1
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Non-B DNA conformations analysis through molecular dynamics simulations. Biochim Biophys Acta Gen Subj 2022; 1866:130252. [DOI: 10.1016/j.bbagen.2022.130252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 03/13/2023]
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2
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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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3
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Hijazi H, Coelho FS, Gonzaga-Jauregui C, Bernardini L, Mar SS, Manning MA, Hanson-Kahn A, Naidu S, Srivastava S, Lee JA, Jones JR, Friez MJ, Alberico T, Torres B, Fang P, Cheung SW, Song X, Davis-Williams A, Jornlin C, Wight PA, Patyal P, Taube J, Poretti A, Inoue K, Zhang F, Pehlivan D, Carvalho CMB, Hobson GM, Lupski JR. Xq22 deletions and correlation with distinct neurological disease traits in females: Further evidence for a contiguous gene syndrome. Hum Mutat 2019; 41:150-168. [PMID: 31448840 DOI: 10.1002/humu.23902] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/14/2019] [Accepted: 08/22/2019] [Indexed: 01/24/2023]
Abstract
Xq22 deletions that encompass PLP1 (Xq22-PLP1-DEL) are notable for variable expressivity of neurological disease traits in females ranging from a mild late-onset form of spastic paraplegia type 2 (MIM# 312920), sometimes associated with skewed X-inactivation, to an early-onset neurological disease trait (EONDT) of severe developmental delay, intellectual disability, and behavioral abnormalities. Size and gene content of Xq22-PLP1-DEL vary and were proposed as potential molecular etiologies underlying variable expressivity in carrier females where two smallest regions of overlap (SROs) were suggested to influence disease. We ascertained a cohort of eight unrelated patients harboring Xq22-PLP1-DEL and performed high-density array comparative genomic hybridization and breakpoint-junction sequencing. Molecular characterization of Xq22-PLP1-DEL from 17 cases (eight herein and nine published) revealed an overrepresentation of breakpoints that reside within repeats (11/17, ~65%) and the clustering of ~47% of proximal breakpoints in a genomic instability hotspot with characteristic non-B DNA density. These findings implicate a potential role for genomic architecture in stimulating the formation of Xq22-PLP1-DEL. The correlation of Xq22-PLP1-DEL gene content with neurological disease trait in female cases enabled refinement of the associated SROs to a single genomic interval containing six genes. Our data support the hypothesis that genes contiguous to PLP1 contribute to EONDT.
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Affiliation(s)
- Hadia Hijazi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Fernanda S Coelho
- Programa de Pós-Graduação em Genética Departmento de Biologia Geral, UFMG, Belo Horizonte, Minas Gerais, Brazil.,Instituto René Rachou, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | | | - Laura Bernardini
- Medical Genetics Division, IRCCS "Casa Sollievo della Sofferenza" Foundation, San Giovanni Rotondo (FG), Italy
| | - Soe S Mar
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Melanie A Manning
- Division of Medical Genetics, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California.,Department of Pathology, Stanford University School of Medicine, Palo Alto, California
| | - Andrea Hanson-Kahn
- Division of Medical Genetics, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California.,Department of Genetics, Stanford University School of Medicine, Palo Alto, California
| | - SakkuBai Naidu
- Departments of Neurology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, Maryland
| | | | - Jennifer A Lee
- Molecular Diagnostic Laboratory, Greenwood Genetic Center, Greenwood, South Carolina
| | - Julie R Jones
- Molecular Diagnostic Laboratory, Greenwood Genetic Center, Greenwood, South Carolina
| | - Michael J Friez
- Molecular Diagnostic Laboratory, Greenwood Genetic Center, Greenwood, South Carolina
| | - Thomas Alberico
- Nemours Biomedical Research, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Barbara Torres
- Medical Genetics Division, IRCCS "Casa Sollievo della Sofferenza" Foundation, San Giovanni Rotondo (FG), Italy
| | - Ping Fang
- Clinical Genomics, WuXi NextCODE, Cambridge, Massachusetts
| | - Sau Wai Cheung
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Xiaofei Song
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Angelique Davis-Williams
- Nemours Biomedical Research, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Carly Jornlin
- Nemours Biomedical Research, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Patricia A Wight
- Department of Physiology and Biophysics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Pankaj Patyal
- Department of Physiology and Biophysics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Jennifer Taube
- Nemours Biomedical Research, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Andrea Poretti
- Departments of Neurology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ken Inoue
- Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Japan
| | - Feng Zhang
- State Key Laboratory of Genetic Engineering at School of Life Sciences, Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Section of Neurology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Grace M Hobson
- Nemours Biomedical Research, Nemours/Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas.,Texas Children's Hospital, Houston, Texas
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4
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Abstract
Supercoiling is a fundamental property of DNA, generated by polymerases and other DNA-binding proteins as a consequence of separating/bending the DNA double helix. DNA supercoiling plays a key role in gene expression and genome organization, but has proved difficult to study in eukaryotes because of the large, complex and chromatinized genomes. Key approaches to study DNA supercoiling in eukaryotes are (1) centrifugation-based or electrophoresis-based techniques in which supercoiled plasmids extracted from eukaryotic cells form a compacted writhed structure that migrates at a rate proportional to the level of DNA supercoiling; (2) in vivo approaches based on the preferential intercalation of psoralen molecules into under-wound DNA. Here, we outline the principles behind these techniques and discuss key discoveries, which have confirmed the presence and functional potential of unconstrained DNA supercoiling in eukaryotic genomes.
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5
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Bergquist H, Rocha CSJ, Álvarez-Asencio R, Nguyen CH, Rutland MW, Smith CIE, Good L, Nielsen PE, Zain R. Disruption of Higher Order DNA Structures in Friedreich's Ataxia (GAA)n Repeats by PNA or LNA Targeting. PLoS One 2016; 11:e0165788. [PMID: 27846236 PMCID: PMC5112992 DOI: 10.1371/journal.pone.0165788] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/07/2016] [Indexed: 01/08/2023] Open
Abstract
Expansion of (GAA)n repeats in the first intron of the Frataxin gene is associated with reduced mRNA and protein levels and the development of Friedreich’s ataxia. (GAA)n expansions form non-canonical structures, including intramolecular triplex (H-DNA), and R-loops and are associated with epigenetic modifications. With the aim of interfering with higher order H-DNA (like) DNA structures within pathological (GAA)n expansions, we examined sequence-specific interaction of peptide nucleic acid (PNA) with (GAA)n repeats of different lengths (short: n=9, medium: n=75 or long: n=115) by chemical probing of triple helical and single stranded regions. We found that a triplex structure (H-DNA) forms at GAA repeats of different lengths; however, single stranded regions were not detected within the medium size pathological repeat, suggesting the presence of a more complex structure. Furthermore, (GAA)4-PNA binding of the repeat abolished all detectable triplex DNA structures, whereas (CTT)5-PNA did not. We present evidence that (GAA)4-PNA can invade the DNA at the repeat region by binding the DNA CTT strand, thereby preventing non-canonical-DNA formation, and that triplex invasion complexes by (CTT)5-PNA form at the GAA repeats. Locked nucleic acid (LNA) oligonucleotides also inhibited triplex formation at GAA repeat expansions, and atomic force microscopy analysis showed significant relaxation of plasmid morphology in the presence of GAA-LNA. Thus, by inhibiting disease related higher order DNA structures in the Frataxin gene, such PNA and LNA oligomers may have potential for discovery of drugs aiming at recovering Frataxin expression.
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Affiliation(s)
- Helen Bergquist
- Department of Medical Biochemistry and Microbiology, Microbiology-Immunology, Uppsala University, Uppsala, Sweden
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Sweden
| | - Cristina S. J. Rocha
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Sweden
| | - Rubén Álvarez-Asencio
- KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Stockholm, Sweden
| | - Chi-Hung Nguyen
- Laboratoire de Pharmacochimie, Institut Curie, PSL Research University, UMR 9187 – U 1196 CNRS-Institut Curie, INSERM, Centre Universitaire, Orsay, France
| | - Mark. W. Rutland
- KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Stockholm, Sweden
| | - C. I. Edvard Smith
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Sweden
| | - Liam Good
- Department of Pathology and Infectious Diseases, Royal Veterinary College, University of London, United Kingdom
| | - Peter E. Nielsen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, The Panum Institute, Copenhagen, Denmark
| | - Rula Zain
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86, Huddinge, Sweden
- Department of Clinical Genetics, Centre for Rare Diseases, Karolinska University Hospital, SE-171 76, Stockholm, Sweden
- * E-mail:
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6
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Chromatin remodeller SMARCA4 recruits topoisomerase 1 and suppresses transcription-associated genomic instability. Nat Commun 2016; 7:10549. [PMID: 26842758 PMCID: PMC4742980 DOI: 10.1038/ncomms10549] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/25/2015] [Indexed: 02/07/2023] Open
Abstract
Topoisomerase 1, an enzyme that relieves superhelical tension, is implicated in transcription-associated mutagenesis and genome instability-associated with neurodegenerative diseases as well as activation-induced cytidine deaminase. From proteomic analysis of TOP1-associated proteins, we identify SMARCA4, an ATP-dependent chromatin remodeller; FACT, a histone chaperone; and H3K4me3, a transcriptionally active chromatin marker. Here we show that SMARCA4 knockdown in a B-cell line decreases TOP1 recruitment to chromatin, and leads to increases in Igh/c-Myc chromosomal translocations, variable and switch region mutations and negative superhelicity, all of which are also observed in response to TOP1 knockdown. In contrast, FACT knockdown inhibits association of TOP1 with H3K4me3, and severely reduces DNA cleavage and Igh/c-Myc translocations, without significant effect on TOP1 recruitment to chromatin. We thus propose that SMARCA4 is involved in the TOP1 recruitment to general chromatin, whereas FACT is required for TOP1 binding to H3K4me3 at non-B DNA containing chromatin for the site-specific cleavage. Topoisomerase 1 (TOP1) relieves superhelical tension when DNA strands are unwound during transcription. Here, Husain et al. report that SMARCA4, an ATP-dependent chromatin remodeller, is associated with TOP1 and suppresses transcription-associated genomic instability.
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7
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Völker J, Plum GE, Gindikin V, Klump HH, Breslauer KJ. Impact of bulge loop size on DNA triplet repeat domains: Implications for DNA repair and expansion. Biopolymers 2014; 101:1-12. [PMID: 23494673 PMCID: PMC3920904 DOI: 10.1002/bip.22236] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 03/05/2013] [Indexed: 11/12/2022]
Abstract
Repetitive DNA sequences exhibit complex structural and energy landscapes, populated by metastable, noncanonical states, that favor expansion and deletion events correlated with disease phenotypes. To probe the origins of such genotype-phenotype linkages, we report the impact of sequence and repeat number on properties of (CNG) repeat bulge loops. We find the stability of duplexes with a repeat bulge loop is controlled by two opposing effects; a loop junction-dependent destabilization of the underlying double helix, and a self-structure dependent stabilization of the repeat bulge loop. For small bulge loops, destabilization of the underlying double helix overwhelms any favorable contribution from loop self-structure. As bulge loop size increases, the stabilizing loop structure contribution dominates. The role of sequence on repeat loop stability can be understood in terms of its impact on the opposing influences of junction formation and loop structure. The nature of the bulge loop affects the thermodynamics of these two contributions differently, resulting in unique differences in repeat size-dependent minima in the overall enthalpy, entropy, and free energy changes. Our results define factors that control repeat bulge loop formation; knowledge required to understand how this helix imperfection is linked to DNA expansion, deletion, and disease phenotypes.
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Affiliation(s)
- Jens Völker
- Department of Chemistry and Chemical Biology, Rutgers, The
State University of New Jersey, 610 Taylor Rd, Piscataway, NJ 08854
| | - G. Eric Plum
- IBET, Inc., 1507 Chambers Road, Suite 301, Columbus, OH
43212
| | - Vera Gindikin
- Department of Chemistry and Chemical Biology, Rutgers, The
State University of New Jersey, 610 Taylor Rd, Piscataway, NJ 08854
| | - Horst H. Klump
- Department of Molecular and Cell Biology,
University of Cape Town, Private Bag, Rondebosch 7800, South Africa
| | - Kenneth J. Breslauer
- Department of Chemistry and Chemical Biology, Rutgers, The
State University of New Jersey, 610 Taylor Rd, Piscataway, NJ 08854
- The Cancer Institute of New Jersey, New Brunswick,
NJ 08901
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8
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Polak U, McIvor E, Dent SY, Wells RD, Napierala M. Expanded complexity of unstable repeat diseases. Biofactors 2013; 39:164-75. [PMID: 23233240 PMCID: PMC4648362 DOI: 10.1002/biof.1060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 09/19/2012] [Indexed: 11/05/2022]
Abstract
Unstable repeat diseases (URDs) share a common mutational phenomenon of changes in the copy number of short, tandemly repeated DNA sequences. More than 20 human neurological diseases are caused by instability, predominantly, expansion of microsatellite sequences. Changes in the repeat size initiate a cascade of pathological processes, frequently characteristic of a unique disease or a small subgroup of the URDs. Understanding of both the mechanism of repeat instability and molecular consequences of the repeat expansions is critical to developing successful therapies for these diseases. Recent technological breakthroughs in whole genome, transcriptome and proteome analyses will almost certainly lead to new discoveries regarding the mechanisms of repeat instability, the pathogenesis of URDs, and will facilitate development of novel therapeutic approaches. The aim of this review is to give a general overview of unstable repeats diseases, highlight the complexities of these diseases, and feature the emerging discoveries in the field.
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Affiliation(s)
- Urszula Polak
- University of Texas MD Anderson Cancer Center, Department of Molecular Carcinogenesis, Center for Cancer Epigenetics, Science Park, Smithville, Texas 78957, USA
- Poznan University of Medical Sciences, Department of Cell Biology, Rokietnicka 5D, 60-806 Poznan, Poland
| | - Elizabeth McIvor
- University of Texas MD Anderson Cancer Center, Department of Molecular Carcinogenesis, Center for Cancer Epigenetics, Science Park, Smithville, Texas 78957, USA
| | - Sharon Y.R. Dent
- University of Texas MD Anderson Cancer Center, Department of Molecular Carcinogenesis, Center for Cancer Epigenetics, Science Park, Smithville, Texas 78957, USA
| | - Robert D. Wells
- Institute of Biosciences and Technology, assing the University Health Science Center, Center for Genome Research, 2121 West Holcombe Boulevard, Houston, TX 77030, USA
| | - Marek Napierala
- University of Texas MD Anderson Cancer Center, Department of Molecular Carcinogenesis, Center for Cancer Epigenetics, Science Park, Smithville, Texas 78957, USA
- Correspondence should be addressed to: Dr. Marek Napierala, University of Texas MD Anderson Cancer Center, Department of Molecular Carcinogenesis, SRD 1.134, 1808 Park Road 1C, Smithville, TX 78957, tel. 512-237-6690,
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9
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Wojcik EA, Brzostek A, Bacolla A, Mackiewicz P, Vasquez KM, Korycka-Machala M, Jaworski A, Dziadek J. Direct and inverted repeats elicit genetic instability by both exploiting and eluding DNA double-strand break repair systems in mycobacteria. PLoS One 2012; 7:e51064. [PMID: 23251422 PMCID: PMC3519483 DOI: 10.1371/journal.pone.0051064] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 10/29/2012] [Indexed: 12/02/2022] Open
Abstract
Repetitive DNA sequences with the potential to form alternative DNA conformations, such as slipped structures and cruciforms, can induce genetic instability by promoting replication errors and by serving as a substrate for DNA repair proteins, which may lead to DNA double-strand breaks (DSBs). However, the contribution of each of the DSB repair pathways, homologous recombination (HR), non-homologous end-joining (NHEJ) and single-strand annealing (SSA), to this sort of genetic instability is not fully understood. Herein, we assessed the genome-wide distribution of repetitive DNA sequences in the Mycobacterium smegmatis, Mycobacterium tuberculosis and Escherichia coli genomes, and determined the types and frequencies of genetic instability induced by direct and inverted repeats, both in the presence and in the absence of HR, NHEJ, and SSA. All three genomes are strongly enriched in direct repeats and modestly enriched in inverted repeats. When using chromosomally integrated constructs in M. smegmatis, direct repeats induced the perfect deletion of their intervening sequences ~1,000-fold above background. Absence of HR further enhanced these perfect deletions, whereas absence of NHEJ or SSA had no influence, suggesting compromised replication fidelity. In contrast, inverted repeats induced perfect deletions only in the absence of SSA. Both direct and inverted repeats stimulated excision of the constructs from the attB integration sites independently of HR, NHEJ, or SSA. With episomal constructs, direct and inverted repeats triggered DNA instability by activating nucleolytic activity, and absence of the DSB repair pathways (in the order NHEJ>HR>SSA) exacerbated this instability. Thus, direct and inverted repeats may elicit genetic instability in mycobacteria by 1) directly interfering with replication fidelity, 2) stimulating the three main DSB repair pathways, and 3) enticing L5 site-specific recombination.
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Affiliation(s)
- Ewelina A. Wojcik
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
- Department of Genetics of Microorganisms, Institute of Microbiology and Immunology, University of Lodz, Lodz, Poland
| | - Anna Brzostek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Albino Bacolla
- The University of Texas at Austin, Division of Pharmacology and Toxicology, Dell Pediatric Research Institute, Austin, Texas, United States of America
| | - Pawel Mackiewicz
- Department of Genomics, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Karen M. Vasquez
- The University of Texas at Austin, Division of Pharmacology and Toxicology, Dell Pediatric Research Institute, Austin, Texas, United States of America
| | | | - Adam Jaworski
- Department of Genetics of Microorganisms, Institute of Microbiology and Immunology, University of Lodz, Lodz, Poland
| | - Jaroslaw Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
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10
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Tang W, Dominska M, Gawel M, Greenwell PW, Petes TD. Genomic deletions and point mutations induced in Saccharomyces cerevisiae by the trinucleotide repeats (GAA·TTC) associated with Friedreich's ataxia. DNA Repair (Amst) 2012. [PMID: 23182423 DOI: 10.1016/j.dnarep.2012.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Expansion of certain trinucleotide repeats causes several types of human diseases, and such tracts are associated with the formation of deletions and other types of genetic rearrangements in Escherichia coli, yeast, and mammalian cells. Below, we show that long (230 repeats) tracts of the trinucleotide associated with Friedreich's ataxia (GAA·TTC) stimulate both large (>50 bp) deletions and point mutations in a reporter gene located more than 1 kb from the repetitive tract. Sequence analysis of deletion breakpoints indicates that the deletions reflect non-homologous end joining of double-stranded DNA breaks (DSBs) initiated in the tract. The tract-induced point mutations appear to reflect a different mechanism involving single-strand annealing of DNA molecules generated by DSBs within the tract, followed by filling-in of single-stranded gaps by the error-prone DNA polymerase zeta.
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Affiliation(s)
- Wei Tang
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC 27710, USA
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11
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Begum NA, Honjo T. Evolutionary comparison of the mechanism of DNA cleavage with respect to immune diversity and genomic instability. Biochemistry 2012; 51:5243-56. [PMID: 22712724 DOI: 10.1021/bi3005895] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is generally assumed that the genetic mechanism for immune diversity is unique and distinct from that for general genome diversity, in part because of the high efficiency and strict regulation of immune diversity. This expectation was partially met by the discovery of RAG1 and -2, which catalyze V(D)J recombination to generate the immune repertoire of B and T lymphocyte receptors. RAG1 and -2 were later shown to be derived from a transposon. On the other hand, activation-induced cytidine deaminase (AID), which mediates both somatic hypermutation (SHM) and the class-switch recombination (CSR) of the immunoglobulin genes, evolved earlier than RAG1 and -2 in jawless vertebrates. This review compares immune diversity and general genome diversity from an evolutionary perspective, shedding light on the roles of DNA-cleaving enzymes and target recognition markers. This comparison revealed that AID-mediated SHM and CSR share the cleaving enzyme topoisomerase 1 with transcription-associated mutation (TAM) and triplet contraction, which is involved in many genetic diseases. These genome-altering events appear to target DNA with non-B structure, which is induced by the inefficient correction of the excessive supercoiling that is caused by active transcription. Furthermore, an epigenetic modification on chromatin (histone H3K4 trimethylation) is used as a mark for DNA cleavage sites in meiotic recombination, V(D)J recombination, CSR, and SHM. We conclude that acquired immune diversity evolved via the appearance of an AID orthologue that utilized a preexisting mechanism for genomic instability, such as TAM.
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Affiliation(s)
- Nasim A Begum
- Department of Immunology and Genomic Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
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12
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Abstract
A vast literature has explored the genetic interactions among the cellular components regulating gene expression in many organisms. Early on, in the absence of any biochemical definition, regulatory modules were conceived using the strict formalism of genetics to designate the modifiers of phenotype as either cis- or trans-acting depending on whether the relevant genes were embedded in the same or separate DNA molecules. This formalism distilled gene regulation down to its essence in much the same way that consideration of an ideal gas reveals essential thermodynamic and kinetic principles. Yet just as the anomalous behavior of materials may thwart an engineer who ignores their non-ideal properties, schemes to control and manipulate the genetic and epigenetic programs of cells may falter without a fuller and more quantitative elucidation of the physical and chemical characteristics of DNA and chromatin in vivo.
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Affiliation(s)
- David Levens
- Laboratory of Pathology, National Cancer Institute, 10 Center Drive, Building 10, Room 2N106, Bethesda, MD 20892-1500, USA.
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13
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Bacolla A, Wang G, Jain A, Chuzhanova NA, Cer RZ, Collins JR, Cooper DN, Bohr VA, Vasquez KM. Non-B DNA-forming sequences and WRN deficiency independently increase the frequency of base substitution in human cells. J Biol Chem 2011; 286:10017-26. [PMID: 21285356 PMCID: PMC3060453 DOI: 10.1074/jbc.m110.176636] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 01/31/2011] [Indexed: 01/01/2023] Open
Abstract
Although alternative DNA secondary structures (non-B DNA) can induce genomic rearrangements, their associated mutational spectra remain largely unknown. The helicase activity of WRN, which is absent in the human progeroid Werner syndrome, is thought to counteract this genomic instability. We determined non-B DNA-induced mutation frequencies and spectra in human U2OS osteosarcoma cells and assessed the role of WRN in isogenic knockdown (WRN-KD) cells using a supF gene mutation reporter system flanked by triplex- or Z-DNA-forming sequences. Although both non-B DNA and WRN-KD served to increase the mutation frequency, the increase afforded by WRN-KD was independent of DNA structure despite the fact that purified WRN helicase was found to resolve these structures in vitro. In U2OS cells, ∼70% of mutations comprised single-base substitutions, mostly at G·C base-pairs, with the remaining ∼30% being microdeletions. The number of mutations at G·C base-pairs in the context of NGNN/NNCN sequences correlated well with predicted free energies of base stacking and ionization potentials, suggesting a possible origin via oxidation reactions involving electron loss and subsequent electron transfer (hole migration) between neighboring bases. A set of ∼40,000 somatic mutations at G·C base pairs identified in a lung cancer genome exhibited similar correlations, implying that hole migration may also be involved. We conclude that alternative DNA conformations, WRN deficiency and lung tumorigenesis may all serve to increase the mutation rate by promoting, through diverse pathways, oxidation reactions that perturb the electron orbitals of neighboring bases. It follows that such "hole migration" is likely to play a much more widespread role in mutagenesis than previously anticipated.
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Affiliation(s)
- Albino Bacolla
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
| | - Guliang Wang
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
| | - Aklank Jain
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
| | - Nadia A. Chuzhanova
- the School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, United Kingdom
| | - Regina Z. Cer
- the Advanced Biomedical Computing Center, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702
| | - Jack R. Collins
- the Advanced Biomedical Computing Center, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702
| | - David N. Cooper
- the Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, CF14 4XN, United Kingdom, and
| | - Vilhelm A. Bohr
- the Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224
| | - Karen M. Vasquez
- From the Department of Molecular Carcinogenesis, Science Park-Research Division, The University of Texas, M. D. Anderson Cancer Center, Smithville, Texas 78957
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14
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Bergquist H, Nikravesh A, Fernández RD, Larsson V, Nguyen CH, Good L, Zain R. Structure-specific recognition of Friedreich's ataxia (GAA)n repeats by benzoquinoquinoxaline derivatives. Chembiochem 2010; 10:2629-37. [PMID: 19746387 DOI: 10.1002/cbic.200900263] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Expansion of GAA triplet repeats in intron 1 of the FXN gene reduces frataxin expression and causes Friedreich's ataxia. (GAA)n repeats form non-B-DNA structures, including triple helix H-DNA and higher-order structures (sticky DNA). In the proposed mechanisms of frataxin gene silencing, central unanswered questions involve the characterization of non-B-DNA structure(s) that are strongly suggested to play a role in frataxin expression. Here we examined (GAA)n binding by triplex-stabilizing benzoquinoquinoxaline (BQQ) and the corresponding triplex-DNA-cleaving BQQ-1,10-phenanthroline (BQQ-OP) compounds. We also examined the ability of these compounds to act as structural probes for H-DNA formation within higher-order structures at pathological frataxin sequences in plasmids. DNA-complex-formation analyses with a gel-mobility-shift assay and sequence-specific probing of H-DNA-forming (GAA)n sequences by single-strand oligonucleotides and triplex-directed cleavage demonstrated that a parallel pyrimidine (rather than purine) triplex is the more stable motif formed at (GAA)n repeats under physiologically relevant conditions.
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Affiliation(s)
- Helen Bergquist
- Department of Molecular Biology and Functional Genomics, Stockholm University, Svante Arrhenius väg 20C, 10691 Stockholm, Sweden
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15
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Wang G, Zhao J, Vasquez KM. Methods to determine DNA structural alterations and genetic instability. Methods 2009; 48:54-62. [PMID: 19245837 PMCID: PMC2693251 DOI: 10.1016/j.ymeth.2009.02.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Accepted: 02/15/2009] [Indexed: 11/16/2022] Open
Abstract
Chromosomal DNA is a dynamic structure that can adopt a variety of non-canonical (i.e., non-B) conformations. In this regard, at least 10 different forms of non-B DNA conformations have been identified; many of them have been found to be mutagenic, and associated with human disease development. Despite the importance of non-B DNA structures in genetic instability and DNA metabolic processes, mechanisms by which instability occurs remain largely undefined. The purpose of this review is to summarize current methodologies that are used to address questions in the field of non-B DNA structure-induced genetic instability. Advantages and disadvantages of each method will be discussed. A focused effort to further elucidate the mechanisms of non-B DNA-induced genetic instability will lead to a better understanding of how these structure-forming sequences contribute to the development of human disease.
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Affiliation(s)
- Guliang Wang
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, 1808 Park Road 1-C, Smithville, TX 78957
| | - Junhua Zhao
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, 1808 Park Road 1-C, Smithville, TX 78957
| | - Karen M. Vasquez
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, 1808 Park Road 1-C, Smithville, TX 78957
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16
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Bacolla A, Wells RD. Non-B DNA conformations as determinants of mutagenesis and human disease. Mol Carcinog 2009; 48:273-85. [PMID: 19306308 DOI: 10.1002/mc.20507] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Repetitive DNA motifs may fold into non-B DNA structures, including cruciforms/hairpins, triplexes, slipped conformations, quadruplexes, and left-handed Z-DNA, thereby representing chromosomal targets for DNA repair, recombination, and aberrant DNA synthesis leading to repeat expansion or genomic rearrangements associated with neurodegenerative and genomic disorders. Hairpins and quadruplexes also determined the relative abundances of simple sequence repeats (SSR) in vertebrate genomes, whereas strong base stacking has permitted the expansion of purine.pyrimidine-rich SSR during evolutionary time. SSR are enriched in regulatory and cancer-related gene classes, where they have been actively recruited to participate in both gene and protein functions. SSR polymorphic alleles in the population are associated with cancer susceptibility, including within genes that appear to share regulatory circuits involving reactive oxygen species.
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Affiliation(s)
- Albino Bacolla
- Center for Genome Research, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Texas Medical Center,2121 W. Holcombe Blvd.,Houston, TX 77030, USA
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17
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Abstract
The fragile X syndrome results from expansions as well as deletions of the repeating CGG.CCG DNA sequence in the 5'-untranslated region of the FMR1 gene on the X chromosome. The relative frequency of disease cases promoted by these two types of mutations cannot be ascertained at present because the routine clinical assay monitors only expansions. At least 30 articles have been reviewed that document the involvement of deletions of part or all of the CGG.CCG repeats along with varying extents of DNA flanking regions as well as very small mutations including single base pair changes. Studies of deletion mutants of CGG.CCG tracts in Escherichia coli plasmids revealed a similar spectrum of mutagenic products. The triplet repeat tract in a non-B conformation is the mutagen, not the sequence per se in the right-handed B helix. Hence, molecular investigations in a simple model organism may generate useful initial information toward therapeutic strategies for this disease.
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Affiliation(s)
- Robert D Wells
- Center for Genome Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas Medical Center, Houston, Texas 77030-3303, USA.
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18
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Wells RD. Discovery of the role of non-B DNA structures in mutagenesis and human genomic disorders. J Biol Chem 2008; 284:8997-9009. [PMID: 19054760 DOI: 10.1074/jbc.x800010200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Robert D Wells
- Center for Genome Research, Institute of Biosciences and Technology, Texas A&M System Health Science Center, The Texas Medical Center, Houston, Texas 77030-3303, USA.
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19
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Bacolla A, Larson JE, Collins JR, Li J, Milosavljevic A, Stenson PD, Cooper DN, Wells RD. Abundance and length of simple repeats in vertebrate genomes are determined by their structural properties. Genome Res 2008; 18:1545-53. [PMID: 18687880 DOI: 10.1101/gr.078303.108] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Microsatellites are abundant in vertebrate genomes, but their sequence representation and length distributions vary greatly within each family of repeats (e.g., tetranucleotides). Biophysical studies of 82 synthetic single-stranded oligonucleotides comprising all tetra- and trinucleotide repeats revealed an inverse correlation between the stability of folded-back hairpin and quadruplex structures and the sequence representation for repeats > or =30 bp in length in nine vertebrate genomes. Alternatively, the predicted energies of base-stacking interactions correlated directly with the longest length distributions in vertebrate genomes. Genome-wide analyses indicated that unstable sequences, such as CAG:CTG and CCG:CGG, were over-represented in coding regions and that micro/minisatellites were recruited in genes involved in transcription and signaling pathways, particularly in the nervous system. Microsatellite instability (MSI) is a hallmark of cancer, and length polymorphism within genes can confer susceptibility to inherited disease. Sequences that manifest the highest MSI values also displayed the strongest base-stacking interactions; analyses of 62 tri- and tetranucleotide repeat-containing genes associated with human genetic disease revealed enrichments similar to those noted for micro/minisatellite-containing genes. We conclude that DNA structure and base-stacking determined the number and length distributions of microsatellite repeats in vertebrate genomes over evolutionary time and that micro/minisatellites have been recruited to participate in both gene and protein function.
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Affiliation(s)
- Albino Bacolla
- Institute of Biosciences and Technology, Center for Genome Research, Texas A&M University Health Science Center, Houston, Texas 77030, USA.
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20
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Abstract
Friedreich ataxia, the most common inherited ataxia, is caused by the transcriptional silencing of the FXN gene, which codes for the 210 amino acid frataxin, a mitochondrial protein involved in iron-sulfur cluster biosynthesis. The expansion of the GAA x TTC tract in intron 1 to as many as 1700 repeats elicits the transcriptional silencing by the formation of non-B DNA structures (triplexes or sticky DNA), the formation of a persistent DNA x RNA hybrid, or heterochromatin formation. The triplex (sticky DNA) adopted by the long repeat sequence also elicits profound mutagenic, genetic instability, and recombination behaviors. Early stage therapeutic investigations involving polyamides or histone deacetylase inhibitors are being pursued. Friedreich ataxia may be one of the most thoroughly studied hereditary neurological disease from a pathophysiological standpoint.
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Affiliation(s)
- Robert D Wells
- Center for Genome Research, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, The Texas Medical Center, 2121 W. Holcombe Blvd., Houston, TX 77030-3303, USA.
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21
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Kosmider B, Wells RD. Fragile X repeats are potent inducers of complex, multiple site rearrangements in flanking sequences in Escherichia coli. DNA Repair (Amst) 2007; 6:1850-63. [PMID: 17851139 DOI: 10.1016/j.dnarep.2007.07.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 06/27/2007] [Accepted: 07/12/2007] [Indexed: 01/02/2023]
Abstract
(CGG.CCG)n repeats induce the formation of complex, multiple site rearrangements and/or gross deletions in flanking DNA sequences in Escherichia coli plasmids. DNA sequence analyses of mutant clones revealed the influence of (a) the length (24, 44 or 73 repeats), (b) the orientation of the CGG.CCG region relative to the unidirectional origin, and (c) its transcription status. Complex rearrangements had occurred in the mutant clones since some products contained deletions, inversions and insertions and some products had only gross deletions. Furthermore, the CGG.CCG repeats repeatedly induced, up to 22 times, the formation of identical (to the bp) mutagenic products indicating the powerful nature of the complex processes involved. Also, the mutations were bidirectional from the CGG.CCG tract. The healed junctions had CG-rich microhomologies of 1-6bp, CG-rich regions and putative cruciforms and slipped structures. Hence, the fragile X syndrome mutagenic spectrum has been found, at least in part, in our model system.
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Affiliation(s)
- Beata Kosmider
- Center for Genome Research, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Texas Medical Center, 2121 W. Holcombe Blvd., Houston, TX 77030-3303, USA
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22
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Wells RD. Non-B DNA conformations, mutagenesis and disease. Trends Biochem Sci 2007; 32:271-8. [PMID: 17493823 DOI: 10.1016/j.tibs.2007.04.003] [Citation(s) in RCA: 230] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 04/04/2007] [Accepted: 04/20/2007] [Indexed: 11/29/2022]
Abstract
Recent discoveries have revealed that simple repeating DNA sequences, which are known to adopt non-B DNA conformations (such as triplexes, cruciforms, slipped structures, left-handed Z-DNA and tetraplexes), are mutagenic. The mutagenesis is due to the non-B DNA conformation rather than to the DNA sequence per se in the orthodox right-handed Watson-Crick B-form. The human genetic consequences of these non-B structures are approximately 20 neurological diseases, approximately 50 genomic disorders (caused by gross deletions, inversions, duplications and translocations), and several psychiatric diseases involving polymorphisms in simple repeating sequences. Thus, the convergence of biochemical, genetic and genomic studies has demonstrated a new paradigm implicating the non-B DNA conformations as the mutagenesis specificity determinants, not the sequences as such.
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Affiliation(s)
- Robert D Wells
- Center for Genome Research, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Texas Medical Center, 2121 West Holcombe Boulevard, Houston, TX 77030-3303, USA.
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