosiak WJ. Structural Characteristics of Simple RNA Repeats Associated with Disease and their Deleterious Protein Interactions. Front Cell Neurosci 2017; 11:97. [PMID: 28442996 PMCID: PMC5387085 DOI: 10.3389/fncel.2017.00097] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/21/2017] [Indexed: 12/14/2022] Open
Abstract
Short Tandem Repeats (STRs) are frequent entities in many transcripts, however, in some cases, pathological events occur when a critical repeat length is reached. This phenomenon is observed in various neurological disorders, such as myotonic dystrophy type 1 (DM1), fragile X-associated tremor/ataxia syndrome, C9orf72-related amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD), and polyglutamine diseases, such as Huntington's disease (HD) and spinocerebellar ataxias (SCA). The pathological effects of these repeats are triggered by mutant RNA transcripts and/or encoded mutant proteins, which depend on the localization of the expanded repeats in non-coding or coding regions. A growing body of recent evidence revealed that the RNA structures formed by these mutant RNA repeat tracts exhibit toxic effects on cells. Therefore, in this review article, we present existing knowledge on the structural aspects of different RNA repeat tracts as revealed mainly using well-established biochemical and biophysical methods. Furthermore, in several cases, it was shown that these expanded RNA structures are potent traps for a variety of RNA-binding proteins and that the sequestration of these proteins from their normal intracellular environment causes alternative splicing aberration, inhibition of nuclear transport and export, or alteration of a microRNA biogenesis pathway. Therefore, in this review article, we also present the most studied examples of abnormal interactions that occur between mutant RNAs and their associated proteins.
Collapse
Affiliation(s)
- Adam Ciesiolka
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of SciencesPoznan, Poland
| | - Magdalena Jazurek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of SciencesPoznan, Poland
| | - Karolina Drazkowska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of SciencesPoznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of SciencesPoznan, Poland
| |
Collapse
|
20
|
Datson NA, González-Barriga A, Kourkouta E, Weij R, van de Giessen J, Mulders S, Kontkanen O, Heikkinen T, Lehtimäki K, van Deutekom JCT. The expanded CAG repeat in the huntingtin gene as target for therapeutic RNA modulation throughout the HD mouse brain. PLoS One 2017; 12:e0171127. [PMID: 28182673 PMCID: PMC5300196 DOI: 10.1371/journal.pone.0171127] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 01/16/2017] [Indexed: 01/11/2023] Open
Abstract
The aim of these studies was to demonstrate the therapeutic capacity of an antisense oligonucleotide with the sequence (CUG)7 targeting the expanded CAG repeat in huntingtin (HTT) mRNA in vivo in the R6/2 N-terminal fragment and Q175 knock-in Huntington’s disease (HD) mouse models. In a first study, R6/2 mice received six weekly intracerebroventricular infusions with a low and high dose of (CUG)7 and were sacrificed 2 weeks later. A 15–60% reduction of both soluble and aggregated mutant HTT protein was observed in striatum, hippocampus and cortex of (CUG)7-treated mice. This correction at the molecular level resulted in an improvement of performance in multiple motor tasks, increased whole brain and cortical volume, reduced levels of the gliosis marker myo-inositol, increased levels of the neuronal integrity marker N-aceyl aspartate and increased mRNA levels of the striatal marker Darpp-32. These neuroanatomical and neurochemical changes, together with the improved motor performance, suggest that treatment with (CUG)7 ameliorates basal ganglia dysfunction. The HTT-lowering was confirmed by an independent study in Q175 mice using a similar (CUG)7 AON dosing regimen, further demonstrating a lasting reduction of mutant HTT protein in striatum, hippocampus and cortex for up to 18 weeks post last infusion along with an increase in motor activity. Based on these encouraging results, (CUG)7 may thus offer an interesting alternative HTT-lowering strategy for HD.
Collapse
Affiliation(s)
| | | | | | - Rudie Weij
- BioMarin Nederland BV, Leiden, The Netherlands
| | | | | | - Outi Kontkanen
- Charles River Discovery Research Services, Kuopio, Finland
| | | | | | | |
Collapse
|
21
|
Błaszczyk L, Rypniewski W, Kiliszek A. Structures of RNA repeats associated with neurological diseases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28130835 DOI: 10.1002/wrna.1412] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 10/25/2016] [Accepted: 11/12/2016] [Indexed: 01/04/2023]
Abstract
All RNA molecules possess a 'propensity' to fold into complex secondary and tertiary structures. Although they are composed of only four types of nucleotides, they show an enormous structural richness which reflects their diverse functions in the cell. However, in some cases the folding of RNA can have deleterious consequences. Aberrantly expanded, repeated RNA sequences can exhibit gain-of-function abnormalities and become pathogenic, giving rise to many incurable neurological diseases. Most RNA repeats form long hairpin structures whose stem consists of noncanonical base pairs interspersed among Watson-Crick pairs. The expanded hairpins have an ability to sequester important proteins and form insoluble nuclear foci. The RNA pathology, common to many repeat disorders, has drawn attention to the structures of the RNA repeats. In this review, we summarize secondary structure probing and crystallographic studies of disease-related RNA repeat sequences. We discuss the unique structural features which can contribute to the pathogenic properties of the repeated runs. In addition, we present the newest reports concerning structural data linked to therapeutic approaches. WIREs RNA 2017, 8:e1412. doi: 10.1002/wrna.1412 For further resources related to this article, please visit the WIREs website.
Collapse
Affiliation(s)
- Leszek Błaszczyk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Wojciech Rypniewski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Agnieszka Kiliszek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| |
Collapse
|
22
|
Griesche N, Schilling J, Weber S, Rohm M, Pesch V, Matthes F, Auburger G, Krauss S. Regulation of mRNA Translation by MID1: A Common Mechanism of Expanded CAG Repeat RNAs. Front Cell Neurosci 2016; 10:226. [PMID: 27774050 PMCID: PMC5054010 DOI: 10.3389/fncel.2016.00226] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 09/20/2016] [Indexed: 12/28/2022] Open
Abstract
Expansion of CAG repeats, which code for the disease-causing polyglutamine protein, is a common feature in polyglutamine diseases. RNA-mediated mechanisms that contribute to neuropathology in polyglutamine diseases are important. RNA-toxicity describes a phenomenon by which the mutant CAG repeat RNA recruits RNA-binding proteins, thereby leading to aberrant function. For example the MID1 protein binds to mutant huntingtin (HTT) RNA, which is linked to Huntington's disease (HD), at its CAG repeat region and induces protein synthesis of mutant protein. But is this mechanism specific to HD or is it a common mechanism in CAG repeat expansion disorders? To answer this question, we have analyzed the interaction between MID1 and three other CAG repeat mRNAs, Ataxin2 (ATXN2), Ataxin3 (ATXN3), and Ataxin7 (ATXN7), that all differ in the sequence flanking the CAG repeat. We show that ATXN2, ATXN3, and ATXN7 bind to MID1 in a CAG repeat length-dependent manner. Furthermore, we show that functionally, in line with what we have previously observed for HTT, the binding of MID1 to ATXN2, ATXN3, and ATXN7 mRNA induces protein synthesis in a repeat length-dependent manner. Our data suggest that regulation of protein translation by the MID1 complex is a common mechanism for CAG repeat containing mRNAs.
Collapse
Affiliation(s)
| | | | | | - Marlena Rohm
- German Center for Neurodegenerative Diseases Bonn, Germany
| | - Verena Pesch
- German Center for Neurodegenerative Diseases Bonn, Germany
| | - Frank Matthes
- German Center for Neurodegenerative Diseases Bonn, Germany
| | - Georg Auburger
- Experimental Neurology, Goethe University Medical School Frankfurt, Germany
| | - Sybille Krauss
- German Center for Neurodegenerative Diseases Bonn, Germany
| |
Collapse
|
23
|
Kim SH, Shahani N, Bae BI, Sbodio JI, Chung Y, Nakaso K, Paul BD, Sawa A. Allele-specific regulation of mutant Huntingtin by Wig1, a downstream target of p53. Hum Mol Genet 2016; 25:2514-2524. [PMID: 27206983 DOI: 10.1093/hmg/ddw115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 03/15/2016] [Accepted: 04/11/2016] [Indexed: 02/07/2023] Open
Abstract
p53 has been implicated in the pathophysiology of Huntington's disease (HD). Nonetheless, the molecular mechanism of how p53 may play a unique role in the pathology remains elusive. To address this question at the molecular and cellular biology levels, we initially screened differentially expressed molecules specifically dependent on p53 in a HD animal model. Among the candidate molecules, wild-type p53-induced gene 1 (Wig1) is markedly upregulated in the cerebral cortex of HD patients. Wig1 preferentially upregulates the level of mutant Huntingtin (Htt) compared with wild-type Htt. This allele-specific characteristic of Wig1 is likely to be explained by higher affinity binding to mutant Htt transcripts than normal counterpart for the stabilization. Knockdown of Wig1 level significantly ameliorates mutant Htt-elicited cytotoxicity and aggregate formation. Together, we propose that Wig1, a key p53 downstream molecule in HD condition, play an important role in stabilizing mutant Htt mRNA and thereby accelerating HD pathology in the mHtt-p53-Wig1 positive feedback manner.
Collapse
Affiliation(s)
- Sun-Hong Kim
- Department of Psychiatry and Behavioral Sciences
| | | | - Byoung-Ii Bae
- Neuroscience Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Juan I Sbodio
- Neuroscience Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Youjin Chung
- Department of Psychiatry and Behavioral Sciences
| | - Kazuhiro Nakaso
- Division of Medical Biochemistry, Department of Pathophysiological and Therapeutic Science, Tottori University Faculty of Medicine, 86, Nishicho, Yonago, 683-8503, Japan
| | - Bindu D Paul
- Neuroscience Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Akira Sawa
- Department of Psychiatry and Behavioral Sciences, .,Neuroscience Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| |
Collapse
|
24
|
Cugusi S, Li Y, Jin P, Lucchesi JC. The Drosophila Helicase MLE Targets Hairpin Structures in Genomic Transcripts. PLoS Genet 2016; 12:e1005761. [PMID: 26752049 PMCID: PMC4710571 DOI: 10.1371/journal.pgen.1005761] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 12/02/2015] [Indexed: 12/28/2022] Open
Abstract
RNA hairpins are a common type of secondary structures that play a role in every aspect of RNA biochemistry including RNA editing, mRNA stability, localization and translation of transcripts, and in the activation of the RNA interference (RNAi) and microRNA (miRNA) pathways. Participation in these functions often requires restructuring the RNA molecules by the association of single-strand (ss) RNA-binding proteins or by the action of helicases. The Drosophila MLE helicase has long been identified as a member of the MSL complex responsible for dosage compensation. The complex includes one of two long non-coding RNAs and MLE was shown to remodel the roX RNA hairpin structures in order to initiate assembly of the complex. Here we report that this function of MLE may apply to the hairpins present in the primary RNA transcripts that generate the small molecules responsible for RNA interference. Using stocks from the Transgenic RNAi Project and the Vienna Drosophila Research Center, we show that MLE specifically targets hairpin RNAs at their site of transcription. The association of MLE at these sites is independent of sequence and chromosome location. We use two functional assays to test the biological relevance of this association and determine that MLE participates in the RNAi pathway.
Collapse
Affiliation(s)
- Simona Cugusi
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
| | - Yujing Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta
| | - Peng Jin
- Department of Human Genetics, Emory University School of Medicine, Atlanta
| | - John C. Lucchesi
- Department of Biology, Emory University, Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
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.
Collapse
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
| |
Collapse
|