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Courtot L, Hoffmann JS, Bergoglio V. The Protective Role of Dormant Origins in Response to Replicative Stress. Int J Mol Sci 2018; 19:ijms19113569. [PMID: 30424570 PMCID: PMC6274952 DOI: 10.3390/ijms19113569] [Citation(s) in RCA: 30] [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: 10/02/2018] [Revised: 11/05/2018] [Accepted: 11/07/2018] [Indexed: 02/07/2023] Open
Abstract
Genome stability requires tight regulation of DNA replication to ensure that the entire genome of the cell is duplicated once and only once per cell cycle. In mammalian cells, origin activation is controlled in space and time by a cell-specific and robust program called replication timing. About 100,000 potential replication origins form on the chromatin in the gap 1 (G1) phase but only 20⁻30% of them are active during the DNA replication of a given cell in the synthesis (S) phase. When the progress of replication forks is slowed by exogenous or endogenous impediments, the cell must activate some of the inactive or "dormant" origins to complete replication on time. Thus, the many origins that may be activated are probably key to protect the genome against replication stress. This review aims to discuss the role of these dormant origins as safeguards of the human genome during replicative stress.
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Affiliation(s)
- Lilas Courtot
- 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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Tsao WC, Eckert KA. Detours to Replication: Functions of Specialized DNA Polymerases during Oncogene-induced Replication Stress. Int J Mol Sci 2018; 19:ijms19103255. [PMID: 30347795 PMCID: PMC6214091 DOI: 10.3390/ijms19103255] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 10/15/2018] [Accepted: 10/15/2018] [Indexed: 01/10/2023] Open
Abstract
Incomplete and low-fidelity genome duplication contribute to genomic instability and cancer development. Difficult-to-Replicate Sequences, or DiToRS, are natural impediments in the genome that require specialized DNA polymerases and repair pathways to complete and maintain faithful DNA synthesis. DiToRS include non B-DNA secondary structures formed by repetitive sequences, for example within chromosomal fragile sites and telomeres, which inhibit DNA replication under endogenous stress conditions. Oncogene activation alters DNA replication dynamics and creates oncogenic replication stress, resulting in persistent activation of the DNA damage and replication stress responses, cell cycle arrest, and cell death. The response to oncogenic replication stress is highly complex and must be tightly regulated to prevent mutations and tumorigenesis. In this review, we summarize types of known DiToRS and the experimental evidence supporting replication inhibition, with a focus on the specialized DNA polymerases utilized to cope with these obstacles. In addition, we discuss different causes of oncogenic replication stress and its impact on DiToRS stability. We highlight recent findings regarding the regulation of DNA polymerases during oncogenic replication stress and the implications for cancer development.
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Affiliation(s)
- Wei-Chung Tsao
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.
| | - Kristin A Eckert
- Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.
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Kang SU, Park JT. Functional evaluation of alternative splicing in the FAM190A gene. Genes Genomics 2018; 41:193-199. [PMID: 30298359 DOI: 10.1007/s13258-018-0752-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 10/04/2018] [Indexed: 10/28/2022]
Abstract
The human FAM190A gene undergoes frequent alteration in human cancer, most commonly involving in-frame deletions in exon 9 or exons 9 & 10. These deletions form novel peptide sequences, serving as presumptive cancer-specific neo antigens. However, it remains elusive whether these in-frame deletions of FAM190A could induce oncogenic properties in vivo. In this study, we aimed to explore the functional significance of in-frame deletions in FAM190A genes. We generated two deletion mutant forms, FAM190AΔexon9 and FAM190AΔexon9&10, and examined their gain-of-function effects in vitro and in vivo. Global transcript profiling in NIH3T3 cells revealed that the transcripts displaying altered expression following introduction of FAM190AΔexon9 and FAM190AΔexon9&10 were significantly enriched for genes assigned to cellular movement and cell-to-cell signaling, respectively. Furthermore, ectopic expression of FAM190AΔexon9 and FAM190AΔexon9&10 induced in vivo tumor formation in nu/nu mice. Taken together, our results are the first to demonstrate the in vivo oncogenic properties of in-frame deletions in the FAM190A gene and indicate that these transcript variants might be clinically applicable as therapeutic targets in patients with cancer.
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Affiliation(s)
- Sung Ung Kang
- Institute of Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Joon Tae Park
- Division of Life Sciences, College of Life Sciences and Bioengineering, Incheon National University, Incheon, 22012, South Korea.
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Genome-wide Identification of Structure-Forming Repeats as Principal Sites of Fork Collapse upon ATR Inhibition. Mol Cell 2018; 72:222-238.e11. [PMID: 30293786 DOI: 10.1016/j.molcel.2018.08.047] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 07/11/2018] [Accepted: 08/30/2018] [Indexed: 01/22/2023]
Abstract
DNA polymerase stalling activates the ATR checkpoint kinase, which in turn suppresses fork collapse and breakage. Herein, we describe use of ATR inhibition (ATRi) as a means to identify genomic sites of problematic DNA replication in murine and human cells. Over 500 high-resolution ATR-dependent sites were ascertained using two distinct methods: replication protein A (RPA)-chromatin immunoprecipitation (ChIP) and breaks identified by TdT labeling (BrITL). The genomic feature most strongly associated with ATR dependence was repetitive DNA that exhibited high structure-forming potential. Repeats most reliant on ATR for stability included structure-forming microsatellites, inverted retroelement repeats, and quasi-palindromic AT-rich repeats. Notably, these distinct categories of repeats differed in the structures they formed and their ability to stimulate RPA accumulation and breakage, implying that the causes and character of replication fork collapse under ATR inhibition can vary in a DNA-structure-specific manner. Collectively, these studies identify key sources of endogenous replication stress that rely on ATR for stability.
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56
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Pan-Cancer Analysis Reveals Differential Susceptibility of Bidirectional Gene Promoters to DNA Methylation, Somatic Mutations, and Copy Number Alterations. Int J Mol Sci 2018; 19:ijms19082296. [PMID: 30081598 PMCID: PMC6121907 DOI: 10.3390/ijms19082296] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/26/2018] [Accepted: 08/02/2018] [Indexed: 12/12/2022] Open
Abstract
Bidirectional gene promoters affect the transcription of two genes, leading to the hypothesis that they should exhibit protection against genetic or epigenetic changes in cancer. Therefore, they provide an excellent opportunity to learn about promoter susceptibility to somatic alteration in tumors. We tested this hypothesis using data from genome-scale DNA methylation (14 cancer types), simple somatic mutation (10 cancer types), and copy number variation profiling (14 cancer types). For DNA methylation, the difference in rank differential methylation between tumor and tumor-adjacent normal matched samples based on promoter type was tested by the Wilcoxon rank sum test. Logistic regression was used to compare differences in simple somatic mutations. For copy number alteration, a mixed effects logistic regression model was used. The change in methylation between non-diseased tissues and their tumor counterparts was significantly greater in single compared to bidirectional promoters across all 14 cancer types examined. Similarly, the extent of copy number alteration was greater in single gene compared to bidirectional promoters for all 14 cancer types. Furthermore, among 10 cancer types with available simple somatic mutation data, bidirectional promoters were slightly more susceptible. These results suggest that selective pressures related with specific functional impacts during carcinogenesis drive the susceptibility of promoter regions to somatic alteration.
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Mokretar K, Pease D, Taanman JW, Soenmez A, Ejaz A, Lashley T, Ling H, Gentleman S, Houlden H, Holton JL, Schapira AHV, Nacheva E, Proukakis C. Somatic copy number gains of α-synuclein (SNCA) in Parkinson’s disease and multiple system atrophy brains. Brain 2018; 141:2419-2431. [DOI: 10.1093/brain/awy157] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 04/16/2018] [Indexed: 12/18/2022] Open
Affiliation(s)
- Katya Mokretar
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
- Department of Academic Haematology, University College London, UK
| | - Daniel Pease
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | - Jan-Willem Taanman
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | - Aynur Soenmez
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | - Ayesha Ejaz
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | - Tammaryn Lashley
- Queen Square Brain Bank for Neurodegenerative diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Helen Ling
- Queen Square Brain Bank for Neurodegenerative diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | | | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Janice L Holton
- Queen Square Brain Bank for Neurodegenerative diseases, Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Anthony H V Schapira
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
| | | | - Christos Proukakis
- Department of Clinical Neuroscience, UCL Institute of Neurology, University College London, London, UK
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Ouchia-Benissad S, Ladjali-Mohammedi K. Banding cytogenetics of the Barbary partridge Alectoris barbara and the Chukar partridge Alectoris chukar (Phasianidae): a large conservation with Domestic fowl Gallus domesticus revealed by high resolution chromosomes. COMPARATIVE CYTOGENETICS 2018; 12:171-199. [PMID: 29896323 PMCID: PMC5995975 DOI: 10.3897/compcytogen.v12i2.23743] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The development of avian cytogenetics is significantly behind that of mammals. In fact, since the advent of cytogenetic techniques, fewer than 1500 karyotypes have been established. The Barbary partridge Alectoris barbara Bonnaterre, 1790 is a bird of economic interest but its genome has not been studied so far. This species is endemic to North Africa and globally declining. The Chukar partridge Alectoris chukar Gray, 1830 is an introduced species which shares the same habitat area as the Barbary partridge and so there could be introgressive hybridisation. A cytogenetic study has been initiated in order to contribute to the Barbary partridge and the Chukar partridge genome analyses. The GTG, RBG and RHG-banded karyotypes of these species have been described. Primary fibroblast cell lines obtained from embryos were harvested after simple and double thymidine synchronisation. The first eight autosomal pairs and Z sex chromosome have been described at high resolution and compared to those of the domestic fowl Gallus domesticus Linnaeus, 1758. The diploid number was established as 2n = 78 for both partridges, as well as for most species belonging to the Galliformes order, underlying the stability of chromosome number in avian karyotypes. Wide homologies were observed for macrochromosomes and gonosome except for chromosome 4, 7, 8 and Z which present differences in morphology and/or banding pattern. Neocentromere occurrence was suggested for both partridges chromosome 4 with an assumed paracentric inversion in the Chukar partridge chromosome 4. Terminal inversion in the long arm of the Barbary partridge chromosome Z was also found. These rearrangements confirm that the avian karyotypes structure is conserved interchromosomally, but not at the intrachromosomal scale.
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Affiliation(s)
- Siham Ouchia-Benissad
- University of Sciences and Technology Houari Boumediene, Faculty of Biological Sciences, LBCM lab., Team: Genetics of Development. USTHB, PO box 32 El-Alia, Bab-Ezzouar, 16110 Algiers, Algeria
| | - Kafia Ladjali-Mohammedi
- University of Sciences and Technology Houari Boumediene, Faculty of Biological Sciences, LBCM lab., Team: Genetics of Development. USTHB, PO box 32 El-Alia, Bab-Ezzouar, 16110 Algiers, Algeria
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59
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da Silva VH, Laine VN, Bosse M, Oers KV, Dibbits B, Visser ME, M A Crooijmans RP, Groenen MAM. CNVs are associated with genomic architecture in a songbird. BMC Genomics 2018; 19:195. [PMID: 29703149 PMCID: PMC6389189 DOI: 10.1186/s12864-018-4577-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/02/2018] [Indexed: 12/11/2022] Open
Abstract
Background Understanding variation in genome structure is essential to understand phenotypic differences within populations and the evolutionary history of species. A promising form of this structural variation is copy number variation (CNV). CNVs can be generated by different recombination mechanisms, such as non-allelic homologous recombination, that rely on specific characteristics of the genome architecture. These structural variants can therefore be more abundant at particular genes ultimately leading to variation in phenotypes under selection. Detailed characterization of CNVs therefore can reveal evolutionary footprints of selection and provide insight in their contribution to phenotypic variation in wild populations. Results Here we use genotypic data from a long-term population of great tits (Parus major), a widely studied passerine bird in ecology and evolution, to detect CNVs and identify genomic features prevailing within these regions. We used allele intensities and frequencies from high-density SNP array data from 2,175 birds. We detected 41,029 CNVs concatenated into 8,008 distinct CNV regions (CNVRs). We successfully validated 93.75% of the CNVs tested by qPCR, which were sampled at different frequencies and sizes. A mother-daughter family structure allowed for the evaluation of the inheritance of a number of these CNVs. Thereby, only CNVs with 40 probes or more display segregation in accordance with Mendelian inheritance, suggesting a high rate of false negative calls for smaller CNVs. As CNVRs are a coarse-grained map of CNV loci, we also inferred the frequency of coincident CNV start and end breakpoints. We observed frequency-dependent enrichment of these breakpoints at homologous regions, CpG sites and AT-rich intervals. A gene ontology enrichment analyses showed that CNVs are enriched in genes underpinning neural, cardiac and ion transport pathways. Conclusion Great tit CNVs are present in almost half of the genes and prominent at repetitive-homologous and regulatory regions. Although overlapping genes under selection, the high number of false negatives make neutrality or association tests on CNVs detected here difficult. Therefore, CNVs should be further addressed in the light of their false negative rate and architecture to improve the comprehension of their association with phenotypes and evolutionary history. Electronic supplementary material The online version of this article (10.1186/s12864-018-4577-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vinicius H da Silva
- Animal Breeding and Genomics Centre, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands. .,Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708PB, The Netherlands.
| | - Veronika N Laine
- Animal Breeding and Genomics Centre, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands.,Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708PB, The Netherlands.,Swedish University of Agricultural Sciences (SLU), Ulls väg 26, Uppsala, 750 07, Sweden
| | - Mirte Bosse
- Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708PB, The Netherlands
| | - Kees van Oers
- Animal Breeding and Genomics Centre, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
| | - Bert Dibbits
- Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708PB, The Netherlands
| | - Marcel E Visser
- Animal Breeding and Genomics Centre, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
| | - Richard P M A Crooijmans
- Animal Breeding and Genomics Centre, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands.,Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, Wageningen, 6708PB, The Netherlands
| | - Martien A M Groenen
- Animal Breeding and Genomics Centre, Wageningen University & Research, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
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Abstract
A fragile site is a chromosomal locus that is prone to form a gap or constriction visible within a condensed metaphase chromosome, particularly following exposure of cells to DNA replication stress. Based on their frequency, fragile sites are classified as either common (CFSs; present in all individuals) or rare (RFSs; present in only a few individuals). Interest in fragile sites has remained high since their discovery in 1965, because of their association with human disease. CFSs are recognized as drivers of oncogene activation and genome instability in cancer cells, while some RFSs are associated with neurodegenerative diseases. This review summaries our current understanding of the nature and causes of fragile site "expression", including the recently characterized phenomenon of telomere fragility. In particular, we focus on a description of the methodologies and technologies for detection and analysis of chromosome fragile sites.
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Kim J, Sturgill D, Sebastian R, Khurana S, Tran AD, Edwards GB, Kruswick A, Burkett S, Hosogane EK, Hannon WW, Weyemi U, Bonner WM, Luger K, Oberdoerffer P. Replication Stress Shapes a Protective Chromatin Environment across Fragile Genomic Regions. Mol Cell 2017; 69:36-47.e7. [PMID: 29249653 DOI: 10.1016/j.molcel.2017.11.021] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 10/05/2017] [Accepted: 11/15/2017] [Indexed: 12/14/2022]
Abstract
Recent integrative epigenome analyses highlight the importance of functionally distinct chromatin states for accurate cell function. How these states are established and maintained is a matter of intense investigation. Here, we present evidence for DNA damage as an unexpected means to shape a protective chromatin environment at regions of recurrent replication stress (RS). Upon aberrant fork stalling, DNA damage signaling and concomitant H2AX phosphorylation coordinate the FACT-dependent deposition of macroH2A1.2, a histone variant that promotes DNA repair by homologous recombination (HR). MacroH2A1.2, in turn, facilitates the accumulation of the tumor suppressor and HR effector BRCA1 at replication forks to protect from RS-induced DNA damage. Consequently, replicating primary cells steadily accrue macroH2A1.2 at fragile regions, whereas macroH2A1.2 loss in these cells triggers DNA damage signaling-dependent senescence, a hallmark of RS. Altogether, our findings demonstrate that recurrent DNA damage contributes to the chromatin landscape to ensure the epigenomic integrity of dividing cells.
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Affiliation(s)
- Jeongkyu Kim
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - David Sturgill
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Robin Sebastian
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Simran Khurana
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Andy D Tran
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Garrett B Edwards
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Alex Kruswick
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Sandra Burkett
- Molecular Cytogenetics Core Facility, National Cancer Institute, NIH, Frederick, MD 21702, USA
| | - Eri K Hosogane
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - William W Hannon
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Urbain Weyemi
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - William M Bonner
- Developmental Therapeutics Branch, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Karolin Luger
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Philipp Oberdoerffer
- Laboratory of Receptor Biology and Gene Expression, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
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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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Zanon C, Tonini GP. Transcription instability in high-risk neuroblastoma is associated with a global perturbation of chromatin domains. Mol Oncol 2017; 11:1646-1658. [PMID: 28941026 PMCID: PMC5664000 DOI: 10.1002/1878-0261.12139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/07/2017] [Accepted: 09/13/2017] [Indexed: 12/16/2022] Open
Abstract
Chromosome instability has a pivotal role among the hallmarks of cancer, but its transcriptional counterpart is rarely considered a relevant factor in cell destabilization. To examine transcription instability (TIN), we first devised a metric we named TIN index and used it to evaluate TIN on a dataset containing more than 500 neuroblastoma samples. We found that metastatic tumors from high-risk (HR) patients are characterized by significantly different TIN index values compared to low/intermediate-risk patients. Our results indicate that the TIN index is a good predictor of neuroblastoma patient's outcome, and a related TIN index gene signature (TIN-signature) is also able to predict the neuroblastoma patient's outcome with high confidence. Interestingly, we find that TIN-signature genes have a strong positional association with superenhancers in neuroblastoma tumors. Finally, we show that TIN is linked to chromatin structural domains and interferes with their integrity in HR neuroblastoma patients. This novel approach to gene expression analysis broadens the perspective of genome instability investigations to include functional aspects.
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Affiliation(s)
- Carlo Zanon
- Neuroblastoma Laboratory, Pediatric Research Institute, Citta' della Speranza, Padua, Italy
| | - Gian Paolo Tonini
- Neuroblastoma Laboratory, Pediatric Research Institute, Citta' della Speranza, Padua, Italy
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DNA polymerases eta and kappa exchange with the polymerase delta holoenzyme to complete common fragile site synthesis. DNA Repair (Amst) 2017; 57:1-11. [PMID: 28605669 DOI: 10.1016/j.dnarep.2017.05.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/25/2017] [Accepted: 05/29/2017] [Indexed: 12/21/2022]
Abstract
Common fragile sites (CFSs) are inherently unstable genomic loci that are recurrently altered in human tumor cells. Despite their instability, CFS are ubiquitous throughout the human genome and associated with large tumor suppressor genes or oncogenes. CFSs are enriched with repetitive DNA sequences, one feature postulated to explain why these loci are inherently difficult to replicate, and sensitive to replication stress. We have shown that specialized DNA polymerases (Pols) η and κ replicate CFS-derived sequences more efficiently than the replicative Pol δ. However, we lacked an understanding of how these enzymes cooperate to ensure efficient CFS replication. Here, we designed a model of lagging strand replication with RFC loaded PCNA that allows for maximal activity of the four-subunit human Pol δ holoenzyme, Pol η, and Pol κ in polymerase mixing assays. We discovered that Pol η and κ are both able to exchange with Pol δ stalled at repetitive CFS sequences, enhancing Normalized Replication Efficiency. We used this model to test the impact of PCNA mono-ubiquitination on polymerase exchange, and found no change in polymerase cooperativity in CFS replication compared with unmodified PCNA. Finally, we modeled replication stress in vitro using aphidicolin and found that Pol δ holoenzyme synthesis was significantly inhibited in a dose-dependent manner, preventing any replication past the CFS. Importantly, Pol η and κ were still proficient in rescuing this stalled Pol δ synthesis, which may explain, in part, the CFS instability phenotype of aphidicolin-treated Pol η and Pol κ-deficient cells. In total, our data support a model wherein Pol δ stalling at CFSs allows for free exchange with a specialized polymerase that is not driven by PCNA.
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65
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Smida J, Xu H, Zhang Y, Baumhoer D, Ribi S, Kovac M, von Luettichau I, Bielack S, O'Leary VB, Leib-Mösch C, Frishman D, Nathrath M. Genome-wide analysis of somatic copy number alterations and chromosomal breakages in osteosarcoma. Int J Cancer 2017; 141:816-828. [DOI: 10.1002/ijc.30778] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/19/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Jan Smida
- Institute of Radiation Biology, Helmholtz Zentrum Munich - German Research Center for Environmental Health; Neuherberg Germany
- Clinical Cooperation Group Osteosarcoma, Helmholtz Zentrum Munich - German Research Center for Environmental Health; Neuherberg Germany
- Pediatric Oncology Center; Department of Pediatrics, Technical University of Munich and Comprehensive Cancer Center; Munich Germany
| | - Hongen Xu
- Department of Bioinformatics; Wissenschaftszentrum Weihenstephan, Technical University of Munich; Freising Germany
| | - Yanping Zhang
- Department of Bioinformatics; Wissenschaftszentrum Weihenstephan, Technical University of Munich; Freising Germany
| | - Daniel Baumhoer
- Bone Tumour Reference Center; Institute of Pathology, University Hospital Basel; Switzerland
| | - Sebastian Ribi
- Bone Tumour Reference Center; Institute of Pathology, University Hospital Basel; Switzerland
| | - Michal Kovac
- Bone Tumour Reference Center; Institute of Pathology, University Hospital Basel; Switzerland
| | - Irene von Luettichau
- Pediatric Oncology Center; Department of Pediatrics, Technical University of Munich and Comprehensive Cancer Center; Munich Germany
| | - Stefan Bielack
- Pediatrics 5 (Oncology, Hematology, Immunology), Klinikum Stuttgart Olgahospital; Stuttgart Germany
| | - Valerie B. O'Leary
- Institute of Radiation Biology, Helmholtz Zentrum Munich - German Research Center for Environmental Health; Neuherberg Germany
| | - Christine Leib-Mösch
- Institute of Virology, Helmholtz Zentrum Munich - German Research Center for Environmental Health; Neuherberg Germany
| | - Dmitrij Frishman
- Department of Bioinformatics; Wissenschaftszentrum Weihenstephan, Technical University of Munich; Freising Germany
- Institute of Bioinformatics and Systems Biology, Helmholtz Zentrum Munich - German Research Center for Environmental Health; Neuherberg Germany
- St Petersburg State Polytechnic University; St Petersburg Russia
| | - Michaela Nathrath
- Clinical Cooperation Group Osteosarcoma, Helmholtz Zentrum Munich - German Research Center for Environmental Health; Neuherberg Germany
- Pediatric Oncology Center; Department of Pediatrics, Technical University of Munich and Comprehensive Cancer Center; Munich Germany
- Department of Pediatric Hematology and Oncology; Klinikum Kassel; Germany
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66
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Bhowmick R, Hickson ID. The "enemies within": regions of the genome that are inherently difficult to replicate. F1000Res 2017; 6:666. [PMID: 28620461 PMCID: PMC5461909 DOI: 10.12688/f1000research.11024.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/11/2017] [Indexed: 12/23/2022] Open
Abstract
An unusual feature of many eukaryotic genomes is the presence of regions that appear intrinsically difficult to copy during the process of DNA replication. Curiously, the location of these difficult-to-replicate regions is often conserved between species, implying a valuable role in some aspect of genome organization or maintenance. The most prominent class of these regions in mammalian cells is defined as chromosome fragile sites, which acquired their name because of a propensity to form visible gaps/breaks on otherwise-condensed chromosomes in mitosis. This fragility is particularly apparent following perturbation of DNA replication-a phenomenon often referred to as "replication stress". Here, we review recent data on the molecular basis for chromosome fragility and the role of fragile sites in the etiology of cancer. In particular, we highlight how studies on fragile sites have provided unexpected insights into how the DNA repair machinery assists in the completion of DNA replication.
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Affiliation(s)
- Rahul Bhowmick
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
| | - Ian D Hickson
- Center for Chromosome Stability, Department of Cellular and Molecular Medicine, Panum Institute, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Denmark
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67
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Kawagoshi T, Shiomi N, Takahashi H, Watanabe Y, Fuma S, Doi K, Kawaguchi I, Aoki M, Kubota M, Furuhata Y, Shigemura Y, Mizoguchi M, Yamada F, Tomozawa M, Sakamoto SH, Yoshida S, Kubota Y. Chromosomal Aberrations in Large Japanese Field Mice (Apodemus speciosus) Captured near Fukushima Dai-ichi Nuclear Power Plant. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:4632-4641. [PMID: 28363014 DOI: 10.1021/acs.est.6b06210] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Since the Fukushima Dai-ichi Nuclear Power Plant accident, radiation effects on nonhuman biota in the contaminated areas have been a major concern. Here, we analyzed the frequencies of chromosomal aberrations (translocations and dicentrics) in the splenic lymphocytes of large Japanese field mice (Apodemus speciosus) inhabiting Fukushima Prefecture. A. speciosus chromosomes 1, 2, and 5 were flow-sorted in order to develop A. speciosus chromosome-specific painting probes, and FISH (fluorescence in situ hybridization) was performed using these painting probes to detect the translocations and dicentrics. The average frequency of the translocations and dicentrics per cell in the heavily contaminated area was significantly higher than the frequencies in the case of the noncontaminated control area and the slightly and moderately contaminated areas, and this aberration frequency in individual mice tended to roughly increase with the estimated dose rates and accumulated doses. In all four sampling areas, the proportion of aberrations occurring in chromosome 2 was approximately >3 times higher than that in chromosomes 1 and 5, which suggests that A. speciosus chromosome 2 harbors a fragile site that is highly sensitive to chromosome breaks induced by cellular stress such as DNA replication. The elevated frequency of chromosomal aberrations in A. speciosus potentially resulting from the presence of a fragile site in chromosome 2 might make it challenging to observe the mild effect of chronic low-dose-rate irradiation on the induction of chromosomal aberrations in A. speciosus inhabiting the contaminated areas of Fukushima.
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Affiliation(s)
- Taiki Kawagoshi
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Naoko Shiomi
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Hiroyuki Takahashi
- Tokyo Nuclear Services Co., Ltd. 1-3-5 Taito, Taito-ku, Tokyo 110-0016, Japan
| | - Yoshito Watanabe
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Shoichi Fuma
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kazutaka Doi
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Isao Kawaguchi
- Center for Radiation Protection Knowledge, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Masanari Aoki
- Japan Wildlife Research Center, 3-3-7 Koutoubashi, Sumida-ku, Tokyo 130-8606, Japan
| | - Masahide Kubota
- Japan Wildlife Research Center, 3-3-7 Koutoubashi, Sumida-ku, Tokyo 130-8606, Japan
| | - Yoshiaki Furuhata
- Japan Wildlife Research Center, 3-3-7 Koutoubashi, Sumida-ku, Tokyo 130-8606, Japan
| | - Yusaku Shigemura
- Japan NUS Co., Ltd, 7-5-25 Nishi-shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Masahiko Mizoguchi
- Japan NUS Co., Ltd, 7-5-25 Nishi-shinjuku, Shinjuku-ku, Tokyo 160-0023, Japan
| | - Fumio Yamada
- Forestry and Forest Products Research Institute , 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan
| | - Morihiko Tomozawa
- Department of Biology, Keio University , 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8521, Japan
| | - Shinsuke H Sakamoto
- Faculty of Agriculture, University of Miyazaki , Kibana Campus, Miyazaki 889-2192, Japan
| | - Satoshi Yoshida
- Department of Management and Planning, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yoshihisa Kubota
- Fukushima Project Headquarters, National Institute of Radiological Sciences, National Institute for Quantum and Radiological Science and Technology , 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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68
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Integration site selection by retroviruses and transposable elements in eukaryotes. Nat Rev Genet 2017; 18:292-308. [PMID: 28286338 DOI: 10.1038/nrg.2017.7] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transposable elements and retroviruses are found in most genomes, can be pathogenic and are widely used as gene-delivery and functional genomics tools. Exploring whether these genetic elements target specific genomic sites for integration and how this preference is achieved is crucial to our understanding of genome evolution, somatic genome plasticity in cancer and ageing, host-parasite interactions and genome engineering applications. High-throughput profiling of integration sites by next-generation sequencing, combined with large-scale genomic data mining and cellular or biochemical approaches, has revealed that the insertions are usually non-random. The DNA sequence, chromatin and nuclear context, and cellular proteins cooperate in guiding integration in eukaryotic genomes, leading to a remarkable diversity of insertion site distribution and evolutionary strategies.
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69
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Ssb1 and Ssb2 cooperate to regulate mouse hematopoietic stem and progenitor cells by resolving replicative stress. Blood 2017; 129:2479-2492. [PMID: 28270450 DOI: 10.1182/blood-2016-06-725093] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 02/26/2017] [Indexed: 12/14/2022] Open
Abstract
Hematopoietic stem and progenitor cells (HSPCs) are vulnerable to endogenous damage and defects in DNA repair can limit their function. The 2 single-stranded DNA (ssDNA) binding proteins SSB1 and SSB2 are crucial regulators of the DNA damage response; however, their overlapping roles during normal physiology are incompletely understood. We generated mice in which both Ssb1 and Ssb2 were constitutively or conditionally deleted. Constitutive Ssb1/Ssb2 double knockout (DKO) caused early embryonic lethality, whereas conditional Ssb1/Ssb2 double knockout (cDKO) in adult mice resulted in acute lethality due to bone marrow failure and intestinal atrophy featuring stem and progenitor cell depletion, a phenotype unexpected from the previously reported single knockout models of Ssb1 or Ssb2 Mechanistically, cDKO HSPCs showed altered replication fork dynamics, massive accumulation of DNA damage, genome-wide double-strand breaks enriched at Ssb-binding regions and CpG islands, together with the accumulation of R-loops and cytosolic ssDNA. Transcriptional profiling of cDKO HSPCs revealed the activation of p53 and interferon (IFN) pathways, which enforced cell cycling in quiescent HSPCs, resulting in their apoptotic death. The rapid cell death phenotype was reproducible in in vitro cultured cDKO-hematopoietic stem cells, which were significantly rescued by nucleotide supplementation or after depletion of p53. Collectively, Ssb1 and Ssb2 control crucial aspects of HSPC function, including proliferation and survival in vivo by resolving replicative stress to maintain genomic stability.
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70
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Madireddy A, Gerhardt J. Replication Through Repetitive DNA Elements and Their Role in Human Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:549-581. [PMID: 29357073 DOI: 10.1007/978-981-10-6955-0_23] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Human cells contain various repetitive DNA sequences, which can be a challenge for the DNA replication machinery to travel through and replicate correctly. Repetitive DNA sequence can adopt non-B DNA structures, which could block the DNA replication. Prolonged stalling of the replication fork at the endogenous repeats in human cells can have severe consequences such as genome instability that includes repeat expansions, contractions, and chromosome fragility. Several neurological and muscular diseases are caused by a repeat expansion. Furthermore genome instability is the major cause of cancer. This chapter describes some of the important classes of repetitive DNA sequences in the mammalian genome, their ability to form secondary DNA structures, their contribution to replication fork stalling, and models for repeat expansion as well as chromosomal fragility. Included in this chapter are also some of the strategies currently employed to detect changes in DNA replication and proteins that could prevent the repeat-mediated disruption of DNA replication in human cells. Additionally summarized are the consequences of repeat-associated perturbation of the DNA replication, which could lead to specific human diseases.
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71
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Feng W, Chakraborty A. Fragility Extraordinaire: Unsolved Mysteries of Chromosome Fragile Sites. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1042:489-526. [PMID: 29357071 DOI: 10.1007/978-981-10-6955-0_21] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chromosome fragile sites are a fascinating cytogenetic phenomenon now widely implicated in a slew of human diseases ranging from neurological disorders to cancer. Yet, the paths leading to these revelations were far from direct, and the number of fragile sites that have been molecularly cloned with known disease-associated genes remains modest. Moreover, as more fragile sites were being discovered, research interests in some of the earliest discovered fragile sites ebbed away, leaving a number of unsolved mysteries in chromosome biology. In this review we attempt to recount some of the early discoveries of fragile sites and highlight those phenomena that have eluded intense scrutiny but remain extremely relevant in our understanding of the mechanisms of chromosome fragility. We then survey the literature for disease association for a comprehensive list of fragile sites. We also review recent studies addressing the underlying cause of chromosome fragility while highlighting some ongoing debates. We report an observed enrichment for R-loop forming sequences in fragile site-associated genes than genomic average. Finally, we will leave the reader with some lingering questions to provoke discussion and inspire further scientific inquiries.
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Affiliation(s)
- Wenyi Feng
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA.
| | - Arijita Chakraborty
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
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72
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Zhao JW, Fang F, Guo Y, Zhu TL, Yu YY, Kong FF, Han LF, Chen DS, Li F. HPV16 integration probably contributes to cervical oncogenesis through interrupting tumor suppressor genes and inducing chromosome instability. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2016; 35:180. [PMID: 27884161 PMCID: PMC5123399 DOI: 10.1186/s13046-016-0454-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 11/09/2016] [Indexed: 12/11/2022]
Abstract
Background The integration of human papilloma virus (HPV) into host genome is one of the critical steps that lead to the progression of precancerous lesion into cancer. However, the mechanisms and consequences of such integration events are poorly understood. This study aims to explore those questions by studying high risk HPV16 integration in women with cervical intraepithelial neoplasia (CIN) and cervical squamous cell carcinoma (SCC). Methods Specifically, HPV integration status of 13 HPV16-infected patients were investigated by ligation-mediated PCR (DIPS-PCR) followed by DNA sequencing. Results In total, 8 HPV16 integration sites were identified inside or around genes associated with cancer development. In particular, the well-studied tumor suppressor genes SCAI was found to be integrated by HPV16, which would likely disrupt its expression and therefore facilitate the migration of tumor. On top of that, we observed several cases of chromosome translocation events coincide with HPV integration, which suggests the existence of chromosome instability. Additionally, short overlapping sequences were observed between viral derived and host derived fragments in viral-cellular junctions, indicating that integration was mediated by micro homology-mediated DNA repair pathway. Conclusions Overall, our study suggests a model in which HPV16 might contribute to oncogenesis not only by disrupting tumor suppressor genes, but also by inducing chromosome instability. Electronic supplementary material The online version of this article (doi:10.1186/s13046-016-0454-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jun-Wei Zhao
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Fang Fang
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Yi Guo
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Tai-Lin Zhu
- Abbey College Cambridge, Homerton Gardens, Cambridge, CB2 8EB, UK
| | - Yun-Yun Yu
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Fan-Fei Kong
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Ling-Fei Han
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Dong-Sheng Chen
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK. .,Fitzwilliam College, University of Cambridge, Storey's Way, Cambridge, CB3 0DG, UK.
| | - Fang Li
- Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China.
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73
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Saini N, Roberts SA, Klimczak LJ, Chan K, Grimm SA, Dai S, Fargo DC, Boyer JC, Kaufmann WK, Taylor JA, Lee E, Cortes-Ciriano I, Park PJ, Schurman SH, Malc EP, Mieczkowski PA, Gordenin DA. The Impact of Environmental and Endogenous Damage on Somatic Mutation Load in Human Skin Fibroblasts. PLoS Genet 2016; 12:e1006385. [PMID: 27788131 PMCID: PMC5082821 DOI: 10.1371/journal.pgen.1006385] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 09/23/2016] [Indexed: 12/24/2022] Open
Abstract
Accumulation of somatic changes, due to environmental and endogenous lesions, in the human genome is associated with aging and cancer. Understanding the impacts of these processes on mutagenesis is fundamental to understanding the etiology, and improving the prognosis and prevention of cancers and other genetic diseases. Previous methods relying on either the generation of induced pluripotent stem cells, or sequencing of single-cell genomes were inherently error-prone and did not allow independent validation of the mutations. In the current study we eliminated these potential sources of error by high coverage genome sequencing of single-cell derived clonal fibroblast lineages, obtained after minimal propagation in culture, prepared from skin biopsies of two healthy adult humans. We report here accurate measurement of genome-wide magnitude and spectra of mutations accrued in skin fibroblasts of healthy adult humans. We found that every cell contains at least one chromosomal rearrangement and 600–13,000 base substitutions. The spectra and correlation of base substitutions with epigenomic features resemble many cancers. Moreover, because biopsies were taken from body parts differing by sun exposure, we can delineate the precise contributions of environmental and endogenous factors to the accrual of genetic changes within the same individual. We show here that UV-induced and endogenous DNA damage can have a comparable impact on the somatic mutation loads in skin fibroblasts. Somatic genomes are constantly accumulating changes caused by endogenous lesions, errors in DNA replication and repair, as well as environmental insults. Despite the importance of somatic genome instability in aging and age-related pathologies, including cancers, accurate measurements of mutation loads in healthy cells is still missing. In this study, we developed an experimental approach to accurately determine the somatic genome changes accrued in cell lineages over the lifetime of healthy humans. We show that the amounts and types of mutations in skin cells resemble many cancers, thus indicating that the mechanisms that lead to carcinogenesis are also functional in healthy cells. Moreover, sun-exposed skin cells have a higher mutation load attributable to ultraviolet radiation (UV) unlike cells from hips that were protected by clothing. Our work provides precise measurements of the mutation loads in single cells in human skin. Furthermore our data allowed defining the mutagenic impacts of environmental and endogenous processes within the same individual and led to conclusion that these processes have a comparable impact on the somatic mutation load.
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Affiliation(s)
- Natalie Saini
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Steven A. Roberts
- School of Molecular Biosciences, Washington State University, Pullman, Washington, United States Of America
| | - Leszek J. Klimczak
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Kin Chan
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Sara A. Grimm
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Shuangshuang Dai
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - David C. Fargo
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Jayne C. Boyer
- Department of Environmental Science and Engineering, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - William K. Kaufmann
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - Jack A. Taylor
- Epidemiology Branch, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Eunjung Lee
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States Of America
- Division of Genetics, Brigham and Women’s Hospital, Boston, Massachusetts, United States Of America
| | - Isidro Cortes-Ciriano
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States Of America
| | - Peter J. Park
- Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States Of America
- Division of Genetics, Brigham and Women’s Hospital, Boston, Massachusetts, United States Of America
| | - Shepherd H. Schurman
- Clinical Research Unit, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
| | - Ewa P. Malc
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - Piotr A. Mieczkowski
- Department of Genetics, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, United States Of America
| | - Dmitry A. Gordenin
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Research Triangle Park, North Carolina, United States Of America
- * E-mail:
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74
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Superresolution intrinsic fluorescence imaging of chromatin utilizing native, unmodified nucleic acids for contrast. Proc Natl Acad Sci U S A 2016; 113:9716-21. [PMID: 27535934 DOI: 10.1073/pnas.1602202113] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Visualizing the nanoscale intracellular structures formed by nucleic acids, such as chromatin, in nonperturbed, structurally and dynamically complex cellular systems, will help expand our understanding of biological processes and open the next frontier for biological discovery. Traditional superresolution techniques to visualize subdiffractional macromolecular structures formed by nucleic acids require exogenous labels that may perturb cell function and change the very molecular processes they intend to study, especially at the extremely high label densities required for superresolution. However, despite tremendous interest and demonstrated need, label-free optical superresolution imaging of nucleotide topology under native nonperturbing conditions has never been possible. Here we investigate a photoswitching process of native nucleotides and present the demonstration of subdiffraction-resolution imaging of cellular structures using intrinsic contrast from unmodified DNA based on the principle of single-molecule photon localization microscopy (PLM). Using DNA-PLM, we achieved nanoscopic imaging of interphase nuclei and mitotic chromosomes, allowing a quantitative analysis of the DNA occupancy level and a subdiffractional analysis of the chromosomal organization. This study may pave a new way for label-free superresolution nanoscopic imaging of macromolecular structures with nucleotide topologies and could contribute to the development of new DNA-based contrast agents for superresolution imaging.
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75
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Kovtun IV, Murphy SJ, Johnson SH, Cheville JC, Vasmatzis G. Chromosomal catastrophe is a frequent event in clinically insignificant prostate cancer. Oncotarget 2016; 6:29087-96. [PMID: 26337081 PMCID: PMC4745713 DOI: 10.18632/oncotarget.4900] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/11/2015] [Indexed: 11/27/2022] Open
Abstract
Massive genomic rearrangements, a result of single catastrophic event termed chromothrispsis or chromosomal catastrophe, have been identified in a variety of human cancers. In a few cancer types, chromothripsis was found to be associated with poor prognosis. We performed mate-pair sequencing and analysis of structural rearrangements in 132 prostate cancer cases which included clinically insignificant Gleason score 6 tumors, clinically significant tumors of higher grade (7+) and high grade prostatic intraepithelial neoplasia. Chromothripsis was observed at least 30 per cent of the samples across different grades. Surprisingly, it was frequently observed in clinically insignificant Gleason score 6 tumors, indicating that chromothripsis does not define more aggressive phenotype. The degree of chromothripsis did not increase significantly in tumors of advanced grades and did not appear to contribute to tumor progression. Our data showed that distribution of chromothriptic rearrangements differed from that of fragile sites but correlated with the size of chromosomes. We also provided evidence that rearrangements resulting from chromothripsis were present in the cells of neighboring Gleason patterns of the same tumor. Our data suggest that that chromothripsis plays role in prostate cancer initiation.
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Affiliation(s)
- Irina V Kovtun
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota, USA.,Department of Center of Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Stephen J Murphy
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Center of Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Sarah H Johnson
- Department of Center of Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - John C Cheville
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA.,Department of Center of Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - George Vasmatzis
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Center of Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA
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76
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Survival control of malignant lymphocytes by anti-apoptotic MCL-1. Leukemia 2016; 30:2152-2159. [PMID: 27479182 DOI: 10.1038/leu.2016.213] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/24/2016] [Accepted: 07/04/2016] [Indexed: 02/07/2023]
Abstract
Programmed apoptotic cell death is critical to maintain tissue homeostasis and cellular integrity in the lymphatic system. Accordingly, the evasion of apoptosis is a critical milestone for the transformation of lymphocytes on their way to becoming overt lymphomas. The anti-apoptotic BCL-2 family proteins are pivotal regulators of the mitochondrial apoptotic pathway and genetic aberrations in these genes are associated with lymphomagenesis and chemotherapeutic resistance. Pharmacological targeting of BCL-2 is highly effective in certain indolent B-cell lymphomas; however, recent evidence highlights a critical role for the BCL-2 family member MCL-1 in several lymphoma subtypes. MCL-1 is recurrently highly expressed in various kinds of cancer including non-Hodgkin's lymphoma of B- and T-cell origin. Moreover, both indolent and aggressive forms of lymphoma require MCL-1 for lymphomagenesis and for their continued survival. This review summarizes the role of MCL-1 in B- and T-cell lymphoma and discusses its potential as a therapeutic target.
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77
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RUBIC identifies driver genes by detecting recurrent DNA copy number breaks. Nat Commun 2016; 7:12159. [PMID: 27396759 PMCID: PMC4942583 DOI: 10.1038/ncomms12159] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 06/07/2016] [Indexed: 01/12/2023] Open
Abstract
The frequent recurrence of copy number aberrations across tumour samples is a reliable hallmark of certain cancer driver genes. However, state-of-the-art algorithms for detecting recurrent aberrations fail to detect several known drivers. In this study, we propose RUBIC, an approach that detects recurrent copy number breaks, rather than recurrently amplified or deleted regions. This change of perspective allows for a simplified approach as recursive peak splitting procedures and repeated re-estimation of the background model are avoided. Furthermore, we control the false discovery rate on the level of called regions, rather than at the probe level, as in competing algorithms. We benchmark RUBIC against GISTIC2 (a state-of-the-art approach) and RAIG (a recently proposed approach) on simulated copy number data and on three SNP6 and NGS copy number data sets from TCGA. We show that RUBIC calls more focal recurrent regions and identifies a much larger fraction of known cancer genes. Analysis of cancer genome sequencing data has been used to predict genes associated with the pathogenesis of cancer. Here, the authors propose a new algorithm entitled RUBIC that predicts breaks in DNA as opposed to previously published methods that predict amplifications and deletions of DNA.
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78
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Campos-Sánchez R, Cremona MA, Pini A, Chiaromonte F, Makova KD. Integration and Fixation Preferences of Human and Mouse Endogenous Retroviruses Uncovered with Functional Data Analysis. PLoS Comput Biol 2016; 12:e1004956. [PMID: 27309962 PMCID: PMC4911145 DOI: 10.1371/journal.pcbi.1004956] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 04/29/2016] [Indexed: 01/24/2023] Open
Abstract
Endogenous retroviruses (ERVs), the remnants of retroviral infections in the germ line, occupy ~8% and ~10% of the human and mouse genomes, respectively, and affect their structure, evolution, and function. Yet we still have a limited understanding of how the genomic landscape influences integration and fixation of ERVs. Here we conducted a genome-wide study of the most recently active ERVs in the human and mouse genome. We investigated 826 fixed and 1,065 in vitro HERV-Ks in human, and 1,624 fixed and 242 polymorphic ETns, as well as 3,964 fixed and 1,986 polymorphic IAPs, in mouse. We quantitated >40 human and mouse genomic features (e.g., non-B DNA structure, recombination rates, and histone modifications) in ±32 kb of these ERVs' integration sites and in control regions, and analyzed them using Functional Data Analysis (FDA) methodology. In one of the first applications of FDA in genomics, we identified genomic scales and locations at which these features display their influence, and how they work in concert, to provide signals essential for integration and fixation of ERVs. The investigation of ERVs of different evolutionary ages (young in vitro and polymorphic ERVs, older fixed ERVs) allowed us to disentangle integration vs. fixation preferences. As a result of these analyses, we built a comprehensive model explaining the uneven distribution of ERVs along the genome. We found that ERVs integrate in late-replicating AT-rich regions with abundant microsatellites, mirror repeats, and repressive histone marks. Regions favoring fixation are depleted of genes and evolutionarily conserved elements, and have low recombination rates, reflecting the effects of purifying selection and ectopic recombination removing ERVs from the genome. In addition to providing these biological insights, our study demonstrates the power of exploiting multiple scales and localization with FDA. These powerful techniques are expected to be applicable to many other genomic investigations.
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Affiliation(s)
- Rebeca Campos-Sánchez
- Genetics Graduate Program, The Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania, United States of America
| | - Marzia A. Cremona
- MOX—Modeling and Scientific Computing, Department of Mathematics, Politecnico di Milano, Milano, Italy
- Department of Statistics, Penn State University, University Park, Pennsylvania, United States of America
| | - Alessia Pini
- MOX—Modeling and Scientific Computing, Department of Mathematics, Politecnico di Milano, Milano, Italy
| | - Francesca Chiaromonte
- Department of Statistics, Penn State University, University Park, Pennsylvania, United States of America
- Center for Medical Genomics, The Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania, United States of America
| | - Kateryna D. Makova
- Center for Medical Genomics, The Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania, United States of America
- Department of Biology, Penn State University, University Park, Pennsylvania, United States of America
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79
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McGuire AB, Rafi SK, Manzardo AM, Butler MG. Morphometric Analysis of Recognized Genes for Autism Spectrum Disorders and Obesity in Relationship to the Distribution of Protein-Coding Genes on Human Chromosomes. Int J Mol Sci 2016; 17:E673. [PMID: 27164088 PMCID: PMC4881499 DOI: 10.3390/ijms17050673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/11/2016] [Accepted: 04/28/2016] [Indexed: 12/20/2022] Open
Abstract
Mammalian chromosomes are comprised of complex chromatin architecture with the specific assembly and configuration of each chromosome influencing gene expression and function in yet undefined ways by varying degrees of heterochromatinization that result in Giemsa (G) negative euchromatic (light) bands and G-positive heterochromatic (dark) bands. We carried out morphometric measurements of high-resolution chromosome ideograms for the first time to characterize the total euchromatic and heterochromatic chromosome band length, distribution and localization of 20,145 known protein-coding genes, 790 recognized autism spectrum disorder (ASD) genes and 365 obesity genes. The individual lengths of G-negative euchromatin and G-positive heterochromatin chromosome bands were measured in millimeters and recorded from scaled and stacked digital images of 850-band high-resolution ideograms supplied by the International Society of Chromosome Nomenclature (ISCN) 2013. Our overall measurements followed established banding patterns based on chromosome size. G-negative euchromatic band regions contained 60% of protein-coding genes while the remaining 40% were distributed across the four heterochromatic dark band sub-types. ASD genes were disproportionately overrepresented in the darker heterochromatic sub-bands, while the obesity gene distribution pattern did not significantly differ from protein-coding genes. Our study supports recent trends implicating genes located in heterochromatin regions playing a role in biological processes including neurodevelopment and function, specifically genes associated with ASD.
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Affiliation(s)
| | | | - Ann M Manzardo
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS 66160, USA.
| | - Merlin G Butler
- Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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80
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Bacolla A, Tainer JA, Vasquez KM, Cooper DN. Translocation and deletion breakpoints in cancer genomes are associated with potential non-B DNA-forming sequences. Nucleic Acids Res 2016; 44:5673-88. [PMID: 27084947 PMCID: PMC4937311 DOI: 10.1093/nar/gkw261] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 03/30/2016] [Indexed: 12/13/2022] Open
Abstract
Gross chromosomal rearrangements (including translocations, deletions, insertions and duplications) are a hallmark of cancer genomes and often create oncogenic fusion genes. An obligate step in the generation of such gross rearrangements is the formation of DNA double-strand breaks (DSBs). Since the genomic distribution of rearrangement breakpoints is non-random, intrinsic cellular factors may predispose certain genomic regions to breakage. Notably, certain DNA sequences with the potential to fold into secondary structures [potential non-B DNA structures (PONDS); e.g. triplexes, quadruplexes, hairpin/cruciforms, Z-DNA and single-stranded looped-out structures with implications in DNA replication and transcription] can stimulate the formation of DNA DSBs. Here, we tested the postulate that these DNA sequences might be found at, or in close proximity to, rearrangement breakpoints. By analyzing the distribution of PONDS-forming sequences within ±500 bases of 19 947 translocation and 46 365 sequence-characterized deletion breakpoints in cancer genomes, we find significant association between PONDS-forming repeats and cancer breakpoints. Specifically, (AT)n, (GAA)n and (GAAA)n constitute the most frequent repeats at translocation breakpoints, whereas A-tracts occur preferentially at deletion breakpoints. Translocation breakpoints near PONDS-forming repeats also recur in different individuals and patient tumor samples. Hence, PONDS-forming sequences represent an intrinsic risk factor for genomic rearrangements in cancer genomes.
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Affiliation(s)
- Albino Bacolla
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Ave., Houston, TX 77030, USA Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, 6767 Bertner Ave., Houston, TX 77030, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, 1400 Barbara Jordan Blvd., Austin, TX 78723, USA
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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81
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Konkel MK, Ullmer B, Arceneaux EL, Sanampudi S, Brantley SA, Hubley R, Smit AFA, Batzer MA. Discovery of a new repeat family in the Callithrix jacchus genome. Genome Res 2016; 26:649-59. [PMID: 26916108 PMCID: PMC4864456 DOI: 10.1101/gr.199075.115] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/23/2016] [Indexed: 11/24/2022]
Abstract
We identified a novel repeat family, termed Platy-1, in the Callithrix jacchus (common marmoset) genome that arose around the time of the divergence of platyrrhines and catarrhines and established itself as a repeat family in New World monkeys (NWMs). A full-length Platy-1 element is ∼100 bp in length, making it the shortest known short interspersed element (SINE) in primates, and harbors features characteristic of non-LTR retrotransposons. We identified 2268 full-length Platy-1 elements across 62 subfamilies in the common marmoset genome. Our subfamily reconstruction and phylogenetic analyses support Platy-1 propagation throughout the evolution of NWMs in the lineage leading to C. jacchus Platy-1 appears to have reached its amplification peak in the common ancestor of current day marmosets and has since moderately declined. However, identification of more than 200 Platy-1 elements identical to their respective consensus sequence, and the presence of polymorphic elements within common marmoset populations, suggests ongoing retrotransposition activity. Platy-1, a SINE, appears to have originated from an Alu element, and hence is likely derived from 7SL RNA. Our analyses illustrate the birth of a new repeat family and its propagation dynamics in the lineage leading to the common marmoset over the last 40 million years.
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Affiliation(s)
- Miriam K Konkel
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Brygg Ullmer
- School of Electrical Engineering and Computer Science, Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Erika L Arceneaux
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Sreeja Sanampudi
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Sarah A Brantley
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Robert Hubley
- Institute for Systems Biology, Seattle, Washington 98109-5263, USA
| | - Arian F A Smit
- Institute for Systems Biology, Seattle, Washington 98109-5263, USA
| | - Mark A Batzer
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, USA
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Whole-Genome Sequencing Reveals Diverse Models of Structural Variations in Esophageal Squamous Cell Carcinoma. Am J Hum Genet 2016; 98:256-74. [PMID: 26833333 PMCID: PMC4746371 DOI: 10.1016/j.ajhg.2015.12.013] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 12/15/2015] [Indexed: 01/02/2023] Open
Abstract
Comprehensive identification of somatic structural variations (SVs) and understanding their mutational mechanisms in cancer might contribute to understanding biological differences and help to identify new therapeutic targets. Unfortunately, characterization of complex SVs across the whole genome and the mutational mechanisms underlying esophageal squamous cell carcinoma (ESCC) is largely unclear. To define a comprehensive catalog of somatic SVs, affected target genes, and their underlying mechanisms in ESCC, we re-analyzed whole-genome sequencing (WGS) data from 31 ESCCs using Meerkat algorithm to predict somatic SVs and Patchwork to determine copy-number changes. We found deletions and translocations with NHEJ and alt-EJ signature as the dominant SV types, and 16% of deletions were complex deletions. SVs frequently led to disruption of cancer-associated genes (e.g., CDKN2A and NOTCH1) with different mutational mechanisms. Moreover, chromothripsis, kataegis, and breakage-fusion-bridge (BFB) were identified as contributing to locally mis-arranged chromosomes that occurred in 55% of ESCCs. These genomic catastrophes led to amplification of oncogene through chromothripsis-derived double-minute chromosome formation (e.g., FGFR1 and LETM2) or BFB-affected chromosomes (e.g., CCND1, EGFR, ERBB2, MMPs, and MYC), with approximately 30% of ESCCs harboring BFB-derived CCND1 amplification. Furthermore, analyses of copy-number alterations reveal high frequency of whole-genome duplication (WGD) and recurrent focal amplification of CDCA7 that might act as a potential oncogene in ESCC. Our findings reveal molecular defects such as chromothripsis and BFB in malignant transformation of ESCCs and demonstrate diverse models of SVs-derived target genes in ESCCs. These genome-wide SV profiles and their underlying mechanisms provide preventive, diagnostic, and therapeutic implications for ESCCs.
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83
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Ohtsuka Y, Higashimoto K, Oka T, Yatsuki H, Jozaki K, Maeda T, Kawahara K, Hamasaki Y, Matsuo M, Nishioka K, Joh K, Mukai T, Soejima H. Identification of consensus motifs associated with mitotic recombination and clinical characteristics in patients with paternal uniparental isodisomy of chromosome 11. Hum Mol Genet 2016; 25:1406-19. [PMID: 26908620 DOI: 10.1093/hmg/ddw023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 01/25/2016] [Indexed: 11/14/2022] Open
Abstract
Uniparental disomy (UPD) is defined as the inheritance of both homologs of a given genomic region from only one parent. The majority of UPD includes an entire chromosome. However, the extent of UPD is sometimes limited to a subchromosomal region (segmental UPD). Mosaic paternal UPD (pUPD) of chromosome 11 is found in approximately 20% of patients with Beckwith-Wiedemann syndrome (BWS) and almost all pUPDs are segmental isodisomic pUPDs resulting from mitotic recombination at an early embryonic stage. A mechanism initiating a DNA double strand break (DSB) within 11p has been predicted to lead to segmental pUPD. However, no consensus motif has yet been found. Here, we analyzed 32 BWS patients with pUPD by SNP array and searched for consensus motifs. We identified four consensus motifs frequently appearing within breakpoint regions of segmental pUPD. These motifs were found in another nine BWS patients with pUPD. In addition, the seven motifs found in meiotic recombination hot spots could not be found within pUPD breakpoint regions. Histone H3 lysine 4 trimethylation, a marker of DSB initiation, could not be found either. These findings suggest that the mechanism(s) of mitotic recombination leading to segmental pUPD are different from that of meiotic recombination. Furthermore, we found seven patients with paternal uniparental diploidy (PUD) mosaicism. Comparison of clinical features between segmental pUPDs and PUDs showed that developmental disability and cardiac abnormalities were additional characteristic features of PUD mosaicism, along with high risk of tumor development. We also found that macroglossia was characteristic of segmental pUPD mosaicism.
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Affiliation(s)
- Yasufumi Ohtsuka
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine, Department of Pediatrics, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Ken Higashimoto
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine
| | - Takehiko Oka
- World Fusion Co., Ltd., Tokyo 103-0013, Japan and
| | - Hitomi Yatsuki
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine
| | - Kosuke Jozaki
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine
| | - Toshiyuki Maeda
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine, Department of Pediatrics, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | | | - Yuhei Hamasaki
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Muneaki Matsuo
- Department of Pediatrics, Faculty of Medicine, Saga University, Saga 849-8501, Japan
| | - Kenichi Nishioka
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine
| | - Keiichiro Joh
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine
| | | | - Hidenobu Soejima
- Division of Molecular Genetics and Epigenetics, Department of Biomolecular Sciences, Faculty of Medicine,
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84
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Knouse KA, Wu J, Amon A. Assessment of megabase-scale somatic copy number variation using single-cell sequencing. Genome Res 2016; 26:376-84. [PMID: 26772196 PMCID: PMC4772019 DOI: 10.1101/gr.198937.115] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 01/14/2016] [Indexed: 11/25/2022]
Abstract
Megabase-scale copy number variants (CNVs) can have profound phenotypic consequences. Germline CNVs of this magnitude are associated with disease and experience negative selection. However, it is unknown whether organismal function requires that every cell maintain a balanced genome. It is possible that large somatic CNVs are tolerated or even positively selected. Single-cell sequencing is a useful tool for assessing somatic genomic heterogeneity, but its performance in CNV detection has not been rigorously tested. Here, we develop an approach that allows for reliable detection of megabase-scale CNVs in single somatic cells. We discover large CNVs in 8%–9% of cells across tissues and identify two recurrent CNVs. We conclude that large CNVs can be tolerated in subpopulations of cells, and particular CNVs are relatively prevalent within and across individuals.
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Affiliation(s)
- Kristin A Knouse
- Koch Institute for Integrative Cancer Research, Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Division of Health Sciences and Technology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jie Wu
- The Barbara K. Ostrom (1978) Bioinformatics and Computing Facility in the Swanson Biotechnology Center, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Angelika Amon
- Koch Institute for Integrative Cancer Research, Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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85
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Zhang Y, Xu H, Frishman D. Genomic determinants of somatic copy number alterations across human cancers. Hum Mol Genet 2016; 25:1019-30. [DOI: 10.1093/hmg/ddv623] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 12/21/2015] [Indexed: 01/03/2023] Open
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86
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Donigan KA, Cerritelli SM, McDonald JP, Vaisman A, Crouch RJ, Woodgate R. Unlocking the steric gate of DNA polymerase η leads to increased genomic instability in Saccharomyces cerevisiae. DNA Repair (Amst) 2015; 35:1-12. [PMID: 26340535 PMCID: PMC4651834 DOI: 10.1016/j.dnarep.2015.07.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/18/2015] [Accepted: 07/21/2015] [Indexed: 11/26/2022]
Abstract
DNA polymerase η (pol η) is best characterized for its ability to perform accurate and efficient translesion DNA synthesis (TLS) through cyclobutane pyrimidine dimers (CPDs). To ensure accurate bypass the polymerase is not only required to select the correct base, but also discriminate between NTPs and dNTPs. Most DNA polymerases have a conserved "steric gate" residue which functions to prevent incorporation of NMPs during DNA synthesis. Here, we demonstrate that the Phe35 residue of Saccharomyces cerevisiae pol η functions as a steric gate to limit the use of ribonucleotides during polymerization both in vitro and in vivo. Unlike the related pol ι enzyme, wild-type pol η does not readily incorporate NMPs in vitro. In contrast, a pol η F35A mutant incorporates NMPs on both damaged and undamaged DNA in vitro with a high degree of base selectivity. An S.cerevisiae strain expressing pol η F35A (rad30-F35A) that is also deficient for nucleotide excision repair (rad1Δ) and the TLS polymerase, pol ζ (rev3Δ), is extremely sensitive to UV-light. The sensitivity is due, in part, to RNase H2 activity, as an isogenic rnh201Δ strain is roughly 50-fold more UV-resistant than its RNH201(+) counterpart. Interestingly the rad1Δ rev3Δ rad30-F35A rnh201Δ strain exhibits a significant increase in the extent of spontaneous mutagenesis with a spectrum dominated by 1bp deletions at runs of template Ts. We hypothesize that the increased mutagenesis is due to rA incorporation at these sites and that the short poly rA tract is subsequently repaired in an error-prone manner by a novel repair pathway that is specifically targeted to polyribonucleotide tracks. These data indicate that under certain conditions, pol η can compete with the cell's replicases and gain access to undamaged genomic DNA. Such observations are consistent with a role for pol η in replicating common fragile sites (CFS) in human cells.
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Affiliation(s)
- Katherine A Donigan
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Susana M Cerritelli
- Program in Genomics of Differentiation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - John P McDonald
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Alexandra Vaisman
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA
| | - Robert J Crouch
- Program in Genomics of Differentiation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, USA.
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87
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Fan X, Supiwong W, Weise A, Mrasek K, Kosyakova N, Tanomtong A, Pinthong K, Trifonov VA, Cioffi MDB, Grothmann P, Liehr T, Oliveira EH. Comprehensive characterization of evolutionary conserved breakpoints in four New World Monkey karyotypes compared to Chlorocebus aethiops and Homo sapiens. Heliyon 2015; 1:e00042. [PMID: 27441227 PMCID: PMC4945616 DOI: 10.1016/j.heliyon.2015.e00042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 11/21/2022] Open
Abstract
Comparative cytogenetic analysis in New World Monkeys (NWMs) using human multicolor banding (MCB) probe sets were not previously done. Here we report on an MCB based FISH-banding study complemented with selected locus-specific and heterochromatin specific probes in four NWMs and one Old World Monkey (OWM) species, i.e. in Alouatta caraya (ACA), Callithrix jacchus (CJA), Cebus apella (CAP), Saimiri sciureus (SSC), and Chlorocebus aethiops (CAE), respectively. 107 individual evolutionary conserved breakpoints (ECBs) among those species were identified and compared with those of other species in previous reports. Especially for chromosomal regions being syntenic to human chromosomes 6, 8, 9, 10, 11, 12 and 16 previously cryptic rearrangements could be observed. 50.4% (54/107) NWM-ECBs were colocalized with those of OWMs, 62.6% (62/99) NWM-ECBs were related with those of Hylobates lar (HLA) and 66.3% (71/107) NWM-ECBs corresponded with those known from other mammalians. Furthermore, human fragile sites were aligned with the ECBs found in the five studied species and interestingly 66.3% ECBs colocalized with those fragile sites (FS). Overall, this study presents detailed chromosomal maps of one OWM and four NWM species. This data will be helpful to further investigation on chromosome evolution in NWM and hominoids in general and is prerequisite for correct interpretation of future sequencing based genomic studies in those species.
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Key Words
- ACA, Alouatta caraya
- Atelidae
- BACs, bacterial artificial chromosomes
- CAE, Chlorocebus aethiops
- CAP, Cebus apella
- CJA, Callithrix jacchus
- Cebidae
- EC, evolutionary conserved
- ECBs, evolutionary conserved breakpoints
- Evolutionary conserved breakpoints
- Evolutionary genetics
- FISH, fluorescence in situ hybridization
- FS, fragile site
- Fragile sites
- Genetics
- HCM, heterochromatin mix
- HLA, Hylobates lar
- HSA, Homo sapiens
- HSBs, homologous syntenic blocks
- MCB, multicolor banding
- Multicolor banding
- NGS, Next-generation sequencing
- NOR, nucleolus organizer region
- NWMs, New World Monkeys
- New World Monkeys
- OWMs, Old World Monkeys
- Old World Monkeys
- SSC, Saimiri sciureus
- subCTM, sub-centromere/subtelomere-specific multicolor (FISH)
- wcp, whole human chromosome painting
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Affiliation(s)
- Xiaobo Fan
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, D-07743 Jena, Germany
| | - Weerayuth Supiwong
- Department of Biology Faculty of Science, KhonKaen University, 123 Moo 16 Mittapap Rd., Muang District, KhonKaen 40002, Thailand
| | - Anja Weise
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, D-07743 Jena, Germany
| | - Kristin Mrasek
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, D-07743 Jena, Germany
| | - Nadezda Kosyakova
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, D-07743 Jena, Germany
| | - Alongkoad Tanomtong
- Department of Biology Faculty of Science, KhonKaen University, 123 Moo 16 Mittapap Rd., Muang District, KhonKaen 40002, Thailand
| | - Krit Pinthong
- Department of Biology Faculty of Science, KhonKaen University, 123 Moo 16 Mittapap Rd., Muang District, KhonKaen 40002, Thailand
| | | | - Marcelo de Bello Cioffi
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, SP, Brazil
| | - Pierre Grothmann
- Serengeti-Park Hodenhagen GmbH, Am Safaripark 1, 29693, Hodenhagen, Germany
| | - Thomas Liehr
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, D-07743 Jena, Germany
| | - Edivaldo H.C.de Oliveira
- Faculdade de Ciências Naturais, ICEN, Universidade Federal do Pará, Campus Universitário do Guamá, 66075-110 Belém-PA, Brazil
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88
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Kumari D, Hayward B, Nakamura AJ, Bonner WM, Usdin K. Evidence for chromosome fragility at the frataxin locus in Friedreich ataxia. Mutat Res 2015; 781:14-21. [PMID: 26379101 PMCID: PMC4631761 DOI: 10.1016/j.mrfmmm.2015.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/14/2015] [Accepted: 08/27/2015] [Indexed: 11/18/2022]
Abstract
Friedreich ataxia (FRDA) is a member of the Repeat Expansion Diseases, a group of genetic conditions resulting from an increase/expansion in the size of a specific tandem array. FRDA results from expansion of a GAA/TTC-tract in the first intron of the frataxin gene (FXN). The disease-associated tandem repeats all form secondary structures that are thought to contribute to the propensity of the repeat to expand. The subset of these diseases that result from a CGG/CCG-repeat expansion, such as Fragile X syndrome, also express a folate-sensitive fragile site coincident with the repeat on the affected chromosome. This chromosome fragility involves the generation of chromosome/chromatid gaps or breaks, or the high frequency loss of one or both copies of the affected gene when cells are grown under folate stress or as we showed previously, in the presence of an inhibitor of the ATM checkpoint kinase. Whether Repeat Expansion Disease loci containing different repeats form similar fragile sites was not known. We show here that the region of chromosome 9 that contains the FXN locus is intrinsically prone to breakage in vivo even in control cells. However, like FXS alleles, FRDA alleles show significantly elevated levels of chromosome abnormalities in the presence of an ATM inhibitor, consistent with the formation of a fragile site.
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Affiliation(s)
- Daman Kumari
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bruce Hayward
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Asako J Nakamura
- Laboratory of Molecular Pharmacology, CCR, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - William M Bonner
- Laboratory of Molecular Pharmacology, CCR, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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89
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Replication stress in Mammalian cells and its consequences for mitosis. Genes (Basel) 2015; 6:267-98. [PMID: 26010955 PMCID: PMC4488665 DOI: 10.3390/genes6020267] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/15/2015] [Accepted: 05/18/2015] [Indexed: 12/23/2022] Open
Abstract
The faithful transmission of genetic information to daughter cells is central to maintaining genomic stability and relies on the accurate and complete duplication of genetic material during each cell cycle. However, the genome is routinely exposed to endogenous and exogenous stresses that can impede the progression of replication. Such replication stress can be an early cause of cancer or initiate senescence. Replication stress, which primarily occurs during S phase, results in consequences during mitosis, jeopardizing chromosome segregation and, in turn, genomic stability. The traces of replication stress can be detected in the daughter cells during G1 phase. Alterations in mitosis occur in two types: 1) local alterations that correspond to breaks, rearrangements, intertwined DNA molecules or non-separated sister chromatids that are confined to the region of the replication dysfunction; 2) genome-wide chromosome segregation resulting from centrosome amplification (although centrosomes do not contain DNA), which amplifies the local replication stress to the entire genome. Here, we discuss the endogenous causes of replication perturbations, the mechanisms of replication fork restart and the consequences for mitosis, chromosome segregation and genomic stability.
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90
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Thys RG, Lehman CE, Pierce LCT, Wang YH. DNA secondary structure at chromosomal fragile sites in human disease. Curr Genomics 2015; 16:60-70. [PMID: 25937814 PMCID: PMC4412965 DOI: 10.2174/1389202916666150114223205] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 11/22/2022] Open
Abstract
DNA has the ability to form a variety of secondary structures that can interfere with normal cellular processes, and many of these structures have been associated with neurological diseases and cancer. Secondary structure-forming sequences are often found at chromosomal fragile sites, which are hotspots for sister chromatid exchange, chromosomal translocations, and deletions. Structures formed at fragile sites can lead to instability by disrupting normal cellular processes such as DNA replication and transcription. The instability caused by disruption of replication and transcription can lead to DNA breakage, resulting in gene rearrangements and deletions that cause disease. In this review, we discuss the role of DNA secondary structure at fragile sites in human disease.
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Affiliation(s)
- Ryan G Thys
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA
| | - Christine E Lehman
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157, USA
| | | | - Yuh-Hwa Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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91
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Menconi G, Bedini A, Barale R, Sbrana I. Global mapping of DNA conformational flexibility on Saccharomyces cerevisiae. PLoS Comput Biol 2015; 11:e1004136. [PMID: 25860149 PMCID: PMC4393290 DOI: 10.1371/journal.pcbi.1004136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/16/2015] [Indexed: 11/25/2022] Open
Abstract
In this study we provide the first comprehensive map of DNA conformational flexibility in Saccharomyces cerevisiae complete genome. Flexibility plays a key role in DNA supercoiling and DNA/protein binding, regulating DNA transcription, replication or repair. Specific interest in flexibility analysis concerns its relationship with human genome instability. Enrichment in flexible sequences has been detected in unstable regions of human genome defined fragile sites, where genes map and carry frequent deletions and rearrangements in cancer. Flexible sequences have been suggested to be the determinants of fragile gene proneness to breakage; however, their actual role and properties remain elusive. Our in silico analysis carried out genome-wide via the StabFlex algorithm, shows the conserved presence of highly flexible regions in budding yeast genome as well as in genomes of other Saccharomyces sensu stricto species. Flexibile peaks in S. cerevisiae identify 175 ORFs mapping on their 3'UTR, a region affecting mRNA translation, localization and stability. (TA)n repeats of different extension shape the central structure of peaks and co-localize with polyadenylation efficiency element (EE) signals. ORFs with flexible peaks share common features. Transcripts are characterized by decreased half-life: this is considered peculiar of genes involved in regulatory systems with high turnover; consistently, their function affects biological processes such as cell cycle regulation or stress response. Our findings support the functional importance of flexibility peaks, suggesting that the flexible sequence may be derived by an expansion of canonical TAYRTA polyadenylation efficiency element. The flexible (TA)n repeat amplification could be the outcome of an evolutionary neofunctionalization leading to a differential 3'-end processing and expression regulation in genes with peculiar function. Our study provides a new support to the functional role of flexibility in genomes and a strategy for its characterization inside human fragile sites.
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Affiliation(s)
- Giulia Menconi
- Dip. Informatica, Università di Pisa, Largo Pontecorvo, Pisa, Italy
- Istituto Nazionale di Alta Matematica “Francesco Severi”, Piazzale Aldo Moro, Città Universitaria, Roma, Italy
| | - Andrea Bedini
- Dept. Mathematics and Statistics, The University of Melbourne Victoria, Australia
| | - Roberto Barale
- Dip. Biologia, Università di Pisa, Via Derna, Pisa, Italy
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92
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Fungtammasan A, Ananda G, Hile SE, Su MSW, Sun C, Harris R, Medvedev P, Eckert K, Makova KD. Accurate typing of short tandem repeats from genome-wide sequencing data and its applications. Genome Res 2015; 25:736-49. [PMID: 25823460 PMCID: PMC4417121 DOI: 10.1101/gr.185892.114] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
Abstract
Short tandem repeats (STRs) are implicated in dozens of human genetic diseases and contribute significantly to genome variation and instability. Yet profiling STRs from short-read sequencing data is challenging because of their high sequencing error rates. Here, we developed STR-FM, short tandem repeat profiling using flank-based mapping, a computational pipeline that can detect the full spectrum of STR alleles from short-read data, can adapt to emerging read-mapping algorithms, and can be applied to heterogeneous genetic samples (e.g., tumors, viruses, and genomes of organelles). We used STR-FM to study STR error rates and patterns in publicly available human and in-house generated ultradeep plasmid sequencing data sets. We discovered that STRs sequenced with a PCR-free protocol have up to ninefold fewer errors than those sequenced with a PCR-containing protocol. We constructed an error correction model for genotyping STRs that can distinguish heterozygous alleles containing STRs with consecutive repeat numbers. Applying our model and pipeline to Illumina sequencing data with 100-bp reads, we could confidently genotype several disease-related long trinucleotide STRs. Utilizing this pipeline, for the first time we determined the genome-wide STR germline mutation rate from a deeply sequenced human pedigree. Additionally, we built a tool that recommends minimal sequencing depth for accurate STR genotyping, depending on repeat length and sequencing read length. The required read depth increases with STR length and is lower for a PCR-free protocol. This suite of tools addresses the pressing challenges surrounding STR genotyping, and thus is of wide interest to researchers investigating disease-related STRs and STR evolution.
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Affiliation(s)
- Arkarachai Fungtammasan
- Integrative Biosciences, Bioinformatics and Genomics Option, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Guruprasad Ananda
- Integrative Biosciences, Bioinformatics and Genomics Option, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802, USA
| | - Suzanne E Hile
- Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Marcia Shu-Wei Su
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Chen Sun
- Department of Computer Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Robert Harris
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Paul Medvedev
- Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802, USA; Department of Computer Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Kristin Eckert
- Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Department of Pathology, The Jake Gittlen Laboratories for Cancer Research, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Kateryna D Makova
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA; Center for Medical Genomics, Pennsylvania State University, University Park, Pennsylvania 16802, USA; The Genome Science Institute at the Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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93
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Williams AL, Genovese G, Dyer T, Altemose N, Truax K, Jun G, Patterson N, Myers SR, Curran JE, Duggirala R, Blangero J, Reich D, Przeworski M. Non-crossover gene conversions show strong GC bias and unexpected clustering in humans. eLife 2015; 4. [PMID: 25806687 PMCID: PMC4404656 DOI: 10.7554/elife.04637] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 03/20/2015] [Indexed: 12/15/2022] Open
Abstract
Although the past decade has seen tremendous progress in our understanding of fine-scale recombination, little is known about non-crossover (NCO) gene conversion. We report the first genome-wide study of NCO events in humans. Using SNP array data from 98 meioses, we identified 103 sites affected by NCO, of which 50/52 were confirmed in sequence data. Overlap with double strand break (DSB) hotspots indicates that most of the events are likely of meiotic origin. We estimate that a site is involved in a NCO at a rate of 5.9 × 10(-6)/bp/generation, consistent with sperm-typing studies, and infer that tract lengths span at least an order of magnitude. Observed NCO events show strong allelic bias at heterozygous AT/GC SNPs, with 68% (58-78%) transmitting GC alleles (p = 5 × 10(-4)). Strikingly, in 4 of 15 regions with resequencing data, multiple disjoint NCO tracts cluster in close proximity (∼20-30 kb), a phenomenon not previously seen in mammals.
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Affiliation(s)
- Amy L Williams
- Department of Biological Sciences, Columbia University, New York, United States
| | - Giulio Genovese
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, United States
| | - Thomas Dyer
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, United States
| | - Nicolas Altemose
- Wellcome Trust Centre for Human Genetics, Oxford University, Oxford, United Kingdom
| | - Katherine Truax
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, United States
| | - Goo Jun
- Department of Biostatistics, University of Michigan, Ann Arbor, United States
| | - Nick Patterson
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, United States
| | - Simon R Myers
- Wellcome Trust Centre for Human Genetics, Oxford University, Oxford, United Kingdom
| | - Joanne E Curran
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, United States
| | - Ravi Duggirala
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, United States
| | - John Blangero
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, United States
| | - David Reich
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, United States
| | - Molly Przeworski
- Department of Biological Sciences, Columbia University, New York, United States
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94
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Brečević L, Rinčić M, Krsnik Ž, Sedmak G, Hamid AB, Kosyakova N, Galić I, Liehr T, Borovečki F. Association of new deletion/duplication region at chromosome 1p21 with intellectual disability, severe speech deficit and autism spectrum disorder-like behavior: an all-in approach to solving the DPYD enigma. Transl Neurosci 2015; 6:59-86. [PMID: 28123791 PMCID: PMC4936614 DOI: 10.1515/tnsci-2015-0007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/29/2014] [Indexed: 12/14/2022] Open
Abstract
We describe an as yet unreported neocentric small supernumerary marker chromosome (sSMC) derived from chromosome 1p21.3p21.2. It was present in 80% of the lymphocytes in a male patient with intellectual disability, severe speech deficit, mild dysmorphic features, and hyperactivity with elements of autism spectrum disorder (ASD). Several important neurodevelopmental genes are affected by the 3.56 Mb copy number gain of 1p21.3p21.2, which may be considered reciprocal in gene content to the recently recognized 1p21.3 microdeletion syndrome. Both 1p21.3 deletions and the presented duplication display overlapping symptoms, fitting the same disorder category. Contribution of coding and non-coding genes to the phenotype is discussed in the light of cellular and intercellular homeostasis disequilibrium. In line with this the presented 1p21.3p21.2 copy number gain correlated to 1p21.3 microdeletion syndrome verifies the hypothesis of a cumulative effect of the number of deregulated genes - homeostasis disequilibrium leading to overlapping phenotypes between microdeletion and microduplication syndromes. Although miR-137 appears to be the major player in the 1p21.3p21.2 region, deregulation of the DPYD (dihydropyrimidine dehydrogenase) gene may potentially affect neighboring genes underlying the overlapping symptoms present in both the copy number loss and copy number gain of 1p21. Namely, the all-in approach revealed that DPYD is a complex gene whose expression is epigenetically regulated by long non-coding RNAs (lncRNAs) within the locus. Furthermore, the long interspersed nuclear element-1 (LINE-1) L1MC1 transposon inserted in DPYD intronic transcript 1 (DPYD-IT1) lncRNA with its parasites, TcMAR-Tigger5b and pair of Alu repeats appears to be the “weakest link” within the DPYD gene liable to break. Identification of the precise mechanism through which DPYD is epigenetically regulated, and underlying reasons why exactly the break (FRA1E) happens, will consequently pave the way toward preventing severe toxicity to the antineoplastic drug 5-fluorouracil (5-FU) and development of the causative therapy for the dihydropyrimidine dehydrogenase deficiency.
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Affiliation(s)
- Lukrecija Brečević
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
- Department for Functional Genomics, Center for Translational and Clinical Research, University of Zagreb Medical School, University Hospital Center Zagreb, Šalata 2, 10000 Zagreb, Croatia
- E-mail: ;
| | - Martina Rinčić
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
- Department for Functional Genomics, Center for Translational and Clinical Research, University of Zagreb Medical School, University Hospital Center Zagreb, Šalata 2, 10000 Zagreb, Croatia
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Željka Krsnik
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
| | - Goran Sedmak
- Croatian Institute for Brain Research, University of Zagreb Medical School, Šalata 12, 10000 Zagreb, Croatia
| | - Ahmed B. Hamid
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Nadezda Kosyakova
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Ivan Galić
- Center for Rehabilitation Stančić, Stančić bb, 10370 Stančić, Croatia
| | - Thomas Liehr
- Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, 07743 Jena, Germany
| | - Fran Borovečki
- Department for Functional Genomics, Center for Translational and Clinical Research, University of Zagreb Medical School, University Hospital Center Zagreb, Šalata 2, 10000 Zagreb, Croatia
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95
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Kim HJ, Jeon BS. Hypothesis: somatic mosaicism and Parkinson disease. Exp Neurobiol 2014; 23:271-6. [PMID: 25548528 PMCID: PMC4276799 DOI: 10.5607/en.2014.23.4.271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 09/29/2014] [Accepted: 09/29/2014] [Indexed: 12/18/2022] Open
Abstract
Mutations causing genetic disorders can occur during mitotic cell division after fertilization, which is called somatic mutations. This leads to somatic mosaicism, where two or more genetically distinct cells are present in one individual. Somatic mutations are the most well studied in cancer where it plays an important role and also have been associated with some neurodegenerative disorders. The study of somatic mosaicism in Parkinson disease (PD) is only in its infancy, and a case with somatic mutation has not yet been described. However, we can speculate that a somatic mutation affecting cells in the central nervous system including substantia nigra dopaminergic neurons could lead to the development of PD through the same pathomechanisms of genetic PD even in the absence of a germ-line mutation. Theoretically, a number of genes could be candidates for genetic analysis for the presence of somatic mosaicism. Among them, SNCA and PARK2 could be the best candidates to analyze. Because analyzing brain tissues in living patients is impossible, alternative tissues could be used to indicate the genetic status of the brain. Performance of the technology is another factor to consider when analyzing the tissues.
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Affiliation(s)
- Han-Joon Kim
- Department of Neurology and Movement Disorder Center, Parkinson Study Group, and Neuroscience Research Institute, College of Medicine, Seoul National University, Seoul, Korea
| | - Beom S Jeon
- Department of Neurology and Movement Disorder Center, Parkinson Study Group, and Neuroscience Research Institute, College of Medicine, Seoul National University, Seoul, Korea
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96
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Savelyeva L, Brueckner LM. Molecular characterization of common fragile sites as a strategy to discover cancer susceptibility genes. Cell Mol Life Sci 2014; 71:4561-75. [PMID: 25231336 PMCID: PMC11114050 DOI: 10.1007/s00018-014-1723-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [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: 12/19/2022]
Abstract
The cytogenetic hypothesis that common fragile sites (cFSs) are hotspots of cancer breakpoints is increasingly supported by recent data from whole-genome profiles of different cancers. cFSs are components of the normal chromosome structure that are particularly prone to breakage under conditions of replication stress. In recent years, cFSs have become of increasing interest in cancer research, as they not only appear to be frequent targets of genomic alterations in progressive tumors, but also already in precancerous lesions. Despite growing evidence of their importance in disease development, most cFSs have not been investigated at the molecular level and most cFS genes have not been identified. In this review, we summarize the current data on molecularly characterized cFSs, their genetic and epigenetic characteristics, and put emphasis on less-studied cFS genes as potential contributors to cancer development.
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Affiliation(s)
- Larissa Savelyeva
- Neuroblastoma Genomics, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany,
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97
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Grzeda KR, Royer-Bertrand B, Inaki K, Kim H, Hillmer AM, Liu ET, Chuang JH. Functional chromatin features are associated with structural mutations in cancer. BMC Genomics 2014; 15:1013. [PMID: 25417144 PMCID: PMC4253614 DOI: 10.1186/1471-2164-15-1013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/12/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Structural mutations (SMs) play a major role in cancer development. In some cancers, such as breast and ovarian, DNA double-strand breaks (DSBs) occur more frequently in transcribed regions, while in other cancer types such as prostate, there is a consistent depletion of breakpoints in transcribed regions. Despite such regularity, little is understood about the mechanisms driving these effects. A few works have suggested that protein binding may be relevant, e.g. in studies of androgen receptor binding and active chromatin in specific cell types. We hypothesized that this behavior might be general, i.e. that correlation between protein-DNA binding (and open chromatin) and breakpoint locations is common across divergent cancers. RESULTS We investigated this hypothesis by comprehensively analyzing the relationship among 457 ENCODE protein binding ChIP-seq experiments, 125 DnaseI and 24 FAIRE experiments, and 14,600 SMs from 8 diverse cancer datasets covering 147 samples. In most cancers, including breast and ovarian, we found enrichment of protein binding and open chromatin in the vicinity of SM breakpoints at distances up to 200 kb. Furthermore, for all cancer types we observed an enhanced enrichment in regions distant from genes when compared to regions proximal to genes, suggesting that the SM-induction mechanism is independent from the bias of DSBs to occur near transcribed regions. We also observed a stronger effect for sites with more than one protein bound. CONCLUSIONS Protein binding and open chromatin state are associated with nearby SM breakpoints in many cancer datasets. These observations suggest a consistent mechanism underlying SM locations across different cancers.
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Affiliation(s)
- Krzysztof R Grzeda
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
| | - Beryl Royer-Bertrand
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
- />Department of Medical Genetics, University of Lausanne, 1005 Lausanne, Switzerland
| | - Koichiro Inaki
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
| | - Hyunsoo Kim
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
| | - Axel M Hillmer
- />Genome Technology and Biology, Genome Institute of Singapore, Singapore, 138672 Singapore
| | - Edison T Liu
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
- />The Jackson Laboratory, Bar Harbor, ME 04609 USA
| | - Jeffrey H Chuang
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
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98
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Le Tallec B, Koundrioukoff S, Wilhelm T, Letessier A, Brison O, Debatisse M. Updating the mechanisms of common fragile site instability: how to reconcile the different views? Cell Mol Life Sci 2014; 71:4489-94. [PMID: 25248392 PMCID: PMC4232738 DOI: 10.1007/s00018-014-1720-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 08/28/2014] [Indexed: 01/26/2023]
Abstract
Common fragile sites (CFSs) are large chromosomal regions long identified by conventional cytogenetics as sequences prone to breakage in cells subjected to replication stress. The interest in CFSs came from their key role in the formation of DNA damage, resulting in chromosomal rearrangements. The instability of CFSs was notably correlated with the appearance of genome instability in precancerous lesions and during tumor progression. Identification of the molecular mechanisms responsible for their instability therefore represents a major challenge. A number of data show that breaks result from mitotic entry before replication completion but the mechanisms responsible for such delayed replication of CFSs and relaxed checkpoint surveillance are still debated. In addition, clues to the molecular events leading to breakage just start to emerge. We present here the results of recent reports addressing these questions.
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Affiliation(s)
- Benoît Le Tallec
- Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248, Paris Cedex 05, France
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99
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Kara E, Kiely AP, Proukakis C, Giffin N, Love S, Hehir J, Rantell K, Pandraud A, Hernandez DG, Nacheva E, Pittman AM, Nalls MA, Singleton AB, Revesz T, Bhatia KP, Quinn N, Hardy J, Holton JL, Houlden H. A 6.4 Mb duplication of the α-synuclein locus causing frontotemporal dementia and Parkinsonism: phenotype-genotype correlations. JAMA Neurol 2014; 71:1162-71. [PMID: 25003242 PMCID: PMC4362700 DOI: 10.1001/jamaneurol.2014.994] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
IMPORTANCE α-Synuclein (SNCA) locus duplications are associated with variable clinical features and reduced penetrance but the reasons underlying this variability are unknown. OBJECTIVES To report a novel family carrying a heterozygous 6.4 Mb duplication of the SNCA locus with an atypical clinical presentation strongly reminiscent of frontotemporal dementia and late-onset pallidopyramidal syndromes and study phenotype-genotype correlations in SNCA locus duplications. DESIGN, SETTING, AND PARTICIPANTS We report the clinical and neuropathologic features of a family carrying a 6.4 Mb duplication of the SNCA locus. To identify candidate disease modifiers, we completed a genetic analysis of the family and conducted statistical analysis on previously published cases carrying SNCA locus duplications using regression modeling with robust standard errors to account for clustering at the family level. MAIN OUTCOMES AND MEASURES We assessed whether length of the SNCA locus duplication influences disease penetrance and severity and whether extraduplication factors have a disease-modifying role. RESULTS We identified a large 6.4 Mb duplication of the SNCA locus in this family. Neuropathological analysis showed extensive α-synuclein pathology with minimal phospho-tau pathology. Genetic analysis showed an increased burden of Parkinson disease-related risk factors and the disease-predisposing H1/H1 microtubule-associated protein tau haplotype. Statistical analysis of previously published cases suggested there is a trend toward increasing disease severity and disease penetrance with increasing duplication size. The corresponding odds ratios from the univariable analyses were 1.17 (95% CI, 0.81-1.68) and 1.34 (95% CI, 0.78-2.31), respectively. Sex was significantly associated with both disease risk and severity; men compared with women had increased disease risk and severity and the corresponding odds ratios from the univariable analyses were 8.36 (95% CI, 1.97-35.42) and 5.55 (95% CI, 1.39-22.22), respectively. CONCLUSIONS AND RELEVANCE These findings further expand the phenotypic spectrum of SNCA locus duplications. Increased dosage of genes located within the duplicated region probably cannot increase disease risk and disease severity without the contribution of additional risk factors. Identification of disease modifiers accounting for the substantial phenotypic heterogeneity of patients with SNCA locus duplications could provide insight into molecular events involved in α-synuclein aggregation.
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Affiliation(s)
- Eleanna Kara
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Aoife P Kiely
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- The Queen Square Brain Bank, UCL Institute of Neurology, London, UK
| | - Christos Proukakis
- Department of Clinical Neuroscience, UCL Institute of Neurology, London, UK
| | - Nicola Giffin
- Department of Neurology, Frenchay Hospital, Bristol, UK
| | - Seth Love
- Department of Neuropathology, Frenchay Hospital, Bristol, UK
| | - Jason Hehir
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Khadija Rantell
- Biomedical Research Centre, UCL, London, UK
- Education Unit, UCL Institute of Neurology, Queen Square, London, UK
| | - Amelie Pandraud
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Dena G Hernandez
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- Laboratory of Neurogenetics, NIA, NIH, Bethesda, USA
| | | | - Alan M Pittman
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Mike A Nalls
- Laboratory of Neurogenetics, NIA, NIH, Bethesda, USA
| | | | - Tamas Revesz
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- The Queen Square Brain Bank, UCL Institute of Neurology, London, UK
| | - Kailash P Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK
| | - Niall Quinn
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK
| | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Janice L Holton
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- The Queen Square Brain Bank, UCL Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
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Du X, Servin B, Womack JE, Cao J, Yu M, Dong Y, Wang W, Zhao S. An update of the goat genome assembly using dense radiation hybrid maps allows detailed analysis of evolutionary rearrangements in Bovidae. BMC Genomics 2014; 15:625. [PMID: 25052253 PMCID: PMC4141111 DOI: 10.1186/1471-2164-15-625] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 07/10/2014] [Indexed: 01/02/2023] Open
Abstract
Background The domestic goat (Capra hircus), an important livestock species, belongs to a clade of Ruminantia, Bovidae, together with cattle, buffalo and sheep. The history of genome evolution and chromosomal rearrangements on a small scale in ruminants remain speculative. Recently completed goat genome sequence was released but is still in a draft stage. The draft sequence used a variety of assembly packages, as well as a radiation hybrid (RH) map of chromosome 1 as part of its validation. Results Using an improved RH mapping pipeline, whole-genome dense maps of 45,953 SNP markers were constructed with statistical confidence measures and the saturated maps provided a fine map resolution of approximate 65 kb. Linking RH maps to the goat sequences showed that the assemblies of scaffolds/super-scaffolds were globally accurate. However, we observed certain flaws linked to the process of anchoring chromosome using conserved synteny with cattle. Chromosome assignments, long-range order, and orientation of the scaffolds were reassessed in an updated genome sequence version. We also present new results exploiting the updated goat genome sequence to understand genomic rearrangements and chromosome evolution between mammals during species radiations. The sequence architecture of rearrangement sites between the goat and cattle genomes presented abundant segmental duplication on regions of goat chromosome 9 and 14, as well as new insertions in homologous cattle genome regions. This complex interplay between duplicated sequences and Robertsonian translocations highlights the rearrangement mechanism of centromeric nonallelic homologous recombination (NAHR) in mammals. We observed that species-specific shifts in ANKRD26 gene duplication are coincident with breakpoint reuse in divergent lineages and this gene family may play a role in chromosome stabilization in chromosome evolution. Conclusions We generated dense maps of the complete whole goat genome. The chromosomal maps allowed us to anchor and orientate assembled genome scaffolds along the chromosomes, annotate chromosome rearrangements and thereby get a better understanding of the genome evolution of ruminants and other mammals. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-625) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | - Wen Wang
- Key lab of animal genetics, breeding and reproduction of ministry education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China.
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