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Chakraborty A, Sreenivasmurthy SG, Miller W, Huai W, Biswas T, Mandal SM, Boscá L, Krishnan B, Ghosh G, Hazra T. Fructose-2,6-bisphosphate restores DNA repair activity of PNKP and ameliorates neurodegenerative symptoms in Huntington's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.26.564220. [PMID: 37961108 PMCID: PMC10634858 DOI: 10.1101/2023.10.26.564220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3) are the two most prevalent polyglutamine (polyQ) neurodegenerative diseases, caused by CAG (encoding glutamine) repeat expansion in the coding region of the huntingtin (HTT) and ataxin-3 (ATXN3) proteins, respectively. We have earlier reported that the activity, but not the protein level, of an essential DNA repair enzyme, polynucleotide kinase 3'-phosphatase (PNKP), is severely abrogated in both HD and SCA3 resulting in accumulation of double-strand breaks in patients' brain genome. While investigating the mechanistic basis for the loss of PNKP activity and accumulation of DNA double-strand breaks leading to neuronal death, we observed that PNKP interacts with the nuclear isoform of 6-phosphofructo-2-kinase fructose-2,6-bisphosphatase 3 (PFKFB3). Depletion of PFKFB3 markedly abrogates PNKP activity without changing its protein level. Notably, the levels of both PFKFB3 and its product fructose-2,6 bisphosphate (F2,6BP), an allosteric modulator of glycolysis, are significantly lower in the nuclear extracts of post-mortem brain tissues of HD and SCA3 patients. Supplementation of F2,6BP restored PNKP activity in the nuclear extracts of patients' brain. Moreover, intracellular delivery of F2,6BP restored both the activity of PNKP and the integrity of transcribed genome in neuronal cells derived from striatum of HD mouse. Importantly, supplementing F2,6BP rescued the HD phenotype in Drosophila, suggesting F2,6BP to serve in vivo as a cofactor for the proper functionality of PNKP and thereby, of brain health. Our results thus provide a compelling rationale for exploring the therapeutic use of F2,6BP and structurally related compounds for treating polyQ diseases.
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Affiliation(s)
- Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | | | - Wyatt Miller
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Weihan Huai
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Tapan Biswas
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Santi Mohan Mandal
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Lisardo Boscá
- Instituto de Investigaciones Biomédicas Sols-Morreale (CSIC-UAM), and Centro de Investigación en Red en Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - Balaji Krishnan
- Department of Neurology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Gourisankar Ghosh
- Department of Chemistry and Biochemistry, University of California San Diego, LA Jolla, California 92093, USA
| | - Tapas Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, 77555, USA
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Lai Y, Diaz N, Armbrister R, Agoulnik I, Liu Y. DNA Base Damage Repair Crosstalks with Chromatin Structures to Contract Expanded GAA Repeats in Friedreich's Ataxia. Biomolecules 2024; 14:809. [PMID: 39062522 DOI: 10.3390/biom14070809] [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: 06/04/2024] [Revised: 06/29/2024] [Accepted: 07/03/2024] [Indexed: 07/28/2024] Open
Abstract
Trinucleotide repeat (TNR) expansion is the cause of over 40 neurodegenerative diseases, including Huntington's disease and Friedreich's ataxia (FRDA). There are no effective treatments for these diseases due to the poor understanding of molecular mechanisms underlying somatic TNR expansion and contraction in neural systems. We and others have found that DNA base excision repair (BER) actively modulates TNR instability, shedding light on the development of effective treatments for the diseases by contracting expanded repeats through DNA repair. In this study, temozolomide (TMZ) was employed as a model DNA base damaging agent to reveal the mechanisms of the BER pathway in modulating GAA repeat instability at the frataxin (FXN) gene in FRDA neural cells and transgenic mouse mice. We found that TMZ induced large GAA repeat contraction in FRDA mouse brain tissue, neurons, and FRDA iPSC-differentiated neural cells, increasing frataxin protein levels in FRDA mouse brain and neural cells. Surprisingly, we found that TMZ could also inhibit H3K9 methyltransferases, leading to open chromatin and increasing ssDNA breaks and recruitment of the key BER enzyme, pol β, on the repeats in FRDA neural cells. We further demonstrated that the H3K9 methyltransferase inhibitor BIX01294 also induced the contraction of the expanded repeats and increased frataxin protein in FRDA neural cells by opening the chromatin and increasing the endogenous ssDNA breaks and recruitment of pol β on the repeats. Our study provides new mechanistic insight illustrating that inhibition of H3K9 methylation can crosstalk with BER to induce GAA repeat contraction in FRDA. Our results will open a new avenue for developing novel gene therapy by targeting histone methylation and the BER pathway for repeat expansion diseases.
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Affiliation(s)
- Yanhao Lai
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
| | - Nicole Diaz
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
| | - Rhyisa Armbrister
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
| | - Irina Agoulnik
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
| | - Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, 11200 SW 8th Street, Miami, FL 33199, USA
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3
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P P, Riyaz A, Choudhury A, Choudhury PR, Pradhan N, Singh A, Nakul M, Dudeja C, Yadav A, Nath SK, Khanna V, Sharma T, Pradhan G, Takkar S, Rawal K. DNASCANNER v2: A Web-Based Tool to Analyze the Characteristic Properties of Nucleotide Sequences. J Comput Biol 2024; 31:651-669. [PMID: 38662479 DOI: 10.1089/cmb.2023.0227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024] Open
Abstract
Throughout the process of evolution, DNA undergoes the accumulation of distinct mutations, which can often result in highly organized patterns that serve various essential biological functions. These patterns encompass various genomic elements and provide valuable insights into the regulatory and functional aspects of DNA. The physicochemical, mechanical, thermodynamic, and structural properties of DNA sequences play a crucial role in the formation of specific patterns. These properties contribute to the three-dimensional structure of DNA and influence their interactions with proteins, regulatory elements, and other molecules. In this study, we introduce DNASCANNER v2, an advanced version of our previously published algorithm DNASCANNER for analyzing DNA properties. The current tool is built using the FLASK framework in Python language. Featuring a user-friendly interface tailored for nonspecialized researchers, it offers an extensive analysis of 158 DNA properties, including mono/di/trinucleotide frequencies, structural, physicochemical, thermodynamics, and mechanical properties of DNA sequences. The tool provides downloadable results and offers interactive plots for easy interpretation and comparison between different features. We also demonstrate the utility of DNASCANNER v2 in analyzing splice-site junctions, casposon insertion sequences, and transposon insertion sites (TIS) within the bacterial and human genomes, respectively. We also developed a deep learning module for the prediction of potential TIS in a given nucleotide sequence. In the future, we aim to optimize the performance of this prediction model through extensive training on larger data sets.
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Affiliation(s)
- Preeti P
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Azeen Riyaz
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Alakto Choudhury
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Priyanka Ray Choudhury
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Nischal Pradhan
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Abhishek Singh
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Mihir Nakul
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Chhavi Dudeja
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Abhijeet Yadav
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Swarsat Kaushik Nath
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Vrinda Khanna
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Trapti Sharma
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Gayatri Pradhan
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Simran Takkar
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Kamal Rawal
- Center for Computational Biology and Bioinformatics, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
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4
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Choi DE, Shin JW, Zeng S, Hong EP, Jang JH, Loupe JM, Wheeler VC, Stutzman HE, Kleinstiver B, Lee JM. Base editing strategies to convert CAG to CAA diminish the disease-causing mutation in Huntington's disease. eLife 2024; 12:RP89782. [PMID: 38869243 PMCID: PMC11175616 DOI: 10.7554/elife.89782] [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] [Indexed: 06/14/2024] Open
Abstract
An expanded CAG repeat in the huntingtin gene (HTT) causes Huntington's disease (HD). Since the length of uninterrupted CAG repeat, not polyglutamine, determines the age-at-onset in HD, base editing strategies to convert CAG to CAA are anticipated to delay onset by shortening the uninterrupted CAG repeat. Here, we developed base editing strategies to convert CAG in the repeat to CAA and determined their molecular outcomes and effects on relevant disease phenotypes. Base editing strategies employing combinations of cytosine base editors and guide RNAs (gRNAs) efficiently converted CAG to CAA at various sites in the CAG repeat without generating significant indels, off-target edits, or transcriptome alterations, demonstrating their feasibility and specificity. Candidate BE strategies converted CAG to CAA on both expanded and non-expanded CAG repeats without altering HTT mRNA and protein levels. In addition, somatic CAG repeat expansion, which is the major disease driver in HD, was significantly decreased in the liver by a candidate BE strategy treatment in HD knock-in mice carrying canonical CAG repeats. Notably, CAG repeat expansion was abolished entirely in HD knock-in mice carrying CAA-interrupted repeats, supporting the therapeutic potential of CAG-to-CAA conversion strategies in HD and potentially other repeat expansion disorders.
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Affiliation(s)
- Doo Eun Choi
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Jun Wan Shin
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Sophia Zeng
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
| | - Eun Pyo Hong
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
- Medical and Population Genetics Program, The Broad Institute of MIT and HarvardCambridgeUnited States
| | - Jae-Hyun Jang
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Jacob M Loupe
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Vanessa C Wheeler
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Hannah E Stutzman
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Pathology, Massachusetts General HospitalBostonUnited States
| | - Ben Kleinstiver
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Pathology, Massachusetts General HospitalBostonUnited States
- Department of Pathology, Harvard Medical SchoolBostonUnited States
| | - Jong-Min Lee
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
- Medical and Population Genetics Program, The Broad Institute of MIT and HarvardCambridgeUnited States
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5
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Kojak N, Kuno J, Fittipaldi KE, Khan A, Wenger D, Glasser M, Donnianni RA, Tang Y, Zhang J, Huling K, Ally R, Mujica AO, Turner T, Magardino G, Huang PY, Kerk SY, Droguett G, Prissette M, Rojas J, Gomez T, Gagliardi A, Hunt C, Rabinowitz JS, Gong G, Poueymirou W, Chiao E, Zambrowicz B, Siao CJ, Kajimura D. Somatic and intergenerational G4C2 hexanucleotide repeat instability in a human C9orf72 knock-in mouse model. Nucleic Acids Res 2024; 52:5732-5755. [PMID: 38597682 PMCID: PMC11162798 DOI: 10.1093/nar/gkae250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/11/2024] Open
Abstract
Expansion of a G4C2 repeat in the C9orf72 gene is associated with familial Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). To investigate the underlying mechanisms of repeat instability, which occurs both somatically and intergenerationally, we created a novel mouse model of familial ALS/FTD that harbors 96 copies of G4C2 repeats at a humanized C9orf72 locus. In mouse embryonic stem cells, we observed two modes of repeat expansion. First, we noted minor increases in repeat length per expansion event, which was dependent on a mismatch repair pathway protein Msh2. Second, we found major increases in repeat length per event when a DNA double- or single-strand break (DSB/SSB) was artificially introduced proximal to the repeats, and which was dependent on the homology-directed repair (HDR) pathway. In mice, the first mode primarily drove somatic repeat expansion. Major changes in repeat length, including expansion, were observed when SSB was introduced in one-cell embryos, or intergenerationally without DSB/SSB introduction if G4C2 repeats exceeded 400 copies, although spontaneous HDR-mediated expansion has yet to be identified. These findings provide a novel strategy to model repeat expansion in a non-human genome and offer insights into the mechanism behind C9orf72 G4C2 repeat instability.
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Affiliation(s)
- Nada Kojak
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Junko Kuno
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - David Wenger
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - Yajun Tang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Jade Zhang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Katie Huling
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Roxanne Ally
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | | | - Pei Yi Huang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Sze Yen Kerk
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | - Jose Rojas
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | | | | | | | - Guochun Gong
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Eric Chiao
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
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6
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Darlami O, Pun R, Ahn SH, Kim SH, Shin D. Macrocyclization strategy for improving candidate profiles in medicinal chemistry. Eur J Med Chem 2024; 272:116501. [PMID: 38754142 DOI: 10.1016/j.ejmech.2024.116501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/12/2024] [Accepted: 05/12/2024] [Indexed: 05/18/2024]
Abstract
Macrocycles are defined as cyclic compounds with 12 or more members. In medicinal chemistry, they are categorized based on their core chemistry into cyclic peptides and macrocycles. Macrocycles are advantageous because of their structural diversity and ability to achieve high affinity and selectivity towards challenging targets that are often not addressable by conventional small molecules. The potential of macrocyclization to optimize drug-like properties while maintaining adequate bioavailability and permeability has been emphasized as a key innovation in medicinal chemistry. This review provides a detailed case study of the application of macrocyclization over the past 5 years, starting from the initial analysis of acyclic active compounds to optimization of the resulting macrocycles for improved efficacy and drug-like properties. Additionally, it illustrates the strategic value of macrocyclization in contemporary drug discovery efforts.
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Affiliation(s)
- Om Darlami
- College of Pharmacy, Gachon University, Hambakmoe-ro 191, Yeunsu-gu, Incheon, 21935, Republic of Korea
| | - Rabin Pun
- College of Pharmacy, Gachon University, Hambakmoe-ro 191, Yeunsu-gu, Incheon, 21935, Republic of Korea
| | - Sung-Hoon Ahn
- College of Pharmacy, Kangwon National University, Gangwondaehak-gil 1, Chuncheon, Gangwon-do, 24341, Republic of Korea
| | - Seok-Ho Kim
- College of Pharmacy, Kangwon National University, Gangwondaehak-gil 1, Chuncheon, Gangwon-do, 24341, Republic of Korea.
| | - Dongyun Shin
- College of Pharmacy, Gachon University, Hambakmoe-ro 191, Yeunsu-gu, Incheon, 21935, Republic of Korea.
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7
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Gadgil RY, Rider SD, Shrestha R, Alhawach V, Hitch D, Leffak M. Microsatellite break-induced replication generates highly mutagenized extrachromosomal circular DNAs. NAR Cancer 2024; 6:zcae027. [PMID: 38854437 PMCID: PMC11161834 DOI: 10.1093/narcan/zcae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/17/2024] [Accepted: 05/24/2024] [Indexed: 06/11/2024] Open
Abstract
Extrachromosomal circular DNAs (eccDNAs) are produced from all regions of the eucaryotic genome. We used inverse PCR of non-B microsatellites capable of forming hairpin, triplex, quadruplex and AT-rich structures integrated at a common ectopic chromosomal site to show that these non-B DNAs generate highly mutagenized eccDNAs by replication-dependent mechanisms. Mutagenesis occurs within the non-B DNAs and extends several kilobases bidirectionally into flanking and nonallelic DNA. Each non-B DNA exhibits a different pattern of mutagenesis, while sister clones containing the same non-B DNA also display distinct patterns of recombination, microhomology-mediated template switching and base substitutions. Mutations include mismatches, short duplications, long nontemplated insertions, large deletions and template switches to sister chromatids and nonallelic chromosomes. Drug-induced replication stress or the depletion of DNA repair factors Rad51, the COPS2 signalosome subunit or POLη change the pattern of template switching and alter the eccDNA mutagenic profiles. We propose an asynchronous capture model based on break-induced replication from microsatellite-induced DNA double strand breaks to account for the generation and circularization of mutagenized eccDNAs and the appearance of genomic homologous recombination deficiency (HRD) scars. These results may help to explain the appearance of tumor eccDNAS and their roles in neoantigen production, oncogenesis and resistance to chemotherapy.
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Affiliation(s)
- Rujuta Yashodhan Gadgil
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - S Dean Rider
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Resha Shrestha
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Venicia Alhawach
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - David C Hitch
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Michael Leffak
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
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Su C, Chandradoss KR, Malachowski T, Boya R, Ryu HS, Brennand KJ, Phillips-Cremins JE. MASTR-seq: Multiplexed Analysis of Short Tandem Repeats with sequencing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.29.591790. [PMID: 38746155 PMCID: PMC11092654 DOI: 10.1101/2024.04.29.591790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
More than 60 human disorders have been linked to unstable expansion of short tandem repeat (STR) tracts. STR length and the extent of DNA methylation is linked to disease pathology and can be mosaic in a cell type-specific manner in several repeat expansion disorders. Mosaic phenomenon have been difficult to study to date due to technical bias intrinsic to repeat sequences and the need for multi-modal measurements at single-allele resolution. Nanopore long-read sequencing accurately measures STR length and DNA methylation in the same single molecule but is cost prohibitive for studies assessing a target locus across multiple experimental conditions or patient samples. Here, we describe MASTR-seq, M ultiplexed A nalysis of S hort T andem R epeats, for cost-effective, high-throughput, accurate, multi-modal measurements of DNA methylation and STR genotype at single-allele resolution. MASTR-seq couples long-read sequencing, Cas9-mediated target enrichment, and PCR-free multiplexed barcoding to achieve a >ten-fold increase in on-target read mapping for 8-12 pooled samples in a single MinION flow cell. We provide a detailed experimental protocol and computational tools and present evidence that MASTR-seq quantifies tract length and DNA methylation status for CGG and CAG STR loci in normal-length and mutation-length human cell lines. The MASTR-seq protocol takes approximately eight days for experiments and one additional day for data processing and analyses. Key points We provide a protocol for MASTR-seq: M ultiplexed A nalysis of S hort T andem R epeats using Cas9-mediated target enrichment and PCR-free, multiplexed nanopore sequencing. MASTR-seq achieves a >10-fold increase in on-target read proportion for highly repetitive, technically inaccessible regions of the genome relevant for human health and disease.MASTR-seq allows for high-throughput, efficient, accurate, and cost-effective measurement of STR length and DNA methylation in the same single allele for up to 8-12 samples in parallel in one Nanopore MinION flow cell.
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Lee KH, Kim J, Kim JH. 3D epigenomics and 3D epigenopathies. BMB Rep 2024; 57:216-231. [PMID: 38627948 PMCID: PMC11139681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 01/15/2024] [Accepted: 03/18/2024] [Indexed: 05/25/2024] Open
Abstract
Mammalian genomes are intricately compacted to form sophisticated 3-dimensional structures within the tiny nucleus, so called 3D genome folding. Despite their shapes reminiscent of an entangled yarn, the rapid development of molecular and next-generation sequencing technologies (NGS) has revealed that mammalian genomes are highly organized in a hierarchical order that delicately affects transcription activities. An increasing amount of evidence suggests that 3D genome folding is implicated in diseases, giving us a clue on how to identify novel therapeutic approaches. In this review, we will study what 3D genome folding means in epigenetics, what types of 3D genome structures there are, how they are formed, and how the technologies have developed to explore them. We will also discuss the pathological implications of 3D genome folding. Finally, we will discuss how to leverage 3D genome folding and engineering for future studies. [BMB Reports 2024; 57(5): 216-231].
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Affiliation(s)
- Kyung-Hwan Lee
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Jungyu Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
| | - Ji Hun Kim
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea
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Waldo JJ, Halmai JANM, Fink KD. Epigenetic editing for autosomal dominant neurological disorders. Front Genome Ed 2024; 6:1304110. [PMID: 38510848 PMCID: PMC10950933 DOI: 10.3389/fgeed.2024.1304110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 02/23/2024] [Indexed: 03/22/2024] Open
Abstract
Epigenetics refers to the molecules and mechanisms that modify gene expression states without changing the nucleotide context. These modifications are what encode the cell state during differentiation or epigenetic memory in mitosis. Epigenetic modifications can alter gene expression by changing the chromatin architecture by altering the affinity for DNA to wrap around histone octamers, forming nucleosomes. The higher affinity the DNA has for the histones, the tighter it will wrap and therefore induce a heterochromatin state, silencing gene expression. Several groups have shown the ability to harness the cell's natural epigenetic modification pathways to engineer proteins that can induce changes in epigenetics and consequently regulate gene expression. Therefore, epigenetic modification can be used to target and treat disorders through the modification of endogenous gene expression. The use of epigenetic modifications may prove an effective path towards regulating gene expression to potentially correct or cure genetic disorders.
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Affiliation(s)
| | | | - Kyle D. Fink
- Neurology Department, Stem Cell Program and Gene Therapy Center, MIND Institute, UC Davis Health System, Sacramento, CA, United States
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11
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Lu J, Toro C, Adams DR, Moreno CAM, Lee WP, Leung YY, Harms MB, Vardarajan B, Heinzen EL. LUSTR: a new customizable tool for calling genome-wide germline and somatic short tandem repeat variants. BMC Genomics 2024; 25:115. [PMID: 38279154 PMCID: PMC10811831 DOI: 10.1186/s12864-023-09935-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 12/21/2023] [Indexed: 01/28/2024] Open
Abstract
BACKGROUND Short tandem repeats (STRs) are widely distributed across the human genome and are associated with numerous neurological disorders. However, the extent that STRs contribute to disease is likely under-estimated because of the challenges calling these variants in short read next generation sequencing data. Several computational tools have been developed for STR variant calling, but none fully address all of the complexities associated with this variant class. RESULTS Here we introduce LUSTR which is designed to address some of the challenges associated with STR variant calling by enabling more flexibility in defining STR loci, allowing for customizable modules to tailor analyses, and expanding the capability to call somatic and multiallelic STR variants. LUSTR is a user-friendly and easily customizable tool for targeted or unbiased genome-wide STR variant screening that can use either predefined or novel genome builds. Using both simulated and real data sets, we demonstrated that LUSTR accurately infers germline and somatic STR expansions in individuals with and without diseases. CONCLUSIONS LUSTR offers a powerful and user-friendly approach that allows for the identification of STR variants and can facilitate more comprehensive studies evaluating the role of pathogenic STR variants across human diseases.
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Affiliation(s)
- Jinfeng Lu
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- The Taub Institute for Research On Alzheimer's Disease and the Aging Brain, Gertrude H. Sergievsky Center, Department of Neurology, College of Physicians and Surgeons, Columbia University, The New York Presbyterian Hospital, New York, NY, 10032, USA.
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health, Bethesda, MD, 20892, USA
| | - David R Adams
- NIH Undiagnosed Diseases Program, National Human Genome Research Institute (NHGRI), National Institutes of Health, Bethesda, MD, 20892, USA
| | | | - Wan-Ping Lee
- Penn Neurodegeneration Genomics Center, Department of Pathology and Laboratory MedicinePerelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yuk Yee Leung
- Penn Neurodegeneration Genomics Center, Department of Pathology and Laboratory MedicinePerelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Mathew B Harms
- Department of Neurology, Division of Neuromuscular Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Badri Vardarajan
- The Taub Institute for Research On Alzheimer's Disease and the Aging Brain, Gertrude H. Sergievsky Center, Department of Neurology, College of Physicians and Surgeons, Columbia University, The New York Presbyterian Hospital, New York, NY, 10032, USA
| | - Erin L Heinzen
- Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
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12
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Shen YI, Cheng KC, Wei YJ, Lee IR. Structural Dynamics Role of AGG Interruptions in Inhibition CGG Repeat Expansion Associated with Fragile X Syndrome. ACS Chem Neurosci 2024; 15:230-235. [PMID: 38133821 DOI: 10.1021/acschemneuro.3c00712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Abstract
Abnormal expansion of trinucleotide CGG repeats is responsible for Fragile X syndrome. AGG interruptions in CGG repeat tracts were found in most healthy individuals, suggesting a crucial role in preventing disease-prone repeat expansion. Previous biophysics studies emphasize a difference in the secondary structure affected by AGG interruptions. However, the mechanism of how AGG interruptions impede repeat expansion remains elusive. We utilized single-molecule fluorescence resonance energy transfer spectroscopy to investigate the structural dynamics of CGG repeats and their AGG-interrupted variants. Tandem CGG repeats fold into a stem-loop hairpin structure with the capability to undergo a conformational rearrangement to modulate the length of the overhang. However, this conformational rearrangement is much more retarded when two AGG interruptions are present. Considering the significance of hairpin slippage in repeat expansion, we present a molecular basis suggesting that the internal loop created by two AGG interruptions acts as a barrier, obstructing the hairpin slippage reconfiguration. This impediment potentially plays a crucial role in curbing abnormal expansion, thereby contributing to the genomic stability.
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Affiliation(s)
- Yang-I Shen
- Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan
| | - Kai-Chun Cheng
- Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan
| | - Yu-Jie Wei
- Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan
| | - I-Ren Lee
- Department of Chemistry, National Taiwan Normal University, Taipei 116, Taiwan
- Genomics Research Center, Academia Sinica, Taipei 115, Taiwan
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13
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Chen Q, Yamada T, Miyagawa K, Murata A, Shoji M, Nakatani K. A new small molecule DoNA binding to CAG repeat RNA. Bioorg Med Chem 2024; 98:117580. [PMID: 38194737 DOI: 10.1016/j.bmc.2023.117580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/23/2023] [Accepted: 12/24/2023] [Indexed: 01/11/2024]
Abstract
We here report a new molecule DoNA binding to a CAG repeat RNA. DoNA is a dimer of the NA molecule that we previously reported. NA binds with high affinity to a CAG repeat DNA but not significantly to a CAG repeat RNA. Binding analyses using SPR and CSI-TOF MS indicated a significant increase in the affinity of DoNA to a single stranded CAG repeat RNA compared to NA. Systematic investigation of the RNA motifs bound by DoNA using hairpin RNA models revealed that DoNA binds to the CAG units at overhang and terminal positions, and notably, it binds to the structurally flexible internal and hairpin loop region.
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Affiliation(s)
- Qingwen Chen
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan
| | - Takeshi Yamada
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan; Current address: Nucleotide and Peptide Drug Discovery Center, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Koichi Miyagawa
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Asako Murata
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan; Current address: Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - Mitsuo Shoji
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan
| | - Kazuhiko Nakatani
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan.
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14
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Gadgil RY, Rider SD, Shrestha R, Alhawach V, Hitch DC, Leffak M. Microsatellite break-induced replication generates highly mutagenized extrachromosomal circular DNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575055. [PMID: 38260482 PMCID: PMC10802558 DOI: 10.1101/2024.01.12.575055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Extrachromosomal circular DNAs (eccDNAs) are produced from all regions of the eucaryotic genome. In tumors, highly transcribed eccDNAs have been implicated in oncogenesis, neoantigen production and resistance to chemotherapy. Here we show that unstable microsatellites capable of forming hairpin, triplex, quadruplex and AT-rich structures generate eccDNAs when integrated at a common ectopic site in human cells. These non-B DNA prone microsatellites form eccDNAs by replication-dependent mechanisms. The microsatellite-based eccDNAs are highly mutagenized and display template switches to sister chromatids and to nonallelic chromosomal sites. High frequency mutagenesis occurs within the eccDNA microsatellites and extends bidirectionally for several kilobases into flanking DNA and nonallelic DNA. Mutations include mismatches, short duplications, longer nontemplated insertions and large deletions. Template switching leads to recurrent deletions and recombination domains within the eccDNAs. Template switching events are microhomology-mediated, but do not occur at all potential sites of complementarity. Each microsatellite exhibits a distinct pattern of recombination, microhomology choice and base substitution signature. Depletion of Rad51, the COPS2 signalosome subunit or POLη alter the eccDNA mutagenic profiles. We propose an asynchronous capture model based on break-induced replication from microsatellite-induced DNA breaks for the generation and circularization of mutagenized eccDNAs and genomic homologous recombination deficiency (HRD) scars.
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15
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Krause A, Anderson DG, Ferreira-Correia A, Dawson J, Baine-Savanhu F, Li PP, Margolis RL. Huntington disease-like 2: insight into neurodegeneration from an African disease. Nat Rev Neurol 2024; 20:36-49. [PMID: 38114648 DOI: 10.1038/s41582-023-00906-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2023] [Indexed: 12/21/2023]
Abstract
Huntington disease (HD)-like 2 (HDL2) is a rare genetic disease caused by an expanded trinucleotide repeat in the JPH3 gene (encoding junctophilin 3) that shows remarkable clinical similarity to HD. To date, HDL2 has been reported only in patients with definite or probable African ancestry. A single haplotype background is shared by patients with HDL2 from different populations, supporting a common African origin for the expansion mutation. Nevertheless, outside South Africa, reports of patients with HDL2 in Africa are scarce, probably owing to limited clinical services across the continent. Systematic comparisons of HDL2 and HD have revealed closely overlapping motor, cognitive and psychiatric features and similar patterns of cerebral and striatal atrophy. The pathogenesis of HDL2 remains unclear but it is proposed to occur through several mechanisms, including loss of protein function and RNA and/or protein toxicity. This Review summarizes our current knowledge of this African-specific HD phenocopy and highlights key areas of overlap between HDL2 and HD. Given the aforementioned similarities in clinical phenotype and pathology, an improved understanding of HDL2 could provide novel insights into HD and other neurodegenerative and/or trinucleotide repeat expansion disorders.
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Affiliation(s)
- Amanda Krause
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - David G Anderson
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- University of Glasgow, Department of Neurology, Institute of Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, UK
| | - Aline Ferreira-Correia
- Department of Psychology, School of Human and Community Development, Faculty of Humanities, University of the Witwatersrand, Johannesburg, South Africa
| | - Jessica Dawson
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Fiona Baine-Savanhu
- Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Pan P Li
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Russell L Margolis
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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16
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Malachowski T, Chandradoss KR, Boya R, Zhou L, Cook AL, Su C, Pham K, Haws SA, Kim JH, Ryu HS, Ge C, Luppino JM, Nguyen SC, Titus KR, Gong W, Wallace O, Joyce EF, Wu H, Rojas LA, Phillips-Cremins JE. Spatially coordinated heterochromatinization of long synaptic genes in fragile X syndrome. Cell 2023; 186:5840-5858.e36. [PMID: 38134876 PMCID: PMC10794044 DOI: 10.1016/j.cell.2023.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 07/31/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023]
Abstract
Short tandem repeat (STR) instability causes transcriptional silencing in several repeat expansion disorders. In fragile X syndrome (FXS), mutation-length expansion of a CGG STR represses FMR1 via local DNA methylation. Here, we find megabase-scale H3K9me3 domains on autosomes and encompassing FMR1 on the X chromosome in FXS patient-derived iPSCs, iPSC-derived neural progenitors, EBV-transformed lymphoblasts, and brain tissue with mutation-length CGG expansion. H3K9me3 domains connect via inter-chromosomal interactions and demarcate severe misfolding of TADs and loops. They harbor long synaptic genes replicating at the end of S phase, replication-stress-induced double-strand breaks, and STRs prone to stepwise somatic instability. CRISPR engineering of the mutation-length CGG to premutation length reverses H3K9me3 on the X chromosome and multiple autosomes, refolds TADs, and restores gene expression. H3K9me3 domains can also arise in normal-length iPSCs created with perturbations linked to genome instability, suggesting their relevance beyond FXS. Our results reveal Mb-scale heterochromatinization and trans interactions among loci susceptible to instability.
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Affiliation(s)
- Thomas Malachowski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Keerthivasan Raanin Chandradoss
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Boya
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Linda Zhou
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ashley L Cook
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chuanbin Su
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth Pham
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Spencer A Haws
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ji Hun Kim
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Han-Seul Ryu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chunmin Ge
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer M Luppino
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Son C Nguyen
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Katelyn R Titus
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Wanfeng Gong
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Owen Wallace
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | - Eric F Joyce
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Hao Wu
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | | | - Jennifer E Phillips-Cremins
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
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17
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Li J, Wang H, Yang W. Tandem MutSβ binding to long extruded DNA trinucleotide repeats underpins pathogenic expansions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.12.571350. [PMID: 38168405 PMCID: PMC10760016 DOI: 10.1101/2023.12.12.571350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Expansion of trinucleotide repeats causes Huntington's disease, Fragile X syndrome and over twenty other monogenic disorders1. How mismatch repair protein MutSβ and large repeats of CNG (N=A, T, C or G) cooperate to drive the expansion is poorly understood. Contrary to expectations, we find that MutSβ prefers to bind the stem of an extruded (CNG) hairpin rather than the hairpin end or hairpin-duplex junction. Structural analyses reveal that in the presence of MutSβ, CNG repeats with N:N mismatches adopt a B form-like pseudo-duplex, with one or two CNG repeats slipped out forming uneven bubbles that partly mimic insertion-deletion loops of mismatched DNA2. When the extruded hairpin exceeds 40-45 repeats, it can be bound by three or more MutSβ molecules, which are resistant to ATP-dependent dissociation. We envision that such MutSβ-CNG complexes recruit MutLγ endonuclease to nick DNA and initiate the repeat expansion process3,4. To develop drugs against the expansion diseases, we have identified lead compounds that prevent MutSβ binding to CNG repeats but not to mismatched DNA.
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Affiliation(s)
- Jun Li
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892
| | - Huaibin Wang
- Laboratory of Cell and Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892
| | - Wei Yang
- Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, MD 20892
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18
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Medina-Rivera M, Phelps S, Sridharan M, Becker J, Lamb N, Kumar C, Sutton M, Bielinsky A, Balakrishnan L, Surtees J. Elevated MSH2 MSH3 expression interferes with DNA metabolism in vivo. Nucleic Acids Res 2023; 51:12185-12206. [PMID: 37930834 PMCID: PMC10711559 DOI: 10.1093/nar/gkad934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/30/2023] [Accepted: 10/10/2023] [Indexed: 11/08/2023] Open
Abstract
The Msh2-Msh3 mismatch repair (MMR) complex in Saccharomyces cerevisiae recognizes and directs repair of insertion/deletion loops (IDLs) up to ∼17 nucleotides. Msh2-Msh3 also recognizes and binds distinct looped and branched DNA structures with varying affinities, thereby contributing to genome stability outside post-replicative MMR through homologous recombination, double-strand break repair (DSBR) and the DNA damage response. In contrast, Msh2-Msh3 promotes genome instability through trinucleotide repeat (TNR) expansions, presumably by binding structures that form from single-stranded (ss) TNR sequences. We previously demonstrated that Msh2-Msh3 binding to 5' ssDNA flap structures interfered with Rad27 (Fen1 in humans)-mediated Okazaki fragment maturation (OFM) in vitro. Here we demonstrate that elevated Msh2-Msh3 levels interfere with DNA replication and base excision repair in vivo. Elevated Msh2-Msh3 also induced a cell cycle arrest that was dependent on RAD9 and ELG1 and led to PCNA modification. These phenotypes also required Msh2-Msh3 ATPase activity and downstream MMR proteins, indicating an active mechanism that is not simply a result of Msh2-Msh3 DNA-binding activity. This study provides new mechanistic details regarding how excess Msh2-Msh3 can disrupt DNA replication and repair and highlights the role of Msh2-Msh3 protein abundance in Msh2-Msh3-mediated genomic instability.
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Affiliation(s)
- Melisa Medina-Rivera
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Samantha Phelps
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Madhumita Sridharan
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA
| | - Jordan Becker
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Natalie A Lamb
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Charanya Kumar
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Mark D Sutton
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
| | - Anja Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Lata Balakrishnan
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN, 46202, USA
| | - Jennifer A Surtees
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo NY, 14203, USA
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19
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Ikenoshita S, Matsuo K, Yabuki Y, Kawakubo K, Asamitsu S, Hori K, Usuki S, Hirose Y, Bando T, Araki K, Ueda M, Sugiyama H, Shioda N. A cyclic pyrrole-imidazole polyamide reduces pathogenic RNA in CAG/CTG triplet repeat neurological disease models. J Clin Invest 2023; 133:e164792. [PMID: 37707954 PMCID: PMC10645379 DOI: 10.1172/jci164792] [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: 08/24/2022] [Accepted: 09/12/2023] [Indexed: 09/16/2023] Open
Abstract
Expansion of CAG and CTG (CWG) triplet repeats causes several inherited neurological diseases. The CWG repeat diseases are thought to involve complex pathogenic mechanisms through expanded CWG repeat-derived RNAs in a noncoding region and polypeptides in a coding region, respectively. However, an effective therapeutic approach has not been established for the CWG repeat diseases. Here, we show that a CWG repeat DNA-targeting compound, cyclic pyrrole-imidazole polyamide (CWG-cPIP), suppressed the pathogenesis of coding and noncoding CWG repeat diseases. CWG-cPIP bound to the hairpin form of mismatched CWG DNA, interfering with transcription elongation by RNA polymerase through a preferential activity toward repeat-expanded DNA. We found that CWG-cPIP selectively inhibited pathogenic mRNA transcripts from expanded CWG repeats, reducing CUG RNA foci and polyglutamine accumulation in cells from patients with myotonic dystrophy type 1 (DM1) and Huntington's disease (HD). Treatment with CWG-cPIP ameliorated behavioral deficits in adeno-associated virus-mediated CWG repeat-expressing mice and in a genetic mouse model of HD, without cytotoxicity or off-target effects. Together, we present a candidate compound that targets expanded CWG repeat DNA independently of its genomic location and reduces both pathogenic RNA and protein levels. CWG-cPIP may be used for the treatment of CWG repeat diseases and improvement of clinical outcomes.
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Affiliation(s)
- Susumu Ikenoshita
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
- Department of Neurology, Graduate School of Medical Sciences
| | - Kazuya Matsuo
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
| | - Yasushi Yabuki
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
- Graduate School of Pharmaceutical Sciences, and
| | - Kosuke Kawakubo
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
- Graduate School of Pharmaceutical Sciences, and
| | - Sefan Asamitsu
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
| | - Karin Hori
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
| | - Shingo Usuki
- Liaison Laboratory Research Promotion Center, IMEG, Kumamoto University, Kumamoto, Japan
| | - Yuki Hirose
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Toshikazu Bando
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Kimi Araki
- Institute of Resource Development and Analysis and
- Center for Metabolic Regulation of Healthy Aging, Kumamoto University, Kumamoto, Japan
| | - Mitsuharu Ueda
- Department of Neurology, Graduate School of Medical Sciences
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan
- Institute for Integrated Cell-Material Science (iCeMS), Kyoto University, Kyoto, Japan
| | - Norifumi Shioda
- Department of Genomic Neurology, Institute of Molecular Embryology and Genetics (IMEG)
- Graduate School of Pharmaceutical Sciences, and
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20
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Rastokina A, Cebrián J, Mozafari N, Mandel NH, Smith CI, Lopes M, Zain R, Mirkin S. Large-scale expansions of Friedreich's ataxia GAA•TTC repeats in an experimental human system: role of DNA replication and prevention by LNA-DNA oligonucleotides and PNA oligomers. Nucleic Acids Res 2023; 51:8532-8549. [PMID: 37216608 PMCID: PMC10484681 DOI: 10.1093/nar/gkad441] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 05/02/2023] [Accepted: 05/20/2023] [Indexed: 05/24/2023] Open
Abstract
Friedreich's ataxia (FRDA) is caused by expansions of GAA•TTC repeats in the first intron of the human FXN gene that occur during both intergenerational transmissions and in somatic cells. Here we describe an experimental system to analyze large-scale repeat expansions in cultured human cells. It employs a shuttle plasmid that can replicate from the SV40 origin in human cells or be stably maintained in S. cerevisiae utilizing ARS4-CEN6. It also contains a selectable cassette allowing us to detect repeat expansions that accumulated in human cells upon plasmid transformation into yeast. We indeed observed massive expansions of GAA•TTC repeats, making it the first genetically tractable experimental system to study large-scale repeat expansions in human cells. Further, GAA•TTC repeats stall replication fork progression, while the frequency of repeat expansions appears to depend on proteins implicated in replication fork stalling, reversal, and restart. Locked nucleic acid (LNA)-DNA mixmer oligonucleotides and peptide nucleic acid (PNA) oligomers, which interfere with triplex formation at GAA•TTC repeats in vitro, prevented the expansion of these repeats in human cells. We hypothesize, therefore, that triplex formation by GAA•TTC repeats stall replication fork progression, ultimately leading to repeat expansions during replication fork restart.
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Affiliation(s)
| | - Jorge Cebrián
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Negin Mozafari
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
| | | | - C I Edvard Smith
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich 8057, Switzerland
| | - Rula Zain
- Department of Laboratory Medicine, Translational Research Center Karolinska (TRACK), Karolinska Institutet, Karolinska University Hospital, SE-171 77 Stockholm, Sweden
- Center for Rare Diseases, Karolinska University Hospital, SE-17176 Stockholm, Sweden
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA
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21
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Liu H, Tsai H, Yang M, Li G, Bian Q, Ding G, Wu D, Dai J. Three-dimensional genome structure and function. MedComm (Beijing) 2023; 4:e326. [PMID: 37426677 PMCID: PMC10329473 DOI: 10.1002/mco2.326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 05/31/2023] [Accepted: 06/09/2023] [Indexed: 07/11/2023] Open
Abstract
Linear DNA undergoes a series of compression and folding events, forming various three-dimensional (3D) structural units in mammalian cells, including chromosomal territory, compartment, topologically associating domain, and chromatin loop. These structures play crucial roles in regulating gene expression, cell differentiation, and disease progression. Deciphering the principles underlying 3D genome folding and the molecular mechanisms governing cell fate determination remains a challenge. With advancements in high-throughput sequencing and imaging techniques, the hierarchical organization and functional roles of higher-order chromatin structures have been gradually illuminated. This review systematically discussed the structural hierarchy of the 3D genome, the effects and mechanisms of cis-regulatory elements interaction in the 3D genome for regulating spatiotemporally specific gene expression, the roles and mechanisms of dynamic changes in 3D chromatin conformation during embryonic development, and the pathological mechanisms of diseases such as congenital developmental abnormalities and cancer, which are attributed to alterations in 3D genome organization and aberrations in key structural proteins. Finally, prospects were made for the research about 3D genome structure, function, and genetic intervention, and the roles in disease development, prevention, and treatment, which may offer some clues for precise diagnosis and treatment of related diseases.
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Affiliation(s)
- Hao Liu
- Department of Oral and Cranio‐Maxillofacial SurgeryShanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineCollege of Stomatology, Shanghai Jiao Tong UniversityNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyShanghaiChina
- School of StomatologyWeifang Medical UniversityWeifangChina
| | - Hsiangyu Tsai
- Department of Oral and Cranio‐Maxillofacial SurgeryShanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineCollege of Stomatology, Shanghai Jiao Tong UniversityNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyShanghaiChina
| | - Maoquan Yang
- School of Clinical MedicineWeifang Medical UniversityWeifangChina
| | - Guozhi Li
- Department of Oral and Cranio‐Maxillofacial SurgeryShanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineCollege of Stomatology, Shanghai Jiao Tong UniversityNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyShanghaiChina
| | - Qian Bian
- Shanghai Institute of Precision MedicineShanghaiChina
| | - Gang Ding
- School of StomatologyWeifang Medical UniversityWeifangChina
| | - Dandan Wu
- Department of Oral and Cranio‐Maxillofacial SurgeryShanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineCollege of Stomatology, Shanghai Jiao Tong UniversityNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyShanghaiChina
| | - Jiewen Dai
- Department of Oral and Cranio‐Maxillofacial SurgeryShanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineCollege of Stomatology, Shanghai Jiao Tong UniversityNational Center for StomatologyNational Clinical Research Center for Oral DiseasesShanghai Key Laboratory of StomatologyShanghaiChina
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22
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Xu P, Zhang J, Pan F, Mahn C, Roland C, Sagui C, Weninger K. Frustration Between Preferred States of Complementary Trinucleotide Repeat DNA Hairpins Anticorrelates with Expansion Disease Propensity. J Mol Biol 2023; 435:168086. [PMID: 37024008 PMCID: PMC10191799 DOI: 10.1016/j.jmb.2023.168086] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/21/2023] [Accepted: 03/30/2023] [Indexed: 04/08/2023]
Abstract
DNA trinucleotide repeat (TRs) expansion beyond a threshold often results in human neurodegenerative diseases. The mechanisms causing expansions remain unknown, although the tendency of TR ssDNA to self-associate into hairpins that slip along their length is widely presumed related. Here we apply single molecule FRET (smFRET) experiments and molecular dynamics simulations to determine conformational stabilities and slipping dynamics for CAG, CTG, GAC and GTC hairpins. Tetraloops are favored in CAG (89%), CTG (89%) and GTC (69%) while GAC favors triloops. We also determined that TTG interrupts near the loop in the CTG hairpin stabilize the hairpin against slipping. The different loop stabilities have implications for intermediate structures that may form when TR-containing duplex DNA opens. Opposing hairpins in the (CAG) ∙ (CTG) duplex would have matched stability whereas opposing hairpins in a (GAC) ∙ (GTC) duplex would have unmatched stability, introducing frustration in the (GAC) ∙ (GTC) opposing hairpins that could encourage their resolution to duplex DNA more rapidly than in (CAG) ∙ (CTG) structures. Given that the CAG and CTG TR can undergo large, disease-related expansion whereas the GAC and GTC sequences do not, these stability differences can inform and constrain models of expansion mechanisms of TR regions.
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Affiliation(s)
- Pengning Xu
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA. https://twitter.com/@XPengning
| | - Jiahui Zhang
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Feng Pan
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Chelsea Mahn
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Christopher Roland
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA
| | - Celeste Sagui
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
| | - Keith Weninger
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA.
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23
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Choi DE, Shin JW, Zeng S, Hong EP, Jang JH, Loupe JM, Wheeler VC, Stutzman HE, Kleinstiver BP, Lee JM. Base editing strategies to convert CAG to CAA diminish the disease-causing mutation in Huntington's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.28.538700. [PMID: 37162872 PMCID: PMC10168301 DOI: 10.1101/2023.04.28.538700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
An expanded CAG repeat in the huntingtin gene ( HTT ) causes Huntington's disease (HD). Since the length of uninterrupted CAG repeat, not polyglutamine, determines the age-at-onset in HD, base editing strategies to convert CAG to CAA are anticipated to delay onset by shortening the uninterrupted CAG repeat. Here, we developed base editing strategies to convert CAG in the repeat to CAA and determined their molecular outcomes and effects on relevant disease phenotypes. Base editing strategies employing combinations of cytosine base editors and gRNAs efficiently converted CAG to CAA at various sites in the CAG repeat without generating significant indels, off-target edits, or transcriptome alterations, demonstrating their feasibility and specificity. Candidate BE strategies converted CAG to CAA on both expanded and non-expanded CAG repeats without altering HTT mRNA and protein levels. In addition, somatic CAG repeat expansion, which is the major disease driver in HD, was significantly decreased by a candidate BE strategy treatment in HD knock-in mice carrying canonical CAG repeats. Notably, CAG repeat expansion was abolished entirely in HD knock-in mice carrying CAA-interrupted repeats, supporting the therapeutic potential of CAG-to-CAA conversion base editing strategies in HD and potentially other repeat expansion disorders.
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24
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Carnie CJ, Armstrong L, Sebesta M, Ariza A, Wang X, Graham E, Zhu K, Ahel D. ERCC6L2 mitigates replication stress and promotes centromere stability. Cell Rep 2023; 42:112329. [PMID: 37014751 DOI: 10.1016/j.celrep.2023.112329] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 01/26/2023] [Accepted: 03/20/2023] [Indexed: 04/05/2023] Open
Abstract
Structurally complex genomic regions, such as centromeres, are inherently difficult to duplicate. The mechanism behind centromere inheritance is not well understood, and one of the key questions relates to the reassembly of centromeric chromatin following DNA replication. Here, we define ERCC6L2 as a key regulator of this process. ERCC6L2 accumulates at centromeres and promotes deposition of core centromeric factors. Interestingly, ERCC6L2-/- cells show unrestrained replication of centromeric DNA, likely caused by the erosion of centromeric chromatin. Beyond centromeres, ERCC6L2 facilitates replication at genomic repeats and non-canonical DNA structures. Notably, ERCC6L2 interacts with the DNA-clamp PCNA through an atypical peptide, presented here in a co-crystal structure. Finally, ERCC6L2 also restricts DNA end resection, acting independently of the 53BP1-REV7-Shieldin complex. We propose a mechanistic model, which reconciles seemingly distinct functions of ERCC6L2 in DNA repair and DNA replication. These findings provide a molecular context for studies linking ERCC6L2 to human disease.
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Affiliation(s)
| | - Lucy Armstrong
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Marek Sebesta
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Antonio Ariza
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Xiaomeng Wang
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Emily Graham
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Kang Zhu
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Dragana Ahel
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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25
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Wang G, Vasquez KM. Dynamic alternative DNA structures in biology and disease. Nat Rev Genet 2023; 24:211-234. [PMID: 36316397 DOI: 10.1038/s41576-022-00539-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
Repetitive elements in the human genome, once considered 'junk DNA', are now known to adopt more than a dozen alternative (that is, non-B) DNA structures, such as self-annealed hairpins, left-handed Z-DNA, three-stranded triplexes (H-DNA) or four-stranded guanine quadruplex structures (G4 DNA). These dynamic conformations can act as functional genomic elements involved in DNA replication and transcription, chromatin organization and genome stability. In addition, recent studies have revealed a role for these alternative structures in triggering error-generating DNA repair processes, thereby actively enabling genome plasticity. As a driving force for genetic variation, non-B DNA structures thus contribute to both disease aetiology and evolution.
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Affiliation(s)
- Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Paediatric Research Institute, Austin, TX, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Paediatric Research Institute, Austin, TX, USA.
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26
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PerezGrovas-Saltijeral A, Ochoa-Morales A, Jara-Prado A, Velázquez-Cruz R, Rivera-Paredez B, Dávila-OrtizdeMontellano D, Benítez-Alonso EO, Santamaría-Olmedo M, Sevilla-Montoya R, Marfil-Marín E, Valdés-Flores M, Martínez-Ruano L, Camacho-Molina A, Hidalgo-Bravo A. Unraveling the role of relative telomere length and CAG expansion on initial symptoms of juvenile Huntington disease. Eur J Neurol 2023; 30:612-621. [PMID: 36421025 DOI: 10.1111/ene.15644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND PURPOSE Juvenile-onset Huntington disease (JHD) is defined when symptoms initiate before 20 years of age. Mechanisms explaining differences between juvenile and adult onset are not fully understood. Our aim was to analyze the distribution of initial symptoms in a cohort of JHD patients and to explore its relationship with CAG expansion and relative telomere length (RTL). METHODS A total of 84 JHD patients and 54 neurologically healthy age and sex matched individuals were recruited. CAG length was measured by southern blot or triplet repeat primed polymerase chain reaction. RTL was measured using the Cawthon method. RESULTS Psychiatric symptoms were most frequent when considering the entire cohort. When divided into onset before or after 10 years, cognitive symptoms were more frequent in the youngest, whilst in the older group psychiatric symptoms prevailed. Motor symptoms were rare in the youngest and epilepsy was observed only in this group as well as a larger CAG expansion. RTL analysis revealed shorter telomeres in JHD patients compared to controls. This difference is not influenced by age, initial symptoms, time of disease or CAG expansion. CONCLUSIONS To the best of our knowledge this is the largest cohort of JHD patients reported. Psychiatric manifestations deserve special attention when JHD is suspected and epilepsy is especially important in the youngest patients. Initial symptoms seem to be influenced by CAG expansion and therefore age of onset. RTL is significantly reduced in JHD patients which can influence the characteristic neurodegeneration of JHD and contribute to the clinical discrepancy between adult and juvenile forms of Huntington disease.
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Affiliation(s)
| | - Adriana Ochoa-Morales
- Department of Neurogenetics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Aurelio Jara-Prado
- Department of Neurogenetics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Rafael Velázquez-Cruz
- Genomics of Bone Metabolism Laboratory, National Institute of Genomic Medicine (INMEGEN), Mexico City, Mexico
| | - Berenice Rivera-Paredez
- Research Center in Policies, Population and Health, School of Medicine, National Autonomous University of Mexico (UNAM), Mexico City, Mexico
| | | | - Edmar O Benítez-Alonso
- Department of Neurogenetics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | | | - Rosalba Sevilla-Montoya
- Department of Genetics and Human Genomics, National Institute of Perinatology, Mexico City, Mexico
| | | | | | - Leticia Martínez-Ruano
- Department of Neurogenetics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | - Alejandra Camacho-Molina
- Department of Neurogenetics, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
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27
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Calluori S, Stark R, Pearson BL. Gene-Environment Interactions in Repeat Expansion Diseases: Mechanisms of Environmentally Induced Repeat Instability. Biomedicines 2023; 11:515. [PMID: 36831049 PMCID: PMC9953593 DOI: 10.3390/biomedicines11020515] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
Short tandem repeats (STRs) are units of 1-6 base pairs that occur in tandem repetition to form a repeat tract. STRs exhibit repeat instability, which generates expansions or contractions of the repeat tract. Over 50 diseases, primarily affecting the central nervous system and muscles, are characterized by repeat instability. Longer repeat tracts are typically associated with earlier age of onset and increased disease severity. Environmental exposures are suspected to play a role in the pathogenesis of repeat expansion diseases. Here, we review the current knowledge of mechanisms of environmentally induced repeat instability in repeat expansion diseases. The current evidence demonstrates that environmental factors modulate repeat instability via DNA damage and induction of DNA repair pathways, with distinct mechanisms for repeat expansion and contraction. Of particular note, oxidative stress is a key mediator of environmentally induced repeat instability. The preliminary evidence suggests epigenetic modifications as potential mediators of environmentally induced repeat instability. Future research incorporating an array of environmental exposures, new human cohorts, and improved model systems, with a continued focus on cell-types, tissues, and critical windows, will aid in identifying mechanisms of environmentally induced repeat instability. Identifying environmental modulators of repeat instability and their mechanisms of action will inform preventions, therapies, and public health measures.
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Affiliation(s)
- Stephanie Calluori
- Department of Environmental Health Sciences, Mailman School of Public Health Columbia University, New York, NY 10032, USA
- Barnard College of Columbia University, 3009 Broadway, New York, NY 10027, USA
| | - Rebecca Stark
- Department of Environmental Health Sciences, Mailman School of Public Health Columbia University, New York, NY 10032, USA
| | - Brandon L. Pearson
- Department of Environmental Health Sciences, Mailman School of Public Health Columbia University, New York, NY 10032, USA
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28
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Teng Y, Zhu M, Qiu Z. G-Quadruplexes in Repeat Expansion Disorders. Int J Mol Sci 2023; 24:ijms24032375. [PMID: 36768697 PMCID: PMC9916761 DOI: 10.3390/ijms24032375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/27/2023] Open
Abstract
The repeat expansions are the main genetic cause of various neurodegeneration diseases. More than ten kinds of repeat sequences with different lengths, locations, and structures have been confirmed in the past two decades. G-rich repeat sequences, such as CGG and GGGGCC, are reported to form functional G-quadruplexes, participating in many important bioprocesses. In this review, we conducted an overview concerning the contribution of G-quadruplex in repeat expansion disorders and summarized related mechanisms in current pathological studies, including the increasing genetic instabilities in replication and transcription, the toxic RNA foci formed in neurons, and the loss/gain function of proteins and peptides. Furthermore, novel strategies targeting G-quadruplex repeats were developed based on the understanding of disease mechanism. Small molecules and proteins binding to G-quadruplex in repeat expansions were investigated to protect neurons from dysfunction and delay the progression of neurodegeneration. In addition, the effects of environment on the stability of G-quadruplex were discussed, which might be critical factors in the pathological study of repeat expansion disorders.
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29
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Rare tandem repeat expansions associate with genes involved in synaptic and neuronal signaling functions in schizophrenia. Mol Psychiatry 2023; 28:475-482. [PMID: 36380236 PMCID: PMC9812781 DOI: 10.1038/s41380-022-01857-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 10/14/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022]
Abstract
Tandem repeat expansions (TREs) are associated with over 60 monogenic disorders and have recently been implicated in complex disorders such as cancer and autism spectrum disorder. The role of TREs in schizophrenia is now emerging. In this study, we have performed a genome-wide investigation of TREs in schizophrenia. Using genome sequence data from 1154 Swedish schizophrenia cases and 934 ancestry-matched population controls, we have detected genome-wide rare (<0.1% population frequency) TREs that have motifs with a length of 2-20 base pairs. We find that the proportion of individuals carrying rare TREs is significantly higher in the schizophrenia group. There is a significantly higher burden of rare TREs in schizophrenia cases than in controls in genic regions, particularly in postsynaptic genes, in genes overlapping brain expression quantitative trait loci, and in brain-expressed genes that are differentially expressed between schizophrenia cases and controls. We demonstrate that TRE-associated genes are more constrained and primarily impact synaptic and neuronal signaling functions. These results have been replicated in an independent Canadian sample that consisted of 252 schizophrenia cases of European ancestry and 222 ancestry-matched controls. Our results support the involvement of rare TREs in schizophrenia etiology.
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30
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Khan ES, Danckwardt S. Pathophysiological Role and Diagnostic Potential of R-Loops in Cancer and Beyond. Genes (Basel) 2022; 13:genes13122181. [PMID: 36553448 PMCID: PMC9777984 DOI: 10.3390/genes13122181] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 11/24/2022] Open
Abstract
R-loops are DNA-RNA hybrids that play multifunctional roles in gene regulation, including replication, transcription, transcription-replication collision, epigenetics, and preserving the integrity of the genome. The aberrant formation and accumulation of unscheduled R-loops can disrupt gene expression and damage DNA, thereby causing genome instability. Recent links between unscheduled R-loop accumulation and the abundance of proteins that modulate R-loop biogenesis have been associated with numerous human diseases, including various cancers. Although R-loops are not necessarily causative for all disease entities described to date, they can perpetuate and even exacerbate the initially disease-eliciting pathophysiology, making them structures of interest for molecular diagnostics. In this review, we discuss the (patho) physiological role of R-loops in health and disease, their surprising diagnostic potential, and state-of-the-art techniques for their detection.
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Affiliation(s)
- Essak S. Khan
- Posttranscriptional Gene Regulation, Cancer Research and Experimental Hemostasis, University Medical Center Mainz, 55131 Mainz, Germany
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
- German Consortium for Translational Cancer Research (DKTK), DKFZ Frankfurt-Mainz, 60590 Frankfurt am Main, Germany
| | - Sven Danckwardt
- Posttranscriptional Gene Regulation, Cancer Research and Experimental Hemostasis, University Medical Center Mainz, 55131 Mainz, Germany
- Institute for Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University, 55131 Mainz, Germany
- German Center for Cardiovascular Research (DZHK), Rhine-Main, 55131 Mainz, Germany
- Correspondence:
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31
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Incebacak Eltemur RD, Nguyen HP, Weber JJ. Calpain-mediated proteolysis as driver and modulator of polyglutamine toxicity. Front Mol Neurosci 2022; 15:1020104. [PMID: 36385755 PMCID: PMC9648470 DOI: 10.3389/fnmol.2022.1020104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 09/26/2022] [Indexed: 09/22/2023] Open
Abstract
Among posttranslational modifications, directed proteolytic processes have the strongest impact on protein integrity. They are executed by a variety of cellular machineries and lead to a wide range of molecular consequences. Compared to other forms of proteolytic enzymes, the class of calcium-activated calpains is considered as modulator proteases due to their limited proteolytic activity, which changes the structure and function of their target substrates. In the context of neurodegeneration and - in particular - polyglutamine disorders, proteolytic events have been linked to modulatory effects on the molecular pathogenesis by generating harmful breakdown products of disease proteins. These findings led to the formulation of the toxic fragment hypothesis, and calpains appeared to be one of the key players and auspicious therapeutic targets in Huntington disease and Machado Joseph disease. This review provides a current survey of the role of calpains in proteolytic processes found in polyglutamine disorders. Together with insights into general concepts behind toxic fragments and findings in polyglutamine disorders, this work aims to inspire researchers to broaden and deepen the knowledge in this field, which will help to evaluate calpain-mediated proteolysis as a unifying and therapeutically targetable posttranslational mechanism in neurodegeneration.
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Affiliation(s)
- Rana Dilara Incebacak Eltemur
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
| | - Jonasz Jeremiasz Weber
- Department of Human Genetics, Ruhr University Bochum, Bochum, Germany
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
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32
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Matos-Rodrigues G, van Wietmarschen N, Wu W, Tripathi V, Koussa NC, Pavani R, Nathan WJ, Callen E, Belinky F, Mohammed A, Napierala M, Usdin K, Ansari AZ, Mirkin SM, Nussenzweig A. S1-END-seq reveals DNA secondary structures in human cells. Mol Cell 2022; 82:3538-3552.e5. [PMID: 36075220 PMCID: PMC9547894 DOI: 10.1016/j.molcel.2022.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 05/25/2022] [Accepted: 08/04/2022] [Indexed: 11/15/2022]
Abstract
DNA becomes single stranded (ssDNA) during replication, transcription, and repair. Transiently formed ssDNA segments can adopt alternative conformations, including cruciforms, triplexes, and quadruplexes. To determine whether there are stable regions of ssDNA in the human genome, we utilized S1-END-seq to convert ssDNA regions to DNA double-strand breaks, which were then processed for high-throughput sequencing. This approach revealed two predominant non-B DNA structures: cruciform DNA formed by expanded (TA)n repeats that accumulate in microsatellite unstable human cancer cell lines and DNA triplexes (H-DNA) formed by homopurine/homopyrimidine mirror repeats common across a variety of cell lines. We show that H-DNA is enriched during replication, that its genomic location is highly conserved, and that H-DNA formed by (GAA)n repeats can be disrupted by treatment with a (GAA)n-binding polyamide. Finally, we show that triplex-forming repeats are hotspots for mutagenesis. Our results identify dynamic DNA secondary structures in vivo that contribute to elevated genome instability.
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Affiliation(s)
| | | | - Wei Wu
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Veenu Tripathi
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Natasha C Koussa
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Raphael Pavani
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - William J Nathan
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Elsa Callen
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Frida Belinky
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA
| | - Ashraf Mohammed
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Marek Napierala
- Department of Neurology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390, USA
| | - Karen Usdin
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Aseem Z Ansari
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | | | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA.
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33
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Cho IK, Easley CA, Chan AWS. Suppression of trinucleotide repeat expansion in spermatogenic cells in Huntington's disease. J Assist Reprod Genet 2022; 39:2413-2430. [PMID: 36066723 PMCID: PMC9596677 DOI: 10.1007/s10815-022-02594-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022] Open
Abstract
Trinucleotide repeats (TNRs) are dispersed throughout the human genome. About 20 loci are related to human diseases, such as Huntington's disease (HD). A larger TNR instability is predominantly observed in the paternal germ cells in some TNR disorders. Suppressing the expansion during spermatogenesis can provide a unique opportunity to end the vicious cycle of genetic anticipation. Here, using an in vitro differentiation method to derive advanced spermatogenic cells, we investigated the efficacy of two therapeutic agents, araC (cytarabine) and aspirin, on stabilizing TNRs in spermatogenic cells. Two WT patient-derived induced pluripotent stem cell (iPSC) lines and two HD hiPSC lines, with 44 Q and 180 Q, were differentiated into spermatogonial stem cell-like cells (SSCLCs). Both HD cell lines showed CAG tract expansion in SSCLC. When treated with araC and aspirin, HD1 showed moderate but not statistically significant stabilization of TNR. In HD2, 10 nM of aspirin and araC showed significant stabilization of TNR. All cell lines showed increased DNA damage response (DDR) gene expression in SSCLCs while more genes were significantly induced in HD SSCLC. In HD1, araC and aspirin treatment showed general suppression of DNA damage response genes. In HD2, only FAN1, OGG1, and PCNA showed significant suppression. When the methylation profile of HD cells was analyzed, FAN1 and OGG1 showed significant hypermethylation after the aspirin and araC treatment in SSCLC compared to the control. This study underscores the utility of our in vitro spermatogenesis model to study and develop therapies for TNR disorders such as HD.
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Affiliation(s)
- In K Cho
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.
- Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, Atlanta, GA, USA.
- Department of Environmental Health Sciences, College of Public Health, University of Georgia, Athens, GA, USA.
- Regenerative Bioscience Center, University of Georgia, Athens, GA, USA.
- Environmental Health Science and Regenerative Bioscience Center, College of Public Health, University of Georgia, Edgar L. Rhodes Center for Animal and Dairy Science RM 432, 425 River Rd, Athens, GA, 30602, USA.
| | - Charles A Easley
- Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Environmental Health Sciences, College of Public Health, University of Georgia, Athens, GA, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
| | - Anthony W S Chan
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
- Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, Atlanta, GA, USA
- Center of Scientific Review (CSR), National Institutes of Health, Bethesda, USA
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34
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Masnovo C, Lobo AF, Mirkin SM. Replication dependent and independent mechanisms of GAA repeat instability. DNA Repair (Amst) 2022; 118:103385. [PMID: 35952488 PMCID: PMC9675320 DOI: 10.1016/j.dnarep.2022.103385] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/28/2022] [Accepted: 07/30/2022] [Indexed: 11/20/2022]
Abstract
Trinucleotide repeat instability is a driver of human disease. Large expansions of (GAA)n repeats in the first intron of the FXN gene are the cause Friedreich's ataxia (FRDA), a progressive degenerative disorder which cannot yet be prevented or treated. (GAA)n repeat instability arises during both replication-dependent processes, such as cell division and intergenerational transmission, as well as in terminally differentiated somatic tissues. Here, we provide a brief historical overview on the discovery of (GAA)n repeat expansions and their association to FRDA, followed by recent advances in the identification of triplex H-DNA formation and replication fork stalling. The main body of this review focuses on the last decade of progress in understanding the mechanism of (GAA)n repeat instability during DNA replication and/or DNA repair. We propose that the discovery of additional mechanisms of (GAA)n repeat instability can be achieved via both comparative approaches to other repeat expansion diseases and genome-wide association studies. Finally, we discuss the advances towards FRDA prevention or amelioration that specifically target (GAA)n repeat expansions.
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Affiliation(s)
- Chiara Masnovo
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Ayesha F Lobo
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA.
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35
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Casas-Delucchi CS, Daza-Martin M, Williams SL, Coster G. The mechanism of replication stalling and recovery within repetitive DNA. Nat Commun 2022; 13:3953. [PMID: 35853874 PMCID: PMC9296464 DOI: 10.1038/s41467-022-31657-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 06/27/2022] [Indexed: 11/09/2022] Open
Abstract
Accurate chromosomal DNA replication is essential to maintain genomic stability. Genetic evidence suggests that certain repetitive sequences impair replication, yet the underlying mechanism is poorly defined. Replication could be directly inhibited by the DNA template or indirectly, for example by DNA-bound proteins. Here, we reconstitute replication of mono-, di- and trinucleotide repeats in vitro using eukaryotic replisomes assembled from purified proteins. We find that structure-prone repeats are sufficient to impair replication. Whilst template unwinding is unaffected, leading strand synthesis is inhibited, leading to fork uncoupling. Synthesis through hairpin-forming repeats is rescued by replisome-intrinsic mechanisms, whereas synthesis of quadruplex-forming repeats requires an extrinsic accessory helicase. DNA-induced fork stalling is mechanistically similar to that induced by leading strand DNA lesions, highlighting structure-prone repeats as an important potential source of replication stress. Thus, we propose that our understanding of the cellular response to replication stress may also be applied to DNA-induced replication stalling.
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Affiliation(s)
- Corella S Casas-Delucchi
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Manuel Daza-Martin
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Sophie L Williams
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK
| | - Gideon Coster
- Genome Replication lab, Division of Cancer Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London, SW3 6JB, UK.
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36
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Baud A, Derbis M, Tutak K, Sobczak K. Partners in crime: Proteins implicated in
RNA
repeat expansion diseases. WIRES RNA 2022; 13:e1709. [PMID: 35229468 PMCID: PMC9539487 DOI: 10.1002/wrna.1709] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 11/06/2022]
Affiliation(s)
- Anna Baud
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Magdalena Derbis
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Katarzyna Tutak
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
| | - Krzysztof Sobczak
- Department of Gene Expression Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University Poznan Poland
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37
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Wilbertz JH, Frappier J, Muller S, Gratzer S, Englaro W, Stanek LM, Calamini B. Time-resolved FRET screening identifies small molecular modifiers of mutant Huntingtin conformational inflexibility in patient-derived cells. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:219-228. [PMID: 35058188 DOI: 10.1016/j.slasd.2021.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Huntington's disease (HD) is the most common monogenic neurodegenerative disease and is fatal. CAG repeat expansions in mutant Huntingtin (mHTT) exon 1 encode for polyglutamine (polyQ) stretches and influence age of onset and disease severity, depending on their length. mHTT is more structured compared to wild-type (wt) HTT, resulting in a decreased N-terminal conformational flexibility. mHTT inflexibility may contribute to both gain of function toxicity, due to increased mHTT aggregation propensity, but also to loss of function phenotypes, due to decreased interactions with binding partners. High-throughput-screening techniques to identify mHTT flexibility states and potential flexibility modifying small molecules are currently lacking. Here, we propose a novel approach for identifying small molecules that restore mHTT's conformational flexibility in human patient fibroblasts. We have applied a well-established antibody-based time-resolved Förster resonance energy transfer (TR-FRET) immunoassay, which measures endogenous HTT flexibility using two validated HTT-specific antibodies, to a high-throughput screening platform. By performing a small-scale compound screen, we identified several small molecules that can partially rescue mHTT inflexibility, presumably by altering HTT post-translational modifications. Thus, we demonstrated that the HTT TR-FRET immunoassay can be miniaturized and applied to a compound screening workflow in patient cells. This automated assay can now be used in large screening campaigns to identify previously unknown HD drugs and drug targets.
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Affiliation(s)
| | | | | | | | | | - Lisa M Stanek
- Sanofi Rare and Neurological Diseases, Framingham, MA, United States
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38
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Lee J, Li K, Zimmerman SC. A Selective Alkylating Agent for CTG Repeats in Myotonic Dystrophy Type 1. ACS Chem Biol 2022; 17:1103-1110. [PMID: 35483041 DOI: 10.1021/acschembio.1c00949] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Disease intervention at the DNA level generally has been avoided because of off-target effects. Recent advances in genome editing technologies using CRISPR-Cas9 have opened a new era in DNA-targeted therapeutic approaches. However, delivery of such systems remains a major challenge. Here, we report a selective DNA-modifying small molecule that targets a disease-specific structure and mismatches involved in myotonic dystrophy type 1 (DM1). This ligand alkylates T-T mismatch-containing hairpins formed in the expanded CTG repeats (d(CTG)exp) in DM1. Ligand alkylation of d(CTG)exp inhibits the transcription of d(CAG·CTG)exp, thereby reducing the level of the toxic r(CUG)exp transcript. The bioactivity of the ligand also included a reduction in DM1 pathological features such as disease foci formation and misregulation of pre-mRNA splicing in DM1 model cells. Furthermore, the CTG-alkylating ligand may change the d(CAG·CTG)exp repeat length dynamics in DM1 patient cells. Our strategy of linking an alkylating moiety to a DNA mismatch-selective small molecule may be generally applicable to other repeat expansion diseases such as Huntington's disease and amyotrophic lateral sclerosis.
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Affiliation(s)
- JuYeon Lee
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ke Li
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Steven C. Zimmerman
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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39
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Fakharzadeh A, Zhang J, Roland C, Sagui C. Novel eGZ-motif formed by regularly extruded guanine bases in a left-handed Z-DNA helix as a major motif behind CGG trinucleotide repeats. Nucleic Acids Res 2022; 50:4860-4876. [PMID: 35536254 PMCID: PMC9122592 DOI: 10.1093/nar/gkac339] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/19/2022] [Accepted: 05/05/2022] [Indexed: 12/19/2022] Open
Abstract
The expansion of d(CGG) trinucleotide repeats (TRs) lies behind several important neurodegenerative diseases. Atypical DNA secondary structures have been shown to trigger TR expansion: their characterization is important for a molecular understanding of TR disease. CD spectroscopy experiments in the last decade have unequivocally demonstrated that CGG runs adopt a left-handed Z-DNA conformation, whose features remain uncertain because it entails accommodating GG mismatches. In order to find this missing motif, we have carried out molecular dynamics (MD) simulations to explore all the possible Z-DNA helices that potentially form after the transition from B- to Z-DNA. Such helices combine either CpG or GpC Watson-Crick steps in Z-DNA form with GG-mismatch conformations set as either intrahelical or extrahelical; and participating in BZ or ZZ junctions or in alternately extruded conformations. Characterization of the stability and structural features (especially overall left-handedness, higher-temperature and steered MD simulations) identified two novel Z-DNA helices: the most stable one displays alternately extruded Gs, and is followed by a helix with symmetrically extruded ZZ junctions. The G-extrusion favors a seamless stacking of the Watson-Crick base pairs; extruded Gs favor syn conformations and display hydrogen-bonding and stacking interactions. Such conformations could have the potential to hijack the MMR complex, thus triggering further expansion.
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Affiliation(s)
- Ashkan Fakharzadeh
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Jiahui Zhang
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Christopher Roland
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
| | - Celeste Sagui
- Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, USA
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40
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Tabolacci E, Nobile V, Pucci C, Chiurazzi P. Mechanisms of the FMR1 Repeat Instability: How Does the CGG Sequence Expand? Int J Mol Sci 2022; 23:ijms23105425. [PMID: 35628235 PMCID: PMC9141726 DOI: 10.3390/ijms23105425] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 11/16/2022] Open
Abstract
A dynamic mutation in exon 1 of the FMR1 gene causes Fragile X-related Disorders (FXDs), due to the expansion of an unstable CGG repeat sequence. Based on the CGG sequence size, two types of FMR1 alleles are possible: “premutation” (PM, with 56-200 CGGs) and “full mutation” (FM, with >200 triplets). Premutated females are at risk of transmitting a FM allele that, when methylated, epigenetically silences FMR1 and causes Fragile X syndrome (FXS), a very common form of inherited intellectual disability (ID). Expansions events of the CGG sequence are predominant over contractions and are responsible for meiotic and mitotic instability. The CGG repeat usually includes one or more AGG interspersed triplets that influence allele stability and the risk of transmitting FM to children through maternal meiosis. A unique mechanism responsible for repeat instability has not been identified, but several processes are under investigations using cellular and animal models. The formation of unusual secondary DNA structures at the expanded repeats are likely to occur and contribute to the CGG expansion. This review will focus on the current knowledge about CGG repeat instability addressing the CGG sequence expands.
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Affiliation(s)
- Elisabetta Tabolacci
- Dipartimento Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.)
| | - Veronica Nobile
- Dipartimento Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.)
| | - Cecilia Pucci
- Dipartimento Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.)
| | - Pietro Chiurazzi
- Dipartimento Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy; (E.T.); (V.N.); (C.P.)
- UOC Genetica Medica, Fondazione Policlinico Universitario “A. Gemelli” IRCCS, 00168 Rome, Italy
- Correspondence: ; Tel.: +39-06-3015-4606
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41
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Nguyen HT, Hori N, Thirumalai D. Condensates in RNA repeat sequences are heterogeneously organized and exhibit reptation dynamics. Nat Chem 2022; 14:775-785. [PMID: 35501484 DOI: 10.1038/s41557-022-00934-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 03/24/2022] [Indexed: 12/21/2022]
Abstract
Although it is known that RNA undergoes liquid-liquid phase separation, the interplay between the molecular driving forces and the emergent features of the condensates, such as their morphologies and dynamic properties, is not well understood. We introduce a coarse-grained model to simulate phase separation of trinucleotide repeat RNAs, which are implicated in neurological disorders. After establishing that the simulations reproduce key experimental findings, we show that once recruited inside the liquid droplets, the monomers transition from hairpin-like structures to extended states. Interactions between the monomers in the condensates result in the formation of an intricate and dense intermolecular network, which severely restrains the fluctuations and mobilities of the RNAs inside large droplets. In the largest densely packed high-viscosity droplets, the mobility of RNA chains is best characterized by reptation, reminiscent of the dynamics in polymer melts. Our work provides a microscopic framework for understanding liquid-liquid phase separation in RNA, which is not easily discernible in current experiments.
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Affiliation(s)
- Hung T Nguyen
- Department of Chemistry, The University of Texas at Austin, Austin, TX, USA
| | - Naoto Hori
- School of Pharmacy, University of Nottingham, Nottingham, UK
| | - D Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, TX, USA.
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42
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Yadav Y, Sharma SN, Shakya DK. Detection of Tandem Repeats in DNA Sequences Using Short-Time Ramanujan Fourier Transform. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2022; 19:1583-1591. [PMID: 33493119 DOI: 10.1109/tcbb.2021.3053656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tandem repeats in genomic sequences are characterized by two or more contiguous copies of a pattern of nucleotides. The role of these repeats as molecular markers is well established in various genetic disorders, human evolution studies, DNA forensics and intron retention. In this work a computational method has been developed for the extraction of both exact and approximate tandem repeats. The proposed algorithm uses Ramanujan Fourier Transform (RFT) to identify periodicities in the DNA sequences. Since RFT estimates the period directly, rather than inferring it from the signal's spectrum, it provides a more sensitive and rapid detection of tandem repeats as compared to other available popular computational methods.
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43
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Selectively recognizing extrahelical conformations of DNA trinucleotide repeats by a hydroxylated porphyrin ligand. Anal Chim Acta 2022; 1190:339265. [PMID: 34857129 DOI: 10.1016/j.aca.2021.339265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 10/06/2021] [Accepted: 11/08/2021] [Indexed: 11/24/2022]
Abstract
Trinucleotide repeats (TRs) with abnormal lengths and atypical folding are implicated in various neurodegenerative diseases. The least stable cytosine-cytosine (C-C) mismatches in TRs when structuring into homoduplexes/hairpins have more chance in certain sequence contexts to preferentially adopt an extrahelical (E-motif) conformation with respect to those in polarity-inverted intrahelical counterparts. Herein, we designed a trihydroxyphenyl porphyrin ligand (POH3) to meet the challenge towards resolving the E-motif conformation. POH3 exhibited a specific 2:1 binding with DNAs adopting the E-motif cytosine conformation, independent of the TRs length. The trihydroxyl pattern was very crucial to gain the E-motif selectivity over the polarity-inverted counterparts via the complementary hydrogen bonding that occurred in the minor groove. Our work first elucidates the rationale in designing ligands to selectively resolve the E-motif nucleotides within TRs.
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44
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Narayanaswami P, Živković S. Molecular and Genetic Therapies. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00011-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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45
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46
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Arning L, Nguyen HP. Huntington disease update: new insights into the role of repeat instability in disease pathogenesis. MED GENET-BERLIN 2021; 33:293-300. [PMID: 38835439 PMCID: PMC11006308 DOI: 10.1515/medgen-2021-2101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 11/16/2021] [Indexed: 06/06/2024]
Abstract
The causative mutation for Huntington disease (HD), an expanded trinucleotide repeat sequence in the first exon of the huntingtin gene (HTT) is naturally polymorphic and inevitably associated with disease symptoms above 39 CAG repeats. Although symptomatic medical therapies for HD can improve the motor and non-motor symptoms for affected patients, these drugs do not stop the ongoing neurodegeneration and progression of the disease, which results in severe motor and cognitive disability and death. To date, there is still an urgent need for the development of effective disease-modifying therapies to slow or even stop the progression of HD. The increasing ability to intervene directly at the roots of the disease, namely HTT transcription and translation of its mRNA, makes it necessary to understand the pathogenesis of HD as precisely as possible. In addition to the long-postulated toxicity of the polyglutamine-expanded mutant HTT protein, there is increasing evidence that the CAG repeat-containing RNA might also be directly involved in toxicity. Recent studies have identified cis- (DNA repair genes) and trans- (loss/duplication of CAA interruption) acting variants as major modifiers of age at onset (AO) and disease progression. More and more extensive data indicate that somatic instability functions as a driver for AO as well as disease progression and severity, not only in HD but also in other polyglutamine diseases. Thus, somatic expansions of repetitive DNA sequences may be essential to promote respective repeat lengths to reach a threshold leading to the overt neurodegenerative symptoms of trinucleotide diseases. These findings support somatic expansion as a potential therapeutic target in HD and related repeat expansion disorders.
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Affiliation(s)
- Larissa Arning
- Department of Human Genetics, Medical Faculty, Ruhr-University Bochum, Bochum 44780, Germany
| | - Huu Phuc Nguyen
- Department of Human Genetics, Medical Faculty, Ruhr-University Bochum, Bochum 44780, Germany
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47
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Chan KY, Li X, Ortega J, Gu L, Li GM. DNA polymerase θ promotes CAG•CTG repeat expansions in Huntington's disease via insertion sequences of its catalytic domain. J Biol Chem 2021; 297:101144. [PMID: 34473992 PMCID: PMC8463855 DOI: 10.1016/j.jbc.2021.101144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/23/2021] [Accepted: 08/27/2021] [Indexed: 12/04/2022] Open
Abstract
Huntington's disease (HD), a neurodegenerative disease characterized by progressive dementia, psychiatric problems, and chorea, is known to be caused by CAG repeat expansions in the HD gene HTT. However, the mechanism of this pathology is not fully understood. The translesion DNA polymerase θ (Polθ) carries a large insertion sequence in its catalytic domain, which has been shown to allow DNA loop-outs in the primer strand. As a result of high levels of oxidative DNA damage in neural cells and Polθ's subsequent involvement in base excision repair of oxidative DNA damage, we hypothesized that Polθ contributes to CAG repeat expansion while repairing oxidative damage within HTT. Here, we performed Polθ-catalyzed in vitro DNA synthesis using various CAG•CTG repeat DNA substrates that are similar to base excision repair intermediates. We show that Polθ efficiently extends (CAG)n•(CTG)n hairpin primers, resulting in hairpin retention and repeat expansion. Polθ also triggers repeat expansions to pass the threshold for HD when the DNA template contains 35 repeats upward. Strikingly, Polθ depleted of the catalytic insertion fails to induce repeat expansions regardless of primers and templates used, indicating that the insertion sequence is responsible for Polθ's error-causing activity. In addition, the level of chromatin-bound Polθ in HD cells is significantly higher than in non-HD cells and exactly correlates with the degree of CAG repeat expansion, implying Polθ's involvement in triplet repeat instability. Therefore, we have identified Polθ as a potent factor that promotes CAG•CTG repeat expansions in HD and other neurodegenerative disorders.
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Affiliation(s)
- Kara Y Chan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA; Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Xueying Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Janice Ortega
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Liya Gu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA; Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
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48
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Xu J, Chong J, Wang D. Strand-specific effect of Rad26 and TFIIS in rescuing transcriptional arrest by CAG trinucleotide repeat slip-outs. Nucleic Acids Res 2021; 49:7618-7627. [PMID: 34197619 PMCID: PMC8287942 DOI: 10.1093/nar/gkab573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/08/2021] [Accepted: 06/21/2021] [Indexed: 02/03/2023] Open
Abstract
Transcription induced CAG repeat instability is associated with fatal neurological disorders. Genetic approaches found transcription-coupled nucleotide excision repair (TC-NER) factor CSB protein and TFIIS play critical roles in modulating the repeat stability. Here, we took advantage of an in vitro reconstituted yeast transcription system to investigate the underlying mechanism of RNA polymerase II (Pol II) transcriptional pausing/stalling by CAG slip-out structures and the functions of TFIIS and Rad26, the yeast ortholog of CSB, in modulating transcriptional arrest. We identified length-dependent and strand-specific mechanisms that account for CAG slip-out induced transcriptional arrest. We found substantial R-loop formation for the distal transcriptional pausing induced by template strand (TS) slip-out, but not non-template strand (NTS) slip-out. In contrast, Pol II backtracking was observed at the proximal transcriptional pausing sites induced by both NTS and TS slip-out blockage. Strikingly, we revealed that Rad26 and TFIIS can stimulate bypass of NTS CAG slip-out, but not TS slip-out induced distal pausing. Our biochemical results provide new insights into understanding the mechanism of CAG slip-out induced transcriptional pausing and functions of transcription factors in modulating transcription-coupled CAG repeat instability, which may pave the way for developing potential strategies for the treatment of repeat sequence associated human diseases.
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Affiliation(s)
- Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, USA
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, USA
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences; University of California, San Diego, La Jolla, CA 92093, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
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49
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Lovergne L, Ghosh D, Schuck R, Polyzos AA, Chen AD, Martin MC, Barnard ES, Brown JB, McMurray CT. An infrared spectral biomarker accurately predicts neurodegenerative disease class in the absence of overt symptoms. Sci Rep 2021; 11:15598. [PMID: 34341363 PMCID: PMC8329289 DOI: 10.1038/s41598-021-93686-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/24/2021] [Indexed: 12/29/2022] Open
Abstract
Although some neurodegenerative diseases can be identified by behavioral characteristics relatively late in disease progression, we currently lack methods to predict who has developed disease before the onset of symptoms, when onset will occur, or the outcome of therapeutics. New biomarkers are needed. Here we describe spectral phenotyping, a new kind of biomarker that makes disease predictions based on chemical rather than biological endpoints in cells. Spectral phenotyping uses Fourier Transform Infrared (FTIR) spectromicroscopy to produce an absorbance signature as a rapid physiological indicator of disease state. FTIR spectromicroscopy has over the past been used in differential diagnoses of manifest disease. Here, we report that the unique FTIR chemical signature accurately predicts disease class in mouse with high probability in the absence of brain pathology. In human cells, the FTIR biomarker accurately predicts neurodegenerative disease class using fibroblasts as surrogate cells.
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Affiliation(s)
- Lila Lovergne
- Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Dhruba Ghosh
- Department of Statistics, University of California, Berkeley, CA, 94720, USA
| | - Renaud Schuck
- Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Aris A Polyzos
- Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andrew D Chen
- Department of Statistics, University of California, Berkeley, CA, 94720, USA
| | - Michael C Martin
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Edward S Barnard
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - James B Brown
- Department of Statistics, University of California, Berkeley, CA, 94720, USA
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Cynthia T McMurray
- Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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50
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Poggi L, Emmenegger L, Descorps-Declère S, Dumas B, Richard GF. Differential efficacies of Cas nucleases on microsatellites involved in human disorders and associated off-target mutations. Nucleic Acids Res 2021; 49:8120-8134. [PMID: 34233005 PMCID: PMC8373144 DOI: 10.1093/nar/gkab569] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/11/2021] [Accepted: 07/06/2021] [Indexed: 11/13/2022] Open
Abstract
Microsatellite expansions are the cause of >20 neurological or developmental human disorders. Shortening expanded repeats using specific DNA endonucleases may be envisioned as a gene editing approach. Here, we measured the efficacy of several CRISPR-Cas nucleases to induce recombination within disease-related microsatellites, in Saccharomyces cerevisiae. Broad variations in nuclease performances were detected on all repeat tracts. Wild-type Streptococcus pyogenes Cas9 (SpCas9) was more efficient than Staphylococcus aureus Cas9 on all repeats tested, except (CAG)33. Cas12a (Cpf1) was the most efficient on GAA trinucleotide repeats, whereas GC-rich repeats were more efficiently cut by SpCas9. The main genetic factor underlying Cas efficacy was the propensity of the recognition part of the sgRNA to form a stable secondary structure, independently of its structural part. This suggests that such structures form in vivo and interfere with sgRNA metabolism. The yeast genome contains 221 natural CAG/CTG and GAA/CTT trinucleotide repeats. Deep sequencing after nuclease induction identified three of them as carrying statistically significant low frequency mutations, corresponding to SpCas9 off-target double-strand breaks.
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Affiliation(s)
- Lucie Poggi
- Institut Pasteur, CNRS, UMR3525, 25 rue du Dr Roux, F-75015 Paris, France.,Sorbonne Université, Collège Doctoral, 4 Place Jussieu, F-75005 Paris, France.,Biologics Research, Sanofi R&D, 13 Quai Jules Guesde, 94403 Vitry sur Seine, France
| | - Lisa Emmenegger
- Institut Pasteur, CNRS, UMR3525, 25 rue du Dr Roux, F-75015 Paris, France
| | - Stéphane Descorps-Declère
- Institut Pasteur, CNRS, UMR3525, 25 rue du Dr Roux, F-75015 Paris, France.,Institut Pasteur, Bioinformatics and Biostatistics Hub, Department of Computational Biology, USR3756 CNRS, F-75015 Paris, France
| | - Bruno Dumas
- Biologics Research, Sanofi R&D, 13 Quai Jules Guesde, 94403 Vitry sur Seine, France
| | - Guy-Franck Richard
- Institut Pasteur, CNRS, UMR3525, 25 rue du Dr Roux, F-75015 Paris, France.,Sorbonne Université, Collège Doctoral, 4 Place Jussieu, F-75005 Paris, France
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