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Beseiso D, Chen EV, McCarthy SE, Martin KN, Gallagher EP, Miao J, Yatsunyk L. OUP accepted manuscript. Nucleic Acids Res 2022; 50:2959-2972. [PMID: 35212369 PMCID: PMC8934647 DOI: 10.1093/nar/gkac091] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 01/26/2022] [Accepted: 01/28/2022] [Indexed: 11/13/2022] Open
Abstract
G-quadruplexes (GQs) are non-canonical DNA structures composed of stacks of stabilized G-tetrads. GQs play an important role in a variety of biological processes and may form at telomeres and oncogene promoters among other genomic locations. Here, we investigate nine variants of telomeric DNA from Tetrahymena thermophila with the repeat (TTGGGG)n. Biophysical data indicate that the sequences fold into stable four-tetrad GQs which adopt multiple conformations according to native PAGE. Excitingly, we solved the crystal structure of two variants, TET25 and TET26. The two variants differ by the presence of a 3′-T yet adopt different GQ conformations. TET25 forms a hybrid [3 + 1] GQ and exhibits a rare 5′-top snapback feature. Consequently, TET25 contains four loops: three lateral (TT, TT, and GTT) and one propeller (TT). TET26 folds into a parallel GQ with three TT propeller loops. To the best of our knowledge, TET25 and TET26 are the first reported hybrid and parallel four-tetrad unimolecular GQ structures. The results presented here expand the repertoire of available GQ structures and provide insight into the intricacy and plasticity of the 3D architecture adopted by telomeric repeats from T. thermophila and GQs in general.
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Affiliation(s)
- Dana Beseiso
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Erin V Chen
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Sawyer E McCarthy
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Kailey N Martin
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Elizabeth P Gallagher
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
| | - Joanne Miao
- Department of Chemistry and Biochemistry, Swarthmore College, 500 College Ave, Swarthmore, PA 19081, USA
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2
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Chatain J, Blond A, Phan AT, Saintomé C, Alberti P. GGGCTA repeats can fold into hairpins poorly unfolded by replication protein A: a possible origin of the length-dependent instability of GGGCTA variant repeats in human telomeres. Nucleic Acids Res 2021; 49:7588-7601. [PMID: 34214172 PMCID: PMC8287962 DOI: 10.1093/nar/gkab518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 06/01/2021] [Accepted: 06/30/2021] [Indexed: 11/19/2022] Open
Abstract
Human telomeres are composed of GGGTTA repeats and interspersed with variant repeats. The GGGCTA variant motif was identified in the proximal regions of human telomeres about 10 years ago and was shown to display a length-dependent instability. In parallel, a structural study showed that four GGGCTA repeats folded into a non-canonical G-quadruplex (G4) comprising a Watson-Crick GCGC tetrad. It was proposed that this non-canonical G4 might be an additional obstacle for telomere replication. In the present study, we demonstrate that longer GGGCTA arrays fold into G4 and into hairpins. We also demonstrate that replication protein A (RPA) efficiently binds to GGGCTA repeats structured into G4 but poorly binds to GGGCTA repeats structured into hairpins. Our results (along with results obtained with a more stable variant motif) suggest that GGGCTA hairpins are at the origin of GGGCTA length-dependent instability. They also suggest, as working hypothesis, that failure of efficient binding of RPA to GGGCTA structured into hairpins might be involved in the mechanism of GGGCTA array instability. On the basis of our present and past studies about telomeric G4 and their interaction with RPA, we propose an original point of view about telomeric G4 and the evolution of telomeric motifs.
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Affiliation(s)
- Jean Chatain
- Laboratoire Structure et Instabilité des Génomes (StrInG), Muséum national d’Histoire naturelle, CNRS, Inserm, Paris 75005, France
| | - Alain Blond
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), Muséum national d’Histoire naturelle, CNRS, Paris 75005, France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
| | - Carole Saintomé
- Laboratoire Structure et Instabilité des Génomes (StrInG), Muséum national d’Histoire naturelle, CNRS, Inserm, Paris 75005, France
- Sorbonne Université, UFR927, Paris 75005, France
| | - Patrizia Alberti
- Laboratoire Structure et Instabilité des Génomes (StrInG), Muséum national d’Histoire naturelle, CNRS, Inserm, Paris 75005, France
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3
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Bryan TM. G-Quadruplexes at Telomeres: Friend or Foe? Molecules 2020; 25:molecules25163686. [PMID: 32823549 PMCID: PMC7464828 DOI: 10.3390/molecules25163686] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 12/28/2022] Open
Abstract
Telomeres are DNA-protein complexes that cap and protect the ends of linear chromosomes. In almost all species, telomeric DNA has a G/C strand bias, and the short tandem repeats of the G-rich strand have the capacity to form into secondary structures in vitro, such as four-stranded G-quadruplexes. This has long prompted speculation that G-quadruplexes play a positive role in telomere biology, resulting in selection for G-rich tandem telomere repeats during evolution. There is some evidence that G-quadruplexes at telomeres may play a protective capping role, at least in yeast, and that they may positively affect telomere maintenance by either the enzyme telomerase or by recombination-based mechanisms. On the other hand, G-quadruplex formation in telomeric DNA, as elsewhere in the genome, can form an impediment to DNA replication and a source of genome instability. This review summarizes recent evidence for the in vivo existence of G-quadruplexes at telomeres, with a focus on human telomeres, and highlights some of the many unanswered questions regarding the location, form, and functions of these structures.
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Affiliation(s)
- Tracy M Bryan
- Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
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Shubernetskaya O, Skvortsov D, Evfratov S, Rubtsova M, Belova E, Strelkova O, Cherepaninets V, Zhironkina O, Olovnikov A, Zvereva M, Dontsova O, Kireev I. Interstitial telomeric repeats-associated DNA breaks. Nucleus 2017; 8:641-653. [PMID: 28914588 PMCID: PMC5788545 DOI: 10.1080/19491034.2017.1356501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 06/28/2017] [Accepted: 07/04/2017] [Indexed: 02/08/2023] Open
Abstract
During a cell's lifespan, DNA break formation is a common event, associated with many processes, from replication to apoptosis. Most of DNA breaks are readily repaired, but some are meant to persist in time, such as the chromosome ends, protected by telomeres. Besides them, eukaryotic genomes comprise shorter stretches of interstitial telomeric repeats. We assumed that the latter may also be associated with the formation of DNA breaks meant to persist in time. In zebrafish and mouse embryos, cells containing numerous breakage foci were identified. These breaks were not associated with apoptosis or replication, nor did they seem to activate DNA damage response machinery. Unlike short-living, accidental sparse breaks, the ones we found seem to be closely associated, forming discrete break foci. A PCR-based method was developed, allowing specific amplification of DNA regions located between inverted telomeric repeats associated with breaks. The cloning and sequencing of such DNA fragments were found to denote some specificity in their distribution for different tissue types and development stages.
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Affiliation(s)
- Olga Shubernetskaya
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Dmitry Skvortsov
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Sergey Evfratov
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Maria Rubtsova
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Elena Belova
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Olga Strelkova
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Varvara Cherepaninets
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Oxana Zhironkina
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | | | - Maria Zvereva
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Olga Dontsova
- Chemistry Department, M.V. Lomonosov Moscow State University, Moscow, Russia
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
- Skolkovo Institute of Science and Technology, Skolkovo, Moscow, Russia
| | - Igor Kireev
- A.N. Belozersky Institute of Physico-chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
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Parker MS, Sallee FR, Park EA, Parker SL. Homoiterons and expansion in ribosomal RNAs. FEBS Open Bio 2015; 5:864-76. [PMID: 26636029 PMCID: PMC4637361 DOI: 10.1016/j.fob.2015.10.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/30/2015] [Accepted: 10/14/2015] [Indexed: 11/27/2022] Open
Abstract
Homoiterons like GGGGGGG stabilize ribosomal RNAs of thermophile prokaryotes. In eukaryotes, homoiterons are much more abundant in RNA of the larger subunit (LSU). The LSU repeats increase with phylogenetic rank to 28% entire RNA sequence in hominids. In mammal LSU RNAs, these repeats constitute 45% of the massive expansion segments. These repeats may help in anchoring of ribosomes and export of secretory proteins.
Ribosomal RNAs in both prokaryotes and eukaryotes feature numerous repeats of three or more nucleotides with the same nucleobase (homoiterons). In prokaryotes these repeats are much more frequent in thermophile compared to mesophile or psychrophile species, and have similar frequency in both large RNAs. These features point to use of prokaryotic homoiterons in stabilization of both ribosomal subunits. The two large RNAs of eukaryotic cytoplasmic ribosomes have expanded to a different degree across the evolutionary ladder. The big RNA of the larger subunit (60S LSU) evolved expansion segments of up to 2400 nucleotides, and the smaller subunit (40S SSU) RNA acquired expansion segments of not more than 700 nucleotides. In the examined eukaryotes abundance of rRNA homoiterons generally follows size and nucleotide bias of the expansion segments, and increases with GC content and especially with phylogenetic rank. Both the nucleotide bias and frequency of homoiterons are much larger in metazoan and angiosperm LSU compared to the respective SSU RNAs. This is especially pronounced in the tetrapod vertebrates and seems to culminate in the hominid mammals. The stability of secondary structure in polyribonucleotides would significantly connect to GC content, and should also relate to G and C homoiteron content. RNA modeling points to considerable presence of homoiteron-rich double-stranded segments especially in vertebrate LSU RNAs, and homoiterons with four or more nucleotides in the vertebrate and angiosperm LSU RNAs are largely confined to the expansion segments. These features could mainly relate to protein export function and attachment of LSU to endoplasmic reticulum and other subcellular networks.
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Key Words
- ES, an expansion segment
- LSU, large cytoplasmic ribosome subunit (50S in prokaryotes and archaea, 60S in eukaryotes)
- PCN, homoionic motifs with ⩾3% and ⩾50% ionic residues, found especially in Polynucleotide-binding proteins, Carrier proteins and Nuclear localization signals
- RNA expansion segment
- RNA nucleotide bias
- RNA nucleotide repeat
- SSU, small cytoplasmic ribosome subunit (30S in prokaryotes and archaea, 40S in eukaryotes)
- XN or NX, [X = a number] a nucleotide unit with same nucleobases (homoiteron), such as 4U or U4 for UUUU
- aa, amino acid residues
- mRNP, messenger ribonucleoprotein
- ncRNA, non-coding RNA
- nt, nucleotides
- u, nucleotide unit
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Affiliation(s)
- Michael S Parker
- Department of Microbiology and Molecular Cell Sciences, University of Memphis, Memphis, TN 38152, USA
| | - Floyd R Sallee
- Department of Psychiatry, University of Cincinnati School of Medicine, Cincinnati, OH 45276, USA
| | - Edwards A Park
- Department of Pharmacology, University of Tennessee Health Sciences Center, Memphis, TN 38163, USA
| | - Steven L Parker
- Department of Pharmacology, University of Tennessee Health Sciences Center, Memphis, TN 38163, USA
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Lin J, Countryman P, Buncher N, Kaur P, E L, Zhang Y, Gibson G, You C, Watkins SC, Piehler J, Opresko PL, Kad NM, Wang H. TRF1 and TRF2 use different mechanisms to find telomeric DNA but share a novel mechanism to search for protein partners at telomeres. Nucleic Acids Res 2013; 42:2493-504. [PMID: 24271387 PMCID: PMC3936710 DOI: 10.1093/nar/gkt1132] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Human telomeres are maintained by the shelterin protein complex in which TRF1 and TRF2 bind directly to duplex telomeric DNA. How these proteins find telomeric sequences among a genome of billions of base pairs and how they find protein partners to form the shelterin complex remains uncertain. Using single-molecule fluorescence imaging of quantum dot-labeled TRF1 and TRF2, we study how these proteins locate TTAGGG repeats on DNA tightropes. By virtue of its basic domain TRF2 performs an extensive 1D search on nontelomeric DNA, whereas TRF1’s 1D search is limited. Unlike the stable and static associations observed for other proteins at specific binding sites, TRF proteins possess reduced binding stability marked by transient binding (∼9–17 s) and slow 1D diffusion on specific telomeric regions. These slow diffusion constants yield activation energy barriers to sliding ∼2.8–3.6 κBT greater than those for nontelomeric DNA. We propose that the TRF proteins use 1D sliding to find protein partners and assemble the shelterin complex, which in turn stabilizes the interaction with specific telomeric DNA. This ‘tag-team proofreading’ represents a more general mechanism to ensure a specific set of proteins interact with each other on long repetitive specific DNA sequences without requiring external energy sources.
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Affiliation(s)
- Jiangguo Lin
- Physics Department, North Carolina State University, Raleigh, NC 27695, USA, Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15219, USA, Electric and Computer Engineering Department, University of North Carolina at Charlotte, Charlotte, NC 28223, USA, Department of Industrial and System Engineering, North Carolina State University, Raleigh, NC 27695, USA, Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15219, USA, Division of Biophysics, Universität Osnabrück, Barbarstrasse 11, 49076, Osnabrück, Germany and School of Biological Sciences, University of Essex, Colchester, Essex CO4 3SQ UK
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7
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Lormand JD, Buncher N, Murphy CT, Kaur P, Lee MY, Burgers P, Wang H, Kunkel TA, Opresko PL. DNA polymerase δ stalls on telomeric lagging strand templates independently from G-quadruplex formation. Nucleic Acids Res 2013; 41:10323-33. [PMID: 24038470 PMCID: PMC3905856 DOI: 10.1093/nar/gkt813] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Previous evidence indicates that telomeres resemble common fragile sites and present a challenge for DNA replication. The precise impediments to replication fork progression at telomeric TTAGGG repeats are unknown, but are proposed to include G-quadruplexes (G4) on the G-rich strand. Here we examined DNA synthesis and progression by the replicative DNA polymerase δ/proliferating cell nuclear antigen/replication factor C complex on telomeric templates that mimic the leading C-rich and lagging G-rich strands. Increased polymerase stalling occurred on the G-rich template, compared with the C-rich and nontelomeric templates. Suppression of G4 formation by substituting Li+ for K+ as the cation, or by using templates with 7-deaza-G residues, did not alleviate Pol δ pause sites within the G residues. Furthermore, we provide evidence that G4 folding is less stable on single-stranded circular TTAGGG templates where ends are constrained, compared with linear oligonucleotides. Artificially stabilizing G4 structures on the circular templates with the G4 ligand BRACO-19 inhibited Pol δ progression into the G-rich repeats. Similar results were obtained for yeast and human Pol δ complexes. Our data indicate that G4 formation is not required for polymerase stalling on telomeric lagging strands and suggest that an alternative mechanism, in addition to stable G4s, contributes to replication stalling at telomeres.
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Affiliation(s)
- Justin D Lormand
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, 100 Technology Drive, Pittsburgh, PA 15219, USA, Department of Physics, North Carolina State University, 2401 Stinson Drive, Raleigh, NC, 27695, USA, Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA, Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA and Laboratory of Molecular Genetics and Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, DHHS, Research Triangle Park, NC 27709, USA
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8
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König SLB, Huppert JL, Sigel RKO, Evans AC. Distance-dependent duplex DNA destabilization proximal to G-quadruplex/i-motif sequences. Nucleic Acids Res 2013; 41:7453-61. [PMID: 23771141 PMCID: PMC3753619 DOI: 10.1093/nar/gkt476] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 05/04/2013] [Accepted: 05/08/2013] [Indexed: 01/29/2023] Open
Abstract
G-quadruplexes and i-motifs are complementary examples of non-canonical nucleic acid substructure conformations. G-quadruplex thermodynamic stability has been extensively studied for a variety of base sequences, but the degree of duplex destabilization that adjacent quadruplex structure formation can cause has yet to be fully addressed. Stable in vivo formation of these alternative nucleic acid structures is likely to be highly dependent on whether sufficient spacing exists between neighbouring duplex- and quadruplex-/i-motif-forming regions to accommodate quadruplexes or i-motifs without disrupting duplex stability. Prediction of putative G-quadruplex-forming regions is likely to be assisted by further understanding of what distance (number of base pairs) is required for duplexes to remain stable as quadruplexes or i-motifs form. Using oligonucleotide constructs derived from precedented G-quadruplexes and i-motif-forming bcl-2 P1 promoter region, initial biophysical stability studies indicate that the formation of G-quadruplex and i-motif conformations do destabilize proximal duplex regions. The undermining effect that quadruplex formation can have on duplex stability is mitigated with increased distance from the duplex region: a spacing of five base pairs or more is sufficient to maintain duplex stability proximal to predicted quadruplex/i-motif-forming regions.
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Affiliation(s)
- Sebastian L. B. König
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK, Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland and University of Nice-Sophia Antipolis, UMR 7272 CNRS, Institut de 40 Chimie de Nice, 28 Avenue Valrose, 06108 Nice, France
| | - Julian L. Huppert
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK, Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland and University of Nice-Sophia Antipolis, UMR 7272 CNRS, Institut de 40 Chimie de Nice, 28 Avenue Valrose, 06108 Nice, France
| | - Roland K. O. Sigel
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK, Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland and University of Nice-Sophia Antipolis, UMR 7272 CNRS, Institut de 40 Chimie de Nice, 28 Avenue Valrose, 06108 Nice, France
| | - Amanda C. Evans
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK, Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland and University of Nice-Sophia Antipolis, UMR 7272 CNRS, Institut de 40 Chimie de Nice, 28 Avenue Valrose, 06108 Nice, France
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Damerla RR, Knickelbein KE, Strutt S, Liu FJ, Wang H, Opresko PL. Werner syndrome protein suppresses the formation of large deletions during the replication of human telomeric sequences. Cell Cycle 2012; 11:3036-44. [PMID: 22871734 DOI: 10.4161/cc.21399] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Werner syndrome (WS) is a disorder characterized by features of premature aging and increased cancer that is caused by loss of the RecQ helicase WRN. Telomeres consisting of duplex TTAGGG repeats in humans protect chromosome ends and sustain cellular proliferation. WRN prevents the loss of telomeres replicated from the G-rich strand, which can form secondary G-quadruplex (G4) structures. Here, we dissected WRN roles in the replication of telomeric sequences by examining factors inherent to telomeric repeats, such as G4 DNA, independently from other factors at chromosome ends that can also impede replication. For this we used the supF shuttle vector (SV) mutagenesis assay. We demonstrate that SVs with [TTAGGG]6 sequences are stably replicated in human cells, and that the repeats suppress the frequency of large deletions despite G4 folding potential. WRN depletion increased the supF mutant frequency for both the telomeric and non-telomeric SVs, compared with the control cells, but this increase was much greater (27-fold) for telomeric SVs. The higher SV mutant frequencies in WRN-deficient cells were primarily due to an increase in large sequence deletions and rearrangements. However, WRN depletion caused a more dramatic increase in deletions and rearrangements arising within the telomeric SV (70-fold), compared with non-telomeric SV (8-fold). Our results indicate that WRN prevents large deletions and rearrangements during replication, and that this role is particularly important in templates with telomeric sequence. This provides a possible explanation for increased telomere loss in WS cells.
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Affiliation(s)
- Rama Rao Damerla
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA
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