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Fouks B, Miller KJ, Ross C, Jones C, Rueppell O. Alternative double strand break repair pathways shape the evolution of high recombination in the honey bee, Apis mellifera. INSECT MOLECULAR BIOLOGY 2025; 34:185-202. [PMID: 39297191 PMCID: PMC11705527 DOI: 10.1111/imb.12961] [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] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Accepted: 09/02/2024] [Indexed: 01/11/2025]
Abstract
Social insects, particularly honey bees, have exceptionally high genomic frequencies of genetic recombination. This phenomenon and underlying mechanisms are poorly understood. To characterise the patterns of crossovers and gene conversion in the honey bee genome, a recombination map of 187 honey bee brothers was generated by whole-genome resequencing. Recombination events were heterogeneously distributed without many true hotspots. The tract lengths between phase shifts were bimodally distributed, indicating distinct crossover and gene conversion events. While crossovers predominantly occurred in G/C-rich regions and seemed to cause G/C enrichment, the gene conversions were found predominantly in A/T-rich regions. The nucleotide composition of sequences involved in gene conversions that were associated with or distant from crossovers corresponded to the differences between crossovers and gene conversions. These combined results suggest two types of DNA double-strand break repair during honey bee meiosis: non-canonical homologous recombination, leading to gene conversion and A/T enrichment of the genome, and the canonical homologous recombination based on completed double Holliday Junctions, which can result in gene conversion or crossover and is associated with G/C bias. This G/C bias may be selected for to balance the A/T-rich base composition of eusocial hymenopteran genomes. The lack of evidence for a preference of the canonical homologous recombination for double-strand break repair suggests that the high genomic recombination rate of honey bees is mainly the consequence of a high rate of double-strand breaks, which could in turn result from the life history of honey bees and their A/T-rich genome.
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Affiliation(s)
- Bertrand Fouks
- Department of BiologyUniversity of North Carolina at GreensboroGreensboroNorth CarolinaUSA
- UMR AGAP Institut, Univ Montpellier, CIRAD, INRAE, Institut AgroMontpellierFrance
- CIRAD, UMR AGAP InstitutMontpellierFrance
| | - Katelyn J. Miller
- Department of BiologyUniversity of North Carolina at GreensboroGreensboroNorth CarolinaUSA
- Smithers PDSGaithersburgMarylandUSA
| | - Caitlin Ross
- Department of Computer SciencesUniversity of North Carolina at GreensboroGreensboroNorth CarolinaUSA
- KitwareMinneapolisMinnesotaUSA
| | - Corbin Jones
- Department of BiologyUniversity of North Carolina at Chapel Hill & Carolina Center for Genome SciencesChapel HillNorth CarolinaUSA
| | - Olav Rueppell
- Department of BiologyUniversity of North Carolina at GreensboroGreensboroNorth CarolinaUSA
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
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2
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Das M, Hile S, Brewster J, Boer J, Bezalel-Buch R, Guo Q, Yang W, Burgers P, Eckert K, Freudenreich C. DNA polymerase zeta can efficiently replicate structures formed by AT/TA repeat sequences and prevent their deletion. Nucleic Acids Res 2025; 53:gkae1254. [PMID: 39727171 PMCID: PMC11797062 DOI: 10.1093/nar/gkae1254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/03/2024] [Accepted: 12/06/2024] [Indexed: 12/28/2024] Open
Abstract
Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence. DNA polymerase eta is not protective for deletions at AT-rich structures, while DNA polymerase delta is protective, but not in a repeat-specific manner. Using purified replicative holoenzymes in vitro, we show that hairpin structures are most inhibitory to yeast DNA polymerase epsilon, whereas yeast and human Pol ζ efficiently synthesize these regions in a stepwise manner. A requirement for the Rev1 protein and the modifiable lysine 164 of proliferating cell nuclear antigen to prevent deletions at AT/TA repeats suggests a mechanism for Pol ζ recruitment. Our results reveal a novel role for Pol ζ in replicating through AT-rich hairpins and suggest a role for Pol ζ in rescue of stalled replication forks caused by DNA structures.
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Affiliation(s)
- Mili Das
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Suzanne E Hile
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Jennifer Brewster
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Jan Leendert Boer
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
| | - Rachel Bezalel-Buch
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Qiong Guo
- Mechanism of DNA Repair, Replication, and Recombination Section, Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Wei Yang
- Mechanism of DNA Repair, Replication, and Recombination Section, Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Peter M Burgers
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Kristin A Eckert
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA
- Program in Genetics, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
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3
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Cooke MB, Herman C, Sivaramakrishnan P. Clues to transcription/replication collision-induced DNA damage: it was RNAP, in the chromosome, with the fork. FEBS Lett 2025; 599:209-243. [PMID: 39582266 DOI: 10.1002/1873-3468.15063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2024] [Revised: 10/14/2024] [Accepted: 10/25/2024] [Indexed: 11/26/2024]
Abstract
DNA replication and RNA transcription processes compete for the same DNA template and, thus, frequently collide. These transcription-replication collisions are thought to lead to genomic instability, which places a selective pressure on organisms to avoid them. Here, we review the predisposing causes, molecular mechanisms, and downstream consequences of transcription-replication collisions (TRCs) with a strong emphasis on prokaryotic model systems, before contrasting prokaryotic findings with cases in eukaryotic systems. Current research points to genomic structure as the primary determinant of steady-state TRC levels and RNA polymerase regulation as the primary inducer of excess TRCs. We review the proposed mechanisms of TRC-induced DNA damage, attempting to clarify their mechanistic requirements. Finally, we discuss what drives genomes to select against TRCs.
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Affiliation(s)
- Matthew B Cooke
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Priya Sivaramakrishnan
- Center for Computational and Genomic Medicine, Children's Hospital of Philadelphia, PA, USA
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4
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Xie FY, Zhang XG, Chen J, Xu X, Li S, Xia TJ, Chen LN, Yin S, Ou XH, Ma JY. Downstream transcription promotes human recurrent CNV associated AT-rich sequence mediated genome rearrangements in yeast. iScience 2024; 27:111508. [PMID: 39758996 PMCID: PMC11697705 DOI: 10.1016/j.isci.2024.111508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 09/29/2024] [Accepted: 11/27/2024] [Indexed: 01/07/2025] Open
Abstract
AT-rich sequence can cause structure variants such as translocations and its instability can be accelerated by replication stresses. When human 16p11.2 or 22q11.2 recurrent copy number variant (reCNV) associated AT-rich sequence was inserted upstream GAL1 promoter in yeast genome, we found that downstream transcription could promote AT-rich forming cruciform structure and mediate gross genome rearrangements. When genes were flanked with direct repeats containing AT-rich sequence, copy number loss of these genes would be stimulated. Transcription-mediated AT-rich instability can be alleviated by disrupting MUS81 or YEN1 and exacerbated by disrupting RAD1/10. Deletion of homologous recombination-associated genes can not only increase AT-rich fragility but also alter the breakpoint positions. AT-rich stability was also affected by DNA topoisomerase poisons. Our results reveal that transcription can promote AT-rich-mediated de novo genome rearrangement, which might be helpful for understanding the mechanism of reCNV formation in humans.
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Affiliation(s)
- Feng-Yun Xie
- Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
| | - Xiao-Guohui Zhang
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Juan Chen
- Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
| | - Xin Xu
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
| | - Sen Li
- Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
| | - Tian-Jin Xia
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Lei-Ning Chen
- Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
| | - Shen Yin
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Xiang-Hong Ou
- Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
| | - Jun-Yu Ma
- Guangzhou Municipal Key Laboratory of Metabolic Diseases and Reproductive Health, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
- Reproductive Medicine Center, The Affiliated Guangdong Second Provincial General Hospital of Jinan University, Guangzhou, China
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5
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Gupta A, Avadhanula S, Bashyam MD. Evaluation of the gene fusion landscape in early onset sporadic rectal cancer reveals association with chromatin architecture and genome stability. Oncogene 2024; 43:2449-2462. [PMID: 38937601 DOI: 10.1038/s41388-024-03088-z] [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: 04/11/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 06/29/2024]
Abstract
Gene fusions represent a distinct class of structural variants identified frequently in cancer genomes across cancer types. Several gene fusions exhibit gain of oncogenic function and thus have been the focus of development of efficient targeted therapies. However, investigation of fusion landscape in early-onset sporadic rectal cancer, a poorly studied colorectal cancer subtype prevalent in developing countries, has not been performed. Here, we present a comprehensive landscape of gene fusions in EOSRC and CRC using patient derived tumor samples and data from The Cancer Genome Atlas, respectively. Gene Ontology analysis revealed enrichment of unique biological process terms associated with 5'- and 3'- fusion partner genes. Extensive network analysis highlighted genes exhibiting significant promiscuity in fusion formation and their association with chromosome fragile sites. Investigation of fusion formation in the context of global chromatin architecture unraveled a novel mode of gene activation that arose from fusion between genes located in orthogonal chromatin compartments. The study provides novel evidence linking fusions to genome stability and architecture and unearthed a hitherto unidentified mode of gene activation in cancer.
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Affiliation(s)
- Asmita Gupta
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Sumedha Avadhanula
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Murali Dharan Bashyam
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.
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6
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Pytko KG, Dannenberg RL, Eckert KA, Hedglin M. Replication of [AT/TA] 25 Microsatellite Sequences by Human DNA Polymerase δ Holoenzymes Is Dependent on dNTP and RPA Levels. Biochemistry 2024; 63:969-983. [PMID: 38623046 PMCID: PMC12121678 DOI: 10.1021/acs.biochem.4c00006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Fragile sites are unstable genomic regions that are prone to breakage during stressed DNA replication. Several common fragile sites (CFS) contain A+T-rich regions including perfect [AT/TA] microsatellite repeats that may collapse into hairpins when in single-stranded DNA (ssDNA) form and coincide with chromosomal hotspots for breakage and rearrangements. While many factors contribute to CFS instability, evidence exists for replication stalling within [AT/TA] microsatellite repeats. Currently, it is unknown how stress causes replication stalling within [AT/TA] microsatellite repeats. To investigate this, we utilized FRET to characterize the structures of [AT/TA]25 sequences and also reconstituted lagging strand replication to characterize the progression of pol δ holoenzymes through A+T-rich sequences. The results indicate that [AT/TA]25 sequences adopt hairpins that are unwound by the major ssDNA-binding complex, RPA, and the progression of pol δ holoenzymes through A+T-rich sequences saturated with RPA is dependent on the template sequence and dNTP concentration. Importantly, the effects of RPA on the replication of [AT/TA]25 sequences are dependent on dNTP concentration, whereas the effects of RPA on the replication of A+T-rich, nonstructure-forming sequences are independent of dNTP concentration. Collectively, these results reveal complexities in lagging strand replication and provide novel insights into how [AT/TA] microsatellite repeats contribute to genome instability.
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Affiliation(s)
- Kara G Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Rachel L Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
| | - Kristin A Eckert
- Department of Pathology and Laboratory Medicine, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, United States
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, United States
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7
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Cook D, Kozmin SG, Yeh E, Petes TD, Bloom K. Dicentric chromosomes are resolved through breakage and repair at their centromeres. Chromosoma 2024; 133:117-134. [PMID: 38165460 PMCID: PMC11180013 DOI: 10.1007/s00412-023-00814-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/11/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Chromosomes with two centromeres provide a unique opportunity to study chromosome breakage and DNA repair using completely endogenous cellular machinery. Using a conditional transcriptional promoter to control the second centromere, we are able to activate the dicentric chromosome and follow the appearance of DNA repair products. We find that the rate of appearance of DNA repair products resulting from homology-based mechanisms exceeds the expected rate based on their limited centromere homology (340 bp) and distance from one another (up to 46.3 kb). In order to identify whether DNA breaks originate in the centromere, we introduced 12 single-nucleotide polymorphisms (SNPs) into one of the centromeres. Analysis of the distribution of SNPs in the recombinant centromeres reveals that recombination was initiated with about equal frequency within the conserved centromere DNA elements CDEII and CDEIII of the two centromeres. The conversion tracts range from about 50 bp to the full length of the homology between the two centromeres (340 bp). Breakage and repair events within and between the centromeres can account for the efficiency and distribution of DNA repair products. We propose that in addition to providing a site for kinetochore assembly, the centromere may be a point of stress relief in the face of genomic perturbations.
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Affiliation(s)
- Diana Cook
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599-3280, USA
| | - Stanislav G Kozmin
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Elaine Yeh
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599-3280, USA
| | - Thomas D Petes
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Kerry Bloom
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, 27599-3280, USA.
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8
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Scelfo A, Angrisani A, Grillo M, Barnes BM, Muyas F, Sauer CM, Leung CWB, Dumont M, Grison M, Mazaud D, Garnier M, Guintini L, Nelson L, Esashi F, Cortés-Ciriano I, Taylor SS, Déjardin J, Wilhelm T, Fachinetti D. Specialized replication mechanisms maintain genome stability at human centromeres. Mol Cell 2024; 84:1003-1020.e10. [PMID: 38359824 DOI: 10.1016/j.molcel.2024.01.018] [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: 03/13/2023] [Revised: 12/12/2023] [Accepted: 01/19/2024] [Indexed: 02/17/2024]
Abstract
The high incidence of whole-arm chromosome aneuploidy and translocations in tumors suggests instability of centromeres, unique loci built on repetitive sequences and essential for chromosome separation. The causes behind this fragility and the mechanisms preserving centromere integrity remain elusive. We show that replication stress, hallmark of pre-cancerous lesions, promotes centromeric breakage in mitosis, due to spindle forces and endonuclease activities. Mechanistically, we unveil unique dynamics of the centromeric replisome distinct from the rest of the genome. Locus-specific proteomics identifies specialized DNA replication and repair proteins at centromeres, highlighting them as difficult-to-replicate regions. The translesion synthesis pathway, along with other factors, acts to sustain centromere replication and integrity. Prolonged stress causes centromeric alterations like ruptures and translocations, as observed in ovarian cancer models experiencing replication stress. This study provides unprecedented insights into centromere replication and integrity, proposing mechanistic insights into the origins of centromere alterations leading to abnormal cancerous karyotypes.
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Affiliation(s)
- Andrea Scelfo
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France
| | - Annapaola Angrisani
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France
| | - Marco Grillo
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France
| | - Bethany M Barnes
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Cancer Research Centre, Wilmslow Road, Manchester M20 4GJ, UK
| | - Francesc Muyas
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge CB10 1SD, UK
| | - Carolin M Sauer
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge CB10 1SD, UK
| | | | - Marie Dumont
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France
| | - Marine Grison
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France
| | - David Mazaud
- Plateforme Imagerie PICT-IBiSA, Institut Curie, PSL Research University, Paris 75005, France; Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR3664, 26 rue d'Ulm, Paris 75005, France
| | - Mickaël Garnier
- Plateforme Imagerie PICT-IBiSA, Institut Curie, PSL Research University, Paris 75005, France; Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR3664, 26 rue d'Ulm, Paris 75005, France
| | - Laetitia Guintini
- Institute of Human Genetics, CNRS-Université de Montpellier, Montpellier 34396, France
| | - Louisa Nelson
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Cancer Research Centre, Wilmslow Road, Manchester M20 4GJ, UK
| | - Fumiko Esashi
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Isidro Cortés-Ciriano
- European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridge CB10 1SD, UK
| | - Stephen S Taylor
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Cancer Research Centre, Wilmslow Road, Manchester M20 4GJ, UK
| | - Jérôme Déjardin
- Institute of Human Genetics, CNRS-Université de Montpellier, Montpellier 34396, France
| | - Therese Wilhelm
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France; Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR3664, 26 rue d'Ulm, Paris 75005, France.
| | - Daniele Fachinetti
- Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR144, 26 rue d'Ulm, Paris 75005, France; Institut Curie, PSL Research University, Sorbonne Université, CNRS, UMR3664, 26 rue d'Ulm, Paris 75005, France.
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9
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Li Y, Zhang Y, Shah SB, Chang CY, Wang H, Wu X. MutSβ protects common fragile sites by facilitating homology-directed repair at DNA double-strand breaks with secondary structures. Nucleic Acids Res 2024; 52:1120-1135. [PMID: 38038265 PMCID: PMC10853791 DOI: 10.1093/nar/gkad1112] [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: 08/10/2023] [Revised: 10/14/2023] [Accepted: 11/07/2023] [Indexed: 12/02/2023] Open
Abstract
Common fragile sites (CFSs) are regions prone to chromosomal rearrangements, thereby contributing to tumorigenesis. Under replication stress (RS), CFSs often harbor under-replicated DNA regions at the onset of mitosis, triggering homology-directed repair known as mitotic DNA synthesis (MiDAS) to complete DNA replication. In this study, we identified an important role of DNA mismatch repair protein MutSβ (MSH2/MSH3) in facilitating MiDAS and maintaining CFS stability. Specifically, we demonstrated that MutSβ is required for the increased mitotic recombination induced by RS or FANCM loss at CFS-derived AT-rich and structure-prone sequences (CFS-ATs). We also found that MSH3 exhibits synthetic lethality with FANCM. Mechanistically, MutSβ is required for homologous recombination (HR) especially when DNA double-strand break (DSB) ends contain secondary structures. We also showed that upon RS, MutSβ is recruited to Flex1, a specific CFS-AT, in a PCNA-dependent but MUS81-independent manner. Furthermore, MutSβ interacts with RAD52 and promotes RAD52 recruitment to Flex1 following MUS81-dependent fork cleavage. RAD52, in turn, recruits XPF/ERCC1 to remove DNA secondary structures at DSB ends, enabling HR/break-induced replication (BIR) at CFS-ATs. We propose that the specific requirement of MutSβ in processing DNA secondary structures at CFS-ATs underlies its crucial role in promoting MiDAS and maintaining CFS integrity.
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Affiliation(s)
- Youhang Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Yunkun Zhang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Sameer Bikram Shah
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Chia-Yu Chang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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10
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Sharma M, Larow VM, Dobychina N, Kessler DS, Krasilnikova MM, Yaklichkin S. The evolutionary loss of the Eh1 motif in FoxE1 in the lineage of placental mammals. PLoS One 2023; 18:e0296176. [PMID: 38150428 PMCID: PMC10752562 DOI: 10.1371/journal.pone.0296176] [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: 03/30/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023] Open
Abstract
Forkhead box E1 (FoxE1) protein is a transcriptional regulator known to play a major role in the development of the thyroid gland. By performing sequence alignments, we detected a deletion in FoxE1, which occurred in the evolution of mammals, near the point of divergence of placental mammals. This deletion led to the loss of the majority of the Eh1 motif, which was important for interactions with transcriptional corepressors. To investigate a potential mechanism for this deletion, we analyzed replication through the deletion area in mammalian cells with two-dimensional gel electrophoresis, and in vitro, using a primer extension reaction. We demonstrated that the area of the deletion presented an obstacle for replication in both assays. The exact position of polymerization arrest in primer extension indicated that it was most likely caused by a quadruplex DNA structure. The quadruplex structure hypothesis is also consistent with the exact borders of the deletion. The exact roles of these evolutionary changes in FoxE1 family proteins are still to be determined.
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Affiliation(s)
- Mahak Sharma
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, United States of America
| | - Victoria M. Larow
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, United States of America
| | - Nataliia Dobychina
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
| | - Daniel S. Kessler
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Maria M. Krasilnikova
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, United States of America
| | - Sergey Yaklichkin
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America
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11
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Irony-Tur Sinai M, Kerem B. Insights into common fragile site instability: DNA replication challenges at DNA repeat sequences. Emerg Top Life Sci 2023; 7:277-287. [PMID: 37876349 PMCID: PMC10754330 DOI: 10.1042/etls20230023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/08/2023] [Accepted: 10/12/2023] [Indexed: 10/26/2023]
Abstract
Common fragile sites (CFS) are specific genomic regions prone to chromosomal instability under conditions of DNA replication stress. CFSs manifest as breaks, gaps, and constrictions on metaphase chromosomes under mild replication stress. These replication-sensitive CFS regions are preferentially unstable during cancer development, as reflected by their association with copy number variants (CNVs) frequently arise in most tumor types. Over the years, it became clear that a combination of different characteristics underlies the enhanced sensitivity of CFSs to replication stress. As of today, there is a strong evidence that the core fragility regions along CFSs overlap with actively transcribed large genes with delayed replication timing upon replication stress. Recently, the mechanistic basis for CFS instability was further extended to regions which span topologically associated domain (TAD) boundaries, generating a fragility signature composed of replication, transcription and genome organization. The presence of difficult-to-replicate AT-rich repeats was one of the early features suggested to characterize a subgroup of CFSs. These long stretches of AT-dinucleotide have the potential to fold into stable secondary structures which may impede replication fork progression, leaving the region under-replicated. Here, we focus on the molecular mechanisms underlying repeat instability at CFSs and on the proteins involved in the resolution of secondary structure impediments arising along repetitive sequence elements which are essential for the maintenance of genome stability.
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Affiliation(s)
- Michal Irony-Tur Sinai
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel
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12
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Dong XS, Wen XJ, Zhang S, Wang DG, Xiong Y, Li ZM. Identification of compound heterozygous deletion of the WWOX gene in WOREE syndrome. BMC Med Genomics 2023; 16:291. [PMID: 37974179 PMCID: PMC10652538 DOI: 10.1186/s12920-023-01731-4] [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: 02/22/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Biallelic loss-of-function variants in WWOX cause WWOX-related epileptic encephalopathy (WOREE syndrome), which has been reported in 60 affected individuals to date. In this study, we report on an affected individual with WOREE syndrome who presented with early-onset refractory seizures and global neurodevelopmental delay and died at the age of two and a half years. METHODS We present clinical and molecular findings in the affected individual, including biallelic pathogenic variants in the WWOX gene. We employed different molecular approaches, such as whole exome sequencing, quantitative real-time polymerase chain reaction (qPCR), and whole-genome sequencing, to identify the genetic variants. The breakpoints were determined through gap PCR and Sanger sequencing. RESULT Whole exome sequencing revealed homozygous exon 6 deletion in the WWOX gene in the proband. Quantitative real-time PCR confirmed that the parents were heterozygous carriers of exon 6 deletion. However, using whole-genome sequencing, we identified three larger deletions (maternal allele with exon 6-8 deletion and paternal allele with two deletions in proximity one in intron 5 and the other in exon 6) involving the WWOX gene in the proband, with deletion sizes of 13,261 bp, 53,904 bp, and 177,200 bp. The exact breakpoints were confirmed through gap PCR and Sanger sequencing. We found that the proband inherited the discontinuous deletion of intron 5 and exon 6 from the father, and the exons 6-8 deletion from the mother using gap PCR. CONCLUSION Our findings extend the variant spectrum of WOREE syndrome and support the critical role of the WWOX gene in neural development.
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Affiliation(s)
- Xing-Sheng Dong
- Prenatal Diagnosis Center, Zhongshan Boai Hospital Affiliated to Southern Medical University, Zhongshan, Guangdong, China
| | - Xiao-Jun Wen
- Reproductive Medicine Center, Zhongshan Boai Hospital Affiliated to Southern Medical University, Zhongshan, Guangdong, China
| | - Sheng Zhang
- Department of Pediatrics, Zhongshan Boai Hospital Affiliated to Southern Medical University, Zhongshan, Guangdong, China
| | - De-Gang Wang
- Prenatal Diagnosis Center, Zhongshan Boai Hospital Affiliated to Southern Medical University, Zhongshan, Guangdong, China
| | - Yi Xiong
- Prenatal Diagnosis Center, Zhongshan Boai Hospital Affiliated to Southern Medical University, Zhongshan, Guangdong, China
| | - Zhi-Ming Li
- Prenatal Diagnosis Center, Zhongshan Boai Hospital Affiliated to Southern Medical University, Zhongshan, Guangdong, China.
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13
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Pytko KG, Dannenberg RL, Eckert KA, Hedglin M. Replication of [AT/TA] 25 microsatellite sequences by human DNA polymerase δ holoenzymes is dependent on dNTP and RPA levels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566133. [PMID: 37986888 PMCID: PMC10659299 DOI: 10.1101/2023.11.07.566133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Difficult-to-Replicate Sequences (DiToRS) are natural impediments in the human genome that inhibit DNA replication under endogenous replication. Some of the most widely-studied DiToRS are A+T-rich, high "flexibility regions," including long stretches of perfect [AT/TA] microsatellite repeats that have the potential to collapse into hairpin structures when in single-stranded DNA (ssDNA) form and are sites of recurrent structural variation and double-stranded DNA (dsDNA) breaks. Currently, it is unclear how these flexibility regions impact DNA replication, greatly limiting our fundamental understanding of human genome stability. To investigate replication through flexibility regions, we utilized FRET to characterize the effects of the major ssDNA-binding complex, RPA, on the structure of perfect [AT/TA]25 microsatellite repeats and also re-constituted human lagging strand replication to quantitatively characterize initial encounters of pol δ holoenzymes with A+T-rich DNA template sequences. The results indicate that [AT/TA]25 sequences adopt hairpin structures that are unwound by RPA and pol δ holoenzymes support dNTP incorporation through the [AT/TA]25 sequences as well as an A+T-rich, non-structure forming sequence. Furthermore, the extent of dNTP incorporation is dependent on the sequence of the DNA template and the concentration of dNTPs. Importantly, the effects of RPA on the replication of [AT/TA]25 sequences are dependent on the concentration of dNTPs, whereas the effects of RPA on the replication of an A+T-rich, non-structure forming sequence are independent of dNTP concentration. Collectively, these results reveal complexities in lagging strand replication and provide novel insights into how flexibility regions contribute to genome instability.
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Affiliation(s)
- Kara G. Pytko
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Rachel L. Dannenberg
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
| | - Kristin A. Eckert
- Department of Pathology and Laboratory Medicine, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033
| | - Mark Hedglin
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802
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14
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Matos-Rodrigues G, Hisey JA, Nussenzweig A, Mirkin SM. Detection of alternative DNA structures and its implications for human disease. Mol Cell 2023; 83:3622-3641. [PMID: 37863029 DOI: 10.1016/j.molcel.2023.08.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/01/2023] [Accepted: 08/16/2023] [Indexed: 10/22/2023]
Abstract
Around 3% of the genome consists of simple DNA repeats that are prone to forming alternative (non-B) DNA structures, such as hairpins, cruciforms, triplexes (H-DNA), four-stranded guanine quadruplexes (G4-DNA), and others, as well as composite RNA:DNA structures (e.g., R-loops, G-loops, and H-loops). These DNA structures are dynamic and favored by the unwinding of duplex DNA. For many years, the association of alternative DNA structures with genome function was limited by the lack of methods to detect them in vivo. Here, we review the recent advancements in the field and present state-of-the-art technologies and methods to study alternative DNA structures. We discuss the limitations of these methods as well as how they are beginning to provide insights into causal relationships between alternative DNA structures, genome function and stability, and human disease.
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Affiliation(s)
| | - Julia A Hisey
- Department of Biology, Tufts University, Medford, MA, USA
| | - André Nussenzweig
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD, USA.
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15
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Benitez A, Sebald M, Kanagaraj R, Rodrigo-Brenni MC, Chan YW, Liang CC, West SC. GEN1 promotes common fragile site expression. Cell Rep 2023; 42:112062. [PMID: 36729836 DOI: 10.1016/j.celrep.2023.112062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 11/01/2022] [Accepted: 01/18/2023] [Indexed: 02/03/2023] Open
Abstract
Our genomes harbor conserved DNA sequences, known as common fragile sites (CFSs), that are difficult to replicate and correspond to regions of genome instability. Following replication stress, CFS loci give rise to breaks or gaps (termed CFS expression) where under-replicated DNA subsequently undergoes mitotic DNA synthesis (MiDAS). We show that loss of the structure-selective endonuclease GEN1 reduces CFS expression, leading to defects in MiDAS, ultrafine anaphase bridge formation, and DNA damage in the ensuing cell cycle due to aberrant chromosome segregation. GEN1 knockout cells also exhibit an elevated frequency of bichromatid constrictions consistent with the presence of unresolved regions of under-replicated DNA. Previously, the role of GEN1 was thought to be restricted to the nucleolytic resolution of recombination intermediates. However, its ability to cleave under-replicated DNA at CFS loci indicates that GEN1 plays a dual role resolving both DNA replication and recombination intermediates before chromosome segregation.
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Affiliation(s)
- Anaid Benitez
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK
| | - Marie Sebald
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK
| | - Radhakrishnan Kanagaraj
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK
| | - Monica C Rodrigo-Brenni
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK
| | - Ying Wai Chan
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK
| | - Chih-Chao Liang
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK
| | - Stephen C West
- The Francis Crick Institute, DNA Recombination and Repair Laboratory, 1 Midland Road, London NW1 1AT, UK.
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16
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Rider SD, Damewood FJ, Gadgil RY, Hitch DC, Alhawach V, Shrestha R, Shanahan M, Zavada N, Leffak M. Suppressors of Break-Induced Replication in Human Cells. Genes (Basel) 2023; 14:genes14020398. [PMID: 36833325 PMCID: PMC9956954 DOI: 10.3390/genes14020398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/23/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Short tandem DNA repeats are drivers of genome instability. To identify suppressors of break-induced mutagenesis human cells, unbiased genetic screens were conducted using a lentiviral shRNA library. The recipient cells possessed fragile non-B DNA that could induce DNA double-strand breaks (DSBs), integrated at an ectopic chromosomal site adjacent to a thymidine kinase marker gene. Mutagenesis of the thymidine kinase gene rendered cells resistant to the nucleoside analog ganciclovir (GCV). The screen identified genes that have established roles in DNA replication and repair, chromatin modification, responses to ionizing radiation, and genes encoding proteins enriched at replication forks. Novel loci implicated in BIR included olfactory receptors, the G0S2 oncogene/tumor suppressor axis, the EIF3H-METTL3 translational regulator, and the SUDS3 subunit of the Sin3A corepressor. Consistent with a role in suppressing BIR, siRNA knockdown of selected candidates increased the frequency of the GCVr phenotype and increased DNA rearrangements near the ectopic non-B DNA. Inverse PCR and DNA sequence analyses showed that hits identified in the screen increased genome instability. Further analysis quantitated repeat-induced hypermutagenesis at the ectopic site and showed that knockdown of a primary hit, COPS2, induced mutagenic hotspots, remodeled the replication fork, and increased nonallelic chromosome template switches.
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17
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DNA repair protein RAD52 is required for protecting G-quadruplexes in mammalian cells. J Biol Chem 2022; 299:102770. [PMID: 36470428 PMCID: PMC9807996 DOI: 10.1016/j.jbc.2022.102770] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 12/09/2022] Open
Abstract
G-quadruplex (G4)-forming DNA sequences are abundant in the human genome, and they are hot spots for inducing DNA double-strand breaks (DSBs) and genome instability. The mechanisms involved in protecting G4s and maintaining genome stability have not been fully elucidated. Here, we demonstrated that RAD52 plays an important role in suppressing DSB accumulation at G4s, and RAD52-deficient cells are sensitive to G4-stabilizing compounds. Mechanistically, we showed that RAD52 is required for efficient homologous recombination repair at G4s, likely due to its function in recruiting structure-specific endonuclease XPF to remove G4 structures at DSB ends. We also demonstrated that upon G4 stabilization, endonuclease MUS81 mediates cleavage of stalled replication forks at G4s. The resulting DSBs recruit RAD52 and XPF to G4s for processing DSB ends to facilitate homologous recombination repair. Loss of RAD52 along with G4-resolving helicase FANCJ leads to a significant increase of DSB accumulation before and after treatment with the G4-stabilizing compound pyridostatin, and RAD52 exhibits a synthetic lethal interaction with FANCJ. Collectively, our findings reveal a new role of RAD52 in protecting G4 integrity and provide insights for new cancer treatment strategies.
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18
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Mirceta M, Shum N, Schmidt MHM, Pearson CE. Fragile sites, chromosomal lesions, tandem repeats, and disease. Front Genet 2022; 13:985975. [PMID: 36468036 PMCID: PMC9714581 DOI: 10.3389/fgene.2022.985975] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/02/2022] [Indexed: 09/16/2023] Open
Abstract
Expanded tandem repeat DNAs are associated with various unusual chromosomal lesions, despiralizations, multi-branched inter-chromosomal associations, and fragile sites. Fragile sites cytogenetically manifest as localized gaps or discontinuities in chromosome structure and are an important genetic, biological, and health-related phenomena. Common fragile sites (∼230), present in most individuals, are induced by aphidicolin and can be associated with cancer; of the 27 molecularly-mapped common sites, none are associated with a particular DNA sequence motif. Rare fragile sites ( ≳ 40 known), ≤ 5% of the population (may be as few as a single individual), can be associated with neurodevelopmental disease. All 10 molecularly-mapped folate-sensitive fragile sites, the largest category of rare fragile sites, are caused by gene-specific CGG/CCG tandem repeat expansions that are aberrantly CpG methylated and include FRAXA, FRAXE, FRAXF, FRA2A, FRA7A, FRA10A, FRA11A, FRA11B, FRA12A, and FRA16A. The minisatellite-associated rare fragile sites, FRA10B, FRA16B, can be induced by AT-rich DNA-ligands or nucleotide analogs. Despiralized lesions and multi-branched inter-chromosomal associations at the heterochromatic satellite repeats of chromosomes 1, 9, 16 are inducible by de-methylating agents like 5-azadeoxycytidine and can spontaneously arise in patients with ICF syndrome (Immunodeficiency Centromeric instability and Facial anomalies) with mutations in genes regulating DNA methylation. ICF individuals have hypomethylated satellites I-III, alpha-satellites, and subtelomeric repeats. Ribosomal repeats and subtelomeric D4Z4 megasatellites/macrosatellites, are associated with chromosome location, fragility, and disease. Telomere repeats can also assume fragile sites. Dietary deficiencies of folate or vitamin B12, or drug insults are associated with megaloblastic and/or pernicious anemia, that display chromosomes with fragile sites. The recent discovery of many new tandem repeat expansion loci, with varied repeat motifs, where motif lengths can range from mono-nucleotides to megabase units, could be the molecular cause of new fragile sites, or other chromosomal lesions. This review focuses on repeat-associated fragility, covering their induction, cytogenetics, epigenetics, cell type specificity, genetic instability (repeat instability, micronuclei, deletions/rearrangements, and sister chromatid exchange), unusual heritability, disease association, and penetrance. Understanding tandem repeat-associated chromosomal fragile sites provides insight to chromosome structure, genome packaging, genetic instability, and disease.
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Affiliation(s)
- Mila Mirceta
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Natalie Shum
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Monika H. M. Schmidt
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Christopher E. Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, ON, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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19
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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: 36] [Impact Index Per Article: 12.0] [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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20
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Abstract
The enormous diversity of antibodies is a key element to combat infections. Antibodies containing pathogen receptors were a surprising discovery that contrasted antibody diversification through classic recombination events. However, such insert-containing antibodies were thus far exclusively detected in African individuals exposed to malaria parasites and were identified as screening byproducts or through hypothesis-driven search. The prevalence and complexity of insertion events remained elusive. In this study, we devise an unbiased, systematic approach to identify inserts in the human antibody repertoire. We show that inserts from distant genomic regions occur in the majority of donors and are independent of Plasmodium falciparum preexposure. Our findings suggest that four distinct classes of insertion events contribute diversity to the human antibody repertoire. Recombination of antibody genes in B cells can involve distant genomic loci and contribute a foreign antigen-binding element to form hybrid antibodies with broad reactivity for Plasmodium falciparum. So far, antibodies containing the extracellular domain of the LAIR1 and LILRB1 receptors represent unique examples of cross-chromosomal antibody diversification. Here, we devise a technique to profile non-VDJ elements from distant genes in antibody transcripts. Independent of the preexposure of donors to malaria parasites, non-VDJ inserts were detected in 80% of individuals at frequencies of 1 in 104 to 105 B cells. We detected insertions in heavy, but not in light chain or T cell receptor transcripts. We classify the insertions into four types depending on the insert origin and destination: 1) mitochondrial and 2) nuclear DNA inserts integrated at VDJ junctions; 3) inserts originating from telomere proximal genes; and 4) fragile sites incorporated between J-to-constant junctions. The latter class of inserts was exclusively found in memory and in in vitro activated B cells, while all other classes were already detected in naïve B cells. More than 10% of inserts preserved the reading frame, including transcripts with signs of antigen-driven affinity maturation. Collectively, our study unravels a mechanism of antibody diversification that is layered on the classical V(D)J and switch recombination.
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21
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Zou Y, Luo J, Tang Z, Fu S. Variations of wheat ( Triticum aestivum L.) chromosomes caused by the 5A chromosomes with complex cytological structure. FRONTIERS IN PLANT SCIENCE 2022; 13:992934. [PMID: 36105696 PMCID: PMC9465395 DOI: 10.3389/fpls.2022.992934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
To study the effects of structural alterations of chromosomes caused by tandem repeats on the meiotic recombination, the wheat (Triticum aestivum L.) 5A chromosomes with different structure from ten wheat cultivars were used to investigate their meiotic recombination using non-denaturing fluorescence in situ hybridization (ND-FISH) technology. Fifteen cross combinations were carried out and they were divided into seven F1 categories. The structural difference between the intercalary regions of the long arms of the two 5A chromosomes (5AL) in the F1 categories III, VI, and VII was greater than that in the categories I and II, subsequently, the recombination frequencies in the distal regions of the 5AL arm in the progenies from the three categories were significantly lower than that from the categories I and II. For the two 5A chromosomes in the F1 categories VI and VII, the structural differences in the distal regions of both of the two arms were greater than that in the categories IV and V. So, the recombination frequencies in the intercalary region of the 5AL arm in the progeny from the categories IV and V were higher than that in the progeny from the categories VI and VII. The breakage of 5A chromosome together with the 5A translocations and the breakage of some other chromosomes were observed in the progeny from the F1 categories V, VI, and VII. These chromosomal variations were not observed in the progenies from the other four F1 categories. In conclusion, the smaller structural difference between the 5A chromosomes in distal regions of the two arms resulted in a higher recombination frequency in interstitial region and vice versa. The 5A chromosome with complex cytological structure can be used to induce genetic variations of wheat genome.
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Affiliation(s)
- Yang Zou
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
| | - Jie Luo
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
| | - Zongxiang Tang
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
| | - Shulan Fu
- College of Agronomy, Sichuan Agricultural University, Chengdu, China
- Provincial Key Laboratory for Plant Genetics and Breeding, Chengdu, China
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22
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Ji F, Zhu X, Liao H, Ouyang L, Huang Y, Syeda MZ, Ying S. New Era of Mapping and Understanding Common Fragile Sites: An Updated Review on Origin of Chromosome Fragility. Front Genet 2022; 13:906957. [PMID: 35669181 PMCID: PMC9164283 DOI: 10.3389/fgene.2022.906957] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Common fragile sites (CFSs) are specific genomic loci prone to forming gaps or breakages upon replication perturbation, which correlate well with chromosomal rearrangement and copy number variation. CFSs have been actively studied due to their important pathophysiological relevance in different diseases such as cancer and neurological disorders. The genetic locations and sequences of CFSs are crucial to understanding the origin of such unstable sites, which require reliable mapping and characterizing approaches. In this review, we will inspect the evolving techniques for CFSs mapping, especially genome-wide mapping and sequencing of CFSs based on current knowledge of CFSs. We will also revisit the well-established hypotheses on the origin of CFSs fragility, incorporating novel findings from the comprehensive analysis of finely mapped CFSs regarding their locations, sequences, and replication/transcription, etc. This review will present the most up-to-date picture of CFSs and, potentially, a new framework for future research of CFSs.
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Affiliation(s)
- Fang Ji
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China.,Department of Pharmacology and Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Xinli Zhu
- Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Hongwei Liao
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China.,Department of Pharmacology and Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Liujian Ouyang
- Department of Pharmacology and Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Yingfei Huang
- Department of Pharmacology and Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Madiha Zahra Syeda
- Department of Pharmacology and Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Songmin Ying
- International Institutes of Medicine, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China.,Department of Pharmacology and Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Key Laboratory of Respiratory Disease of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
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Translesion polymerase eta both facilitates DNA replication and promotes increased human genetic variation at common fragile sites. Proc Natl Acad Sci U S A 2021; 118:2106477118. [PMID: 34815340 PMCID: PMC8640788 DOI: 10.1073/pnas.2106477118] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2021] [Indexed: 01/23/2023] Open
Abstract
Common fragile sites (CFSs) are difficult-to-replicate genomic regions that form gaps and breaks on metaphase chromosomes under replication stress. They are hotspots for chromosomal instability in cancer. Repetitive sequences located at CFS loci are inefficiently copied by replicative DNA polymerase (Pol) delta. However, translesion synthesis Pol eta has been shown to efficiently polymerize CFS-associated repetitive sequences in vitro and facilitate CFS stability by a mechanism that is not fully understood. Here, by locus-specific, single-molecule replication analysis, we identified a crucial role for Pol eta (encoded by the gene POLH) in the in vivo replication of CFSs, even without exogenous stress. We find that Pol eta deficiency induces replication pausing, increases initiation events, and alters the direction of replication-fork progression at CFS-FRA16D in both lymphoblasts and fibroblasts. Furthermore, certain replication pause sites at CFS-FRA16D were associated with the presence of non-B DNA-forming motifs, implying that non-B DNA structures could increase replication hindrance in the absence of Pol eta. Further, in Pol eta-deficient fibroblasts, there was an increase in fork pausing at fibroblast-specific CFSs. Importantly, while not all pause sites were associated with non-B DNA structures, they were embedded within regions of increased genetic variation in the healthy human population, with mutational spectra consistent with Pol eta activity. From these findings, we propose that Pol eta replicating through CFSs may result in genetic variations found in the human population at these sites.
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Fitzgerald DM, Rosenberg SM. Biology before the SOS Response-DNA Damage Mechanisms at Chromosome Fragile Sites. Cells 2021; 10:2275. [PMID: 34571923 PMCID: PMC8465572 DOI: 10.3390/cells10092275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 01/03/2023] Open
Abstract
The Escherichia coli SOS response to DNA damage, discovered and conceptualized by Evelyn Witkin and Miroslav Radman, is the prototypic DNA-damage stress response that upregulates proteins of DNA protection and repair, a radical idea when formulated in the late 1960s and early 1970s. SOS-like responses are now described across the tree of life, and similar mechanisms of DNA-damage tolerance and repair underlie the genome instability that drives human cancer and aging. The DNA damage that precedes damage responses constitutes upstream threats to genome integrity and arises mostly from endogenous biology. Radman's vision and work on SOS, mismatch repair, and their regulation of genome and species evolution, were extrapolated directly from bacteria to humans, at a conceptual level, by Radman, then many others. We follow his lead in exploring bacterial molecular genomic mechanisms to illuminate universal biology, including in human disease, and focus here on some events upstream of SOS: the origins of DNA damage, specifically at chromosome fragile sites, and the engineered proteins that allow us to identify mechanisms. Two fragility mechanisms dominate: one at replication barriers and another associated with the decatenation of sister chromosomes following replication. DNA structures in E. coli, additionally, suggest new interpretations of pathways in cancer evolution, and that Holliday junctions may be universal molecular markers of chromosome fragility.
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Affiliation(s)
- Devon M. Fitzgerald
- Departments of Molecular and Human Genetics, Biochemistry and Molecular Biology, Molecular Virology and Microbiology, and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Susan M. Rosenberg
- Departments of Molecular and Human Genetics, Biochemistry and Molecular Biology, Molecular Virology and Microbiology, and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Polleys EJ, Freudenreich CH. Homologous recombination within repetitive DNA. Curr Opin Genet Dev 2021; 71:143-153. [PMID: 34464817 DOI: 10.1016/j.gde.2021.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/06/2021] [Accepted: 08/12/2021] [Indexed: 12/16/2022]
Abstract
Many microsatellite DNA sequences are able to form non-B form DNA secondary structures, such as hairpin loops, cruciforms, triplex DNA or G-quadruplexes. These DNA structures can form a significant impediment to DNA replication and repair, leading to DNA nicks, gaps, and breaks, which can be repaired by homologous recombination (HR). Recent work understanding HR at structure-forming repeats has focused on genetic requirements for replication fork restart, break induced replication (BIR) at broken forks, recombination during and after relocalization of breaks or stalled forks to the nuclear periphery, and how repair pathway choice and kinetics are navigated in the presence of a repeat tract. In this review, we summarize recent developments that illuminate the role of recombination in repairing DNA damage or causing tract length changes within repetitive DNA and its role in maintaining genome stability.
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Affiliation(s)
- Erica J Polleys
- Department of Biology, Tufts University, Medford MA 02155, United States
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Medford MA 02155, United States; Program in Genetics, Tufts University, Boston MA 02111, United States.
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Narayanan A, Vadnala RN, Ganguly P, Selvakumar P, Rudramurthy SM, Prasad R, Chakrabarti A, Siddharthan R, Sanyal K. Functional and Comparative Analysis of Centromeres Reveals Clade-Specific Genome Rearrangements in Candida auris and a Chromosome Number Change in Related Species. mBio 2021; 12:e00905-21. [PMID: 33975937 PMCID: PMC8262905 DOI: 10.1128/mbio.00905-21] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/22/2022] Open
Abstract
The thermotolerant multidrug-resistant ascomycete Candida auris rapidly emerged since 2009 causing systemic infections worldwide and simultaneously evolved in different geographical zones. The molecular events that orchestrated this sudden emergence of the killer fungus remain mostly elusive. Here, we identify centromeres in C. auris and related species, using a combined approach of chromatin immunoprecipitation and comparative genomic analyses. We find that C. auris and multiple other species in the Clavispora/Candida clade shared a conserved small regional GC-poor centromere landscape lacking pericentromeres or repeats. Further, a centromere inactivation event led to karyotypic alterations in this species complex. Interspecies genome analysis identified several structural chromosomal changes around centromeres. In addition, centromeres are found to be rapidly evolving loci among the different geographical clades of the same species of C. auris Finally, we reveal an evolutionary trajectory of the unique karyotype associated with clade 2 that consists of the drug-susceptible isolates of C. aurisIMPORTANCECandida auris, the killer fungus, emerged as different geographical clades, exhibiting multidrug resistance and high karyotype plasticity. Chromosomal rearrangements are known to play key roles in the emergence of new species, virulence, and drug resistance in pathogenic fungi. Centromeres, the genomic loci where microtubules attach to separate the sister chromatids during cell division, are known to be hot spots of breaks and downstream rearrangements. We identified the centromeres in C. auris and related species to study their involvement in the evolution and karyotype diversity reported in C. auris We report conserved centromere features in 10 related species and trace the events that occurred at the centromeres during evolution. We reveal a centromere inactivation-mediated chromosome number change in these closely related species. We also observe that one of the geographical clades, the East Asian clade, evolved along a unique trajectory, compared to the other clades and related species.
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Affiliation(s)
- Aswathy Narayanan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Rakesh Netha Vadnala
- Computational Biology, The Institute of Mathematical Sciences/HBNI, Chennai, India
| | - Promit Ganguly
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Pavitra Selvakumar
- Computational Biology, The Institute of Mathematical Sciences/HBNI, Chennai, India
| | - Shivaprakash M Rudramurthy
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rajendra Prasad
- Amity Institute of Biotechnology, Amity University Haryana, Haryana, India
| | - Arunaloke Chakrabarti
- Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Rahul Siddharthan
- Computational Biology, The Institute of Mathematical Sciences/HBNI, Chennai, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- Osaka University, Suita, Japan
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27
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Li S, Wang H, Jehi S, Li J, Liu S, Wang Z, Truong L, Chiba T, Wang Z, Wu X. PIF1 helicase promotes break-induced replication in mammalian cells. EMBO J 2021; 40:e104509. [PMID: 33470420 PMCID: PMC8047440 DOI: 10.15252/embj.2020104509] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 12/01/2020] [Accepted: 12/10/2020] [Indexed: 12/20/2022] Open
Abstract
Break‐induced replication (BIR) is a specialized homologous‐recombination pathway for DNA double‐strand break (DSB) repair, which often induces genome instability. In this study, we establish EGFP‐based recombination reporters to systematically study BIR in mammalian cells and demonstrate an important role of human PIF1 helicase in promoting BIR. We show that at endonuclease cleavage sites, PIF1‐dependent BIR is used for homology‐initiated recombination requiring long track DNA synthesis, but not short track gene conversion (STGC). We also show that structure formation‐prone AT‐rich DNA sequences derived from common fragile sites (CFS‐ATs) induce BIR upon replication stress and oncogenic stress, and PCNA‐dependent loading of PIF1 onto collapsed/broken forks is critical for BIR activation. At broken replication forks, even STGC‐mediated repair of double‐ended DSBs depends on POLD3 and PIF1, revealing an unexpected mechanism of BIR activation upon replication stress that differs from the conventional BIR activation model requiring DSB end sensing at endonuclease‐generated breaks. Furthermore, loss of PIF1 is synthetically lethal with loss of FANCM, which is involved in protecting CFS‐ATs. The breast cancer‐associated PIF1 mutant L319P is defective in BIR, suggesting a direct link of BIR to oncogenic processes.
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Affiliation(s)
- Shibo Li
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Hailong Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Sanaa Jehi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jun Li
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Shuo Liu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Zi Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.,Biomedical Gerontology Laboratory, Department of Health Science and Social Welfare, School of Human Sciences, Waseda University, Tokorozawa, Japan
| | - Lan Truong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Takuya Chiba
- Biomedical Gerontology Laboratory, Department of Health Science and Social Welfare, School of Human Sciences, Waseda University, Tokorozawa, Japan
| | - Zefeng Wang
- CAS Key Laboratory of Computational Biology, University of Chinese Academy of Sciences, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
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28
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Alternative DNA Structures In Vivo: Molecular Evidence and Remaining Questions. Microbiol Mol Biol Rev 2020; 85:85/1/e00110-20. [PMID: 33361270 DOI: 10.1128/mmbr.00110-20] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Duplex DNA naturally folds into a right-handed double helix in physiological conditions. Some sequences of unusual base composition may nevertheless form alternative structures, as was shown for many repeated sequences in vitro However, evidence for the formation of noncanonical structures in living cells is difficult to gather. It mainly relies on genetic assays demonstrating their function in vivo or through genetic instability reflecting particular properties of such structures. Efforts were made to reveal their existence directly in a living cell, mainly by generating antibodies specific to secondary structures or using chemical ligands selected for their affinity to these structures. Among secondary structure-forming DNAs are G-quadruplexes, human fragile sites containing minisatellites, AT-rich regions, inverted repeats able to form cruciform structures, hairpin-forming CAG/CTG triplet repeats, and triple helices formed by homopurine-homopyrimidine GAA/TTC trinucleotide repeats. Many of these alternative structures are involved in human pathologies, such as neurological or developmental disorders, as in the case of trinucleotide repeats, or cancers triggered by translocations linked to fragile sites. This review will discuss and highlight evidence supporting the formation of alternative DNA structures in vivo and will emphasize the role of the mismatch repair machinery in binding mispaired DNA duplexes, triggering genetic instability.
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29
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Brown RE, Freudenreich CH. Structure-forming repeats and their impact on genome stability. Curr Opin Genet Dev 2020; 67:41-51. [PMID: 33279816 DOI: 10.1016/j.gde.2020.10.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 10/22/2020] [Accepted: 10/24/2020] [Indexed: 12/12/2022]
Abstract
Repetitive sequences throughout the genome are a major source of endogenous DNA damage, due to the propensity of many of them to form alternative non-B DNA structures that can interfere with replication, transcription, and DNA repair. These repetitive sequences are prone to breakage (fragility) and instability (changes in repeat number). Repeat fragility and expansions are linked to several diseases, including many cancers and neurodegenerative diseases, hence the importance of understanding the mechanisms that cause genome instability and contribute to these diseases. This review focuses on recent findings of mechanisms causing repeat fragility and instability, new associations between repeat expansions and genetic diseases, and potential therapeutic options to target repeat expansions.
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Affiliation(s)
- Rebecca E Brown
- Program in Genetics, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Medford, MA 02155, USA; Program in Genetics, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA.
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30
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Pentzold C, Kokal M, Pentzold S, Weise A. Sites of chromosomal instability in the context of nuclear architecture and function. Cell Mol Life Sci 2020; 78:2095-2103. [PMID: 33219838 PMCID: PMC7966619 DOI: 10.1007/s00018-020-03698-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/02/2020] [Accepted: 10/31/2020] [Indexed: 12/13/2022]
Abstract
Chromosomal fragile sites are described as areas within the tightly packed mitotic chromatin that appear as breaks or gaps mostly tracing back to a loosened structure and not a real nicked break within the DNA molecule. Most facts about fragile sites result from studies in mitotic cells, mainly during metaphase and mainly in lymphocytes. Here, we synthesize facts about the genomic regions that are prone to form gaps and breaks on metaphase chromosomes in the context of interphase. We conclude that nuclear architecture shapes the activity profile of the cell, i.e. replication timing and transcriptional activity, thereby influencing genomic integrity during interphase with the potential to cause fragility in mitosis. We further propose fragile sites as examples of regions specifically positioned in the interphase nucleus with putative anchoring points at the nuclear lamina to enable a tightly regulated replication–transcription profile and diverse signalling functions in the cell. Consequently, fragility starts before the actual display as chromosomal breakage in metaphase to balance the initial contradiction of cellular overgrowth or malfunctioning and maintaining diversity in molecular evolution.
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Affiliation(s)
- Constanze Pentzold
- Institute of Human Genetics, University Hospital, Friedrich Schiller University Jena, 07747, Jena, Germany.
| | - Miriam Kokal
- Institute of Human Genetics, University Hospital, Friedrich Schiller University Jena, 07747, Jena, Germany
| | - Stefan Pentzold
- Research Center Lobeda, Jena University Hospital, 07747, Jena, Germany
| | - Anja Weise
- Institute of Human Genetics, University Hospital, Friedrich Schiller University Jena, 07747, Jena, Germany
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31
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Abstract
Mutation of the human genome results in three classes of genomic variation: single nucleotide variants; short insertions or deletions; and large structural variants (SVs). Some mutations occur during normal processes, such as meiotic recombination or B cell development, and others result from DNA replication or aberrant repair of breaks in sequence-specific contexts. Regardless of mechanism, mutations are subject to selection, and some hotspots can manifest in disease. Here, we discuss genomic regions prone to mutation, mechanisms contributing to mutation susceptibility, and the processes leading to their accumulation in normal and somatic genomes. With further, more accurate human genome sequencing, additional mutation hotspots, mechanistic details of their formation, and the relevance of hotspots to evolution and disease are likely to be discovered.
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32
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Macheret M, Bhowmick R, Sobkowiak K, Padayachy L, Mailler J, Hickson ID, Halazonetis TD. High-resolution mapping of mitotic DNA synthesis regions and common fragile sites in the human genome through direct sequencing. Cell Res 2020; 30:997-1008. [PMID: 32561860 PMCID: PMC7784693 DOI: 10.1038/s41422-020-0358-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 05/31/2020] [Indexed: 12/22/2022] Open
Abstract
DNA replication stress, a feature of human cancers, often leads to instability at specific genomic loci, such as the common fragile sites (CFSs). Cells experiencing DNA replication stress may also exhibit mitotic DNA synthesis (MiDAS). To understand the physiological function of MiDAS and its relationship to CFSs, we mapped, at high resolution, the genomic sites of MiDAS in cells treated with the DNA polymerase inhibitor aphidicolin. Sites of MiDAS were evident as well-defined peaks that were largely conserved between cell lines and encompassed all known CFSs. The MiDAS peaks mapped within large, transcribed, origin-poor genomic regions. In cells that had been treated with aphidicolin, these regions remained unreplicated even in late S phase; MiDAS then served to complete their replication after the cells entered mitosis. Interestingly, leading and lagging strand synthesis were uncoupled in MiDAS, consistent with MiDAS being a form of break-induced replication, a repair mechanism for collapsed DNA replication forks. Our results provide a better understanding of the mechanisms leading to genomic instability at CFSs and in cancer cells.
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Affiliation(s)
- Morgane Macheret
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Rahul Bhowmick
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Katarzyna Sobkowiak
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Laura Padayachy
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Jonathan Mailler
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark.
| | - Thanos D Halazonetis
- Department of Molecular Biology, University of Geneva, 1205, Geneva, Switzerland.
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33
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Li X, Pei Y, Zhang Y, Liu Y, Fu W, Li J, You H, Huang J. Single-Molecule Mechanical Unfolding of AT-Rich Chromosomal Fragile Site DNA Hairpins: Resolving the Thermodynamic and Kinetic Effects of a Single G-T Mismatch. J Phys Chem B 2020; 124:9365-9370. [PMID: 32970435 DOI: 10.1021/acs.jpcb.0c06954] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Chromosomal fragile sites (CFSs) contain AT-rich sequences that tend to form hairpins on lagging strands in DNA replication, making them hotspots for chromosomal rearrangements in cancers. Here, we investigate the structural stability of the AT-rich CFS DNA hairpins with a single non-AT base pair using magnetic tweezers. Strikingly, a single G-T mismatched base pair in the short CFS DNA hairpin gives a 38.7% reduction of the unfolding Gibbs free energy and a 100-fold increase of the transition kinetics compared to a single G-C matched base pair, which are deviated from the theoretical simulations. Our study reveals the unique features of CFSs to provide profound insights into chromosomal instability and structure-specific genome targeting therapeutics for genetic disorder-related diseases.
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Affiliation(s)
- Xiong Li
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yufeng Pei
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yashuo Zhang
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yajun Liu
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wenhao Fu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Jixi Li
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Huijuan You
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jinqing Huang
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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34
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Szlachta K, Manukyan A, Raimer HM, Singh S, Salamon A, Guo W, Lobachev KS, Wang YH. Topoisomerase II contributes to DNA secondary structure-mediated double-stranded breaks. Nucleic Acids Res 2020; 48:6654-6671. [PMID: 32501506 PMCID: PMC7337936 DOI: 10.1093/nar/gkaa483] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/20/2020] [Accepted: 06/01/2020] [Indexed: 12/12/2022] Open
Abstract
DNA double-stranded breaks (DSBs) trigger human genome instability, therefore identifying what factors contribute to DSB induction is critical for our understanding of human disease etiology. Using an unbiased, genome-wide approach, we found that genomic regions with the ability to form highly stable DNA secondary structures are enriched for endogenous DSBs in human cells. Human genomic regions predicted to form non-B-form DNA induced gross chromosomal rearrangements in yeast and displayed high indel frequency in human genomes. The extent of instability in both analyses is in concordance with the structure forming ability of these regions. We also observed an enrichment of DNA secondary structure-prone sites overlapping transcription start sites (TSSs) and CCCTC-binding factor (CTCF) binding sites, and uncovered an increase in DSBs at highly stable DNA secondary structure regions, in response to etoposide, an inhibitor of topoisomerase II (TOP2) re-ligation activity. Importantly, we found that TOP2 deficiency in both yeast and human leads to a significant reduction in DSBs at structure-prone loci, and that sites of TOP2 cleavage have a greater ability to form highly stable DNA secondary structures. This study reveals a direct role for TOP2 in generating secondary structure-mediated DNA fragility, advancing our understanding of mechanisms underlying human genome instability.
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Affiliation(s)
- Karol Szlachta
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Arkadi Manukyan
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Heather M Raimer
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Sandeep Singh
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Anita Salamon
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
| | - Wenying Guo
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Kirill S Lobachev
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908-0733, USA
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35
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Gadgil RY, Romer EJ, Goodman CC, Rider SD, Damewood FJ, Barthelemy JR, Shin-Ya K, Hanenberg H, Leffak M. Replication stress at microsatellites causes DNA double-strand breaks and break-induced replication. J Biol Chem 2020; 295:15378-15397. [PMID: 32873711 DOI: 10.1074/jbc.ra120.013495] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/23/2020] [Indexed: 12/12/2022] Open
Abstract
Short tandemly repeated DNA sequences, termed microsatellites, are abundant in the human genome. These microsatellites exhibit length instability and susceptibility to DNA double-strand breaks (DSBs) due to their tendency to form stable non-B DNA structures. Replication-dependent microsatellite DSBs are linked to genome instability signatures in human developmental diseases and cancers. To probe the causes and consequences of microsatellite DSBs, we designed a dual-fluorescence reporter system to detect DSBs at expanded (CTG/CAG) n and polypurine/polypyrimidine (Pu/Py) mirror repeat structures alongside the c-myc replication origin integrated at a single ectopic chromosomal site. Restriction cleavage near the (CTG/CAG)100 microsatellite leads to homology-directed single-strand annealing between flanking AluY elements and reporter gene deletion that can be detected by flow cytometry. However, in the absence of restriction cleavage, endogenous and exogenous replication stressors induce DSBs at the (CTG/CAG)100 and Pu/Py microsatellites. DSBs map to a narrow region at the downstream edge of the (CTG)100 lagging-strand template. (CTG/CAG) n chromosome fragility is repeat length-dependent, whereas instability at the (Pu/Py) microsatellites depends on replication polarity. Strikingly, restriction-generated DSBs and replication-dependent DSBs are not repaired by the same mechanism. Knockdown of DNA damage response proteins increases (Rad18, polymerase (Pol) η, Pol κ) or decreases (Mus81) the sensitivity of the (CTG/CAG)100 microsatellites to replication stress. Replication stress and DSBs at the ectopic (CTG/CAG)100 microsatellite lead to break-induced replication and high-frequency mutagenesis at a flanking thymidine kinase gene. Our results show that non-B structure-prone microsatellites are susceptible to replication-dependent DSBs that cause genome instability.
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Affiliation(s)
- Rujuta Yashodhan Gadgil
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Eric J Romer
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Caitlin C Goodman
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - S Dean Rider
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - French J Damewood
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Joanna R Barthelemy
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Kazuo Shin-Ya
- Biomedical Information Research Center, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Helmut Hanenberg
- Department of Otorhinolaryngology and Head/Neck Surgery, Heinrich Heine University, Düsseldorf, Germany; Department of Pediatrics III, University Children's Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Michael Leffak
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA.
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36
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Ji F, Liao H, Pan S, Ouyang L, Jia F, Fu Z, Zhang F, Geng X, Wang X, Li T, Liu S, Syeda MZ, Chen H, Li W, Chen Z, Shen H, Ying S. Genome-wide high-resolution mapping of mitotic DNA synthesis sites and common fragile sites by direct sequencing. Cell Res 2020; 30:1009-1023. [PMID: 32561861 DOI: 10.1038/s41422-020-0357-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 05/31/2020] [Indexed: 01/13/2023] Open
Abstract
Common fragile sites (CFSs) are genomic loci prone to the formation of breaks or gaps on metaphase chromosomes. They are hotspots for chromosome rearrangements and structural variations, which have been extensively implicated in carcinogenesis, aging, and other pathological processes. Although many CFSs were identified decades ago, a consensus is still lacking for why they are particularly unstable and sensitive to replication perturbations. This is in part due to the lack of high-resolution mapping data for the vast majority of the CFSs, which has hindered mechanistic interrogations. Here, we seek to map human CFSs with high resolution on a genome-wide scale by sequencing the sites of mitotic DNA synthesis (MiDASeq) that are specific for CFSs. We generated a nucleotide-resolution atlas of MiDAS sites (MDSs) that covered most of the known CFSs, and comprehensively analyzed their sequence characteristics and genomic features. Our data on MDSs tallied well with long-standing hypotheses to explain CFS fragility while highlighting the contributions of late replication timing and large transcription units. Notably, the MDSs also encompassed most of the recurrent double-strand break clusters previously identified in mouse neural stem/progenitor cells, thus bridging evolutionarily conserved break points across species. Moreover, MiDAseq provides an important resource that can stimulate future research on CFSs to further unravel the mechanisms and biological relevance underlying these labile genomic regions.
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Affiliation(s)
- Fang Ji
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Hongwei Liao
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Sheng Pan
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.,Chu Kochen Honors College of Zhejiang University, Hangzhou, Zhejiang, China
| | - Liujian Ouyang
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.,Chu Kochen Honors College of Zhejiang University, Hangzhou, Zhejiang, China
| | - Fang Jia
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.,Chu Kochen Honors College of Zhejiang University, Hangzhou, Zhejiang, China
| | - Zaiyang Fu
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.,Chu Kochen Honors College of Zhejiang University, Hangzhou, Zhejiang, China
| | - Fengjiao Zhang
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Xinwei Geng
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Xinming Wang
- School of Life Sciences, Peking University, Beijing, 100871, China
| | - Tingting Li
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Shuangying Liu
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.,Chu Kochen Honors College of Zhejiang University, Hangzhou, Zhejiang, China
| | - Madiha Zahra Syeda
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China
| | - Haixia Chen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China
| | - Wen Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China
| | - Zhihua Chen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China
| | - Huahao Shen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310009, China. .,State Key Laboratory of Respiratory Diseases, Guangzhou, Guangdong, 510120, China.
| | - Songmin Ying
- Department of Pharmacology & Department of Respiratory and Critical Care Medicine of the Second Affiliated Hospital, Zhejiang University School of Medicine, Key Laboratory of Respiratory Disease of Zhejiang Province, Hangzhou, Zhejiang, 310009, China.
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37
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Kaushal S, Wollmuth CE, Das K, Hile SE, Regan SB, Barnes RP, Haouzi A, Lee SM, House NCM, Guyumdzhyan M, Eckert KA, Freudenreich CH. Sequence and Nuclease Requirements for Breakage and Healing of a Structure-Forming (AT)n Sequence within Fragile Site FRA16D. Cell Rep 2020; 27:1151-1164.e5. [PMID: 31018130 DOI: 10.1016/j.celrep.2019.03.103] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 02/07/2019] [Accepted: 03/27/2019] [Indexed: 01/20/2023] Open
Abstract
Common fragile sites (CFSs) are genomic regions that display gaps and breaks in human metaphase chromosomes under replication stress and are often deleted in cancer cells. We studied an ∼300-bp subregion (Flex1) of human CFS FRA16D in yeast and found that it recapitulates characteristics of CFS fragility in human cells. Flex1 fragility is dependent on the ability of a variable-length AT repeat to form a cruciform structure that stalls replication. Fragility at Flex1 is initiated by structure-specific endonuclease Mus81-Mms4 acting together with the Slx1-4/Rad1-10 complex, whereas Yen1 protects Flex1 against breakage. Sae2 is required for healing of Flex1 after breakage. Our study shows that breakage within a CFS can be initiated by nuclease cleavage at forks stalled at DNA structures. Furthermore, our results suggest that CFSs are not just prone to breakage but also are impaired in their ability to heal, and this deleterious combination accounts for their fragility.
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Affiliation(s)
- Simran Kaushal
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Charles E Wollmuth
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Kohal Das
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Suzanne E Hile
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Samantha B Regan
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Ryan P Barnes
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Alice Haouzi
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Soo Mi Lee
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Nealia C M House
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Michael Guyumdzhyan
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA
| | - Kristin A Eckert
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Suite 4700, 200 Boston Ave., Medford, MA 02155, USA; Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA 02111, USA.
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38
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Abstract
Common fragile sites (CFSs) are large chromosomal regions that exhibit breakage on metaphase chromosomes upon replication stress. They become preferentially unstable at the early stage of cancer development and are hotspots for chromosomal rearrangements in cancers. Increasing evidence has highlighted the complexity underlying the instability of CFSs, and a combination of multiple mechanisms is believed to cause CFS fragility. We will review recent advancements in our understanding of the molecular mechanisms underlying the maintenance of CFS stability and the relevance of CFSs to cancer-associated genome instability. We will emphasize the contribution of the structure-prone AT-rich sequences to CFS instability, which is in line with the recent genome-wide study showing that structure-forming repeat sequences are principal sites of replication stress.
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Affiliation(s)
- Shibo Li
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, San Diego, CA 92037 USA
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, San Diego, CA 92037 USA
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39
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From R-Loops to G-Quadruplexes: Emerging New Threats for the Replication Fork. Int J Mol Sci 2020; 21:ijms21041506. [PMID: 32098397 PMCID: PMC7073102 DOI: 10.3390/ijms21041506] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/14/2020] [Accepted: 02/20/2020] [Indexed: 12/12/2022] Open
Abstract
Replicating the entire genome is one of the most complex tasks for all organisms. Research carried out in the last few years has provided us with a clearer picture on how cells preserve genomic information from the numerous insults that may endanger its stability. Different DNA repair pathways, coping with exogenous or endogenous threat, have been dissected at the molecular level. More recently, there has been an increasing interest towards intrinsic obstacles to genome replication, paving the way to a novel view on genomic stability. Indeed, in some cases, the movement of the replication fork can be hindered by the presence of stable DNA: RNA hybrids (R-loops), the folding of G-rich sequences into G-quadruplex structures (G4s) or repetitive elements present at Common Fragile Sites (CFS). Although differing in their nature and in the way they affect the replication fork, all of these obstacles are a source of replication stress. Replication stress is one of the main hallmarks of cancer and its prevention is becoming increasingly important as a target for future chemotherapeutics. Here we will try to summarize how these three obstacles are generated and how the cells handle replication stress upon their encounter. Finally, we will consider their role in cancer and their exploitation in current chemotherapeutic approaches.
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40
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Sankaranarayanan SR, Ianiri G, Coelho MA, Reza MH, Thimmappa BC, Ganguly P, Vadnala RN, Sun S, Siddharthan R, Tellgren-Roth C, Dawson TL, Heitman J, Sanyal K. Loss of centromere function drives karyotype evolution in closely related Malassezia species. eLife 2020; 9:e53944. [PMID: 31958060 PMCID: PMC7025860 DOI: 10.7554/elife.53944] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/20/2020] [Indexed: 12/14/2022] Open
Abstract
Genomic rearrangements associated with speciation often result in variation in chromosome number among closely related species. Malassezia species show variable karyotypes ranging between six and nine chromosomes. Here, we experimentally identified all eight centromeres in M. sympodialis as 3-5-kb long kinetochore-bound regions that span an AT-rich core and are depleted of the canonical histone H3. Centromeres of similar sequence features were identified as CENP-A-rich regions in Malassezia furfur, which has seven chromosomes, and histone H3 depleted regions in Malassezia slooffiae and Malassezia globosa with nine chromosomes each. Analysis of synteny conservation across centromeres with newly generated chromosome-level genome assemblies suggests two distinct mechanisms of chromosome number reduction from an inferred nine-chromosome ancestral state: (a) chromosome breakage followed by loss of centromere DNA and (b) centromere inactivation accompanied by changes in DNA sequence following chromosome-chromosome fusion. We propose that AT-rich centromeres drive karyotype diversity in the Malassezia species complex through breakage and inactivation.
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Affiliation(s)
- Sundar Ram Sankaranarayanan
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Giuseppe Ianiri
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Marco A Coelho
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Md Hashim Reza
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Bhagya C Thimmappa
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | - Promit Ganguly
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
| | | | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | | | - Christian Tellgren-Roth
- National Genomics Infrastructure, Science for Life Laboratory, Department of Immunology, Genetics and Pathology, Uppsala UniversityUppsalaSweden
| | - Thomas L Dawson
- Skin Research Institute Singapore, Agency for Science, Technology and Research (A*STAR)SingaporeSingapore
- Department of Drug Discovery, Medical University of South Carolina, School of PharmacyCharlestonUnited States
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurhamUnited States
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific ResearchBengaluruIndia
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41
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Polleys EJ, Freudenreich CH. Genetic Assays to Study Repeat Fragility in Saccharomyces cerevisiae. Methods Mol Biol 2020; 2056:83-101. [PMID: 31586342 DOI: 10.1007/978-1-4939-9784-8_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Trinucleotide repeats are common in the human genome and can undergo changes in repeat number and cause length-dependent chromosome fragility. Expanded CAG repeats have been linked to over 14 human diseases and are considered hotspots for breakage and genomic rearrangement. Here we describe two Saccharomyces cerevisiae based assays that evaluate the rate of chromosome breakage that occurs within a repeat tract (fragility), with variations that allow the role of transcription to be evaluated. The first fragility assay utilizes end-loss and subsequent telomere addition as the main mode of repair of a yeast artificial chromosome (YAC). The second fragility assay relies on the fact that a chromosomal break stimulates recombination-mediated repair. A PCR-based assay can be used to evaluate instability of the repeat in the same conditions used to measure repeat fragility. These assays have contributed to understanding the genetic mechanisms that cause chromosome breaks and tract-length changes at unstable trinucleotide repeats.
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42
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Irony-Tur Sinai M, Salamon A, Stanleigh N, Goldberg T, Weiss A, Wang YH, Kerem B. AT-dinucleotide rich sequences drive fragile site formation. Nucleic Acids Res 2019; 47:9685-9695. [PMID: 31410468 PMCID: PMC6765107 DOI: 10.1093/nar/gkz689] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 07/18/2019] [Accepted: 08/04/2019] [Indexed: 12/29/2022] Open
Abstract
Common fragile sites (CFSs) are genomic regions prone to breakage under replication stress conditions recurrently rearranged in cancer. Many CFSs are enriched with AT-dinucleotide rich sequences (AT-DRSs) which have the potential to form stable secondary structures upon unwinding the double helix during DNA replication. These stable structures can potentially perturb DNA replication progression, leading to genomic instability. Using site-specific targeting system, we show that targeted integration of a 3.4 kb AT-DRS derived from the human CFS FRA16C into a chromosomally stable region within the human genome is able to drive fragile site formation under conditions of replication stress. Analysis of >1300 X chromosomes integrated with the 3.4 kb AT-DRS revealed recurrent gaps and breaks at the integration site. DNA sequences derived from the integrated AT-DRS showed in vitro a significantly increased tendency to fold into branched secondary structures, supporting the predicted mechanism of instability. Our findings clearly indicate that intrinsic DNA features, such as complexed repeated sequence motifs, predispose the human genome to chromosomal instability.
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Affiliation(s)
- Michal Irony-Tur Sinai
- Department of Genetics, The Life Sciences Institute, The Hebrew University of Jerusalem, 9190401, Israel
| | - Anita Salamon
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 229080733, USA
| | - Noemie Stanleigh
- Department of Genetics, The Life Sciences Institute, The Hebrew University of Jerusalem, 9190401, Israel
| | - Tchelet Goldberg
- Department of Genetics, The Life Sciences Institute, The Hebrew University of Jerusalem, 9190401, Israel
| | - Aryeh Weiss
- Faculty of Engineering, Bar-Ilan University, Ramat-Gan, 52900, Israel
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, 229080733, USA
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University of Jerusalem, 9190401, Israel
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43
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Replication Stress Response Links RAD52 to Protecting Common Fragile Sites. Cancers (Basel) 2019; 11:cancers11101467. [PMID: 31569559 PMCID: PMC6826974 DOI: 10.3390/cancers11101467] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 09/20/2019] [Accepted: 09/23/2019] [Indexed: 12/20/2022] Open
Abstract
Rad52 in yeast is a key player in homologous recombination (HR), but mammalian RAD52 is dispensable for HR as shown by the lack of a strong HR phenotype in RAD52-deficient cells and in RAD52 knockout mice. RAD52 function in mammalian cells first emerged with the discovery of its important backup role to BRCA (breast cancer genes) in HR. Recent new evidence further demonstrates that RAD52 possesses multiple activities to cope with replication stress. For example, replication stress-induced DNA repair synthesis in mitosis (MiDAS) and oncogene overexpression-induced DNA replication are dependent on RAD52. RAD52 becomes essential in HR to repair DSBs containing secondary structures, which often arise at collapsed replication forks. RAD52 is also implicated in break-induced replication (BIR) and is found to inhibit excessive fork reversal at stalled replication forks. These various functions of RAD52 to deal with replication stress have been linked to the protection of genome stability at common fragile sites, which are often associated with the DNA breakpoints in cancer. Therefore, RAD52 has important recombination roles under special stress conditions in mammalian cells, and presents as a promising anti-cancer therapy target.
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44
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Bracewell R, Chatla K, Nalley MJ, Bachtrog D. Dynamic turnover of centromeres drives karyotype evolution in Drosophila. eLife 2019; 8:e49002. [PMID: 31524597 PMCID: PMC6795482 DOI: 10.7554/elife.49002] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/12/2019] [Indexed: 12/21/2022] Open
Abstract
Centromeres are the basic unit for chromosome inheritance, but their evolutionary dynamics is poorly understood. We generate high-quality reference genomes for multiple Drosophila obscura group species to reconstruct karyotype evolution. All chromosomes in this lineage were ancestrally telocentric and the creation of metacentric chromosomes in some species was driven by de novo seeding of new centromeres at ancestrally gene-rich regions, independently of chromosomal rearrangements. The emergence of centromeres resulted in a drastic size increase due to repeat accumulation, and dozens of genes previously located in euchromatin are now embedded in pericentromeric heterochromatin. Metacentric chromosomes secondarily became telocentric in the pseudoobscura subgroup through centromere repositioning and a pericentric inversion. The former (peri)centric sequences left behind shrunk dramatically in size after their inactivation, yet contain remnants of their evolutionary past, including increased repeat-content and heterochromatic environment. Centromere movements are accompanied by rapid turnover of the major satellite DNA detected in (peri)centromeric regions.
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Affiliation(s)
- Ryan Bracewell
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Kamalakar Chatla
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Matthew J Nalley
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Doris Bachtrog
- Department of Integrative BiologyUniversity of California, BerkeleyBerkeleyUnited States
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45
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Huckaby AC, Granum CS, Carey MA, Szlachta K, Al-Barghouthi B, Wang YH, Guler JL. Complex DNA structures trigger copy number variation across the Plasmodium falciparum genome. Nucleic Acids Res 2019; 47:1615-1627. [PMID: 30576466 PMCID: PMC6393310 DOI: 10.1093/nar/gky1268] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 12/04/2018] [Accepted: 12/07/2018] [Indexed: 02/06/2023] Open
Abstract
Antimalarial resistance is a major obstacle in the eradication of the human malaria parasite, Plasmodium falciparum. Genome amplifications, a type of DNA copy number variation (CNV), facilitate overexpression of drug targets and contribute to parasite survival. Long monomeric A/T tracks are found at the breakpoints of many Plasmodium resistance-conferring CNVs. We hypothesize that other proximal sequence features, such as DNA hairpins, act with A/T tracks to trigger CNV formation. By adapting a sequence analysis pipeline to investigate previously reported CNVs, we identified breakpoints in 35 parasite clones with near single base-pair resolution. Using parental genome sequence, we predicted the formation of stable hairpins within close proximity to all future breakpoint locations. Especially stable hairpins were predicted to form near five shared breakpoints, establishing that the initiating event could have occurred at these sites. Further in-depth analyses defined characteristics of these 'trigger sites' across the genome and detected signatures of error-prone repair pathways at the breakpoints. We propose that these two genomic signals form the initial lesion (hairpins) and facilitate microhomology-mediated repair (A/T tracks) that lead to CNV formation across this highly repetitive genome. Targeting these repair pathways in P. falciparum may be used to block adaptation to antimalarial drugs.
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Affiliation(s)
- Adam C Huckaby
- Department of Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Claire S Granum
- Department of Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Maureen A Carey
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908, USA.,Division of Infectious Diseases and International Health, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Karol Szlachta
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Basel Al-Barghouthi
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA.,Center for Public Health Genomics, University of Virginia, Charlottesville, VA 22908, USA
| | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia Health System, Charlottesville, VA 22908, USA
| | - Jennifer L Guler
- Department of Biology, University of Virginia, Charlottesville, VA 22908, USA.,Division of Infectious Diseases and International Health, University of Virginia Health System, Charlottesville, VA 22908, USA
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46
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Pentzold C, Shah SA, Hansen NR, Le Tallec B, Seguin-Orlando A, Debatisse M, Lisby M, Oestergaard VH. FANCD2 binding identifies conserved fragile sites at large transcribed genes in avian cells. Nucleic Acids Res 2019; 46:1280-1294. [PMID: 29253234 PMCID: PMC5815096 DOI: 10.1093/nar/gkx1260] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/05/2017] [Indexed: 12/14/2022] Open
Abstract
Common Chromosomal Fragile Sites (CFSs) are specific genomic regions prone to form breaks on metaphase chromosomes in response to replication stress. Moreover, CFSs are mutational hotspots in cancer genomes, showing that the mutational mechanisms that operate at CFSs are highly active in cancer cells. Orthologs of human CFSs are found in a number of other mammals, but the extent of CFS conservation beyond the mammalian lineage is unclear. Characterization of CFSs from distantly related organisms can provide new insight into the biology underlying CFSs. Here, we have mapped CFSs in an avian cell line. We find that, overall the most significant CFSs coincide with extremely large conserved genes, from which very long transcripts are produced. However, no significant correlation between any sequence characteristics and CFSs is found. Moreover, we identified putative early replicating fragile sites (ERFSs), which is a distinct class of fragile sites and we developed a fluctuation analysis revealing high mutation rates at the CFS gene PARK2, with deletions as the most prevalent mutation. Finally, we show that avian homologs of the human CFS genes despite their fragility have resisted the general intron size reduction observed in birds suggesting that CFSs have a conserved biological function.
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Affiliation(s)
- Constanze Pentzold
- Department of Biology; University of Copenhagen; Copenhagen N 2200, Denmark
| | - Shiraz Ali Shah
- Department of Biology; University of Copenhagen; Copenhagen N 2200, Denmark
| | - Niels Richard Hansen
- Department of Mathematical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Benoît Le Tallec
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), CNRS-UMR8197 - Inserm U1024, Paris F-75005, France
| | - Andaine Seguin-Orlando
- Center for GeoGenetics, Natural History Museum of Denmark; University of Copenhagen; Copenhagen 1350, Denmark.,Danish National High-throughput DNA Sequencing Centre, University of Copenhagen, Øster Farimagsgade 2D, Copenhagen K 1353, Denmark
| | | | - Michael Lisby
- Department of Biology; University of Copenhagen; Copenhagen N 2200, Denmark.,Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3b, DK-2200 Copenhagen N, Denmark
| | - Vibe H Oestergaard
- Department of Biology; University of Copenhagen; Copenhagen N 2200, Denmark
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47
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Li S, Lu H, Wang Z, Hu Q, Wang H, Xiang R, Chiba T, Wu X. ERCC1/XPF Is Important for Repair of DNA Double-Strand Breaks Containing Secondary Structures. iScience 2019; 16:63-78. [PMID: 31153042 PMCID: PMC6543133 DOI: 10.1016/j.isci.2019.05.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/02/2019] [Accepted: 05/10/2019] [Indexed: 12/15/2022] Open
Abstract
The structure-specific endonuclease ERCC1/XPF plays an important role in nucleotide excision repair and interstrand cross-link repair. In this study, we identified new functions of ERCC1/XPF in DNA double-strand break (DSB) repair. We found that the conserved function of ERCC1/XPF to remove non-homologous sequences at DSBs is a rate-limiting step for homologous recombination in mammalian cells, and more importantly, we uncovered an indispensable role of ERCC1/XPF in repair of DSBs containing DNA secondary structures, including the structure-prone AT-rich DNA sequences derived from common fragile sites and G-quadruplexes (G4s). We also demonstrated a synthetic lethal interaction of XPF with DNA translocase FANCM that is involved in removing DNA secondary structures. Furthermore, inactivation of XPF sensitizes FANCM-deficient cells to G4-interacting compounds. These results suggest an important function of ERCC1/XPF in protecting DNA secondary structures and provide a rationale for targeted treatment of FANCM-deficient tumors through inhibition of XPF.
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Affiliation(s)
- Shibo Li
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hongyan Lu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; School of Medicine, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Zi Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA; Biomedical Gerontology Laboratory, Department of Health Science and Social Welfare, School of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa 359-1192, Japan
| | - Qing Hu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hongjun Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Rong Xiang
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin 300071, China
| | - Takuya Chiba
- Biomedical Gerontology Laboratory, Department of Health Science and Social Welfare, School of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa 359-1192, Japan
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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RNA insertion in DNA as the imprint moiety: the fission yeast paradigm. Curr Genet 2019; 65:1301-1306. [PMID: 31076844 DOI: 10.1007/s00294-019-00991-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 10/26/2022]
Abstract
This review elaborates on the findings of a new report which possibly resolves the biochemical nature of a novel type of DNA imprint as ribonucleotide and the mechanism of its formation during cell differentiation in fission yeast. The process of mating-type switching in fission yeast, Schizosaccharomyces pombe, displays characteristics of a typical mammalian stem cell lineage, wherein a cell divides to produce an identical cell and a differentiated cell after every two cell divisions. This developmental asymmetry has been ascribed to play a role in generation of a DNA strand-specific imprint at the mat1 locus during lagging strand synthesis and its segregation to one of the two daughter cells by the process of asymmetric, semi-conservative DNA replication. The nature of this imprint and mechanisms of its generation have been a subject of research and debate. A recent report by Singh et al. (Nucleic Acids Res 47:3422-3433. https://doi.org/10.1093/nar/gkz092 , 2019) provides compelling evidence in support of a ribonucleotide as the imprint moiety within the mat1 DNA and demonstrates the role of Mcm10/Cdc23, an important, evolutionarily conserved component of DNA replication machinery in eukaryotes, in installing the imprint through a non-canonical primase activity and interaction with DNA Polα and Swi1. The high degree of conservation of DNA replication machinery, especially the presence of the T7 gene 4 helicase/primase domain in the mammalian orthologs of Mcm10 suggests that similar mechanisms of DNA imprinting may play a role during cell differentiation in metazoans.
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Gerbault-Seureau M, Fuchs J, Dutrillaux B. High BrdU Sensitivity of Passeriformes Chromosomes: Conservation of BrdU-Sensitive Fragile Sites on Their Z Chromosomes during Evolution. Cytogenet Genome Res 2019; 157:158-165. [PMID: 30974432 DOI: 10.1159/000499590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2018] [Indexed: 12/29/2022] Open
Abstract
Amongst 15 bird species, representative of 7 orders, recurrent breakages evocating the presence of fragile sites were detected in the chromosomes of the 5 species belonging to Passeriformes. These breaks appeared when 5-bromodeoxyuridine (BrdU) was added to the cell culture medium at a dose inefficient for inducing chromosome structure alterations in other birds and mammals. They involved, similarly in male and female, 3 loci on the Z chromosome of 3 Turdus species (Turdidae). Labeling by BrdU antibody confirmed the correlation between BrdU incorporation into DNA and breakage, especially around and in the sites of breakage. Thus, 3 BrdU-sensitive fragile sites were present in the Z chromosomes of these birds. Three fragile sites were also detected at different locations in the Z chromosomes of the European robin (Erithacus rubecula, Muscicapidae), suggesting that a structural rearrangement occurred during the evolution of Turdidae and Muscicapidae. Chromosome banding confirmed this interpretation. Finally, in the more distantly related species Parus major (Paridae), the almost acrocentric Z chromosome displayed a single BrdU-sensitive fragile site in its short arm, and the W appeared to be pulverized by BrdU incorporation. Although it cannot be excluded that the BrdU-sensitive fragile sites may be involved in rearrangements, their conservation in many species, and possibly all Passeriformes, provides evidence that they do not constitute a pejorative character during evolution.
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Kaushal S, Freudenreich CH. The role of fork stalling and DNA structures in causing chromosome fragility. Genes Chromosomes Cancer 2019; 58:270-283. [PMID: 30536896 DOI: 10.1002/gcc.22721] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/13/2018] [Accepted: 12/03/2018] [Indexed: 12/19/2022] Open
Abstract
Alternative non-B form DNA structures, also called secondary structures, can form in certain DNA sequences under conditions that produce single-stranded DNA, such as during replication, transcription, and repair. Direct links between secondary structure formation, replication fork stalling, and genomic instability have been found for many repeated DNA sequences that cause disease when they expand. Common fragile sites (CFSs) are known to be AT-rich and break under replication stress, yet the molecular basis for their fragility is still being investigated. Over the past several years, new evidence has linked both the formation of secondary structures and transcription to fork stalling and fragility of CFSs. How these two events may synergize to cause fragility and the role of nuclease cleavage at secondary structures in rare and CFSs are discussed here. We also highlight evidence for a new hypothesis that secondary structures at CFSs not only initiate fragility but also inhibit healing, resulting in their characteristic appearance.
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Affiliation(s)
- Simran Kaushal
- Department of Biology, Tufts University, Medford, Massachusetts
| | - Catherine H Freudenreich
- Department of Biology, Tufts University, Medford, Massachusetts.,Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, Massachusetts
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