1
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Mushtaq A, Mir US, Altaf M. Multifaceted functions of RNA-binding protein vigilin in gene silencing, genome stability, and autism-related disorders. J Biol Chem 2023; 299:102988. [PMID: 36758804 PMCID: PMC10011833 DOI: 10.1016/j.jbc.2023.102988] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/10/2023] Open
Abstract
RNA-binding proteins (RBPs) are emerging as important players in regulating eukaryotic gene expression and genome stability. Specific RBPs have been shown to mediate various chromatin-associated processes ranging from transcription to gene silencing and DNA repair. One of the prominent classes of RBPs is the KH domain-containing proteins. Vigilin, an evolutionarily conserved KH domain-containing RBP has been shown to be associated with diverse biological processes like RNA transport and metabolism, sterol metabolism, chromosome segregation, and carcinogenesis. We have previously reported that vigilin is essential for heterochromatin-mediated gene silencing in fission yeast. More recently, we have identified that vigilin in humans plays a critical role in efficient repair of DNA double-stranded breaks and functions in homology-directed DNA repair. In this review, we highlight the multifaceted functions of vigilin and discuss the findings in the context of gene expression, genome organization, cancer, and autism-related disorders.
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Affiliation(s)
- Arjamand Mushtaq
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Ulfat Syed Mir
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Mohammad Altaf
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India.
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2
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Wootton J, Soutoglou E. Chromatin and Nuclear Dynamics in the Maintenance of Replication Fork Integrity. Front Genet 2022; 12:773426. [PMID: 34970302 PMCID: PMC8712883 DOI: 10.3389/fgene.2021.773426] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/24/2021] [Indexed: 11/13/2022] Open
Abstract
Replication of the eukaryotic genome is a highly regulated process and stringent control is required to maintain genome integrity. In this review, we will discuss the many aspects of the chromatin and nuclear environment that play key roles in the regulation of both unperturbed and stressed replication. Firstly, the higher order organisation of the genome into A and B compartments, topologically associated domains (TADs) and sub-nuclear compartments has major implications in the control of replication timing. In addition, the local chromatin environment defined by non-canonical histone variants, histone post-translational modifications (PTMs) and enrichment of factors such as heterochromatin protein 1 (HP1) plays multiple roles in normal S phase progression and during the repair of replicative damage. Lastly, we will cover how the spatial organisation of stalled replication forks facilitates the resolution of replication stress.
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Affiliation(s)
- Jack Wootton
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Evi Soutoglou
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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3
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Kleene R, Loers G, Castillo G, Schachner M. Cell adhesion molecule L1 interacts with the chromo shadow domain of heterochromatin protein 1 isoforms α, β, and ɣ via its intracellular domain. FASEB J 2021; 36:e22074. [PMID: 34859928 DOI: 10.1096/fj.202100816r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 11/01/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Cell adhesion molecule L1 regulates multiple cell functions and L1 deficiency is linked to several neural diseases. Proteolytic processing generates functionally decisive L1 fragments, which are imported into the nucleus. By computational analysis, we found at L1's C-terminal end the chromo shadow domain-binding motif PxVxL, which directs the binding of nuclear proteins to the heterochromatin protein 1 (HP1) isoforms α, β, and ɣ. By enzyme-linked immunosorbent assay, we show that the intracellular L1 domain binds to all HP1 isoforms. These interactions involve the HP1 chromo shadow domain and are mediated via the sequence 1158 KDET1161 in the intracellular domain of murine L1, but not by L1's C-terminal PxVxL motif. Immunoprecipitation using nuclear extracts from the brain and from cultured cerebellar and cortical neurons indicates that HP1 isoforms interact with a yet unknown nuclear L1 fragment of approximately 55 kDa (L1-55), which carries ubiquitin residues. Proximity ligation indicates a close association between L1-55 and the HP1 isoforms in neuronal nuclei. This association is reduced after the treatment of neurons with inhibitors of metalloproteases, β-site of amyloid precursor protein cleaving enzyme (BACE1), or ɣ-secretase, suggesting that cleavage of full-length L1 by these proteases generates L1-55. Reduction of HP1α, -β, or -ɣ expression by siRNA decreases L1-dependent neurite outgrowth from cultured cortical neurons and decreases the L1-dependent migration of L1-transfected HEK293 cells in a scratch assay. These findings indicate that the interaction of the novel fragment L1-55 with HP1 isoforms in nuclei affects L1-dependent functions, such as neurite outgrowth and neuronal migration.
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Affiliation(s)
- Ralf Kleene
- Research Group Biosynthesis of Neural Structures, Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Gabriele Loers
- Research Group Biosynthesis of Neural Structures, Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Gaston Castillo
- Research Group Biosynthesis of Neural Structures, Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Melitta Schachner
- Department of Cell Biology and Neuroscience, Keck Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey, USA
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4
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Stanic M, Mekhail K. Integration of DNA damage responses with dynamic spatial genome organization. Trends Genet 2021; 38:290-304. [PMID: 34598804 DOI: 10.1016/j.tig.2021.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/26/2021] [Accepted: 08/31/2021] [Indexed: 11/28/2022]
Abstract
The maintenance of genome stability and cellular homeostasis depends on the temporal and spatial coordination of successive events constituting the classical DNA damage response (DDR). Recent findings suggest close integration and coordination of DDR signaling with specific cellular processes. The mechanisms underlying such coordination remain unclear. We review emerging crosstalk between DNA repair factors, chromatin remodeling, replication, transcription, spatial genome organization, cytoskeletal forces, and liquid-liquid phase separation (LLPS) in mediating DNA repair. We present an overarching DNA repair framework within which these dynamic processes intersect in nuclear space over time. Collectively, this interplay ensures the efficient assembly of DNA repair proteins onto shifting genome structures to preserve genome stability and cell survival.
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Affiliation(s)
- Mia Stanic
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, MaRS Centre, West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, University of Toronto, MaRS Centre, West Tower, 661 University Avenue, Toronto, ON M5G 1M1, Canada; Canada Research Chairs Program, Temerty Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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5
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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] [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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6
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The role of DNA damage response in amyotrophic lateral sclerosis. Essays Biochem 2021; 64:847-861. [PMID: 33078197 PMCID: PMC7588667 DOI: 10.1042/ebc20200002] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly disabling and fatal neurodegenerative disease. Due to insufficient disease-modifying treatments, there is an unmet and urgent need for elucidating disease mechanisms that occur early and represent common triggers in both familial and sporadic ALS. Emerging evidence suggests that impaired DNA damage response contributes to age-related somatic accumulation of genomic instability and can trigger or accelerate ALS pathological manifestations. In this review, we summarize and discuss recent studies indicating a direct link between DNA damage response and ALS. Further mechanistic understanding of the role genomic instability is playing in ALS disease pathophysiology will be critical for discovering new therapeutic avenues.
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7
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Li Z, Marcel N, Devkota S, Auradkar A, Hedrick SM, Gantz VM, Bier E. CopyCatchers are versatile active genetic elements that detect and quantify inter-homolog somatic gene conversion. Nat Commun 2021; 12:2625. [PMID: 33976171 PMCID: PMC8113449 DOI: 10.1038/s41467-021-22927-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/01/2021] [Indexed: 11/08/2022] Open
Abstract
CRISPR-based active genetic elements, or gene-drives, copied via homology-directed repair (HDR) in the germline, are transmitted to progeny at super-Mendelian frequencies. Active genetic elements also can generate widespread somatic mutations, but the genetic basis for such phenotypes remains uncertain. It is generally assumed that such somatic mutations are generated by non-homologous end-joining (NHEJ), the predominant double stranded break repair pathway active in somatic cells. Here, we develop CopyCatcher systems in Drosophila to detect and quantify somatic gene conversion (SGC) events. CopyCatchers inserted into two independent genetic loci reveal unexpectedly high rates of SGC in the Drosophila eye and thoracic epidermis. Focused RNAi-based genetic screens identify several unanticipated loci altering SGC efficiency, one of which (c-MYC), when downregulated, promotes SGC mediated by both plasmid and homologous chromosome-templates in human HEK293T cells. Collectively, these studies suggest that CopyCatchers can serve as effective discovery platforms to inform potential gene therapy strategies.
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Affiliation(s)
- Zhiqian Li
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Nimi Marcel
- Section of Molecular Biology, University of California San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Sushil Devkota
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Ankush Auradkar
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Stephen M Hedrick
- Section of Molecular Biology, University of California San Diego, La Jolla, CA, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Valentino M Gantz
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA
| | - Ethan Bier
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA, USA.
- Tata Institute for Genetics and Society-UCSD, La Jolla, CA, USA.
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8
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Puri D, Swamy CVB, Dhawan J, Mishra RK. Comparative nuclear matrix proteome analysis of skeletal muscle cells in different cellular states. Cell Biol Int 2021; 45:580-598. [PMID: 33200434 DOI: 10.1002/cbin.11499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 10/01/2020] [Accepted: 11/11/2020] [Indexed: 12/20/2022]
Abstract
The nuclear matrix (NuMat) serves as the structural framework for organizing and maintaining nuclear architecture, however, the mechanisms by which this non-chromatin compartment is constructed and regulated are poorly understood. This study presents a proteomic analysis of the NuMat isolated from cultured skeletal muscle cells in three distinct cellular states- proliferating myoblasts (MBs), terminally differentiated myotubes (MTs), and mitotically quiescent (G0) myoblasts. About 40% of the proteins identified were found to be common in the NuMat proteome of these morphologically and functionally distinct cell states. These proteins, termed as the "core NuMat," define the stable, conserved, structural constituent of the nucleus, with functions such as RNA splicing, cytoskeletal organization, and chromatin modification, while the remaining NuMat proteins showed cell-state specificity, consistent with a more dynamic and potentially regulatory function. Specifically, myoblast NuMat was enriched in cell cycle, DNA replication and repair proteins, myotube NuMat in muscle differentiation and muscle function proteins, while G0 NuMat was enriched in metabolic, transcription, and transport proteins. These findings offer a new perspective for a cell-state-specific role of nuclear architecture and spatial organization, integrated with diverse cellular processes, and implicate NuMat proteins in the control of the cell cycle, lineage commitment, and differentiation.
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Affiliation(s)
- Deepika Puri
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Hyderabad, India
| | - Ch V B Swamy
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Hyderabad, India
| | - Jyotsna Dhawan
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Hyderabad, India
| | - Rakesh K Mishra
- Centre for Cellular and Molecular Biology, Council for Scientific and Industrial Research, Hyderabad, India
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9
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HP1s modulate the S-Adenosyl Methionine synthesis pathway in liver cancer cells. Biochem J 2020; 477:1033-1047. [PMID: 32091571 DOI: 10.1042/bcj20190621] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 02/20/2020] [Accepted: 02/24/2020] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer in adults. Among the altered pathways leading to HCC, an increasing role is attributed to abnormal epigenetic regulation. Members of the Heterochromatin Protein (HP1) 1 family are key players in chromatin organisation, acting as docking sites for chromatin modifiers. Here, we inactivated HP1α in HepG2 human liver carcinoma cells and showed that HP1α participated in cell proliferation. HP1α-depleted cells have a global decrease in DNA methylation and consequently a perturbed chromatin organisation, as exemplified by the reactivation of transcription at centromeric and pericentromeric regions, eventhough the protein levels of chromatin writers depositing methylation marks, such as EZH2, SETDB1, SUV39H1, G9A and DNMT3A remained unaltered. This decrease was attributed mainly to a low S-Adenosyl Methionine (SAM) level, a cofactor involved in methylation processes. Furthermore, we showed that this decrease was due to a modification in the Methionine adenosyl transferase 2A RNA (MAT2A) level, which modifies the ratio of MAT1A/MAT2A, two enzymes that generate SAM. Importantly, HP1α reintroduction into HP1α-depleted cells restored the MAT2A protein to its initial level. Finally, we demonstrated that this transcriptional deregulation of MAT2A in HP1α-depleted cells relied on a lack of recruitment of HP1β and HP1γ to MAT2A promoter where an improper non-CpG methylation site was promoted in the vicinity of the transcription start site where HP1β and HP1γ bound. Altogether, these results highlight an unanticipated link between HP1 and the SAM synthesis pathway, and emphasise emerging functions of HP1s as sensors of some aspects of liver cell metabolism.
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10
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Singh PB, Belyakin SN, Laktionov PP. Biology and Physics of Heterochromatin- Like Domains/Complexes. Cells 2020; 9:E1881. [PMID: 32796726 PMCID: PMC7465696 DOI: 10.3390/cells9081881] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 11/17/2022] Open
Abstract
The hallmarks of constitutive heterochromatin, HP1 and H3K9me2/3, assemble heterochromatin-like domains/complexes outside canonical constitutively heterochromatic territories where they regulate chromatin template-dependent processes. Domains are more than 100 kb in size; complexes less than 100 kb. They are present in the genomes of organisms ranging from fission yeast to human, with an expansion in size and number in mammals. Some of the likely functions of domains/complexes include silencing of the donor mating type region in fission yeast, preservation of DNA methylation at imprinted germline differentially methylated regions (gDMRs) and regulation of the phylotypic progression during vertebrate development. Far cis- and trans-contacts between micro-phase separated domains/complexes in mammalian nuclei contribute to the emergence of epigenetic compartmental domains (ECDs) detected in Hi-C maps. A thermodynamic description of micro-phase separation of heterochromatin-like domains/complexes may require a gestalt shift away from the monomer as the "unit of incompatibility" that determines the sign and magnitude of the Flory-Huggins parameter, χ. Instead, a more dynamic structure, the oligo-nucleosomal "clutch", consisting of between 2 and 10 nucleosomes is both the long sought-after secondary structure of chromatin and its unit of incompatibility. Based on this assumption we present a simple theoretical framework that enables an estimation of χ for domains/complexes flanked by euchromatin and thereby an indication of their tendency to phase separate. The degree of phase separation is specified by χN, where N is the number of "clutches" in a domain/complex. Our approach could provide an additional tool for understanding the biophysics of the 3D genome.
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Affiliation(s)
- Prim B. Singh
- Nazarbayev University School of Medicine, Nur-Sultan City 010000, Kazakhstan
- Epigenetics Laboratory, Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
| | - Stepan N. Belyakin
- Epigenetics Laboratory, Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
- Genomics laboratory, Institute of molecular and cellular biology SD RAS, Lavrentyev ave, 8/2, 630090 Novosibirsk, Russia; (S.N.B.); (P.P.L.)
| | - Petr P. Laktionov
- Epigenetics Laboratory, Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
- Genomics laboratory, Institute of molecular and cellular biology SD RAS, Lavrentyev ave, 8/2, 630090 Novosibirsk, Russia; (S.N.B.); (P.P.L.)
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11
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Yi GZ, Huang G, Guo M, Zhang X, Wang H, Deng S, Li Y, Xiang W, Chen Z, Pan J, Li Z, Yu L, Lei B, Liu Y, Qi S. Acquired temozolomide resistance in MGMT-deficient glioblastoma cells is associated with regulation of DNA repair by DHC2. Brain 2020; 142:2352-2366. [PMID: 31347685 PMCID: PMC6658867 DOI: 10.1093/brain/awz202] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 04/05/2019] [Accepted: 04/12/2019] [Indexed: 01/05/2023] Open
Abstract
The acquisition of temozolomide resistance is a major clinical challenge for glioblastoma treatment. Chemoresistance in glioblastoma is largely attributed to repair of temozolomide-induced DNA lesions by O6-methylguanine-DNA methyltransferase (MGMT). However, some MGMT-deficient glioblastomas are still resistant to temozolomide, and the underlying molecular mechanisms remain unclear. We found that DYNC2H1 (DHC2) was expressed more in MGMT-deficient recurrent glioblastoma specimens and its expression strongly correlated to poor progression-free survival in MGMT promotor methylated glioblastoma patients. Furthermore, silencing DHC2, both in vitro and in vivo, enhanced temozolomide-induced DNA damage and significantly improved the efficiency of temozolomide treatment in MGMT-deficient glioblastoma. Using a combination of subcellular proteomics and in vitro analyses, we showed that DHC2 was involved in nuclear localization of the DNA repair proteins, namely XPC and CBX5, and knockdown of either XPC or CBX5 resulted in increased temozolomide-induced DNA damage. In summary, we identified the nuclear transportation of DNA repair proteins by DHC2 as a critical regulator of acquired temozolomide resistance in MGMT-deficient glioblastoma. Our study offers novel insights for improving therapeutic management of MGMT-deficient glioblastoma.
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Affiliation(s)
- Guo-Zhong Yi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China.,The Laboratory for Precision Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Guanglong Huang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China.,Department of Neurosurgery, Longgang Central Hospital of Shenzhen, Shenzhen 518116, Guangdong, People's Republic of China
| | - Manlan Guo
- The Laboratory for Precision Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Xi'an Zhang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Hai Wang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Shengze Deng
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Yaomin Li
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Wei Xiang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China.,Department of Neurosurgery, The First Affliated Hospital, Southwest Medical University, Luzhou 646000, Sichuan, People's Republic of China
| | - Ziyang Chen
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Jun Pan
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Zhiyong Li
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Lei Yu
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Bingxi Lei
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Yawei Liu
- The Laboratory for Precision Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China
| | - Songtao Qi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, People's Republic of China.,Nanfang Glioma Center, Guangzhou 510515, Guangdong, People's Republic of China
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12
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Kumar A, Kono H. Heterochromatin protein 1 (HP1): interactions with itself and chromatin components. Biophys Rev 2020; 12:387-400. [PMID: 32144738 PMCID: PMC7242596 DOI: 10.1007/s12551-020-00663-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/23/2020] [Indexed: 12/12/2022] Open
Abstract
Isoforms of heterochromatin protein 1 (HP1) have been known to perform a multitude of functions ranging from gene silencing, gene activation to cell cycle regulation, and cell differentiation. This functional diversity arises from the dissimilarities coded in protein sequence which confers different biophysical and biochemical properties to individual structural elements of HP1 and thereby different behavior and interaction patterns. Hence, an understanding of various interactions of the structural elements of HP1 will be of utmost importance to better elucidate chromatin dynamics in its presence. In this review, we have gathered available information about interactions of HP1 both within and with itself as well as with chromatin elements. Also, the possible implications of these interactions are discussed.
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Affiliation(s)
- Amarjeet Kumar
- Molecular Modelling and Simulation (MMS) Group, Institute for Quantum Life Science (iQLS), National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa, Kyoto, 619-0215, Japan
| | - Hidetoshi Kono
- Molecular Modelling and Simulation (MMS) Group, Institute for Quantum Life Science (iQLS), National Institutes for Quantum and Radiological Science and Technology (QST), Kizugawa, Kyoto, 619-0215, Japan.
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13
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Roach RJ, Garavís M, González C, Jameson GB, Filichev VV, Hale TK. Heterochromatin protein 1α interacts with parallel RNA and DNA G-quadruplexes. Nucleic Acids Res 2020; 48:682-693. [PMID: 31799602 PMCID: PMC6954420 DOI: 10.1093/nar/gkz1138] [Citation(s) in RCA: 207] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/19/2019] [Accepted: 11/25/2019] [Indexed: 02/06/2023] Open
Abstract
The eukaryotic genome is functionally organized into domains of transcriptionally active euchromatin and domains of highly compact transcriptionally silent heterochromatin. Heterochromatin is constitutively assembled at repetitive elements that include the telomeres and centromeres. The histone code model proposes that HP1α forms and maintains these domains of heterochromatin through the interaction of its chromodomain with trimethylated lysine 9 of histone 3, although this interaction is not the sole determinant. We show here that the unstructured hinge domain, necessary for the targeting of HP1α to constitutive heterochromatin, recognizes parallel G-quadruplex (G4) assemblies formed by the TElomeric Repeat-containing RNA (TERRA) transcribed from the telomere. This provides a mechanism by which TERRA can lead to the enrichment of HP1α at telomeres to maintain heterochromatin. Furthermore, we show that HP1α binds with a faster association rate to DNA G4s of parallel topology compared to antiparallel G4s that bind slowly or not at all. Such G4–DNAs are found in the regulatory regions of several oncogenes. This implicates specific non-canonical nucleic acid structures as determinants of HP1α function and thus RNA and DNA G4s need to be considered as contributors to chromatin domain organization and the epigenome.
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Affiliation(s)
- Ruby J Roach
- School of Fundamental Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand
| | - Miguel Garavís
- Instituto de Química Física 'Rocasolano', CSIC, Serrano 119, 28006 Madrid, Spain
| | - Carlos González
- Instituto de Química Física 'Rocasolano', CSIC, Serrano 119, 28006 Madrid, Spain
| | - Geoffrey B Jameson
- School of Fundamental Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand.,Maurice Wilkins Centre, Private Bag 92019, Auckland, New Zealand
| | - Vyacheslav V Filichev
- School of Fundamental Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand.,Maurice Wilkins Centre, Private Bag 92019, Auckland, New Zealand
| | - Tracy K Hale
- School of Fundamental Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand.,Maurice Wilkins Centre, Private Bag 92019, Auckland, New Zealand
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14
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The mouse HP1 proteins are essential for preventing liver tumorigenesis. Oncogene 2020; 39:2676-2691. [PMID: 32020053 DOI: 10.1038/s41388-020-1177-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 01/06/2020] [Accepted: 01/21/2020] [Indexed: 12/16/2022]
Abstract
Chromatin organization is essential for appropriate interpretation of the genetic information. Here, we demonstrated that the chromatin-associated proteins HP1 are dispensable for hepatocytes survival but are essential within hepatocytes to prevent liver tumor development in mice with HP1β being pivotal in these functions. Yet, we found that the loss of HP1 per se is not sufficient to induce cell transformation but renders cells more resistant to specific stress such as the expression of oncogenes and thus in fine, more prone to cell transformation. Molecular characterization of HP1-Triple KO premalignant livers and BMEL cells revealed that HP1 are essential for the maintenance of heterochromatin organization and for the regulation of specific genes with most of them having well characterized functions in liver functions and homeostasis. We further showed that some specific retrotransposons get reactivated upon loss of HP1, correlating with overexpression of genes in their neighborhood. Interestingly, we found that, although HP1-dependent genes are characterized by enrichment H3K9me3, this mark does not require HP1 for its maintenance and is not sufficient to maintain gene repression in absence of HP1. Finally, we demonstrated that the loss of TRIM28 association with HP1 recapitulated several phenotypes induced by the loss of HP1 including the reactivation of some retrotransposons and the increased incidence of liver cancer development. Altogether, our findings indicate that HP1 proteins act as guardians of liver homeostasis to prevent tumor development by modulating multiple chromatin-associated events within both the heterochromatic and euchromatic compartments, partly through regulation of the corepressor TRIM28 activity.
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15
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Das B, Jain N, Mallick B. piR‐39980 promotes cell proliferation, migration and invasion, and inhibits apoptosis via repression of SERPINB1 in human osteosarcoma. Biol Cell 2020; 112:73-91. [DOI: 10.1111/boc.201900063] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 12/14/2019] [Accepted: 12/16/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Basudeb Das
- RNAi and Functional Genomics LaboratoryDepartment of Life ScienceNational Institute of Technology Rourkela 769008 Odisha India
| | - Neha Jain
- RNAi and Functional Genomics LaboratoryDepartment of Life ScienceNational Institute of Technology Rourkela 769008 Odisha India
| | - Bibekanand Mallick
- RNAi and Functional Genomics LaboratoryDepartment of Life ScienceNational Institute of Technology Rourkela 769008 Odisha India
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16
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Zhang L, Li DQ. MORC2 regulates DNA damage response through a PARP1-dependent pathway. Nucleic Acids Res 2019; 47:8502-8520. [PMID: 31616951 PMCID: PMC6895267 DOI: 10.1093/nar/gkz545] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 06/04/2019] [Accepted: 06/10/2019] [Indexed: 01/25/2023] Open
Abstract
Microrchidia family CW-type zinc finger 2 (MORC2) is a newly identified chromatin remodeling enzyme with an emerging role in DNA damage response (DDR), but the underlying mechanism remains largely unknown. Here, we show that poly(ADP-ribose) polymerase 1 (PARP1), a key chromatin-associated enzyme responsible for the synthesis of poly(ADP-ribose) (PAR) polymers in mammalian cells, interacts with and PARylates MORC2 at two residues within its conserved CW-type zinc finger domain. Following DNA damage, PARP1 recruits MORC2 to DNA damage sites and catalyzes MORC2 PARylation, which stimulates its ATPase and chromatin remodeling activities. Mutation of PARylation residues in MORC2 results in reduced cell survival after DNA damage. MORC2, in turn, stabilizes PARP1 through enhancing acetyltransferase NAT10-mediated acetylation of PARP1 at lysine 949, which blocks its ubiquitination at the same residue and subsequent degradation by E3 ubiquitin ligase CHFR. Consequently, depletion of MORC2 or expression of an acetylation-defective PARP1 mutant impairs DNA damage-induced PAR production and PAR-dependent recruitment of DNA repair proteins to DNA lesions, leading to enhanced sensitivity to genotoxic stress. Collectively, these findings uncover a previously unrecognized mechanistic link between MORC2 and PARP1 in the regulation of cellular response to DNA damage.
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Affiliation(s)
- Lin Zhang
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Da-Qiang Li
- Shanghai Cancer Center and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Cancer Institute, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Key Laboratory of Breast Cancer in Shanghai, Shanghai Medical College, Fudan University, Shanghai 200032, China.,Key Laboratory of Medical Epigenetics and Metabolism, Shanghai Medical College, Fudan University, Shanghai 200032, China
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17
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Zimmermann MT, Williams MM, Klee EW, Lomberk GA, Urrutia R. Modeling post-translational modifications and cancer-associated mutations that impact the heterochromatin protein 1α-importin α heterodimers. Proteins 2019; 87:904-916. [PMID: 31152607 PMCID: PMC6790107 DOI: 10.1002/prot.25752] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/27/2019] [Indexed: 12/27/2022]
Abstract
Heterochromatin protein 1α (HP1α) is a protein that mediates cancer-associated processes in the cell nucleus. Proteomic experiments, reported here, demonstrate that HP1α complexes with importin α (IMPα), a protein necessary for its nuclear transport. This data is congruent with Simple Linear Motif (SLiM) analyses that identify an IMPα-binding motif within the linker that joins the two globular domains of this protein. Using molecular modeling and dynamics simulations, we develop a model of the IMPα-HP1α complex and investigate the impact of phosphorylation and genomic variants on their interaction. We demonstrate that phosphorylation of the HP1α linker likely regulates its association with IMPα, which has implications for HP1α access to the nucleus, where it functions. Cancer-associated genomic variants do not abolish the interaction of HP1α but instead lead to rearrangements where the variant proteins maintain interaction with IMPα, but with less specificity. Combined, this new mechanistic insight bears biochemical, cell biological, and biomedical relevance.
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Affiliation(s)
- Michael T. Zimmermann
- Bioinformatics Research and Development Laboratory, and Precision Medicine Simulation Unit, Genomic Science and Precision Medicine Center (GSPMC)Medical College of WisconsinMilwaukeeWisconsin
- Clinical and Translational Sciences InstituteMedical College of WisconsinMilwaukeeWisconsin
| | - Monique M. Williams
- Department of BiochemistryMayo ClinicRochesterMinnesota
- Division of Biomedical Statistics and InformaticsMayo ClinicRochesterMinnesota
| | - Eric W. Klee
- Department of BiochemistryMayo ClinicRochesterMinnesota
- Division of Biomedical Statistics and InformaticsMayo ClinicRochesterMinnesota
| | - Gwen A. Lomberk
- Division of Research, Department of SurgeryMedical College of WisconsinMilwaukeeWisconsin
- Department of Pharmacology and ToxicologyMedical College of WisconsinMilwaukeeWisconsin
- Genomic Science and Precision Medicine Center (GSPMC)Medical College of WisconsinMilwaukeeWisconsin
| | - Raul Urrutia
- Division of Research, Department of SurgeryMedical College of WisconsinMilwaukeeWisconsin
- Genomic Science and Precision Medicine Center (GSPMC)Medical College of WisconsinMilwaukeeWisconsin
- Department of BiochemistryMedical College of WisconsinMilwaukeeWisconsin
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18
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Haynes B, Gajan A, Nangia-Makker P, Shekhar MP. RAD6B is a major mediator of triple negative breast cancer cisplatin resistance: Regulation of translesion synthesis/Fanconi anemia crosstalk and BRCA1 independence. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165561. [PMID: 31639439 DOI: 10.1016/j.bbadis.2019.165561] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/26/2019] [Accepted: 09/16/2019] [Indexed: 12/20/2022]
Abstract
Triple negative breast cancer (TNBC) is an aggressive breast cancer subtype with few therapy options besides chemotherapy. Although platinum-based drugs have shown initial activity in BRCA1-mutated TNBCs, chemoresistance remains a challenge. Here we show that RAD6B (UBE2B), a principal mediator of translesion synthesis (TLS), is overexpressed in BRCA1 wild-type and mutant TNBCs, and RAD6B overexpression correlates with poor survival. Pretreatment with a RAD6-selective inhibitor, SMI#9, enhanced cisplatin chemosensitivity of BRCA1 wild-type and mutant TNBCs. SMI#9 attenuated cisplatin-induced PCNA monoubiquitination (TLS marker), FANCD2 (Fanconi anemia (FA) activation marker), and TLS polymerase POL η. SMI#9-induced decreases in γH2AX levels were associated with concomitant inhibition of H2AX monoubiquitination, suggesting a key role for RAD6 in modulating cisplatin-induced γH2AX via H2AX monoubiquitination. Concordantly, SMI#9 inhibited γH2AX, POL η and FANCD2 foci formation. RAD51 foci formation was unaffected by SMI#9, however, its recruitment to double-strand breaks was inhibited. Using the DR-GFP-based assay, we showed that RAD6B silencing or SMI#9 treatment impairs homologous recombination (HR) in HR-proficient cells. DNA fiber assays confirmed that restart of cisplatin-stalled replicating forks is inhibited by SMI#9 in both BRCA1 wild-type and mutant TNBC cells. Consistent with the in vitro data, SMI#9 and cisplatin combination treatment inhibited BRCA1 wild-type and mutant TNBC growth as compared to controls. These RAD6B activities are unaffected by BRCA1 status of TNBCs suggesting that the RAD6B function in TLS/FA crosstalk could occur in HR-dependent and independent modes. Collectively, these data implicate RAD6 as an important therapeutic target for TNBCs irrespective of their BRCA1 status.
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Affiliation(s)
- Brittany Haynes
- Karmanos Cancer Institute, 421 E. Canfield Avenue, Detroit, MI 48201, USA; Department of Oncology, Wayne State University School of Medicine, 421 E. Canfield Avenue, Detroit, MI 48201, USA
| | - Ambikai Gajan
- Karmanos Cancer Institute, 421 E. Canfield Avenue, Detroit, MI 48201, USA; Department of Oncology, Wayne State University School of Medicine, 421 E. Canfield Avenue, Detroit, MI 48201, USA
| | - Pratima Nangia-Makker
- Karmanos Cancer Institute, 421 E. Canfield Avenue, Detroit, MI 48201, USA; Department of Oncology, Wayne State University School of Medicine, 421 E. Canfield Avenue, Detroit, MI 48201, USA
| | - Malathy P Shekhar
- Karmanos Cancer Institute, 421 E. Canfield Avenue, Detroit, MI 48201, USA; Department of Oncology, Wayne State University School of Medicine, 421 E. Canfield Avenue, Detroit, MI 48201, USA; Department of Pathology, Wayne State University School of Medicine, 421 E. Canfield Avenue, Detroit, MI 48201, USA.
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19
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Barbero Barcenilla B, Shippen DE. Back to the future: The intimate and evolving connection between telomere-related factors and genotoxic stress. J Biol Chem 2019; 294:14803-14813. [PMID: 31434740 DOI: 10.1074/jbc.aw119.008145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The conversion of circular genomes to linear chromosomes during molecular evolution required the invention of telomeres. This entailed the acquisition of factors necessary to fulfill two new requirements: the need to fully replicate terminal DNA sequences and the ability to distinguish chromosome ends from damaged DNA. Here we consider the multifaceted functions of factors recruited to perpetuate and stabilize telomeres. We discuss recent theories for how telomere factors evolved from existing cellular machineries and examine their engagement in nontelomeric functions such as DNA repair, replication, and transcriptional regulation. We highlight the remarkable versatility of protection of telomeres 1 (POT1) proteins that was fueled by gene duplication and divergence events that occurred independently across several eukaryotic lineages. Finally, we consider the relationship between oxidative stress and telomeres and the enigmatic role of telomere-associated proteins in mitochondria. These findings point to an evolving and intimate connection between telomeres and cellular physiology and the strong drive to maintain chromosome integrity.
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Affiliation(s)
- Borja Barbero Barcenilla
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
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20
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Williams MM, Mathison AJ, Christensen T, Greipp PT, Knutson DL, Klee EW, Zimmermann MT, Iovanna J, Lomberk GA, Urrutia RA. Aurora kinase B-phosphorylated HP1α functions in chromosomal instability. Cell Cycle 2019; 18:1407-1421. [PMID: 31130069 PMCID: PMC6592258 DOI: 10.1080/15384101.2019.1618126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/17/2019] [Accepted: 05/08/2019] [Indexed: 01/25/2023] Open
Abstract
Heterochromatin Protein 1 α (HP1α) associates with members of the chromosome passenger complex (CPC) during mitosis, at centromeres where it is required for full Aurora Kinase B (AURKB) activity. Conversely, recent reports have identified AURKB as the major kinase responsible for phosphorylation of HP1α at Serine 92 (S92) during mitosis. Thus, the current study was designed to better understand the functional role of this posttranslationally modified form of HP1α. We find that S92-phosphorylated HP1α is generated in cells at early prophase, localizes to centromeres, and associates with regulators of chromosome stability, such as Inner Centromere Protein, INCENP. In mouse embryonic fibroblasts, HP1α knockout alone or reconstituted with a non-phosphorylatable (S92A) HP1α mutant results in mitotic chromosomal instability characterized by the formation of anaphase/telophase chromatin bridges and micronuclei. These effects are rescued by exogenous expression of wild type HP1α or a phosphomimetic (S92D) variant. Thus, the results from the current study extend our knowledge of the role of HP1α in chromosomal stability during mitosis.
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Affiliation(s)
- Monique M. Williams
- Departments of Biochemistry and Biostatistics, Mayo Clinic, Rochester, MN, USA
| | - Angela J. Mathison
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, WI, USA
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Trent Christensen
- Departments of Biochemistry and Biostatistics, Mayo Clinic, Rochester, MN, USA
| | - Patricia T. Greipp
- Medical Genome Facility, Cytogenetics Core Laboratory, Rochester, MN, USA
| | - Darlene L. Knutson
- Medical Genome Facility, Cytogenetics Core Laboratory, Rochester, MN, USA
| | - Eric W. Klee
- Departments of Biochemistry and Biostatistics, Mayo Clinic, Rochester, MN, USA
| | - Michael T. Zimmermann
- Bioinformatics Research and Development Laboratory, Genomics Sciences and Precision Medicine Center, Medical College of Wisconsin, Milwaukee, WI, USA
- Clinical and Translational Sciences Institute, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Juan Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Aix-Marseille Université and Institut Paoli-Calmettes, Parc Scientifique et Technologique de Luminy, Marseille, France
| | - Gwen A. Lomberk
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, WI, USA
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Raul A. Urrutia
- Genomics and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, WI, USA
- Division of Research, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA
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21
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Afzal S, Garg S, Ishida Y, Terao K, Kaul SC, Wadhwa R. Rat Glioma Cell-Based Functional Characterization of Anti-Stress and Protein Deaggregation Activities in the Marine Carotenoids, Astaxanthin and Fucoxanthin. Mar Drugs 2019; 17:E189. [PMID: 30909572 PMCID: PMC6470788 DOI: 10.3390/md17030189] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 03/13/2019] [Accepted: 03/20/2019] [Indexed: 12/12/2022] Open
Abstract
Stress, protein aggregation, and loss of functional properties of cells have been shown to contribute to several deleterious pathologies including cancer and neurodegeneration. The incidence of these pathologies has also been shown to increase with age and are often presented as evidence to the cumulative effect of stress and protein aggregation. Prevention or delay of onset of these diseases may prove to be unprecedentedly beneficial. In this study, we explored the anti-stress and differentiation-inducing potential of two marine bioactive carotenoids (astaxanthin and fucoxanthin) using rat glioma cells as a model. We found that the low (nontoxic) doses of both protected cells against UV-induced DNA damage, heavy metal, and heat-induced protein misfolding and aggregation of proteins. Their long-term treatment in glioma cells caused the induction of physiological differentiation into astrocytes. These phenotypes were supported by upregulation of proteins that regulate cell proliferation, DNA damage repair mechanism, and glial differentiation, suggesting their potential for prevention and treatment of stress, protein aggregation, and age-related pathologies.
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Affiliation(s)
- Sajal Afzal
- DAILAB, DBT-AIST International Center for Translational & Environmental Research (DAICENTER), National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba 305-8565, Japan.
- School of Integrative and Global Majors, University of Tsukuba, Tsukuba 305-8577, Japan.
| | - Sukant Garg
- DAILAB, DBT-AIST International Center for Translational & Environmental Research (DAICENTER), National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba 305-8565, Japan.
| | - Yoshiyuki Ishida
- CycloChem Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
| | - Keiji Terao
- CycloChem Co., Ltd., 7-4-5 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
| | - Sunil C Kaul
- DAILAB, DBT-AIST International Center for Translational & Environmental Research (DAICENTER), National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba 305-8565, Japan.
| | - Renu Wadhwa
- DAILAB, DBT-AIST International Center for Translational & Environmental Research (DAICENTER), National Institute of Advanced Industrial Science & Technology (AIST), Tsukuba 305-8565, Japan.
- School of Integrative and Global Majors, University of Tsukuba, Tsukuba 305-8577, Japan.
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22
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Abstract
The existence of exoplanets orbiting low mass-stars is one of the most significant discoveries of our time. Especially intriguing to us is the possibility that Earth-sized exoplanets within a habitable zone might harbor life-forms that resemble our own RNA/DNA-based species. We further narrow this theoretical possibility with the following question: if alien life does indeed exist elsewhere, would extraterrestrial life be burdened with earthly diseases? Given that the chemistry of the universe is subject to specific rules, restraints, and predictable outcomes, we argue that cancer-signaling pathways might be programmed into the life cycle of habitable exoplanets. This hypothetical prediction is also based on evolutionary convergence, the repeated emergence of biological similarity that occurs when disparate life-forms adapt to comparable selection pressures. The possibility that mutations and nucleotide base rearrangements that drive cancer growth might be fixed in the chemical hardware of alien life provides us with the opportunity to wonder and consider the origins, evolution, and ubiquity of disease beyond Earth.
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Affiliation(s)
| | | | - Joerg R Leheste
- Epidemiology and Public Health, Minnesota College of Osteopathic Medicine, Gaylord, USA
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23
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γH2AX prefers late replicating metaphase chromosome regions. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2018; 836:114-121. [PMID: 30442336 DOI: 10.1016/j.mrgentox.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 04/20/2018] [Accepted: 06/01/2018] [Indexed: 11/23/2022]
Abstract
DNA damage response (DDR) constitutes a protein pathway to handle eukaryotic DNA lesions in the context of chromatin. DDR engages the recruitment of signaling, transducer, effector, chromatin modifiers and remodeling proteins, allowing cell cycle delay, DNA repair or induction of senescence or apoptosis. An early DDR-event includes the epigenetic phosphorylation of the histone variant H2AX on serine 139 of the C-termini, so-called gammaH2AX. GammaH2AX foci detected by immunolabeling on interphase nuclei have been largely studied; nonetheless gammaH2AX signals on mitotic chromosomes are less understood. The CHO9 cell line is a subclone of CHO (Chinese hamster ovary) cells with original and rearranged Z chromosomes originated during cell line transformation. As a result, homologous chromosome regions have been relocated in different Z-chromosomes. In a first quantitative analysis of gammaH2AX signals on immunolabeled mitotic chromosomes of cytocentrifuged metaphase spreads, we reported that gammaH2AX139 signals of both control and bleomycin-exposed cultures showed statistically equal distribution between CHO9 homologous chromosome regions, suggesting a possible dependence on the structure/function of chromatin. We have also demonstrated that bleomycin-induced gammaH2AX foci map preferentially to DNA replicating domains in CHO9 interphase nuclei. With the aim of understanding the role of gammaH2AX signals on metaphase chromosomes, the relation between 5-ethynyl-2'-deoxyuridine (EdU) labeled replicating chromosome regions and gammaH2AX signals in immunolabeled cytocentrifuged metaphase spreads from control and bleomycin-treated CHO9 cultures was analyzed in the present work. A quantitative analysis of colocalization between EdU and gammaH2AX signals based on the calculation of the Replication Related Damage Distribution Index (RDDI) on confocal metaphase images was performed. RDDI revealed a colocalization between EdU and gammaH2AX signals both in control and bleomycin-treated CHO9 metaphases, suggesting that replication may be involved in H2AX phosphorylation. The possible mechanisms implicated are discussed.
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24
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Loss of Stat6 affects chromatin condensation in intestinal epithelial cells causing diverse outcome in murine models of inflammation-associated and sporadic colon carcinogenesis. Oncogene 2018; 38:1787-1801. [PMID: 30353167 PMCID: PMC6756235 DOI: 10.1038/s41388-018-0551-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/16/2018] [Accepted: 09/28/2018] [Indexed: 12/19/2022]
Abstract
While great advances have been achieved regarding the genetic basis of colorectal cancer, the complex role of cell–cell communication and cytokine-induced signaling during its pathogenesis remains less understood. Signal transducer and activator of transcription 6 (Stat6) is the main transcription factor of interleukin-4 (IL-4) signaling and its participation in the development of various tumor types has been already reported. Here we aimed to examine the contribution of Stat6 in intestinal epithelial cells (IEC) in mouse models of intestinal carcinogenesis. Wild-type (WT), Stat6 knockout (Stat6−/−), and intestinal epithelial cell-specific IL-4Rα knockout (Il-4rαΔIEC) mice were subjected to colitis-associated (AOM/DSS) and colitis-independent (sporadic) carcinogenesis. IEC proliferation, apoptosis and RNA expression were evaluated by immunohistochemical, immunoblot, and RT-PCR analysis. We found that Stat6−/− mice developed more tumors in the colitis-associated carcinogenesis model. This was accompanied by a more pronounced inflammatory response during colitis and an elevated Stat3-dependent proliferation of IEC. Increased sensitivity to DSS-induced colitis was caused by elevated cell death in response to the initial carcinogen exposure as Stat6 deficiency led to increased chromatin compaction affecting DNA damage response in IEC upon treatment with alkylating agents independently of IL-4Rα engagement. Thus, loss of Stat6 caused more severe colitis and increased tumor load, however loss-of-initiated Stat6−/− IEC prevented tumor formation in the absence of overt inflammation. Our data unravel unexpected IL-4-independent functions of Stat6 in chromatin compaction in intestinal epithelial cells ultimately providing both tumor suppressive as well as tumor promoting effects in different models of intestinal tumorigenesis.
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25
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Abstract
Constitutive heterochromatin is a major component of the eukaryotic nucleus and is essential for the maintenance of genome stability. Highly concentrated at pericentromeric and telomeric domains, heterochromatin is riddled with repetitive sequences and has evolved specific ways to compartmentalize, silence, and repair repeats. The delicate balance between heterochromatin epigenetic maintenance and cellular processes such as mitosis and DNA repair and replication reveals a highly dynamic and plastic chromatin domain that can be perturbed by multiple mechanisms, with far-reaching consequences for genome integrity. Indeed, heterochromatin dysfunction provokes genetic turmoil by inducing aberrant repeat repair, chromosome segregation errors, transposon activation, and replication stress and is strongly implicated in aging and tumorigenesis. Here, we summarize the general principles of heterochromatin structure and function, discuss the importance of its maintenance for genome integrity, and propose that more comprehensive analyses of heterochromatin roles in tumorigenesis will be integral to future innovations in cancer treatment.
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Affiliation(s)
- Aniek Janssen
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - Serafin U. Colmenares
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - Gary H. Karpen
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
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26
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Fortuny A, Polo SE. The response to DNA damage in heterochromatin domains. Chromosoma 2018; 127:291-300. [PMID: 29594515 PMCID: PMC6440646 DOI: 10.1007/s00412-018-0669-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 10/24/2022]
Abstract
Eukaryotic genomes are organized into chromatin, divided into structurally and functionally distinct euchromatin and heterochromatin compartments. The high level of compaction and the abundance of repeated sequences in heterochromatin pose multiple challenges for the maintenance of genome stability. Cells have evolved sophisticated and highly controlled mechanisms to overcome these constraints. Here, we summarize recent findings on how the heterochromatic state influences DNA damage formation, signaling, and repair. By focusing on distinct heterochromatin domains in different eukaryotic species, we highlight the heterochromatin contribution to the compartmentalization of DNA damage repair in the cell nucleus and to the repair pathway choice. We also describe the diverse chromatin alterations associated with the DNA damage response in heterochromatin domains and present our current understanding of their regulatory mechanisms. Finally, we discuss the biological significance and the evolutionary conservation of these processes.
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Affiliation(s)
- Anna Fortuny
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Paris Diderot University, Paris, France
| | - Sophie E Polo
- Epigenetics and Cell Fate Centre, UMR7216 CNRS, Paris Diderot University, Paris, France.
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Lee CC, Hsieh TS. Wuho/WDR4 deficiency inhibits cell proliferation and induces apoptosis via DNA damage in mouse embryonic fibroblasts. Cell Signal 2018; 47:16-26. [PMID: 29574139 DOI: 10.1016/j.cellsig.2018.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/16/2018] [Accepted: 03/19/2018] [Indexed: 12/27/2022]
Abstract
Wuho known as WDR4 encodes a highly conserved WD40-repeat protein, which has known homologues of WDR4 in human and mouse. Wuho-FEN1 interaction may have a critical role in the growth and development, and in the maintenance of genome stability. However, how Wuho gene deletion contributes to cell growth inhibition and apoptosis is still unknown. We utilized CAGGCre-ER transgenic mice have a tamoxifen-inducible cre-mediated recombination cassette to prepare primary mouse embryonic fibroblasts (MEFs) with Wuho deficiency. We have demonstrated that Wuho deficiency would induces γH2AX protein level elevation, heterochromatin relaxation and DNA damage down-stream sequences, including p53 activation, caspase-mediated apoptotic pathway, and p21-mediated G2/M cell cycle arrest.
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Affiliation(s)
- Chi-Chiu Lee
- Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Academia Road, Sec. 2, Nangang, Taipei 11529, Taiwan.
| | - Tao-Shih Hsieh
- Institute of Cellular and Organismic Biology, Academia Sinica, No. 128, Academia Road, Sec. 2, Nangang, Taipei 11529, Taiwan; Department of Biochemistry, Duke University, Durham, NC, United States
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28
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Chang SC, Lai YC, Chen YC, Wang NK, Wang WS, Lai JI. CBX3/heterochromatin protein 1 gamma is significantly upregulated in patients with non-small cell lung cancer. Asia Pac J Clin Oncol 2017; 14:e283-e288. [PMID: 29124886 DOI: 10.1111/ajco.12820] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/04/2017] [Indexed: 12/17/2022]
Abstract
AIM Lung cancer is typically categorized into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). NSCLC comprises of the majority of lung cancer with a poor prognosis in advanced cases. Transcriptional profiling studies, including microarrays and RNA-sequencing studies, have significantly enriched our knowledge of gene expression patterns in NSCLC. A recent transcriptional profiling study identified high prevalence of CBX3/HP1-gamma upregulation in human NSCLC samples. CBX3/HP1-gamma is an isoform of the heterochromatin protein 1 family, which plays a role in heterochromatin formation and is linked to cancer. METHODS We examined lung cancer samples from our hospital using immunohistochemistry for CBX3/HP1-gamma staining. We also analyzed publicly available databases of NSCLC transcriptional profiling to validate our results. RESULTS We identified a high prevalence (77.2%) of samples with positive CBX3/HP1-gamma staining by immunohistochemistry in NSCLC patient samples. Independently, we queried a publicly available dataset (GSE40419) containing RNA-seq data from 77 patients. Upregulation of CBX3/HP1-gamma in tumor samples was present in 60.2% of the patients. A similar correlation was also observed in the The Cancer Genome Atlas (TCGA) database. Interestingly, we discovered a highly significant association between positive CBX3/HP1-gamma staining and EGFR mutation in our patient samples (40 of 42 patients, P < 0.001). Treatment of EGFR mutant NSCLC cell lines with the EGFR inhibitor gefitinib failed to yield a change in CBX/HP1-gamma expression, suggesting that CBX/HP1-gamma expression may be independent of EGFR downstream signaling. CONCLUSION We report a significant upregulation of CBX3/HP1-gamma in NSCLC patients, and also a possible relationship between CBX3/HP1-gamma expression and EGFR mutation.
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Affiliation(s)
- Shih-Chieh Chang
- School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Division of Chest Medicine, Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, Republic of China
| | - Yi-Chun Lai
- School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Division of Chest Medicine, Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, Republic of China.,Institute of Hospital and Health Care Administration, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Yen-Chung Chen
- School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Division of Pathology, Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, Republic of China
| | - Nai-Kuan Wang
- Division of Chest Medicine, Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, Republic of China
| | - Wei-Shu Wang
- School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, Republic of China
| | - Jiun-I Lai
- School of Medicine, National Yang-Ming University, Taipei, Taiwan, Republic of China.,Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan, Republic of China.,Division of Medical Oncology, Department of Oncology, Taipei Veterans General Hospital, Taiwan
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Drosophila Histone Demethylase KDM4A Has Enzymatic and Non-enzymatic Roles in Controlling Heterochromatin Integrity. Dev Cell 2017; 42:156-169.e5. [PMID: 28743002 DOI: 10.1016/j.devcel.2017.06.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 03/21/2017] [Accepted: 06/16/2017] [Indexed: 11/23/2022]
Abstract
Eukaryotic genomes are broadly divided between gene-rich euchromatin and the highly repetitive heterochromatin domain, which is enriched for proteins critical for genome stability and transcriptional silencing. This study shows that Drosophila KDM4A (dKDM4A), previously characterized as a euchromatic histone H3 K36 demethylase and transcriptional regulator, predominantly localizes to heterochromatin and regulates heterochromatin position-effect variegation (PEV), organization of repetitive DNAs, and DNA repair. We demonstrate that dKDM4A demethylase activity is dispensable for PEV. In contrast, dKDM4A enzymatic activity is required to relocate heterochromatic double-strand breaks outside the domain, as well as for organismal survival when DNA repair is compromised. Finally, DNA damage triggers dKDM4A-dependent changes in the levels of H3K56me3, suggesting that dKDM4A demethylates this heterochromatic mark to facilitate repair. We conclude that dKDM4A, in addition to its previously characterized role in euchromatin, utilizes both enzymatic and structural mechanisms to regulate heterochromatin organization and functions.
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30
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Li QL, Lei PJ, Zhao QY, Li L, Wei G, Wu M. Epigenomic analysis in a cell-based model reveals the roles of H3K9me3 in breast cancer transformation. Epigenomics 2017; 9:1077-1092. [DOI: 10.2217/epi-2016-0183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Aim: Epigenetic marks are critical regulators of chromatin and gene activity. Their roles in normal physiology and disease states, including cancer development, still remain elusive. Herein, the epigenomic change of H3K9me3, as well as its potential impacts on gene activity and genome stability, was investigated in an in vitro breast cancer transformation model. Methods: The global H3K9me3 level was studied with western blotting. The distribution of H3K9me3 on chromatin and gene expression was studied with ChIP-Seq and RNA-Seq, respectively. Results: The global H3K9me3 level decreases during transformation and its distribution on chromatin is reprogrammed. By combining with TCGA data, we identified 67 candidate oncogenes, among which five genes are totally novel. Our analysis further links H3K9me3 with transposon activity, and suggests H3K9me3 reduction increases the cell’s sensitivity to DNA damage reagents. Conclusion: H3K9me3 reduction is possibly related with breast cancer transformation by regulating gene expression and chromatin stability during transformation.
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Affiliation(s)
- Qing-Lan Li
- Hubei Key Laboratory of Cell Homeostasis, Hubei Key Laboratory of Developmentally Originated Disease, Department of Biochemistry & Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Pin-Ji Lei
- Hubei Key Laboratory of Cell Homeostasis, Hubei Key Laboratory of Developmentally Originated Disease, Department of Biochemistry & Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Quan-Yi Zhao
- Hubei Key Laboratory of Cell Homeostasis, Hubei Key Laboratory of Developmentally Originated Disease, Department of Biochemistry & Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Lianyun Li
- Hubei Key Laboratory of Cell Homeostasis, Hubei Key Laboratory of Developmentally Originated Disease, Department of Biochemistry & Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Gang Wei
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute of Computational Biology, Shanghai Institute for Biological Science, Chinese Academy of Sciences, Shanghai 200031, China
| | - Min Wu
- Hubei Key Laboratory of Cell Homeostasis, Hubei Key Laboratory of Developmentally Originated Disease, Department of Biochemistry & Molecular Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
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31
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Bártová E, Malyšková B, Komůrková D, Legartová S, Suchánková J, Krejčí J, Kozubek S. Function of heterochromatin protein 1 during DNA repair. PROTOPLASMA 2017; 254:1233-1240. [PMID: 28236007 DOI: 10.1007/s00709-017-1090-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 02/14/2017] [Indexed: 05/04/2023]
Abstract
This review focuses on the function of heterochromatin protein HP1 in response to DNA damage. We specifically outline the regulatory mechanisms in which HP1 and its interacting partners are involved. HP1 protein subtypes (HP1α, HP1β, and HP1γ) are the main components of constitutive heterochromatin, and HP1α and HP1β in particular are responsible for heterochromatin maintenance. The recruitment of these proteins to DNA lesions is also important from the perspective of proper DNA repair mechanisms. For example, HP1α is necessary for the binding of the main DNA damage-related protein 53BP1 at DNA repair foci, which are positive not only for the HP1α protein but also for the RAD51 protein, a component of DNA repair machinery. The HP1β protein also appears in monomeric form in DNA lesions together with the evolutionarily well-conserved protein called proliferating cell nuclear antigen (PCNA). The role of HP1 in DNA lesions is also mediated via the Kap1 transcription repressor. Taken together, these results indicate that the function of HP1 after DNA injury depends strongly on the kinetics of other DNA repair-related factors and their post-translational modifications, such as the phosphorylation of Kap-1.
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Affiliation(s)
- Eva Bártová
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic.
| | - Barbora Malyšková
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Denisa Komůrková
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Soňa Legartová
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Jana Suchánková
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Jana Krejčí
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Stanislav Kozubek
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
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32
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Raurell-Vila H, Bosch-Presegue L, Gonzalez J, Kane-Goldsmith N, Casal C, Brown JP, Marazuela-Duque A, Singh PB, Serrano L, Vaquero A. An HP1 isoform-specific feedback mechanism regulates Suv39h1 activity under stress conditions. Epigenetics 2017; 12:166-175. [PMID: 28059589 DOI: 10.1080/15592294.2016.1278096] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The presence of H3K9me3 and heterochromatin protein 1 (HP1) are hallmarks of heterochromatin conserved in eukaryotes. The spreading and maintenance of H3K9me3 is effected by the functional interplay between the H3K9me3-specific histone methyltransferase Suv39h1 and HP1. This interplay is complex in mammals because the three HP1 isoforms, HP1α, β, and γ, are thought to play a redundant role in Suv39h1-dependent deposition of H3K9me3 in pericentric heterochromatin (PCH). Here, we demonstrate that despite this redundancy, HP1α and, to a lesser extent, HP1γ have a closer functional link to Suv39h1, compared to HP1β. HP1α and γ preferentially interact in vivo with Suv39h1, regulate its dynamics in heterochromatin, and increase Suv39h1 protein stability through an inhibition of MDM2-dependent Suv39h1-K87 polyubiquitination. The reverse is also observed, where Suv39h1 increases HP1α stability compared HP1β and γ. The interplay between Suv39h1 and HP1 isoforms appears to be relevant under genotoxic stress. Specifically, loss of HP1α and γ isoforms inhibits the upregulation of Suv39h1 and H3K9me3 that is observed under stress conditions. Reciprocally, Suv39h1 deficiency abrogates stress-dependent upregulation of HP1α and γ, and enhances HP1β levels. Our work defines a specific role for HP1 isoforms in regulating Suv39h1 function under stress via a feedback mechanism that likely regulates heterochromatin formation.
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Affiliation(s)
- Helena Raurell-Vila
- a Chromatin Biology Laboratory, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigació Biomèdica de Bellvitge (IDIBELL) , L'Hospitalet de Llobregat, Barcelona , Spain
| | - Laia Bosch-Presegue
- a Chromatin Biology Laboratory, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigació Biomèdica de Bellvitge (IDIBELL) , L'Hospitalet de Llobregat, Barcelona , Spain.,b Tissue Repair and Regeneration Group , Department of Systems Biology , Universitat de Vic, Universitat Central de Catalunya , Vic , Spain
| | - Jessica Gonzalez
- a Chromatin Biology Laboratory, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigació Biomèdica de Bellvitge (IDIBELL) , L'Hospitalet de Llobregat, Barcelona , Spain
| | - Noriko Kane-Goldsmith
- c Department of Genetics , Human Genetics Institute, Rutgers University , Piscataway , NJ , USA
| | - Carmen Casal
- d Microcopy Unit, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigació Biomèdica de Bellvitge (IDIBELL) , L'Hospitalet de Llobregat, Barcelona , Spain
| | - Jeremy P Brown
- e Fächerverbund Anatomie, Institut für Zell- und Neurobiologie, Charite - Universitätsmedizin , Berlin , Germany
| | - Anna Marazuela-Duque
- a Chromatin Biology Laboratory, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigació Biomèdica de Bellvitge (IDIBELL) , L'Hospitalet de Llobregat, Barcelona , Spain
| | - Prim B Singh
- e Fächerverbund Anatomie, Institut für Zell- und Neurobiologie, Charite - Universitätsmedizin , Berlin , Germany.,f Natural Sciences and Psychology, John Moores University , Liverpool , UK
| | - Lourdes Serrano
- c Department of Genetics , Human Genetics Institute, Rutgers University , Piscataway , NJ , USA
| | - Alejandro Vaquero
- a Chromatin Biology Laboratory, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigació Biomèdica de Bellvitge (IDIBELL) , L'Hospitalet de Llobregat, Barcelona , Spain
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33
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Heterochromatin and the molecular mechanisms of ‘parent-of-origin’ effects in animals. J Biosci 2016; 41:759-786. [DOI: 10.1007/s12038-016-9650-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Chen Y, Zhu WG. Biological function and regulation of histone and non-histone lysine methylation in response to DNA damage. Acta Biochim Biophys Sin (Shanghai) 2016; 48:603-16. [PMID: 27217472 DOI: 10.1093/abbs/gmw050] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 04/21/2016] [Indexed: 02/07/2023] Open
Abstract
DNA damage response (DDR) signaling network is initiated to protect cells from various exogenous and endogenous damage resources. Timely and accurate regulation of DDR proteins is required for distinct DNA damage repair pathways. Post-translational modifications of histone and non-histone proteins play a vital role in the DDR factor foci formation and signaling pathway. Phosphorylation, ubiquitylation, SUMOylation, neddylation, poly(ADP-ribosyl)ation, acetylation, and methylation are all involved in the spatial-temporal regulation of DDR, among which phosphorylation and ubiquitylation are well studied. Studies in the past decade also revealed extensive roles of lysine methylation in response to DNA damage. Lysine methylation is finely regulated by plenty of lysine methyltransferases, lysine demethylases, and can be recognized by proteins with chromodomain, plant homeodomain, Tudor domain, malignant brain tumor domain, or proline-tryptophan-tryptophan-proline domain. In this review, we outline the dynamics and regulation of histone lysine methylation at canonical (H3K4, H3K9, H3K27, H3K36, H3K79, and H4K20) and non-canonical sites after DNA damage, and discuss their context-specific functions in DDR protein recruitment or extraction, chromatin environment establishment, and transcriptional regulation. We also present the emerging advances of lysine methylation in non-histone proteins during DDR.
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Affiliation(s)
- Yongcan Chen
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China Peking University-Tsinghua University Center for Life Sciences, Beijing 100191, China
| | - Wei-Guo Zhu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), State Key Laboratory of Natural and Biomimetic Drugs, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, Peking University Health Science Center, Beijing 100191, China Peking University-Tsinghua University Center for Life Sciences, Beijing 100191, China School of Medicine, Shenzhen University, Shenzhen 518060, China
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35
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Feng YL, Xiang JF, Kong N, Cai XJ, Xie AY. Buried territories: heterochromatic response to DNA double-strand breaks. Acta Biochim Biophys Sin (Shanghai) 2016; 48:594-602. [PMID: 27151295 DOI: 10.1093/abbs/gmw033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/28/2016] [Indexed: 12/22/2022] Open
Abstract
Cellular response to DNA double-strand breaks (DSBs), the most deleterious type of DNA damage, is highly influenced by higher-order chromatin structure in eukaryotic cells. Compared with euchromatin, the compacted structure of heterochromatin not only protects heterochromatic DNA from damage, but also adds an extra layer of control over the response to DSBs occurring in heterochromatin. One key step in this response is the decondensation of heterochromatin structure. This decondensation process facilitates the DNA damage signaling and promotes proper heterochromatic DSB repair, thus helping to prevent instability of heterochromatic regions of genomes. This review will focus on the functions of the ataxia telangiectasia mutated (ATM) signaling cascade involving ATM, heterochromatin protein 1 (HP1), Krüppel-associated box (KRAB)-associated protein-1 (KAP-1), tat-interacting protein 60 (Tip60), and many other protein factors in DSB-induced decondensation of heterochromatin and subsequent repair of heterochromatic DSBs. As some subsets of DSBs may be repaired in heterochromatin independently of the ATM signaling, a possible repair model is also proposed for ATM-independent repair of these heterochromatic DSBs.
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Affiliation(s)
- Yi-Li Feng
- Key Laboratory of Surgery of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, China Institute of Translational Medicine, Zhejiang University, Hangzhou 310029, China
| | - Ji-Feng Xiang
- Key Laboratory of Surgery of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, China Institute of Translational Medicine, Zhejiang University, Hangzhou 310029, China
| | - Na Kong
- Key Laboratory of Surgery of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, China Institute of Translational Medicine, Zhejiang University, Hangzhou 310029, China
| | - Xiu-Jun Cai
- Key Laboratory of Surgery of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, China
| | - An-Yong Xie
- Key Laboratory of Surgery of Zhejiang Province, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou 310016, China Institute of Translational Medicine, Zhejiang University, Hangzhou 310029, China
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36
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Abstract
Organism viability relies on the stable maintenance of specific chromatin landscapes, established during development, that shape cell functions and identities by driving distinct gene expression programs. Yet epigenome maintenance is challenged during transcription, replication, and repair of DNA damage, all of which elicit dynamic changes in chromatin organization. Here, we review recent advances that have shed light on the specialized mechanisms contributing to the restoration of epigenome structure and function after DNA damage in the mammalian cell nucleus. By drawing a parallel with epigenome maintenance during replication, we explore emerging concepts and highlight open issues in this rapidly growing field. In particular, we present our current knowledge of molecular players that support the coordinated maintenance of genome and epigenome integrity in response to DNA damage, and we highlight how nuclear organization impacts genome stability. Finally, we discuss possible functional implications of epigenome plasticity in response to genotoxic stress.
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Affiliation(s)
- Juliette Dabin
- Epigenome Integrity Group, UMR 7216 CNRS, Paris Diderot University, Sorbonne Paris Cité, 75013 Paris Cedex 13, France
| | - Anna Fortuny
- Epigenome Integrity Group, UMR 7216 CNRS, Paris Diderot University, Sorbonne Paris Cité, 75013 Paris Cedex 13, France
| | - Sophie E Polo
- Epigenome Integrity Group, UMR 7216 CNRS, Paris Diderot University, Sorbonne Paris Cité, 75013 Paris Cedex 13, France.
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37
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Gilmore JM, Sardiu ME, Groppe BD, Thornton JL, Liu X, Dayebgadoh G, Banks CA, Slaughter BD, Unruh JR, Workman JL, Florens L, Washburn MP. WDR76 Co-Localizes with Heterochromatin Related Proteins and Rapidly Responds to DNA Damage. PLoS One 2016; 11:e0155492. [PMID: 27248496 PMCID: PMC4889050 DOI: 10.1371/journal.pone.0155492] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/30/2016] [Indexed: 12/21/2022] Open
Abstract
Proteins that respond to DNA damage play critical roles in normal and diseased states in human biology. Studies have suggested that the S. cerevisiae protein CMR1/YDL156w is associated with histones and is possibly associated with DNA repair and replication processes. Through a quantitative proteomic analysis of affinity purifications here we show that the human homologue of this protein, WDR76, shares multiple protein associations with the histones H2A, H2B, and H4. Furthermore, our quantitative proteomic analysis of WDR76 associated proteins demonstrated links to proteins in the DNA damage response like PARP1 and XRCC5 and heterochromatin related proteins like CBX1, CBX3, and CBX5. Co-immunoprecipitation studies validated these interactions. Next, quantitative imaging studies demonstrated that WDR76 was recruited to laser induced DNA damage immediately after induction, and we compared the recruitment of WDR76 to laser induced DNA damage to known DNA damage proteins like PARP1, XRCC5, and RPA1. In addition, WDR76 co-localizes to puncta with the heterochromatin proteins CBX1 and CBX5, which are also recruited to DNA damage but much less intensely than WDR76. This work demonstrates the chromatin and DNA damage protein associations of WDR76 and demonstrates the rapid response of WDR76 to laser induced DNA damage.
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Affiliation(s)
- Joshua M. Gilmore
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Mihaela E. Sardiu
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Brad D. Groppe
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Janet L. Thornton
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Xingyu Liu
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Gerald Dayebgadoh
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Charles A. Banks
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Brian D. Slaughter
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Jay R. Unruh
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Jerry L. Workman
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
| | - Michael P. Washburn
- Stowers Institute for Medical Research, Kansas City, MO, 64110, United States of America
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, Kansas, 66160, United States of America
- * E-mail:
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38
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Han C, Srivastava AK, Cui T, Wang QE, Wani AA. Differential DNA lesion formation and repair in heterochromatin and euchromatin. Carcinogenesis 2015; 37:129-38. [PMID: 26717995 DOI: 10.1093/carcin/bgv247] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/13/2015] [Indexed: 11/15/2022] Open
Abstract
Discretely orchestrated chromatin condensation is important for chromosome protection from DNA damage. However, it is still unclear how different chromatin states affect the formation and repair of nucleotide excision repair (NER) substrates, e.g. ultraviolet (UV)-induced cyclobutane pyrimidine dimers (CPD) and the pyrimidine (6-4) pyrimidone photoproducts (6-4PP), as well as cisplatin-induced intrastrand crosslinks (Pt-GG). Here, by using immunofluorescence and chromatin immunoprecipitation assays, we have demonstrated that CPD, which cause minor distortion of DNA double helix, can be detected in both euchromatic and heterochromatic regions, while 6-4PP and Pt-GG, which cause major distortion of DNA helix, can exclusively be detected in euchromatin, indicating that the condensed chromatin environment specifically interferes with the formation of these DNA lesions. Mechanistic investigation revealed that the class III histone deacetylase SIRT1 is responsible for restricting the formation of 6-4PP and Pt-GG in cells, probably by facilitating the maintenance of highly condensed heterochromatin. In addition, we also showed that the repair of CPD in heterochromatin is slower than that in euchromatin, and DNA damage binding protein 2 (DDB2) can promote the removal of CPD from heterochromatic region. In summary, our data provide evidence for differential formation and repair of DNA lesions that are substrates of NER. Both the sensitivity of DNA to damage and the kinetics of repair can be affected by the underlying level of chromatin compaction.
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Affiliation(s)
| | - Amit Kumar Srivastava
- James Cancer Hospital and Solove Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | | | - Qi-En Wang
- Department of Radiology and James Cancer Hospital and Solove Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Altaf A Wani
- Department of Radiology and James Cancer Hospital and Solove Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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Genome-wide redistribution of H3K27me3 is linked to genotoxic stress and defective growth. Proc Natl Acad Sci U S A 2015; 112:E6339-48. [PMID: 26578794 DOI: 10.1073/pnas.1511377112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
H3K9 methylation directs heterochromatin formation by recruiting multiple heterochromatin protein 1 (HP1)-containing complexes that deacetylate histones and methylate cytosine bases in DNA. In Neurospora crassa, a single H3K9 methyltransferase complex, called the DIM-5,-7,-9, CUL4, DDB1 Complex (DCDC), is required for normal growth and development. DCDC-deficient mutants are hypersensitive to the genotoxic agent methyl methanesulfonate (MMS), but the molecular basis of genotoxic stress is unclear. We found that both the MMS sensitivity and growth phenotypes of DCDC-deficient strains are suppressed by mutation of embryonic ectoderm development or Su-(var)3-9; E(z); Trithorax (set)-7, encoding components of the H3K27 methyltransferase Polycomb repressive complex-2 (PRC2). Trimethylated histone H3K27 (H3K27me3) undergoes genome-wide redistribution to constitutive heterochromatin in DCDC- or HP1-deficient mutants, and introduction of an H3K27 missense mutation is sufficient to rescue phenotypes of DCDC-deficient strains. Accumulation of H3K27me3 in heterochromatin does not compensate for silencing; rather, strains deficient for both DCDC and PRC2 exhibit synthetic sensitivity to the topoisomerase I inhibitor Camptothecin and accumulate γH2A at heterochromatin. Together, these data suggest that PRC2 modulates the response to genotoxic stress.
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Çelik S, Li Y, O’Neill C. The effect of DNA damage on the pattern of immune-detectable DNA methylation in mouse embryonic fibroblasts. Exp Cell Res 2015; 339:20-34. [DOI: 10.1016/j.yexcr.2015.08.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 07/31/2015] [Accepted: 08/27/2015] [Indexed: 12/21/2022]
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Qin T, Si J, Raynal NJM, Wang X, Gharibyan V, Ahmed S, Hu X, Jin C, Lu Y, Shu J, Estecio MR, Jelinek J, Issa JPJ. Epigenetic synergy between decitabine and platinum derivatives. Clin Epigenetics 2015; 7:97. [PMID: 26366234 PMCID: PMC4567801 DOI: 10.1186/s13148-015-0131-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/01/2015] [Indexed: 01/25/2023] Open
Abstract
Background Aberrant epigenetic silencing of tumor suppressor genes has been recognized as a driving force in cancer. Epigenetic drugs such as the DNA methylation inhibitor decitabine reactivate genes and are effective in myeloid leukemia, but resistance often develops and efficacy in solid tumors is limited. To improve their clinical efficacy, we searched among approved anti-cancer drugs for an epigenetic synergistic combination with decitabine. Results We used the YB5 cell line, a clonal derivative of the SW48 colon cancer cell line that contains a single copy of a hypermethylated cytomegalovirus (CMV) promoter driving green fluorescent protein (GFP) to screen for drug-induced gene reactivation and synergy with decitabine. None of the 16 anti-cancer drugs tested had effects on their own. However, in combination with decitabine, platinum compounds showed striking synergy in activating GFP. This was dose dependent, observed both in concurrent and sequential combinations, and also seen with other alkylating agents. Clinically achievable concentrations of carboplatin at (25 μM) and decitabine reactivated GFP in 28 % of the YB5 cells as compared to 15 % with decitabine alone. Epigenetic synergy was also seen at endogenously hypermethylated tumor suppressor genes such as MLH1 and PDLIM4. Genome-wide studies showed that reactivation of hypermethylated genes by the combination was significantly better than that induced by decitabine alone or carboplatin alone. Platinum compounds did not enhance decitabine-induced hypomethylation. Rather, we found significantly inhibited HP1α expression by carboplatin and the combination. This was accompanied by increased histone H3 lysine 4 (H3K4) trimethylation and histone H3 lysine 9 (H3K9) acetylation at reactivated genes (P < 0.0001) and reduced occupancy by methyl-binding proteins including MeCP2 and methyl-CpG-binding domain protein 2 (MBD2) (P < 0.0001). Conclusions Our results suggest that the combination of decitabine with platinum analogs shows epigenetic synergy that might be exploited in the treatment of different cancers. Electronic supplementary material The online version of this article (doi:10.1186/s13148-015-0131-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Taichun Qin
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Jiali Si
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Noël J-M Raynal
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA.,Fels Institute for Cancer Research and Molecular Biology, Temple University, 3307 North Broad Street, Rm 154, PAHB, Philadelphia, PA 19140 USA
| | - Xiaodan Wang
- Harbin Institute of Hematology & Oncology, Harbin, 150010 China
| | - Vazganush Gharibyan
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Saira Ahmed
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Xin Hu
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Chunlei Jin
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Yue Lu
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA.,Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Jingmin Shu
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Marcos Rh Estecio
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA.,Department of Epigenetics and Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA
| | - Jaroslav Jelinek
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA.,Fels Institute for Cancer Research and Molecular Biology, Temple University, 3307 North Broad Street, Rm 154, PAHB, Philadelphia, PA 19140 USA
| | - Jean-Pierre J Issa
- Department of Leukemia, University of Texas MD Anderson Cancer Center, Houston, TX 77030 USA.,Fels Institute for Cancer Research and Molecular Biology, Temple University, 3307 North Broad Street, Rm 154, PAHB, Philadelphia, PA 19140 USA
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Alagoz M, Katsuki Y, Ogiwara H, Ogi T, Shibata A, Kakarougkas A, Jeggo P. SETDB1, HP1 and SUV39 promote repositioning of 53BP1 to extend resection during homologous recombination in G2 cells. Nucleic Acids Res 2015. [PMID: 26206670 PMCID: PMC4652757 DOI: 10.1093/nar/gkv722] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent studies have shown that homologous recombination (HR) requires chromatin repression as well as relaxation at DNA double strand breaks (DSBs). HP1 and SUV39H1/2 are repressive factors essential for HR. Here, we identify SETDB1 as an additional compacting factor promoting HR. Depletion of HP1, SUV39, SETDB1 or BRCA1 confer identical phenotypes. The repressive factors, like BRCA1, are dispensable for the initiation of resection but promote the extension step causing diminished RPA or RAD51 foci and HR in irradiated G2 cells. Depletion of the compacting factors does not inhibit BRCA1 recruitment but at 8 h post IR, BRCA1 foci are smaller and aberrantly positioned compared to control cells. BRCA1 promotes 53BP1 repositioning to the periphery of enlarged foci and formation of a devoid core with BRCA1 becoming enlarged and localized internally to 53BP1. Depletion of the compacting factors precludes these changes at irradiation-induced foci. Thus, the repressive factors are required for BRCA1 function in promoting the repositioning of 53BP1 during HR. Additionally, depletion of these repressive factors in undamaged cells causes diminished sister chromatid association at centromeric sequences. We propose a model for how these findings may be functionally linked.
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Affiliation(s)
- Meryem Alagoz
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Yoko Katsuki
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Hideaki Ogiwara
- Division of Genome Biology, National Cancer Centre Japan Research Institute, Tokyo, 104-0045, Japan
| | - Tomoo Ogi
- Department of Molecular Medicine, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, 852-8523, Japan
| | - Atsushi Shibata
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
| | - Andreas Kakarougkas
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK Department of Biology, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835, Egypt
| | - Penny Jeggo
- University of Sussex Genome Damage and Stability Centre, East Sussex, BN19RQ, UK
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Izhar L, Adamson B, Ciccia A, Lewis J, Pontano-Vaites L, Leng Y, Liang AC, Westbrook TF, Harper JW, Elledge SJ. A Systematic Analysis of Factors Localized to Damaged Chromatin Reveals PARP-Dependent Recruitment of Transcription Factors. Cell Rep 2015; 11:1486-500. [PMID: 26004182 DOI: 10.1016/j.celrep.2015.04.053] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/16/2015] [Accepted: 04/25/2015] [Indexed: 01/09/2023] Open
Abstract
Localization to sites of DNA damage is a hallmark of DNA damage response (DDR) proteins. To identify DDR factors, we screened epitope-tagged proteins for localization to sites of chromatin damaged by UV laser microirradiation and found >120 proteins that localize to damaged chromatin. These include the BAF tumor suppressor complex and the amyotrophic lateral sclerosis (ALS) candidate protein TAF15. TAF15 contains multiple domains that bind damaged chromatin in a poly-(ADP-ribose) polymerase (PARP)-dependent manner, suggesting a possible role as glue that tethers multiple PAR chains together. Many positives were transcription factors; > 70% of randomly tested transcription factors localized to sites of DNA damage, and of these, ∼90% were PARP dependent for localization. Mutational analyses showed that localization to damaged chromatin is DNA-binding-domain dependent. By examining Hoechst staining patterns at damage sites, we see evidence of chromatin decompaction that is PARP dependent. We propose that PARP-regulated chromatin remodeling at sites of damage allows transient accessibility of DNA-binding proteins.
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Affiliation(s)
- Lior Izhar
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Britt Adamson
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alberto Ciccia
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Genetics and Development, Columbia University, New York, NY 10032, USA
| | - Jedd Lewis
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Laura Pontano-Vaites
- Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Yumei Leng
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Anthony C Liang
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Thomas F Westbrook
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Department of Molecular and Human Genetics, and Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - J Wade Harper
- Department of Cell Biology, Harvard University Medical School, Boston, MA 02115, USA
| | - Stephen J Elledge
- Department of Genetics, Harvard University Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute; Division of Genetics, Brigham and Women's Hospital, Boston, MA 02115, USA.
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Osterwald S, Deeg KI, Chung I, Parisotto D, Wörz S, Rohr K, Erfle H, Rippe K. PML induces compaction, TRF2 depletion and DNA damage signaling at telomeres and promotes their alternative lengthening. J Cell Sci 2015; 128:1887-1900. [DOI: 10.1242/jcs.148296] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
ABSTRACT
The alternative lengthening of telomeres (ALT) mechanism allows cancer cells to escape senescence and apoptosis in the absence of active telomerase. A characteristic feature of this pathway is the assembly of ALT-associated promyelocytic leukemia (PML) nuclear bodies (APBs) at telomeres. Here, we dissected the role of APBs in a human ALT cell line by performing an RNA interference screen using an automated 3D fluorescence microscopy platform and advanced 3D image analysis. We identified 29 proteins that affected APB formation, which included proteins involved in telomere and chromatin organization, protein sumoylation and DNA repair. By integrating and extending these findings, we found that APB formation induced clustering of telomere repeats, telomere compaction and concomitant depletion of the shelterin protein TRF2 (also known as TERF2). These APB-dependent changes correlated with the induction of a DNA damage response at telomeres in APBs as evident by a strong enrichment of the phosphorylated form of the ataxia telangiectasia mutated (ATM) kinase. Accordingly, we propose that APBs promote telomere maintenance by inducing a DNA damage response in ALT-positive tumor cells through changing the telomeric chromatin state to trigger ATM phosphorylation.
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Affiliation(s)
- Sarah Osterwald
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Katharina I. Deeg
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Inn Chung
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Daniel Parisotto
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
| | - Stefan Wörz
- Department of Bioinformatics and Functional Genomics, Biomedical Computer Vision Group, University of Heidelberg & DKFZ, BioQuant, IPMB, 69120 Heidelberg, Germany
| | - Karl Rohr
- Department of Bioinformatics and Functional Genomics, Biomedical Computer Vision Group, University of Heidelberg & DKFZ, BioQuant, IPMB, 69120 Heidelberg, Germany
| | - Holger Erfle
- ViroQuant-CellNetworks RNAi Screening Facility, University of Heidelberg & BioQuant, 69120 Heidelberg, Germany
| | - Karsten Rippe
- Research Group Genome Organization & Function, Deutsches Krebsforschungszentrum (DKFZ) & BioQuant, 69120 Heidelberg, Germany
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Lee YH, Liu X, Qiu F, O’Connor TR, Yen Y, Ann DK. HP1β is a biomarker for breast cancer prognosis and PARP inhibitor therapy. PLoS One 2015; 10:e0121207. [PMID: 25769025 PMCID: PMC4358987 DOI: 10.1371/journal.pone.0121207] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/28/2015] [Indexed: 11/23/2022] Open
Abstract
Members of the heterochromatin protein 1 family (HP1α, β and γ) are mostly associated with heterochromatin and play important roles in gene regulation and DNA damage response. Altered expression of individual HP1 subtype has profound impacts on cell proliferation and tumorigenesis. We analyzed the expression profile of HP1 family by data mining using a published microarray data set coupled with retrospective immunohistochemistry analyses of archived breast cancer biospecimens. We found that the patient group overexpressing HP1β mRNA is associated with poorly differentiated breast tumors and with a significantly lower survival rate. Immunohistochemical staining against HP1α, HP1β and HP1γ shows that respective HP1 expression level is frequently altered in breast cancers. 57.4 - 60.1% of samples examined showed high HP1β expression and 39.9 - 42.6 % of examined tumors showed no or low expression of each HP1 subtype. Interestingly, comparative analysis on HP1 expression profile and breast cancer markers revealed a positive correlation between the respective expression level of all three HP1 subtypes and Ki-67, a cell proliferation and well-known breast cancer marker. To explore the effect of individual HP1 on PARP inhibitor therapy for breast cancer, MCF7 breast cancer cells and individually HP1-depleted MCF7 cells were treated with PARP inhibitor ABT-888 with or without carboplatin. Notably, HP1β-knockdown cells are hypersensitive to the PARP inhibitor ABT-888 alone and its combination with carboplatin. In summary, while increased HP1β expression is associated with the poor prognosis in breast cancer, compromised HP1β abundance may serve as a useful predictive marker for chemotherapy, including PARP inhibitors against breast cancer.
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Affiliation(s)
- Young-Ho Lee
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
- * E-mail: (YL); (DA)
| | - Xiyong Liu
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - Fuming Qiu
- Department of Medical Oncology, Second Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
| | - Timothy R. O’Connor
- Department of Cancer Biology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - Yun Yen
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
| | - David K. Ann
- Department of Molecular Pharmacology, Beckman Research Institute, City of Hope, Duarte, California, United States of America
- * E-mail: (YL); (DA)
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Stixová L, Sehnalová P, Legartová S, Suchánková J, Hrušková T, Kozubek S, Sorokin DV, Matula P, Raška I, Kovařík A, Fulneček J, Bártová E. HP1β-dependent recruitment of UBF1 to irradiated chromatin occurs simultaneously with CPDs. Epigenetics Chromatin 2014; 7:39. [PMID: 25587355 PMCID: PMC4293114 DOI: 10.1186/1756-8935-7-39] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 12/12/2014] [Indexed: 11/24/2022] Open
Abstract
Background The repair of spontaneous and induced DNA lesions is a multistep process. Depending on the type of injury, damaged DNA is recognized by many proteins specifically involved in distinct DNA repair pathways. Results We analyzed the DNA-damage response after ultraviolet A (UVA) and γ irradiation of mouse embryonic fibroblasts and focused on upstream binding factor 1 (UBF1), a key protein in the regulation of ribosomal gene transcription. We found that UBF1, but not nucleolar proteins RPA194, TCOF, or fibrillarin, was recruited to UVA-irradiated chromatin concurrently with an increase in heterochromatin protein 1β (HP1β) level. Moreover, Förster Resonance Energy Transfer (FRET) confirmed interaction between UBF1 and HP1β that was dependent on a functional chromo shadow domain of HP1β. Thus, overexpression of HP1β with a deleted chromo shadow domain had a dominant-negative effect on UBF1 recruitment to UVA-damaged chromatin. Transcription factor UBF1 also interacted directly with DNA inside the nucleolus but no interaction of UBF1 and DNA was confirmed outside the nucleolus, where UBF1 recruitment to DNA lesions appeared simultaneously with cyclobutane pyrimidine dimers; this occurrence was cell-cycle-independent. Conclusions We propose that the simultaneous presence and interaction of UBF1 and HP1β at DNA lesions is activated by the presence of cyclobutane pyrimidine dimers and mediated by the chromo shadow domain of HP1β. This might have functional significance for nucleotide excision repair. Electronic supplementary material The online version of this article (doi:10.1186/1756-8935-7-39) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Lenka Stixová
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Petra Sehnalová
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Soňa Legartová
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Jana Suchánková
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Tereza Hrušková
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Stanislav Kozubek
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Dmitry V Sorokin
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic ; Faculty of Informatics, Masaryk University, Botanická 68a, 602 00 Brno, Czech Republic
| | - Pavel Matula
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic ; Faculty of Informatics, Masaryk University, Botanická 68a, 602 00 Brno, Czech Republic
| | - Ivan Raška
- Institute of Cellular Biology and Pathology, the First Faculty of Medicine, Charles University in Prague, Albertov 4, 128 01 Prague, Czech Republic
| | - Aleš Kovařík
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Jaroslav Fulneček
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
| | - Eva Bártová
- Academy of Sciences of the Czech Republic, Institute of Biophysics, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
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Burgess RC, Burman B, Kruhlak MJ, Misteli T. Activation of DNA damage response signaling by condensed chromatin. Cell Rep 2014; 9:1703-1717. [PMID: 25464843 DOI: 10.1016/j.celrep.2014.10.060] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 09/11/2014] [Accepted: 10/25/2014] [Indexed: 12/20/2022] Open
Abstract
The DNA damage response (DDR) occurs in the context of chromatin, and architectural features of chromatin have been implicated in DNA damage signaling and repair. Whereas a role of chromatin decondensation in the DDR is well established, we show here that chromatin condensation is integral to DDR signaling. We find that, in response to DNA damage chromatin regions transiently expand before undergoing extensive compaction. Using a protein-chromatin-tethering system to create defined chromatin domains, we show that interference with chromatin condensation results in failure to fully activate DDR. Conversely, forced induction of local chromatin condensation promotes ataxia telangiectasia mutated (ATM)- and ATR-dependent activation of upstream DDR signaling in a break-independent manner. Whereas persistent chromatin compaction enhanced upstream DDR signaling from irradiation-induced breaks, it reduced recovery and survival after damage. Our results demonstrate that chromatin condensation is sufficient for activation of DDR signaling and is an integral part of physiological DDR signaling.
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Affiliation(s)
- Rebecca C Burgess
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bharat Burman
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; Program in Cell, Molecular and Developmental Biology, Sackler School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA
| | - Michael J Kruhlak
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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RAD6 promotes homologous recombination repair by activating the autophagy-mediated degradation of heterochromatin protein HP1. Mol Cell Biol 2014; 35:406-16. [PMID: 25384975 DOI: 10.1128/mcb.01044-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Efficient DNA double-strand break (DSB) repair is critical for the maintenance of genome stability. Unrepaired or misrepaired DSBs cause chromosomal rearrangements that can result in severe consequences, such as tumorigenesis. RAD6 is an E2 ubiquitin-conjugating enzyme that plays a pivotal role in repairing UV-induced DNA damage. Here, we present evidence that RAD6 is also required for DNA DSB repair via homologous recombination (HR) by specifically regulating the degradation of heterochromatin protein 1α (HP1α). Our study indicates that RAD6 physically interacts with HP1α and ubiquitinates HP1α at residue K154, thereby promoting HP1α degradation through the autophagy pathway and eventually leading to an open chromatin structure that facilitates efficient HR DSB repair. Furthermore, bioinformatics studies have indicated that the expression of RAD6 and HP1α exhibits an inverse relationship and correlates with the survival rate of patients.
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49
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Seridi L, Ryu T, Ravasi T. Dynamic epigenetic control of highly conserved noncoding elements. PLoS One 2014; 9:e109326. [PMID: 25289637 PMCID: PMC4188601 DOI: 10.1371/journal.pone.0109326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 09/11/2014] [Indexed: 11/19/2022] Open
Abstract
Background Many noncoding genomic loci have remained constant over long evolutionary periods, suggesting that they are exposed to strong selective pressures. The molecular functions of these elements have been partially elucidated, but the fundamental reason for their extreme conservation is still unknown. Results To gain new insights into the extreme selection of highly conserved noncoding elements (HCNEs), we used a systematic analysis of multi-omic data to study the epigenetic regulation of such elements during the development of Drosophila melanogaster. At the sequence level, HCNEs are GC-rich and have a characteristic oligomeric composition. They have higher levels of stable nucleosome occupancy than their flanking regions, and lower levels of mononucleosomes and H3.3, suggesting that these regions reside in compact chromatin. Furthermore, these regions showed remarkable modulations in histone modification and the expression levels of adjacent genes during development. Although HCNEs are primarily initiated late in replication, about 10% were related to early replication origins. Finally, HCNEs showed strong enrichment within lamina-associated domains. Conclusion HCNEs have distinct and protective sequence properties, undergo dynamic epigenetic regulation, and appear to be associated with the structural components of the chromatin, replication origins, and nuclear matrix. These observations indicate that such elements are likely to have essential cellular functions, and offer insights into their epigenetic properties.
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Affiliation(s)
- Loqmane Seridi
- Division of Biological and Environmental Sciences & Engineering, Division of Applied Mathematics and Computer Sciences, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Taewoo Ryu
- Division of Biological and Environmental Sciences & Engineering, Division of Applied Mathematics and Computer Sciences, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- * E-mail: (T. Ryu); (T. Ravasi)
| | - Timothy Ravasi
- Division of Biological and Environmental Sciences & Engineering, Division of Applied Mathematics and Computer Sciences, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Medicine, Division of Genetics, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (T. Ryu); (T. Ravasi)
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Homeodomain-interacting protein kinase 2 regulates DNA damage response through interacting with heterochromatin protein 1γ. Oncogene 2014; 34:3463-73. [PMID: 25151962 DOI: 10.1038/onc.2014.278] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 07/01/2014] [Accepted: 07/23/2014] [Indexed: 12/19/2022]
Abstract
Homeodomain-interacting protein kinase 2 (HIPK2) is a potential tumor suppressor that has a crucial role in the DNA damage response (DDR) by regulating cell-cycle checkpoint activation and apoptosis. However, it is unclear whether HIPK2 exerts distinct roles in DNA damage repair. The aim of this study was to identify novel target molecule(s) of HIPK2, which mediates HIPK2-dependent DNA damage repair. HIPK2-knockdown human colon cancer cells (HCT116) or hipk1/hipk2 double-deficient mouse embryonic fibroblasts could not remove histone H2A.X phosphorylated at Ser139 (γH2A.X) after irradiation with a sublethal dose (10 J/m(2)) of ultraviolet (UV)-C, resulting in apoptosis. Knockdown of HIPK2 in p53-null HCT116 cells similarly promoted the UV-C-induced γH2A.X accumulation and apoptosis. Proteomic analysis of HIPK2-associated proteins using liquid chromatography-tandem mass spectrometry identified heterochromatin protein 1γ (HP1γ) as a novel target for HIPK2. Immunoprecipitation experiments with HCT116 cells expressing FLAG-tagged HIPK2 and one of the HA-tagged HP1 family members demonstrated that HIPK2 specifically associated with HP1γ, but not with HP1α or HP1β, through its chromo-shadow domain. Mutation of the HP1box motif (883-PTVSV-887) within HIPK2 abolished the association. HP1γ knockdown also enhanced accumulation of γH2A.X and apoptosis after sublethal UV-C irradiation. In vitro kinase assay demonstrated an HP1γ-phosphorylating activity of HIPK2. Sublethal UV-C irradiation phosphorylated HP1γ. This phosphorylation was absent in endogenous HIPK2-silenced cells with HIPK2 3'UTR siRNA. Overexpression of FLAG-HIPK2, but not the HP1box-mutated or kinase-dead HIPK2 mutant, in the HIPK2-silenced cells increased HP1γ binding to trimethylated (Lys9) histone H3 (H3K9me3), rescued the UV-C-induced phosphorylation of HP1γ, triggered release of HP1γ from histone H3K9me3 and suppressed γH2A.X accumulation. Our results suggest that HIPK2-dependent phosphorylation of HP1γ may participate in the regulation of dynamic interaction between HP1γ and histone H3K9me3 to promote DNA damage repair. This HIPK2/HP1γ pathway may uncover a new functional aspect of HIPK2 as a tumor suppressor.
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