1
|
Spracklin G, Abdennur N, Imakaev M, Chowdhury N, Pradhan S, Mirny LA, Dekker J. Diverse silent chromatin states modulate genome compartmentalization and loop extrusion barriers. Nat Struct Mol Biol 2023; 30:38-51. [PMID: 36550219 PMCID: PMC9851908 DOI: 10.1038/s41594-022-00892-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 11/01/2022] [Indexed: 12/24/2022]
Abstract
The relationships between chromosomal compartmentalization, chromatin state and function are poorly understood. Here by profiling long-range contact frequencies in HCT116 colon cancer cells, we distinguish three silent chromatin states, comprising two types of heterochromatin and a state enriched for H3K9me2 and H2A.Z that exhibits neutral three-dimensional interaction preferences and which, to our knowledge, has not previously been characterized. We find that heterochromatin marked by H3K9me3, HP1α and HP1β correlates with strong compartmentalization. We demonstrate that disruption of DNA methyltransferase activity greatly remodels genome compartmentalization whereby domains lose H3K9me3-HP1α/β binding and acquire the neutrally interacting state while retaining late replication timing. Furthermore, we show that H3K9me3-HP1α/β heterochromatin is permissive to loop extrusion by cohesin but refractory to CTCF binding. Together, our work reveals a dynamic structural and organizational diversity of the silent portion of the genome and establishes connections between the regulation of chromatin state and chromosome organization, including an interplay between DNA methylation, compartmentalization and loop extrusion.
Collapse
Affiliation(s)
- George Spracklin
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA.
- Department of Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Nezar Abdennur
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Maxim Imakaev
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Neil Chowdhury
- Program for Research in Mathematics, Engineering and Science for High School Students (PRIMES), MIT, Cambridge, MA, USA
| | - Sriharsa Pradhan
- Genome Biology Division, New England Biolabs, Inc., Ipswich, MA, USA
| | - Leonid A Mirny
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
| | - Job Dekker
- Department of Systems Biology, University of Massachusetts Medical School, Worcester, MA, USA.
- Howard Hughes Medical Institute, Chevy Chase, USA.
| |
Collapse
|
2
|
Gaspar AD, Cuddapah S. Nickel-induced alterations to chromatin structure and function. Toxicol Appl Pharmacol 2022; 457:116317. [PMID: 36400264 PMCID: PMC9722551 DOI: 10.1016/j.taap.2022.116317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/17/2022]
Abstract
Nickel (Ni), a heavy metal is prevalent in the atmosphere due to both natural and anthropogenic activities. Ni is a carcinogen implicated in the development of lung and nasal cancers in humans. Furthermore, Ni exposure is associated with a number of chronic lung diseases in humans including asthma, chronic bronchitis, emphysema, pulmonary fibrosis, pulmonary edema and chronic obstructive pulmonary disease (COPD). While Ni compounds are weak mutagens, a number of studies have demonstrated the potential of Ni to alter the epigenome, suggesting epigenomic dysregulation as an important underlying cause for its pathogenicity. In the eukaryotic nucleus, the DNA is organized in a three-dimensional (3D) space through assembly of higher order chromatin structures. Such an organization is critically important for transcription and other biological activities. Accumulating evidence suggests that by negatively affecting various cellular regulatory processes, Ni could potentially affect chromatin organization. In this review, we discuss the role of Ni in altering the chromatin architecture, which potentially plays a major role in Ni pathogenicity.
Collapse
Affiliation(s)
- Adrian Domnic Gaspar
- Division of Environmental Medicine, Department of Medicine, New York University Grossman School of Medicine, New York, NY 10010, USA
| | - Suresh Cuddapah
- Division of Environmental Medicine, Department of Medicine, New York University Grossman School of Medicine, New York, NY 10010, USA.
| |
Collapse
|
3
|
Velay F, Méteignier LV, Laloi C. You shall not pass! A Chromatin barrier story in plants. FRONTIERS IN PLANT SCIENCE 2022; 13:888102. [PMID: 36212303 PMCID: PMC9540200 DOI: 10.3389/fpls.2022.888102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/15/2022] [Indexed: 06/16/2023]
Abstract
As in other eukaryotes, the plant genome is functionally organized in two mutually exclusive chromatin fractions, a gene-rich and transcriptionally active euchromatin, and a gene-poor, repeat-rich, and transcriptionally silent heterochromatin. In Drosophila and humans, the molecular mechanisms by which euchromatin is preserved from heterochromatin spreading have been extensively studied, leading to the identification of insulator DNA elements and associated chromatin factors (insulator proteins), which form boundaries between chromatin domains with antagonistic features. In contrast, the identity of factors assuring such a barrier function remains largely elusive in plants. Nevertheless, several genomic elements and associated protein factors have recently been shown to regulate the spreading of chromatin marks across their natural boundaries in plants. In this minireview, we focus on recent findings that describe the spreading of chromatin and propose avenues to improve the understanding of how plant chromatin architecture and transitions between different chromatin domains are defined.
Collapse
Affiliation(s)
- Florent Velay
- Aix Marseille Université, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille (BIAM), Equipe de Luminy de Génétique et Biophysique des Plantes, Marseille, F-13009, France
| | - Louis-Valentin Méteignier
- Aix Marseille Université, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille (BIAM), Equipe de Luminy de Génétique et Biophysique des Plantes, Marseille, F-13009, France
- EA2106 Biomolécules et Biotechnologies Végétales, Université de Tours, Tours, France
| | - Christophe Laloi
- Aix Marseille Université, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille (BIAM), Equipe de Luminy de Génétique et Biophysique des Plantes, Marseille, F-13009, France
| |
Collapse
|
4
|
van Schaik T, Liu NQ, Manzo SG, Peric-Hupkes D, de Wit E, van Steensel B. CTCF and cohesin promote focal detachment of DNA from the nuclear lamina. Genome Biol 2022; 23:185. [PMID: 36050765 PMCID: PMC9438259 DOI: 10.1186/s13059-022-02754-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 08/22/2022] [Indexed: 01/23/2023] Open
Abstract
Background Lamina-associated domains (LADs) are large genomic regions that are positioned at the nuclear lamina. It has remained largely unclear what drives the positioning and demarcation of LADs. Because the insulator protein CTCF is enriched at LAD borders, it was postulated that CTCF binding could position some LAD boundaries, possibly through its function in stalling cohesin and hence preventing cohesin invading into the LAD. To test this, we mapped genome–nuclear lamina interactions in mouse embryonic stem cells after rapid depletion of CTCF and other perturbations of cohesin dynamics. Results CTCF and cohesin contribute to a sharp transition in lamina interactions at LAD borders, while LADs are maintained after depletion of these proteins, also at borders marked by CTCF. CTCF and cohesin may thus reinforce LAD borders, but do not position these. CTCF binding sites within LADs are locally detached from the lamina and enriched for accessible DNA and active histone modifications. Remarkably, despite lamina positioning being strongly correlated with genome inactivity, this DNA remains accessible after the local detachment is lost following CTCF depletion. At a chromosomal scale, cohesin depletion and cohesin stabilization by depletion of the unloading factor WAPL quantitatively affect lamina interactions, indicative of perturbed chromosomal positioning in the nucleus. Finally, while H3K27me3 is locally enriched at CTCF-marked LAD borders, we find no evidence for an interplay between CTCF and H3K27me3 on lamina interactions. Conclusions These findings illustrate that CTCF and cohesin are not primary determinants of LAD patterns. Rather, these proteins locally modulate NL interactions. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02754-3.
Collapse
Affiliation(s)
- Tom van Schaik
- Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Ning Qing Liu
- Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Stefano G Manzo
- Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Daan Peric-Hupkes
- Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands.,Present address: Annogen, Amsterdam, the Netherlands
| | - Elzo de Wit
- Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Bas van Steensel
- Oncode Institute and Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands. .,Department of Cell Biology, Erasmus University Medical Center, Rotterdam, the Netherlands.
| |
Collapse
|
5
|
Yan Z, Ji L, Huo X, Wang Q, Zhang Y, Wen B. G9a/GLP-sensitivity of H3K9me2 Demarcates Two Types of Genomic Compartments. GENOMICS, PROTEOMICS & BIOINFORMATICS 2020; 18:359-370. [PMID: 33285284 PMCID: PMC8242262 DOI: 10.1016/j.gpb.2020.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/01/2020] [Accepted: 10/26/2020] [Indexed: 11/30/2022]
Abstract
In the nucleus, chromatin is folded into hierarchical architecture that is tightly linked to various nuclear functions. However, the underlying molecular mechanisms that confer these architectures remain incompletely understood. Here, we investigated the functional roles of H3 lysine 9 dimethylation (H3K9me2), one of the abundant histone modifications, in three-dimensional (3D) genome organization. Unlike in mouse embryonic stem cells, inhibition of methyltransferases G9a and GLP in differentiated cells eliminated H3K9me2 predominantly at A-type (active) genomic compartments, and the level of residual H3K9me2 modifications was strongly associated with B-type (inactive) genomic compartments. Furthermore, chemical inhibition of G9a/GLP in mouse hepatocytes led to decreased chromatin-nuclear lamina interactions mainly at G9a/GLP-sensitive regions, increased degree of genomic compartmentalization, and up-regulation of hundreds of genes that were associated with alterations of the 3D chromatin. Collectively, our data demonstrated essential roles of H3K9me2 in 3D genome organization.
Collapse
Affiliation(s)
- Zixiang Yan
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Luzhang Ji
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Xiangru Huo
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Qianfeng Wang
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Yuwen Zhang
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Bo Wen
- MOE Key Laboratory of Metabolism and Molecular Medicine, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, and Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China; State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Fudan University, Shanghai 200438, China.
| |
Collapse
|
6
|
Myasoedova VA, Sukhorukov V, Grechko AV, Zhang D, Romanenko E, Orekhov V, Orekhov AN. Inhibitors of DNA Methylation and Histone Deacetylation as Epigenetically Active Drugs for Anticancer Therapy. Curr Pharm Des 2020; 25:635-641. [PMID: 30950345 DOI: 10.2174/1381612825666190405144026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/29/2019] [Indexed: 12/12/2022]
Abstract
Gene expression is regulated and tightly controlled by epigenetic mechanisms. Alterations of these mechanisms are frequently observed in various diseases, particularly, in various types of cancer. Malignant transformation is caused by the impairment of the mechanisms of cell differentiation and cell cycle control associated with epigenetic changes. Altered patterns of epigenetic modification associated with malignancies can potentially be reversed by some agents that act on the key proteins responsible for DNA/histone modification and chromatin remodelling. Examples of such substances include the inhibitors of DNA methyltransferases or histone deacetylase. During the recent years, a number of such substances have been evaluated as potential therapeutic agents against certain types of cancer in preclinical and clinical studies, and some of them have been approved for treatment of hematological cancers. Application of epidrugs for therapy of solid tumors remains, however, more challenging. In this review, we summarize the current knowledge on the most studied mechanisms of epigenetic modification and the available epigenetically active drugs.
Collapse
Affiliation(s)
- Veronika A Myasoedova
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Moscow 125315, Russian Federation
| | - Vasily Sukhorukov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Moscow 125315, Russian Federation.,Research Institute of Human Morphology, Moscow 117418, Russian Federation
| | - Andrey V Grechko
- Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, Moscow 109240, Russian Federation
| | - Dongwei Zhang
- Traditional Chinese Medicine School, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Elena Romanenko
- Belozersky Institute of Physical and Clinical Biology, Moscow, Russian Federation
| | - Vawain Orekhov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Moscow 125315, Russian Federation
| | - Alexander N Orekhov
- Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, Moscow 125315, Russian Federation.,Institute for Atherosclerosis Research, Skolkovo Innovative Center, Moscow 121609, Russian Federation
| |
Collapse
|
7
|
Çelik-Uzuner S. Enhanced immunological detection of epigenetic modifications of DNA in healthy and cancerous cells by fluorescence microscopy. Microsc Res Tech 2019; 82:1962-1972. [PMID: 31429164 DOI: 10.1002/jemt.23365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 08/05/2019] [Accepted: 08/06/2019] [Indexed: 12/21/2022]
Abstract
Epigenetic modifications of DNA, including methylation, hydroxymethylation, formylation, and carboxylation of cytosines, are proposed to function in gene regulation during reproduction and development. Changes in cytosine methylation are associated with a range of diseases, such as cancer. Immunofluorescence uses specific antibodies to quantitatively detect the global amount of cytosine modifications by fluorescence microscopy. The most critical stage of immunofluorescence is the antigen retrieval to remove the protein content around the DNA, allowing specific antibodies to bind to DNA epitopes. Acid treatments have commonly been used for antigen retrieval. Previously, trypsin was added after acid in the protocol, which increased the amount of detectable DNA methylation. In this study, the protocol was further enhanced by the addition of pepsin, which is able to target charged hydrophobic amino acids in proteins, unlike trypsin, which breaks positive hydrophilic amino acids. The global levels of cytosine modifications in CF-1, HeLa, and AR42J cells were compared using this protocol. In all cells, the sequential treatment of trypsin and pepsin increased the specificity of the staining. With the synergistic effect of the two enzymes, it is possible to target different protein groups packaging DNA molecules and removing them effectively. The findings suggest that this revised protocol can be conveniently used for each cytosine modification in the cells examined, and should be optimized for other cells. These new antigen retrieval conditions may more accurately detect the changes in cytosine modifications during development and in diseases.
Collapse
Affiliation(s)
- Selcen Çelik-Uzuner
- Faculty of Science, Department of Molecular Biology and Genetics, Karadeniz Technical University, Trabzon, Turkey
| |
Collapse
|
8
|
Current epigenetic aspects the clinical kidney researcher should embrace. Clin Sci (Lond) 2017; 131:1649-1667. [DOI: 10.1042/cs20160596] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/17/2017] [Accepted: 04/19/2017] [Indexed: 02/06/2023]
Abstract
Chronic kidney disease (CKD), affecting 10–12% of the world’s adult population, is associated with a considerably elevated risk of serious comorbidities, in particular, premature vascular disease and death. Although a wide spectrum of causative factors has been identified and/or suggested, there is still a large gap of knowledge regarding the underlying mechanisms and the complexity of the CKD phenotype. Epigenetic factors, which calibrate the genetic code, are emerging as important players in the CKD-associated pathophysiology. In this article, we review some of the current knowledge on epigenetic modifications and aspects on their role in the perturbed uraemic milieu, as well as the prospect of applying epigenotype-based diagnostics and preventive and therapeutic tools of clinical relevance to CKD patients. The practical realization of such a paradigm will require that researchers apply a holistic approach, including the full spectrum of the epigenetic landscape as well as the variability between and within tissues in the uraemic milieu.
Collapse
|
9
|
Abstract
The dramatic re-organization of the cancer cell nucleus creates telltale morphological features critical for pathological staging of tumors. In addition, the changes to the mutational and epigenetic landscape in cancer cells alter the structure and stability of the genome and directly contribute to malignancy. DNA methylation is one of the best studied epigenetic changes in cancer, as nearly every type of cancer studied shows a loss of DNA methylation spread across most of the genome. This global hypomethylation is accompanied by hypermethylation at distinct loci, and much of the work on DNA methylation in cancer has focused on how local changes contribute to gene expression. However, the emerging picture is that the changes to DNA methylation in cancer cells has little direct effect on gene expression but instead impacts the organization of the genome in the nucleus. Several recent studies that take a broad view of the cancer epigenome find that the most profound changes to the cancer methylome are spread across large segments of the genome, and that the focal changes are reflective of a whole reorganization of epigenome. Hallmarks of nuclear reorganization in cancer are found in the long regions of chromatin marked by histone methylation (LOCKs) and nuclear lamina interactions (LADs). In this review, we focus on a novel perspective that DNA methylation changes in cancer impact the global structure of heterochromatin, LADs and LOCKs, and how these global changes, in turn, contribute to gene expression changes and genomic stability.
Collapse
Affiliation(s)
| | - Kirsten C Sadler
- Program in Biology, New York University Abu Dhabi,Abu Dhabi, United Arab Emirates
| |
Collapse
|
10
|
Christogianni A, Chatzantonaki E, Soupsana K, Giannios I, Platania A, Politou AS, Georgatos S. Heterochromatin remodeling in embryonic stem cells proceeds through stochastic de-stabilization of regional steady-states. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:661-673. [DOI: 10.1016/j.bbagrm.2017.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 12/19/2016] [Accepted: 01/19/2017] [Indexed: 01/10/2023]
|
11
|
Potential energy landscapes identify the information-theoretic nature of the epigenome. Nat Genet 2017; 49:719-729. [PMID: 28346445 PMCID: PMC5565269 DOI: 10.1038/ng.3811] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/13/2017] [Indexed: 12/11/2022]
Abstract
Epigenetics is the study of biochemical modifications carrying information independent of DNA sequence, which are heritable through cell division. In 1940, Waddington coined the term "epigenetic landscape" as a metaphor for pluripotency and differentiation, but methylation landscapes have not yet been rigorously computed. Using principles from statistical physics and information theory, we derive epigenetic energy landscapes from whole-genome bisulfite sequencing (WGBS) data that enable us to quantify methylation stochasticity genome-wide using Shannon's entropy, associating it with chromatin structure. Moreover, we consider the Jensen-Shannon distance between sample-specific energy landscapes as a measure of epigenetic dissimilarity and demonstrate its effectiveness for discerning epigenetic differences. By viewing methylation maintenance as a communications system, we introduce methylation channels and show that higher-order chromatin organization can be predicted from their informational properties. Our results provide a fundamental understanding of the information-theoretic nature of the epigenome that leads to a powerful approach for studying its role in disease and aging.
Collapse
|
12
|
Epigenomic reprogramming during pancreatic cancer progression links anabolic glucose metabolism to distant metastasis. Nat Genet 2017; 49:367-376. [PMID: 28092686 DOI: 10.1038/ng.3753] [Citation(s) in RCA: 319] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022]
Abstract
During the progression of pancreatic ductal adenocarcinoma (PDAC), heterogeneous subclonal populations emerge that drive primary tumor growth, regional spread, distant metastasis, and patient death. However, the genetics of metastases largely reflects that of the primary tumor in untreated patients, and PDAC driver mutations are shared by all subclones. This raises the possibility that an epigenetic process might operate during metastasis. Here we report large-scale reprogramming of chromatin modifications during the natural evolution of distant metastasis. Changes were targeted to thousands of large chromatin domains across the genome that collectively specified malignant traits, including euchromatin and large organized chromatin histone H3 lysine 9 (H3K9)-modified (LOCK) heterochromatin. Remarkably, distant metastases co-evolved a dependence on the oxidative branch of the pentose phosphate pathway (oxPPP), and oxPPP inhibition selectively reversed reprogrammed chromatin, malignant gene expression programs, and tumorigenesis. These findings suggest a model whereby linked metabolic-epigenetic programs are selected for enhanced tumorigenic fitness during the evolution of distant metastasis.
Collapse
|
13
|
CUDR promotes liver cancer stem cell growth through upregulating TERT and C-Myc. Oncotarget 2016; 6:40775-98. [PMID: 26513297 PMCID: PMC4747368 DOI: 10.18632/oncotarget.5805] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 08/20/2015] [Indexed: 01/01/2023] Open
Abstract
Cancer up-regulated drug resistant (CUDR) is a novel non-coding RNA gene. Herein, we demonstrate excessive CUDR cooperates with excessive CyclinD1 or PTEN depletion to accelerate liver cancer stem cells growth and liver stem cell malignant transformation in vitro and in vivo. Mechanistically, we reveal the decrease of PTEN in cells may lead to increase binding capacity of CUDR to CyclinD1. Therefore, CUDR-CyclinD1 complex loads onto the long noncoding RNA H19 promoter region that may lead to reduce the DNA methylation on H19 promoter region and then to enhance the H19 expression. Strikingly, the overexpression of H19 increases the binding of TERT to TERC and reduces the interplay between TERT with TERRA, thus enhancing the cell telomerase activity and extending the telomere length. On the other hand, insulator CTCF recruits the CUDR-CyclinD1 complx to form the composite CUDR-CyclinD1-insulator CTCF complex which occupancied on the C-myc gene promoter region, increasing the outcome of oncogene C-myc. Ultimately, excessive TERT and C-myc lead to liver cancer stem cell and hepatocyte-like stem cell malignant proliferation. To understand the novel functions of long noncoding RNA CUDR will help in the development of new liver cancer therapeutic and diagnostic approaches.
Collapse
|
14
|
Isbel L, Prokopuk L, Wu H, Daxinger L, Oey H, Spurling A, Lawther AJ, Hale MW, Whitelaw E. Wiz binds active promoters and CTCF-binding sites and is required for normal behaviour in the mouse. eLife 2016; 5. [PMID: 27410475 PMCID: PMC4977153 DOI: 10.7554/elife.15082] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 07/09/2016] [Indexed: 12/26/2022] Open
Abstract
We previously identified Wiz in a mouse screen for epigenetic modifiers. Due to its known association with G9a/GLP, Wiz is generally considered a transcriptional repressor. Here, we provide evidence that it may also function as a transcriptional activator. Wiz levels are high in the brain, but its function and direct targets are unknown. ChIP-seq was performed in adult cerebellum and Wiz peaks were found at promoters and transcription factor CTCF binding sites. RNA-seq in Wiz mutant mice identified genes differentially regulated in adult cerebellum and embryonic brain. In embryonic brain most decreased in expression and included clustered protocadherin genes. These also decreased in adult cerebellum and showed strong Wiz ChIP-seq enrichment. Because a precise pattern of protocadherin gene expression is required for neuronal development, behavioural tests were carried out on mutant mice, revealing an anxiety-like phenotype. This is the first evidence of a role for Wiz in neural function. DOI:http://dx.doi.org/10.7554/eLife.15082.001
Collapse
Affiliation(s)
- Luke Isbel
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Lexie Prokopuk
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Haoyu Wu
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Lucia Daxinger
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia.,Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Harald Oey
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Alex Spurling
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Adam J Lawther
- Department of Psychology and Counselling, La Trobe University, Melbourne, Australia.,School of Psychology and Public Health, La Trobe University, Melbourne, Australia
| | - Matthew W Hale
- Department of Psychology and Counselling, La Trobe University, Melbourne, Australia.,School of Psychology and Public Health, La Trobe University, Melbourne, Australia
| | - Emma Whitelaw
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| |
Collapse
|
15
|
Wei Y, Wu H. Measuring the spatial correlations of protein binding sites. Bioinformatics 2016; 32:1766-72. [PMID: 26861822 DOI: 10.1093/bioinformatics/btw058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 01/25/2016] [Indexed: 11/14/2022] Open
Abstract
MOTIVATION Understanding the interactions of different DNA binding proteins is a crucial first step toward deciphering gene regulatory mechanism. With advances of high-throughput sequencing technology such as ChIP-seq, the genome-wide binding sites of many proteins have been profiled under different biological contexts. It is of great interest to quantify the spatial correlations of the binding sites, such as their overlaps, to provide information for the interactions of proteins. Analyses of the overlapping patterns of binding sites have been widely performed, mostly based on ad hoc methods. Due to the heterogeneity and the tremendous size of the genome, such methods often lead to biased even erroneous results. RESULTS In this work, we discover a Simpson's paradox phenomenon in assessing the genome-wide spatial correlation of protein binding sites. Leveraging information from publicly available data, we propose a testing procedure for evaluating the significance of overlapping from a pair of proteins, which accounts for background artifacts and genome heterogeneity. Real data analyses demonstrate that the proposed method provide more biologically meaningful results. AVAILABILITY AND IMPLEMENTATION An R package is available at http://www.sta.cuhk.edu.hk/YWei/ChIPCor.html CONTACTS ywei@sta.cuhk.edu.hk or hao.wu@emory.edu SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Yingying Wei
- Department of Statistics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong and
| | - Hao Wu
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA 30322, USA
| |
Collapse
|
16
|
Gonzalez-Sandoval A, Gasser SM. On TADs and LADs: Spatial Control Over Gene Expression. Trends Genet 2016; 32:485-495. [PMID: 27312344 DOI: 10.1016/j.tig.2016.05.004] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 01/10/2023]
Abstract
The combinatorial action of transcription factors drives cell-type-specific gene expression patterns. However, transcription factor binding and gene regulation occur in the context of chromatin, which modulates DNA accessibility. High-resolution chromatin interaction maps have defined units of chromatin that are in spatial proximity, called topologically associated domains (TADs). TADs can be further classified based on expression activity, replication timing, or the histone marks or non-histone proteins associated with them. Independently, other chromatin domains have been defined by their likelihood to interact with non-DNA structures, such as the nuclear lamina. Lamina-associated domains (LADs) correlate with low gene expression and late replication timing. TADs and LADs have recently been evaluated with respect to cell-type-specific gene expression. The results shed light on the relevance of these forms of chromatin organization for transcriptional regulation, and address specifically how chromatin sequestration influences cell fate decisions during organismal development.
Collapse
Affiliation(s)
- Adriana Gonzalez-Sandoval
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; Faculty of Natural Sciences, University of Basel, Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; Faculty of Natural Sciences, University of Basel, Basel, Switzerland.
| |
Collapse
|
17
|
Dere E, Huse S, Hwang K, Sigman M, Boekelheide K. Intra- and inter-individual differences in human sperm DNA methylation. Andrology 2016; 4:832-42. [PMID: 27089098 DOI: 10.1111/andr.12170] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/06/2016] [Accepted: 01/13/2016] [Indexed: 12/20/2022]
Abstract
There is growing evidence that sperm DNA methylation is important in maintaining proper sperm health and function. Previous studies have associated sperm DNA methylation levels with sperm quality and function, however, little is known regarding the intra- and inter-individual variability in sperm methylation levels. This study characterizes this variation. Sperm epigenetic differences between successive semen samples from 12 patients were examined to identify the intra- and inter-individual differences globally across the genome, and in specifically defined genomic regions using the Illumina Infinium HumanMethylation450 BeadChips. Methylation analysis identified a bimodal distribution in the methylation levels that were non-uniformly distributed across the different genomic regions. The methylation levels were highly correlated in both the intra- and inter-individual comparisons. The intra-individual methylation levels were more highly correlated than the inter-individual comparison both globally and across the defined genomic regions, demonstrating that sperm DNA methylation levels are relatively stable between semen sample collections.
Collapse
Affiliation(s)
- E Dere
- Division of Urology, Rhode Island Hospital, Providence, RI, USA.,Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - S Huse
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| | - K Hwang
- Division of Urology, Rhode Island Hospital, Providence, RI, USA.,The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - M Sigman
- Division of Urology, Rhode Island Hospital, Providence, RI, USA.,The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - K Boekelheide
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA
| |
Collapse
|
18
|
Fu Y, Lv P, Yan G, Fan H, Cheng L, Zhang F, Dang Y, Wu H, Wen B. MacroH2A1 associates with nuclear lamina and maintains chromatin architecture in mouse liver cells. Sci Rep 2015; 5:17186. [PMID: 26603343 PMCID: PMC4658601 DOI: 10.1038/srep17186] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 10/26/2015] [Indexed: 12/26/2022] Open
Abstract
In the interphase nucleus, chromatin is organized into three-dimensional conformation to coordinate genome functions. The lamina-chromatin association is important to facilitate higher-order chromatin in mammalian cells, but its biological significances and molecular mechanisms remain poorly understood. One obstacle is that the list of lamina-associated proteins remains limited, presumably due to the inherent insolubility of lamina proteins. In this report, we identified 182 proteins associated with lamin B1 (a constitutive component of lamina) in mouse hepatocytes, by adopting virus-based proximity-dependent biotin identification. These proteins are functionally related to biological processes such as chromatin organization. As an example, we validated the association between lamin B1 and core histone macroH2A1, a histone associated with repressive chromatin. Furthermore, we mapped Lamina-associated domains (LADs) in mouse liver cells and found that boundaries of LADs are enriched for macroH2A. More interestingly, knocking-down of macroH2A1 resulted in the release of heterochromatin foci marked by histone lysine 9 trimethylation (H3K9me3) and the decondensation of global chromatin structure. However, down-regulation of lamin B1 led to redistribution of macroH2A1. Taken together, our data indicated that macroH2A1 is associated with lamina and is required to maintain chromatin architecture in mouse liver cells.
Collapse
Affiliation(s)
- Yuhua Fu
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Pin Lv
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Guoquan Yan
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Department of Chemistry, Fudan University, Shanghai, 200433
| | - Hui Fan
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Lu Cheng
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Feng Zhang
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yongjun Dang
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Hao Wu
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA 30322, USA
| | - Bo Wen
- Key Laboratory of Molecular Medicine of Ministry of Education and Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
- State Key Laboratory of Genetic Engineering and Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai 200438, China
| |
Collapse
|
19
|
Mosquera Orgueira A. Hidden among the crowd: differential DNA methylation-expression correlations in cancer occur at important oncogenic pathways. Front Genet 2015; 6:163. [PMID: 26029238 PMCID: PMC4429616 DOI: 10.3389/fgene.2015.00163] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 04/10/2015] [Indexed: 12/31/2022] Open
Abstract
DNA methylation is a frequent epigenetic mechanism that participates in transcriptional repression. Variations in DNA methylation with respect to gene expression are constant, and, for unknown reasons, some genes with highly methylated promoters are sometimes overexpressed. In this study we have analyzed the expression and methylation patterns of thousands of genes in five groups of cancer and normal tissue samples in order to determine local and genome-wide differences. We observed significant changes in global methylation-expression correlation in all the neoplasms, which suggests that differential correlation events are frequent in cancer. A focused analysis in the breast cancer cohort identified 1662 genes whose correlation varies significantly between normal and cancerous breast, but whose DNA methylation and gene expression patterns do not change substantially. These genes were enriched in cancer-related pathways and repressive chromatin features across various model cell lines, such as PRC2 binding and H3K27me3 marks. Substantial changes in methylation-expression correlation indicate that these genes are subject to epigenetic remodeling, where the differential activity of other factors break the expected relationship between both variables. Our findings suggest a complex regulatory landscape where a redistribution of local and large-scale chromatin repressive domains at differentially correlated genes (DCGs) creates epigenetic hotspots that modulate cancer-specific gene expression.
Collapse
|
20
|
Talamas JA, Capelson M. Nuclear envelope and genome interactions in cell fate. Front Genet 2015; 6:95. [PMID: 25852741 PMCID: PMC4365743 DOI: 10.3389/fgene.2015.00095] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/22/2015] [Indexed: 12/14/2022] Open
Abstract
The eukaryotic cell nucleus houses an organism’s genome and is the location within the cell where all signaling induced and development-driven gene expression programs are ultimately specified. The genome is enclosed and separated from the cytoplasm by the nuclear envelope (NE), a double-lipid membrane bilayer, which contains a large variety of trans-membrane and associated protein complexes. In recent years, research regarding multiple aspects of the cell nucleus points to a highly dynamic and coordinated concert of efforts between chromatin and the NE in regulation of gene expression. Details of how this concert is orchestrated and how it directs cell differentiation and disease are coming to light at a rapid pace. Here we review existing and emerging concepts of how interactions between the genome and the NE may contribute to tissue specific gene expression programs to determine cell fate.
Collapse
Affiliation(s)
- Jessica A Talamas
- Program in Epigenetics, Department of Cell and Developmental Biology, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Maya Capelson
- Program in Epigenetics, Department of Cell and Developmental Biology, Smilow Center for Translational Research, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| |
Collapse
|
21
|
Harr JC, Luperchio TR, Wong X, Cohen E, Wheelan SJ, Reddy KL. Directed targeting of chromatin to the nuclear lamina is mediated by chromatin state and A-type lamins. ACTA ACUST UNITED AC 2015; 208:33-52. [PMID: 25559185 PMCID: PMC4284222 DOI: 10.1083/jcb.201405110] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nuclear organization has been implicated in regulating gene activity. Recently, large developmentally regulated regions of the genome dynamically associated with the nuclear lamina have been identified. However, little is known about how these lamina-associated domains (LADs) are directed to the nuclear lamina. We use our tagged chromosomal insertion site system to identify small sequences from borders of fibroblast-specific variable LADs that are sufficient to target these ectopic sites to the nuclear periphery. We identify YY1 (Ying-Yang1) binding sites as enriched in relocating sequences. Knockdown of YY1 or lamin A/C, but not lamin A, led to a loss of lamina association. In addition, targeted recruitment of YY1 proteins facilitated ectopic LAD formation dependent on histone H3 lysine 27 trimethylation and histone H3 lysine di- and trimethylation. Our results also reveal that endogenous loci appear to be dependent on lamin A/C, YY1, H3K27me3, and H3K9me2/3 for maintenance of lamina-proximal positioning.
Collapse
Affiliation(s)
- Jennifer C Harr
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Teresa Romeo Luperchio
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Xianrong Wong
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Erez Cohen
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Sarah J Wheelan
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| | - Karen L Reddy
- Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205 Department of Biological Chemistry, Center for Epigenetics, and Department of Oncology Biostatistics and Bioinformatics, Johns Hopkins University, Baltimore, MD 21205
| |
Collapse
|
22
|
Epigenetic dysregulation by nickel through repressive chromatin domain disruption. Proc Natl Acad Sci U S A 2014; 111:14631-6. [PMID: 25246589 DOI: 10.1073/pnas.1406923111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Investigations into the genomic landscape of histone modifications in heterochromatic regions have revealed histone H3 lysine 9 dimethylation (H3K9me2) to be important for differentiation and maintaining cell identity. H3K9me2 is associated with gene silencing and is organized into large repressive domains that exist in close proximity to active genes, indicating the importance of maintenance of proper domain structure. Here we show that nickel, a nonmutagenic environmental carcinogen, disrupted H3K9me2 domains, resulting in the spreading of H3K9me2 into active regions, which was associated with gene silencing. We found weak CCCTC-binding factor (CTCF)-binding sites and reduced CTCF binding at the Ni-disrupted H3K9me2 domain boundaries, suggesting a loss of CTCF-mediated insulation function as a potential reason for domain disruption and spreading. We furthermore show that euchromatin islands, local regions of active chromatin within large H3K9me2 domains, can protect genes from H3K9me2-spreading-associated gene silencing. These results have major implications in understanding H3K9me2 dynamics and the consequences of chromatin domain disruption during pathogenesis.
Collapse
|
23
|
Lyons DB, Lomvardas S. Repressive histone methylation: a case study in deterministic versus stochastic gene regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:1373-84. [PMID: 24859457 DOI: 10.1016/j.bbagrm.2014.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/09/2014] [Accepted: 05/13/2014] [Indexed: 01/21/2023]
Abstract
Transcriptionally repressive histone lysine methylation is used by eukaryotes to tightly control cell fate. Here we explore the importance of this form of regulation in the control of clustered genes in the genome. Two distinctly regulated gene families with important roles in vertebrates are discussed, namely the Hox genes and olfactory receptor genes. Major recent advances in these two fields are compared and contrasted, with an emphasis on the roles of the two different forms of histone trimethylation. We discuss how this repression may impact both the transcriptional output of these loci and the way higher-order chromatin organization is related to their unique control.
Collapse
Affiliation(s)
- David B Lyons
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Stavros Lomvardas
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Anatomy, University of California San Francisco, CA 94920, USA.
| |
Collapse
|
24
|
Genome regulation at the peripheral zone: lamina associated domains in development and disease. Curr Opin Genet Dev 2014; 25:50-61. [PMID: 24556270 DOI: 10.1016/j.gde.2013.11.021] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 11/29/2013] [Indexed: 12/18/2022]
Abstract
The nuclear periphery has been implicated in gene regulation and it has been proposed that proximity to the nuclear lamina and inner nuclear membrane (INM) leads to gene repression. More recently, it appears that there is a correlation and interdependence between lamina associated domains (LADs), the epigenome and overall three-dimensional architecture of the genome. However, the mechanisms of such organization at the 'peripheral zone' and the functional significance of these associations are poorly understood. The role these domains play in development and disease is an active and exciting area of research, expanding our knowledge of how the three-dimensional (3D) genome is regulated.
Collapse
|
25
|
Hansen KD, Sabunciyan S, Langmead B, Nagy N, Curley R, Klein G, Klein E, Salamon D, Feinberg AP. Large-scale hypomethylated blocks associated with Epstein-Barr virus-induced B-cell immortalization. Genome Res 2013; 24:177-84. [PMID: 24068705 PMCID: PMC3912409 DOI: 10.1101/gr.157743.113] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Altered DNA methylation occurs ubiquitously in human cancer from the earliest measurable stages. A cogent approach to understanding the mechanism and timing of altered DNA methylation is to analyze it in the context of carcinogenesis by a defined agent. Epstein-Barr virus (EBV) is a human oncogenic herpesvirus associated with lymphoma and nasopharyngeal carcinoma, but also used commonly in the laboratory to immortalize human B-cells in culture. Here we have performed whole-genome bisulfite sequencing of normal B-cells, activated B-cells, and EBV-immortalized B-cells from the same three individuals, in order to identify the impact of transformation on the methylome. Surprisingly, large-scale hypomethylated blocks comprising two-thirds of the genome were induced by EBV immortalization but not by B-cell activation per se. These regions largely corresponded to hypomethylated blocks that we have observed in human cancer, and they were associated with gene-expression hypervariability, similar to human cancer, and consistent with a model of epigenomic change promoting tumor cell heterogeneity. We also describe small-scale changes in DNA methylation near CpG islands. These results suggest that methylation disruption is an early and critical step in malignant transformation.
Collapse
|
26
|
Timp W, Feinberg AP. Cancer as a dysregulated epigenome allowing cellular growth advantage at the expense of the host. Nat Rev Cancer 2013; 13:497-510. [PMID: 23760024 PMCID: PMC4636434 DOI: 10.1038/nrc3486] [Citation(s) in RCA: 410] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Although at the genetic level cancer is caused by diverse mutations, epigenetic modifications are characteristic of all cancers, from apparently normal precursor tissue to advanced metastatic disease, and these epigenetic modifications drive tumour cell heterogeneity. We propose a unifying model of cancer in which epigenetic dysregulation allows rapid selection for tumour cell survival at the expense of the host. Mechanisms involve both genetic mutations and epigenetic modifications that disrupt the function of genes that regulate the epigenome itself. Several exciting recent discoveries also point to a genome-scale disruption of the epigenome that involves large blocks of DNA hypomethylation, mutations of epigenetic modifier genes and alterations of heterochromatin in cancer (including large organized chromatin lysine modifications (LOCKs) and lamin-associated domains (LADs)), all of which increase epigenetic and gene expression plasticity. Our model suggests a new approach to cancer diagnosis and therapy that focuses on epigenetic dysregulation and has great potential for risk detection and chemoprevention.
Collapse
Affiliation(s)
- Winston Timp
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | | |
Collapse
|
27
|
Towbin BD, Gonzalez-Sandoval A, Gasser SM. Mechanisms of heterochromatin subnuclear localization. Trends Biochem Sci 2013; 38:356-63. [PMID: 23746617 DOI: 10.1016/j.tibs.2013.04.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/24/2013] [Accepted: 04/30/2013] [Indexed: 11/18/2022]
Abstract
Transcriptionally repressed heterochromatin becomes the dominant form of chromatin in most terminally differentiated cells. Moreover, in most cells, at least one class of heterochromatin is positioned adjacent to the nuclear lamina. Recent approaches have addressed the mechanism of heterochromatin localization, in order to determine whether spatial segregation contributes to gene repression. Findings in worms and human cells confirm a role for histone H3K9 methylation in heterochromatin positioning, identifying a modification that is also necessary for gene repression of worm transgenic arrays. These pathways appear to be conserved, although mutations in mammalian cells have weaker effects, possibly due to redundancy in positioning mechanisms. We propose a general model in which perinuclear anchoring is linked to an epigenetic propagation of the heterochromatic state, through histone modification.
Collapse
Affiliation(s)
- Benjamin D Towbin
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | | | | |
Collapse
|
28
|
Abstract
The substantial socioeconomic burden of a diagnosis of cerebral palsy, coupled with a positive anecdotal and media spin on stem cell treatments, drives many affected families to seek information and treatment outside of the current clinical and scientific realm. Preclinical studies using several types of stem and adult cells--including mesenchymal stem cells, neural precursor cells, olfactory ensheathing glia and Schwann cells--have demonstrated some regenerative and functional efficacy in neurologic paradigms. This paper describes the most common cell types investigated for transplant in vivo and summarizes the current state of early-phase clinical trials. It investigates the most relevant and promising coadministered therapies, including rehabilitation, drug targeting, magnetic stimulation, and bioengineering approaches. We highlight the need for adjunctive combinatorial strategies to successfully transfer stem cell treatments from bench to bedside.
Collapse
|
29
|
Papantonis A, Cook PR. Transcription factories: genome organization and gene regulation. Chem Rev 2013; 113:8683-705. [PMID: 23597155 DOI: 10.1021/cr300513p] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Argyris Papantonis
- Sir William Dunn School of Pathology, University of Oxford , South Parks Road, Oxford OX1 3RE, United Kingdom
| | | |
Collapse
|
30
|
Ho AS, Turcan S, Chan TA. Epigenetic therapy: use of agents targeting deacetylation and methylation in cancer management. Onco Targets Ther 2013; 6:223-32. [PMID: 23569385 PMCID: PMC3615839 DOI: 10.2147/ott.s34680] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The emergence of epigenetic mechanisms as key regulators of gene expression has led to dramatic advances in understanding cancer biology. Driven by complex layers that include aberrant DNA methylation and histone modification, epigenetic aberrations have emerged as critical processes that disrupt cellular machinery and homeostasis. Recent discoveries have already translated into successful clinical trials and improved patient care, with several agents approved for hematologic disease and others undergoing study. As the field matures, substantial challenges persist that will require resolution. These include the need to decipher more fully the interplay between the epigenetic and genetic machinery, patient selection and improving treatment efficacy in solid tumors, and optimizing combination therapies to counteract chemoresistance and minimize adverse effects. Here, we review recent progress in epigenetic treatments and consider their implications for future cancer therapy.
Collapse
Affiliation(s)
- Allen S Ho
- Human Oncology and Pathogenesis Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | | | | |
Collapse
|
31
|
Abstract
Immune response to pathogens depends on coordinated regulation of numerous genes that contribute collectively to pathogen elimination and restoration of the integrity of the affected tissue. The pathogen-induced gene expression is governed largely by the signal-induced posttranslational histone modifications that facilitate assembly of the functionally distinct chromatin complexes. In this review, we describe the principles of chromatin-based gene regulation during innate immune responses. We discuss the ability of pathogens to hijack the host response by interfering with various arms of transcriptional machinery involved in the responses. In particular, we discuss the phenomenon of the histone mimicry where interaction between histones and transcriptional regulators is targeted by pathogens that carry the histone-like sequences (histone mimics). We show how the principle of isotone mimicry as an efficient way to control host gene expression has been sued for the development of novel anti-inflammatory pharmacological approaches.
Collapse
|
32
|
Reddy KL, Feinberg AP. Higher order chromatin organization in cancer. Semin Cancer Biol 2012; 23:109-15. [PMID: 23266653 DOI: 10.1016/j.semcancer.2012.12.001] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 12/12/2012] [Indexed: 01/30/2023]
Abstract
In spite of our increased understanding of how genomes are dysregulated in cancer and a plethora of molecular diagnostic tools, the front line and 'gold standard' detection of cancer remains the pathologist's detection of gross changes in cellular and tissue structure, most strikingly nuclear dis-organization. In fact, for over 140 years it has been noted that nuclear morphology is often disrupted in cancer. Even today, nuclear morphology measures include nuclear size, shape, DNA content (ploidy) and 'chromatin organization'. Given the importance of nuclear shape to diagnoses of cancer phenotypes, it is surprising and frustrating that we currently lack a detailed understanding to explain these changes and how they might arise and relate to molecular events in the cell. It is an implicit hypothesis that perturbation of chromatin and epigenetic signatures may lead to alterations in nuclear structure (or vice versa) and that these perturbations lie at the heart of cancer genesis. In this review, we attempt to synthesize research leading to our current understanding on how chromatin interactions at the nuclear lamina, epigenetic modulation and gene regulation may intersect in cancer and offer a perspective on critical experiments that would help clarify how nuclear architecture may contribute to the cancerous phenotype. We also discuss the historical understanding of nuclear structure in normal cells and as a diagnostic in cancer.
Collapse
Affiliation(s)
- Karen L Reddy
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States.
| | | |
Collapse
|