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Amundson KR, Ordoñez B, Santayana M, Nganga ML, Henry IM, Bonierbale M, Khan A, Tan EH, Comai L. Rare instances of haploid inducer DNA in potato dihaploids and ploidy-dependent genome instability. Plant Cell 2021; 33:2149-2163. [PMID: 33792719 PMCID: PMC8364225 DOI: 10.1093/plcell/koab100] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/26/2021] [Indexed: 05/03/2023]
Abstract
In cultivated tetraploid potato (Solanum tuberosum), reduction to diploidy (dihaploidy) allows for hybridization to diploids and introgression breeding and may facilitate the production of inbreds. Pollination with haploid inducers (HIs) yields maternal dihaploids, as well as triploid and tetraploid hybrids. Dihaploids may result from parthenogenesis, entailing the development of embryos from unfertilized eggs, or genome elimination, entailing missegregation and the loss of paternal chromosomes. A sign of genome elimination is the occasional persistence of HI DNA in some dihaploids. We characterized the genomes of 919 putative dihaploids and 134 hybrids produced by pollinating tetraploid clones with three HIs: IVP35, IVP101, and PL-4. Whole-chromosome or segmental aneuploidy was observed in 76 dihaploids, with karyotypes ranging from 2n = 2x - 1 = 23 to 2n = 2x + 3 = 27. Of the additional chromosomes in 74 aneuploids, 66 were from the non-inducer parent and 8 from the inducer parent. Overall, we detected full or partial chromosomes from the HI parent in 0.87% of the dihaploids, irrespective of parental genotypes. Chromosomal breaks commonly affected the paternal genome in the dihaploid and tetraploid progeny, but not in the triploid progeny, correlating instability to sperm ploidy and to haploid induction. The residual HI DNA discovered in the progeny is consistent with genome elimination as the mechanism of haploid induction.
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Affiliation(s)
- Kirk R. Amundson
- Plant Biology Graduate Group and Genome Center, University of California, Davis, Davis, California 95616
| | - Benny Ordoñez
- Plant Biology Graduate Group and Genome Center, University of California, Davis, Davis, California 95616
- International Potato Center (CIP), Lima 15024, Peru
- Integrative Genetics and Genomics Graduate Group, University of California, Davis, California 95616
| | | | - Mwaura Livingstone Nganga
- Plant Biology Graduate Group and Genome Center, University of California, Davis, Davis, California 95616
| | - Isabelle M. Henry
- Plant Biology Graduate Group and Genome Center, University of California, Davis, Davis, California 95616
| | - Merideth Bonierbale
- International Potato Center (CIP), Lima 15024, Peru
- Duquesa Business Centre, Malaga 29692, Spain
| | - Awais Khan
- International Potato Center (CIP), Lima 15024, Peru
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, New York 14456
| | - Ek Han Tan
- School of Biology and Ecology, University of Maine, Orono, Maine 04469
| | - Luca Comai
- Plant Biology Graduate Group and Genome Center, University of California, Davis, Davis, California 95616
- Author for correspondence:
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Banday S, Pandita RK, Mushtaq A, Bacolla A, Mir US, Singh DK, Jan S, Bhat KP, Hunt CR, Rao G, Charaka VK, Tainer JA, Pandita TK, Altaf M. Autism-Associated Vigilin Depletion Impairs DNA Damage Repair. Mol Cell Biol 2021; 41:e0008221. [PMID: 33941620 PMCID: PMC8224237 DOI: 10.1128/mcb.00082-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/17/2021] [Accepted: 04/28/2021] [Indexed: 12/24/2022] Open
Abstract
Vigilin (Vgl1) is essential for heterochromatin formation, chromosome segregation, and mRNA stability and is associated with autism spectrum disorders and cancer: vigilin, for example, can suppress proto-oncogene c-fms expression in breast cancer. Conserved from yeast to humans, vigilin is an RNA-binding protein with 14 tandemly arranged nonidentical hnRNP K-type homology (KH) domains. Here, we report that vigilin depletion increased cell sensitivity to cisplatin- or ionizing radiation (IR)-induced cell death and genomic instability due to defective DNA repair. Vigilin depletion delayed dephosphorylation of IR-induced γ-H2AX and elevated levels of residual 53BP1 and RIF1 foci, while reducing Rad51 and BRCA1 focus formation, DNA end resection, and double-strand break (DSB) repair. We show that vigilin interacts with the DNA damage response (DDR) proteins RAD51 and BRCA1, and vigilin depletion impairs their recruitment to DSB sites. Transient hydroxyurea (HU)-induced replicative stress in vigilin-depleted cells increased replication fork stalling and blocked restart of DNA synthesis. Furthermore, histone acetylation promoted vigilin recruitment to DSBs preferentially in the transcriptionally active genome. These findings uncover a novel vigilin role in DNA damage repair with implications for autism and cancer-related disorders.
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Affiliation(s)
- Shahid Banday
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Raj K. Pandita
- Houston Methodist Research Institute, Houston, Texas, USA
- Baylor College of Medicine, Houston, Texas, USA
| | - Arjamand Mushtaq
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Ulfat Syed Mir
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | | | - Sadaf Jan
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Krishna P. Bhat
- Department of Pathology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | | | - Ganesh Rao
- Baylor College of Medicine, Houston, Texas, USA
| | | | - John A. Tainer
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
- Department of Cancer Biology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas, USA
| | - Tej K. Pandita
- Houston Methodist Research Institute, Houston, Texas, USA
- Baylor College of Medicine, Houston, Texas, USA
| | - Mohammad Altaf
- Chromatin and Epigenetics Lab, Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India
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Kolářová K, Nešpor Dadejová M, Loja T, Lochmanová G, Sýkorová E, Dvořáčková M. Disruption of NAP1 genes in Arabidopsis thaliana suppresses the fas1 mutant phenotype, enhances genome stability and changes chromatin compaction. Plant J 2021; 106:56-73. [PMID: 33368779 DOI: 10.1111/tpj.15145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/21/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Histone chaperones mediate the assembly and disassembly of nucleosomes and participate in essentially all DNA-dependent cellular processes. In Arabidopsis thaliana, loss-of-function of FAS1 or FAS2 subunits of the H3-H4 histone chaperone complex CHROMATIN ASSEMBLY FACTOR 1 (CAF-1) has a dramatic effect on plant morphology, growth and overall fitness. CAF-1 dysfunction can lead to altered chromatin compaction, systematic loss of repetitive elements or increased DNA damage, clearly demonstrating its severity. How chromatin composition is maintained without functional CAF-1 remains elusive. Here we show that disruption of the H2A-H2B histone chaperone NUCLEOSOME ASSEMBLY PROTEIN 1 (NAP1) suppresses the FAS1 loss-of-function phenotype. The quadruple mutant fas1 nap1;1 nap1;2 nap1;3 shows wild-type growth, decreased sensitivity to genotoxic stress and suppression of telomere and 45S rDNA loss. Chromatin of fas1 nap1;1 nap1;2 nap1;3 plants is less accessible to micrococcal nuclease and the nuclear H3.1 and H3.3 histone pools change compared to fas1. Consistently, association between NAP1 and H3 occurs in the cytoplasm and nucleus in vivo in protoplasts. Altogether we show that NAP1 proteins play an essential role in DNA repair in fas1, which is coupled to nucleosome assembly through modulation of H3 levels in the nucleus.
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Affiliation(s)
- Karolína Kolářová
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, Brno, CZ-61137, Czech Republic
- Molecular Cytology and Cytometry, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, Brno, CZ-61265, Czech Republic
| | - Martina Nešpor Dadejová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology/Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Tomáš Loja
- Centre for Molecular Medicine, Central European Institute of Technology/Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Gabriela Lochmanová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology/Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
| | - Eva Sýkorová
- Molecular Cytology and Cytometry, Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, Brno, CZ-61265, Czech Republic
| | - Martina Dvořáčková
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology/Masaryk University, Kamenice 5, Brno, CZ-62500, Czech Republic
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Mukherjee S, Dutta A, Chakraborty A. External modulators and redox homeostasis: Scenario in radiation-induced bystander cells. Mutat Res Rev Mutat Res 2021; 787:108368. [PMID: 34083032 DOI: 10.1016/j.mrrev.2021.108368] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 12/10/2020] [Accepted: 01/16/2021] [Indexed: 01/07/2023]
Abstract
Redox homeostasis is imperative to maintain normal physiologic and metabolic functions. Radiotherapy disturbs this balance and induces genomic instability in diseased cells. However, radiation-induced effects propagate beyond the targeted cells, affecting the adjacent non-targeted cells (bystander effects). The cellular impact of radiation, thus, encompasses both targeted and non-targeted effects. Use of external modulators along with radiation can increase radio-therapeutic efficiency. The modulators' classification as protectors or sensitizers depends on interactions with damaged DNA molecules. Thus, it is necessary to realize the functions of various radio-sensitizers or radio-protectors in both irradiated and bystander cells. This review focuses on some modulators of radiation-induced bystander effects (RIBE) and their action mechanisms. Knowledge about the underlying signaling cross-talk may promote selective sensitization of radiation-targeted cells and protection of bystander cells.
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Affiliation(s)
- Sharmi Mukherjee
- Stress Biology Lab, UGC-DAE Consortium for Scientific Research, Kolkata Centre, India
| | - Anindita Dutta
- Stress Biology Lab, UGC-DAE Consortium for Scientific Research, Kolkata Centre, India
| | - Anindita Chakraborty
- Stress Biology Lab, UGC-DAE Consortium for Scientific Research, Kolkata Centre, India.
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Mognato M, Burdak-Rothkamm S, Rothkamm K. Interplay between DNA replication stress, chromatin dynamics and DNA-damage response for the maintenance of genome stability. Mutat Res Rev Mutat Res 2020; 787:108346. [PMID: 34083038 DOI: 10.1016/j.mrrev.2020.108346] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/02/2020] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
DNA replication stress is a major source of DNA damage, including double-stranded breaks that promote DNA damage response (DDR) signaling. Inefficient repair of such lesions can affect genome integrity. During DNA replication different factors act on chromatin remodeling in a coordinated way. While recent studies have highlighted individual molecular mechanisms of interaction, less is known about the orchestration of chromatin changes under replication stress. In this review we attempt to explore the complex relationship between DNA replication stress, DDR and genome integrity in mammalian cells, taking into account the role of chromatin disposition as an important modulator of DNA repair. Recent data on chromatin restoration and epigenetic re-establishment after DNA replication stress are reviewed.
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Affiliation(s)
| | - Susanne Burdak-Rothkamm
- University Medical Center Hamburg-Eppendorf, Department of Radiotherapy, Laboratory of Radiobiology & Experimental Radiation Oncology, Germany.
| | - Kai Rothkamm
- University Medical Center Hamburg-Eppendorf, Department of Radiotherapy, Laboratory of Radiobiology & Experimental Radiation Oncology, Germany.
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Mahlke MA, Nechemia-Arbely Y. Guarding the Genome: CENP-A-Chromatin in Health and Cancer. Genes (Basel) 2020; 11:genes11070810. [PMID: 32708729 PMCID: PMC7397030 DOI: 10.3390/genes11070810] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/10/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023] Open
Abstract
Faithful chromosome segregation is essential for the maintenance of genomic integrity and requires functional centromeres. Centromeres are epigenetically defined by the histone H3 variant, centromere protein A (CENP-A). Here we highlight current knowledge regarding CENP-A-containing chromatin structure, specification of centromere identity, regulation of CENP-A deposition and possible contribution to cancer formation and/or progression. CENP-A overexpression is common among many cancers and predicts poor prognosis. Overexpression of CENP-A increases rates of CENP-A deposition ectopically at sites of high histone turnover, occluding CCCTC-binding factor (CTCF) binding. Ectopic CENP-A deposition leads to mitotic defects, centromere dysfunction and chromosomal instability (CIN), a hallmark of cancer. CENP-A overexpression is often accompanied by overexpression of its chaperone Holliday Junction Recognition Protein (HJURP), leading to epigenetic addiction in which increased levels of HJURP and CENP-A become necessary to support rapidly dividing p53 deficient cancer cells. Alterations in CENP-A posttranslational modifications are also linked to chromosome segregation errors and CIN. Collectively, CENP-A is pivotal to genomic stability through centromere maintenance, perturbation of which can lead to tumorigenesis.
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Affiliation(s)
- Megan A. Mahlke
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA;
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Yael Nechemia-Arbely
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA;
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Correspondence: ; Tel.: +1-412-623-3228; Fax: +1-412-623-7828
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7
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Abstract
Haematopoiesis is governed by haematopoietic stem cells (HSCs) that produce all lineages of blood and immune cells. The maintenance of blood homeostasis requires a dynamic response of HSCs to stress, and dysregulation of these adaptive-response mechanisms underlies the development of myeloid leukaemia. Leukaemogenesis often occurs in a stepwise manner, with genetic and epigenetic changes accumulating in pre-leukaemic HSCs prior to the emergence of leukaemic stem cells (LSCs) and the development of acute myeloid leukaemia. Clinical data have revealed the existence of age-related clonal haematopoiesis, or the asymptomatic clonal expansion of mutated blood cells in the elderly, and this phenomenon is connected to susceptibility to leukaemic transformation. Here we describe how selection for specific mutations that increase HSC competitive fitness, in conjunction with additional endogenous and environmental changes, drives leukaemic transformation. We review the ways in which LSCs take advantage of normal HSC properties to promote survival and expansion, thus underlying disease recurrence and resistance to conventional therapies, and we detail our current understanding of leukaemic 'stemness' regulation. Overall, we link the cellular and molecular mechanisms regulating HSC behaviour with the functional dysregulation of these mechanisms in myeloid leukaemia and discuss opportunities for targeting LSC-specific mechanisms for the prevention or cure of malignant diseases.
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Affiliation(s)
- Masayuki Yamashita
- Columbia Stem Cell Initiative, Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA
- Division of Stem Cell and Molecular Medicine, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Paul V Dellorusso
- Columbia Stem Cell Initiative, Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Oakley C Olson
- Columbia Stem Cell Initiative, Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA
| | - Emmanuelle Passegué
- Columbia Stem Cell Initiative, Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY, USA.
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Thakar T, Leung W, Nicolae CM, Clements KE, Shen B, Bielinsky AK, Moldovan GL. Ubiquitinated-PCNA protects replication forks from DNA2-mediated degradation by regulating Okazaki fragment maturation and chromatin assembly. Nat Commun 2020; 11:2147. [PMID: 32358495 PMCID: PMC7195461 DOI: 10.1038/s41467-020-16096-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
Upon genotoxic stress, PCNA ubiquitination allows for replication of damaged DNA by recruiting lesion-bypass DNA polymerases. However, PCNA is also ubiquitinated during normal S-phase progression. By employing 293T and RPE1 cells deficient in PCNA ubiquitination, generated through CRISPR/Cas9 gene editing, here, we show that this modification promotes cellular proliferation and suppression of genomic instability under normal growth conditions. Loss of PCNA-ubiquitination results in DNA2-dependent but MRE11-independent nucleolytic degradation of nascent DNA at stalled replication forks. This degradation is linked to defective gap-filling in the wake of the replication fork and incomplete Okazaki fragment maturation, which interferes with efficient PCNA unloading by ATAD5 and subsequent nucleosome deposition by CAF-1. Moreover, concomitant loss of PCNA-ubiquitination and the BRCA pathway results in increased nascent DNA degradation and PARP inhibitor sensitivity. In conclusion, we show that by ensuring efficient Okazaki fragment maturation, PCNA-ubiquitination protects fork integrity and promotes the resistance of BRCA-deficient cells to PARP-inhibitors.
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Affiliation(s)
- Tanay Thakar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Wendy Leung
- Department of Biochemistry, Molecular Biology and Biophysics, College of Biological Sciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Claudia M Nicolae
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Kristen E Clements
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, Duarte, CA, 91010, USA
| | - Anja-Katrin Bielinsky
- Department of Biochemistry, Molecular Biology and Biophysics, College of Biological Sciences, University of Minnesota, Minneapolis, MN, 55455, USA
| | - George-Lucian Moldovan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA.
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9
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Bianchi JJ, Zhao X, Mays JC, Davoli T. Not all cancers are created equal: Tissue specificity in cancer genes and pathways. Curr Opin Cell Biol 2020; 63:135-143. [PMID: 32092639 PMCID: PMC7247947 DOI: 10.1016/j.ceb.2020.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/02/2020] [Accepted: 01/07/2020] [Indexed: 12/22/2022]
Abstract
Tumors arise through waves of genetic alterations and clonal expansion that allow tumor cells to acquire cancer hallmarks, such as genome instability and immune evasion. Recent genomic analyses showed that the vast majority of cancer driver genes are mutated in a tissue-dependent manner, that is, are altered in some cancers but not others. Often the tumor type also affects the likelihood of therapy response. What is the origin of tissue specificity in cancer? Recent studies suggest that both cell-intrinsic and cell-extrinsic factors play a role. On one hand, cell type-specific wiring of the cell signaling network determines the outcome of cancer driver gene mutations. On the other hand, the tumor cells' exposure to tissue-specific microenvironments (e.g. immune cells) also contributes to shape the tissue specificity of driver genes and of therapy response. In the future, a more complete understanding of tissue specificity in cancer may inform methods to better predict and improve therapeutic outcomes.
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Affiliation(s)
- Joy J Bianchi
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, 10016, USA
| | - Xin Zhao
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, 10016, USA
| | - Joseph C Mays
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, 10016, USA
| | - Teresa Davoli
- Institute for Systems Genetics, NYU Langone Health, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, NYU Langone Health, New York, 10016, USA.
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Abstract
Effective maintenance and stability of our genomes is essential for normal cell division, tissue homeostasis, and cellular and organismal fitness. The processes of chromosome replication and segregation require continual surveillance to insure fidelity. Accurate and efficient repair of DNA damage preserves genome integrity, which if lost can lead to multiple diseases, including cancer. Poly(ADP-ribose) a dynamic and reversible posttranslational modification and the enzymes that catalyze it (PARP1, PARP2, tankyrase 1, and tankyrase 2) function to maintain genome stability through diverse mechanisms. Here we review the role of these enzymes and the modification in genome repair, replication, and resolution in human cells.
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Affiliation(s)
- Kameron Azarm
- Department of Pathology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA
| | - Susan Smith
- Department of Pathology, Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York 10016, USA
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11
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Georgakopoulos N, Prior N, Angres B, Mastrogiovanni G, Cagan A, Harrison D, Hindley CJ, Arnes-Benito R, Liau SS, Curd A, Ivory N, Simons BD, Martincorena I, Wurst H, Saeb-Parsy K, Huch M. Long-term expansion, genomic stability and in vivo safety of adult human pancreas organoids. BMC Dev Biol 2020; 20:4. [PMID: 32098630 PMCID: PMC7043048 DOI: 10.1186/s12861-020-0209-5] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 02/03/2020] [Indexed: 01/07/2023]
Abstract
BACKGROUND Pancreatic organoid systems have recently been described for the in vitro culture of pancreatic ductal cells from mouse and human. Mouse pancreatic organoids exhibit unlimited expansion potential, while previously reported human pancreas organoid (hPO) cultures do not expand efficiently long-term in a chemically defined, serum-free medium. We sought to generate a 3D culture system for long-term expansion of human pancreas ductal cells as hPOs to serve as the basis for studies of human pancreas ductal epithelium, exocrine pancreatic diseases and the development of a genomically stable replacement cell therapy for diabetes mellitus. RESULTS Our chemically defined, serum-free, human pancreas organoid culture medium supports the generation and expansion of hPOs with high efficiency from both fresh and cryopreserved primary tissue. hPOs can be expanded from a single cell, enabling their genetic manipulation and generation of clonal cultures. hPOs expanded for months in vitro maintain their ductal morphology, biomarker expression and chromosomal integrity. Xenografts of hPOs survive long-term in vivo when transplanted into the pancreas of immunodeficient mice. Notably, mouse orthotopic transplants show no signs of tumorigenicity. Crucially, our medium also supports the establishment and expansion of hPOs in a chemically defined, modifiable and scalable, biomimetic hydrogel. CONCLUSIONS hPOs can be expanded long-term, from both fresh and cryopreserved human pancreas tissue in a chemically defined, serum-free medium with no detectable tumorigenicity. hPOs can be clonally expanded, genetically manipulated and are amenable to culture in a chemically defined hydrogel. hPOs therefore represent an abundant source of pancreas ductal cells that retain the characteristics of the tissue-of-origin, which opens up avenues for modelling diseases of the ductal epithelium and increasing understanding of human pancreas exocrine biology as well as for potentially producing insulin-secreting cells for the treatment of diabetes.
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Affiliation(s)
- Nikitas Georgakopoulos
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Cambridge Biorepository for Translational Medicine & Department of Surgery, University o.f Cambridge, and NIHR Cambridge Biomedical Research Centre, Cambridge, CB2 0QQ, UK
| | - Nicole Prior
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | | | - Gianmarco Mastrogiovanni
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Alex Cagan
- Wellcome Sanger Institute, Hinxton, Cambridgeshire, CB10 1SA, UK
| | - Daisy Harrison
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
| | - Christopher J Hindley
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Physics, The Cavendish Laboratory, University of Cambridge, Thompson Avenue, Cambridge, JJ, CB3 0HE, UK
| | - Robert Arnes-Benito
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Siong-Seng Liau
- Hepatopancreatobiliary Surgical Unit, Addenbrooke's Hospital and MRC Cancer Unit, University of Cambridge, Cambridge, CB2 0XZ, UK
| | - Abbie Curd
- Cambridge Biorepository for Translational Medicine & Department of Surgery, University o.f Cambridge, and NIHR Cambridge Biomedical Research Centre, Cambridge, CB2 0QQ, UK
| | - Natasha Ivory
- Cambridge Biorepository for Translational Medicine & Department of Surgery, University o.f Cambridge, and NIHR Cambridge Biomedical Research Centre, Cambridge, CB2 0QQ, UK
| | - Benjamin D Simons
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK
- Department of Physics, The Cavendish Laboratory, University of Cambridge, Thompson Avenue, Cambridge, JJ, CB3 0HE, UK
| | | | | | - Kourosh Saeb-Parsy
- Cambridge Biorepository for Translational Medicine & Department of Surgery, University o.f Cambridge, and NIHR Cambridge Biomedical Research Centre, Cambridge, CB2 0QQ, UK.
| | - Meritxell Huch
- The Wellcome Trust/ Cancer Research UK Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN, UK.
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany.
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Abstract
Fidelity in chromosome duplication and segregation is indispensable for maintaining genomic stability and the perpetuation of life. Challenges to genome integrity jeopardize cell survival and are at the root of different types of pathologies, such as cancer. The following three main sources of genomic instability exist: DNA damage, replicative stress, and chromosome segregation defects. In response to these challenges, eukaryotic cells have evolved control mechanisms, also known as checkpoint systems, which sense under-replicated or damaged DNA and activate specialized DNA repair machineries. Cells make use of these checkpoints throughout interphase to shield genome integrity before mitosis. Later on, when the cells enter into mitosis, the spindle assembly checkpoint (SAC) is activated and remains active until the chromosomes are properly attached to the spindle apparatus to ensure an equal segregation among daughter cells. All of these processes are tightly interconnected and under strict regulation in the context of the cell division cycle. The chromosomal instability underlying cancer pathogenesis has recently emerged as a major source for understanding the mitotic processes that helps to safeguard genome integrity. Here, we review the special interconnection between the S-phase and mitosis in the presence of under-replicated DNA regions. Furthermore, we discuss what is known about the DNA damage response activated in mitosis that preserves chromosomal integrity.
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Affiliation(s)
- Sara Ovejero
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Institute of Human Genetics, CNRS, University of Montpellier, 34000 Montpellier, France
- Department of Biological Hematology, CHU Montpellier, 34295 Montpellier, France
| | - Avelino Bueno
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
| | - María P. Sacristán
- Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, 37007 Salamanca, Spain
- Departamento de Microbiología y Genética, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain
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13
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Matos DA, Zhang JM, Ouyang J, Nguyen HD, Genois MM, Zou L. ATR Protects the Genome against R Loops through a MUS81-Triggered Feedback Loop. Mol Cell 2019; 77:514-527.e4. [PMID: 31708417 DOI: 10.1016/j.molcel.2019.10.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 08/11/2019] [Accepted: 10/08/2019] [Indexed: 12/20/2022]
Abstract
R loops arising during transcription induce genomic instability, but how cells respond to the R loop-associated genomic stress is still poorly understood. Here, we show that cells harboring high levels of R loops rely on the ATR kinase for survival. In response to aberrant R loop accumulation, the ataxia telangiectasia and Rad3-related (ATR)-Chk1 pathway is activated by R loop-induced reversed replication forks. In contrast to the activation of ATR by replication inhibitors, R loop-induced ATR activation requires the MUS81 endonuclease. ATR protects the genome from R loops by suppressing transcription-replication collisions, promoting replication fork recovery, and enforcing a G2/M cell-cycle arrest. Furthermore, ATR prevents excessive cleavage of reversed forks by MUS81, revealing a MUS81-triggered and ATR-mediated feedback loop that fine-tunes MUS81 activity at replication forks. These results suggest that ATR is a key sensor and suppressor of R loop-induced genomic instability, uncovering a signaling circuitry that safeguards the genome against R loops.
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Affiliation(s)
- Dominick A Matos
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jia-Min Zhang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Jian Ouyang
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Hai Dang Nguyen
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Marie-Michelle Genois
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA
| | - Lee Zou
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Charlestown, MA 02129, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
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14
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Dialynas G, Delabaere L, Chiolo I. Arp2/3 and Unc45 maintain heterochromatin stability in Drosophila polytene chromosomes. Exp Biol Med (Maywood) 2019; 244:1362-1371. [PMID: 31364400 PMCID: PMC6880141 DOI: 10.1177/1535370219862282] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 06/18/2019] [Indexed: 12/31/2022] Open
Abstract
Repairing DNA double-strand breaks is particularly challenging in pericentromeric heterochromatin, where the abundance of repeated sequences exacerbates the risk of ectopic recombination. In Drosophila Kc cells, accurate homologous recombination repair of heterochromatic double-strand breaks relies on the relocalization of repair sites to the nuclear periphery before Rad51 recruitment and strand invasion. This movement is driven by Arp2/3-dependent nuclear actin filaments and myosins’ ability to walk along them. Conserved mechanisms enable the relocalization of heterochromatic repair sites in mouse cells, and defects in these pathways lead to massive ectopic recombination in heterochromatin and chromosome rearrangements. In Drosophila polytene chromosomes, extensive DNA movement is blocked by a stiff structure of chromosome bundles. Repair pathways in this context are poorly characterized, and whether heterochromatic double-strand breaks relocalize in these cells is unknown. Here, we show that damage in heterochromatin results in relaxation of the heterochromatic chromocenter, consistent with a dynamic response. Arp2/3, the Arp2/3 activator Scar, and the myosin activator Unc45, are required for heterochromatin stability in polytene cells, suggesting that relocalization enables heterochromatin repair also in this tissue. Together, these studies reveal critical roles for actin polymerization and myosin motors in heterochromatin repair and genome stability across different organisms and tissue types.
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Affiliation(s)
- George Dialynas
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
| | - Laetitia Delabaere
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
| | - Irene Chiolo
- Department of Molecular and Computational Biology,
University
of Southern California, Los Angeles
90089, USA
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15
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Weeks SE, Metge BJ, Samant RS. The nucleolus: a central response hub for the stressors that drive cancer progression. Cell Mol Life Sci 2019; 76:4511-4524. [PMID: 31338556 PMCID: PMC6841648 DOI: 10.1007/s00018-019-03231-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 06/25/2019] [Accepted: 07/15/2019] [Indexed: 01/17/2023]
Abstract
The nucleolus is a sub-nuclear body known primarily for its role in ribosome biogenesis. Increased number and/or size of nucleoli have historically been used by pathologists as a prognostic indicator of cancerous lesions. This increase in nucleolar number and/or size is classically attributed to the increased need for protein synthesis in cancer cells. However, evidences suggest that the nucleolus plays critical roles in many cellular functions in both normal cell biology and disease pathologies, including cancer. As new functions of the nucleolus are elucidated, there is mounting evidence to support the role of the nucleolus in regulating additional cellular functions, particularly response to cellular stressors, maintenance of genome stability, and DNA damage repair, as well as the regulation of gene expression and biogenesis of several ribonucleoproteins. This review highlights the central role of the nucleolus in carcinogenesis and cancer progression and discusses how cancer cells may become “addicted” to nucleolar functions.
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Affiliation(s)
- Shannon E Weeks
- Department of Pathology, University of Alabama at Birmingham, WTI 320E, 1824 6th Ave South, Birmingham, AL, 35233, USA
| | - Brandon J Metge
- Department of Pathology, University of Alabama at Birmingham, WTI 320E, 1824 6th Ave South, Birmingham, AL, 35233, USA
| | - Rajeev S Samant
- Department of Pathology, University of Alabama at Birmingham, WTI 320E, 1824 6th Ave South, Birmingham, AL, 35233, USA.
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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16
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Ye CJ, Sharpe Z, Alemara S, Mackenzie S, Liu G, Abdallah B, Horne S, Regan S, Heng HH. Micronuclei and Genome Chaos: Changing the System Inheritance. Genes (Basel) 2019; 10:genes10050366. [PMID: 31086101 PMCID: PMC6562739 DOI: 10.3390/genes10050366] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/25/2019] [Accepted: 05/03/2019] [Indexed: 12/18/2022] Open
Abstract
Micronuclei research has regained its popularity due to the realization that genome chaos, a rapid and massive genome re-organization under stress, represents a major common mechanism for punctuated cancer evolution. The molecular link between micronuclei and chromothripsis (one subtype of genome chaos which has a selection advantage due to the limited local scales of chromosome re-organization), has recently become a hot topic, especially since the link between micronuclei and immune activation has been identified. Many diverse molecular mechanisms have been illustrated to explain the causative relationship between micronuclei and genome chaos. However, the newly revealed complexity also causes confusion regarding the common mechanisms of micronuclei and their impact on genomic systems. To make sense of these diverse and even conflicting observations, the genome theory is applied in order to explain a stress mediated common mechanism of the generation of micronuclei and their contribution to somatic evolution by altering the original set of information and system inheritance in which cellular selection functions. To achieve this goal, a history and a current new trend of micronuclei research is briefly reviewed, followed by a review of arising key issues essential in advancing the field, including the re-classification of micronuclei and how to unify diverse molecular characterizations. The mechanistic understanding of micronuclei and their biological function is re-examined based on the genome theory. Specifically, such analyses propose that micronuclei represent an effective way in changing the system inheritance by altering the coding of chromosomes, which belongs to the common evolutionary mechanism of cellular adaptation and its trade-off. Further studies of the role of micronuclei in disease need to be focused on the behavior of the adaptive system rather than specific molecular mechanisms that generate micronuclei. This new model can clarify issues important to stress induced micronuclei and genome instability, the formation and maintenance of genomic information, and cellular evolution essential in many common and complex diseases such as cancer.
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Affiliation(s)
- Christine J Ye
- The Division of Hematology/Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Zachary Sharpe
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Sarah Alemara
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Stephanie Mackenzie
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Guo Liu
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Batoul Abdallah
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Steve Horne
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Sarah Regan
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
| | - Henry H Heng
- Center for Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
- Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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17
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Morton EL, Forst CV, Zheng Y, DePaula-Silva AB, Ramirez NGP, Planelles V, D'Orso I. Transcriptional Circuit Fragility Influences HIV Proviral Fate. Cell Rep 2019; 27:154-171.e9. [PMID: 30943398 PMCID: PMC6461408 DOI: 10.1016/j.celrep.2019.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/14/2018] [Accepted: 02/28/2019] [Indexed: 01/12/2023] Open
Abstract
Transcriptional circuit architectures in several organisms have been evolutionarily selected to dictate precise given responses. Unlike these cellular systems, HIV is regulated through a complex circuit composed of two successive phases (host and viral), which create a positive feedback loop facilitating viral replication. However, it has long remained unclear whether both phases operate identically and to what extent the host phase influences the entire circuit. Here, we report that, although the host phase is regulated by a checkpoint whereby KAP1 mediates transcription activation, the virus evolved a minimalist system bypassing KAP1. Given the complex circuit's architecture, cell-to-cell KAP1 fluctuations impart heterogeneity in the host transcriptional responses, thus affecting the feedback loop. Mathematical modeling of a complete circuit reveals how these oscillations ultimately influence homogeneous reactivation potential of a latent virus. Thus, although HIV drives molecular innovation to fuel robust gene activation, it experiences transcriptional fragility, thereby influencing viral fate and cure efforts.
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Affiliation(s)
- Emily L Morton
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Christian V Forst
- Department of Genetics and Genomic Sciences, Icahn Institute for Data Science and Genomic Technology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yue Zheng
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ana B DePaula-Silva
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Nora-Guadalupe P Ramirez
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vicente Planelles
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Iván D'Orso
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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18
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Palazzo L, Ahel I. PARPs in genome stability and signal transduction: implications for cancer therapy. Biochem Soc Trans 2018; 46:1681-1695. [PMID: 30420415 PMCID: PMC6299239 DOI: 10.1042/bst20180418] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/15/2018] [Accepted: 09/21/2018] [Indexed: 01/03/2023]
Abstract
The poly(ADP-ribose) polymerase (PARP) superfamily of enzymes catalyses the ADP-ribosylation (ADPr) of target proteins by using nicotinamide adenine dinucleotide (NAD+) as a donor. ADPr reactions occur either in the form of attachment of a single ADP-ribose nucleotide unit on target proteins or in the form of ADP-ribose chains, with the latter called poly(ADP-ribosyl)ation. PARPs regulate many cellular processes, including the maintenance of genome stability and signal transduction. In this review, we focus on the PARP family members that possess the ability to modify proteins by poly(ADP-ribosyl)ation, namely PARP1, PARP2, Tankyrase-1, and Tankyrase-2. Here, we detail the cellular functions of PARP1 and PARP2 in the regulation of DNA damage response and describe the function of Tankyrases in Wnt-mediated signal transduction. Furthermore, we discuss how the understanding of these pathways has provided some major breakthroughs in the treatment of human cancer.
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Affiliation(s)
- Luca Palazzo
- Institute of Protein Biochemistry, National Research Council, Via Pietro Castellino 111, 80131 Naples, Italy
| | - Ivan Ahel
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, U.K.
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19
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Bétous R, Goullet de Rugy T, Pelegrini AL, Queille S, de Villartay JP, Hoffmann JS. DNA replication stress triggers rapid DNA replication fork breakage by Artemis and XPF. PLoS Genet 2018; 14:e1007541. [PMID: 30059501 PMCID: PMC6085069 DOI: 10.1371/journal.pgen.1007541] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 08/09/2018] [Accepted: 07/04/2018] [Indexed: 11/30/2022] Open
Abstract
DNA replication stress (DRS) leads to the accumulation of stalled DNA replication forks leaving a fraction of genomic loci incompletely replicated, a source of chromosomal rearrangements during their partition in mitosis. MUS81 is known to limit the occurrence of chromosomal instability by processing these unresolved loci during mitosis. Here, we unveil that the endonucleases ARTEMIS and XPF-ERCC1 can also induce stalled DNA replication forks cleavage through non-epistatic pathways all along S and G2 phases of the cell cycle. We also showed that both nucleases are recruited to chromatin to promote replication fork restart. Finally, we found that rapid chromosomal breakage controlled by ARTEMIS and XPF is important to prevent mitotic segregation defects. Collectively, these results reveal that Rapid Replication Fork Breakage (RRFB) mediated by ARTEMIS and XPF in response to DRS contributes to DNA replication efficiency and limit chromosomal instability. DNA replication is an essential process that needs to be absolutely accurate to prevent fixation of mutations which could impair cellular essential functions and promote diseases such as cancers. During S-phase DNA replication forks encounter many obstacles that block the replicative DNA polymerases and induce fork stalling. Accumulation of stalled forks or excessive fork slowing is referred to as DNA replication stress which promote a DNA damage response elicited by ATR from the stalled forks to preserve genome stability. However, how cells deal with persistently stalled replication forks is not fully understood. It has been shown that the endonuclease MUS81-EME1 can cleave the stalled forks after 24 hours of replication stress. However normal S-phase length, is commonly of about 8 hours. Thus we asked what could happen if forks stall more transiently. We uncovered that stalled DNA replication forks can break rapidly after induction of replication stress. We show that this Rapid Replication Fork Breakage (RRFB) is achieved by two endonucleases, ARTEMIS and XPF-ERCC1, which work independently of each other to resume DNA replication from the stalled forks and to prevent mitotic segregation defects. Hence, we identified new pathways preserving genome stability during replication stress.
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Affiliation(s)
- Rémy Bétous
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, Toulouse, France
- * E-mail: (RB); (JSH)
| | - Théo Goullet de Rugy
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, Toulouse, France
| | - Alessandra Luiza Pelegrini
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, Toulouse, France
- Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Sophie Queille
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, Toulouse, France
| | - Jean-Pierre de Villartay
- Laboratory “Genome Dynamics in the Immune System”, INSERM UMR1163, Université Paris Descartes Sorbonne Paris Cité, Institut Imagine, Paris, France
| | - Jean-Sébastien Hoffmann
- CRCT, Université de Toulouse, Inserm, CNRS, UPS; Equipe labellisée Ligue Contre le Cancer, Laboratoire d’excellence Toulouse Cancer, Toulouse, France
- * E-mail: (RB); (JSH)
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20
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Ono M, Lai KKY, Wu K, Nguyen C, Lin DP, Murali R, Kahn M. Nuclear receptor/Wnt beta-catenin interactions are regulated via differential CBP/p300 coactivator usage. PLoS One 2018; 13:e0200714. [PMID: 30020971 PMCID: PMC6051640 DOI: 10.1371/journal.pone.0200714] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 07/02/2018] [Indexed: 12/26/2022] Open
Abstract
Over 400 million years ago, the evolution of vertebrates gave rise to a life cycle in which the organism began to live longer particularly as an adult. To accommodate such a longer lifespan, the organism underwent adaptation, developing a mechanism for long-lived cellular homeostasis. This adaptation required a population of long-lived relatively quiescent somatic stem cells (SSCs) along with a more proliferative differentiated daughter cell population, and was necessary to safeguard the genetic attributes with which SSCs were endowed. Intriguingly, cAMP response element binding protein (CREB)-binding protein (CBP) and E1A-binding protein, 300 kDa (p300), the highly homologous Kat3 coactivators had diverged, through duplication of ancestral Kat3, immediately preceding the evolution of vertebrates, given that both CBP and p300 have been detected in nearly all vertebrates versus non-vertebrates. We now demonstrate that a relatively small, highly evolutionarily conserved, amino terminal 9 amino acid deletion in CBP versus p300, plays a critical role in allowing for both robust maintenance of genomic integrity in stem cells and the initiation of a feed-forward differentiation mechanism by tightly controlling the interaction of the nuclear receptor family with the Wnt signaling cascade in either an antagonistic or synergistic manner.
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Affiliation(s)
- Masaya Ono
- Department of Clinical Proteomics, National Cancer Center Research Institute, Tokyo, Japan
| | - Keane K. Y. Lai
- Department of Pathology, Beckman Research Institute, City of Hope, Duarte, CA, United States of America
- Department of Molecular Medicine, Beckman Research Institute, City of Hope, Duarte, CA, United States of America
- Department of Pathology and Southern California Research Center for ALPD and Cirrhosis, University of Southern California, Los Angeles, CA, United States of America
| | - Kaijin Wu
- Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA, United States of America
- Department of Biochemistry and Molecular Medicine, University of Southern California, Los Angeles, CA, United States of America
| | - Cu Nguyen
- Department of Molecular Medicine, Beckman Research Institute, City of Hope, Duarte, CA, United States of America
- Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA, United States of America
| | - David P. Lin
- Department of Pathology and Southern California Research Center for ALPD and Cirrhosis, University of Southern California, Los Angeles, CA, United States of America
| | - Ramachandran Murali
- Department of Biomedical Sciences, Research Division of Immunology, Cedars-Sinai Medical Center, Los Angeles, CA, United States of America
| | - Michael Kahn
- Department of Molecular Medicine, Beckman Research Institute, City of Hope, Duarte, CA, United States of America
- Center for Molecular Pathways and Drug Discovery, University of Southern California, Los Angeles, CA, United States of America
- Department of Biochemistry and Molecular Medicine, University of Southern California, Los Angeles, CA, United States of America
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, United States of America
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, United States of America
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21
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Rosin LF, Nguyen SC, Joyce EF. Condensin II drives large-scale folding and spatial partitioning of interphase chromosomes in Drosophila nuclei. PLoS Genet 2018; 14:e1007393. [PMID: 30001329 PMCID: PMC6042687 DOI: 10.1371/journal.pgen.1007393] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/03/2018] [Indexed: 12/26/2022] Open
Abstract
Metazoan chromosomes are folded into discrete sub-nuclear domains, referred to as chromosome territories (CTs). The molecular mechanisms that underlie the formation and maintenance of CTs during the cell cycle remain largely unknown. Here, we have developed high-resolution chromosome paints to investigate CT organization in Drosophila cycling cells. We show that large-scale chromosome folding patterns and levels of chromosome intermixing are remarkably stable across various cell types. Our data also suggest that the nucleus scales to accommodate fluctuations in chromosome size throughout the cell cycle, which limits the degree of intermixing between neighboring CTs. Finally, we show that the cohesin and condensin complexes are required for different scales of chromosome folding, with condensin II being especially important for the size, shape, and level of intermixing between CTs in interphase. These findings suggest that large-scale chromosome folding driven by condensin II influences the extent to which chromosomes interact, which may have direct consequences for cell-type specific genome stability.
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Affiliation(s)
- Leah F. Rosin
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Son C. Nguyen
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Eric F. Joyce
- Department of Genetics, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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22
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Harkness TAA. Activating the Anaphase Promoting Complex to Enhance Genomic Stability and Prolong Lifespan. Int J Mol Sci 2018; 19:ijms19071888. [PMID: 29954095 PMCID: PMC6073722 DOI: 10.3390/ijms19071888] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/19/2018] [Accepted: 06/20/2018] [Indexed: 12/19/2022] Open
Abstract
In aging cells, genomic instability is now recognized as a hallmark event. Throughout life, cells encounter multiple endogenous and exogenous DNA damaging events that are mostly repaired, but inevitably DNA mutations, chromosome rearrangements, and epigenetic deregulation begins to mount. Now that people are living longer, more and more late life time is spent suffering from age-related disease, in which genomic instability plays a critical role. However, several major questions remain heavily debated, such as the following: When does aging start? How long can we live? In order to minimize the impact of genomic instability on longevity, it is important to understand when aging starts, and to ensure repair mechanisms remain optimal from the very start to the very end. In this review, the interplay between the stress and nutrient response networks, and the regulation of homeostasis and genomic stability, is discussed. Mechanisms that link these two networks are predicted to be key lifespan determinants. The Anaphase Promoting Complex (APC), a large evolutionarily conserved ubiquitin ligase, can potentially serve this need. Recent work demonstrates that the APC maintains genomic stability, mounts a stress response, and increases longevity in yeast. Furthermore, inhibition of APC activity by glucose and nutrient response factors indicates a tight link between the APC and the stress/nutrient response networks.
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Affiliation(s)
- Troy A A Harkness
- Department of Anatomy and Cell Biology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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23
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Piazza A, Heyer WD. Multi-Invasion-Induced Rearrangements as a Pathway for Physiological and Pathological Recombination. Bioessays 2018; 40:e1700249. [PMID: 29578583 PMCID: PMC6072258 DOI: 10.1002/bies.201700249] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 02/08/2018] [Indexed: 01/24/2023]
Abstract
Cells mitigate the detrimental consequences of DNA damage on genome stability by attempting high fidelity repair. Homologous recombination templates DNA double-strand break (DSB) repair on an identical or near identical donor sequence in a process that can in principle access the entire genome. Other physiological processes, such as homolog recognition and pairing during meiosis, also harness the HR machinery using programmed DSBs to physically link homologs and generate crossovers. A consequence of the homology search process by a long nucleoprotein filament is the formation of multi-invasions (MI), a joint molecule in which the damaged ssDNA has invaded more than one donor molecule. Processing of MI joint molecules can compromise the integrity of both donor sites and lead to their rearrangement. Here, two mechanisms for the generation of rearrangements as a pathological consequence of MI processing are detailed and the potential relevance for non-allelic homologous recombination discussed. Finally, it is proposed that MI-induced crossover formation may be a feature of physiological recombination.
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Affiliation(s)
- Aurèle Piazza
- Department of Microbiology and Molecular Genetics, One Shields Avenue, University of California, Davis, CA, 95616, USA
- Spatial Regulation of Genomes, Department of Genomes and Genetics, Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - Wolf-Dietrich Heyer
- Department of Microbiology and Molecular Genetics, One Shields Avenue, University of California, Davis, CA, 95616, USA
- Department of Molecular and Cellular Biology, One Shields Avenue, University of California, Davis, CA, 95616, USA
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24
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Lindström MS, Jurada D, Bursac S, Orsolic I, Bartek J, Volarevic S. Nucleolus as an emerging hub in maintenance of genome stability and cancer pathogenesis. Oncogene 2018; 37:2351-2366. [PMID: 29429989 PMCID: PMC5931986 DOI: 10.1038/s41388-017-0121-z] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/15/2017] [Accepted: 11/15/2017] [Indexed: 12/13/2022]
Abstract
The nucleolus is the major site for synthesis of ribosomes, complex molecular machines that are responsible for protein synthesis. A wealth of research over the past 20 years has clearly indicated that both quantitative and qualitative alterations in ribosome biogenesis can drive the malignant phenotype via dysregulation of protein synthesis. However, numerous recent proteomic, genomic, and functional studies have implicated the nucleolus in the regulation of processes that are unrelated to ribosome biogenesis, including DNA-damage response, maintenance of genome stability and its spatial organization, epigenetic regulation, cell-cycle control, stress responses, senescence, global gene expression, as well as assembly or maturation of various ribonucleoprotein particles. In this review, the focus will be on features of rDNA genes, which make them highly vulnerable to DNA damage and intra- and interchromosomal recombination as well as built-in mechanisms that prevent and repair rDNA damage, and how dysregulation of this interplay affects genome-wide DNA stability, gene expression and the balance between euchromatin and heterochromatin. We will also present the most recent insights into how malfunction of these cellular processes may be a central driving force of human malignancies, and propose a promising new therapeutic approach for the treatment of cancer.
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Affiliation(s)
- Mikael S Lindström
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Deana Jurada
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia
| | - Sladana Bursac
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia
| | - Ines Orsolic
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia
| | - Jiri Bartek
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
- The Danish Cancer Society Research Centre, Copenhagen, Denmark.
| | - Sinisa Volarevic
- Department of Molecular Medicine and Biotechnology, School of Medicine, University of Rijeka, Rijeka, Croatia.
- Scientific Center of Excellence for Reproductive and Regenerative Medicine, University of Rijeka, Rijeka, Croatia.
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25
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Bennetzen JL, Wang X. Relationships between Gene Structure and Genome Instability in Flowering Plants. Mol Plant 2018; 11:407-413. [PMID: 29462722 DOI: 10.1016/j.molp.2018.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/11/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Flowering plant (angiosperm) genomes are exceptional in their variability with respect to genome size, ploidy, chromosome number, gene content, and gene arrangement. Gene movement, although observed in some of the earliest plant genome comparisons, has been relatively underinvestigated. We present herein a description of several interesting properties of plant gene and genome structure that are pertinent to the successful movement of a gene to a new location. These considerations lead us to propose a model that can explain the frequent success of plant gene mobility, namely that Small Insulated Genes Move Around (SIGMAR). The SIGMAR model is then compared with known processes for gene mobilization, and predictions of the SIGMAR model are formulated to encourage future experimentation. The overall results indicate that the frequent gene movement in angiosperm genomes is partly an outcome of the unusual properties of angiosperm genes, especially their small size and insulation from epigenetic silencing.
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Affiliation(s)
- Jeffrey L Bennetzen
- State Key Laboratory of Tea Plant Biology and Utilization/Key Laboratory of Tea Biology and Processing, Ministry of Agriculture, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China; Department of Genetics, University of Georgia, Athens, GA 30602, USA.
| | - Xuewen Wang
- State Key Laboratory of Tea Plant Biology and Utilization/Key Laboratory of Tea Biology and Processing, Ministry of Agriculture, Anhui Agricultural University, Hefei, Anhui 230036, People's Republic of China; Department of Genetics, University of Georgia, Athens, GA 30602, USA
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26
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Countryman P, Fan Y, Gorthi A, Pan H, Strickland E, Kaur P, Wang X, Lin J, Lei X, White C, You C, Wirth N, Tessmer I, Piehler J, Riehn R, Bishop AJR, Tao YJ, Wang H. Cohesin SA2 is a sequence-independent DNA-binding protein that recognizes DNA replication and repair intermediates. J Biol Chem 2018; 293:1054-1069. [PMID: 29175904 PMCID: PMC5777247 DOI: 10.1074/jbc.m117.806406] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/22/2017] [Indexed: 11/06/2022] Open
Abstract
Proper chromosome alignment and segregation during mitosis depend on cohesion between sister chromatids, mediated by the cohesin protein complex, which also plays crucial roles in diverse genome maintenance pathways. Current models attribute DNA binding by cohesin to entrapment of dsDNA by the cohesin ring subunits (SMC1, SMC3, and RAD21 in humans). However, the biophysical properties and activities of the fourth core cohesin subunit SA2 (STAG2) are largely unknown. Here, using single-molecule atomic force and fluorescence microscopy imaging as well as fluorescence anisotropy measurements, we established that SA2 binds to both dsDNA and ssDNA, albeit with a higher binding affinity for ssDNA. We observed that SA2 can switch between the 1D diffusing (search) mode on dsDNA and stable binding (recognition) mode at ssDNA gaps. Although SA2 does not specifically bind to centromeric or telomeric sequences, it does recognize DNA structures often associated with DNA replication and double-strand break repair, such as a double-stranded end, single-stranded overhang, flap, fork, and ssDNA gap. SA2 loss leads to a defect in homologous recombination-mediated DNA double-strand break repair. These results suggest that SA2 functions at intermediate DNA structures during DNA transactions in genome maintenance pathways. These findings have important implications for understanding the function of cohesin in these pathways.
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Affiliation(s)
| | - Yanlin Fan
- the Department of BioSciences, Rice University, Houston, Texas 77251
| | - Aparna Gorthi
- the Greehey Children's Cancer Research Institute and
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas 78229
| | | | | | | | | | - Jiangguo Lin
- From the Physics Department
- the Institute of Biomechanics, School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China
| | - Xiaoying Lei
- the Department of BioSciences, Rice University, Houston, Texas 77251
- the School of Public Health, Shandong University, Jinan 250012, China
| | | | - Changjiang You
- the Division of Biophysics, Universität Osnabrück, Barbarstrasse 11, 49076 Osnabrück, Germany, and
| | - Nicolas Wirth
- the Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany
| | - Ingrid Tessmer
- the Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany
| | - Jacob Piehler
- the Division of Biophysics, Universität Osnabrück, Barbarstrasse 11, 49076 Osnabrück, Germany, and
| | | | - Alexander J R Bishop
- the Greehey Children's Cancer Research Institute and
- Department of Cell Systems and Anatomy, University of Texas Health, San Antonio, Texas 78229
| | - Yizhi Jane Tao
- the Department of BioSciences, Rice University, Houston, Texas 77251
| | - Hong Wang
- From the Physics Department,
- Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695
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27
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León-Ortiz AM, Panier S, Sarek G, Vannier JB, Patel H, Campbell PJ, Boulton SJ. A Distinct Class of Genome Rearrangements Driven by Heterologous Recombination. Mol Cell 2018; 69:292-305.e6. [PMID: 29351848 PMCID: PMC5783719 DOI: 10.1016/j.molcel.2017.12.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/02/2017] [Accepted: 12/18/2017] [Indexed: 11/25/2022]
Abstract
Erroneous DNA repair by heterologous recombination (Ht-REC) is a potential threat to genome stability, but evidence supporting its prevalence is lacking. Here we demonstrate that recombination is possible between heterologous sequences and that it is a source of chromosomal alterations in mitotic and meiotic cells. Mechanistically, we find that the RTEL1 and HIM-6/BLM helicases and the BRCA1 homolog BRC-1 counteract Ht-REC in Caenorhabditis elegans, whereas mismatch repair does not. Instead, MSH-2/6 drives Ht-REC events in rtel-1 and brc-1 mutants and excessive crossovers in rtel-1 mutant meioses. Loss of vertebrate Rtel1 also causes a variety of unusually large and complex structural variations, including chromothripsis, breakage-fusion-bridge events, and tandem duplications with distant intra-chromosomal insertions, whose structure are consistent with a role for RTEL1 in preventing Ht-REC during break-induced replication. Our data establish Ht-REC as an unappreciated source of genome instability that underpins a novel class of complex genome rearrangements that likely arise during replication stress.
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Affiliation(s)
- Ana María León-Ortiz
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Stephanie Panier
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Grzegorz Sarek
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jean-Baptiste Vannier
- Telomere Replication and Stability Group, MRC London Institute of Medical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, UK
| | - Harshil Patel
- Bioinformatics and Biostatistics, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Peter J Campbell
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Simon J Boulton
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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28
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Abstract
Unrepaired DNA damage hinders the maintenance of genome integrity because it blocks the catalytic activity of replicase. The stalled replication fork can be processed through either translesion synthesis (TLS) with specific polymerases, or replication using the undamaged template. To investigate how TLS activities are regulated and how the stalled replication fork is processed in plants, reversion frequencies and homologous recombination (HR) frequencies were analyzed using GUS-based substrates. The HR frequencies in plants deficient in DNA polymerase ζ (Pol ζ) or Rev1 were higher than that in wildtype plants under normal conditions, and were significantly increased by ultraviolet light irradiation. Heat shock protein (HSP) 90 is known to be involved in various stress responses. To examine the role of HSP90 in the regulation of damage tolerance, we analyzed reversion frequencies and HR frequencies in plants grown in the presence of a HSP inhibitor, geldanamycin (GDA). Reversion frequency was lower in GDA-treated plants than in mock-treated plants. Though the HR frequency was higher in GDA-treated wildtype plants than in mock-treated plants, no significant difference was detected in Rev1-deficient plants. In yeast, TLS polymerases interacted with each other or with a replication clump component, proliferating cell nuclear antigen (PCNA). HSP90 interacted with REV1 or REV7 in Nicotiana benthamiana cells. These results suggest that HSP90 interacts with TLS polymerase(s), which promotes error-prone TLS in plants.
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Affiliation(s)
- A. N. Sakamoto
- Department of Radiation-Applied Biology Research, National Institutes for Quantum and Radiological Science and Technology (QST), Takasaki, Gumma, Japan
- CONTACT A. N. Sakamoto Department of Radiation-Applied Biology Research, National Institutes for Quantum and Radiological Science and Technology (QST), Watanuki-machi 1233, Takasaki, Gumma 370-1292, Japan
| | - H. Kaya
- Plant Molecular Biology and Virology, Graduate School of Agriculture, Ehime University, Matsuyama, Ehime, Japan
| | - M. Endo
- Plant Genome Engineering Research Unit, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
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29
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Yang Z, Hou Q, Cheng L, Xu W, Hong Y, Li S, Sun Q. RNase H1 Cooperates with DNA Gyrases to Restrict R-Loops and Maintain Genome Integrity in Arabidopsis Chloroplasts. Plant Cell 2017; 29:2478-2497. [PMID: 28939594 PMCID: PMC5774575 DOI: 10.1105/tpc.17.00305] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 09/05/2017] [Accepted: 09/20/2017] [Indexed: 05/19/2023]
Abstract
Maintaining organellar genome integrity is essential for eukaryotic cells, and many factors can threaten genome integrity. R-loops are DNA:RNA duplexes produced during transcription, with the nontemplated DNA forming a single-stranded region. R-loops function in the regulation of transcription, DNA replication, and DNA repair, but can also be susceptible to lesions that form double-stranded breaks and thus induce genome instability. From investigating the function of a plant chloroplast-localized R-loop removing enzyme AtRNH1C, we have found that it is responsible for plastid R-loop homeostasis, chloroplast genome instability, and development. Interactome analysis revealed that AtRNH1C associates with multiple chloroplast-localized DNA and RNA metabolism-related proteins, including the core DNA gyrases complex. The interaction between AtRNH1C and AtGyrases was critical for R-loop homeostasis in chloroplast and important to release the transcription-replication conflicts in the highly transcribed and replication originated cp-rDNA regions and thus to reduce the DNA damage. Our results reveal the plastid R-loop accumulation leads to chloroplast DNA instability and provide insight into the maintenance of genome integrity in chloroplasts, in which the evolutionarily conserved RNase H1 and DNA gyrase proteins are involved.
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Affiliation(s)
- Zhuo Yang
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Quancan Hou
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lingling Cheng
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xu
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yantao Hong
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shuai Li
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qianwen Sun
- Center for Plant Biology and Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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30
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Abstract
Inherited and acquired genomic abnormalities are known to cause genetic diseases and contribute to cancer formation. Recent studies demonstrated a substantial mutational load in mouse and human embryonic and induced pluripotent stem cells (ESCs and iPSCs). Single nucleotide variants, copy number variations, and larger chromosomal abnormalities may influence the differentiation capacity of pluripotent stem cells and the functionality of their derivatives in disease modeling and drug screening, and are considered a serious risk for cellular therapies based on ESC or iPSC derivatives. This review discusses the types and origins of different genetic abnormalities in pluripotent stem cells, methods for their detection, and the mechanisms of development and enrichment during reprogramming and culture expansion.
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Affiliation(s)
- Ulrich Martin
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department of Cardiothoracic, Transplantation and Vascular Surgery, REBIRTH Cluster of Excellence, German Center for Lung Research, Hannover Medical School, Germany.
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31
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Abstract
Inheritance of the DNA sequence and its proper organization into chromatin is fundamental for genome stability and function. Therefore, how specific chromatin structures are restored on newly synthesized DNA and transmitted through cell division remains a central question to understand cell fate choices and self-renewal. Propagation of genetic information and chromatin-based information in cycling cells entails genome-wide disruption and restoration of chromatin, coupled with faithful replication of DNA. In this chapter, we describe how cells duplicate the genome while maintaining its proper organization into chromatin. We reveal how specialized replication-coupled mechanisms rapidly assemble newly synthesized DNA into nucleosomes, while the complete restoration of chromatin organization including histone marks is a continuous process taking place throughout the cell cycle. Because failure to reassemble nucleosomes at replication forks blocks DNA replication progression in higher eukaryotes and leads to genomic instability, we further underline the importance of the mechanistic link between DNA replication and chromatin duplication.
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Affiliation(s)
- Constance Alabert
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Zuzana Jasencakova
- Biotech Research and Innovation Centre (BRIC), Health and Medical Faculty, University of Copenhagen, Copenhagen, Denmark
| | - Anja Groth
- Biotech Research and Innovation Centre (BRIC), Health and Medical Faculty, University of Copenhagen, Copenhagen, Denmark.
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32
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Abstract
The maintenance of genome stability is critical for proper cell function, and loss of this stability contributes to many human diseases and developmental disorders. Therefore, cells have evolved partially redundant mechanisms to monitor and protect the genome. One subcellular organelle implicated in the maintenance of genome stability is the centrosome, best known as the primary microtubule organizing center of most animal cells. Centrosomes serve many different roles throughout the cell cycle, and many of those roles, including mitotic spindle assembly, nucleation of the interphase microtubule array, DNA damage response, and efficient cell cycle progression, have been proposed to help maintain genome stability. As a result, the centrosome is itself a highly regulated entity. Here, we review evidence concerning the significance of the centrosome in promoting genome integrity. Recent advances permitting acute and persistent centrosome removal suggest we still have much to learn regarding the specific function and actual importance of centrosomes in different contexts, as well as how cells may compensate for centrosome dysfunction to maintain the integrity of the genome. Although many animal cells survive and proliferate in the absence of centrosomes, they do so aberrantly. Based on these and other studies, we conclude that centrosomes serve as critical, multifunctional organelles that promote genome stability.
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Affiliation(s)
- Dorothy A Lerit
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute; National Institutes of Health, Bethesda, MD, 20892, USA.
- National Institutes of Health, 50 South Drive, Building 50, Room 2122, Bethesda, MD, 20892, USA.
| | - John S Poulton
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27599, USA.
- University of North Carolina, Fordham 519, CB#3280, Chapel Hill, NC, 27599, USA.
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33
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Chen S, Stout JR, Dharmaiah S, Yde S, Calvi BR, Walczak CE. Transient endoreplication down-regulates the kinesin-14 HSET and contributes to genomic instability. Mol Biol Cell 2016; 27:2911-23. [PMID: 27489338 PMCID: PMC5042578 DOI: 10.1091/mbc.e16-03-0159] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 12/28/2022] Open
Abstract
Polyploid cancer cells exhibit chromosomal instability (CIN), which is associated with tumorigenesis and therapy resistance. The mechanisms that induce polyploidy and how these mechanisms contribute to CIN are not fully understood. Here we evaluate CIN in human cells that become polyploid through an experimentally induced endoreplication cycle. When these induced endoreplicating cells (iECs) returned to mitosis, it resulted in aneuploidy in daughter cells. This aneuploidy resulted from multipolar divisions, chromosome missegregation, and failure in cytokinesis. The iECs went through several rounds of division, ultimately spawning proliferative cells of reduced ploidy. iECs have reduced levels of the kinesin-14 HSET, which likely accounts for the multipolar divisions, and overexpression of HSET reduced spindle multipolarity. However, HSET overexpression had only mild effects on CIN, suggesting that additional defects must contribute to genomic instability in dividing iECs. Overall our results suggest that transient endoreplication cycles generate a diverse population of proliferative aneuploid cells that have the potential to contribute to tumor heterogeneity.
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Affiliation(s)
- Shengyao Chen
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Jane R Stout
- Medical Sciences Program, Indiana University, Bloomington, IN 47405
| | | | - Sarah Yde
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Brian R Calvi
- Department of Biology, Indiana University, Bloomington, IN 47405
| | - Claire E Walczak
- Medical Sciences Program, Indiana University, Bloomington, IN 47405
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34
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Abstract
Non-erythroid alpha spectrin (αIISp) is a structural protein which we have shown is present in the nucleus of human cells. It interacts with a number of nuclear proteins such as actin, lamin, emerin, chromatin remodeling factors, and DNA repair proteins. αIISp's interaction with DNA repair proteins has been extensively studied. We have demonstrated that nuclear αIISp is critical in DNA interstrand cross-link (ICL) repair in S phase, in both genomic (non-telomeric) and telomeric DNA, and in maintenance of genomic stability following ICL damage to DNA. We have proposed that αIISp acts as a scaffold aiding to recruit repair proteins to sites of damage. This involvement of αIISp in ICL repair and telomere maintenance after ICL damage represents new and critical functions for αIISp. These studies have led to development of a model for the role of αIISp in DNA ICL repair. They have been aided by examination of cells from patients with Fanconi anemia (FA), a repair-deficient genetic disorder in which a deficiency in αIISp leads to defective ICL repair in genomic and telomeric DNA, telomere dysfunction, and chromosome instability following DNA ICL damage. We have shown that loss of αIISp in FA cells is due to increased breakdown by the protease, µ-calpain. Importantly, we have demonstrated that this deficiency can be corrected by knockdown of µ-calpain and restoring αIISp levels to normal. This corrects a number of the phenotypic deficiencies in FA after ICL damage. These studies suggest a new and unexplored direction for therapeutically restoring genomic stability in FA cells and for correcting numerous phenotypic deficiencies occurring after ICL damage. Developing a more in-depth understanding of the importance of the interaction of αIISp with other nuclear proteins could significantly enhance our knowledge of the consequences of loss of αIISp on critical nuclear processes.
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Affiliation(s)
- Muriel W Lambert
- Department of Pathology and Laboratory Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
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35
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Wu Y, Lu J, Kang T. Human single-stranded DNA binding proteins: guardians of genome stability. Acta Biochim Biophys Sin (Shanghai) 2016; 48:671-7. [PMID: 27217471 DOI: 10.1093/abbs/gmw044] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 04/15/2016] [Indexed: 01/03/2023] Open
Abstract
Single-stranded DNA-binding proteins (SSBs) are essential for maintaining the integrity of the genome in all organisms. All processes related to DNA, such as replication, excision, repair, and recombination, require the participation of SSBs whose oligonucleotide/oligosaccharide-binding (OB)-fold domain is responsible for the interaction with single-stranded DNA (ssDNA). For a long time, the heterotrimeric replication protein A (RPA) complex was believed to be the only nuclear SSB in eukaryotes to participate in ssDNA processing, while mitochondrial SSBs that are conserved with prokaryotic SSBs were shown to be essential for maintaining genome stability in eukaryotic mitochondria. In recent years, two new proteins, hSSB1 and hSSB2 (human SSBs 1/2), were identified and have better sequence similarity to bacterial and archaeal SSBs than RPA. This review summarizes the current understanding of these human SSBs in DNA damage repair and in cell-cycle checkpoint activation following DNA damage, as well as their relationships with cancer.
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Affiliation(s)
- Yuanzhong Wu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Jinping Lu
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
| | - Tiebang Kang
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou 510060, China
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36
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Abstract
Cohesin is a multiprotein complex involved in many DNA-related processes such as proper chromosome segregation, replication, transcription, and repair. Mutations in cohesin gene pathways are responsible for human diseases, collectively referred to as cohesinopathies. In addition, both cohesin gene expression dysregulation and mutations have been identified in cancer. Cohesinopathy cells are characterized by genome instability (GIN) visualized by a constellation of markers such as chromosome aneuploidies, chromosome aberrations, precocious sister chromatid separation, premature centromere separation, micronuclei formation, and sensitivity to genotoxic drugs. The emerging picture suggests that GIN observed in cohesinopathies may result from the synergistic effects of the multiple cohesin dysfunctions. © 2016 Wiley Periodicals, Inc.
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37
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Abstract
The multistep process of cancer progresses over many years. The prevention of mutations by DNA repair pathways led to an early appreciation of a role for repair in cancer avoidance. However, the broader role of the DNA damage response (DDR) emerged more slowly. In this Timeline article, we reflect on how our understanding of the steps leading to cancer developed, focusing on the role of the DDR. We also consider how our current knowledge can be exploited for cancer therapy.
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Affiliation(s)
- Penny A Jeggo
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Laurence H Pearl
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, UK
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Weng X, Zhang H, Kan M, Ye J, Liu F, Wang T, Deng J, Tan Y, He L, Liu Y. Leukocyte telomere length is associated with advanced age-related macular degeneration in the Han Chinese population. Exp Gerontol 2015; 69:36-40. [PMID: 26049047 DOI: 10.1016/j.exger.2015.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/23/2015] [Accepted: 06/02/2015] [Indexed: 11/19/2022]
Abstract
Telomeres located at the ends of chromosomes are involved in genomic stability and play a key role in various cancers and age-related diseases. Age-related macular degeneration (AMD) is a late-onset, age-associated progressive neurodegenerative disease, which includes the geographic atrophy (GA) subtype and the choroidal neovascularization (CNV) subtype. To better understand how leukocyte telomere length (LTL) is related to AMD, we conducted an association study in 197 AMD patients and 259 healthy controls using the established quantitative PCR technique. Logistic regression was performed to evaluate the association of LTL and AMD with the age-adjusted ratio of the telomere length to the copy number of a single-copy gene (T/S). Notably, we found a significant association between AMD and LTL (OR=2.24; 95% CI=1.68-3.07; P=0.0001) after adjusting for age and sex. Furthermore, the results showed a strongly significant association between the GA subtype and the LTL (OR=4.81; 95% CI=3.15-7.82; P=0.0001) after adjusting for age and sex. Our findings provide evidence of the role that LTL plays in the pathological mechanisms of AMD, mainly in the GA subgroup but not the CNV subgroup.
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Affiliation(s)
- Xiaoling Weng
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Hong Zhang
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Mengyuan Kan
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China
| | - Junyi Ye
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Fatao Liu
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China
| | - Ting Wang
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China
| | - Jiaying Deng
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, 270 Dongan Road, Shanghai 200032, PR China
| | - Yanfang Tan
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China
| | - Lin He
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China; Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, PR China; Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200030, PR China.
| | - Yun Liu
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, PR China; Key Laboratory of Molecular Medicine, Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai 200032, PR China.
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Zhang C, Cao L, Rong L, An Z, Zhou W, Ma J, Shen WH, Zhu Y, Dong A. The chromatin-remodeling factor AtINO80 plays crucial roles in genome stability maintenance and in plant development. Plant J 2015; 82:655-68. [PMID: 25832737 DOI: 10.1111/tpj.12840] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 03/25/2015] [Accepted: 03/25/2015] [Indexed: 05/10/2023]
Abstract
INO80 is a conserved chromatin-remodeling factor in eukaryotes. While a previous study reported that the Arabidopsis thaliana INO80 (AtINO80) is required for somatic homologous recombination (HR), the role of AtINO80 in plant growth and development remains obscure. Here, we identified and characterized two independent atino80 mutant alleles, atino80-5 and atino80-6, which display similar and pleiotropic phenotypes, including smaller plant and organ size, and late flowering. Under standard growth conditions, atino80-5 showed decreased HR; however, after genotoxic treatment, HR in the mutant increased, accompanied by more DNA double-strand breaks and stronger cellular responses. Transcription analysis showed that many developmental and environmental responsive genes are overrepresented in the perturbed genes in atino80-5. These genes significantly overlapped with the category of H2A.Z body-enriched genes. AtINO80 also interacts with H2A.Z, and facilitates the enrichment of H2A.Z at the ends of the key flowering repressor genes FLC and MAF4/5. Our characterization of the atino80-5 and atino80-6 mutants confirms and extends the previous AtINO80 study, and provides perspectives for linking studies of epigenetic mechanisms involved in plant chromatin stability with plant response to developmental and environmental cues.
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Affiliation(s)
- Chi Zhang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Lin Cao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Liang Rong
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Zengxuan An
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Wangbin Zhou
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Wen-Hui Shen
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
- Institut de Biologie Moléculaire des Plantes, UPR2357 CNRS, Université de Strasbourg, 12 rue du Général Zimmer, 67084, Strasbourg Cédex, France
| | - Yan Zhu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
| | - Aiwu Dong
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 20043, China
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Gvozdev VA, Stolyarenko AD, Klenov MS. [Functions of piRNAs and the Piwi Protein in Drosophila]. Genetika 2015; 51:430-442. [PMID: 26087619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Short (25-35 nucleotides) regulatory piPHK, along with RNA-binding proteins of the Piwi family, constitute an evolutionarily conserved system that functions mainly in eukaryotic gonads. The system can be regarded as a variant of the mechanism of RNA interference, which is based on the recognition of target RNA as a result of complementary interactions with piRNA. The variants of this regulatory system function in the germline cells, including stem cells and somatic cells of the niche, ensuring maintenance of the germline stem cells and their differentiation. One of the most important functions (but not the only one) of this system is the repression of transposons, which guarantees genome stability in germline cells. This review focuses on the works of the authors of the review in the context of outstanding international achievements in a rapidly evolving re- search area, the biology of piRNA and the function of the Piwi protein.
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Pefani DE, O'Neill E. Safeguarding genome stability: RASSF1A tumor suppressor regulates BRCA2 at stalled forks. Cell Cycle 2015; 14:1624-30. [PMID: 25927241 PMCID: PMC4613848 DOI: 10.1080/15384101.2015.1035845] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 03/23/2015] [Indexed: 12/27/2022] Open
Abstract
While it has been widely established that defective fork restart after exposure to stress results in increased genomic instability, the importance of fork protection during stalling for safeguarding genomic integrity has recently been fully appreciated. BRCA2, Breast tumor suppressor, has dual functionality promoting not only DNA repair but also preventing DNA lesions at stalled forks. In response to replication stress, BRCA2 recruits RAD51 onto nascent DNA at stalled forks, protecting nascent DNA from nucleolitic cleavage. Phosphorylation of the BRCA2 C-terminal RAD51 binding site by CDK2 promotes RAD51 filament disassembly, leading to nucleolitic cleavage of newly synthesized DNA and compromised fork integrity. Recently we uncovered how the core Hippo pathway components RASSF1A, MST2 and LATS1 regulate CDK2 activity towards BRCA2, in response to fork stalling. In complex with LATS1, CDK2 exhibits reduced kinase activity which results in low levels of pBRCA2-S3291 and stable RAD51 filaments protecting nascent DNA from MRE11 cleavage. In the absence of the RASSF1A/MST2/LATS1/CDK2 pathway increased resection of newly synthesized DNA leads to chromosomal instability and malignant transformation. This function of RASSF1A in stalled replication fork protection adds to the role of RASSF1A as a tumor suppressor and builds up evidence for RASSF1A status and its prognostic and predictive value in cancer.
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Affiliation(s)
| | - Eric O'Neill
- CRUK/MRC Oxford Institute; Department of Oncology; University of Oxford; Oxford, UK
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Muchová V, Amiard S, Mozgová I, Dvořáčková M, Gallego ME, White C, Fajkus J. Homology-dependent repair is involved in 45S rDNA loss in plant CAF-1 mutants. Plant J 2015; 81:198-209. [PMID: 25359579 PMCID: PMC4309414 DOI: 10.1111/tpj.12718] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 10/23/2014] [Accepted: 10/24/2014] [Indexed: 05/19/2023]
Abstract
Arabidopsis thaliana mutants in FAS1 and FAS2 subunits of chromatin assembly factor 1 (CAF1) show progressive loss of 45S rDNA copies and telomeres. We hypothesized that homology-dependent DNA damage repair (HDR) may contribute to the loss of these repeats in fas mutants. To test this, we generated double mutants by crossing fas mutants with knock-out mutants in RAD51B, one of the Rad51 paralogs of A. thaliana. Our results show that the absence of RAD51B decreases the rate of rDNA loss, confirming the implication of RAD51B-dependent recombination in rDNA loss in the CAF1 mutants. Interestingly, this effect is not observed for telomeric repeat loss, which thus differs from that acting in rDNA loss. Involvement of DNA damage repair in rDNA dynamics in fas mutants is further supported by accumulation of double-stranded breaks (measured as γ-H2AX foci) in 45S rDNA. Occurrence of the foci is not specific for S-phase, and is ATM-independent. While the foci in fas mutants occur both in the transcribed (intranucleolar) and non-transcribed (nucleoplasmic) fraction of rDNA, double fas rad51b mutants show a specific increase in the number of the intranucleolar foci. These results suggest that the repair of double-stranded breaks present in the transcribed rDNA region is RAD51B dependent and that this contributes to rDNA repeat loss in fas mutants, presumably via the single-stranded annealing recombination pathway. Our results also highlight the importance of proper chromatin assembly in the maintenance of genome stability.
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Affiliation(s)
- Veronika Muchová
- Mendel Centre for Plant Genomics and Proteomics, CEITEC, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
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Hasselbalch HC, Thomassen M, Hasselbalch Riley C, Kjær L, Stauffer Larsen T, Jensen MK, Bjerrum OW, Kruse TA, Skov V. Whole blood transcriptional profiling reveals deregulation of oxidative and antioxidative defence genes in myelofibrosis and related neoplasms. Potential implications of downregulation of Nrf2 for genomic instability and disease progression. PLoS One 2014; 9:e112786. [PMID: 25397683 PMCID: PMC4232509 DOI: 10.1371/journal.pone.0112786] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 10/15/2014] [Indexed: 01/16/2023] Open
Abstract
The Philadelphia-negative chronic myeloproliferative neoplasms - essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF) (MPNs) - have recently been shown to be associated with chronic inflammation, oxidative stress and accumulation of reactive oxygen species (ROS). Using whole blood transcriptional profiling, we report that several oxidative stress and anti-oxidative stress genes are significantly deregulated in MPNs. Among the twenty most up- and downregulated genes, ATOX1, DEFB122, GPX8, PRDX2, PRDX6, PTGS1, and SEPP1 were progressively upregulated from ET over PV to PMF, whereas AKR1B1, CYBA, SIRT2, TTN, and UCP2 were progressively downregulated in ET, PV and PMF (all FDR <0.05). The gene Nrf2, encoding the transcription factor nuclear factor erythroid 2-related factor 2 (NFE2L2 or Nrf2) was significantly downregulated in all MPNs. Nrf2 has a key role in the regulation of the oxidative stress response and modulates both migration and retention of hematopoietic stem cells (HSCs) in their niche. The patogenetic importance of Nrf2 depletion in the context of expansion of the hematopoietic progenitor pool in MPNs is discussed with particular focus upon the implications of concomitant downregulation of Nrf2 and CXCR4 for stem cell mobilization.
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Affiliation(s)
- Hans Carl Hasselbalch
- Department of Hematology, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark
- * E-mail:
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | | | - Lasse Kjær
- Department of Hematology, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark
| | | | - Morten K. Jensen
- Department of Hematology, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark
| | - Ole Weis Bjerrum
- Department of Hematology L, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Torben A. Kruse
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Vibe Skov
- Department of Hematology, Roskilde Hospital, University of Copenhagen, Roskilde, Denmark
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Sarbajna S, Davies D, West SC. Roles of SLX1-SLX4, MUS81-EME1, and GEN1 in avoiding genome instability and mitotic catastrophe. Genes Dev 2014; 28:1124-36. [PMID: 24831703 PMCID: PMC4035540 DOI: 10.1101/gad.238303.114] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/04/2014] [Indexed: 11/24/2022]
Abstract
The resolution of recombination intermediates containing Holliday junctions (HJs) is critical for genome maintenance and proper chromosome segregation. Three pathways for HJ processing exist in human cells and involve the following enzymes/complexes: BLM-TopoIIIα-RMI1-RMI2 (BTR complex), SLX1-SLX4-MUS81-EME1 (SLX-MUS complex), and GEN1. Cycling cells preferentially use the BTR complex for the removal of double HJs in S phase, with SLX-MUS and GEN1 acting at temporally distinct phases of the cell cycle. Cells lacking SLX-MUS and GEN1 exhibit chromosome missegregation, micronucleus formation, and elevated levels of 53BP1-positive G1 nuclear bodies, suggesting that defects in chromosome segregation lead to the transmission of extensive DNA damage to daughter cells. In addition, however, we found that the effects of SLX4, MUS81, and GEN1 depletion extend beyond mitosis, since genome instability is observed throughout all phases of the cell cycle. This is exemplified in the form of impaired replication fork movement and S-phase progression, endogenous checkpoint activation, chromosome segmentation, and multinucleation. In contrast to SLX4, SLX1, the nuclease subunit of the SLX1-SLX4 structure-selective nuclease, plays no role in the replication-related phenotypes associated with SLX4/MUS81 and GEN1 depletion. These observations demonstrate that the SLX1-SLX4 nuclease and the SLX4 scaffold play divergent roles in the maintenance of genome integrity in human cells.
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Affiliation(s)
- Shriparna Sarbajna
- Clare Hall Laboratories, Cancer Research UK, London Research Institute, Herts EN6 3LD, United Kingdom
| | - Derek Davies
- London Research Institute, London WC2A 3PX, United Kingdom
| | - Stephen C. West
- Clare Hall Laboratories, Cancer Research UK, London Research Institute, Herts EN6 3LD, United Kingdom
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Aslan D. The X chromosome: does it have a role in Bloom syndrome, a genomic instability disorder? Turk J Pediatr 2014; 56:327-329. [PMID: 25341612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The Bloom syndrome, caused by mutations in a single gene [BLM (15q26.1)], is a rare genomic instability syndrome. Despite its autosomal recessive transmission, it shows a male dominance, suggesting the possibility of a subgroup with X-linked recessive inheritance. In view of the latest molecular developments achieved in the other genomic instability syndromes, the potential functions of the X chromosome in maintaining genomic stability, and particularly, the first clues of Bloom syndrome development by mechanisms other than the BLM, we suggest herein that the X chromosome should be investigated in Bloom syndrome.
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Affiliation(s)
- Deniz Aslan
- Division of Hematology, Department of Pediatrics, Gazi University Faculty of Medicine, Ankara, Turkey.
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Abstract
Histone variant H2A.Z is essential in higher eukaryotes and has different functions in the cell. Several studies indicate that H2A.Z is found at specific loci in the genome such as regulatory-gene regions, where it poises genes for transcription. Itsdeposition creates chromatin regions with particular structural characteristics which could favor rapid transcription activation. This review focuses on the highly regulated mechanism of H2A.Z deposition in chromatin which is essential for genome integrity. Chaperones escort H2A.Z to large ATP-dependent chromatin remodeling enzymes which are responsible for its deposition/eviction. Over the last ten years, biochemical, genetic and genomic studies helped us understand the precise role of these complexes in this process. It hasbeen suggested that a cooperation occurs between histone acetyltransferase and chromatin remodeling activities to incorporate H2A.Z in chromatin. Its regulated deposition near centromeres and telomeres also shows its implication in chromosomal structure integrity and parallels a role in DNA damage response. Thedynamics of H2A.Z deposition/eviction at specific loci was shown to be critical for genome expression andmaintenance, thus cell fate. Altogether, recent findings reassert the importance of the regulated depositionof this histone variant. This article is part of a Special Issue entitled: Histone chaperones and Chromatin assembly.
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Abstract
Natural transformation has significant effects on bacterial genome evolution, but the evolutionary factors maintaining this mode of bacterial sex remain uncertain. Transformation is hypothesized to have both positive and negative evolutionary effects on bacteria. It can facilitate adaptation by combining beneficial mutations into a single individual, or reduce the mutational load by exposing deleterious alleles to natural selection. Alternatively, it may expose transformed cells to damaged or otherwise mutated environmental DNA and is energetically expensive. Here, we examine the long-term effects of transformation in the naturally competent species Streptococcus pneumoniae by evolving populations of wild-type and competence-deficient strains in chemostats for 1000 generations. Half of these populations were exposed to periodic mild stress to examine context-dependent benefits of transformation. We find that competence reduces fitness gain under benign conditions; however, these costs are reduced in the presence of periodic stress. Using whole genome re-sequencing, we show that competent populations fix fewer new mutations and that competence prevents the emergence of mutators. Our results show that during evolution in benign conditions competence helps maintain genome stability but is evolutionary costly; however, during periods of stress this same conservativism enables cells to retain fitness in the face of new mutations, showing for the first time that the benefits of transformation are context dependent. Transformation of environmental DNA can provide bacteria with a means to adapt quickly to a changing environment. While this can benefit microbes by facilitating the spread of antibiotic resistance, it can also be harmful if it causes the loss of beneficial alleles from a population. Therefore, it is unclear what evolutionary factors enable transformation to persist in bacterial populations. We used the naturally transformable opportunistic pathogen Streptococcus pneumoniae to investigate the long-term benefits of transformation. We compared the fitness of laboratory populations of S. pneumoniae after 1000 generations of evolution. Half of these populations were naturally transformable (competent) while the other half was deficient for this function. At the same time, half of the evolving populations were periodically exposed to short periods of mild stress. We find that competence reduces the average fitness gain of evolving populations, but this cost is mitigated in populations facing mild stress. Using whole genome sequencing, we discovered that functional competence reduces the total number of fixed mutations and prevents hyper-mutable cells from increasing in frequency. Our results suggest that competence in S. pneumoniae is a conservative process acting to preserve alleles, rather than an innovative one that persists because it recombines beneficial mutations.
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Affiliation(s)
- Daniel J. P. Engelmoer
- Faculty of Life Science, University of Manchester, Manchester, United Kingdom
- Department of Animal Ecology, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- * E-mail: (DJPE); (DER)
| | - Ian Donaldson
- Faculty of Life Science, University of Manchester, Manchester, United Kingdom
| | - Daniel E. Rozen
- Faculty of Life Science, University of Manchester, Manchester, United Kingdom
- Institute of Biology Leiden, Leiden University, Leiden, The Netherlands
- * E-mail: (DJPE); (DER)
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48
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Miuma S, Saldivar JC, Karras JR, Waters CE, Paisie CA, Wang Y, Jin V, Sun J, Druck T, Zhang J, Huebner K. Fhit deficiency-induced global genome instability promotes mutation and clonal expansion. PLoS One 2013; 8:e80730. [PMID: 24244712 PMCID: PMC3828255 DOI: 10.1371/journal.pone.0080730] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 10/07/2013] [Indexed: 01/25/2023] Open
Abstract
Loss of Fhit expression, encoded at chromosome fragile site FRA3B, leads to increased replication stress, genome instability and accumulation of genetic alterations. We have proposed that Fhit is a genome ‘caretaker’ whose loss initiates genome instability in preneoplastic lesions. We have characterized allele copy number alterations and expression changes observed in Fhit-deficient cells in conjunction with alterations in cellular proliferation and exome mutations, using cells from mouse embryo fibroblasts (MEFs), mouse kidney, early and late after establishment in culture, and in response to carcinogen treatment. Fhit-/- MEFs escape senescence to become immortal more rapidly than Fhit+/+ MEFs; -/- MEFs and kidney cultures show allele losses and gains, while +/+ derived cells show few genomic alterations. Striking alterations in expression of p53, p21, Mcl1 and active caspase 3 occurred in mouse kidney -/- cells during progressive tissue culture passage. To define genomic changes associated with preneoplastic changes in vivo, exome DNAs were sequenced for +/+ and -/- liver tissue after treatment of mice with the carcinogen, 7,12-dimethylbenz[a]anthracene, and for +/+ and -/- kidney cells treated in vitro with this carcinogen. The -/- exome DNAs, in comparison with +/+ DNA, showed small insertions, deletions and point mutations in more genes, some likely related to preneoplastic changes. Thus, Fhit loss provides a ‘mutator’ phenotype, a cellular environment in which mild genome instability permits clonal expansion, through proliferative advantage and escape from apoptosis, in response to pressures to survive.
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Affiliation(s)
- Satoshi Miuma
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Joshua C. Saldivar
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Jenna R. Karras
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Catherine E. Waters
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Carolyn A. Paisie
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Yao Wang
- Department of Biomedical Informatics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Victor Jin
- Department of Biomedical Informatics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Jin Sun
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Teresa Druck
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Jie Zhang
- Department of Biomedical Informatics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
| | - Kay Huebner
- Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America
- * E-mail:
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Abstract
Active maintenance of genome stability is a prerequisite for the development and function of the nervous system. The high replication index during neurogenesis and the long life of mature neurons highlight the need for efficient cellular programs to safeguard genetic fidelity. Multiple DNA damage response pathways ensure that replication stress and other types of DNA lesions, such as oxidative damage, do not affect neural homeostasis. Numerous human neurologic syndromes result from defective DNA damage signaling and compromised genome integrity. These syndromes can involve different neuropathology, which highlights the diverse maintenance roles that are required for genome stability in the nervous system. Understanding how DNA damage signaling pathways promote neural development and preserve homeostasis is essential for understanding fundamental brain function.
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Affiliation(s)
- Peter J. McKinnon
- Department of Genetics, St Jude Children’s Research Hospital, Memphis TN, USA
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50
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Tilgner K, Neganova I, Moreno-Gimeno I, AL-Aama JY, Burks D, Yung S, Singhapol C, Saretzki G, Evans J, Gorbunova V, Gennery A, Przyborski S, Stojkovic M, Armstrong L, Jeggo P, Lako M. A human iPSC model of Ligase IV deficiency reveals an important role for NHEJ-mediated-DSB repair in the survival and genomic stability of induced pluripotent stem cells and emerging haematopoietic progenitors. Cell Death Differ 2013; 20:1089-100. [PMID: 23722522 PMCID: PMC3705601 DOI: 10.1038/cdd.2013.44] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 03/17/2013] [Accepted: 04/09/2013] [Indexed: 11/08/2022] Open
Abstract
DNA double strand breaks (DSBs) are the most common form of DNA damage and are repaired by non-homologous-end-joining (NHEJ) or homologous recombination (HR). Several protein components function in NHEJ, and of these, DNA Ligase IV is essential for performing the final 'end-joining' step. Mutations in DNA Ligase IV result in LIG4 syndrome, which is characterised by growth defects, microcephaly, reduced number of blood cells, increased predisposition to leukaemia and variable degrees of immunodeficiency. In this manuscript, we report the creation of a human induced pluripotent stem cell (iPSC) model of LIG4 deficiency, which accurately replicates the DSB repair phenotype of LIG4 patients. Our findings demonstrate that impairment of NHEJ-mediated-DSB repair in human iPSC results in accumulation of DSBs and enhanced apoptosis, thus providing new insights into likely mechanisms used by pluripotent stem cells to maintain their genomic integrity. Defects in NHEJ-mediated-DSB repair also led to a significant decrease in reprogramming efficiency of human cells and accumulation of chromosomal abnormalities, suggesting a key role for NHEJ in somatic cell reprogramming and providing insights for future cell based therapies for applications of LIG4-iPSCs. Although haematopoietic specification of LIG4-iPSC is not affected per se, the emerging haematopoietic progenitors show a high accumulation of DSBs and enhanced apoptosis, resulting in reduced numbers of mature haematopoietic cells. Together our findings provide new insights into the role of NHEJ-mediated-DSB repair in the survival and differentiation of progenitor cells, which likely underlies the developmental abnormalities observed in many DNA damage disorders. In addition, our findings are important for understanding how genomic instability arises in pluripotent stem cells and for defining appropriate culture conditions that restrict DNA damage and result in ex vivo expansion of stem cells with intact genomes.
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Affiliation(s)
- K Tilgner
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, UK
- NESCI, Newcastle University, Newcastle, UK
| | - I Neganova
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, UK
- NESCI, Newcastle University, Newcastle, UK
| | | | - J Y AL-Aama
- Princess Al Jawhara Al-Brahim Center of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia
| | - D Burks
- Centro de Investigacion Principe Felipe, Valencia, Spain
| | - S Yung
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, UK
- NESCI, Newcastle University, Newcastle, UK
| | - C Singhapol
- Institute for Ageing and Health, Newcastle University, Newcastle, UK
| | - G Saretzki
- Institute for Ageing and Health, Newcastle University, Newcastle, UK
| | - J Evans
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, UK
| | - V Gorbunova
- Department of Biology, University of Rochester, Rochester, NY, USA
| | - A Gennery
- Institute of Cellular Medicine, Newcastle University, Newcastle, UK
| | - S Przyborski
- School of Biological and Biomedical Sciences, Durham University, Durham, UK
| | - M Stojkovic
- Human Genetics Department, Medical Faculty, University of Kragujevac, Kragujevac, Serbia
| | - L Armstrong
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, UK
- NESCI, Newcastle University, Newcastle, UK
| | - P Jeggo
- Genome Damage and Stability Centre, University of Sussex, Brighton, UK
| | - M Lako
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, UK
- NESCI, Newcastle University, Newcastle, UK
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