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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: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [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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2
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Kodali S, Meyer-Nava S, Landry S, Chakraborty A, Rivera-Mulia JC, Feng W. Epigenomic signatures associated with spontaneous and replication stress-induced DNA double strand breaks. Front Genet 2022; 13:907547. [PMID: 36506300 PMCID: PMC9730818 DOI: 10.3389/fgene.2022.907547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 11/07/2022] [Indexed: 11/25/2022] Open
Abstract
Common fragile sites (CFSs) are specific regions of all individuals' genome that are predisposed to DNA double strand breaks (DSBs) and undergo subsequent rearrangements. CFS formation can be induced in vitro by mild level of DNA replication stress, such as DNA polymerase inhibition or nucleotide pool disturbance. The mechanisms of CFS formation have been linked to DNA replication timing control, transcription activities, as well as chromatin organization. However, it is unclear what specific cis- or trans-factors regulate the interplay between replication and transcription that determine CFS formation. We recently reported genome-wide mapping of DNA DSBs under replication stress induced by aphidicolin in human lymphoblastoids for the first time. Here, we systematically compared these DSBs with regards to nearby epigenomic features mapped in the same cell line from published studies. We demonstrate that aphidicolin-induced DSBs are strongly correlated with histone 3 lysine 36 trimethylation, a marker for active transcription. We further demonstrate that this DSB signature is a composite effect by the dual treatment of aphidicolin and its solvent, dimethylsulfoxide, the latter of which potently induces transcription on its own. We also present complementing evidence for the association between DSBs and 3D chromosome architectural domains with high density gene cluster and active transcription. Additionally, we show that while DSBs were detected at all but one of the fourteen finely mapped CFSs, they were not enriched in the CFS core sequences and rather demarcated the CFS core region. Related to this point, DSB density was not higher in large genes of greater than 300 kb, contrary to reported enrichment of CFS sites at these large genes. Finally, replication timing analyses demonstrate that the CFS core region contain initiation events, suggesting that altered replication dynamics are responsible for CFS formation in relatively higher level of replication stress.
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Affiliation(s)
- Sravan Kodali
- Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, NY, United States
| | - Silvia Meyer-Nava
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Stephen Landry
- Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, NY, United States
| | - Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, NY, United States
| | - Juan Carlos Rivera-Mulia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Wenyi Feng
- Department of Biochemistry and Molecular Biology, Upstate Medical University, Syracuse, NY, United States
- *Correspondence: Wenyi Feng,
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Courtot L, Bournique E, Maric C, Guitton-Sert L, Madrid-Mencía M, Pancaldi V, Cadoret JC, Hoffmann JS, Bergoglio V. Low Replicative Stress Triggers Cell-Type Specific Inheritable Advanced Replication Timing. Int J Mol Sci 2021; 22:ijms22094959. [PMID: 34066960 PMCID: PMC8125030 DOI: 10.3390/ijms22094959] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/30/2021] [Accepted: 05/02/2021] [Indexed: 12/27/2022] Open
Abstract
DNA replication timing (RT), reflecting the temporal order of origin activation, is known as a robust and conserved cell-type specific process. Upon low replication stress, the slowing of replication forks induces well-documented RT delays associated to genetic instability, but it can also generate RT advances that are still uncharacterized. In order to characterize these advanced initiation events, we monitored the whole genome RT from six independent human cell lines treated with low doses of aphidicolin. We report that RT advances are cell-type-specific and involve large heterochromatin domains. Importantly, we found that some major late to early RT advances can be inherited by the unstressed next-cellular generation, which is a unique process that correlates with enhanced chromatin accessibility, as well as modified replication origin landscape and gene expression in daughter cells. Collectively, this work highlights how low replication stress may impact cellular identity by RT advances events at a subset of chromosomal domains.
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Affiliation(s)
- Lilas Courtot
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Elodie Bournique
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Chrystelle Maric
- Université de Paris, CNRS, Institut Jacques Monod, DNA Replication Pathologies Team, F-75006 Paris, France;
| | - Laure Guitton-Sert
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Miguel Madrid-Mencía
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
| | - Vera Pancaldi
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
- Barcelona Supercomputing Center, 08034 Barcelona, Spain
| | - Jean-Charles Cadoret
- Université de Paris, CNRS, Institut Jacques Monod, DNA Replication Pathologies Team, F-75006 Paris, France;
- Correspondence: (J.-C.C.); (J.-S.H.); (V.B.)
| | - Jean-Sébastien Hoffmann
- Laboratoire de pathologie, Laboratoire d’excellence Toulouse Cancer, Institut Universitaire du Cancer-Toulouse, Oncopole, 1 Avenue Irène-Joliot-Curie, CEDEX, 31059 Toulouse, France
- Correspondence: (J.-C.C.); (J.-S.H.); (V.B.)
| | - Valérie Bergoglio
- Centre de Recherches en Cancérologie de Toulouse (CRCT), UMR1037 Inserm, University Paul Sabatier III, ERL5294 CNRS, 2 Avenue Hubert Curien, 31037 Toulouse, France; (L.C.); (E.B.); (L.G.-S.); (M.M.-M.); (V.P.)
- Correspondence: (J.-C.C.); (J.-S.H.); (V.B.)
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Davis L, Khoo KJ, Zhang Y, Maizels N. POLQ suppresses interhomolog recombination and loss of heterozygosity at targeted DNA breaks. Proc Natl Acad Sci U S A 2020; 117:22900-22909. [PMID: 32873648 PMCID: PMC7502765 DOI: 10.1073/pnas.2008073117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Interhomolog recombination (IHR) occurs spontaneously in somatic human cells at frequencies that are low but sufficient to ameliorate some genetic diseases caused by heterozygous mutations or autosomal dominant mutations. Here we demonstrate that DNA nicks or double-strand breaks (DSBs) targeted by CRISPR-Cas9 to both homologs can stimulate IHR and associated copy-neutral loss of heterozygosity (cnLOH) in human cells. The frequency of IHR is 10-fold lower at nicks than at DSBs, but cnLOH is evident in a greater fraction of recombinants. IHR at DSBs occurs predominantly via reciprocal end joining. At DSBs, depletion of POLQ caused a dramatic increase in IHR and in the fraction of recombinants exhibiting cnLOH, suggesting that POLQ promotes end joining in cis, which limits breaks available for recombination in trans These results define conditions that may produce cnLOH as a mutagenic signature in cancer and may, conversely, promote therapeutic correction of both compound heterozygous and dominant negative mutations associated with genetic disease.
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Affiliation(s)
- Luther Davis
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195
| | - Kevin J Khoo
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195
| | - Yinbo Zhang
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195
| | - Nancy Maizels
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195;
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195
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5
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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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Primo LMF, Teixeira LK. DNA replication stress: oncogenes in the spotlight. Genet Mol Biol 2019; 43:e20190138. [PMID: 31930281 PMCID: PMC7197996 DOI: 10.1590/1678-4685gmb-2019-0138] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/09/2019] [Indexed: 01/21/2023] Open
Abstract
Precise replication of genetic material is essential to maintain genome stability. DNA replication is a tightly regulated process that ensues faithful copies of DNA molecules to daughter cells during each cell cycle. Perturbation of DNA replication may compromise the transmission of genetic information, leading to DNA damage, mutations, and chromosomal rearrangements. DNA replication stress, also referred to as DNA replicative stress, is defined as the slowing or stalling of replication fork progression during DNA synthesis as a result of different insults. Oncogene activation, one hallmark of cancer, is able to disturb numerous cellular processes, including DNA replication. In fact, extensive work has indicated that oncogene-induced replication stress is an important source of genomic instability in human carcinogenesis. In this review, we focus on main oncogenes that induce DNA replication stress, such as RAS, MYC, Cyclin E, MDM2, and BCL-2 among others, and the molecular mechanisms by which these oncogenes interfere with normal DNA replication and promote genomic instability.
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Affiliation(s)
- Luiza M. F. Primo
- Group of Cell Cycle Control, Program of Immunology and Tumor
Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ,
Brazil
| | - Leonardo K. Teixeira
- Group of Cell Cycle Control, Program of Immunology and Tumor
Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ,
Brazil
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7
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Abstract
Precise replication of genetic material is essential to maintain genome stability. DNA replication is a tightly regulated process that ensues faithful copies of DNA molecules to daughter cells during each cell cycle. Perturbation of DNA replication may compromise the transmission of genetic information, leading to DNA damage, mutations, and chromosomal rearrangements. DNA replication stress, also referred to as DNA replicative stress, is defined as the slowing or stalling of replication fork progression during DNA synthesis as a result of different insults. Oncogene activation, one hallmark of cancer, is able to disturb numerous cellular processes, including DNA replication. In fact, extensive work has indicated that oncogene-induced replication stress is an important source of genomic instability in human carcinogenesis. In this review, we focus on main oncogenes that induce DNA replication stress, such as RAS, MYC, Cyclin E, MDM2, and BCL-2 among others, and the molecular mechanisms by which these oncogenes interfere with normal DNA replication and promote genomic instability.
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Affiliation(s)
- Luiza M F Primo
- Group of Cell Cycle Control, Program of Immunology and Tumor Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ, Brazil
| | - Leonardo K Teixeira
- Group of Cell Cycle Control, Program of Immunology and Tumor Biology. Brazilian National Cancer Institute (INCA), Rio de Janeiro, RJ, Brazil
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8
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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: 25] [Impact Index Per Article: 5.0] [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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Guadarrama-Ponce R, Aranda-Anzaldo A. The epicenter of chromosomal fragility of Fra14A2, the mouse ortholog of human FRA3B common fragile site, is largely attached to the nuclear matrix in lymphocytes but not in other cell types that do not express such a fragility. J Cell Biochem 2019; 121:2209-2224. [PMID: 31646677 DOI: 10.1002/jcb.29444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/10/2019] [Indexed: 12/22/2022]
Abstract
Common fragile sites (CFSs) correspond to chromosomal regions susceptible to present breaks, discontinuities or constrictions in metaphase chromosomes from cells subjected to replication stress. They are considered as genomic regions intrinsically difficult to replicate and they are evolutionary conserved at least in mammals. However, the recent discovery that CFSs are cell-type specific indicates that DNA sequence by itself cannot account for CFS instability. Nevertheless, the large gene FHIT that includes FRA3B, the most highly expressed CFS in human lymphocytes, is commonly deleted in a variety of tumors suggesting a tumor suppressor role for its product. Here, we report that the epicenter of fragility of Fra14A2/Fhit, the mouse ortholog of human FRA3B/FHIT that like its human counterpart is the most highly expressed CFS in mouse lymphocytes, is largely attached to the nuclear matrix compartment in naive B lymphocytes but not in primary hepatocytes or cortical neurons that do not express such a CFS. Our results suggest a structural explanation for the difficult-to-replicate nature of such a region and so for its common fragility in lymphocytes, that is independent of the possible tumor suppressor role of the gene harboring such CFS.
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Affiliation(s)
- Rolando Guadarrama-Ponce
- Laboratorio de Biología Molecular y Neurociencias, Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, Mexico
| | - Armando Aranda-Anzaldo
- Laboratorio de Biología Molecular y Neurociencias, Facultad de Medicina, Universidad Autónoma del Estado de México, Toluca, Mexico
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Attwood SW, Edel MJ. iPS-Cell Technology and the Problem of Genetic Instability-Can It Ever Be Safe for Clinical Use? J Clin Med 2019; 8:jcm8030288. [PMID: 30823421 PMCID: PMC6462964 DOI: 10.3390/jcm8030288] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 02/23/2019] [Accepted: 02/25/2019] [Indexed: 12/20/2022] Open
Abstract
The use of induced Pluripotent Stem Cells (iPSC) as a source of autologous tissues shows great promise in regenerative medicine. Nevertheless, several major challenges remain to be addressed before iPSC-derived cells can be used in therapy, and experience of their clinical use is extremely limited. In this review, the factors affecting the safe translation of iPSC to the clinic are considered, together with an account of efforts being made to overcome these issues. The review draws upon experiences with pluripotent stem-cell therapeutics, including clinical trials involving human embryonic stem cells and the widely transplanted mesenchymal stem cells. The discussion covers concerns relating to: (i) the reprogramming process; (ii) the detection and removal of incompletely differentiated and pluripotent cells from the resulting medicinal products; and (iii) genomic and epigenetic changes, and the evolutionary and selective processes occurring during culture expansion, associated with production of iPSC-therapeutics. In addition, (iv) methods for the practical culture-at-scale and standardization required for routine clinical use are considered. Finally, (v) the potential of iPSC in the treatment of human disease is evaluated in the light of what is known about the reprogramming process, the behavior of cells in culture, and the performance of iPSC in pre-clinical studies.
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Affiliation(s)
- Stephen W Attwood
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK.
| | - Michael J Edel
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
- Control of Pluripotency Laboratory, Department of Physiological Sciences I, Faculty of Medicine, University of Barcelona, Hospital Clinic, Casanova 143, 08036 Barcelona, Spain.
- Victor Chang Cardiac Research Institute, Sydney, NSW 2145, Australia.
- Harry Perkins Research Institute, Fiona Stanley Hospital, University of Western Australia, PO Box 404, Bull Creek, Western Australia 6149, Australia.
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Palumbo E, Russo A. Common fragile site instability in normal cells: Lessons and perspectives. Genes Chromosomes Cancer 2018; 58:260-269. [PMID: 30387295 DOI: 10.1002/gcc.22705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/25/2018] [Accepted: 10/01/2018] [Indexed: 12/26/2022] Open
Abstract
Mechanisms and events related to common fragile site (CFS) instability are well known in cancer cells. Here, we argue that normal cells remain an important experimental model to address questions related to CFS instability in the absence of alterations in cell cycle and DNA damage repair pathways, which are common features acquired in cancer. Furthermore, a major gap of knowledge concerns the stability of CFSs during gametogenesis. CFS instability in meiotic or postmeiotic stages of the germ cell line could generate chromosome deletions or large rearrangements. This in turn can lead to the functional loss of the several CFS-associated genes with tumor suppressor function. Our hypothesis is that such mutations can potentially result in genetic predisposition to develop cancer. Indirect evidence for CFS instability in human germ cells has been provided by genomic investigations in family pedigrees associated with genetic disease. The issue of CFS instability in the germ cell line should represent one of the future efforts, and may take advantage of the existence of sequence and functional conservation of CFSs between rodents and humans.
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Affiliation(s)
- Elisa Palumbo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Antonella Russo
- Department of Molecular Medicine, University of Padova, Padova, Italy
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12
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Wang H, Li S, Zhang H, Wang Y, Hao S, Wu X. BLM prevents instability of structure-forming DNA sequences at common fragile sites. PLoS Genet 2018; 14:e1007816. [PMID: 30496191 PMCID: PMC6289451 DOI: 10.1371/journal.pgen.1007816] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 12/11/2018] [Accepted: 11/07/2018] [Indexed: 01/04/2023] Open
Abstract
Genome instability often arises at common fragile sites (CFSs) leading to cancer-associated chromosomal rearrangements. However, the underlying mechanisms of how CFS protection is achieved is not well understood. We demonstrate that BLM plays an important role in the maintenance of genome stability of structure-forming AT-rich sequences derived from CFSs (CFS-AT). BLM deficiency leads to increased DSB formation and hyper mitotic recombination at CFS-AT and induces instability of the plasmids containing CFS-AT. We further showed that BLM is required for suppression of CFS breakage upon oncogene expression. Both helicase activity and ATR-mediated phosphorylation of BLM are important for preventing genetic instability at CFS-AT sequences. Furthermore, the role of BLM in protecting CFS-AT is not epistatic to that of FANCM, a translocase that is involved in preserving CFS stability. Loss of BLM helicase activity leads to drastic decrease of cell viability in FANCM deficient cells. We propose that BLM and FANCM utilize different mechanisms to remove DNA secondary structures forming at CFS-AT on replication forks, thereby preventing DSB formation and maintaining CFS stability. Common fragile sites (CFSs) are large chromosomal regions which are more prone to breakage than other places in the genome. They are a part of normal chromosome structure and are present in all human beings, but are also hotspots for chromosomal rearrangement during oncogenesis. Understanding how CFSs are protected to prevent genome instability is thus extremely important for revealing the mechanism underlying cancer development. We found that Bloom syndrome protein BLM is involved in resolving DNA secondary structures that arise at AT-rich sequences in CFSs, suggesting a critical function of BLM in protecting CFSs. We also found that this BLM function is distinct from the role of Fanconi anemia protein FANCM in protecting CFSs, and loss of both BLM and FANCM activities leads to cell death. These studies reveal important mechanisms of the maintenance of CFS stability in mammalian cells.
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Affiliation(s)
- Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Shibo Li
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Huimin Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
| | - Ya Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Shuailin Hao
- Beijing Key Laboratory of DNA Damage Response and College of Life Science, Capital Normal University, Beijing, China
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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13
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Chastain M, Zhou Q, Shiva O, Fadri-Moskwik M, Whitmore L, Jia P, Dai X, Huang C, Ye P, Chai W. Human CST Facilitates Genome-wide RAD51 Recruitment to GC-Rich Repetitive Sequences in Response to Replication Stress. Cell Rep 2017; 16:1300-1314. [PMID: 27487043 DOI: 10.1016/j.celrep.2016.06.077] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 05/23/2016] [Accepted: 06/17/2016] [Indexed: 11/25/2022] Open
Abstract
The telomeric CTC1/STN1/TEN1 (CST) complex has been implicated in promoting replication recovery under replication stress at genomic regions, yet its precise role is unclear. Here, we report that STN1 is enriched at GC-rich repetitive sequences genome-wide in response to hydroxyurea (HU)-induced replication stress. STN1 deficiency exacerbates the fragility of these sequences under replication stress, resulting in chromosome fragmentation. We find that upon fork stalling, CST proteins form distinct nuclear foci that colocalize with RAD51. Furthermore, replication stress induces physical association of CST with RAD51 in an ATR-dependent manner. Strikingly, CST deficiency diminishes HU-induced RAD51 foci formation and reduces RAD51 recruitment to telomeres and non-telomeric GC-rich fragile sequences. Collectively, our findings establish that CST promotes RAD51 recruitment to GC-rich repetitive sequences in response to replication stress to facilitate replication restart, thereby providing insights into the mechanism underlying genome stability maintenance.
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Affiliation(s)
- Megan Chastain
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Qing Zhou
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Olga Shiva
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Maria Fadri-Moskwik
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Leanne Whitmore
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Pingping Jia
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Xueyu Dai
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Chenhui Huang
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA
| | - Ping Ye
- Department of Molecular and Experimental Medicine, Avera Cancer Institute, 1000 E 23rd Street, Suite 370, Sioux Falls, SD 57105, USA; Department of Pharmacy Practice, South Dakota State University, Brookings, SD 57007, USA
| | - Weihang Chai
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, WA 99210, USA.
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14
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Irony-Tur Sinai M, Kerem B. DNA replication stress drives fragile site instability. Mutat Res 2017; 808:56-61. [PMID: 29074228 DOI: 10.1016/j.mrfmmm.2017.10.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/26/2017] [Accepted: 10/12/2017] [Indexed: 12/21/2022]
Abstract
DNA replication stress is one of the early drivers enabling the ongoing acquisition of genetic changes arising during tumorigenesis. As such, it is a feature of most pre-malignant and malignant cells. In this review article, we focus on the early events initiating DNA replication stress and the preferential sensitivity of common fragile sites (CFSs) to this stress. CFSs are specific genomic regions within the normal chromosomal structure, which appear as gaps and breaks in the metaphase chromosomes of cells grown under mild replication stress conditions. The main characteristics predisposing CFSs to instability include late replication timing, delayed replication completion, failure to activate additional origins, origin paucity along large genomic regions, collision between replication and transcription complexes along large genes, and the presence of AT-dinucleotide rich sequences. The contribution of these features to instability at CFSs during early cancer development is discussed.
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Affiliation(s)
- Michal Irony-Tur Sinai
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, 91904, Israel
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, 91904, Israel.
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15
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Turinetto V, Orlando L, Giachino C. Induced Pluripotent Stem Cells: Advances in the Quest for Genetic Stability during Reprogramming Process. Int J Mol Sci 2017; 18:E1952. [PMID: 28902128 PMCID: PMC5618601 DOI: 10.3390/ijms18091952] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 09/01/2017] [Accepted: 09/08/2017] [Indexed: 12/19/2022] Open
Abstract
Evaluation of the extent and nature of induced pluripotent stem cell (iPSC) genetic instability is important for both basic research and future clinical use. As previously demonstrated regarding embryonic stem cells, such DNA aberrations might affect the differentiation capacity of the cells and increase their tumorigenicity. Here, we first focus on the contribution of multiple DNA damage response pathways during cellular reprogramming. We then discuss the origin and mechanisms responsible for the modification of genetic material in iPSCs (pre-existing variations in somatic cells, mutations induced by reprogramming factors, and mutations induced by culture expansion) and deepen the possible functional consequences of genetic variations in these cells. Lastly, we present some recent improvements of iPSC generation methods aimed at obtaining cells with fewer genetic variations.
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Affiliation(s)
- Valentina Turinetto
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, 10043 Orbassano, Turin, Italy.
| | - Luca Orlando
- McMaster Stem Cell and Cancer Research Institute, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8S 4L8, Canada.
| | - Claudia Giachino
- Department of Clinical and Biological Sciences, University of Turin, Regione Gonzole 10, 10043 Orbassano, Turin, Italy.
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16
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Bournique E, Dall'Osto M, Hoffmann JS, Bergoglio V. Role of specialized DNA polymerases in the limitation of replicative stress and DNA damage transmission. Mutat Res 2017; 808:62-73. [PMID: 28843435 DOI: 10.1016/j.mrfmmm.2017.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 01/31/2023]
Abstract
Replication stress is a strong and early driving force for genomic instability and tumor development. Beside replicative DNA polymerases, an emerging group of specialized DNA polymerases is involved in the technical assistance of the replication machinery in order to prevent replicative stress and its deleterious consequences. During S-phase, altered progression of the replication fork by endogenous or exogenous impediments induces replicative stress, causing cells to reach mitosis with genomic regions not fully duplicated. Recently, specific mechanisms to resolve replication intermediates during mitosis with the aim of limiting DNA damage transmission to daughter cells have been identified. In this review, we detail the two major actions of specialized DNA polymerases that limit DNA damage transmission: the prevention of replicative stress by non-B DNA replication and the recovery of stalled replication forks.
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Affiliation(s)
- Elodie Bournique
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Marina Dall'Osto
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Jean-Sébastien Hoffmann
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France
| | - Valérie Bergoglio
- CRCT, Université de Toulouse, Inserm, CNRS, UPS Equipe Labellisée Ligue Contre le Cancer, Laboratoire d'Excellence Toulouse Cancer, 2 Avenue Hubert Curien, 31037, Toulouse, France.
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17
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Abstract
Replication forks encounter obstacles that must be repaired or bypassed to complete chromosome duplication before cell division. Proteomic analysis of replication forks suggests that the checkpoint and repair machinery travels with unperturbed forks, implying that they are poised to respond to stalling and collapse. However, impaired fork progression still generates aberrations, including repeat copy number instability and chromosome rearrangements. Deregulated origin firing also causes fork instability if a newer fork collides with an older one, generating double-strand breaks (DSBs) and partially rereplicated DNA. Current evidence suggests that multiple mechanisms are used to repair rereplication damage, yet these can have deleterious consequences for genome integrity.
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18
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Palovcak A, Liu W, Yuan F, Zhang Y. Maintenance of genome stability by Fanconi anemia proteins. Cell Biosci 2017; 7:8. [PMID: 28239445 PMCID: PMC5320776 DOI: 10.1186/s13578-016-0134-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 12/07/2016] [Indexed: 12/20/2022] Open
Abstract
Persistent dysregulation of the DNA damage response and repair in cells causes genomic instability. The resulting genetic changes permit alterations in growth and proliferation observed in virtually all cancers. However, an unstable genome can serve as a double-edged sword by providing survival advantages in the ability to evade checkpoint signaling, but also creating vulnerabilities through dependency on alternative genomic maintenance factors. The Fanconi anemia pathway comprises an intricate network of DNA damage signaling and repair that are critical for protection against genomic instability. The importance of this pathway is underlined by the severity of the cancer predisposing syndrome Fanconi anemia which can be caused by biallelic mutations in any one of the 21 genes known thus far. This review delineates the roles of the Fanconi anemia pathway and the molecular actions of Fanconi anemia proteins in confronting replicative, oxidative, and mitotic stress.
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Affiliation(s)
- Anna Palovcak
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
| | - Wenjun Liu
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
| | - Fenghua Yuan
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
| | - Yanbin Zhang
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Gautier Building Room 311, 1011 NW 15th Street, Miami, FL 33136 USA
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19
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Mansilla SF, Bertolin AP, Bergoglio V, Pillaire MJ, González Besteiro MA, Luzzani C, Miriuka SG, Cazaux C, Hoffmann JS, Gottifredi V. Cyclin Kinase-independent role of p21 CDKN1A in the promotion of nascent DNA elongation in unstressed cells. eLife 2016; 5. [PMID: 27740454 PMCID: PMC5120883 DOI: 10.7554/elife.18020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 10/07/2016] [Indexed: 01/01/2023] Open
Abstract
The levels of the cyclin-dependent kinase (CDK) inhibitor p21 are low in S phase and insufficient to inhibit CDKs. We show here that endogenous p21, instead of being residual, it is functional and necessary to preserve the genomic stability of unstressed cells. p21depletion slows down nascent DNA elongation, triggers permanent replication defects and promotes the instability of hard-to-replicate genomic regions, namely common fragile sites (CFS). The p21’s PCNA interacting region (PIR), and not its CDK binding domain, is needed to prevent the replication defects and the genomic instability caused by p21 depletion. The alternative polymerase kappa is accountable for such defects as they were not observed after simultaneous depletion of both p21 and polymerase kappa. Hence, in CDK-independent manner, endogenous p21 prevents a type of genomic instability which is not triggered by endogenous DNA lesions but by a dysregulation in the DNA polymerase choice during genomic DNA synthesis. DOI:http://dx.doi.org/10.7554/eLife.18020.001 Cancer develops when cells in the body mutate in ways that allow them to rapidly grow and divide. To protect cells from becoming cancerous, various molecules act like guardians to prevent cells from dividing when their DNA is damaged, or if they are short of energy. Other guardian molecules monitor the DNA copying process to ensure that the newly-made DNA is as identical as possible to the original DNA template. A protein called p21 belongs to the first group of guardian molecules: DNA damage triggers the production of p21, which prevents the cell from copying its DNA. This role relies on a section of the protein called the CDK binding domain. Cells that have already started to copy their genetic material also have low levels of p21. Mansilla et al. used human cells to investigate whether p21 is also involved in the process of copying DNA. The experiments show that the low levels of p21 act to increase the speed at which the DNA is copied. This activity helps to ensure that all of the cell’s DNA is copied within the time available, including sections of DNA that are harder to copy because they are more fragile and prone to damage. This newly identified role does not involve the CDK binding domain, but instead requires a different section of the p21 protein known as the PCNA interacting region. Mansilla et al. propose that p21 plays a dual role in protecting us from developing cancer. The PCNA interacting region is also found in other proteins that are involved in copying DNA. Therefore, a future challenge is to find out how these proteins interact with each other to ensure that cells accurately copy their DNA in a timely fashion. DOI:http://dx.doi.org/10.7554/eLife.18020.002
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Affiliation(s)
- Sabrina F Mansilla
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Agustina P Bertolin
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Valérie Bergoglio
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Marie-Jeanne Pillaire
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Marina A González Besteiro
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Carlos Luzzani
- Laboratorio de Investigaciones Aplicadas en Neurociencias, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia, Belén de Escobar, Argentina
| | - Santiago G Miriuka
- Laboratorio de Investigaciones Aplicadas en Neurociencias, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia, Belén de Escobar, Argentina
| | - Christophe Cazaux
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Jean-Sébastien Hoffmann
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Vanesa Gottifredi
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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20
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Chumki SA, Dunn MK, Coates TF, Mishler JD, Younkin EM, Casper AM. Remarkably Long-Tract Gene Conversion Induced by Fragile Site Instability in Saccharomyces cerevisiae. Genetics 2016; 204:115-28. [PMID: 27343237 PMCID: PMC5012379 DOI: 10.1534/genetics.116.191205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 06/23/2016] [Indexed: 01/29/2023] Open
Abstract
Replication stress causes breaks at chromosomal locations called common fragile sites. Deletions causing loss of heterozygosity (LOH) in human tumors are strongly correlated with common fragile sites, but the role of gene conversion in LOH at fragile sites in tumors is less well studied. Here, we investigated gene conversion stimulated by instability at fragile site FS2 in the yeast Saccharomyces cerevisiae In our screening system, mitotic LOH events near FS2 are identified by production of red/white sectored colonies. We analyzed single nucleotide polymorphisms between homologs to determine the cause and extent of LOH. Instability at FS2 increases gene conversion 48- to 62-fold, and conversions unassociated with crossover represent 6-7% of LOH events. Gene conversion can result from repair of mismatches in heteroduplex DNA during synthesis-dependent strand annealing (SDSA), double-strand break repair (DSBR), and from break-induced replication (BIR) that switches templates [double BIR (dBIR)]. It has been proposed that SDSA and DSBR typically result in shorter gene-conversion tracts than dBIR. In cells under replication stress, we found that bidirectional tracts at FS2 have a median length of 40.8 kb and a wide distribution of lengths; most of these tracts are not crossover-associated. Tracts that begin at the fragile site FS2 and extend only distally are significantly shorter. The high abundance and long length of noncrossover, bidirectional gene-conversion tracts suggests that dBIR is a prominent mechanism for repair of lesions at FS2, thus this mechanism is likely to be a driver of common fragile site-stimulated LOH in human tumors.
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Affiliation(s)
- Shahana A Chumki
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan 48197
| | - Mikael K Dunn
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan 48197
| | - Thomas F Coates
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan 48197
| | - Jeanmarie D Mishler
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan 48197
| | - Ellen M Younkin
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan 48197
| | - Anne M Casper
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan 48197
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21
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Miron K, Kerem B. To break or not to break - context matters. Mol Cell Oncol 2016; 3:e1072657. [PMID: 27308576 DOI: 10.1080/23723556.2015.1072657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 07/08/2015] [Accepted: 07/08/2015] [Indexed: 10/23/2022]
Abstract
Oncogene expression can lead to replication stress and genome instability. Recently, we identified oncogene-induced fragile sites (FSs) and revealed that the landscape of recurrent fragility in the same cell type is dynamic. This implies an additional level of complexity in the molecular basis of recurrent fragility in cancer.
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Affiliation(s)
- Karin Miron
- 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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22
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Lamm N, Maoz K, Bester AC, Im MM, Shewach DS, Karni R, Kerem B. Folate levels modulate oncogene-induced replication stress and tumorigenicity. EMBO Mol Med 2016. [PMID: 26197802 PMCID: PMC4568948 DOI: 10.15252/emmm.201404824] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Chromosomal instability in early cancer stages is caused by replication stress. One mechanism by which oncogene expression induces replication stress is to drive cell proliferation with insufficient nucleotide levels. Cancer development is driven by alterations in both genetic and environmental factors. Here, we investigated whether replication stress can be modulated by both genetic and non-genetic factors and whether the extent of replication stress affects the probability of neoplastic transformation. To do so, we studied the effect of folate, a micronutrient that is essential for nucleotide biosynthesis, on oncogene-induced tumorigenicity. We show that folate deficiency by itself leads to replication stress in a concentration-dependent manner. Folate deficiency significantly enhances oncogene-induced replication stress, leading to increased DNA damage and tumorigenicity in vitro. Importantly, oncogene-expressing cells, when grown under folate deficiency, exhibit a significantly increased frequency of tumor development in mice. These findings suggest that replication stress is a quantitative trait affected by both genetic and non-genetic factors and that the extent of replication stress plays an important role in cancer development.
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Affiliation(s)
- Noa Lamm
- Department of Genetics, The Alexander Silberman Institute of Life Sciences Edmond J. Safra Campus The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Karin Maoz
- Department of Genetics, The Alexander Silberman Institute of Life Sciences Edmond J. Safra Campus The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Assaf C Bester
- Department of Genetics, The Alexander Silberman Institute of Life Sciences Edmond J. Safra Campus The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael M Im
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Donna S Shewach
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Rotem Karni
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Batsheva Kerem
- Department of Genetics, The Alexander Silberman Institute of Life Sciences Edmond J. Safra Campus The Hebrew University of Jerusalem, Jerusalem, Israel
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23
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Choe KN, Nicolae CM, Constantin D, Imamura Kawasawa Y, Delgado-Diaz MR, De S, Freire R, Smits VA, Moldovan GL. HUWE1 interacts with PCNA to alleviate replication stress. EMBO Rep 2016; 17:874-86. [PMID: 27146073 DOI: 10.15252/embr.201541685] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 04/05/2016] [Indexed: 02/01/2023] Open
Abstract
Defects in DNA replication, DNA damage response, and DNA repair compromise genomic stability and promote cancer development. In particular, unrepaired DNA lesions can arrest the progression of the DNA replication machinery during S-phase, causing replication stress, mutations, and DNA breaks. HUWE1 is a HECT-type ubiquitin ligase that targets proteins involved in cell fate, survival, and differentiation. Here, we report that HUWE1 is essential for genomic stability, by promoting replication of damaged DNA We show that HUWE1-knockout cells are unable to mitigate replication stress, resulting in replication defects and DNA breakage. Importantly, we find that this novel role of HUWE1 requires its interaction with the replication factor PCNA, a master regulator of replication fork restart, at stalled replication forks. Finally, we provide evidence that HUWE1 mono-ubiquitinates H2AX to promote signaling at stalled forks. Altogether, our work identifies HUWE1 as a novel regulator of the replication stress response.
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Affiliation(s)
- Katherine N Choe
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Daniel Constantin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Yuka Imamura Kawasawa
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA Department of Pharmacology, The Pennsylvania State University College of Medicine, Hershey, PA, USA Institute for Personalized Medicine, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Maria Rocio Delgado-Diaz
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna Tenerife, Spain
| | - Subhajyoti De
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO, USA Molecular Oncology Program, University of Colorado Cancer Center, Aurora, CO, USA
| | - Raimundo Freire
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna Tenerife, Spain
| | - Veronique Aj Smits
- Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, La Laguna Tenerife, Spain
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
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24
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Ghamrasni SE, Cardoso R, Li L, Guturi KKN, Bjerregaard VA, Liu Y, Venkatesan S, Hande MP, Henderson JT, Sanchez O, Hickson ID, Hakem A, Hakem R. Rad54 and Mus81 cooperation promotes DNA damage repair and restrains chromosome missegregation. Oncogene 2016; 35:4836-45. [PMID: 26876210 DOI: 10.1038/onc.2016.16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/03/2015] [Accepted: 11/10/2015] [Indexed: 12/18/2022]
Abstract
Rad54 and Mus81 mammalian proteins physically interact and are important for the homologous recombination DNA repair pathway; however, their functional interactions in vivo are poorly defined. Here, we show that combinatorial loss of Rad54 and Mus81 results in hypersensitivity to DNA-damaging agents, defects on both the homologous recombination and non-homologous DNA end joining repair pathways and reduced fertility. We also observed that while Mus81 deficiency diminished the cleavage of common fragile sites, very strikingly, Rad54 loss impaired this cleavage to even a greater extent. The inefficient repair of DNA double-strand breaks (DSBs) in Rad54(-/-)Mus81(-/-) cells was accompanied by elevated levels of chromosome missegregation and cell death. Perhaps as a consequence, tumor incidence in Rad54(-/-)Mus81(-/-) mice remained comparable to that in Mus81(-/-) mice. Our study highlights the importance of the cooperation between Rad54 and Mus81 for mediating DNA DSB repair and restraining chromosome missegregation.
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Affiliation(s)
- S El Ghamrasni
- Department of Medical Biophysics, University of Toronto and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - R Cardoso
- Department of Medical Biophysics, University of Toronto and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - L Li
- Department of Medical Biophysics, University of Toronto and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - K K N Guturi
- Department of Medical Biophysics, University of Toronto and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - V A Bjerregaard
- Department of Cellular and Molecular Medicine, Center for Chromosome Stability and Center for Healthy Ageing, University of Copenhagen, Panum Institute, Copenhagen, Denmark
| | - Y Liu
- Department of Cellular and Molecular Medicine, Center for Chromosome Stability and Center for Healthy Ageing, University of Copenhagen, Panum Institute, Copenhagen, Denmark
| | - S Venkatesan
- Department of Physiology, Yong Loo Lin School of Medicine and Tembusu College, National University of Singapore, Singapore
| | - M P Hande
- Department of Physiology, Yong Loo Lin School of Medicine and Tembusu College, National University of Singapore, Singapore
| | - J T Henderson
- Department of Pharmaceutical Sciences, Division of Biomolecular Science, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - O Sanchez
- Department of pathology, University of Ontario Institute of Technology, Oshawa, Ontario, Canada
| | - I D Hickson
- Department of Cellular and Molecular Medicine, Center for Chromosome Stability and Center for Healthy Ageing, University of Copenhagen, Panum Institute, Copenhagen, Denmark
| | - A Hakem
- Department of Medical Biophysics, University of Toronto and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - R Hakem
- Department of Medical Biophysics, University of Toronto and Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
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25
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Mutational spectrum of Barrett's stem cells suggests paths to initiation of a precancerous lesion. Nat Commun 2016; 7:10380. [PMID: 26783136 PMCID: PMC4735693 DOI: 10.1038/ncomms10380] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/02/2015] [Indexed: 12/22/2022] Open
Abstract
The precancerous lesion known as Barrett's oesophagus can evolve to oesophageal adenocarcinoma in decades-long processes of regenerative growth. Here we report the isolation and propagation of distinct, patient-matched stem cells of Barrett's, gastric and oesophageal epithelia that yield divergent tumour types following in vitro transformation and xenografting. Genomic analyses reveal a broad mutational spectrum unique to Barrett's stem cells that likely reflects their risk for oncogenesis. Remarkably, 25% of cases show no cancer-related genomic changes, suggesting that Barrett's initiates without driver mutations. Most cases, however, sustain patterns of deletions almost identical to adenocarcinoma though tumour-associated gene amplifications were absent. Notably, those suspected of low-grade dysplasia have p53 mutations or undergo amplifications of proto-oncogenes and receptor tyrosine kinases, implicating these events in lethal transitions. Our findings suggest paths for the initiation and progression of Barrett's and define a discrete stem cell underlying its regenerative growth whose eradication could prevent oesophageal adenocarcinoma.
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Abstract
The balance between DNA damage, especially double strand breaks, and DNA damage repair is a critical determinant of chromosomal translocation frequency. The non-homologous end-joining repair (NHEJ) pathways seem to play the major role in the generation of chromosomal translocations. The "landscape" of chromosomal translocation identified in malignancies is largely due to selection processes which operate on the growth advantages conveyed to the cells by the functional consequences of chromosomal translocations (i.e., oncogenic fusion proteins and overexpression of oncogenes, both compromising tumor suppressor gene functions). Newer studies have shown that there is an abundance of local rearrangements in many tumors, like small deletions and inversions. A better understanding of the interplay between DNA repair mechanisms and the generation of tumorigenic translocations will, among many other things, depend on an improved understanding of DNA repair mechanisms and their interplay with chromatin and the 3D organization of the interphase nucleus.
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Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects. Cell Stem Cell 2015; 18:253-61. [PMID: 26669899 DOI: 10.1016/j.stem.2015.11.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 08/31/2015] [Accepted: 11/05/2015] [Indexed: 12/27/2022]
Abstract
Human pluripotent stem cells (hPSCs) frequently acquire chromosomal aberrations such as aneuploidy in culture. These aberrations progressively increase over time and may compromise the properties and clinical utility of the cells. The underlying mechanisms that drive initial genomic instability and its continued progression are largely unknown. Here, we show that aneuploid hPSCs undergo DNA replication stress, resulting in defective chromosome condensation and segregation. Aneuploid hPSCs show altered levels of actin cytoskeletal genes controlled by the transcription factor SRF, and overexpression of SRF rescues impaired chromosome condensation and segregation defects in aneuploid hPSCs. Furthermore, SRF downregulation in diploid hPSCs induces replication stress and perturbed condensation similar to that seen in aneuploid cells. Together, these results suggest that decreased SRF expression induces replicative stress and chromosomal condensation defects that underlie the ongoing chromosomal instability seen in aneuploid hPSCs. A similar mechanism may also operate during initiation of instability in diploid cells.
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Stepanenko A, Dmitrenko V. HEK293 in cell biology and cancer research: phenotype, karyotype, tumorigenicity, and stress-induced genome-phenotype evolution. Gene 2015; 569:182-90. [DOI: 10.1016/j.gene.2015.05.065] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 05/11/2015] [Accepted: 05/26/2015] [Indexed: 01/18/2023]
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Russo A, Pacchierotti F, Cimini D, Ganem NJ, Genescà A, Natarajan AT, Pavanello S, Valle G, Degrassi F. Genomic instability: Crossing pathways at the origin of structural and numerical chromosome changes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2015; 56:563-580. [PMID: 25784636 DOI: 10.1002/em.21945] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/02/2015] [Accepted: 02/19/2015] [Indexed: 06/04/2023]
Abstract
Genomic instability leads to a wide spectrum of genetic changes, including single nucleotide mutations, structural chromosome alterations, and numerical chromosome changes. The accepted view on how these events are generated predicts that separate cellular mechanisms and genetic events explain the occurrence of these types of genetic variation. Recently, new findings have shed light on the complexity of the mechanisms leading to structural and numerical chromosome aberrations, their intertwining pathways, and their dynamic evolution, in somatic as well as in germ cells. In this review, we present a critical analysis of these recent discoveries in this area, with the aim to contribute to a deeper knowledge of the molecular networks leading to adverse outcomes in humans following exposure to environmental factors. The review illustrates how several technological advances, including DNA sequencing methods, bioinformatics, and live-cell imaging approaches, have contributed to produce a renewed concept of the mechanisms causing genomic instability. Special attention is also given to the specific pathways causing genomic instability in mammalian germ cells. Remarkably, the same scenario emerged from some pioneering studies published in the 1980s to 1990s, when the evolution of polyploidy, the chromosomal effects of spindle poisons, the fate of micronuclei, were intuitively proposed to share mechanisms and pathways. Thus, an old working hypothesis has eventually found proper validation.
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Affiliation(s)
| | - Francesca Pacchierotti
- Laboratory of Toxicology, Unit of Radiation Biology and Human Health, ENEA CR Casaccia, Rome, Italy
| | - Daniela Cimini
- Department of Biological Sciences and Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia
| | - Neil J Ganem
- Department of Pharmacology, Division of Hematology and Oncology, Boston University School of Medicine, Boston, Massachusetts
| | - Anna Genescà
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | | | - Sofia Pavanello
- Department of Cardiac, Thoracic and Vascular Sciences, Unit of Occupational Medicine, University of Padova, Italy
| | - Giorgio Valle
- Department of Biology, University of Padova, Padova, Italy
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Miron K, Golan-Lev T, Dvir R, Ben-David E, Kerem B. Oncogenes create a unique landscape of fragile sites. Nat Commun 2015; 6:7094. [DOI: 10.1038/ncomms8094] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 04/02/2015] [Indexed: 11/09/2022] Open
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Teixeira LK, Wang X, Li Y, Ekholm-Reed S, Wu X, Wang P, Reed SI. Cyclin E deregulation promotes loss of specific genomic regions. Curr Biol 2015; 25:1327-33. [PMID: 25959964 DOI: 10.1016/j.cub.2015.03.022] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 02/24/2015] [Accepted: 03/13/2015] [Indexed: 01/21/2023]
Abstract
Cell-cycle progression is regulated by the cyclin-dependent kinase (Cdk) family of protein kinases, so named because their activation depends on association with regulatory subunits known as cyclins. Cyclin E normally accumulates at the G1/S boundary, where it promotes S phase entry and progression by activating Cdk2. In normal cells, cyclin E/Cdk2 activity is associated with DNA replication-related functions. However, deregulation of cyclin E leads to inefficient assembly of pre-replication complexes, replication stress, and chromosome instability. In malignant cells, cyclin E is frequently overexpressed, correlating with decreased survival in breast cancer patients. Transgenic mice deregulated for cyclin E in the mammary epithelia develop carcinoma, confirming that cyclin E is an oncoprotein. However, it remains unknown how cyclin E-mediated replication stress promotes genomic instability during carcinogenesis. Here, we show that deregulation of cyclin E causes human mammary epithelial cells to enter into mitosis with short unreplicated genomic segments at a small number of specific loci, leading to anaphase anomalies and ultimately deletions. Incompletely replicated regions are preferentially located at late-replicating domains, fragile sites, and breakpoints, including the mixed-lineage leukemia breakpoint cluster region (MLL BCR). Furthermore, these regions are characterized by a paucity of replication origins or unusual DNA structures. Analysis of a large set of breast tumors shows a significant correlation between cyclin E amplification and deletions at a number of the genomic loci identified in our study. Our results demonstrate how oncogene-induced replication stress contributes to genomic instability in human cancer.
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Affiliation(s)
- Leonardo K Teixeira
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xianlong Wang
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Yongjiang Li
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Susanna Ekholm-Reed
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xiaohua Wu
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Pei Wang
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Steven I Reed
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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32
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Nicolae CM, Aho ER, Choe KN, Constantin D, Hu HJ, Lee D, Myung K, Moldovan GL. A novel role for the mono-ADP-ribosyltransferase PARP14/ARTD8 in promoting homologous recombination and protecting against replication stress. Nucleic Acids Res 2015; 43:3143-53. [PMID: 25753673 PMCID: PMC4381061 DOI: 10.1093/nar/gkv147] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/15/2015] [Indexed: 12/29/2022] Open
Abstract
Genomic instability, a major hallmark of cancer cells, is caused by incorrect or ineffective DNA repair. Many DNA repair mechanisms cooperate in cells to fight DNA damage, and are generally regulated by post-translational modification of key factors. Poly-ADP-ribosylation, catalyzed by PARP1, is a post-translational modification playing a prominent role in DNA repair, but much less is known about mono-ADP-ribosylation. Here we report that mono-ADP-ribosylation plays an important role in homologous recombination DNA repair, a mechanism essential for replication fork stability and double strand break repair. We show that the mono-ADP-ribosyltransferase PARP14 interacts with the DNA replication machinery component PCNA and promotes replication of DNA lesions and common fragile sites. PARP14 depletion results in reduced homologous recombination, persistent RAD51 foci, hypersensitivity to DNA damaging agents and accumulation of DNA strand breaks. Our work uncovered PARP14 as a novel factor required for mitigating replication stress and promoting genomic stability.
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Affiliation(s)
- Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Erin R Aho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Katherine N Choe
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - Daniel Constantin
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
| | - He-Juan Hu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA Suzhou Health College, Suzhou, Jiangsu 215009, P.R. China
| | - Deokjae Lee
- Genome Instability Section, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Kyungjae Myung
- Genome Instability Section, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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33
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Abstract
The primary goal of mitosis is to partition duplicated chromosomes into daughter cells. Eukaryotic chromosomes are equipped with two distinct classes of intrinsic machineries, cohesin and condensins, that ensure their faithful segregation during mitosis. Cohesin holds sister chromatids together immediately after their synthesis during S phase until the establishment of bipolar attachments to the mitotic spindle in metaphase. Condensins, on the other hand, attempt to "resolve" sister chromatids by counteracting cohesin. The products of the balancing acts of cohesin and condensins are metaphase chromosomes, in which two rod-shaped chromatids are connected primarily at the centromere. In anaphase, this connection is released by the action of separase that proteolytically cleaves the remaining population of cohesin. Recent studies uncover how this series of events might be mechanistically coupled with each other and intricately regulated by a number of regulatory factors.
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Affiliation(s)
- Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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34
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Twa DDW, Steidl C. Structural genomic alterations in primary mediastinal large B-cell lymphoma. Leuk Lymphoma 2015; 56:2239-50. [DOI: 10.3109/10428194.2014.985673] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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35
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Franchitto A, Pichierri P. Replication fork recovery and regulation of common fragile sites stability. Cell Mol Life Sci 2014; 71:4507-17. [PMID: 25216703 PMCID: PMC11113654 DOI: 10.1007/s00018-014-1718-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
Abstract
The acquisition of genomic instability is a triggering factor in cancer development, and common fragile sites (CFS) are the preferential target of chromosomal instability under conditions of replicative stress in the human genome. Although the mechanisms leading to CFS expression and the cellular factors required to suppress CFS instability remain largely undefined, it is clear that DNA becomes more susceptible to breakage when replication is impaired. The models proposed so far to explain how CFS instability arises imply that replication fork progression along these regions is perturbed due to intrinsic features of fragile sites and events that directly affect DNA replication. The observation that proteins implicated in the safe recovery of stalled forks or in engaging recombination at collapsed forks increase CFS expression when downregulated or mutated suggests that the stabilization and recovery of perturbed replication forks are crucial to guarantee CFS integrity.
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Affiliation(s)
- Annapaola Franchitto
- Section of Molecular Epidemiology, Department of Environment and Primary Prevention, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161, Rome, Italy,
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36
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Aqeilan RI, Abu-Remaileh M, Abu-Odeh M. The common fragile site FRA16D gene product WWOX: roles in tumor suppression and genomic stability. Cell Mol Life Sci 2014; 71:4589-99. [PMID: 25245215 PMCID: PMC11113097 DOI: 10.1007/s00018-014-1724-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 10/24/2022]
Abstract
The fragile WWOX gene, encompassing the chromosomal fragile site FRA16D, is frequently altered in human cancers. While vulnerable to DNA damage itself, recent evidence has shown that the WWOX protein is essential for proper DNA damage response (DDR). Furthermore, the gene product, WWOX, has been associated with multiple protein networks, highlighting its critical functions in normal cell homeostasis. Targeted deletion of Wwox in murine models suggests its in vivo requirement for proper growth, metabolism, and survival. Recent molecular and biochemical analyses of WWOX functions highlighted its role in modulating aerobic glycolysis and genomic stability. Cumulatively, we propose that the gene product of FRA16D, WWOX, is a functionally essential protein that is required for cell homeostasis and that its deletion has important consequences that contribute to the neoplastic process. This review discusses the essential role of WWOX in tumor suppression and genomic stability and how its alteration contributes to cancer transformation.
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Affiliation(s)
- Rami I Aqeilan
- The Lautenberg Center for Immunology and Cancer Research, IMRIC, Faculty of Medicine, Hebrew University of Jerusalem, 91220, Jerusalem, Israel,
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37
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Abu-Odeh M, Salah Z, Herbel C, Hofmann TG, Aqeilan RI. WWOX, the common fragile site FRA16D gene product, regulates ATM activation and the DNA damage response. Proc Natl Acad Sci U S A 2014; 111:E4716-25. [PMID: 25331887 PMCID: PMC4226089 DOI: 10.1073/pnas.1409252111] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Genomic instability is a hallmark of cancer. The WW domain-containing oxidoreductase (WWOX) is a tumor suppressor spanning the common chromosomal fragile site FRA16D. Here, we report a direct role of WWOX in DNA damage response (DDR) and DNA repair. We show that Wwox deficiency results in reduced activation of the ataxia telangiectasia-mutated (ATM) checkpoint kinase, inefficient induction and maintenance of γ-H2AX foci, and impaired DNA repair. Mechanistically, we show that, upon DNA damage, WWOX accumulates in the cell nucleus, where it interacts with ATM and enhances its activation. Nuclear accumulation of WWOX is regulated by its K63-linked ubiquitination at lysine residue 274, which is mediated by the E3 ubiquitin ligase ITCH. These findings identify a novel role for the tumor suppressor WWOX and show that loss of WWOX expression may drive genomic instability and provide an advantage for clonal expansion of neoplastic cells.
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Affiliation(s)
- Mohammad Abu-Odeh
- The Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research-Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Zaidoun Salah
- The Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research-Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; Al Quds-Bard College, Al-Quds University, Abu Dies, East Jerusalem; and
| | - Christoph Herbel
- German Cancer Research Center, Cellular Senescence Group, German Cancer Research Center-Zentrum für Molekulare Biologie der Universität Heidelberg Alliance, 69120 Heidelberg, Germany
| | - Thomas G Hofmann
- German Cancer Research Center, Cellular Senescence Group, German Cancer Research Center-Zentrum für Molekulare Biologie der Universität Heidelberg Alliance, 69120 Heidelberg, Germany
| | - Rami I Aqeilan
- The Lautenberg Center for General and Tumor Immunology, Department of Immunology and Cancer Research-Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel;
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38
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Lan YY, Londoño D, Bouley R, Rooney MS, Hacohen N. Dnase2a deficiency uncovers lysosomal clearance of damaged nuclear DNA via autophagy. Cell Rep 2014; 9:180-192. [PMID: 25284779 DOI: 10.1016/j.celrep.2014.08.074] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 07/30/2014] [Accepted: 08/28/2014] [Indexed: 12/22/2022] Open
Abstract
Deficiencies in DNA-degrading nucleases lead to accumulation of self DNA and induction of autoimmunity in mice and in monogenic and polygenic human diseases. However, the sources of DNA and the mechanisms that trigger immunity remain unclear. We analyzed mice deficient for the lysosomal nuclease Dnase2a and observed elevated levels of undegraded DNA in both phagocytic and nonphagocytic cells. In nonphagocytic cells, the excess DNA originated from damaged DNA in the nucleus based on colocalization studies, live-cell imaging, and exacerbation by DNA-damaging agents. Removal of damaged DNA by Dnase2a required nuclear export and autophagy-mediated delivery of the DNA to lysosomes. Finally, DNA was found to accumulate in Dnase2a(-/-) or autophagy-deficient cells and induce inflammation via the Sting cytosolic DNA-sensing pathway. Our results reveal a cell-autonomous process for removal of damaged nuclear DNA with implications for conditions with elevated DNA damage, such as inflammation, cancer, and chemotherapy.
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Affiliation(s)
- Yuk Yuen Lan
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, 149 13(th) Street, Charlestown, MA 02129, USA; Broad Institute, 415 Main Street, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Diana Londoño
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, 149 13(th) Street, Charlestown, MA 02129, USA
| | - Richard Bouley
- Center for Systems Biology, Program in Membrane Biology and Nephrology Division, Massachusetts General Hospital, 185 Cambridge Street, Boston, MA 02114, USA
| | - Michael S Rooney
- Broad Institute, 415 Main Street, Cambridge, MA 02142, USA; Harvard/MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Nir Hacohen
- Center for Immunology and Inflammatory Diseases, Massachusetts General Hospital, 149 13(th) Street, Charlestown, MA 02129, USA; Broad Institute, 415 Main Street, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
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39
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Georgakilas AG, Tsantoulis P, Kotsinas A, Michalopoulos I, Townsend P, Gorgoulis VG. Are common fragile sites merely structural domains or highly organized "functional" units susceptible to oncogenic stress? Cell Mol Life Sci 2014; 71:4519-44. [PMID: 25238782 PMCID: PMC4232749 DOI: 10.1007/s00018-014-1717-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 01/07/2023]
Abstract
Common fragile sites (CFSs) are regions of the genome with a predisposition to DNA double-strand breaks in response to intrinsic (oncogenic) or extrinsic replication stress. CFS breakage is a common feature in carcinogenesis from its earliest stages. Given that a number of oncogenes and tumor suppressors are located within CFSs, a question that emerges is whether fragility in these regions is only a structural “passive” incident or an event with a profound biological effect. Furthermore, there is sparse evidence that other elements, like non-coding RNAs, are positioned with them. By analyzing data from various libraries, like miRbase and ENCODE, we show a prevalence of various cancer-related genes, miRNAs, and regulatory binding sites, such as CTCF within CFSs. We propose that CFSs are not only susceptible structural domains, but highly organized “functional” entities that when targeted, severe repercussion for cell homeostasis occurs.
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Affiliation(s)
- Alexandros G Georgakilas
- Physics Department, School of Applied Mathematical and Physical Sciences, National Technical University of Athens (NTUA), Zografou, 15780, Athens, Greece
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40
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House NCM, Koch MR, Freudenreich CH. Chromatin modifications and DNA repair: beyond double-strand breaks. Front Genet 2014; 5:296. [PMID: 25250043 PMCID: PMC4155812 DOI: 10.3389/fgene.2014.00296] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 08/08/2014] [Indexed: 12/28/2022] Open
Abstract
DNA repair must take place in the context of chromatin, and chromatin modifications and DNA repair are intimately linked. The study of double-strand break repair has revealed numerous histone modifications that occur after induction of a DSB, and modification of the repair factors themselves can also occur. In some cases the function of the modification is at least partially understood, but in many cases it is not yet clear. Although DSB repair is a crucial activity for cell survival, DSBs account for only a small percentage of the DNA lesions that occur over the lifetime of a cell. Repair of single-strand gaps, nicks, stalled forks, alternative DNA structures, and base lesions must also occur in a chromatin context. There is increasing evidence that these repair pathways are also regulated by histone modifications and chromatin remodeling. In this review, we will summarize the current state of knowledge of chromatin modifications that occur during non-DSB repair, highlighting similarities and differences to DSB repair as well as remaining questions.
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Affiliation(s)
| | - Melissa R Koch
- Department of Biology, Tufts University Medford, MA, USA
| | - Catherine H Freudenreich
- Department of Biology, Tufts University Medford, MA, USA ; Program in Genetics, Sackler School of Graduate Biomedical Sciences, Tufts University Boston, MA, USA
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41
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Alver RC, Chadha GS, Blow JJ. The contribution of dormant origins to genome stability: from cell biology to human genetics. DNA Repair (Amst) 2014; 19:182-9. [PMID: 24767947 PMCID: PMC4065331 DOI: 10.1016/j.dnarep.2014.03.012] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The ability of a eukaryotic cell to precisely and accurately replicate its DNA is crucial to maintain genome stability. Here we describe our current understanding of the process by which origins are licensed for DNA replication and review recent work suggesting that fork stalling has exerted a strong selective pressure on the positioning of licensed origins. In light of this, we discuss the complex and disparate phenotypes observed in mouse models and humans patients that arise due to defects in replication licensing proteins.
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Affiliation(s)
- Robert C Alver
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Gaganmeet Singh Chadha
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - J Julian Blow
- Centre for Gene Regulation & Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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42
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The origins and processing of ultra fine anaphase DNA bridges. Curr Opin Genet Dev 2014; 26:1-5. [PMID: 24795279 DOI: 10.1016/j.gde.2014.03.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/13/2014] [Accepted: 03/12/2014] [Indexed: 01/26/2023]
Abstract
Ultra-fine DNA bridges (UFBs) are a recently identified class of mitotic DNA structures that cannot be visualized using conventional DNA staining methods (e.g. using DAPI). Their existence can currently only be revealed by immuno-fluorescent staining for proteins that bind to them, including PICH and BLM. UFBs become visible in the anaphase of mitosis, and can persist into telophase in rare cases. There are at least three different types of UFBs that can be distinguished according to the chromosomal loci from which they originate. However, it remains largely unknown how these UFBs are generated or resolved in the cell. In this article, we will review our current understanding of different types of UFBs and the potential functional role of the proteins that have been shown to be associated with them.
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43
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The RBBP6/ZBTB38/MCM10 axis regulates DNA replication and common fragile site stability. Cell Rep 2014; 7:575-587. [PMID: 24726359 DOI: 10.1016/j.celrep.2014.03.030] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/17/2014] [Accepted: 03/09/2014] [Indexed: 11/23/2022] Open
Abstract
Faithful DNA replication is essential for the maintenance of genome integrity. Incomplete genome replication leads to DNA breaks and chromosomal rearrangements, which are causal factors in cancer and other human diseases. Despite their importance, the molecular mechanisms that control human genome stability are incompletely understood. Here, we report a pathway that is required for human genome replication and stability. This pathway has three components: an E3 ubiquitin ligase, a transcriptional repressor, and a replication protein. The E3 ubiquitin ligase RBBP6 ubiquitinates and destabilizes the transcriptional repressor ZBTB38. This repressor negatively regulates transcription and levels of the MCM10 replication factor on chromatin. Cells lacking RBBP6 experience reduced replication fork progression and increased damage at common fragile sites due to ZBTB38 accumulation and MCM10 downregulation. Our results uncover a pathway that ensures genome-wide DNA replication and chromosomal stability.
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Schwartz M, Hakim O. 3D view of chromosomes, DNA damage, and translocations. Curr Opin Genet Dev 2014; 25:118-25. [PMID: 24632298 DOI: 10.1016/j.gde.2013.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 12/26/2013] [Indexed: 02/02/2023]
Abstract
The cell nucleus is a busy and organized organelle. In this megalopolis made of billions of nucleotides, protein factors find their target loci to exert nuclear functions such as transcription and replication. Remarkably, despite the lack of internal membrane barrier, the interlinked and tightly regulated nuclear processes occur in spatially organized fashion. These processes can lead to double-strand breaks (DSBs) that compromise the integrity of the genome. Moreover, in some cells like lymphocytes, DNA damage is also targeted within the context of immunoglobulin gene recombination. If not repaired correctly, DSBs can cause chromosomal rearrangements, including translocations which are etiological in numerous tumors. Therefore, the chromosomal locations of DSBs, as well as their spatial positioning, are important contributors to formation of chromosomal translocations at specific genomic loci. To obtain a mechanistic understanding of chromosomal translocations these parameters should be accounted for in a global and integrative fashion. In this review we will discuss recent findings addressing how genome architecture, DNA damage, and repair contribute to the genesis of chromosomal translocations.
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Affiliation(s)
- Michal Schwartz
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Israel
| | - Ofir Hakim
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Israel.
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45
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Thomay K, Schienke A, Vajen B, Modlich U, Schambach A, Hofmann W, Schlegelberger B, Göhring G. Chromosomal Instability and Telomere Shortening in Long-Term Culture of Hematopoietic Stem Cells: Insights from a Cell Culture Model of RPS14 Haploinsufficiency. Cytogenet Genome Res 2014; 142:14-20. [DOI: 10.1159/000356096] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2013] [Indexed: 11/19/2022] Open
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Minocherhomji S, Hickson ID. Structure-specific endonucleases: guardians of fragile site stability. Trends Cell Biol 2013; 24:321-7. [PMID: 24361091 DOI: 10.1016/j.tcb.2013.11.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 12/26/2022]
Abstract
Fragile sites are conserved loci predisposed to form breaks in metaphase chromosomes. The inherent instability of these loci is associated with chromosomal rearrangements in cancers and is a feature of cells from patients with chromosomal instability syndromes. One class of fragile sites, the common fragile sites (CFSs), have previously been shown to recruit several DNA repair proteins after the completion of bulk DNA synthesis in the cell, probably indicative of their inability to complete timely DNA replication. CFS loci are also prone to trigger mitotic non-disjunction of sister chromatids, leading to the formation of ultra-fine anaphase bridges (UFBs) and micronuclei. We discuss recent developments in the CFS field; in particular, the role of DNA structure-specific endonucleases in promoting cleavage at CFSs.
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Affiliation(s)
- Sheroy Minocherhomji
- Nordea Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark
| | - Ian D Hickson
- Nordea Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark.
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Hosseini SA, Horton S, Saldivar JC, Miuma S, Stampfer MR, Heerema NA, Huebner K. Common chromosome fragile sites in human and murine epithelial cells and FHIT/FRA3B loss-induced global genome instability. Genes Chromosomes Cancer 2013; 52:1017-29. [PMID: 23929738 PMCID: PMC4293015 DOI: 10.1002/gcc.22097] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/06/2013] [Indexed: 01/21/2023] Open
Abstract
Chromosomal positions of common fragile sites differ in lymphoblasts and fibroblasts, with positions dependent on the epigenetically determined density of replication origins at these loci. Because rearrangement of fragile loci and associated loss of fragile gene products are hallmarks of cancers, we aimed to map common fragile sites in epithelial cells, from which most cancers derive. Among the five most frequently activated sites in human epithelial cells were chromosome bands 2q33 and Xq22.1, which are not among top fragile sites identified in lymphoblasts or fibroblasts. FRA16D at 16q23 was among the top three fragile sites in the human epithelial cells examined, as it is in lymphoblasts and fibroblasts, while FRA3B at 3p14.2, the top fragile locus in lymphoblasts, was not fragile in most epithelial cell lines tested. Epithelial cells exhibited varying hierarchies of fragile sites; some frequent epithelial cell fragile sites are apparently not frequently altered in epithelial cancers and sites that are frequently deleted in epithelial cancers are not necessarily among the most fragile. Since we have reported that loss of expression of the FRA3B-encoded FHIT protein causes increased replication stress-induced DNA damage, we also examined the effect of FHIT-deficiency on markers of genome instability in epithelial cells. FHIT-deficient cells exhibited increases in fragile breaks and in γH2AX and 53BP1 foci in G1 phase cells, confirming in epithelial cells that the FHIT gene and encompassing FRA3B, is a "caretaker gene" necessary for maintenance of genome stability.
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Affiliation(s)
- Seyed Ali Hosseini
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Susan Horton
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Joshua C. Saldivar
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Satoshi Miuma
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Martha R. Stampfer
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA
| | - Nyla A. Heerema
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH
| | - Kay Huebner
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University Wexner Medical Center, Columbus, OH
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48
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Boyer AS, Grgurevic S, Cazaux C, Hoffmann JS. The Human Specialized DNA Polymerases and Non-B DNA: Vital Relationships to Preserve Genome Integrity. J Mol Biol 2013; 425:4767-81. [DOI: 10.1016/j.jmb.2013.09.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 12/26/2022]
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Mankouri HW, Huttner D, Hickson ID. How unfinished business from S-phase affects mitosis and beyond. EMBO J 2013; 32:2661-71. [PMID: 24065128 DOI: 10.1038/emboj.2013.211] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/05/2013] [Indexed: 12/17/2022] Open
Abstract
The eukaryotic cell cycle is conventionally viewed as comprising several discrete steps, each of which must be completed before the next one is initiated. However, emerging evidence suggests that incompletely replicated, or unresolved, chromosomes from S-phase can persist into mitosis, where they present a potential threat to the faithful segregation of sister chromatids. In this review, we provide an overview of the different classes of loci where this 'unfinished S-phase business' can lead to a variety of cytogenetically distinct DNA structures throughout the various steps of mitosis. Furthermore, we discuss the potential ways in which cells might not only tolerate this inevitable aspect of chromosome biology, but also exploit it to assist in the maintenance of genome stability.
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Affiliation(s)
- Hocine W Mankouri
- Department of Cellular and Molecular Medicine, Nordea Center for Healthy Aging, Copenhagen N, Denmark
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50
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Rosen DM, Younkin EM, Miller SD, Casper AM. Fragile site instability in Saccharomyces cerevisiae causes loss of heterozygosity by mitotic crossovers and break-induced replication. PLoS Genet 2013; 9:e1003817. [PMID: 24068975 PMCID: PMC3778018 DOI: 10.1371/journal.pgen.1003817] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 08/06/2013] [Indexed: 11/19/2022] Open
Abstract
Loss of heterozygosity (LOH) at tumor suppressor loci is a major contributor to cancer initiation and progression. Both deletions and mitotic recombination can lead to LOH. Certain chromosomal loci known as common fragile sites are susceptible to DNA lesions under replication stress, and replication stress is prevalent in early stage tumor cells. There is extensive evidence for deletions stimulated by common fragile sites in tumors, but the role of fragile sites in stimulating mitotic recombination that causes LOH is unknown. Here, we have used the yeast model system to study the relationship between fragile site instability and mitotic recombination that results in LOH. A naturally occurring fragile site, FS2, exists on the right arm of yeast chromosome III, and we have analyzed LOH on this chromosome. We report that the frequency of spontaneous mitotic BIR events resulting in LOH on the right arm of yeast chromosome III is higher than expected, and that replication stress by low levels of polymerase alpha increases mitotic recombination 12-fold. Using single-nucleotide polymorphisms between the two chromosome III homologs, we mapped the locations of recombination events and determined that FS2 is a strong hotspot for both mitotic reciprocal crossovers and break-induced replication events under conditions of replication stress.
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Affiliation(s)
- Danielle M. Rosen
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
| | - Ellen M. Younkin
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
| | - Shaylynn D. Miller
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
| | - Anne M. Casper
- Department of Biology, Eastern Michigan University, Ypsilanti, Michigan, United States of America
- * E-mail:
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