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Cattaneo E, Scalzo D, Zobel M, Iennaco R, Maffezzini C, Besusso D, Maestri S. When repetita no-longer iuvant: somatic instability of the CAG triplet in Huntington's disease. Nucleic Acids Res 2025; 53:gkae1204. [PMID: 39673793 PMCID: PMC11724284 DOI: 10.1093/nar/gkae1204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2024] [Revised: 11/08/2024] [Accepted: 12/02/2024] [Indexed: 12/16/2024] Open
Abstract
Trinucleotide repeats in DNA exhibit a dual nature due to their inherent instability. While their rapid expansion can diversify gene expression during evolution, exceeding a certain threshold can lead to diseases such as Huntington's disease (HD), a neurodegenerative condition, triggered by >36 C-A-G repeats in exon 1 of the Huntingtin gene. Notably, the discovery of somatic instability (SI) of the tract allows these mutations, inherited from an affected parent, to further expand throughout the patient's lifetime, resulting in a mosaic brain with specific neurons exhibiting variable and often extreme CAG lengths, ultimately leading to their death. Genome-wide association studies have identified genetic variants-both cis and trans, including mismatch repair modifiers-that modulate SI, as shown in blood cells, and influence HD's age of onset. This review will explore the evidence for SI in HD and its role in disease pathogenesis, as well as the therapeutic implications of these findings. We conclude by emphasizing the urgent need for reliable methods to quantify SI for diagnostic and prognostic purposes.
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Affiliation(s)
- Elena Cattaneo
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
| | - Davide Scalzo
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
| | - Martina Zobel
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
| | - Raffaele Iennaco
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
| | - Camilla Maffezzini
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
| | - Dario Besusso
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
| | - Simone Maestri
- Department of Biosciences, University of Milan, street Giovanni Celoria, 26, 20133, Milan, Italy
- INGM, Fondazione Istituto Nazionale Genetica Molecolare ‘Romeo ed Enrica Invernizzi’, street Francesco Sforza, 35, 20122, Milan, Italy
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Nguyen TB, Miramontes R, Chillon-Marinas C, Maimon R, Vazquez-Sanchez S, Lau AL, McClure NR, Wu Z, Wang KQ, England WE, Singha M, Stocksdale JT, Heath M, Jang KH, Jung S, Ling K, Jafar-Nejad P, McKnight JI, Ho LN, Dalahmah OA, Faull RLM, Steffan JS, Reidling JC, Jang C, Lee G, Cleveland DW, Lagier-Tourenne C, Spitale RC, Thompson LM. Aberrant splicing in Huntington's disease accompanies disrupted TDP-43 activity and altered m6A RNA modification. Nat Neurosci 2025:10.1038/s41593-024-01850-w. [PMID: 39762660 DOI: 10.1038/s41593-024-01850-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 11/14/2024] [Indexed: 01/15/2025]
Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion in the HTT gene, leading to altered gene expression. However, the mechanisms leading to disrupted RNA processing in HD remain unclear. Here we identify TDP-43 and the N6-methyladenosine (m6A) writer protein METTL3 to be upstream regulators of exon skipping in multiple HD systems. Disrupted nuclear localization of TDP-43 and cytoplasmic accumulation of phosphorylated TDP-43 occurs in HD mouse and human brains, with TDP-43 also co-localizing with HTT nuclear aggregate-like bodies distinct from mutant HTT inclusions. The binding of TDP-43 onto RNAs encoding HD-associated differentially expressed and aberrantly spliced genes is decreased. Finally, m6A RNA modification is reduced on RNAs abnormally expressed in the striatum of HD R6/2 mouse brain, including at clustered sites adjacent to TDP-43 binding sites. Our evidence supports TDP-43 loss of function coupled with altered m6A modification as a mechanism underlying alternative splicing in HD.
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Affiliation(s)
- Thai B Nguyen
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | | | - Carlos Chillon-Marinas
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Roy Maimon
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Sonia Vazquez-Sanchez
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Alice L Lau
- Department of Psychiatry & Human Behavior, University of California, Irvine, Irvine, CA, USA
| | - Nicolette R McClure
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | - Zhuoxing Wu
- Department of Biological Chemistry, Chao Family Comprehensive Cancer Center, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Keona Q Wang
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | - Whitney E England
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA
| | - Monika Singha
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA
| | - Jennifer T Stocksdale
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | - Marie Heath
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | - Ki-Hong Jang
- Department of Microbiology and Molecular Genetics, Chao Family Comprehensive Cancer Center, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Sunhee Jung
- Department of Biological Chemistry, Chao Family Comprehensive Cancer Center, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Karen Ling
- Ionis Pharmaceuticals, Inc., Carlsbad, CA, USA
| | | | - Jharrayne I McKnight
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | - Leanne N Ho
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA
| | - Osama Al Dalahmah
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Richard L M Faull
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
| | - Joan S Steffan
- Department of Psychiatry & Human Behavior, University of California, Irvine, Irvine, CA, USA
| | | | - Cholsoon Jang
- Department of Biological Chemistry, Chao Family Comprehensive Cancer Center, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Gina Lee
- Department of Microbiology and Molecular Genetics, Chao Family Comprehensive Cancer Center, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Don W Cleveland
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Clotilde Lagier-Tourenne
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard University and MIT, Cambridge, MA, USA
| | - Robert C Spitale
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA.
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA.
| | - Leslie M Thompson
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA, USA.
- UCI MIND, University of California, Irvine, Irvine, CA, USA.
- Department of Psychiatry & Human Behavior, University of California, Irvine, Irvine, CA, USA.
- Sue and Bill Gross Stem Cell Center, University of California, Irvine, Irvine, CA, USA.
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3
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Zhang Y, Liu X, Li Z, Li H, Miao Z, Wan B, Xu X. Advances on the Mechanisms and Therapeutic Strategies in Non-coding CGG Repeat Expansion Diseases. Mol Neurobiol 2024; 61:10722-10735. [PMID: 38780719 DOI: 10.1007/s12035-024-04239-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/02/2024] [Indexed: 05/25/2024]
Abstract
Non-coding CGG repeat expansions within the 5' untranslated region are implicated in a range of neurological disorders, including fragile X-associated tremor/ataxia syndrome, oculopharyngeal myopathy with leukodystrophy, and oculopharyngodistal myopathy. This review outlined the general characteristics of diseases associated with non-coding CGG repeat expansions, detailing their clinical manifestations and neuroimaging patterns, which often overlap and indicate shared pathophysiological traits. We summarized the underlying molecular mechanisms of these disorders, providing new insights into the roles that DNA, RNA, and toxic proteins play. Understanding these mechanisms is crucial for the development of targeted therapeutic strategies. These strategies include a range of approaches, such as antisense oligonucleotides, RNA interference, genomic DNA editing, small molecule interventions, and other treatments aimed at correcting the dysregulated processes inherent in these disorders. A deeper understanding of the shared mechanisms among non-coding CGG repeat expansion disorders may hold the potential to catalyze the development of innovative therapies, ultimately offering relief to individuals grappling with these debilitating neurological conditions.
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Affiliation(s)
- Yutong Zhang
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Xuan Liu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Zeheng Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
| | - Hao Li
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China
- Department of Neurology, The Fourth Affiliated Hospital of Soochow University, Suzhou, 215124, China
| | - Zhigang Miao
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Bo Wan
- The Institute of Neuroscience, Soochow University, Suzhou City, China
| | - Xingshun Xu
- Departments of Neurology, The First Affiliated Hospital of Soochow University, Suzhou City, China.
- The Institute of Neuroscience, Soochow University, Suzhou City, China.
- Department of Neurology, The First Affiliated Hospital of Soochow University, Suzhou, 215000, China.
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Tu H, Yeo XY, Zhang ZW, Zhou W, Tan JY, Chi L, Chia SY, Li Z, Sim AY, Singh BK, Ma D, Zhou Z, Bonne I, Ling SC, Ng ASL, Jung S, Tan EK, Zeng L. NOTCH2NLC GGC intermediate repeat with serine induces hypermyelination and early Parkinson's disease-like phenotypes in mice. Mol Neurodegener 2024; 19:91. [PMID: 39609868 PMCID: PMC11603791 DOI: 10.1186/s13024-024-00780-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 11/13/2024] [Indexed: 11/30/2024] Open
Abstract
BACKGROUND The expansion of GGC repeats (typically exceeding 60 repeats) in the 5' untranslated region (UTR) of the NOTCH2NLC gene (N2C) is linked to N2C-related repeat expansion disorders (NREDs), such as neuronal intranuclear inclusion disease (NIID), frontotemporal dementia (FTD), essential tremor (ET), and Parkinson's disease (PD). These disorders share common clinical manifestations, including parkinsonism, dementia, seizures, and muscle weakness. Intermediate repeat sizes ranging from 40 to 60 GGC repeats, particularly those with AGC-encoded serine insertions, have been reported to be associated with PD; however, the functional implications of these intermediate repeats with serine insertion remain unexplored. METHODS Here, we utilized cellular models harbouring different sizes of N2C variant 2 (N2C2) GGC repeat expansion and CRISPR-Cas9 engineered transgenic mouse models carrying N2C2 GGC intermediate repeats with and without serine insertion to elucidate the underlying pathophysiology associated with N2C intermediate repeat with serine insertion in NREDs. RESULTS Our findings revealed that the N2C2 GGC intermediate repeat with serine insertion (32G13S) led to mitochondrial dysfunction and cell death in vitro. The neurotoxicity was influenced by the length of the repeat and was exacerbated by the presence of the serine insertion. In 12-month-old transgenic mice, 32G13S intensified intranuclear aggregation and exhibited early PD-like characteristics, including the formation of α-synuclein fibers in the midbrain and the loss of tyrosine hydroxylase (TH)-positive neurons in both the cortex and striatum. Additionally, 32G13S induced neuronal hyperexcitability and caused locomotor behavioural impairments. Transcriptomic analysis of the mouse cortex indicated dysregulation in calcium signaling and MAPK signaling pathways, both of which are critical for mitochondrial function. Notably, genes associated with myelin sheath components, including MBP and MOG, were dysregulated in the 32G13S mouse. Further investigations using immunostaining and transmission electron microscopy revealed that the N2C intermediate repeat with serine induced mitochondrial dysfunction-related hypermyelination in the cortex. CONCLUSIONS Our in vitro and in vivo investigations provide the first evidence that the N2C-GGC intermediate repeat with serine promotes intranuclear aggregation of N2C, leading to mitochondrial dysfunction-associated hypermyelination and neuronal hyperexcitability. These changes contribute to motor deficits in early PD-like neurodegeneration in NREDs.
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Affiliation(s)
- Haitao Tu
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Xin Yi Yeo
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore
| | - Zhi-Wei Zhang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Wei Zhou
- Research Department, National Neuroscience Institute, Singapore General Hospital (SGH) Campus, Singapore, 169856, Singapore
| | - Jayne Yi Tan
- Department of Neurology, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Li Chi
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Institute of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, China
| | - Sook-Yoong Chia
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Zhihong Li
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore
| | - Aik Yong Sim
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117549, Singapore
| | - Brijesh Kumar Singh
- Laboratory of Hormonal Regulation, Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Dongrui Ma
- Department of Neurology, Singapore General Hospital, Singapore, 169609, Singapore
| | - Zhidong Zhou
- Research Department, National Neuroscience Institute, Singapore General Hospital (SGH) Campus, Singapore, 169856, Singapore
- Neuroscience & Behavioural Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore
| | - Isabelle Bonne
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117549, Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
- Immunology Translational Research Programme, Life Sciences Institute, National University of Singapore, Singapore, 117456, Singapore
| | - Shuo-Chien Ling
- Neuroscience & Behavioural Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore
| | - Adeline S L Ng
- Department of Neurology, National Neuroscience Institute, Singapore, 308433, Singapore
- Neuroscience & Behavioural Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore
| | - Sangyong Jung
- Department of Medical Science, College of Medicine, CHA University, Seongnam, 13488, Republic of Korea
| | - Eng-King Tan
- Research Department, National Neuroscience Institute, Singapore General Hospital (SGH) Campus, Singapore, 169856, Singapore.
- Department of Neurology, National Neuroscience Institute, Singapore, 308433, Singapore.
- Neuroscience & Behavioural Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore.
| | - Li Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, 308433, Singapore.
- Neuroscience & Behavioural Disorders Program, DUKE-NUS Graduate Medical School, Singapore, 169857, Singapore.
- Centre for Molecular Neuropathology, Lee Kong Chian School of Medicine, Nanyang Technology University, Singapore, Novena Campus, 308232, Singapore.
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5
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Provasek VE, Bacolla A, Rangaswamy S, Mitra J, Kodavati M, Yusuf IO, Malojirao VH, Vasquez V, Britz GW, Li GM, Xu Z, Mitra S, Garruto RM, Tainer JA, Hegde ML. RNA/DNA Binding Protein TDP43 Regulates DNA Mismatch Repair Genes with Implications for Genome Stability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.16.594552. [PMID: 38798341 PMCID: PMC11118483 DOI: 10.1101/2024.05.16.594552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
TAR DNA-binding protein 43 (TDP43) is increasingly recognized for its involvement in neurodegenerative diseases, particularly amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). TDP43 proteinopathy, characterized by dysregulated nuclear export and cytoplasmic aggregation, is present in most ALS/FTD cases and is associated with a loss of nuclear function and genomic instability in neurons. Building on prior evidence linking TDP43 pathology to DNA double-strand breaks (DSBs), this study identifies a novel regulatory role for TDP43 in the DNA mismatch repair (MMR) pathway. We demonstrate that depletion or overexpression of TDP43 affects the expression of key MMR genes, including MLH1, MSH6, MSH2, MSH3, and PMS2. Specifically, TDP43 modulates the expression of MLH1 and MSH6 proteins through alternative splicing and transcript stability. These findings are validated in ALS mice models, patient-derived neural progenitor cells and autopsied brain tissues from ALS patients. Furthermore, MMR depletion showed a partial rescue of TDP43-induced DNA damage in neuronal cells. Bioinformatics analysis of TCGA cancer database reveals significant correlations between TDP43 and MMR gene expressions and mutational burden across various cancer subtypes. These results collectively establish TDP43 as a critical regulator of the MMR pathway, with broad implications for understanding the genomic instability underlying neurodegenerative and neoplastic diseases.
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Affiliation(s)
- Vincent E Provasek
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- School of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Suganya Rangaswamy
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Joy Mitra
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Manohar Kodavati
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Issa O Yusuf
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Vikas H Malojirao
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Velmarini Vasquez
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Gavin W Britz
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Neurosurgery and Department of Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zuoshang Xu
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Sankar Mitra
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Ralph M Garruto
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY 13902
| | - John A Tainer
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Muralidhar L Hegde
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
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6
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Barraza SJ, Woll MG. Pre‐mRNA Splicing Modulation. METHODS AND PRINCIPLES IN MEDICINAL CHEMISTRY 2024:151-202. [DOI: 10.1002/9783527840458.ch7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2025]
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7
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Liu T, Bao L, Wang Y. The Thermodynamic and Kinetic Properties of the dA-rU DNA-RNA Hybrid Base Pair Investigated via Molecular Dynamics Simulations. Molecules 2024; 29:4920. [PMID: 39459288 PMCID: PMC11510705 DOI: 10.3390/molecules29204920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2024] [Revised: 10/11/2024] [Accepted: 10/15/2024] [Indexed: 10/28/2024] Open
Abstract
DNA-RNA hybrid duplexes play essential roles during the reverse transcription of RNA viruses and DNA replication. The opening and conformation changes of individual base pairs are critical to their biological functions. However, the microscopic mechanisms governing base pair closing and opening at the atomic level remain poorly understood. In this study, we investigated the thermodynamic and kinetic parameters of the dA-rU base pair in a DNA-RNA hybrid duplex using 4 μs all-atom molecular dynamics (MD) simulations at different temperatures. Our results showed that the thermodynamic parameters of the dA-rU base pair aligned with the predictions of the nearest-neighbor model and were close to those of the AU base pair in RNA. The temperature dependence of the average lifetimes of both the open and the closed states, as well as the transition path times, were obtained. The free-energy barrier for a single base pair opening and closing arises from an increase in enthalpy due to the disruption of the base-stacking interactions and hydrogen bonding, along with an entropy loss attributed to the accompanying restrictions, such as torsional angle constraints and solvent viscosity.
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Affiliation(s)
- Taigang Liu
- School of Medical Engineering, Xinxiang Medical University, Xinxiang 453003, China;
| | - Lei Bao
- School of Public Health, Hubei University of Medicine, Shiyan 442000, China;
| | - Yujie Wang
- Department of Physics and Telecommunication Engineering, Zhoukou Normal University, Zhoukou 466000, China
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8
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Colicino-Murbach E, Hathaway C, Dungrawala H. Replication fork stalling in late S-phase elicits nascent strand degradation by DNA mismatch repair. Nucleic Acids Res 2024; 52:10999-11013. [PMID: 39180395 PMCID: PMC11472054 DOI: 10.1093/nar/gkae721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 07/03/2024] [Accepted: 08/06/2024] [Indexed: 08/26/2024] Open
Abstract
Eukaryotic chromosomal replication occurs in a segmented, temporal manner wherein open euchromatin and compact heterochromatin replicate during early and late S-phase respectively. Using single molecule DNA fiber analyses coupled with cell synchronization, we find that newly synthesized strands remain stable at perturbed forks in early S-phase. Unexpectedly, stalled forks are susceptible to nucleolytic digestion during late replication resulting in defective fork restart. This inherent vulnerability to nascent strand degradation is dependent on fork reversal enzymes and resection nucleases MRE11, DNA2 and EXO1. Inducing chromatin compaction elicits digestion of nascent DNA in response to fork stalling due to reduced association of RAD51 with nascent DNA. Furthermore, RAD51 occupancy at stalled forks in late S-phase is diminished indicating that densely packed chromatin limits RAD51 accessibility to mediate replication fork protection. Genetic analyses reveal that susceptibility of late replicating forks to nascent DNA digestion is dependent on EXO1 via DNA mismatch repair (MMR) and that the BRCA2-mediated replication fork protection blocks MMR from degrading nascent DNA. Overall, our findings illustrate differential regulation of fork protection between early and late replication and demonstrate nascent strand degradation as a critical determinant of heterochromatin instability in response to replication stress.
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Affiliation(s)
| | - Caitlin Hathaway
- Department of Molecular Biosciences, University of South Florida, Tampa, FL, USA
| | - Huzefa Dungrawala
- Department of Molecular Biosciences, University of South Florida, Tampa, FL, USA
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9
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Pan F, Xu P, Roland C, Sagui C, Weninger K. Structural and Dynamical Properties of Nucleic Acid Hairpins Implicated in Trinucleotide Repeat Expansion Diseases. Biomolecules 2024; 14:1278. [PMID: 39456210 PMCID: PMC11505666 DOI: 10.3390/biom14101278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2024] [Revised: 09/26/2024] [Accepted: 10/05/2024] [Indexed: 10/28/2024] Open
Abstract
Dynamic mutations in some human genes containing trinucleotide repeats are associated with severe neurodegenerative and neuromuscular disorders-known as Trinucleotide (or Triplet) Repeat Expansion Diseases (TREDs)-which arise when the repeat number of triplets expands beyond a critical threshold. While the mechanisms causing the DNA triplet expansion are complex and remain largely unknown, it is now recognized that the expandable repeats lead to the formation of nucleotide configurations with atypical structural characteristics that play a crucial role in TREDs. These nonstandard nucleic acid forms include single-stranded hairpins, Z-DNA, triplex structures, G-quartets and slipped-stranded duplexes. Of these, hairpin structures are the most prolific and are associated with the largest number of TREDs and have therefore been the focus of recent single-molecule FRET experiments and molecular dynamics investigations. Here, we review the structural and dynamical properties of nucleic acid hairpins that have emerged from these studies and the implications for repeat expansion mechanisms. The focus will be on CAG, GAC, CTG and GTC hairpins and their stems, their atomistic structures, their stability, and the important role played by structural interrupts.
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Affiliation(s)
- Feng Pan
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; (F.P.); (C.R.)
- Department of Statistics, Florida State University, Tallahassee, FL 32306, USA
| | - Pengning Xu
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; (F.P.); (C.R.)
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Christopher Roland
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; (F.P.); (C.R.)
| | - Celeste Sagui
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; (F.P.); (C.R.)
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; (F.P.); (C.R.)
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10
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Shibata T, Nakamachi A, Nakatani K. Enhancing Binding Affinity to CGG/CGG Triad: Optimizing Naphthyridine Carbamate Dimer Derivatives with Varied Linker Lengths. ChemMedChem 2024; 19:e202400351. [PMID: 38890132 DOI: 10.1002/cmdc.202400351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/13/2024] [Accepted: 06/18/2024] [Indexed: 06/20/2024]
Abstract
This study examines the binding properties of six naphthyridine carbamate dimer (NCD) derivatives with varying linker lengths to the CGG/CGG triad, a non-canonical DNA structure linked to repeat expansion disorders. By altering the linker length from 2 to 4 methylene groups, we found changes in thermal stability of the ligand-bound complexes while maintaining a consistent 2 : 1 binding stoichiometry. Among the derivatives, CC23 showed superior binding affinity compared to the parent molecule CC33 (NCD). Spectroscopic analyses revealed that linker length influences the conformational equilibrium of NCD derivatives. Thermal melting temperature measurements demonstrated CC23's enhanced thermal stability over CC33. These findings underscore the potential of optimized NCD derivatives, like CC23, as tools to modulate CGG repeat structures, offering insights for therapeutic strategies targeting repeat expansion disorders.
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Affiliation(s)
- Tomonori Shibata
- Department of Regulatory Bioorganic Chemistry, SANKEN, The University of Osaka, 8-1 Mihogaoka, Ibaraki, 567-0047, Japan
| | - Ayano Nakamachi
- Department of Regulatory Bioorganic Chemistry, SANKEN, The University of Osaka, 8-1 Mihogaoka, Ibaraki, 567-0047, Japan
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, SANKEN, The University of Osaka, 8-1 Mihogaoka, Ibaraki, 567-0047, Japan
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11
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Cadden G, Wilken S, Magennis S. A single CAA interrupt in a DNA three-way junction containing a CAG repeat hairpin results in parity-dependent trapping. Nucleic Acids Res 2024; 52:9317-9327. [PMID: 39041420 PMCID: PMC11347167 DOI: 10.1093/nar/gkae644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/04/2024] [Accepted: 07/14/2024] [Indexed: 07/24/2024] Open
Abstract
An increasing number of human disorders are attributed to genomic expansions of short tandem repeats (STRs). Secondary DNA structures formed by STRs are believed to play an important role in expansion, while the presence of nucleotide interruptions within the pure repeat sequence is known to delay the onset and progression of disease. We have used two single-molecule fluorescence techniques to analyse the structure and dynamics of DNA three-way junctions (3WJs) containing CAG repeat hairpin slipouts, with and without a single CAA interrupt. For a 3WJ with a (CAG)10 slipout, the CAA interrupt is preferentially located in the hairpin loop, and the branch migration dynamics are 4-fold slower than for the 3WJ with a pure (CAG)10, and 3-fold slower than a 3WJ with a pure (CAG)40 repeat. The (CAG)11 3WJ with CAA interrupt adopts a conformation that places the interrupt in or near the hairpin loop, with similar dynamics to the pure (CAG)10 and (CAG)11 3WJs. We have shown that changing a single nucleotide (G to A) in a pure repeat can have a large impact on 3WJ structure and dynamics, which may be important for the protective role of interrupts in repeat expansion diseases.
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Affiliation(s)
- Gillian M Cadden
- School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, UK
| | - Svea J Wilken
- School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, UK
| | - Steven W Magennis
- School of Chemistry, University of Glasgow, Joseph Black Building, University Avenue, Glasgow G12 8QQ, UK
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12
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Kojak N, Kuno J, Fittipaldi KE, Khan A, Wenger D, Glasser M, Donnianni RA, Tang Y, Zhang J, Huling K, Ally R, Mujica AO, Turner T, Magardino G, Huang PY, Kerk SY, Droguett G, Prissette M, Rojas J, Gomez T, Gagliardi A, Hunt C, Rabinowitz JS, Gong G, Poueymirou W, Chiao E, Zambrowicz B, Siao CJ, Kajimura D. Somatic and intergenerational G4C2 hexanucleotide repeat instability in a human C9orf72 knock-in mouse model. Nucleic Acids Res 2024; 52:5732-5755. [PMID: 38597682 PMCID: PMC11162798 DOI: 10.1093/nar/gkae250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/11/2024] Open
Abstract
Expansion of a G4C2 repeat in the C9orf72 gene is associated with familial Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). To investigate the underlying mechanisms of repeat instability, which occurs both somatically and intergenerationally, we created a novel mouse model of familial ALS/FTD that harbors 96 copies of G4C2 repeats at a humanized C9orf72 locus. In mouse embryonic stem cells, we observed two modes of repeat expansion. First, we noted minor increases in repeat length per expansion event, which was dependent on a mismatch repair pathway protein Msh2. Second, we found major increases in repeat length per event when a DNA double- or single-strand break (DSB/SSB) was artificially introduced proximal to the repeats, and which was dependent on the homology-directed repair (HDR) pathway. In mice, the first mode primarily drove somatic repeat expansion. Major changes in repeat length, including expansion, were observed when SSB was introduced in one-cell embryos, or intergenerationally without DSB/SSB introduction if G4C2 repeats exceeded 400 copies, although spontaneous HDR-mediated expansion has yet to be identified. These findings provide a novel strategy to model repeat expansion in a non-human genome and offer insights into the mechanism behind C9orf72 G4C2 repeat instability.
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Affiliation(s)
- Nada Kojak
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Junko Kuno
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - David Wenger
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - Yajun Tang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Jade Zhang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Katie Huling
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Roxanne Ally
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | | | - Pei Yi Huang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Sze Yen Kerk
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - Jose Rojas
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | | | | | - Guochun Gong
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Eric Chiao
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
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13
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Martinsen E, Jinnurine T, Subramani S, Rogne M. Advances in RNA therapeutics for modulation of 'undruggable' targets. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2024; 204:249-294. [PMID: 38458740 DOI: 10.1016/bs.pmbts.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Over the past decades, drug discovery utilizing small pharmacological compounds, fragment-based therapeutics, and antibody therapy have significantly advanced treatment options for many human diseases. However, a major bottleneck has been that>70% of human proteins/genomic regions are 'undruggable' by the above-mentioned approaches. Many of these proteins constitute essential drug targets against complex multifactorial diseases like cancer, immunological disorders, and neurological diseases. Therefore, alternative approaches are required to target these proteins or genomic regions in human cells. RNA therapeutics is a promising approach for many of the traditionally 'undruggable' targets by utilizing methods such as antisense oligonucleotides, RNA interference, CRISPR/Cas-based genome editing, aptamers, and the development of mRNA therapeutics. In the following chapter, we will put emphasis on recent advancements utilizing these approaches against challenging drug targets, such as intranuclear proteins, intrinsically disordered proteins, untranslated genomic regions, and targets expressed in inaccessible tissues.
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Affiliation(s)
| | | | - Saranya Subramani
- Pioneer Research AS, Oslo Science Park, Oslo, Norway; Department of Pharmacy, Section for Pharmacology and Pharmaceutical Biosciences, University of Oslo, Oslo, Norway
| | - Marie Rogne
- Pioneer Research AS, Oslo Science Park, Oslo, Norway; Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway.
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14
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Li J, Wang H, Yang W. Tandem MutSβ binding to long extruded DNA trinucleotide repeats underpins pathogenic expansions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.12.571350. [PMID: 38168405 PMCID: PMC10760016 DOI: 10.1101/2023.12.12.571350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Expansion of trinucleotide repeats causes Huntington's disease, Fragile X syndrome and over twenty other monogenic disorders1. How mismatch repair protein MutSβ and large repeats of CNG (N=A, T, C or G) cooperate to drive the expansion is poorly understood. Contrary to expectations, we find that MutSβ prefers to bind the stem of an extruded (CNG) hairpin rather than the hairpin end or hairpin-duplex junction. Structural analyses reveal that in the presence of MutSβ, CNG repeats with N:N mismatches adopt a B form-like pseudo-duplex, with one or two CNG repeats slipped out forming uneven bubbles that partly mimic insertion-deletion loops of mismatched DNA2. When the extruded hairpin exceeds 40-45 repeats, it can be bound by three or more MutSβ molecules, which are resistant to ATP-dependent dissociation. We envision that such MutSβ-CNG complexes recruit MutLγ endonuclease to nick DNA and initiate the repeat expansion process3,4. To develop drugs against the expansion diseases, we have identified lead compounds that prevent MutSβ binding to CNG repeats but not to mismatched DNA.
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Affiliation(s)
- Jun Li
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892
| | - Huaibin Wang
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892
| | - Wei Yang
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892
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15
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Medina-Rivera M, Phelps S, Sridharan M, Becker J, Lamb N, Kumar C, Sutton M, Bielinsky A, Balakrishnan L, Surtees J. Elevated MSH2 MSH3 expression interferes with DNA metabolism in vivo. Nucleic Acids Res 2023; 51:12185-12206. [PMID: 37930834 PMCID: PMC10711559 DOI: 10.1093/nar/gkad934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/30/2023] [Accepted: 10/10/2023] [Indexed: 11/08/2023] Open
Abstract
The Msh2-Msh3 mismatch repair (MMR) complex in Saccharomyces cerevisiae recognizes and directs repair of insertion/deletion loops (IDLs) up to ∼17 nucleotides. Msh2-Msh3 also recognizes and binds distinct looped and branched DNA structures with varying affinities, thereby contributing to genome stability outside post-replicative MMR through homologous recombination, double-strand break repair (DSBR) and the DNA damage response. In contrast, Msh2-Msh3 promotes genome instability through trinucleotide repeat (TNR) expansions, presumably by binding structures that form from single-stranded (ss) TNR sequences. We previously demonstrated that Msh2-Msh3 binding to 5' ssDNA flap structures interfered with Rad27 (Fen1 in humans)-mediated Okazaki fragment maturation (OFM) in vitro. Here we demonstrate that elevated Msh2-Msh3 levels interfere with DNA replication and base excision repair in vivo. Elevated Msh2-Msh3 also induced a cell cycle arrest that was dependent on RAD9 and ELG1 and led to PCNA modification. These phenotypes also required Msh2-Msh3 ATPase activity and downstream MMR proteins, indicating an active mechanism that is not simply a result of Msh2-Msh3 DNA-binding activity. This study provides new mechanistic details regarding how excess Msh2-Msh3 can disrupt DNA replication and repair and highlights the role of Msh2-Msh3 protein abundance in Msh2-Msh3-mediated genomic instability.
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Affiliation(s)
- Melisa Medina-Rivera
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Samantha Phelps
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Madhumita Sridharan
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA
| | - Jordan Becker
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Natalie A Lamb
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Charanya Kumar
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Mark D Sutton
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Anja Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Lata Balakrishnan
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA
| | - Jennifer A Surtees
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
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16
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Thompson LM, Orr HT. HD and SCA1: Tales from two 30-year journeys since gene discovery. Neuron 2023; 111:3517-3530. [PMID: 37863037 PMCID: PMC10842341 DOI: 10.1016/j.neuron.2023.09.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/21/2023] [Accepted: 09/26/2023] [Indexed: 10/22/2023]
Abstract
One of the more transformative findings in human genetics was the discovery that the expansion of unstable nucleotide repeats underlies a group of inherited neurological diseases. A subset of these unstable repeat neurodegenerative diseases is due to the expansion of a CAG trinucleotide repeat encoding a stretch of glutamines, i.e., the polyglutamine (polyQ) repeat neurodegenerative diseases. Among the CAG/polyQ repeat diseases are Huntington's disease (HD) and spinocerebellar ataxia type 1 (SCA1), in which the expansions are within widely expressed proteins. Although both HD and SCA1 are autosomal dominantly inherited, and both typically cause mid- to late-life-onset movement disorders with cognitive decline, they each are characterized by distinct clinical characteristics and predominant sites of neuropathology. Importantly, the respective affected proteins, Huntingtin (HTT, HD) and Ataxin 1 (ATXN1, SCA1), have unique functions and biological properties. Here, we review HD and SCA1 with a focus on how their disease-specific and shared features may provide informative insights.
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Affiliation(s)
- Leslie M Thompson
- Department of Psychiatry and Human Behavior, Department of Neurobiology and Behavior, Department of Biological Chemistry, Institute of Memory Impairments and Neurological Disorders, Sue and Bill Gross Stem Cell Center, University of California Irvine, Irvine, CA 92697, USA
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota, Minneapolis and Saint Paul, MN 55455, USA.
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17
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Völker J, Breslauer KJ. How sequence alterations enhance the stability and delay expansion of DNA triplet repeat domains. QRB DISCOVERY 2023; 4:e8. [PMID: 37965436 PMCID: PMC10641665 DOI: 10.1017/qrd.2023.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 11/16/2023] Open
Abstract
DNA sequence alterations within DNA repeat domains inexplicably enhance the stability and delay the expansion of interrupted repeat domains. Here we propose mechanisms that rationalise such unanticipated outcomes. Specifically, we describe how interruption of a DNA repeat domain restricts the ensemble space available to dynamic, slip out, repeat bulge loops by introducing energetic barriers to loop migration. We explain how such barriers arise because some possible loop isomers result in energetically costly mismatches in the duplex portion of the repeat domain. We propose that the reduced ensemble space is the causative feature for the observed delay in repeat DNA expansion. We further posit that the observed loss of the interrupting repeat in some expanded DNAs reflects the transient occupation of loop isomer positions that result in a mismatch in the duplex stem due to 'leakiness' in the energy barrier. We propose that if the lifetime of such a low probability event allows for recognition by the mismatch repair system, then 'repair' of the repeat interruption can occur; thereby rationalising the absence of the interruption in the final expanded DNA 'product.' Our proposed mechanistic pathways provide reasoned explanations for what have been described as 'puzzling' observations, while also yielding insights into a biomedically important set of coupled genotypic phenomena that map the linkage between DNA origami thermodynamics and phenotypic disease states.
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Affiliation(s)
- Jens Völker
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
| | - Kenneth J. Breslauer
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, USA
- The Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
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18
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Nguyen TB, Miramontes R, Chillon-Marinas C, Maimon R, Vazquez-Sanchez S, Lau AL, McClure NR, England WE, Singha M, Stocksdale JT, Jang KH, Jung S, McKnight JI, Ho LN, Faull RLM, Steffan JS, Reidling JC, Jang C, Lee G, Cleveland DW, Lagier-Tourenne C, Spitale RC, Thompson LM. Aberrant splicing in Huntington's disease via disrupted TDP-43 activity accompanied by altered m6A RNA modification. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.31.565004. [PMID: 37961595 PMCID: PMC10635028 DOI: 10.1101/2023.10.31.565004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by a CAG repeat expansion in the first exon of the HTT gene encoding huntingtin. Prior reports have established a correlation between CAG expanded HTT and altered gene expression. However, the mechanisms leading to disruption of RNA processing in HD remain unclear. Here, our analysis of the reported HTT protein interactome identifies interactions with known RNA-binding proteins (RBPs). Total, long-read sequencing and targeted RASL-seq of RNAs from cortex and striatum of the HD mouse model R6/2 reveals increased exon skipping which is confirmed in Q150 and Q175 knock-in mice and in HD human brain. We identify the RBP TDP-43 and the N6-methyladenosine (m6A) writer protein methyltransferase 3 (METTL3) to be upstream regulators of exon skipping in HD. Along with this novel mechanistic insight, we observe decreased nuclear localization of TDP-43 and cytoplasmic accumulation of phosphorylated TDP-43 in HD mice and human brain. In addition, TDP-43 co-localizes with HTT in human HD brain forming novel nuclear aggregate-like bodies distinct from mutant HTT inclusions or previously observed TDP-43 pathologies. Binding of TDP-43 onto RNAs encoding HD-associated differentially expressed and aberrantly spliced genes is decreased. Finally, m6A RNA modification is reduced on RNAs abnormally expressed in striatum from HD R6/2 mouse brain, including at clustered sites adjacent to TDP-43 binding sites. Our evidence supports TDP-43 loss of function coupled with altered m6A modification as a novel mechanism underlying alternative splicing/unannotated exon usage in HD and highlights the critical nature of TDP-43 function across multiple neurodegenerative diseases.
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19
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Alhatim H, Abdullah MNH, Abu Bakar S, Amer SA. Effect of Carcinomas on Autosomal Trait Screening: A Review Article. Curr Issues Mol Biol 2023; 45:7275-7285. [PMID: 37754244 PMCID: PMC10529457 DOI: 10.3390/cimb45090460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/23/2023] [Accepted: 08/31/2023] [Indexed: 09/28/2023] Open
Abstract
This review highlights the effect of carcinomas on the results of the examination of autosomal genetic traits for identification and paternity tests when carcinoid tissue is the only source and no other samples are available. In DNA typing or genetic fingerprinting, variable elements are isolated and identified within the base pair sequences that form the DNA. The person's probable identity can be determined by analysing nucleotide sequences in particular regions of DNA unique to everyone. Genetics plays an increasingly important role in the risk stratification and management of carcinoma patients. The available information from previous studies has indicated that in some incidents, including mass disasters and crimes such as terrorist incidents, biological evidence may not be available at the scene of the accident, except for some unknown human remains found in the form of undefined human tissues. If these tissues have cancerous tumours, it may affect the examination of the genetic traits derived from these samples, thereby resulting in a failure to identify the person. Pathology units, more often, verify the identity of the patients who were diagnosed with cancer in reference to their deceased tumorous relatives. Genetic fingerprinting (GF) is also used in paternity testing when the alleged parent disappeared or died and earlier was diagnosed and treated for cancer.
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Affiliation(s)
- Husein Alhatim
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (H.A.); (S.A.B.)
| | - Muhammad Nazrul Hakim Abdullah
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (H.A.); (S.A.B.)
| | - Suhaili Abu Bakar
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (H.A.); (S.A.B.)
| | - Sayed Amin Amer
- Department of Forensic Sciences, College of Criminal Justice, Naif Arab University for Security Sciences, Riyadh 14812, Saudi Arabia
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20
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Suzuki MM, Iijima K, Ogami K, Shinjo K, Murofushi Y, Xie J, Wang X, Kitano Y, Mamiya A, Kibe Y, Nishimura T, Ohka F, Saito R, Sato S, Kobayashi J, Yao R, Miyata K, Kataoka K, Suzuki HI, Kondo Y. TUG1-mediated R-loop resolution at microsatellite loci as a prerequisite for cancer cell proliferation. Nat Commun 2023; 14:4521. [PMID: 37607907 PMCID: PMC10444773 DOI: 10.1038/s41467-023-40243-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/19/2023] [Indexed: 08/24/2023] Open
Abstract
Oncogene-induced DNA replication stress (RS) and consequent pathogenic R-loop formation are known to impede S phase progression. Nonetheless, cancer cells continuously proliferate under such high-stressed conditions through incompletely understood mechanisms. Here, we report taurine upregulated gene 1 (TUG1) long noncoding RNA (lncRNA), which is highly expressed in many types of cancers, as an important regulator of intrinsic R-loop in cancer cells. Under RS conditions, TUG1 is rapidly upregulated via activation of the ATR-CHK1 signaling pathway, interacts with RPA and DHX9, and engages in resolving R-loops at certain loci, particularly at the CA repeat microsatellite loci. Depletion of TUG1 leads to overabundant R-loops and enhanced RS, leading to substantial inhibition of tumor growth. Our data reveal a role of TUG1 as molecule important for resolving R-loop accumulation in cancer cells and suggest targeting TUG1 as a potent therapeutic approach for cancer treatment.
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Affiliation(s)
- Miho M Suzuki
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Kenta Iijima
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
- Laboratory Animal Facilities and Services, Preeminent Medical Photonics Education and Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Koichi Ogami
- Division of Molecular Oncology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Keiko Shinjo
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Yoshiteru Murofushi
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Jingqi Xie
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Xuebing Wang
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Yotaro Kitano
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Akira Mamiya
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Yuji Kibe
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Tatsunori Nishimura
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Fumiharu Ohka
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Ryuta Saito
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Shinya Sato
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, 2-3-2 Nakao, Asahi-ku, Yokohama, Kanagawa, 241-8515, Japan
| | - Junya Kobayashi
- School of Health Sciences at Narita, International University of Health and Welfare, 4-3 Kozunomori, Narita, Chiba, 286-8686, Japan
| | - Ryoji Yao
- Department of Cell Biology, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo, 135-8550, Japan
| | - Kanjiro Miyata
- Department of Materials Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Kazunori Kataoka
- Innovation Center of NanoMedicine, Kawasaki Institute of Industrial Promotion, 3-25-14 Tono-machi, Kawasaki-ku, Kanagawa, 210-0821, Japan
- Institute for Future Initiatives, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hiroshi I Suzuki
- Division of Molecular Oncology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
- Institute for Glyco-core Research (iGCORE), Tokai National Higher Education and Research System, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Yutaka Kondo
- Division of Cancer Biology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
- Institute for Glyco-core Research (iGCORE), Tokai National Higher Education and Research System, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.
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21
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Bai D, Zhu L, Jia Q, Duan X, Chen L, Wang X, Hou J, Jiang G, Yang S, Li S, Li XJ, Yin P. Loss of TDP-43 promotes somatic CAG repeat expansion in Huntington's disease knock-in mice. Prog Neurobiol 2023:102484. [PMID: 37315918 DOI: 10.1016/j.pneurobio.2023.102484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 04/26/2023] [Accepted: 06/09/2023] [Indexed: 06/16/2023]
Abstract
TAR binding protein 43 (TDP-43) is normally present in the nucleus but mislocalized in the cytoplasm in a number of neurodegenerative diseases including Huntington's disease (HD). The nuclear loss of TDP-43 impairs gene transcription and regulation. However, it remains to be investigated whether loss of TDP-43 influences trinucleotide CAG repeat expansion in the HD gene, a genetic cause for HD. Here we report that CRISPR/Cas9 mediated-knock down of endogenous TDP-43 in the striatum of HD knock-in mice promoted CAG repeat expansion, accompanied by the increased expression of the DNA mismatch repair genes, Msh3 and Mlh1, which have been reported to increase trinucleotide repeat instability. Furthermore, suppressing Msh3 and Mlh1 by CRISPR/Cas9 targeting diminished the CAG repeat expansion. These findings suggest that nuclear TDP-43 deficiency may dysregulate the expression of DNA mismatch repair genes, leading to CAG repeat expansion and contributing to the pathogenesis of CAG repeat diseases. DATA AVAILABILITY: The key data supporting the findings of this study are presented within the article and the Supplemental Information. The RNA sequencing reported in this paper can be found at https://doi.org/10.6084/m9.figshare.22639429.
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Affiliation(s)
- Dazhang Bai
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632; Department of Neurology, Affiliated Hospital of North Sichuan Medical College; Institute of neurological diseases, North Sichuan Medical College, Nanchong, China, 637000
| | - Longhong Zhu
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Qingqing Jia
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Xuezhi Duan
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Laiqiang Chen
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Xiang Wang
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Junqi Hou
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Guohui Jiang
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632; Department of Neurology, Affiliated Hospital of North Sichuan Medical College; Institute of neurological diseases, North Sichuan Medical College, Nanchong, China, 637000
| | - Su Yang
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Shihua Li
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632
| | - Xiao-Jiang Li
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632.
| | - Peng Yin
- Guangdong Key Laboratory of Non-human Primate Research, Guangdong-Hongkong-Macau Institute of CNS Regeneration, Jinan University, Guangzhou, 510632.
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22
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Xu P, Zhang J, Pan F, Mahn C, Roland C, Sagui C, Weninger K. Frustration Between Preferred States of Complementary Trinucleotide Repeat DNA Hairpins Anticorrelates with Expansion Disease Propensity. J Mol Biol 2023; 435:168086. [PMID: 37024008 PMCID: PMC10191799 DOI: 10.1016/j.jmb.2023.168086] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/21/2023] [Accepted: 03/30/2023] [Indexed: 04/08/2023]
Abstract
DNA trinucleotide repeat (TRs) expansion beyond a threshold often results in human neurodegenerative diseases. The mechanisms causing expansions remain unknown, although the tendency of TR ssDNA to self-associate into hairpins that slip along their length is widely presumed related. Here we apply single molecule FRET (smFRET) experiments and molecular dynamics simulations to determine conformational stabilities and slipping dynamics for CAG, CTG, GAC and GTC hairpins. Tetraloops are favored in CAG (89%), CTG (89%) and GTC (69%) while GAC favors triloops. We also determined that TTG interrupts near the loop in the CTG hairpin stabilize the hairpin against slipping. The different loop stabilities have implications for intermediate structures that may form when TR-containing duplex DNA opens. Opposing hairpins in the (CAG) ∙ (CTG) duplex would have matched stability whereas opposing hairpins in a (GAC) ∙ (GTC) duplex would have unmatched stability, introducing frustration in the (GAC) ∙ (GTC) opposing hairpins that could encourage their resolution to duplex DNA more rapidly than in (CAG) ∙ (CTG) structures. Given that the CAG and CTG TR can undergo large, disease-related expansion whereas the GAC and GTC sequences do not, these stability differences can inform and constrain models of expansion mechanisms of TR regions.
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Affiliation(s)
- Pengning Xu
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA. https://twitter.com/@XPengning
| | - Jiahui Zhang
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Feng Pan
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Chelsea Mahn
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Christopher Roland
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Celeste Sagui
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
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23
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Gao L, Xu W, Xin T, Song J. Application of third-generation sequencing to herbal genomics. FRONTIERS IN PLANT SCIENCE 2023; 14:1124536. [PMID: 36959935 PMCID: PMC10027759 DOI: 10.3389/fpls.2023.1124536] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
There is a long history of traditional medicine use. However, little genetic information is available for the plants used in traditional medicine, which limits the exploitation of these natural resources. Third-generation sequencing (TGS) techniques have made it possible to gather invaluable genetic information and develop herbal genomics. In this review, we introduce two main TGS techniques, PacBio SMRT technology and Oxford Nanopore technology, and compare the two techniques against Illumina, the predominant next-generation sequencing technique. In addition, we summarize the nuclear and organelle genome assemblies of commonly used medicinal plants, choose several examples from genomics, transcriptomics, and molecular identification studies to dissect the specific processes and summarize the advantages and disadvantages of the two TGS techniques when applied to medicinal organisms. Finally, we describe how we expect that TGS techniques will be widely utilized to assemble telomere-to-telomere (T2T) genomes and in epigenomics research involving medicinal plants.
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24
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Mengoli V, Ceppi I, Sanchez A, Cannavo E, Halder S, Scaglione S, Gaillard P, McHugh PJ, Riesen N, Pettazzoni P, Cejka P. WRN helicase and mismatch repair complexes independently and synergistically disrupt cruciform DNA structures. EMBO J 2023; 42:e111998. [PMID: 36541070 PMCID: PMC9890227 DOI: 10.15252/embj.2022111998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 11/07/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
The Werner Syndrome helicase, WRN, is a promising therapeutic target in cancers with microsatellite instability (MSI). Long-term MSI leads to the expansion of TA nucleotide repeats proposed to form cruciform DNA structures, which in turn cause DNA breaks and cell lethality upon WRN downregulation. Here we employed biochemical assays to show that WRN helicase can efficiently and directly unfold cruciform structures, thereby preventing their cleavage by the SLX1-SLX4 structure-specific endonuclease. TA repeats are particularly prone to form cruciform structures, explaining why these DNA sequences are preferentially broken in MSI cells upon WRN downregulation. We further demonstrate that the activity of the DNA mismatch repair (MMR) complexes MutSα (MSH2-MSH6), MutSβ (MSH2-MSH3), and MutLα (MLH1-PMS2) similarly decreases the level of DNA cruciforms, although the mechanism is different from that employed by WRN. When combined, WRN and MutLα exhibited higher than additive effects in in vitro cruciform processing, suggesting that WRN and the MMR proteins may cooperate. Our data explain how WRN and MMR defects cause genome instability in MSI cells with expanded TA repeats, and provide a mechanistic basis for their recently discovered synthetic-lethal interaction with promising applications in precision cancer therapy.
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Affiliation(s)
- Valentina Mengoli
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Ilaria Ceppi
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Aurore Sanchez
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Elda Cannavo
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Swagata Halder
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
| | - Sarah Scaglione
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix‐Marseille Université, Institut Paoli‐CalmettesMarseilleFrance
| | - Pierre‐Henri Gaillard
- Centre de Recherche en Cancérologie de Marseille, CRCM, Inserm, CNRS, Aix‐Marseille Université, Institut Paoli‐CalmettesMarseilleFrance
| | - Peter J McHugh
- Department of Oncology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe HospitalUniversity of OxfordOxfordUK
| | - Nathalie Riesen
- Roche Pharma Research & Early Development pREDRoche Innovation CenterBaselSwitzerland
| | | | - Petr Cejka
- Faculty of Biomedical Sciences, Institute for Research in BiomedicineUniversità della Svizzera italiana (USI)BellinzonaSwitzerland
- Department of Biology, Institute of BiochemistryEidgenössische Technische Hochschule (ETH)ZürichSwitzerland
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25
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Fan C, Chen K, Wang Y, Ball EV, Stenson PD, Mort M, Bacolla A, Kehrer-Sawatzki H, Tainer JA, Cooper DN, Zhao H. Profiling human pathogenic repeat expansion regions by synergistic and multi-level impacts on molecular connections. Hum Genet 2023; 142:245-274. [PMID: 36344696 PMCID: PMC10290229 DOI: 10.1007/s00439-022-02500-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/24/2022] [Indexed: 11/09/2022]
Abstract
Whilst DNA repeat expansions cause numerous heritable human disorders, their origins and underlying pathological mechanisms are often unclear. We collated a dataset comprising 224 human repeat expansions encompassing 203 different genes, and performed a systematic analysis with respect to key topological features at the DNA, RNA and protein levels. Comparison with controls without known pathogenicity and genomic regions lacking repeats, allowed the construction of the first tool to discriminate repeat regions harboring pathogenic repeat expansions (DPREx). At the DNA level, pathogenic repeat expansions exhibited stronger signals for DNA regulatory factors (e.g. H3K4me3, transcription factor-binding sites) in exons, promoters, 5'UTRs and 5'genes but were not significantly different from controls in introns, 3'UTRs and 3'genes. Additionally, pathogenic repeat expansions were also found to be enriched in non-B DNA structures. At the RNA level, pathogenic repeat expansions were characterized by lower free energy for forming RNA secondary structure and were closer to splice sites in introns, exons, promoters and 5'genes than controls. At the protein level, pathogenic repeat expansions exhibited a preference to form coil rather than other types of secondary structure, and tended to encode surface-located protein domains. Guided by these features, DPREx ( http://biomed.nscc-gz.cn/zhaolab/geneprediction/# ) achieved an Area Under the Curve (AUC) value of 0.88 in a test on an independent dataset. Pathogenic repeat expansions are thus located such that they exert a synergistic influence on the gene expression pathway involving inter-molecular connections at the DNA, RNA and protein levels.
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Affiliation(s)
- Cong Fan
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang West Road, Guangzhou, 500001, People's Republic of China
| | - Ken Chen
- School of Computer Science and Engineering, Sun Yat-Sen University, Guangzhou, 500001, China
| | - Yukai Wang
- School of Life Science, Sun Yat-Sen University, Guangzhou, 500001, China
| | - Edward V Ball
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Peter D Stenson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Matthew Mort
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | | | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Avenue, Houston, TX, 77030, USA
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff, CF14 4XN, UK
| | - Huiying Zhao
- Department of Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang West Road, Guangzhou, 500001, People's Republic of China.
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26
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Hamim I, Sekine KT, Komatsu K. How do emerging long-read sequencing technologies function in transforming the plant pathology research landscape? PLANT MOLECULAR BIOLOGY 2022; 110:469-484. [PMID: 35962900 DOI: 10.1007/s11103-022-01305-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Long-read sequencing technologies are revolutionizing the sequencing and analysis of plant and pathogen genomes and transcriptomes, as well as contributing to emerging areas of interest in plant-pathogen interactions, disease management techniques, and the introduction of new plant varieties or cultivars. Long-read sequencing (LRS) technologies are progressively being implemented to study plants and pathogens of agricultural importance, which have substantial economic effects. The variability and complexity of the genome and transcriptome affect plant growth, development and pathogen responses. Overcoming the limitations of second-generation sequencing, LRS technology has significantly increased the length of a single contiguous read from a few hundred to millions of base pairs. Because of the longer read lengths, new analysis methods and tools have been developed for plant and pathogen genomics and transcriptomics. LRS technologies enable faster, more efficient, and high-throughput ultralong reads, allowing direct sequencing of genomes that would be impossible or difficult to investigate using short-read sequencing approaches. These benefits include genome assembly in repetitive areas, creating more comprehensive and exact genome determinations, assembling full-length transcripts, and detecting DNA and RNA alterations. Furthermore, these technologies allow for the identification of transcriptome diversity, significant structural variation analysis, and direct epigenetic mark detection in plant and pathogen genomic regions. LRS in plant pathology is found efficient for identifying and characterization of effectors in plants as well as known and unknown plant pathogens. In this review, we investigate how these technologies are transforming the landscape of determination and characterization of plant and pathogen genomes and transcriptomes efficiently and accurately. Moreover, we highlight potential areas of interest offered by LRS technologies for future study into plant-pathogen interactions, disease control strategies, and the development of new plant varieties or cultivars.
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Affiliation(s)
- Islam Hamim
- Laboratory of Plant Pathology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
- International Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
- Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Ken-Taro Sekine
- Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan
| | - Ken Komatsu
- Laboratory of Plant Pathology, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan.
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27
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Ulhusna A, Murata A, Nakatani K. Inhibitory Effects of Mismatch Binding Molecules on the Repair Reaction of Uracil-Containing DNA. Biochemistry 2022; 61:2522-2530. [PMID: 36250600 DOI: 10.1021/acs.biochem.2c00344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The stable R-loop formed during transcription induces enzyme-mediated deamination of cytosine, and the uracil in the DNA produced activates the base excision repair (BER) pathway. DNA cleavage involved in the BER pathway is thought to be one of the possible causes of trinucleotide repeat instability. Here, we performed an in vitro assay to investigate the effect of a DNA-binding small molecule, naphthyridine carbamate dimer (NCD), on BER enzyme reactions. The gel electrophoretic mobility shift assay (EMSA) and thermal melting analysis revealed the binding of NCD to a 5'-XGG-3'/5'-XGG-3' triad (X = C or U or apurinic/apyrimidinic site), which is a mimic of a BER enzyme substrate. Polyacrylamide gel electrophoresis (PAGE) of the reaction products of these substrates with hSMUG1 and APE1 enzymes in the presence of NCD showed that NCD interfered with the repair reaction in the 5'-XGG-3'/5'-XGG-3' triad. These findings would broaden the potential of small molecules in modulating trinucleotide repeat instability.
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Affiliation(s)
- Anisa Ulhusna
- Department of Regulatory Bioorganic Chemistry, SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Asako Murata
- Department of Regulatory Bioorganic Chemistry, SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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28
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Timchenko L. Myotonic Dystrophy: From Molecular Pathogenesis to Therapeutics. Int J Mol Sci 2022; 23:ijms231911954. [PMID: 36233257 PMCID: PMC9570427 DOI: 10.3390/ijms231911954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 09/06/2022] [Indexed: 11/16/2022] Open
Affiliation(s)
- Lubov Timchenko
- Departments of Neurology and Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, OH 45229, USA
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29
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Masnovo C, Lobo AF, Mirkin SM. Replication dependent and independent mechanisms of GAA repeat instability. DNA Repair (Amst) 2022; 118:103385. [PMID: 35952488 PMCID: PMC9675320 DOI: 10.1016/j.dnarep.2022.103385] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 11/20/2022]
Abstract
Trinucleotide repeat instability is a driver of human disease. Large expansions of (GAA)n repeats in the first intron of the FXN gene are the cause Friedreich's ataxia (FRDA), a progressive degenerative disorder which cannot yet be prevented or treated. (GAA)n repeat instability arises during both replication-dependent processes, such as cell division and intergenerational transmission, as well as in terminally differentiated somatic tissues. Here, we provide a brief historical overview on the discovery of (GAA)n repeat expansions and their association to FRDA, followed by recent advances in the identification of triplex H-DNA formation and replication fork stalling. The main body of this review focuses on the last decade of progress in understanding the mechanism of (GAA)n repeat instability during DNA replication and/or DNA repair. We propose that the discovery of additional mechanisms of (GAA)n repeat instability can be achieved via both comparative approaches to other repeat expansion diseases and genome-wide association studies. Finally, we discuss the advances towards FRDA prevention or amelioration that specifically target (GAA)n repeat expansions.
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Affiliation(s)
- Chiara Masnovo
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Ayesha F Lobo
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA.
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30
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Heterogeneous migration routes of DNA triplet repeat slip-outs. BIOPHYSICAL REPORTS 2022; 2:None. [PMID: 36299495 PMCID: PMC9586884 DOI: 10.1016/j.bpr.2022.100070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 08/08/2022] [Indexed: 12/02/2022]
Abstract
It is unclear how the length of a repetitive DNA tract determines the onset and progression of repeat expansion diseases, but the dynamics of secondary DNA structures formed by repeat sequences are believed to play an important role. It was recently shown that three-way DNA junctions containing slip-out hairpins of CAG or CTG repeats and contiguous triplet repeats in the adjacent duplex displayed single-molecule FRET (smFRET) dynamics that were ascribed to both local conformational motions and longer-range branch migration. Here we explore these so-called "mobile" slip-out structures through a detailed kinetic analysis of smFRET trajectories and coarse-grained modeling. Despite the apparent structural simplicity, with six FRET states resolvable, most smFRET states displayed biexponential dwell-time distributions, attributed to structural heterogeneity and overlapping FRET states. Coarse-grained modeling for a (GAC)10 repeat slip-out included trajectories that corresponded to a complete round of branch migration; the structured free energy landscape between slippage events supports the dynamical complexity observed by smFRET. A hairpin slip-out with 40 CAG repeats, which is above the repeat length required for disease in several triplet repeat disorders, displayed smFRET dwell times that were on average double those of 3WJs with 10 repeats. The rate of secondary-structure rearrangement via branch migration, relative to particular DNA processing pathways, may be an important factor in the expansion of triplet repeat expansion diseases.
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31
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Yousuf A, Ahmed N, Qurashi A. Non-canonical DNA/RNA structures associated with the pathogenesis of Fragile X-associated tremor/ataxia syndrome and Fragile X syndrome. Front Genet 2022; 13:866021. [PMID: 36110216 PMCID: PMC9468596 DOI: 10.3389/fgene.2022.866021] [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: 01/30/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) and fragile X syndrome (FXS) are primary examples of fragile X-related disorders (FXDs) caused by abnormal expansion of CGG repeats above a certain threshold in the 5'-untranslated region of the fragile X mental retardation (FMR1) gene. Both diseases have distinct clinical manifestations and molecular pathogenesis. FXTAS is a late-adult-onset neurodegenerative disorder caused by a premutation (PM) allele (CGG expansion of 55-200 repeats), resulting in FMR1 gene hyperexpression. On the other hand, FXS is a neurodevelopmental disorder that results from a full mutation (FM) allele (CGG expansions of ≥200 repeats) leading to heterochromatization and transcriptional silencing of the FMR1 gene. The main challenge is to determine how CGG repeat expansion affects the fundamentally distinct nature of FMR1 expression in FM and PM ranges. Abnormal CGG repeat expansions form a variety of non-canonical DNA and RNA structures that can disrupt various cellular processes and cause distinct effects in PM and FM alleles. Here, we review these structures and how they are related to underlying mutations and disease pathology in FXS and FXTAS. Finally, as new CGG expansions within the genome have been identified, it will be interesting to determine their implications in disease pathology and treatment.
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Affiliation(s)
| | | | - Abrar Qurashi
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
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32
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Guo P, Han D. Targeting Pathogenic DNA and RNA Repeats: A Conceptual Therapeutic Way for Repeat Expansion Diseases. Chemistry 2022; 28:e202201749. [PMID: 35727679 DOI: 10.1002/chem.202201749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Indexed: 11/06/2022]
Abstract
Expansions of short tandem repeats (STRs) in the human genome cause nearly 50 neurodegenerative diseases, which are mostly inheritable, nonpreventable and incurable, posing as a huge threat to human health. Non-B DNAs formed by STRs are thought to be structural intermediates that can cause repeat expansions. The subsequent transcripts harboring expanded RNA repeats can further induce cellular toxicity through forming specific structures. Direct targeting of these pathogenic DNA and RNA repeats has emerged as a new potential therapeutic strategy to cure repeat expansion diseases. In this conceptual review, we first introduce the roles of DNA and RNA structures in the genetic instabilities and pathomechanisms of repeat expansion diseases, then describe structural features of DNA and RNA repeats with a focus on the tertiary structures determined by X-ray crystallography and solution nuclear magnetic resonance spectroscopy, and finally discuss recent progress and perspectives of developing chemical tools that target pathogenic DNA and RNA repeats for curing repeat expansion diseases.
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Affiliation(s)
- Pei Guo
- The Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital), Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, P. R. China
| | - Da Han
- The Cancer Hospital of the University of Chinese Academy of Sciences, Zhejiang Cancer Hospital), Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences, Hangzhou, Zhejiang, 310022, P. R. China.,Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, State Key Laboratory of Oncogenes and Related Genes, Renji Hospital, School of Medicine Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
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33
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Williams FN, Scaglione KM. Insights on Microsatellite Characteristics, Evolution, and Function From the Social Amoeba Dictyostelium discoideum. Front Neurosci 2022; 16:886837. [PMID: 35769695 PMCID: PMC9234386 DOI: 10.3389/fnins.2022.886837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Microsatellites are repetitive sequences commonly found in the genomes of higher organisms. These repetitive sequences are prone to expansion or contraction, and when microsatellite expansion occurs in the regulatory or coding regions of genes this can result in a number of diseases including many neurodegenerative diseases. Unlike in humans and other organisms, the social amoeba Dictyostelium discoideum contains an unusually high number of microsatellites. Intriguingly, many of these microsatellites fall within the coding region of genes, resulting in nearly 10,000 homopolymeric repeat proteins within the Dictyostelium proteome. Surprisingly, among the most common of these repeats are polyglutamine repeats, a type of repeat that causes a class of nine neurodegenerative diseases in humans. In this minireview, we summarize what is currently known about homopolymeric repeats and microsatellites in Dictyostelium discoideum and discuss the potential utility of Dictyostelium for identifying novel mechanisms that utilize and regulate regions of repetitive DNA.
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Affiliation(s)
- Felicia N. Williams
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, United States
| | - K. Matthew Scaglione
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, United States
- Department of Neurology, Duke University, Durham, NC, United States
- Duke Center for Neurodegeneration and Neurotherapeutics, Duke University, Durham, NC, United States
- *Correspondence: K. Matthew Scaglione,
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Lee J, Li K, Zimmerman SC. A Selective Alkylating Agent for CTG Repeats in Myotonic Dystrophy Type 1. ACS Chem Biol 2022; 17:1103-1110. [PMID: 35483041 DOI: 10.1021/acschembio.1c00949] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Disease intervention at the DNA level generally has been avoided because of off-target effects. Recent advances in genome editing technologies using CRISPR-Cas9 have opened a new era in DNA-targeted therapeutic approaches. However, delivery of such systems remains a major challenge. Here, we report a selective DNA-modifying small molecule that targets a disease-specific structure and mismatches involved in myotonic dystrophy type 1 (DM1). This ligand alkylates T-T mismatch-containing hairpins formed in the expanded CTG repeats (d(CTG)exp) in DM1. Ligand alkylation of d(CTG)exp inhibits the transcription of d(CAG·CTG)exp, thereby reducing the level of the toxic r(CUG)exp transcript. The bioactivity of the ligand also included a reduction in DM1 pathological features such as disease foci formation and misregulation of pre-mRNA splicing in DM1 model cells. Furthermore, the CTG-alkylating ligand may change the d(CAG·CTG)exp repeat length dynamics in DM1 patient cells. Our strategy of linking an alkylating moiety to a DNA mismatch-selective small molecule may be generally applicable to other repeat expansion diseases such as Huntington's disease and amyotrophic lateral sclerosis.
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Affiliation(s)
- JuYeon Lee
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ke Li
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Steven C. Zimmerman
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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Fakharzadeh A, Zhang J, Roland C, Sagui C. Novel eGZ-motif formed by regularly extruded guanine bases in a left-handed Z-DNA helix as a major motif behind CGG trinucleotide repeats. Nucleic Acids Res 2022; 50:4860-4876. [PMID: 35536254 PMCID: PMC9122592 DOI: 10.1093/nar/gkac339] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/19/2022] [Accepted: 05/05/2022] [Indexed: 12/19/2022] Open
Abstract
The expansion of d(CGG) trinucleotide repeats (TRs) lies behind several important neurodegenerative diseases. Atypical DNA secondary structures have been shown to trigger TR expansion: their characterization is important for a molecular understanding of TR disease. CD spectroscopy experiments in the last decade have unequivocally demonstrated that CGG runs adopt a left-handed Z-DNA conformation, whose features remain uncertain because it entails accommodating GG mismatches. In order to find this missing motif, we have carried out molecular dynamics (MD) simulations to explore all the possible Z-DNA helices that potentially form after the transition from B- to Z-DNA. Such helices combine either CpG or GpC Watson-Crick steps in Z-DNA form with GG-mismatch conformations set as either intrahelical or extrahelical; and participating in BZ or ZZ junctions or in alternately extruded conformations. Characterization of the stability and structural features (especially overall left-handedness, higher-temperature and steered MD simulations) identified two novel Z-DNA helices: the most stable one displays alternately extruded Gs, and is followed by a helix with symmetrically extruded ZZ junctions. The G-extrusion favors a seamless stacking of the Watson-Crick base pairs; extruded Gs favor syn conformations and display hydrogen-bonding and stacking interactions. Such conformations could have the potential to hijack the MMR complex, thus triggering further expansion.
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Affiliation(s)
- Ashkan Fakharzadeh
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Jiahui Zhang
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Christopher Roland
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Celeste Sagui
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
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36
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Barbé L, Finkbeiner S. Genetic and Epigenetic Interplay Define Disease Onset and Severity in Repeat Diseases. Front Aging Neurosci 2022; 14:750629. [PMID: 35592702 PMCID: PMC9110800 DOI: 10.3389/fnagi.2022.750629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
Repeat diseases, such as fragile X syndrome, myotonic dystrophy, Friedreich ataxia, Huntington disease, spinocerebellar ataxias, and some forms of amyotrophic lateral sclerosis, are caused by repetitive DNA sequences that are expanded in affected individuals. The age at which an individual begins to experience symptoms, and the severity of disease, are partially determined by the size of the repeat. However, the epigenetic state of the area in and around the repeat also plays an important role in determining the age of disease onset and the rate of disease progression. Many repeat diseases share a common epigenetic pattern of increased methylation at CpG islands near the repeat region. CpG islands are CG-rich sequences that are tightly regulated by methylation and are often found at gene enhancer or insulator elements in the genome. Methylation of CpG islands can inhibit binding of the transcriptional regulator CTCF, resulting in a closed chromatin state and gene down regulation. The downregulation of these genes leads to some disease-specific symptoms. Additionally, a genetic and epigenetic interplay is suggested by an effect of methylation on repeat instability, a hallmark of large repeat expansions that leads to increasing disease severity in successive generations. In this review, we will discuss the common epigenetic patterns shared across repeat diseases, how the genetics and epigenetics interact, and how this could be involved in disease manifestation. We also discuss the currently available stem cell and mouse models, which frequently do not recapitulate epigenetic patterns observed in human disease, and propose alternative strategies to study the role of epigenetics in repeat diseases.
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Affiliation(s)
- Lise Barbé
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
| | - Steve Finkbeiner
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, CA, United States
- Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
- *Correspondence: Steve Finkbeiner,
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Deshmukh AL, Caron MC, Mohiuddin M, Lanni S, Panigrahi GB, Khan M, Engchuan W, Shum N, Faruqui A, Wang P, Yuen RKC, Nakamori M, Nakatani K, Masson JY, Pearson CE. FAN1 exo- not endo-nuclease pausing on disease-associated slipped-DNA repeats: A mechanism of repeat instability. Cell Rep 2021; 37:110078. [PMID: 34879276 DOI: 10.1016/j.celrep.2021.110078] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/02/2021] [Accepted: 11/09/2021] [Indexed: 12/19/2022] Open
Abstract
Ongoing inchworm-like CAG and CGG repeat expansions in brains, arising by aberrant processing of slipped DNAs, may drive Huntington's disease, fragile X syndrome, and autism. FAN1 nuclease modifies hyper-expansion rates by unknown means. We show that FAN1, through iterative cycles, binds, dimerizes, and cleaves slipped DNAs, yielding striking exo-nuclease pauses along slip-outs: 5'-C↓A↓GC↓A↓G-3' and 5'-C↓T↓G↓C↓T↓G-3'. CAG excision is slower than CTG and requires intra-strand A·A and T·T mismatches. Fully paired hairpins arrested excision, whereas disease-delaying CAA interruptions further slowed excision. Endo-nucleolytic cleavage is insensitive to slip-outs. Rare FAN1 variants are found in individuals with autism with CGG/CCG expansions, and CGG/CCG slip-outs show exo-nuclease pauses. The slip-out-specific ligand, naphthyridine-azaquinolone, which induces contractions of expanded repeats in vivo, requires FAN1 for its effect, and protects slip-outs from FAN1 exo-, but not endo-, nucleolytic digestion. FAN1's inchworm pausing of slip-out excision rates is well suited to modify inchworm expansion rates, which modify disease onset and progression.
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Affiliation(s)
- Amit Laxmikant Deshmukh
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Marie-Christine Caron
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Québec City, QC G1R 3S3, Canada; Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec City, QC G1R 3S3, Canada
| | - Mohiuddin Mohiuddin
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Stella Lanni
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Gagan B Panigrahi
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Mahreen Khan
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Worrawat Engchuan
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Natalie Shum
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aisha Faruqui
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Peixiang Wang
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Ryan K C Yuen
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, the Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047, Japan
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Québec City, QC G1R 3S3, Canada; Department of Molecular Biology, Medical Biochemistry, and Pathology, Laval University Cancer Research Center, Québec City, QC G1R 3S3, Canada
| | - Christopher E Pearson
- Program of Genetics & Genome Biology, The Hospital for Sick Children, PGCRL, Toronto, Canada, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Program of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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38
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Chen Z, He X. Application of third-generation sequencing in cancer research. MEDICAL REVIEW (BERLIN, GERMANY) 2021; 1:150-171. [PMID: 37724303 PMCID: PMC10388785 DOI: 10.1515/mr-2021-0013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/09/2021] [Indexed: 09/20/2023]
Abstract
In the past several years, nanopore sequencing technology from Oxford Nanopore Technologies (ONT) and single-molecule real-time (SMRT) sequencing technology from Pacific BioSciences (PacBio) have become available to researchers and are currently being tested for cancer research. These methods offer many advantages over most widely used high-throughput short-read sequencing approaches and allow the comprehensive analysis of transcriptomes by identifying full-length splice isoforms and several other posttranscriptional events. In addition, these platforms enable structural variation characterization at a previously unparalleled resolution and direct detection of epigenetic marks in native DNA and RNA. Here, we present a comprehensive summary of important applications of these technologies in cancer research, including the identification of complex structure variants, alternatively spliced isoforms, fusion transcript events, and exogenous RNA. Furthermore, we discuss the impact of the newly developed nanopore direct RNA sequencing (RNA-Seq) approach in advancing epitranscriptome research in cancer. Although the unique challenges still present for these new single-molecule long-read methods, they will unravel many aspects of cancer genome complexity in unprecedented ways and present an encouraging outlook for continued application in an increasing number of different cancer research settings.
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Affiliation(s)
- Zhiao Chen
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xianghuo He
- Fudan University Shanghai Cancer Center and Institutes of Biomedical Sciences, Fudan University, Shanghai, China
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
- Key Laboratory of Breast Cancer in Shanghai, Fudan University Shanghai Cancer Center, Fudan University, Shanghai, China
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Abstract
At fifteen different genomic locations, the expansion of a CAG/CTG repeat causes a neurodegenerative or neuromuscular disease, the most common being Huntington's disease and myotonic dystrophy type 1. These disorders are characterized by germline and somatic instability of the causative CAG/CTG repeat mutations. Repeat lengthening, or expansion, in the germline leads to an earlier age of onset or more severe symptoms in the next generation. In somatic cells, repeat expansion is thought to precipitate the rate of disease. The mechanisms underlying repeat instability are not well understood. Here we review the mammalian model systems that have been used to study CAG/CTG repeat instability, and the modifiers identified in these systems. Mouse models have demonstrated prominent roles for proteins in the mismatch repair pathway as critical drivers of CAG/CTG instability, which is also suggested by recent genome-wide association studies in humans. We draw attention to a network of connections between modifiers identified across several systems that might indicate pathway crosstalk in the context of repeat instability, and which could provide hypotheses for further validation or discovery. Overall, the data indicate that repeat dynamics might be modulated by altering the levels of DNA metabolic proteins, their regulation, their interaction with chromatin, or by direct perturbation of the repeat tract. Applying novel methodologies and technologies to this exciting area of research will be needed to gain deeper mechanistic insight that can be harnessed for therapies aimed at preventing repeat expansion or promoting repeat contraction.
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Affiliation(s)
- Vanessa C. Wheeler
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA,Department of Neurology, Harvard Medical School, Boston, MA, USA,Correspondence to: Vanessa C. Wheeler, Center for Genomic Medicine, Massachusetts Hospital, Boston MAA 02115, USA. E-mail: . and Vincent Dion, UK Dementia Research Institute at Cardiff University, Hadyn Ellis Building, Maindy Road, CF24 4HQ Cardiff, UK. E-mail:
| | - Vincent Dion
- UK Dementia Research Institute at Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, UK,Correspondence to: Vanessa C. Wheeler, Center for Genomic Medicine, Massachusetts Hospital, Boston MAA 02115, USA. E-mail: . and Vincent Dion, UK Dementia Research Institute at Cardiff University, Hadyn Ellis Building, Maindy Road, CF24 4HQ Cardiff, UK. E-mail:
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40
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Xue S, Zhang Y, Liu F, Huang W, Xu R, Wang J. Olaparib combined with chemotherapy for treatment of T-cell acute lymphoblastic leukemia relapse after unrelated umbilical cord blood transplantation. Leuk Lymphoma 2021; 63:478-482. [PMID: 34608827 DOI: 10.1080/10428194.2021.1984453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Song Xue
- Department of Hematology, Aerospace Center Hospital, Peking University Aerospace School of Clinical Medicine, Beijing, China
| | - Yongping Zhang
- Department of Hematology, Aerospace Center Hospital, Peking University Aerospace School of Clinical Medicine, Beijing, China
| | - Fuhong Liu
- Department of Hematology, Aerospace Center Hospital, Peking University Aerospace School of Clinical Medicine, Beijing, China
| | - Wenqiu Huang
- Department of Hematology, Aerospace Center Hospital, Peking University Aerospace School of Clinical Medicine, Beijing, China
| | - Ri Xu
- Beijing Bo Fu Rui Gene Diagnostics Co., Ltd, Beijing, China
| | - Jingbo Wang
- Department of Hematology, Aerospace Center Hospital, Peking University Aerospace School of Clinical Medicine, Beijing, China
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41
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Gold MA, Whalen JM, Freon K, Hong Z, Iraqui I, Lambert SAE, Freudenreich CH. Restarted replication forks are error-prone and cause CAG repeat expansions and contractions. PLoS Genet 2021; 17:e1009863. [PMID: 34673780 PMCID: PMC8562783 DOI: 10.1371/journal.pgen.1009863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 11/02/2021] [Accepted: 10/06/2021] [Indexed: 12/16/2022] Open
Abstract
Disease-associated trinucleotide repeats form secondary DNA structures that interfere with replication and repair. Replication has been implicated as a mechanism that can cause repeat expansions and contractions. However, because structure-forming repeats are also replication barriers, it has been unclear whether the instability occurs due to slippage during normal replication progression through the repeat, slippage or misalignment at a replication stall caused by the repeat, or during subsequent replication of the repeat by a restarted fork that has altered properties. In this study, we have specifically addressed the fidelity of a restarted fork as it replicates through a CAG/CTG repeat tract and its effect on repeat instability. To do this, we used a well-characterized site-specific replication fork barrier (RFB) system in fission yeast that creates an inducible and highly efficient stall that is known to restart by recombination-dependent replication (RDR), in combination with long CAG repeat tracts inserted at various distances and orientations with respect to the RFB. We find that replication by the restarted fork exhibits low fidelity through repeat sequences placed 2-7 kb from the RFB, exhibiting elevated levels of Rad52- and Rad8ScRad5/HsHLTF-dependent instability. CAG expansions and contractions are not elevated to the same degree when the tract is just in front or behind the barrier, suggesting that the long-traveling Polδ-Polδ restarted fork, rather than fork reversal or initial D-loop synthesis through the repeat during stalling and restart, is the greatest source of repeat instability. The switch in replication direction that occurs due to replication from a converging fork while the stalled fork is held at the barrier is also a significant contributor to the repeat instability profile. Our results shed light on a long-standing question of how fork stalling and RDR contribute to expansions and contractions of structure-forming trinucleotide repeats, and reveal that tolerance to replication stress by fork restart comes at the cost of increased instability of repetitive sequences.
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Affiliation(s)
- Michaela A. Gold
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
| | - Jenna M. Whalen
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
| | - Karine Freon
- Institut Curie, Université PSL, Orsay, France
- Université Paris-Saclay, Orsay, France
| | - Zixin Hong
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
| | - Ismail Iraqui
- Institut Curie, Université PSL, Orsay, France
- Université Paris-Saclay, Orsay, France
| | - Sarah A. E. Lambert
- Institut Curie, Université PSL, Orsay, France
- Université Paris-Saclay, Orsay, France
- Equipes Labélisées Ligue Nationale Contre Le Cancer, Orsay, France
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Chan KY, Li X, Ortega J, Gu L, Li GM. DNA polymerase θ promotes CAG•CTG repeat expansions in Huntington's disease via insertion sequences of its catalytic domain. J Biol Chem 2021; 297:101144. [PMID: 34473992 PMCID: PMC8463855 DOI: 10.1016/j.jbc.2021.101144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/23/2021] [Accepted: 08/27/2021] [Indexed: 12/04/2022] Open
Abstract
Huntington's disease (HD), a neurodegenerative disease characterized by progressive dementia, psychiatric problems, and chorea, is known to be caused by CAG repeat expansions in the HD gene HTT. However, the mechanism of this pathology is not fully understood. The translesion DNA polymerase θ (Polθ) carries a large insertion sequence in its catalytic domain, which has been shown to allow DNA loop-outs in the primer strand. As a result of high levels of oxidative DNA damage in neural cells and Polθ's subsequent involvement in base excision repair of oxidative DNA damage, we hypothesized that Polθ contributes to CAG repeat expansion while repairing oxidative damage within HTT. Here, we performed Polθ-catalyzed in vitro DNA synthesis using various CAG•CTG repeat DNA substrates that are similar to base excision repair intermediates. We show that Polθ efficiently extends (CAG)n•(CTG)n hairpin primers, resulting in hairpin retention and repeat expansion. Polθ also triggers repeat expansions to pass the threshold for HD when the DNA template contains 35 repeats upward. Strikingly, Polθ depleted of the catalytic insertion fails to induce repeat expansions regardless of primers and templates used, indicating that the insertion sequence is responsible for Polθ's error-causing activity. In addition, the level of chromatin-bound Polθ in HD cells is significantly higher than in non-HD cells and exactly correlates with the degree of CAG repeat expansion, implying Polθ's involvement in triplet repeat instability. Therefore, we have identified Polθ as a potent factor that promotes CAG•CTG repeat expansions in HD and other neurodegenerative disorders.
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Affiliation(s)
- Kara Y Chan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA; Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Xueying Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Janice Ortega
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Liya Gu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA; Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
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Yoshioka H, Li A, Suzuki A, Ramakrishnan SS, Zhao Z, Iwata J. Identification of microRNAs and gene regulatory networks in cleft lip common in humans and mice. Hum Mol Genet 2021; 30:1881-1893. [PMID: 34104955 PMCID: PMC8444451 DOI: 10.1093/hmg/ddab151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/17/2021] [Accepted: 05/31/2021] [Indexed: 12/11/2022] Open
Abstract
The etiology of cleft lip with/without cleft palate (CL/P), one of the most frequent craniofacial birth defects worldwide, is complicated by contributions of both genetic and environmental factors. Understanding the etiology of these conditions is essential for developing preventive strategies. This study thus aims to identify regulatory networks of microRNAs (miRNAs), transcriptional factors (TFs) and non-TF genes associated with cleft lip (CL) that are conserved in humans and mice. Notably, we found that miR-27b, miR-133b, miR-205, miR-376b and miR-376c were involved in the regulation of CL-associated gene expression in both humans and mice. Among the candidate miRNAs, the overexpression of miR-27b, miR-133b and miR-205, but not miR-376b and miR-376c, significantly inhibited cell proliferation through suppression of CL-associated genes (miR-27b suppressed PAX9 and RARA; miR-133b suppressed FGFR1, PAX7, and SUMO1; and miR-205 suppressed PAX9 and RARA) in cultured human and mouse lip mesenchymal cells. Taken together, our results suggest that elevated expression of miR-27b, miR-133b and miR-205 may play a crucial role in CL through the suppression of genes associated with CL.
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Affiliation(s)
- Hiroki Yoshioka
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Aimin Li
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Akiko Suzuki
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Sai Shankar Ramakrishnan
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
| | - Zhongming Zhao
- Center for Precision Health, School of Biomedical Informatics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Human Genetics Center, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
| | - Junichi Iwata
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston, Houston, TX 77054, USA
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA
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44
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McGurk L, Rifai OM, Shcherbakova O, Perlegos AE, Byrns CN, Carranza FR, Zhou HW, Kim HJ, Zhu Y, Bonini NM. Toxicity of pathogenic ataxin-2 in Drosophila shows dependence on a pure CAG repeat sequence. Hum Mol Genet 2021; 30:1797-1810. [PMID: 34077532 PMCID: PMC8444453 DOI: 10.1093/hmg/ddab148] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 12/31/2022] Open
Abstract
Spinocerebellar ataxia type 2 is a polyglutamine (polyQ) disease associated with an expanded polyQ domain within the protein product of the ATXN2 gene. Interestingly, polyQ repeat expansions in ATXN2 are also associated with amyotrophic lateral sclerosis (ALS) and parkinsonism depending upon the length of the polyQ repeat expansion. The sequence encoding the polyQ repeat also varies with disease presentation: a pure CAG repeat is associated with SCA2, whereas the CAG repeat in ALS and parkinsonism is typically interrupted with the glutamine encoding CAA codon. Here, we asked if the purity of the CAG sequence encoding the polyQ repeat in ATXN2 could impact the toxicity of the ataxin-2 protein in vivo in Drosophila. We found that ataxin-2 encoded by a pure CAG repeat conferred toxicity in the retina and nervous system, whereas ataxin-2 encoded by a CAA-interrupted repeat or CAA-only repeat failed to confer toxicity, despite expression of the protein at similar levels. Furthermore, the CAG-encoded ataxin-2 protein aggregated in the fly eye, while ataxin-2 encoded by either a CAA/G or CAA repeat remained diffuse. The toxicity of the CAG-encoded ataxin-2 protein was also sensitive to the translation factor eIF4H, a known modifier of the toxic GGGGCC repeat in flies. These data indicate that ataxin-2 encoded by a pure CAG versus interrupted CAA/G polyQ repeat domain is associated with differential toxicity, indicating that mechanisms associated with the purity of the sequence of the polyQ domain contribute to disease.
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Affiliation(s)
- Leeanne McGurk
- Division of Cell & Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Olivia M Rifai
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - China N Byrns
- Neurosciences Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
- Medical Sciences Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Faith R Carranza
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Henry W Zhou
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hyung-Jun Kim
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yongqing Zhu
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Neurosciences Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
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45
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Molecular Pathogenesis and Peripheral Monitoring of Adult Fragile X-Associated Syndromes. Int J Mol Sci 2021; 22:ijms22168368. [PMID: 34445074 PMCID: PMC8395059 DOI: 10.3390/ijms22168368] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/16/2022] Open
Abstract
Abnormal trinucleotide expansions cause rare disorders that compromise quality of life and, in some cases, lifespan. In particular, the expansions of the CGG-repeats stretch at the 5’-UTR of the Fragile X Mental Retardation 1 (FMR1) gene have pleiotropic effects that lead to a variety of Fragile X-associated syndromes: the neurodevelopmental Fragile X syndrome (FXS) in children, the late-onset neurodegenerative disorder Fragile X-associated tremor-ataxia syndrome (FXTAS) that mainly affects adult men, the Fragile X-associated primary ovarian insufficiency (FXPOI) in adult women, and a variety of psychiatric and affective disorders that are under the term of Fragile X-associated neuropsychiatric disorders (FXAND). In this review, we will describe the pathological mechanisms of the adult “gain-of-function” syndromes that are mainly caused by the toxic actions of CGG RNA and FMRpolyG peptide. There have been intensive attempts to identify reliable peripheral biomarkers to assess disease progression and onset of specific pathological traits. Mitochondrial dysfunction, altered miRNA expression, endocrine system failure, and impairment of the GABAergic transmission are some of the affectations that are susceptible to be tracked using peripheral blood for monitoring of the motor, cognitive, psychiatric and reproductive impairment of the CGG-expansion carriers. We provided some illustrative examples from our own cohort. Understanding the association between molecular pathogenesis and biomarkers dynamics will improve effective prognosis and clinical management of CGG-expansion carriers.
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46
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Pandya N, Bhagwat SR, Kumar A. Regulatory role of Non-canonical DNA Polymorphisms in human genome and their relevance in Cancer. Biochim Biophys Acta Rev Cancer 2021; 1876:188594. [PMID: 34303788 DOI: 10.1016/j.bbcan.2021.188594] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 12/17/2022]
Abstract
DNA has the ability to form polymorphic structures like canonical duplex DNA and non-canonical triplex DNA, Cruciform, Z-DNA, G-quadruplex (G4), i-motifs, and hairpin structures. The alteration in the form of DNA polymorphism in the response to environmental changes influences the gene expression. Non-canonical structures are engaged in various biological functions, including chromatin epigenetic and gene expression regulation via transcription and translation, as well as DNA repair and recombination. The presence of non-canonical structures in the regulatory region of the gene alters the gene expression and affects the cellular machinery. Formation of non-canonical structure in the regulatory site of cancer-related genes either inhibits or dysregulate the gene function and promote tumour formation. In the current article, we review the influence of non-canonical structure on the regulatory mechanisms in human genome. Moreover, we have also discussed the relevance of non-canonical structures in cancer and provided information on the drugs used for their treatment by targeting these structures.
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Affiliation(s)
- Nirali Pandya
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Sonali R Bhagwat
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India.
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47
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Simeth NA, Kobayashi S, Kobauri P, Crespi S, Szymanski W, Nakatani K, Dohno C, Feringa BL. Rational design of a photoswitchable DNA glue enabling high regulatory function and supramolecular chirality transfer. Chem Sci 2021; 12:9207-9220. [PMID: 34276952 PMCID: PMC8261765 DOI: 10.1039/d1sc02194j] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 05/22/2021] [Indexed: 01/02/2023] Open
Abstract
Short, complementary DNA single strands with mismatched base pairs cannot undergo spontaneous formation of duplex DNA (dsDNA). Mismatch binding ligands (MBLs) can compensate this effect, inducing the formation of the double helix and thereby acting as a molecular glue. Here, we present the rational design of photoswitchable MBLs that allow for reversible dsDNA assembly by light. Careful choice of the azobenzene core structure results in excellent band separation of the E and Z isomers of the involved chromophores. This effect allows for efficient use of light as an external control element for duplex DNA formation and for an in-depth study of the DNA-ligand interaction by UV-Vis, SPR, and CD spectroscopy, revealing a tight mutual interaction and complementarity between the photoswitchable ligand and the mismatched DNA. We also show that the configuration of the switch reversibly dictates the conformation of the DNA strands, while the dsDNA serves as a chiral clamp and translates its chiral information onto the ligand inducing a preference in helical chirality of the Z isomer of the MBLs.
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Affiliation(s)
- Nadja A Simeth
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Shotaro Kobayashi
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Piermichele Kobauri
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Stefano Crespi
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Wiktor Szymanski
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
- Department of Radiology, Medical Imaging Center, University of Groningen, University Medical Centre Groningen Hanzeplein 1 9713 GZ Groningen The Netherlands
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Chikara Dohno
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Ben L Feringa
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, Faculty for Science and Engineering, University of Groningen Nijenborgh 4 9747 AG Groningen The Netherlands
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48
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Porro A, Mohiuddin M, Zurfluh C, Spegg V, Dai J, Iehl F, Ropars V, Collotta G, Fishwick KM, Mozaffari NL, Guérois R, Jiricny J, Altmeyer M, Charbonnier JB, Pearson CE, Sartori AA. FAN1-MLH1 interaction affects repair of DNA interstrand cross-links and slipped-CAG/CTG repeats. SCIENCE ADVANCES 2021; 7:7/31/eabf7906. [PMID: 34330701 PMCID: PMC8324060 DOI: 10.1126/sciadv.abf7906] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 06/15/2021] [Indexed: 05/05/2023]
Abstract
FAN1, a DNA structure-specific nuclease, interacts with MLH1, but the repair pathways in which this complex acts are unknown. FAN1 processes DNA interstrand crosslinks (ICLs) and FAN1 variants are modifiers of the neurodegenerative Huntington's disease (HD), presumably by regulating HD-causing CAG repeat expansions. Here, we identify specific amino acid residues in two adjacent FAN1 motifs that are critical for MLH1 binding. Disruption of the FAN1-MLH1 interaction confers cellular hypersensitivity to ICL damage and defective repair of CAG/CTG slip-outs, intermediates of repeat expansion mutations. FAN1-S126 phosphorylation, which hinders FAN1-MLH1 association, is cell cycle-regulated by cyclin-dependent kinase activity and attenuated upon ICL induction. Our data highlight the FAN1-MLH1 complex as a phosphorylation-regulated determinant of ICL response and repeat stability, opening novel paths to modify cancer and neurodegeneration.
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Affiliation(s)
- Antonio Porro
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Mohiuddin Mohiuddin
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Christina Zurfluh
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Vincent Spegg
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Jingqi Dai
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Florence Iehl
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Virginie Ropars
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Giulio Collotta
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Keri M Fishwick
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Nour L Mozaffari
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Raphaël Guérois
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Josef Jiricny
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Matthias Altmeyer
- Department of Molecular Mechanisms of Disease, University of Zurich, Zurich, Switzerland
| | - Jean-Baptiste Charbonnier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Christopher E Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.
- Program of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Alessandro A Sartori
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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49
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Oura S, Noda T, Morimura N, Hitoshi S, Nishimasu H, Nagai Y, Nureki O, Ikawa M. Precise CAG repeat contraction in a Huntington's Disease mouse model is enabled by gene editing with SpCas9-NG. Commun Biol 2021; 4:771. [PMID: 34163001 PMCID: PMC8222283 DOI: 10.1038/s42003-021-02304-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 06/03/2021] [Indexed: 12/22/2022] Open
Abstract
The clustered regularly interspaced palindromic repeats (CRISPR)/Cas9 system is a research hotspot in gene therapy. However, the widely used Streptococcus pyogenes Cas9 (WT-SpCas9) requires an NGG protospacer adjacent motif (PAM) for target recognition, thereby restricting targetable disease mutations. To address this issue, we recently reported an engineered SpCas9 nuclease variant (SpCas9-NG) recognizing NGN PAMs. Here, as a feasibility study, we report SpCas9-NG-mediated repair of the abnormally expanded CAG repeat tract in Huntington's disease (HD). By targeting the boundary of CAG repeats with SpCas9-NG, we precisely contracted the repeat tracts in HD-mouse-derived embryonic stem (ES) cells. Further, we confirmed the recovery of phenotypic abnormalities in differentiated neurons and animals produced from repaired ES cells. Our study shows that SpCas9-NG can be a powerful tool for repairing abnormally expanded CAG repeats as well as other disease mutations that are difficult to access with WT-SpCas9.
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Affiliation(s)
- Seiya Oura
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Taichi Noda
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
- Division of Reproductive Biology, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Naoko Morimura
- Department of Integrative Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Seiji Hitoshi
- Department of Integrative Physiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Hiroshi Nishimasu
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Department of Structural Biology, Research center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Yoshitaka Nagai
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
- Department of Neurotherapeutics, Osaka University Graduate School of Medicine, Osaka, Japan
- Department of Neurology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Masahito Ikawa
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan.
- Laboratory of Reproductive Systems Biology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
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50
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Replication-independent instability of Friedreich's ataxia GAA repeats during chronological aging. Proc Natl Acad Sci U S A 2021; 118:2013080118. [PMID: 33495349 PMCID: PMC7865128 DOI: 10.1073/pnas.2013080118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The inheritance of long (GAA)n repeats in the frataxin gene causes the debilitating neurodegenerative disease Friedreich’s ataxia. Subsequent expansions of these repeats throughout a patient’s lifetime in the affected tissues, like the nervous system, may contribute to disease onset. We developed an experimental model to characterize the mechanisms of repeat instability in nondividing cells to better understand how mutations can occur as cells age chronologically. We show that repeats can expand in nondividing cells. Notably, however, large deletions are the major type of repeat-mediated genome instability in nondividing cells, implicating the loss of important genetic material with aging in the progression of Friedreich’s ataxia. Nearly 50 hereditary diseases result from the inheritance of abnormally long repetitive DNA microsatellites. While it was originally believed that the size of inherited repeats is the key factor in disease development, it has become clear that somatic instability of these repeats throughout an individual’s lifetime strongly contributes to disease onset and progression. Importantly, somatic instability is commonly observed in terminally differentiated, postmitotic cells, such as neurons. To unravel the mechanisms of repeat instability in nondividing cells, we created an experimental system to analyze the mutability of Friedreich’s ataxia (GAA)n repeats during chronological aging of quiescent Saccharomyces cerevisiae. Unexpectedly, we found that the predominant repeat-mediated mutation in nondividing cells is large-scale deletions encompassing parts, or the entirety, of the repeat and adjacent regions. These deletions are caused by breakage at the repeat mediated by mismatch repair (MMR) complexes MutSβ and MutLα and DNA endonuclease Rad1, followed by end-resection by Exo1 and repair of the resulting double-strand breaks (DSBs) via nonhomologous end joining. We also observed repeat-mediated gene conversions as a result of DSB repair via ectopic homologous recombination during chronological aging. Repeat expansions accrue during chronological aging as well—particularly in the absence of MMR-induced DSBs. These expansions depend on the processivity of DNA polymerase δ while being counteracted by Exo1 and MutSβ, implicating nick repair. Altogether, these findings show that the mechanisms and types of (GAA)n repeat instability differ dramatically between dividing and nondividing cells, suggesting that distinct repeat-mediated mutations in terminally differentiated somatic cells might influence Friedreich’s ataxia pathogenesis.
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