1
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O'Brien BM, Moulick R, Jiménez-Avalos G, Rajasekaran N, Kaiser CM, Woodson SA. Stick-slip unfolding favors self-association of expanded HTT mRNA. Nat Commun 2024; 15:8738. [PMID: 39384800 PMCID: PMC11464812 DOI: 10.1038/s41467-024-52764-x] [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: 02/15/2024] [Accepted: 09/14/2024] [Indexed: 10/11/2024] Open
Abstract
In Huntington's Disease (HD) and related disorders, expansion of CAG trinucleotide repeats produces a toxic gain of function in affected neurons. Expanded huntingtin (expHTT) mRNA forms aggregates that sequester essential RNA binding proteins, dysregulating mRNA processing and translation. The physical basis of RNA aggregation has been difficult to disentangle owing to the heterogeneous structure of the CAG repeats. Here, we probe the folding and unfolding pathways of expHTT mRNA using single-molecule force spectroscopy. Whereas normal HTT mRNAs unfold reversibly and cooperatively, expHTT mRNAs with 20 or 40 CAG repeats slip and unravel non-cooperatively at low tension. Slippage of CAG base pairs is punctuated by concerted rearrangement of adjacent CCG trinucleotides, trapping partially folded structures that readily base pair with another RNA strand. We suggest that the conformational entropy of the CAG repeats, combined with stable CCG base pairs, creates a stick-slip behavior that explains the aggregation propensity of expHTT mRNA.
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Affiliation(s)
- Brett M O'Brien
- Chemical Biology Interface Program, Johns Hopkins University, Baltimore, MD, USA
| | - Roumita Moulick
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Christian M Kaiser
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA.
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
| | - Sarah A Woodson
- Chemical Biology Interface Program, Johns Hopkins University, Baltimore, MD, USA.
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA.
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2
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O'Brien BM, Moulick R, Jiménez-Avalos G, Rajasekaran N, Kaiser CM, Woodson SA. Stick-slip unfolding favors self-association of expanded HTT mRNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.31.596809. [PMID: 38895475 PMCID: PMC11185545 DOI: 10.1101/2024.05.31.596809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
In Huntington's Disease (HD) and related disorders, expansion of CAG trinucleotide repeats produces a toxic gain of function in affected neurons. Expanded huntingtin (expHTT) mRNA forms aggregates that sequester essential RNA binding proteins, dysregulating mRNA processing and translation. The physical basis of RNA aggregation has been difficult to disentangle owing to the heterogeneous structure of the CAG repeats. Here, we probe the folding and unfolding pathways of expHTT mRNA using single-molecule force spectroscopy. Whereas normal HTT mRNAs unfold reversibly and cooperatively, expHTT mRNAs with 20 or 40 CAG repeats slip and unravel non-cooperatively at low tension. Slippage of CAG base pairs is punctuated by concerted rearrangement of adjacent CCG trinucleotides, trapping partially folded structures that readily base pair with another RNA strand. We suggest that the conformational entropy of the CAG repeats, combined with stable CCG base pairs, creates a stick-slip behavior that explains the aggregation propensity of expHTT mRNA.
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Affiliation(s)
- Brett M O'Brien
- Chemical Biology Interface Program, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Roumita Moulick
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Gabriel Jiménez-Avalos
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| | | | - Christian M Kaiser
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218 USA
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | - Sarah A Woodson
- Chemical Biology Interface Program, Johns Hopkins University, Baltimore, MD 21218 USA
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
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3
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Maity H, Nguyen HT, Hori N, Thirumalai D. Salt-Dependent Self-Association of Trinucleotide Repeat RNA Sequences. J Phys Chem Lett 2024; 15:3820-3827. [PMID: 38557079 DOI: 10.1021/acs.jpclett.3c03553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Repeat RNA sequences self-associate to form condensates. Simulations of a coarse-grained single-interaction site model for (CAG)n (n = 30 and 31) show that the salt-dependent free energy gap, ΔGS, between the ground (perfect hairpin) and the excited state (slipped hairpin (SH) with one CAG overhang) of the monomer for (n even) is the primary factor that determines the rates and yield of self-assembly. For odd n, the free energy (GS) of the ground state, which is an SH, is used to predict the self-association kinetics. As the monovalent salt concentration, CS, increases, ΔGS and GS increase, which decreases the rates of dimer formation. In contrast, ΔGS for shuffled sequences, with the same length and sequence composition as (CAG)31, is larger, which suppresses their propensities to aggregate. Although demonstrated explicitly for (CAG) polymers, the finding of inverse correlation between the free energy gap and RNA aggregation is general.
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Affiliation(s)
- Hiranmay Maity
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Hung T Nguyen
- Department of Chemistry, The State University of New York at Buffalo, Buffalo, New York 14260, United States
| | - Naoto Hori
- School of Pharmacy, University of Nottingham, Nottingham NG72RD, United Kingdom
| | - D Thirumalai
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
- Department of Physics, University of Texas at Austin, Austin, Texas 78712, United States
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4
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Richardson K, Sengupta M, Sujkowski A, Libohova K, Harris AC, Wessells R, Merry DE, Todi SV. A phenotypically robust model of spinal and bulbar muscular atrophy in Drosophila. J Neurosci Res 2024; 102:e25278. [PMID: 38284836 PMCID: PMC11237963 DOI: 10.1002/jnr.25278] [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: 07/19/2023] [Revised: 10/14/2023] [Accepted: 11/05/2023] [Indexed: 01/30/2024]
Abstract
Spinal and bulbar muscular atrophy (SBMA) is an X-linked disorder that affects males who inherit the androgen receptor (AR) gene with an abnormal CAG triplet repeat expansion. The resulting protein contains an elongated polyglutamine (polyQ) tract and causes motor neuron degeneration in an androgen-dependent manner. The precise molecular sequelae of SBMA are unclear. To assist with its investigation and the identification of therapeutic options, we report here a new model of SBMA in Drosophila melanogaster. We generated transgenic flies that express the full-length, human AR with a wild-type or pathogenic polyQ repeat. Each transgene is inserted into the same safe harbor site on the third chromosome of the fly as a single copy and in the same orientation. Expression of pathogenic AR, but not of its wild-type variant, in neurons or muscles leads to consistent, progressive defects in longevity and motility that are concomitant with polyQ-expanded AR protein aggregation and reduced complexity in neuromuscular junctions. Additional assays show adult fly eye abnormalities associated with the pathogenic AR species. The detrimental effects of pathogenic AR are accentuated by feeding flies the androgen, dihydrotestosterone. This new, robust SBMA model can be a valuable tool toward future investigations of this incurable disease.
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Affiliation(s)
- Kristin Richardson
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Medha Sengupta
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Alyson Sujkowski
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Autumn C Harris
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Maximizing Access to Science Careers Program, Wayne State University, Detroit, Michigan, USA
| | - Robert Wessells
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Diane E Merry
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Maximizing Access to Science Careers Program, Wayne State University, Detroit, Michigan, USA
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
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5
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Kumar M, Tyagi N, Faruq M. The molecular mechanisms of spinocerebellar ataxias for DNA repeat expansion in disease. Emerg Top Life Sci 2023; 7:289-312. [PMID: 37668011 DOI: 10.1042/etls20230013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 09/06/2023]
Abstract
Spinocerebellar ataxias (SCAs) are a heterogenous group of neurodegenerative disorders which commonly inherited in an autosomal dominant manner. They cause muscle incoordination due to degeneration of the cerebellum and other parts of nervous system. Out of all the characterized (>50) SCAs, 14 SCAs are caused due to microsatellite repeat expansion mutations. Repeat expansions can result in toxic protein gain-of-function, protein loss-of-function, and/or RNA gain-of-function effects. The location and the nature of mutation modulate the underlying disease pathophysiology resulting in varying disease manifestations. Potential toxic effects of these mutations likely affect key major cellular processes such as transcriptional regulation, mitochondrial functioning, ion channel dysfunction and synaptic transmission. Involvement of several common pathways suggests interlinked function of genes implicated in the disease pathogenesis. A better understanding of the shared and distinct molecular pathogenic mechanisms in these diseases is required to develop targeted therapeutic tools and interventions for disease management. The prime focus of this review is to elaborate on how expanded 'CAG' repeats contribute to the common modes of neurotoxicity and their possible therapeutic targets in management of such devastating disorders.
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Affiliation(s)
- Manish Kumar
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
| | - Nishu Tyagi
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
| | - Mohammed Faruq
- CSIR-Institute of Genomics and Integrative Biology, Mall Road, Delhi 110007, India
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6
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Soueid DM, Garner AL. Adaptation of RiPCA for the Live-Cell Detection of mRNA-Protein Interactions. Biochemistry 2023; 62:3323-3336. [PMID: 37963240 PMCID: PMC11466511 DOI: 10.1021/acs.biochem.3c00334] [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] [Indexed: 11/16/2023]
Abstract
RNA-binding proteins (RBPs) act as essential regulators of cell fate decisions, through their ability to bind and regulate the activity of cellular RNAs. For protein-coding mRNAs, RBPs control the localization, stability, degradation, and ultimately translation of mRNAs to impact gene expression. Disruption of the vast network of mRNA-protein interactions has been implicated in many human diseases, and accordingly, targeting these interactions has surfaced as a new frontier in RNA-targeted drug discovery. To catalyze this new field, methods are needed to enable the detection and subsequent screening of mRNA-RBP interactions, particularly in live cells. Using our laboratory's RNA-interaction with Protein-mediated Complementation Assay (RiPCA) technology, herein we describe its application to mRNA-protein interactions and present a guide for the development of future RiPCA assays for structurally diverse classes of mRNA-protein interactions.
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Affiliation(s)
- Dalia M. Soueid
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Amanda L. Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
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7
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Shino A, Otsu M, Imai K, Fukuzawa K, Morishita EC. Probing RNA-Small Molecule Interactions Using Biophysical and Computational Approaches. ACS Chem Biol 2023; 18:2368-2376. [PMID: 37856793 PMCID: PMC10662358 DOI: 10.1021/acschembio.3c00287] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/30/2023] [Indexed: 10/21/2023]
Abstract
Interest in small molecules that target RNA is flourishing, and the expectation set on them to treat diseases with unmet medical needs is high. However, several challenges remain, including difficulties in selecting suitable tools and establishing workflows for their discovery. In this context, we optimized experimental and computational approaches that were previously employed for the protein targets. Here, we demonstrate that a fluorescence-based assay can be effectively used to screen small molecule libraries for their ability to bind and stabilize an RNA stem-loop. Our screen identified several fluoroquinolones that bind to the target stem-loop. We further probed their interactions with the target using biolayer interferometry, isothermal titration calorimetry (ITC), and nuclear magnetic resonance spectroscopy. The results of these biophysical assays suggest that the fluoroquinolones bind the target in a similar manner. Armed with this knowledge, we built models for the complexes of the fluoroquinolones and the RNA target. Then, we performed fragment molecular orbital (FMO) calculations to dissect the interactions between the fluoroquinolones and the RNA. We found that the binding free energies obtained from the ITC experiments correlated strongly with the interaction energies calculated by FMO. Finally, we designed fluoroquinolone analogues and performed FMO calculations to predict their binding free energies. Taken together, the results of this study support the importance of conducting orthogonal assays in binding confirmation and compound selection and demonstrate the usefulness of FMO calculations in the rational design of RNA-targeted small molecules.
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Affiliation(s)
- Amiu Shino
- Basic
Research Division, Veritas In Silico Inc., Shinagawa, Tokyo 141-0031, Japan
| | - Maina Otsu
- Basic
Research Division, Veritas In Silico Inc., Shinagawa, Tokyo 141-0031, Japan
| | - Koji Imai
- Basic
Research Division, Veritas In Silico Inc., Shinagawa, Tokyo 141-0031, Japan
| | - Kaori Fukuzawa
- Graduate
School of Pharmaceutical Sciences, Osaka
University, Suita, Osaka 565-0871, Japan
- School
of Pharmacy and Pharmaceutical Sciences, Hoshi University, Shinagawa, Tokyo 142-8501, Japan
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8
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Gibaut QR, Bush JA, Tong Y, Baisden JT, Taghavi A, Olafson H, Yao X, Childs-Disney JL, Wang ET, Disney MD. Transcriptome-Wide Studies of RNA-Targeted Small Molecules Provide a Simple and Selective r(CUG) exp Degrader in Myotonic Dystrophy. ACS CENTRAL SCIENCE 2023; 9:1342-1353. [PMID: 37521782 PMCID: PMC10375898 DOI: 10.1021/acscentsci.2c01223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Indexed: 08/01/2023]
Abstract
Myotonic dystrophy type 1 (DM1) is caused by a highly structured RNA repeat expansion, r(CUG)exp, harbored in the 3' untranslated region (3' UTR) of dystrophia myotonica protein kinase (DMPK) mRNA and drives disease through a gain-of-function mechanism. A panel of low-molecular-weight fragments capable of reacting with RNA upon UV irradiation was studied for cross-linking to r(CUG)expin vitro, affording perimidin-2-amine diazirine (1) that bound to r(CUG)exp. The interactions between the small molecule and RNA were further studied by nuclear magnetic resonance (NMR) spectroscopy and molecular modeling. Binding of 1 in DM1 myotubes was profiled transcriptome-wide, identifying 12 transcripts including DMPK that were bound by 1. Augmenting the functionality of 1 with cleaving capability created a chimeric degrader that specifically targets r(CUG)exp for elimination. The degrader broadly improved DM1-associated defects as assessed by RNA-seq, while having limited effects on healthy myotubes. This study (i) provides a platform to investigate molecular recognition of ligands directly in disease-affected cells; (ii) illustrates that RNA degraders can be more specific than the binders from which they are derived; and (iii) suggests that repeating transcripts can be selectively degraded due to the presence of multiple ligand binding sites.
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Affiliation(s)
- Quentin
M. R. Gibaut
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Jessica A. Bush
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Yuquan Tong
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Jared T. Baisden
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Amirhossein Taghavi
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Hailey Olafson
- Center
for NeuroGenetics, University of Florida, Gainesville, Florida 32610, United States
- Department
of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Xiyuan Yao
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Jessica L. Childs-Disney
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Eric T. Wang
- Center
for NeuroGenetics, University of Florida, Gainesville, Florida 32610, United States
- Department
of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Matthew D. Disney
- The
Department of Chemistry, UF Scripps Biomedical
Research and The Scripps Research Institute, Jupiter, Florida 33458, United States
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9
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Maity H, Nguyen HT, Hori N, Thirumalai D. Odd-even disparity in the population of slipped hairpins in RNA repeat sequences with implications for phase separation. Proc Natl Acad Sci U S A 2023; 120:e2301409120. [PMID: 37276412 PMCID: PMC10268303 DOI: 10.1073/pnas.2301409120] [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: 01/25/2023] [Accepted: 05/10/2023] [Indexed: 06/07/2023] Open
Abstract
Low-complexity nucleotide repeat sequences, which are implicated in several neurological disorders, undergo liquid-liquid phase separation (LLPS) provided the number of repeat units, n, exceeds a critical value. Here, we establish a link between the folding landscapes of the monomers of trinucleotide repeats and their propensity to self-associate. Simulations using a coarse-grained Self-Organized Polymer (SOP) model for (CAG)n repeats in monovalent salt solutions reproduce experimentally measured melting temperatures, which are available only for small n. By extending the simulations to large n, we show that the free-energy gap, ΔGS, between the ground state (GS) and slipped hairpin (SH) states is a predictor of aggregation propensity. The GS for even n is a perfect hairpin (PH), whereas it is a SH when n is odd. The value of ΔGS (zero for odd n) is larger for even n than for odd n. As a result, the rate of dimer formation is slower in (CAG)30 relative to (CAG)31, thus linking ΔGS to RNA-RNA association. The yield of the dimer decreases dramatically, compared to the wild type, in mutant sequences in which the population of the SH decreases substantially. Association between RNA chains is preceded by a transition to the SH even if the GS is a PH. The finding that the excitation spectrum-which depends on the exact sequence, n, and ionic conditions-is a predictor of self-association should also hold for other RNAs (mRNA for example) that undergo LLPS.
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Affiliation(s)
- Hiranmay Maity
- Department of Chemistry, The University of Texas at Austin, AustinTX78712
| | - Hung T. Nguyen
- Department of Chemistry, The University of Texas at Austin, AustinTX78712
| | - Naoto Hori
- School of Pharmacy, University of Nottingham, NG7 2rD, United Kingdom
| | - D. Thirumalai
- Department of Chemistry, The University of Texas at Austin, AustinTX78712
- Department of Physics, The University of Texas at Austin, AustinTX78712
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10
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Wright SE, Todd PK. Native functions of short tandem repeats. eLife 2023; 12:e84043. [PMID: 36940239 PMCID: PMC10027321 DOI: 10.7554/elife.84043] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 03/08/2023] [Indexed: 03/21/2023] Open
Abstract
Over a third of the human genome is comprised of repetitive sequences, including more than a million short tandem repeats (STRs). While studies of the pathologic consequences of repeat expansions that cause syndromic human diseases are extensive, the potential native functions of STRs are often ignored. Here, we summarize a growing body of research into the normal biological functions for repetitive elements across the genome, with a particular focus on the roles of STRs in regulating gene expression. We propose reconceptualizing the pathogenic consequences of repeat expansions as aberrancies in normal gene regulation. From this altered viewpoint, we predict that future work will reveal broader roles for STRs in neuronal function and as risk alleles for more common human neurological diseases.
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Affiliation(s)
- Shannon E Wright
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- Neuroscience Graduate Program, University of Michigan–Ann ArborAnn ArborUnited States
- Department of Neuroscience, Picower InstituteCambridgeUnited States
| | - Peter K Todd
- Department of Neurology, University of Michigan–Ann ArborAnn ArborUnited States
- VA Ann Arbor Healthcare SystemAnn ArborUnited States
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11
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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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12
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Uncovering the mechanism for aggregation in repeat expanded RNA reveals a reentrant transition. Nat Commun 2023; 14:332. [PMID: 36658112 PMCID: PMC9852226 DOI: 10.1038/s41467-023-35803-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 12/29/2022] [Indexed: 01/21/2023] Open
Abstract
RNA molecules aggregate under certain conditions. The resulting condensates are implicated in human neurological disorders, and can potentially be designed towards specified bulk properties in vitro. However, the mechanism for aggregation-including how aggregation properties change with sequence and environmental conditions-remains poorly understood. To address this challenge, we introduce an analytical framework based on multimer enumeration. Our approach reveals the driving force for aggregation to be the increased configurational entropy associated with the multiplicity of ways to form bonds in the aggregate. Our model uncovers rich phase behavior, including a sequence-dependent reentrant phase transition, and repeat parity-dependent aggregation. We validate our results by comparison to a complete computational enumeration of the landscape, and to previously published molecular dynamics simulations. Our work unifies and extends published results, both explaining the behavior of CAG-repeat RNA aggregates implicated in Huntington's disease, and enabling the rational design of programmable RNA condensates.
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13
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Morelli KH, Wu Q, Gosztyla ML, Liu H, Yao M, Zhang C, Chen J, Marina RJ, Lee K, Jones KL, Huang MY, Li A, Smith-Geater C, Thompson LM, Duan W, Yeo GW. An RNA-targeting CRISPR-Cas13d system alleviates disease-related phenotypes in Huntington's disease models. Nat Neurosci 2023; 26:27-38. [PMID: 36510111 PMCID: PMC9829537 DOI: 10.1038/s41593-022-01207-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 10/18/2022] [Indexed: 12/14/2022]
Abstract
Huntington's disease (HD) is a fatal, dominantly inherited neurodegenerative disorder caused by CAG trinucleotide expansion in exon 1 of the huntingtin (HTT) gene. Since the reduction of pathogenic mutant HTT messenger RNA is therapeutic, we developed a mutant allele-sensitive CAGEX RNA-targeting CRISPR-Cas13d system (Cas13d-CAGEX) that eliminates toxic CAGEX RNA in fibroblasts derived from patients with HD and induced pluripotent stem cell-derived neurons. We show that intrastriatal delivery of Cas13d-CAGEX via an adeno-associated viral vector selectively reduces mutant HTT mRNA and protein levels in the striatum of heterozygous zQ175 mice, a model of HD. This also led to improved motor coordination, attenuated striatal atrophy and reduction of mutant HTT protein aggregates. These phenotypic improvements lasted for at least eight months without adverse effects and with minimal off-target transcriptomic effects. Taken together, we demonstrate proof of principle of an RNA-targeting CRISPR-Cas13d system as a therapeutic approach for HD, a strategy with implications for the treatment of other dominantly inherited disorders.
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Affiliation(s)
- Kathryn H Morelli
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Qian Wu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Maya L Gosztyla
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Hongshuai Liu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Minmin Yao
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chuangchuang Zhang
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiaxu Chen
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China
| | - Ryan J Marina
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Kari Lee
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Krysten L Jones
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Megan Y Huang
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Allison Li
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Charlene Smith-Geater
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, CA, USA
| | - Leslie M Thompson
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, CA, USA
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA, USA
| | - Wenzhen Duan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- The Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA.
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA.
- Stem Cell Program, University of California San Diego, La Jolla, CA, USA.
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14
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The length of uninterrupted CAG repeats in stem regions of repeat disease associated hairpins determines the amount of short CAG oligonucleotides that are toxic to cells through RNA interference. Cell Death Dis 2022; 13:1078. [PMID: 36585400 PMCID: PMC9803637 DOI: 10.1038/s41419-022-05494-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/31/2022]
Abstract
Extended CAG trinucleotide repeats (TNR) in the genes huntingtin (HTT) and androgen receptor (AR) are the cause of two progressive neurodegenerative disorders: Huntington's disease (HD) and Spinal and Bulbar Muscular Atrophy (SBMA), respectively. Anyone who inherits the mutant gene in the complete penetrance range (>39 repeats for HD and 44 for SBMA) will develop the disease. An inverse correlation exists between the length of the CAG repeat and the severity and age of onset of the diseases. Growing evidence suggests that it is the length of uninterrupted CAG repeats in the mRNA rather than the length of poly glutamine (polyQ) in mutant (m)HTT protein that determines disease progression. One variant of mHTT (loss of inhibition; LOI) causes a 25 year earlier onset of HD when compared to a reference sequence, despite both coding for a protein that contains an identical number of glutamines. Short 21-22 nt CAG repeat (sCAGs)-containing RNAs can cause disease through RNA interference (RNAi). RNA hairpins (HPs) forming at the CAG TNRs are stabilized by adjacent CCG (in HD) or CUG repeats (in SBMA) making them better substrates for Dicer, the enzyme that processes CAG HPs into sCAGs. We now show that cells deficient in Dicer or unable to mediate RNAi are resistant to the toxicity of the HTT and AR derived HPs. Expression of a small HP that mimics the HD LOI variant is more stable and more toxic than a reference HP. We report that the LOI HP is processed by Dicer, loaded into the RISC more efficiently, and gives rise to a higher quantity of RISC-bound 22 nt sCAGs. Our data support the notion that RNAi contributes to the cell death seen in HD and SBMA and provide an explanation for the dramatically reduced onset of disease in HD patients that carry the LOI variant.
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15
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Rosario R, Stewart HL, Choudhury NR, Michlewski G, Charlet‐Berguerand N, Anderson RA. Evidence for a fragile X messenger ribonucleoprotein 1 (FMR1) mRNA gain-of-function toxicity mechanism contributing to the pathogenesis of fragile X-associated premature ovarian insufficiency. FASEB J 2022; 36:e22612. [PMID: 36250920 PMCID: PMC9828574 DOI: 10.1096/fj.202200468rr] [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: 03/25/2022] [Revised: 09/22/2022] [Accepted: 10/03/2022] [Indexed: 01/12/2023]
Abstract
Fragile X-associated premature ovarian insufficiency (FXPOI) is among a family of disorders caused by expansion of a CGG trinucleotide repeat sequence located in the 5' untranslated region (UTR) of the fragile X messenger ribonucleoprotein 1 (FMR1) gene on the X chromosome. Women with FXPOI have a depleted ovarian follicle population, resulting in amenorrhea, hypoestrogenism, and loss of fertility before the age of 40. FXPOI is caused by expansions of the CGG sequence to lengths between 55 and 200 repeats, known as a FMRI premutation, however the mechanism by which the premutation drives disease pathogenesis remains unclear. Two main hypotheses exist, which describe an mRNA toxic gain-of-function mechanism or a protein-based mechanism, where repeat-associated non-AUG (RAN) translation results in the production of an abnormal protein, called FMRpolyG. Here, we have developed an in vitro granulosa cell model of the FMR1 premutation by ectopically expressing CGG-repeat RNA and FMRpolyG protein. We show that expanded CGG-repeat RNA accumulated in intranuclear RNA structures, and these aggregates were able to cause significant granulosa cell death independent of FMRpolyG expression. Using an innovative RNA pulldown, mass spectrometry-based approach we have identified proteins that are specifically sequestered by CGG RNA aggregates in granulosa cells in vitro, and thus may be deregulated as consequence of this interaction. Furthermore, we have demonstrated reduced expression of three proteins identified via our RNA pulldown (FUS, PA2G4 and TRA2β) in ovarian follicles in a FMR1 premutation mouse model. Collectively, these data provide evidence for the contribution of an mRNA gain-of-function mechanism to FXPOI disease biology.
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Affiliation(s)
- Roseanne Rosario
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK,Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Hazel L. Stewart
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
| | | | - Gracjan Michlewski
- Infection MedicineUniversity of EdinburghEdinburghUK,Zhejiang University‐University of Edinburgh InstituteZhejiang UniversityZhejiangP.R. China,Dioscuri Centre for RNA‐Protein Interactions in Human Health and DiseaseInternational Institute of Molecular and Cell Biology in WarsawWarsawPoland
| | - Nicholas Charlet‐Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)INSERM U 1258, CNRS UMR 7104, Université of StrasbourgIllkirchFrance
| | - Richard A. Anderson
- MRC Centre for Reproductive Health, Queen's Medical Research InstituteUniversity of EdinburghEdinburghUK
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16
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Childs-Disney JL, Yang X, Gibaut QMR, Tong Y, Batey RT, Disney MD. Targeting RNA structures with small molecules. Nat Rev Drug Discov 2022; 21:736-762. [PMID: 35941229 PMCID: PMC9360655 DOI: 10.1038/s41573-022-00521-4] [Citation(s) in RCA: 173] [Impact Index Per Article: 86.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2022] [Indexed: 01/07/2023]
Abstract
RNA adopts 3D structures that confer varied functional roles in human biology and dysfunction in disease. Approaches to therapeutically target RNA structures with small molecules are being actively pursued, aided by key advances in the field including the development of computational tools that predict evolutionarily conserved RNA structures, as well as strategies that expand mode of action and facilitate interactions with cellular machinery. Existing RNA-targeted small molecules use a range of mechanisms including directing splicing - by acting as molecular glues with cellular proteins (such as branaplam and the FDA-approved risdiplam), inhibition of translation of undruggable proteins and deactivation of functional structures in noncoding RNAs. Here, we describe strategies to identify, validate and optimize small molecules that target the functional transcriptome, laying out a roadmap to advance these agents into the next decade.
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Affiliation(s)
| | - Xueyi Yang
- Department of Chemistry, Scripps Research, Jupiter, FL, USA
| | | | - Yuquan Tong
- Department of Chemistry, Scripps Research, Jupiter, FL, USA
| | - Robert T Batey
- Department of Biochemistry, University of Colorado, Boulder, CO, USA.
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17
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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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18
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An Y, Chen ZS, Chan H, Ngo J. Molecular insights into the interaction of CAG trinucleotide RNA repeats with nucleolin and its implication in polyglutamine diseases. Nucleic Acids Res 2022; 50:7655-7668. [PMID: 35776134 PMCID: PMC9303306 DOI: 10.1093/nar/gkac532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/08/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Polyglutamine (polyQ) diseases are a type of inherited neurodegenerative disorders caused by cytosine-adenine-guanine (CAG) trinucleotide expansion within the coding region of the disease-associated genes. We previously demonstrated that a pathogenic interaction between expanded CAG RNA and the nucleolin (NCL) protein triggers the nucleolar stress and neuronal cell death in polyQ diseases. However, mechanisms behind the molecular interaction remain unknown. Here, we report a 1.45 Å crystal structure of the r(CAG)5 oligo that comprises a full A'-form helical turn with widened grooves. Based on this structure, we simulated a model of r(CAG)5 RNA complexed with the RNA recognition motif 2 (RRM2) of NCL and identified NCL residues that are critical for its binding to CAG RNA. Combined with in vitro and in vivo site-directed mutagenesis studies, our model reveals that CAG RNA binds to NCL sites that are not important for other cellular functions like gene expression and rRNA synthesis regulation, indicating that toxic CAG RNA interferes with NCL functions by sequestering it. Accordingly, an NCL mutant that is aberrant in CAG RNA-binding could rescue RNA-induced cytotoxicity effectively. Taken together, our study provides new molecular insights into the pathogenic mechanism of polyQ diseases mediated by NCL-CAG RNA interaction.
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Affiliation(s)
- Ying An
- School of Life Sciences, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
| | - Zhefan S Chen
- School of Life Sciences, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
| | - Ho Yin Edwin Chan
- School of Life Sciences, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
- Gerald Choa Neuroscience Centre, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
| | - Jacky Chi Ki Ngo
- School of Life Sciences, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
- Center for Novel Biomaterials, The Chinese University of Hong Kong, Shatin N.T., Hong Kong SAR, China
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19
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Haruehanroengra P, Zheng YY, Ma G, Lan TH, Hassan AEA, Zhou Y, Sheng J. Probing the Substrate Requirements of the in vitro Geranylation Activity of Selenouridine Synthase (SelU). Chembiochem 2022; 23:e202200089. [DOI: 10.1002/cbic.202200089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 05/31/2022] [Indexed: 11/10/2022]
Affiliation(s)
| | - Ya Ying Zheng
- University at Albany Chemistry 1400 Washington Ave.Life Science 2033B 12222 Albany UNITED STATES
| | - Guolin Ma
- Texas A&M University System Health Science Center College of Medicine: Texas A&M University College of Medicine Bioscience and Technology UNITED STATES
| | - Tien-Hung Lan
- Texas A&M University System Health Science Center College of Medicine: Texas A&M University College of Medicine Bioscience and Technology UNITED STATES
| | | | - Yubin Zhou
- Texas A&M University System Health Science Center College of Medicine: Texas A&M University College of Medicine Bioscience and Technology UNITED STATES
| | - Jia Sheng
- University at Albany State University of New York Chemistry 1400 Washington Ave.LSRB 2033B 12222 Albany UNITED STATES
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20
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Johnson SL, Prifti MV, Sujkowski A, Libohova K, Blount JR, Hong L, Tsou WL, Todi SV. Drosophila as a Model of Unconventional Translation in Spinocerebellar Ataxia Type 3. Cells 2022; 11:cells11071223. [PMID: 35406787 PMCID: PMC8997593 DOI: 10.3390/cells11071223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 03/29/2022] [Accepted: 03/31/2022] [Indexed: 12/21/2022] Open
Abstract
RNA toxicity contributes to diseases caused by anomalous nucleotide repeat expansions. Recent work demonstrated RNA-based toxicity from repeat-associated, non-AUG-initiated translation (RAN translation). RAN translation occurs around long nucleotide repeats that form hairpin loops, allowing for translation initiation in the absence of a start codon that results in potentially toxic, poly-amino acid repeat-containing proteins. Discovered in Spinocerebellar Ataxia Type (SCA) 8, RAN translation has been documented in several repeat-expansion diseases, including in the CAG repeat-dependent polyglutamine (polyQ) disorders. The ATXN3 gene, which causes SCA3, also known as Machado–Joseph Disease (MJD), contains a CAG repeat that is expanded in disease. ATXN3 mRNA possesses features linked to RAN translation. In this paper, we examined the potential contribution of RAN translation to SCA3/MJD in Drosophila by using isogenic lines that contain homomeric or interrupted CAG repeats. We did not observe unconventional translation in fly neurons or glia. However, our investigations indicate differential toxicity from ATXN3 protein-encoding mRNA that contains pure versus interrupted CAG repeats. Additional work suggests that this difference may be due in part to toxicity from homomeric CAG mRNA. We conclude that Drosophila is not suitable to model RAN translation for SCA3/MJD, but offers clues into the potential pathogenesis stemming from CAG repeat-containing mRNA in this disorder.
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Affiliation(s)
- Sean L. Johnson
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Matthew V. Prifti
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Alyson Sujkowski
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Jessica R. Blount
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Luke Hong
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Wei-Ling Tsou
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
| | - Sokol V. Todi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA; (S.L.J.); (M.V.P.); (A.S.); (K.L.); (J.R.B.); (L.H.); (W.-L.T.)
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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21
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Bush JA, Aikawa H, Fuerst R, Li Y, Ursu A, Meyer SM, Benhamou RI, Chen JL, Khan T, Wagner-Griffin S, Van Meter MJ, Tong Y, Olafson H, McKee KK, Childs-Disney JL, Gendron TF, Zhang Y, Coyne AN, Wang ET, Yildirim I, Wang KW, Petrucelli L, Rothstein JD, Disney MD. Ribonuclease recruitment using a small molecule reduced c9ALS/FTD r(G 4C 2) repeat expansion in vitro and in vivo ALS models. Sci Transl Med 2021; 13:eabd5991. [PMID: 34705518 DOI: 10.1126/scitranslmed.abd5991] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Jessica A Bush
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Haruo Aikawa
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Rita Fuerst
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Yue Li
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Andrei Ursu
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Samantha M Meyer
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Raphael I Benhamou
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Jonathan L Chen
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Tanya Khan
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Sarah Wagner-Griffin
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Montina J Van Meter
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Yuquan Tong
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Hailey Olafson
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Kendra K McKee
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jessica L Childs-Disney
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Yongjie Zhang
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Alyssa N Coyne
- Robert Packard Center for ALS Research, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Eric T Wang
- Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Ilyas Yildirim
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Kye Won Wang
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, FL 33458, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Jeffrey D Rothstein
- Robert Packard Center for ALS Research, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Matthew D Disney
- Department of Chemistry, Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, USA
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22
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Heinz A, Schilling J, van Roon-Mom W, Krauß S. The MID1 Protein: A Promising Therapeutic Target in Huntington's Disease. Front Genet 2021; 12:761714. [PMID: 34659371 PMCID: PMC8517220 DOI: 10.3389/fgene.2021.761714] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is caused by an expansion mutation of a CAG repeat in exon 1 of the huntingtin (HTT) gene, that encodes an expanded polyglutamine tract in the HTT protein. HD is characterized by progressive psychiatric and cognitive symptoms associated with a progressive movement disorder. HTT is ubiquitously expressed, but the pathological changes caused by the mutation are most prominent in the central nervous system. Since the mutation was discovered, research has mainly focused on the mutant HTT protein. But what if the polyglutamine protein is not the only cause of the neurotoxicity? Recent studies show that the mutant RNA transcript is also involved in cellular dysfunction. Here we discuss the abnormal interaction of the mutant HTT transcript with a protein complex containing the MID1 protein. MID1 aberrantly binds to CAG repeats and this binding increases with CAG repeat length. Since MID1 is a translation regulator, association of the MID1 complex stimulates translation of mutant HTT mRNA, resulting in an overproduction of polyglutamine protein. Thus, blocking the interaction between MID1 and mutant HTT mRNA is a promising therapeutic approach. Additionally, we show that MID1 expression in the brain of both HD patients and HD mice is aberrantly increased. This finding further supports the concept of blocking the interaction between MID1 and mutant HTT mRNA to counteract mutant HTT translation as a valuable therapeutic strategy. In line, recent studies in which either compounds affecting the assembly of the MID1 complex or molecules targeting HTT RNA, show promising results.
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Affiliation(s)
- Annika Heinz
- University of Siegen, Institute of Biology, Human Biology / Neurobiology, Siegen, Germany
| | - Judith Schilling
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Willeke van Roon-Mom
- Leiden University Medical Center, Department of Human Genetics, Leiden, Netherlands
| | - Sybille Krauß
- University of Siegen, Institute of Biology, Human Biology / Neurobiology, Siegen, Germany
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23
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Zhao X, Usdin K. (Dys)function Follows Form: Nucleic Acid Structure, Repeat Expansion, and Disease Pathology in FMR1 Disorders. Int J Mol Sci 2021; 22:ijms22179167. [PMID: 34502075 PMCID: PMC8431139 DOI: 10.3390/ijms22179167] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/26/2022] Open
Abstract
Fragile X-related disorders (FXDs), also known as FMR1 disorders, are examples of repeat expansion diseases (REDs), clinical conditions that arise from an increase in the number of repeats in a disease-specific microsatellite. In the case of FXDs, the repeat unit is CGG/CCG and the repeat tract is located in the 5' UTR of the X-linked FMR1 gene. Expansion can result in neurodegeneration, ovarian dysfunction, or intellectual disability depending on the number of repeats in the expanded allele. A growing body of evidence suggests that the mutational mechanisms responsible for many REDs share several common features. It is also increasingly apparent that in some of these diseases the pathologic consequences of expansion may arise in similar ways. It has long been known that many of the disease-associated repeats form unusual DNA and RNA structures. This review will focus on what is known about these structures, the proteins with which they interact, and how they may be related to the causative mutation and disease pathology in the FMR1 disorders.
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Affiliation(s)
- Xiaonan Zhao
- Correspondence: (X.Z.); (K.U.); Tel.: +1-301-451-6322 (X.Z.); +1-301-496-2189 (K.U.)
| | - Karen Usdin
- Correspondence: (X.Z.); (K.U.); Tel.: +1-301-451-6322 (X.Z.); +1-301-496-2189 (K.U.)
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24
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Cheong RY, Baldo B, Sajjad MU, Kirik D, Petersén Å. Effects of mutant huntingtin inactivation on Huntington disease-related behaviours in the BACHD mouse model. Neuropathol Appl Neurobiol 2021; 47:564-578. [PMID: 33330988 PMCID: PMC8247873 DOI: 10.1111/nan.12682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/27/2020] [Accepted: 12/14/2020] [Indexed: 01/02/2023]
Abstract
AIMS Huntington disease (HD) is a fatal neurodegenerative disorder with no disease-modifying treatments approved so far. Ongoing clinical trials are attempting to reduce huntingtin (HTT) expression in the central nervous system (CNS) using different strategies. Yet, the distribution and timing of HTT-lowering therapies required for a beneficial clinical effect is less clear. Here, we investigated whether HD-related behaviours could be prevented by inactivating mutant HTT at different disease stages and to varying degrees in an experimental model. METHODS We generated mutant BACHD mice with either a widespread or circuit-specific inactivation of mutant HTT by using Cre recombinase (Cre) under the nestin promoter or the adenosine A2A receptor promoter respectively. We also simulated a clinical gene therapy scenario with allele-specific HTT targeting by injections of recombinant adeno-associated viral (rAAV) vectors expressing Cre into the striatum of adult BACHD mice. All mice were assessed using behavioural tests to investigate motor, metabolic and psychiatric outcome measures at 4-6 months of age. RESULTS While motor deficits, body weight changes, anxiety and depressive-like behaviours are present in BACHD mice, early widespread CNS inactivation during development significantly improves rotarod performance, body weight changes and depressive-like behaviour. However, conditional circuit-wide mutant HTT deletion from the indirect striatal pathway during development and focal striatal-specific deletion in adulthood failed to rescue any of the HD-related behaviours. CONCLUSIONS Our results indicate that widespread targeting and the timing of interventions aimed at reducing mutant HTT are important factors to consider when developing disease-modifying therapies for HD.
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Affiliation(s)
- Rachel Y. Cheong
- Translational Neuroendocrine Research UnitDepartment of Experimental Medical ScienceLund UniversityLundSweden
| | - Barbara Baldo
- Translational Neuroendocrine Research UnitDepartment of Experimental Medical ScienceLund UniversityLundSweden
- Present address:
Evotec SEHD Research and Translational SciencesHamburgGermany
| | - Muhammad U. Sajjad
- Translational Neuroendocrine Research UnitDepartment of Experimental Medical ScienceLund UniversityLundSweden
| | - Deniz Kirik
- Brain Repair and Imaging in Neural Systems UnitDepartment of Experimental Medical ScienceLund UniversityLundSweden
| | - Åsa Petersén
- Translational Neuroendocrine Research UnitDepartment of Experimental Medical ScienceLund UniversityLundSweden
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25
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Molecular conformations and dynamics of nucleotide repeats associated with neurodegenerative diseases: double helices and CAG hairpin loops. Comput Struct Biotechnol J 2021; 19:2819-2832. [PMID: 34093995 PMCID: PMC8138726 DOI: 10.1016/j.csbj.2021.04.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/13/2021] [Accepted: 04/16/2021] [Indexed: 01/05/2023] Open
Abstract
Pathogenic DNA secondary structures have been identified as a common and causative factor for expansion in trinucleotide, hexanucleotide, and other simple sequence repeats. These expansions underlie about fifty neurological and neuromuscular disorders known as “anticipation diseases”. Cell toxicity and death have been linked to the pathogenic conformations and functional changes of the RNA transcripts, of DNA itself and, when trinucleotides are present in exons, of the translated proteins. We review some of our results for the conformations and dynamics of pathogenic structures for both RNA and DNA, which include mismatched homoduplexes formed by trinucleotide repeats CAG and GAC; CCG and CGG; CTG(CUG) and GTC(GUC); the dynamics of DNA CAG hairpins; mismatched homoduplexes formed by hexanucleotide repeats (GGGGCC) and (GGCCCC); and G-quadruplexes formed by (GGGGCC) and (GGGCCT). We also discuss the dynamics of strand slippage in DNA hairpins formed by CAG repeats as observed with single-molecule Fluorescence Resonance Energy Transfer. This review focuses on the rich behavior exhibited by the mismatches associated with these simple sequence repeat noncanonical structures.
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26
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Elorza A, Márquez Y, Cabrera JR, Sánchez-Trincado JL, Santos-Galindo M, Hernández IH, Picó S, Díaz-Hernández JI, García-Escudero R, Irimia M, Lucas JJ. Huntington's disease-specific mis-splicing unveils key effector genes and altered splicing factors. Brain 2021; 144:2009-2023. [PMID: 33725094 PMCID: PMC8370404 DOI: 10.1093/brain/awab087] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 12/21/2020] [Accepted: 12/24/2020] [Indexed: 12/31/2022] Open
Abstract
Correction of mis-splicing events is a growing therapeutic approach for neurological diseases such as spinal muscular atrophy or neuronal ceroid lipofuscinosis 7, which are caused by splicing-affecting mutations. Mis-spliced effector genes that do not harbour mutations are also good candidate therapeutic targets in diseases with more complex aetiologies such as cancer, autism, muscular dystrophies or neurodegenerative diseases. Next-generation RNA sequencing (RNA-seq) has boosted investigation of global mis-splicing in diseased tissue to identify such key pathogenic mis-spliced genes. Nevertheless, while analysis of tumour or dystrophic muscle biopsies can be informative on early stage pathogenic mis-splicing, for neurodegenerative diseases, these analyses are intrinsically hampered by neuronal loss and neuroinflammation in post-mortem brains. To infer splicing alterations relevant to Huntington’s disease pathogenesis, here we performed intersect-RNA-seq analyses of human post-mortem striatal tissue and of an early symptomatic mouse model in which neuronal loss and gliosis are not yet present. Together with a human/mouse parallel motif scan analysis, this approach allowed us to identify the shared mis-splicing signature triggered by the Huntington’s disease-causing mutation in both species and to infer upstream deregulated splicing factors. Moreover, we identified a plethora of downstream neurodegeneration-linked mis-spliced effector genes that—together with the deregulated splicing factors—become new possible therapeutic targets. In summary, here we report pathogenic global mis-splicing in Huntington’s disease striatum captured by our new intersect-RNA-seq approach that can be readily applied to other neurodegenerative diseases for which bona fide animal models are available.
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Affiliation(s)
- Ainara Elorza
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
| | - Yamile Márquez
- Centre for Genomic Regulation (CRG), Barcelona Institute for Science and Technology, 08003 Barcelona, Spain
| | - Jorge R Cabrera
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
| | - José Luis Sánchez-Trincado
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
| | - María Santos-Galindo
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
| | - Ivó H Hernández
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain.,Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Sara Picó
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
| | - Juan I Díaz-Hernández
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
| | - Ramón García-Escudero
- Molecular Oncology Unit, CIEMAT, Madrid 28040, Spain.,Biomedical Research Institute i+12, Hospital 12 de Octubre, Madrid 28041, Spain.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Instituto de Salud Carlos III, Madrid 28029, Spain
| | - Manuel Irimia
- Centre for Genomic Regulation (CRG), Barcelona Institute for Science and Technology, 08003 Barcelona, Spain.,Universitat Pompeu Fabra, 08003, Barcelona, Spain.,ICREA, Barcelona, Spain
| | - José J Lucas
- Center for Molecular Biology 'Severo Ochoa' (CBMSO) CSIC/UAM, Madrid 28049, Spain.,Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain
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27
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Piasecka A, Sekrecki M, Szcześniak MW, Sobczak K. MEF2C shapes the microtranscriptome during differentiation of skeletal muscles. Sci Rep 2021; 11:3476. [PMID: 33568691 PMCID: PMC7875991 DOI: 10.1038/s41598-021-82706-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 01/20/2021] [Indexed: 01/04/2023] Open
Abstract
Myocyte enhancer factor 2C (MEF2C) is a transcription factor that regulates heart and skeletal muscle differentiation and growth. Several protein-encoding genes were identified as targets of this factor; however, little is known about its contribution to the microtranscriptome composition and dynamics in myogenic programs. In this report, we aimed to address this question. Deep sequencing of small RNAs of human muscle cells revealed a set of microRNAs (miRNAs), including several muscle-specific miRNAs, that are sensitive to MEF2C depletion. As expected, in cells with knockdown of MEF2C, we found mostly downregulated miRNAs; nevertheless, as much as one-third of altered miRNAs were upregulated. The majority of these changes are driven by transcription efficiency. Moreover, we found that MEF2C affects nontemplated 3′-end nucleotide addition of miRNAs, mainly oligouridylation. The rate of these modifications is associated with the level of TUT4 which mediates RNA 3′-uridylation. Finally, we found that a quarter of miRNAs which significantly changed upon differentiation of human skeletal myoblasts is inversely altered in MEF2C deficient cells. We concluded that MEF2C is an essential factor regulating both the quantity and quality of the microtranscriptome, leaving an imprint on the stability and perhaps specificity of many miRNAs during the differentiation of muscle cells.
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Affiliation(s)
- Agnieszka Piasecka
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznań, Poland
| | - Michał Sekrecki
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznań, Poland
| | - Michał Wojciech Szcześniak
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznań, Poland
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznań, Poland.
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28
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Haruehanroengra P, Vangaveti S, Ranganathan SV, Mao S, Su MD, Chen AA, Sheng J. Terpene Chain Length Affects the Base Pairing Discrimination of S-geranyl-2-thiouridine in RNA Duplex. iScience 2020; 23:101866. [PMID: 33319183 PMCID: PMC7726334 DOI: 10.1016/j.isci.2020.101866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/16/2020] [Accepted: 11/20/2020] [Indexed: 12/20/2022] Open
Abstract
Geranylation is a hydrophobic modification discovered in several bacteria tRNAs with the function of promoting codon bias during translation. However, why nature selects this C10-geranyl group remains a question. We conduct synthesis, UV-thermal denaturation, and molecular simulation studies in RNA duplexes and reveal possible reasons behind this natural selection. Among methyl-(C1), dimethylallyl-(C5), geranyl-(C10), and farnesyl-(C15) modified 2-thiouridines, only geranyl-group promotes U:G over U:A pair. Molecular simulation shows all the modified terpene groups point to the minor groove of RNA duplexes. The discrimination between U:G and U:A pairs derives from the difference in hydrogen bonding and interactions of the chain with the hydrophobic area in the minor groove. Geranyl group has perfect length to discriminate U:G and U:A pairs, whereas the others are either too long or too short to achieve the same behavior. This work indicates that geranyl group cannot be replaced by other terpene groups in promoting codon-specificity. Geranyl group on ges2U has perfect length to enhance binding to G over A in RNA Other ges2U analogues has no pairing preference between G or A MD shows the molecular dynamic behavior of different terpene chains in RNA duplex
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Affiliation(s)
- Phensinee Haruehanroengra
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA.,The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Sweta Vangaveti
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | | | - Song Mao
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA.,The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Max Daniel Su
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA.,The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Alan A Chen
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA.,The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jia Sheng
- Department of Chemistry, University at Albany, State University of New York, 1400 Washington Avenue, Albany, NY 12222, USA.,The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
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29
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van Cruchten RTP, Wansink DG. In Vitro Synthesis and RNA Structure Probing of CUG Triplet Repeat RNA. Methods Mol Biol 2020; 2056:187-202. [PMID: 31586349 DOI: 10.1007/978-1-4939-9784-8_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aberrant RNA structure plays a central role in the molecular mechanisms guided by repeat RNAs in diseases like myotonic dystrophy (DM), C9orf72-linked amyotrophic lateral sclerosis (ALS) and fragile X tremor/ataxia syndrome (FXTAS). Much knowledge remains to be gained about how these repeat-expanded transcripts are actually folded, especially regarding the properties specific to very long and interrupted repeats. RNA structure can be interrogated by chemical as well as enzymatic probes. These probes usually bind or cleave single-stranded nucleotides, which can subsequently be detected using reverse transcriptase primer extension. In this chapter, we describe methodology for in vitro synthesis and structure probing of expanded CUG repeat RNAs associated with DM type 1 and approaches for the associated data analysis.
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Affiliation(s)
- Remco T P van Cruchten
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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30
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An Overview of Alternative Splicing Defects Implicated in Myotonic Dystrophy Type I. Genes (Basel) 2020; 11:genes11091109. [PMID: 32971903 PMCID: PMC7564762 DOI: 10.3390/genes11091109] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 01/02/2023] Open
Abstract
Myotonic dystrophy type I (DM1) is the most common form of adult muscular dystrophy, caused by expansion of a CTG triplet repeat in the 3′ untranslated region (3′UTR) of the myotonic dystrophy protein kinase (DMPK) gene. The pathological CTG repeats result in protein trapping by expanded transcripts, a decreased DMPK translation and the disruption of the chromatin structure, affecting neighboring genes expression. The muscleblind-like (MBNL) and CUG-BP and ETR-3-like factors (CELF) are two families of tissue-specific regulators of developmentally programmed alternative splicing that act as antagonist regulators of several pre-mRNA targets, including troponin 2 (TNNT2), insulin receptor (INSR), chloride channel 1 (CLCN1) and MBNL2. Sequestration of MBNL proteins and up-regulation of CELF1 are key to DM1 pathology, inducing a spliceopathy that leads to a developmental remodelling of the transcriptome due to an adult-to-foetal splicing switch, which results in the loss of cell function and viability. Moreover, recent studies indicate that additional pathogenic mechanisms may also contribute to disease pathology, including a misregulation of cellular mRNA translation, localization and stability. This review focuses on the cause and effects of MBNL and CELF1 deregulation in DM1, describing the molecular mechanisms underlying alternative splicing misregulation for a deeper understanding of DM1 complexity. To contribute to this analysis, we have prepared a comprehensive list of transcript alterations involved in DM1 pathogenesis, as well as other deregulated mRNA processing pathways implications.
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31
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Johnson SL, Ranxhi B, Libohova K, Tsou WL, Todi SV. Ubiquitin-interacting motifs of ataxin-3 regulate its polyglutamine toxicity through Hsc70-4-dependent aggregation. eLife 2020; 9:60742. [PMID: 32955441 PMCID: PMC7505662 DOI: 10.7554/elife.60742] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/30/2020] [Indexed: 12/17/2022] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) belongs to the family of polyglutamine neurodegenerations. Each disorder stems from the abnormal lengthening of a glutamine repeat in a different protein. Although caused by a similar mutation, polyglutamine disorders are distinct, implicating non-polyglutamine regions of disease proteins as regulators of pathogenesis. SCA3 is caused by polyglutamine expansion in ataxin-3. To determine the role of ataxin-3’s non-polyglutamine domains in disease, we utilized a new, allelic series of Drosophila melanogaster. We found that ataxin-3 pathogenicity is saliently controlled by polyglutamine-adjacent ubiquitin-interacting motifs (UIMs) that enhance aggregation and toxicity. UIMs function by interacting with the heat shock protein, Hsc70-4, whose reduction diminishes ataxin-3 toxicity in a UIM-dependent manner. Hsc70-4 also enhances pathogenicity of other polyglutamine proteins. Our studies provide a unique insight into the impact of ataxin-3 domains in SCA3, identify Hsc70-4 as a SCA3 enhancer, and indicate pleiotropic effects from HSP70 chaperones, which are generally thought to suppress polyglutamine degeneration.
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Affiliation(s)
- Sean L Johnson
- Department of Pharmacology, Wayne State University, Detroit, United States
| | - Bedri Ranxhi
- Department of Pharmacology, Wayne State University, Detroit, United States
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University, Detroit, United States
| | - Wei-Ling Tsou
- Department of Pharmacology, Wayne State University, Detroit, United States
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University, Detroit, United States.,Department of Neurology, Wayne State University, Detroit, United States
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32
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Binas O, Bessi I, Schwalbe H. Structure Validation of G-Rich RNAs in Noncoding Regions of the Human Genome. Chembiochem 2020; 21:1656-1663. [PMID: 31943589 PMCID: PMC7318348 DOI: 10.1002/cbic.201900696] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Indexed: 12/22/2022]
Abstract
We present the rapid biophysical characterization of six previously reported putative G-quadruplex-forming RNAs from the 5'-untranslated region (5'-UTR) of silvestrol-sensitive transcripts for investigation of their secondary structures. By NMR and CD spectroscopic analysis, we found that only a single sequence-[AGG]2 [CGG]2 C-folds into a single well-defined G-quadruplex structure. Sequences with longer poly-G strands form unspecific aggregates, whereas CGG-repeat-containing sequences exhibit a temperature-dependent equilibrium between a hairpin and a G-quadruplex structure. The applied experimental strategy is fast and provides robust readout for G-quadruplex-forming capacities of RNA oligomers.
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Affiliation(s)
- Oliver Binas
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue Strasse 760438FrankfurtGermany
| | - Irene Bessi
- Institute for Organic and Biomolecular ChemistryJulius Maximilians University WürzburgAm Hubland97074WürzburgGermany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue Strasse 760438FrankfurtGermany
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33
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Abstract
Trinucleotide repeats are a peculiar class of microsatellites involved in many neurological as well as developmental disorders. Their propensity to generate very large expansions over time is supposedly due to their capacity to form specific secondary structures, such as imperfect hairpins, triple helices, or G-quadruplexes. These unusual structures were proposed to trigger expansions in vivo. Here, I review known technical issues linked to these structures, such as slippage during polymerase chain reaction and aberrant migration of long trinucleotide repeats during agarose gel electrophoresis. Our current understanding of interactions between trinucleotide repeat secondary structures and the mismatch-repair machinery is also quickly reviewed, and critical questions relevant to these interactions are addressed.
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Affiliation(s)
- Guy-Franck Richard
- Department Genomes & Genetics, Institut Pasteur, CNRS UMR3525, Paris, France.
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34
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Mukherjee S, Błaszczyk L, Rypniewski W, Falschlunger C, Micura R, Murata A, Dohno C, Nakatani K, Kiliszek A. Structural insights into synthetic ligands targeting A-A pairs in disease-related CAG RNA repeats. Nucleic Acids Res 2019; 47:10906-10913. [PMID: 31566242 PMCID: PMC6847237 DOI: 10.1093/nar/gkz832] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/07/2019] [Accepted: 09/26/2019] [Indexed: 12/17/2022] Open
Abstract
The trinucleotide repeat expansion disorders (TREDs) constitute of a group of >40 hereditary neurodegenerative human diseases associated with abnormal expansion of repeated sequences, such as CAG repeats. The pathogenic factor is a transcribed RNA or protein whose function in the cell is compromised. The disorders are progressive and incurable. Consequently, many ongoing studies are oriented at developing therapies. We have analyzed crystal structures of RNA containing CAG repeats in complex with synthetic cyclic mismatch-binding ligands (CMBLs). The models show well-defined interactions between the molecules in which the CMBLs mimic nucleobases as they form pseudo-canonical base pairs with adenosine residues and engage in extensive stacking interactions with neighboring nucleotides. The binding of ligands is associated with major structural changes of the CAG repeats, which is consistent with results of biochemical studies. The results constitute an early characterization of the first lead compounds in the search for therapy against TREDs. The crystallographic data indicate how the compounds could be further refined in future biomedical studies.
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Affiliation(s)
- Sanjukta Mukherjee
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University 8-1 Mihogaoka, Ibaraki 567-0047, Japan
| | - Leszek Błaszczyk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wojciech Rypniewski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Christoph Falschlunger
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria
| | - Asako Murata
- 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
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University 8-1 Mihogaoka, Ibaraki 567-0047, Japan
| | - Agnieszka Kiliszek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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35
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Murata A, Nakamori M, Nakatani K. Modulating RNA secondary and tertiary structures by mismatch binding ligands. Methods 2019; 167:78-91. [DOI: 10.1016/j.ymeth.2019.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 05/05/2019] [Accepted: 05/07/2019] [Indexed: 12/21/2022] Open
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36
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Verma AK, Khan E, Mishra SK, Jain N, Kumar A. Piperine Modulates Protein Mediated Toxicity in Fragile X-Associated Tremor/Ataxia Syndrome through Interacting Expanded CGG Repeat (r(CGG) exp) RNA. ACS Chem Neurosci 2019; 10:3778-3788. [PMID: 31264835 DOI: 10.1021/acschemneuro.9b00282] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
An expansion of CGG tandem repeats in the 5' untranslated region (5'-UTR) of fragile X mental retardation 1 (FMR1) gene causes fragile X-associated tremor/ataxia syndrome (FXTAS). The transcripts of these expanded repeats r(CGG)exp either form RNA foci or undergo the repeat-associated non-ATG (RAN) translation that produces toxic homopolymeric proteins in neuronal cells. The discovery of small molecule modulators that possess a strong binding affinity and high selectivity to these toxic expanded repeats RNA could be a promising therapeutic approach to cure the expanded repeat-associated neurological diseases. Therefore, here we sought to test the therapeutic potential of a natural alkaloid, piperine, by assessing its ability to bind and neutralize the toxicity of r(CGG)exp RNA motif. To accomplish this first, we have determined the affinity of piperine to r(CGG)exp RNA using fluorescence-based binding assay and isothermal titration calorimetry assay. These assays showed that piperine forms a thermodynamically favorable interaction with r(CGG)exp RNA with high selectivity to the G-rich RNA motif. Interaction of piperine with r(CGG)exp motif was further validated using several biophysical techniques such as CD, CD melting, NMR spectroscopy, and gel retardation assay. Moreover, piperine was also found to be effective for improving the r(CGG)exp associated splicing defects and RAN translation in a FXTAS cell model system. Our results effectively provided the evidence that piperine strongly interacts with r(CGG)exp RNA and could be used as a suitable candidate for therapeutic development against FXTAS.
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Affiliation(s)
- Arun Kumar Verma
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Eshan Khan
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Subodh Kumar Mishra
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Neha Jain
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Amit Kumar
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
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Khan E, Biswas S, Mishra SK, Mishra R, Samanta S, Mishra A, Tawani A, Kumar A. Rationally designed small molecules targeting toxic CAG repeat RNA that causes Huntington's disease (HD) and spinocerebellar ataxia (SCAs). Biochimie 2019; 163:21-32. [DOI: 10.1016/j.biochi.2019.05.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 05/01/2019] [Indexed: 12/29/2022]
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Hale MA, Johnson NE, Berglund JA. Repeat-associated RNA structure and aberrant splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194405. [PMID: 31323433 DOI: 10.1016/j.bbagrm.2019.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Over 30 hereditary disorders attributed to the expansion of microsatellite repeats have been identified. Despite variant nucleotide content, number of consecutive repeats, and different locations in the genome, many of these diseases have pathogenic RNA gain-of-function mechanisms. The repeat-containing RNAs can form structures in vitro predicted to contribute to the disease through assembly of intracellular RNA aggregates termed foci. The expanded repeat RNAs within these foci sequester RNA binding proteins (RBPs) with important roles in the regulation of RNA metabolism, most notably alternative splicing (AS). These deleterious interactions lead to downstream alterations in transcriptome-wide AS directly linked with disease symptoms. This review summarizes existing knowledge about the association between the repeat RNA structures and RBPs as well as the resulting aberrant AS patterns, specifically in the context of myotonic dystrophy. The connection between toxic, structured RNAs and dysregulation of AS in other repeat expansion diseases is also discussed. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Melissa A Hale
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Nicholas E Johnson
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - J Andrew Berglund
- The RNA Institute, Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
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Johnson SL, Blount JR, Libohova K, Ranxhi B, Paulson HL, Tsou WL, Todi SV. Differential toxicity of ataxin-3 isoforms in Drosophila models of Spinocerebellar Ataxia Type 3. Neurobiol Dis 2019; 132:104535. [PMID: 31310802 DOI: 10.1016/j.nbd.2019.104535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/05/2019] [Accepted: 07/12/2019] [Indexed: 12/28/2022] Open
Abstract
The most commonly inherited dominant ataxia, Spinocerebellar Ataxia Type 3 (SCA3), is caused by a CAG repeat expansion that encodes an abnormally long polyglutamine (polyQ) repeat in the disease protein ataxin-3, a deubiquitinase. Two major full-length isoforms of ataxin-3 exist, both of which contain the same N-terminal portion and polyQ repeat, but differ in their C-termini; one (denoted here as isoform 1) contains a motif that binds ataxin-3's substrate, ubiquitin, whereas the other (denoted here as isoform 2) has a hydrophobic tail. Most SCA3 studies have focused on isoform 1, the predominant version in mammalian brain, yet both isoforms are present in brain and a better understanding of their relative pathogenicity in vivo is needed. We took advantage of the fruit fly, Drosophila melanogaster to model SCA3 and to examine the toxicity of each ataxin-3 isoform. Our assays reveal isoform 1 to be markedly more toxic than isoform 2 in all fly tissues. Reduced toxicity from isoform 2 is due to much lower protein levels as a result of its expedited degradation. Additional studies indicate that isoform 1 is more aggregation-prone than isoform 2 and that the C-terminus of isoform 2 is critical for its enhanced proteasomal degradation. According to our results, although both full-length, pathogenic ataxin-3 isoforms are toxic, isoform 1 is likely the primary contributor to SCA3 due to its presence at higher levels. Isoform 2, as a result of rapid degradation that is dictated by its tail, is unlikely to be a key player in this disease. Our findings provide new insight into the biology of this ataxia and the cellular processing of the underlying disease protein.
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Affiliation(s)
- Sean L Johnson
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Jessica R Blount
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Bedri Ranxhi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Wei-Ling Tsou
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI, USA; Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA.
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Van Treeck B, Parker R. Emerging Roles for Intermolecular RNA-RNA Interactions in RNP Assemblies. Cell 2019; 174:791-802. [PMID: 30096311 DOI: 10.1016/j.cell.2018.07.023] [Citation(s) in RCA: 255] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/05/2018] [Accepted: 07/20/2018] [Indexed: 12/22/2022]
Abstract
Eukaryotic cells contain large assemblies of RNA and protein, referred to as ribonucleoprotein (RNP) granules, which include cytoplasmic P-bodies, stress granules, and neuronal and germinal granules, as well as nuclear paraspeckles, Cajal bodies, and RNA foci formed from repeat expansion RNAs. Recent evidence argues that intermolecular RNA-RNA interactions play a role in forming and determining the composition of certain RNP granules. We hypothesize that intermolecular RNA-RNA interactions are favored in cells yet are limited by RNA-binding proteins, helicases, and ribosomes, thereby allowing normal RNA function. An over-abundance of intermolecular RNA-RNA interactions may be toxic since perturbations that increase RNA-RNA interactions such as long repeat expansion RNAs, arginine-containing dipeptide repeat polypeptides, and sequestration or loss of abundant RNA-binding proteins can contribute to degenerative diseases.
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Affiliation(s)
- Briana Van Treeck
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309, USA.
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41
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Repeat-Associated Non-ATG Translation in Neurological Diseases. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a033019. [PMID: 29891563 DOI: 10.1101/cshperspect.a033019] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
More than 40 different neurological diseases are caused by microsatellite repeat expansions that locate within translated or untranslated gene regions, including 5' and 3' untranslated regions (UTRs), introns, and protein-coding regions. Expansion mutations are transcribed bidirectionally and have been shown to give rise to proteins, which are synthesized from three reading frames in the absence of an AUG initiation codon through a novel process called repeat-associated non-ATG (RAN) translation. RAN proteins, which were first described in spinocerebellar ataxia type 8 (SCA8) and myotonic dystrophy type 1 (DM1), have now been reported in a growing list of microsatellite expansion diseases. This article reviews what is currently known about RAN proteins in microsatellite expansion diseases and experiments that provide clues on how RAN translation is regulated.
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Li J, Nakamori M, Matsumoto J, Murata A, Dohno C, Kiliszek A, Taylor K, Sobczak K, Nakatani K. A Dimeric 2,9‐Diamino‐1,10‐phenanthroline Derivative Improves Alternative Splicing in Myotonic Dystrophy Type 1 Cell and Mouse Models. Chemistry 2018; 24:18115-18122. [DOI: 10.1002/chem.201804368] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/05/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Jinxing Li
- Department of Regulatory Bioorganic ChemistryThe Institute of Scientific and Industrial ResearchOsaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Masayuki Nakamori
- Department of NeurologyGraduate School of MedicineOsaka University 2-2 Yamadaoka Suita 565-0871 Japan
| | - Jun Matsumoto
- Department of Regulatory Bioorganic ChemistryThe Institute of Scientific and Industrial ResearchOsaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Asako Murata
- Department of Regulatory Bioorganic ChemistryThe Institute of Scientific and Industrial ResearchOsaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Chikara Dohno
- Department of Regulatory Bioorganic ChemistryThe Institute of Scientific and Industrial ResearchOsaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
| | - Agnieszka Kiliszek
- Department of Structure and Function of BiomoleculesThe Institute of Bioorganic ChemistryPolish Academy of Sciences Z. Noskowskiego 12/14 61-704 Poznan Poland
| | - Katarzyna Taylor
- Department of Gene ExpressionLaboratory of Gene TherapyInstitute of Molecular Biology and BiotechnologyAdam Mickiewicz University Umultowska 89 61-614 Poznań Poland
| | - Krzysztof Sobczak
- Department of Gene ExpressionLaboratory of Gene TherapyInstitute of Molecular Biology and BiotechnologyAdam Mickiewicz University Umultowska 89 61-614 Poznań Poland
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic ChemistryThe Institute of Scientific and Industrial ResearchOsaka University 8-1 Mihogaoka Ibaraki 567-0047 Japan
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Activation of the interferon type I response rather than autophagy contributes to myogenesis inhibition in congenital DM1 myoblasts. Cell Death Dis 2018; 9:1071. [PMID: 30341284 PMCID: PMC6195593 DOI: 10.1038/s41419-018-1080-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 08/21/2018] [Accepted: 08/22/2018] [Indexed: 12/16/2022]
Abstract
Congenital myotonic dystrophy type 1 (CDM1) is characterized by severe symptoms that affect patients from birth, with 40% mortality in the neonatal period and impaired skeletal muscle development. In this paper, we examined the relationship between autophagy and abnormal myogenic differentiation of CDM1 myoblasts. We investigated these pathological features at both ultrastructural and molecular levels, utilizing two CDM1 foetal myoblasts, CDM13 and CDM15, with 1800 and 3200 repeats, respectively. The congenital nature of these CDM1 myoblasts was confirmed by the high methylation level at the DMPK locus. Our results indicated that abnormal autophagy was independent of myogenic differentiation, as CDM13 myoblasts differentiated as well as control myoblasts but underwent autophagy like CDM15, displaying impaired differentiation. miRNA expression profiles revealed that CDM15 myoblasts failed to upregulate the complex network of myo-miRNAs under MYOD and MEF2A control, while this network was upregulated in CDM13 myoblasts. Interestingly, the abnormal differentiation of CDM15 myoblasts was associated with cellular stress accompanied by the induction of the interferon type 1 pathway (innate immune response). Indeed, inhibition of the interferon (IFN) type I pathway restores myogenic differentiation of CDM15 myoblasts, suggesting that the inappropriate activation of the innate immune response might contribute to impaired myogenic differentiation and severe muscle symptoms observed in some CDM1 patients. These findings open up the possibility of new therapeutic approaches to treat CDM1.
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Glineburg MR, Todd PK, Charlet-Berguerand N, Sellier C. Repeat-associated non-AUG (RAN) translation and other molecular mechanisms in Fragile X Tremor Ataxia Syndrome. Brain Res 2018; 1693:43-54. [PMID: 29453961 PMCID: PMC6010627 DOI: 10.1016/j.brainres.2018.02.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/31/2018] [Accepted: 02/02/2018] [Indexed: 11/11/2022]
Abstract
Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset inherited neurodegenerative disorder characterized by progressive intention tremor, gait ataxia and dementia associated with mild brain atrophy. The cause of FXTAS is a premutation expansion, of 55 to 200 CGG repeats localized within the 5'UTR of FMR1. These repeats are transcribed in the sense and antisense directions into mutants RNAs, which have increased expression in FXTAS. Furthermore, CGG sense and CCG antisense expanded repeats are translated into novel proteins despite their localization in putatively non-coding regions of the transcript. Here we focus on two proposed disease mechanisms for FXTAS: 1) RNA gain-of-function, whereby the mutant RNAs bind specific proteins and preclude their normal functions, and 2) repeat-associated non-AUG (RAN) translation, whereby translation through the CGG or CCG repeats leads to the production of toxic homopolypeptides, which in turn interfere with a variety of cellular functions. Here, we analyze the data generated to date on both of these potential molecular mechanisms and lay out a path forward for determining which factors drive FXTAS pathogenicity.
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Affiliation(s)
| | - Peter K Todd
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Veteran's Affairs Medical Center, Ann Arbor, MI 48105, USA
| | - Nicolas Charlet-Berguerand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France
| | - Chantal Sellier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, 67400 Illkirch, France.
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45
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Moon SL, Sonenberg N, Parker R. Neuronal Regulation of eIF2α Function in Health and Neurological Disorders. Trends Mol Med 2018; 24:575-589. [PMID: 29716790 DOI: 10.1016/j.molmed.2018.04.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
Abstract
A key site of translation control is the phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α), which reduces the rate of GDP to GTP exchange by eIF2B, leading to altered translation. The extent of eIF2α phosphorylation within neurons can alter synaptic plasticity. Phosphorylation of eIF2α is triggered by four stress-responsive kinases, and as such eIF2α is often phosphorylated during neurological perturbations or disease. Moreover, in some cases decreasing eIF2α phosphorylation mitigates neurodegeneration, suggesting that this could be a therapeutic target. Mutations in the γ subunit of eIF2, the guanine exchange factor eIF2B, an eIF2α phosphatase, or in two eIF2α kinases can cause disease in humans, demonstrating the importance of proper regulation of eIF2α phosphorylation for health.
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Affiliation(s)
- Stephanie L Moon
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80303, USA.
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46
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Thadke SA, Perera JDR, Hridya VM, Bhatt K, Shaikh AY, Hsieh WC, Chen M, Gayathri C, Gil RR, Rule GS, Mukherjee A, Thornton CA, Ly DH. Design of Bivalent Nucleic Acid Ligands for Recognition of RNA-Repeated Expansion Associated with Huntington's Disease. Biochemistry 2018; 57:2094-2108. [PMID: 29562132 PMCID: PMC6091552 DOI: 10.1021/acs.biochem.8b00062] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We report the development of a new class of nucleic acid ligands that is comprised of Janus bases and the MPγPNA backbone and is capable of binding rCAG repeats in a sequence-specific and selective manner via, inference, bivalent H-bonding interactions. Individually, the interactions between ligands and RNA are weak and transient. However, upon the installation of a C-terminal thioester and an N-terminal cystine and the reduction of disulfide bond, they undergo template-directed native chemical ligation to form concatenated oligomeric products that bind tightly to the RNA template. In the absence of an RNA target, they self-deactivate by undergoing an intramolecular reaction to form cyclic products, rendering them inactive for further binding. The work has implications for the design of ultrashort nucleic acid ligands for targeting rCAG-repeat expansion associated with Huntington's disease and a number of other related neuromuscular and neurodegenerative disorders.
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Affiliation(s)
- Shivaji A. Thadke
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - J. Dinithi R. Perera
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - V. M. Hridya
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra 411008, India
| | - Kirti Bhatt
- Department of Neurology, Box 645, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Ashif Y. Shaikh
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Wei-Che Hsieh
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Mengshen Chen
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Chakicherla Gayathri
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Roberto R. Gil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Gordon S. Rule
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Arnab Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Maharashtra 411008, India
| | - Charles A. Thornton
- Department of Neurology, Box 645, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York 14642, United States
| | - Danith H. Ly
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Institute for Biomolecular Design and Discovery (IBD), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Center for Nucleic Acids Science and Technology (CNAST), Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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47
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Park Y, Kim KT, Kim BH. G-Quadruplex formation using fluorescent oligonucleotides as a detection method for discriminating AGG trinucleotide repeats. Chem Commun (Camb) 2018; 52:12757-12760. [PMID: 27722273 DOI: 10.1039/c6cc06566j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We have developed a simple and sensitive system for detecting AGG trinucleotide repeats through the formation of intermolecular G-quadruplexes using a fluorescent oligonucleotide. The fluorescence signal increased rapidly and dramatically by 44.7-fold with respect to the low background signal in the presence of RNA agg repeats and by 35.0-fold in the presence of DNA AGG repeats.
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Affiliation(s)
- Yoojin Park
- Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTEH), Pohang 37673, Republic of Korea.
| | - Ki Tae Kim
- Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTEH), Pohang 37673, Republic of Korea.
| | - Byeang Hyean Kim
- Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTEH), Pohang 37673, Republic of Korea.
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48
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Kapur M, Monaghan CE, Ackerman SL. Regulation of mRNA Translation in Neurons-A Matter of Life and Death. Neuron 2017; 96:616-637. [PMID: 29096076 DOI: 10.1016/j.neuron.2017.09.057] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/28/2017] [Indexed: 12/14/2022]
Abstract
Dynamic regulation of mRNA translation initiation and elongation is essential for the survival and function of neural cells. Global reductions in translation initiation resulting from mutations in the translational machinery or inappropriate activation of the integrated stress response may contribute to pathogenesis in a subset of neurodegenerative disorders. Aberrant proteins generated by non-canonical translation initiation may be a factor in the neuron death observed in the nucleotide repeat expansion diseases. Dysfunction of central components of the elongation machinery, such as the tRNAs and their associated enzymes, can cause translational infidelity and ribosome stalling, resulting in neurodegeneration. Taken together, dysregulation of mRNA translation is emerging as a unifying mechanism underlying the pathogenesis of many neurodegenerative disorders.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caitlin E Monaghan
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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49
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Chang T, Li W, Ding Z, Cheng S, Liang K, Liu X, Bing T, Shangguan D. Detection of G-Quadruplex Structures Formed by G-Rich Sequences from Rice Genome and Transcriptome Using Combined Probes. Anal Chem 2017; 89:8162-8169. [DOI: 10.1021/acs.analchem.7b01992] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Tianjun Chang
- Department
of Biology, Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, People’s Republic of China
| | - Weiguo Li
- Department
of Biology, Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, People’s Republic of China
| | - Zhan Ding
- Department
of Biology, Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, People’s Republic of China
| | - Shaofei Cheng
- Department
of Biology, Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, People’s Republic of China
| | - Kun Liang
- Department
of Biology, Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, People’s Republic of China
| | - Xiangjun Liu
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, CAS Research/Education Center for
Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, People’s Republic of China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Tao Bing
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, CAS Research/Education Center for
Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, People’s Republic of China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Dihua Shangguan
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Analytical
Chemistry for Living Biosystems, CAS Research/Education Center for
Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, People’s Republic of China
- University of the Chinese Academy of Sciences, Beijing 100049, China
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50
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Associating transcription factors and conserved RNA structures with gene regulation in the human brain. Sci Rep 2017; 7:5776. [PMID: 28720872 PMCID: PMC5516038 DOI: 10.1038/s41598-017-06200-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 06/20/2017] [Indexed: 02/06/2023] Open
Abstract
Anatomical subdivisions of the human brain can be associated with different neuronal functions. This functional diversification is reflected by differences in gene expression. By analyzing post-mortem gene expression data from the Allen Brain Atlas, we investigated the impact of transcription factors (TF) and RNA secondary structures on the regulation of gene expression in the human brain. First, we modeled the expression of a gene as a linear combination of the expression of TFs. We devised an approach to select robust TF-gene interactions and to determine localized contributions to gene expression of TFs. Among the TFs with the most localized contributions, we identified EZH2 in the cerebellum, NR3C1 in the cerebral cortex and SRF in the basal forebrain. Our results suggest that EZH2 is involved in regulating ZIC2 and SHANK1 which have been linked to neurological diseases such as autism spectrum disorder. Second, we associated enriched regulatory elements inside differentially expressed mRNAs with RNA secondary structure motifs. We found a group of purine-uracil repeat RNA secondary structure motifs plus other motifs in neuron related genes such as ACSL4 and ERLIN2.
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