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Zhang G, Li Y, Wei G. Multi-omic analysis reveals dynamic changes of three-dimensional chromatin architecture during T cell differentiation. Commun Biol 2023; 6:773. [PMID: 37488215 PMCID: PMC10366224 DOI: 10.1038/s42003-023-05141-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 07/13/2023] [Indexed: 07/26/2023] Open
Abstract
Cell differentiation results in widespread changes in transcriptional programs as well as multi-level remodeling of three-dimensional genome architecture. Nonetheless, few synthetically investigate the chromatin higher-order landscapes in different T helper (Th) cells. Using RNA-Seq, ATAC-Seq and Hi-C assays, we characterize dynamic changes in chromatin organization at different levels during Naive CD4+ T cells differentiation into T helper 17 (Th17) and T helper 1 (Th1) cells. Upon differentiation, we observe decreased short-range and increased extra-long-range chromatin interactions. Although there is no apparent global switch in the A/B compartments, Th cells display the weaker compartmentalization. A portion of topologically associated domains are rearranged. Furthermore, we identify cell-type specific enhancer-promoter loops, many of which are associated with functional genes in Th cells, such as Rorc facilitating Th17 differentiation and Hif1a responding to intracellular oxygen levels in Th1. Taken together, these results uncover the general patterns of chromatin reorganization and epigenetic landscapes of gene regulation during T helper cell differentiation.
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Affiliation(s)
- Ge Zhang
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Ying Li
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.
| | - Gang Wei
- CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200031, China.
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2
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Del Moral-Morales A, Salgado-Albarrán M, Sánchez-Pérez Y, Wenke NK, Baumbach J, Soto-Reyes E. CTCF and Its Multi-Partner Network for Chromatin Regulation. Cells 2023; 12:1357. [PMID: 37408191 DOI: 10.3390/cells12101357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 07/07/2023] Open
Abstract
Architectural proteins are essential epigenetic regulators that play a critical role in organizing chromatin and controlling gene expression. CTCF (CCCTC-binding factor) is a key architectural protein responsible for maintaining the intricate 3D structure of chromatin. Because of its multivalent properties and plasticity to bind various sequences, CTCF is similar to a Swiss knife for genome organization. Despite the importance of this protein, its mechanisms of action are not fully elucidated. It has been hypothesized that its versatility is achieved through interaction with multiple partners, forming a complex network that regulates chromatin folding within the nucleus. In this review, we delve into CTCF's interactions with other molecules involved in epigenetic processes, particularly histone and DNA demethylases, as well as several long non-coding RNAs (lncRNAs) that are able to recruit CTCF. Our review highlights the importance of CTCF partners to shed light on chromatin regulation and pave the way for future exploration of the mechanisms that enable the finely-tuned role of CTCF as a master regulator of chromatin.
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Affiliation(s)
- Aylin Del Moral-Morales
- Departamento de Ciencias Naturales, Universidad Autónoma Metropolitana-Cuajimalpa (UAM-C), Mexico City 05348, Mexico
- Institute for Computational Systems Biology, University of Hamburg, D-22607 Hamburg, Germany
| | - Marisol Salgado-Albarrán
- Departamento de Ciencias Naturales, Universidad Autónoma Metropolitana-Cuajimalpa (UAM-C), Mexico City 05348, Mexico
- Institute for Computational Systems Biology, University of Hamburg, D-22607 Hamburg, Germany
| | - Yesennia Sánchez-Pérez
- Subdirección de Investigación, Instituto Nacional de Cancerología, Mexico City 14080, Mexico
| | - Nina Kerstin Wenke
- Institute for Computational Systems Biology, University of Hamburg, D-22607 Hamburg, Germany
| | - Jan Baumbach
- Institute for Computational Systems Biology, University of Hamburg, D-22607 Hamburg, Germany
- Computational BioMedicine Lab., University of Southern Denmark, DK-5230 Odense, Denmark
| | - Ernesto Soto-Reyes
- Departamento de Ciencias Naturales, Universidad Autónoma Metropolitana-Cuajimalpa (UAM-C), Mexico City 05348, Mexico
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3
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Trangle SS, Rosenberg T, Parnas H, Levy G, Bar E, Marco A, Barak B. In individuals with Williams syndrome, dysregulation of methylation in non-coding regions of neuronal and oligodendrocyte DNA is associated with pathology and cortical development. Mol Psychiatry 2023; 28:1112-1127. [PMID: 36577841 DOI: 10.1038/s41380-022-01921-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 12/03/2022] [Accepted: 12/12/2022] [Indexed: 12/29/2022]
Abstract
Williams syndrome (WS) is a neurodevelopmental disorder caused by a heterozygous micro-deletion in the WS critical region (WSCR) and is characterized by hyper-sociability and neurocognitive abnormalities. Nonetheless, whether and to what extent WSCR deletion leads to epigenetic modifications in the brain and induces pathological outcomes remains largely unknown. By examining DNA methylation in frontal cortex, we revealed genome-wide disruption in the methylome of individuals with WS, as compared to typically developed (TD) controls. Surprisingly, differentially methylated sites were predominantly annotated as introns and intergenic loci and were found to be highly enriched around binding sites for transcription factors that regulate neuronal development, plasticity and cognition. Moreover, by utilizing enhancer-promoter interactome data, we confirmed that most of these loci function as active enhancers in the human brain or as target genes of transcriptional networks associated with myelination, oligodendrocyte (OL) differentiation, cognition and social behavior. Cell type-specific methylation analysis revealed aberrant patterns in the methylation of active enhancers in neurons and OLs, and important neuron-glia interactions that might be impaired in individuals with WS. Finally, comparison of methylation profiles from blood samples of individuals with WS and healthy controls, along with other data collected in this study, identified putative targets of endophenotypes associated with WS, which can be used to define brain-risk loci for WS outside the WSCR locus, as well as for other associated pathologies. In conclusion, our study illuminates the brain methylome landscape of individuals with WS and sheds light on how these aberrations might be involved in social behavior and physiological abnormalities. By extension, these results may lead to better diagnostics and more refined therapeutic targets for WS.
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Affiliation(s)
- Sari Schokoroy Trangle
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Tali Rosenberg
- Neuro-Epigenetics Laboratory, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Hadar Parnas
- Neuro-Epigenetics Laboratory, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Gilad Levy
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Ela Bar
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel.,The School of Neurobiology, Biochemistry & Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Asaf Marco
- Neuro-Epigenetics Laboratory, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel.
| | - Boaz Barak
- The School of Psychological Sciences, Faculty of Social Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel.
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4
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Eckardt JN, Stasik S, Röllig C, Sauer T, Scholl S, Hochhaus A, Crysandt M, Brümmendorf TH, Naumann R, Steffen B, Kunzmann V, Einsele H, Schaich M, Burchert A, Neubauer A, Schäfer-Eckart K, Schliemann C, Krause SW, Herbst R, Hänel M, Hanoun M, Kaiser U, Kaufmann M, Rácil Z, Mayer J, Cerqueira T, Kroschinsky F, Berdel WE, Serve H, Müller-Tidow C, Platzbecker U, Baldus CD, Schetelig J, Siepmann T, Bornhäuser M, Middeke JM, Thiede C. Alterations of cohesin complex genes in acute myeloid leukemia: differential co-mutations, clinical presentation and impact on outcome. Blood Cancer J 2023; 13:18. [PMID: 36693840 PMCID: PMC9873811 DOI: 10.1038/s41408-023-00790-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/25/2023] Open
Abstract
Functional perturbations of the cohesin complex with subsequent changes in chromatin structure and replication are reported in a multitude of cancers including acute myeloid leukemia (AML). Mutations of its STAG2 subunit may predict unfavorable risk as recognized by the 2022 European Leukemia Net recommendations, but the underlying evidence is limited by small sample sizes and conflicting observations regarding clinical outcomes, as well as scarce information on other cohesion complex subunits. We retrospectively analyzed data from a multi-center cohort of 1615 intensively treated AML patients and identified distinct co-mutational patters for mutations of STAG2, which were associated with normal karyotypes (NK) and concomitant mutations in IDH2, RUNX1, BCOR, ASXL1, and SRSF2. Mutated RAD21 was associated with NK, mutated EZH2, KRAS, CBL, and NPM1. Patients harboring mutated STAG2 were older and presented with decreased white blood cell, bone marrow and peripheral blood blast counts. Overall, neither mutated STAG2, RAD21, SMC1A nor SMC3 displayed any significant, independent effect on clinical outcomes defined as complete remission, event-free, relapse-free or overall survival. However, we found almost complete mutual exclusivity of genetic alterations of individual cohesin subunits. This mutual exclusivity may be the basis for therapeutic strategies via synthetic lethality in cohesin mutated AML.
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Affiliation(s)
- Jan-Niklas Eckardt
- Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany. .,Division of Health Care Sciences, Dresden International University, Dresden, Germany.
| | - Sebastian Stasik
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Christoph Röllig
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Tim Sauer
- grid.5253.10000 0001 0328 4908German Cancer Research Center (DKFZ) and Medical Clinic V, University Hospital Heidelberg, Heidelberg, Germany
| | - Sebastian Scholl
- grid.275559.90000 0000 8517 6224Department of Internal Medicine II, Jena University Hospital, Jena, Germany
| | - Andreas Hochhaus
- grid.275559.90000 0000 8517 6224Department of Internal Medicine II, Jena University Hospital, Jena, Germany
| | - Martina Crysandt
- grid.412301.50000 0000 8653 1507Department of Hematology, Oncology, Hemostaseology, and Cell Therapy, University Hospital RWTH Aachen, Aachen, Germany
| | - Tim H. Brümmendorf
- grid.412301.50000 0000 8653 1507Department of Hematology, Oncology, Hemostaseology, and Cell Therapy, University Hospital RWTH Aachen, Aachen, Germany
| | - Ralph Naumann
- Medical Clinic III, St. Marien-Hospital Siegen, Siegen, Germany
| | - Björn Steffen
- grid.411088.40000 0004 0578 8220Medical Clinic II, University Hospital Frankfurt, Frankfurt (Main), Germany
| | - Volker Kunzmann
- grid.411760.50000 0001 1378 7891Medical Clinic and Policlinic II, University Hospital Würzburg, Würzburg, Germany
| | - Hermann Einsele
- grid.411760.50000 0001 1378 7891Medical Clinic and Policlinic II, University Hospital Würzburg, Würzburg, Germany
| | - Markus Schaich
- grid.459932.0Department of Hematology, Oncology and Palliative Care, Rems-Murr-Hospital Winnenden, Winnenden, Germany
| | - Andreas Burchert
- grid.10253.350000 0004 1936 9756Department of Hematology, Oncology and Immunology, Philipps-University-Marburg, Marburg, Germany
| | - Andreas Neubauer
- grid.10253.350000 0004 1936 9756Department of Hematology, Oncology and Immunology, Philipps-University-Marburg, Marburg, Germany
| | - Kerstin Schäfer-Eckart
- grid.511981.5Department of Internal Medicine V, Paracelsus Medizinische Privatuniversität and University Hospital Nurnberg, Nurnberg, Germany
| | - Christoph Schliemann
- grid.16149.3b0000 0004 0551 4246Department of Medicine A, University Hospital Münster, Münster, Germany
| | - Stefan W. Krause
- grid.411668.c0000 0000 9935 6525Medical Clinic V, University Hospital Erlangen, Erlangen, Germany
| | - Regina Herbst
- grid.459629.50000 0004 0389 4214Medical Clinic III, Chemnitz Hospital AG, Chemnitz, Germany
| | - Mathias Hänel
- grid.459629.50000 0004 0389 4214Medical Clinic III, Chemnitz Hospital AG, Chemnitz, Germany
| | - Maher Hanoun
- grid.410718.b0000 0001 0262 7331Department of Hematology, University Hospital Essen, Essen, Germany
| | - Ulrich Kaiser
- grid.460019.aMedical Clinic II, St. Bernward Hospital, Hildesheim, Germany
| | - Martin Kaufmann
- grid.416008.b0000 0004 0603 4965Department of Hematology, Oncology and Palliative Care, Robert-Bosch-Hospital, Stuttgart, Germany
| | - Zdenek Rácil
- grid.412554.30000 0004 0609 2751Department of Internal Medicine, Hematology and Oncology, Masaryk University Hospital, Brno, Czech Republic
| | - Jiri Mayer
- grid.412554.30000 0004 0609 2751Department of Internal Medicine, Hematology and Oncology, Masaryk University Hospital, Brno, Czech Republic
| | - Tiago Cerqueira
- grid.440925.e0000 0000 9874 1261Division of Health Care Sciences, Dresden International University, Dresden, Germany
| | - Frank Kroschinsky
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Wolfgang E. Berdel
- grid.16149.3b0000 0004 0551 4246Department of Medicine A, University Hospital Münster, Münster, Germany
| | - Hubert Serve
- grid.411088.40000 0004 0578 8220Medical Clinic II, University Hospital Frankfurt, Frankfurt (Main), Germany
| | - Carsten Müller-Tidow
- grid.5253.10000 0001 0328 4908German Cancer Research Center (DKFZ) and Medical Clinic V, University Hospital Heidelberg, Heidelberg, Germany
| | - Uwe Platzbecker
- grid.411339.d0000 0000 8517 9062Medical Clinic I Hematology and Celltherapy, University Hospital Leipzig, Leipzig, Germany
| | - Claudia D. Baldus
- grid.412468.d0000 0004 0646 2097Department of Internal Medicine, University Hospital Kiel, Kiel, Germany
| | - Johannes Schetelig
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany ,DKMS Clinical Trials Unit, Dresden, Germany
| | - Timo Siepmann
- grid.440925.e0000 0000 9874 1261Division of Health Care Sciences, Dresden International University, Dresden, Germany ,grid.4488.00000 0001 2111 7257Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Martin Bornhäuser
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany ,grid.7497.d0000 0004 0492 0584German Consortium for Translational Cancer Research DKTK, Heidelberg, Germany ,National Center for Tumor Disease (NCT), Dresden, Germany
| | - Jan Moritz Middeke
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany
| | - Christian Thiede
- grid.412282.f0000 0001 1091 2917Department of Internal Medicine I, University Hospital Carl Gustav Carus, Dresden, Germany
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Saddeek S, Almassabi R, Mobashir M. Role of ZNF143 and Its Association with Gene Expression Patterns, Noncoding Mutations, and the Immune System in Human Breast Cancer. LIFE (BASEL, SWITZERLAND) 2022; 13:life13010027. [PMID: 36675976 PMCID: PMC9865137 DOI: 10.3390/life13010027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/10/2022] [Accepted: 12/16/2022] [Indexed: 12/25/2022]
Abstract
The function of noncoding sequence variations at ZNF143 binding sites in breast cancer cells is currently not well understood. Distal elements and promoters, also known as cis-regulatory elements, control the expression of genes. They may be identified by functional genomic techniques and sequence conservation, and they frequently show cell- and tissue-type specificity. The creation, destruction, or modulation of TF binding and function may be influenced by genetic modifications at TF binding sites that affect the binding affinity. Therefore, noncoding mutations that affect the ZNF143 binding site may be able to alter the expression of some genes in breast cancer. In order to understand the relationship among ZNF143, gene expression patterns, and noncoding mutations, we adopted an integrative strategy in this study and paid close attention to putative immunological signaling pathways. The immune system-related pathways ErbB, HIF1a, NF-kB, FoxO, JAK-STAT, Wnt, Notch, cell cycle, PI3K-AKT, RAP1, calcium signaling, cell junctions and adhesion, actin cytoskeleton regulation, and cancer pathways are among those that may be significant, according to the overall analysis.
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Affiliation(s)
- Salma Saddeek
- Department of Chemistry, Faculty of Sciences, Universty of Hafr Al Batin, Hafr Al Batin 39524, Saudi Arabia
| | - Rehab Almassabi
- Department of Biochemistry, Faculty of Sciences, University of Tabuk, Tabuk 47512, Saudi Arabia
| | - Mohammad Mobashir
- SciLifeLab, Department of Oncology and Pathology, Karolinska Institutet, P.O. Box 1031, 17121 Stockholm, Sweden
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solnavägen 9, 17165 Solna, Sweden
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Centre, King Abdulaziz University, Jeddah 21362, Saudi Arabia
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6
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Zhang Y, Tian GG, Wang X, Hou C, Hu X, Wu J. Retinoic acid induced meiosis initiation in female germline stem cells by remodelling three-dimensional chromatin structure. Cell Prolif 2022; 55:e13242. [PMID: 35633286 PMCID: PMC9251051 DOI: 10.1111/cpr.13242] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 04/08/2022] [Accepted: 04/13/2022] [Indexed: 12/11/2022] Open
Abstract
Objectives This study aimed to clarify the regulation and mechanism of meiotic initiation in FGSC development. Materials and Methods FGSCs were induced to differentiate into meiosis in differentiation medium. RNA sequencing was performed to analysis the difference of transcription level. High‐through chromosome conformation capture sequencing (Hi‐C) was performed to analysis changes of three‐dimensional chromatin structure. Chromosome conformation capture further confirmed a spatial chromatin loop. ChIP‐qPCR and dual luciferase reporter were used to test the interaction between Stimulated by retinoic acid gene 8 (STRA8) protein and Trip13 promoter. Results Compared with FGSCs, the average diameter of STRA8‐positive germ cells increased from 13 μm to 16.8 μm. Furthermore, there were 4788 differentially expressed genes between the two cell stages; Meiosis and chromatin structure‐associated terms were significantly enriched. Additionally, Hi‐C results showed that FGSCs underwent A/B compartment switching (switch rate was 29.81%), the number of topologically associating domains (TADs) increasing, the average size of TADs decreasing, and chromatin loop changes at genome region of Trip13 from undifferentiated stage to meiosis‐initiation stage. Furthermore, we validated that Trip13 promoter contacted distal enhancer to form spatial chromatin loop and STRA8 could bind Trip13 promoter to promote gene expression. Conclusion FGSCs underwent chromatin structure remodelling from undifferentiated stage to meiosis‐initiation stage, which facilitated STRA8 binding to Trip13 promoter and promoting its expression.
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Affiliation(s)
- Yabin Zhang
- Key Laboratory for the Genetics of Developmental & Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - Geng G Tian
- Key Laboratory for the Genetics of Developmental & Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - Xiang Wang
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan, China
| | - Changliang Hou
- Key Laboratory for the Genetics of Developmental & Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaopeng Hu
- Key Laboratory for the Genetics of Developmental & Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China
| | - Ji Wu
- Key Laboratory for the Genetics of Developmental & Neuropsychiatric Disorders (Ministry of Education), Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, China.,Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan, China
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7
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Xu W, Yan Y, Artsimovitch I, Dunlap D, Finzi L. Positive supercoiling favors transcription elongation through lac repressor-mediated DNA loops. Nucleic Acids Res 2022; 50:2826-2835. [PMID: 35188572 PMCID: PMC8934669 DOI: 10.1093/nar/gkac093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/22/2021] [Accepted: 02/20/2022] [Indexed: 11/30/2022] Open
Abstract
Some proteins, like the lac repressor (LacI), mediate long-range loops that alter DNA topology and create torsional barriers. During transcription, RNA polymerase generates supercoiling that may facilitate passage through such barriers. We monitored E. coli RNA polymerase progress along templates in conditions that prevented, or favored, 400 bp LacI-mediated DNA looping. Tethered particle motion measurements revealed that RNA polymerase paused longer at unlooped LacI obstacles or those barring entry to a loop than those barring exit from the loop. Enhanced dissociation of a LacI roadblock by the positive supercoiling generated ahead of a transcribing RNA polymerase within a torsion-constrained DNA loop may be responsible for this reduction in pause time. In support of this idea, RNA polymerase transcribed 6-fold more slowly through looped DNA and paused at LacI obstacles for 66% less time on positively supercoiled compared to relaxed templates, especially under increased tension (torque). Positive supercoiling propagating ahead of polymerase facilitated elongation along topologically complex, protein-coated templates.
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Affiliation(s)
- Wenxuan Xu
- Physics Department, Emory University, Atlanta, GA, USA
| | - Yan Yan
- Physics Department, Emory University, Atlanta, GA, USA
| | | | - David Dunlap
- Physics Department, Emory University, Atlanta, GA, USA
| | - Laura Finzi
- Physics Department, Emory University, Atlanta, GA, USA
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8
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Alharbi AB, Schmitz U, Bailey CG, Rasko JEJ. CTCF as a regulator of alternative splicing: new tricks for an old player. Nucleic Acids Res 2021; 49:7825-7838. [PMID: 34181707 PMCID: PMC8373115 DOI: 10.1093/nar/gkab520] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 06/01/2021] [Accepted: 06/10/2021] [Indexed: 12/15/2022] Open
Abstract
Three decades of research have established the CCCTC-binding factor (CTCF) as a ubiquitously expressed chromatin organizing factor and master regulator of gene expression. A new role for CTCF as a regulator of alternative splicing (AS) has now emerged. CTCF has been directly and indirectly linked to the modulation of AS at the individual transcript and at the transcriptome-wide level. The emerging role of CTCF-mediated regulation of AS involves diverse mechanisms; including transcriptional elongation, DNA methylation, chromatin architecture, histone modifications, and regulation of splicing factor expression and assembly. CTCF thereby appears to not only co-ordinate gene expression regulation but contributes to the modulation of transcriptomic complexity. In this review, we highlight previous discoveries regarding the role of CTCF in AS. In addition, we summarize detailed mechanisms by which CTCF mediates AS regulation. We propose opportunities for further research designed to examine the possible fate of CTCF-mediated alternatively spliced genes and associated biological consequences. CTCF has been widely acknowledged as the 'master weaver of the genome'. Given its multiple connections, further characterization of CTCF's emerging role in splicing regulation might extend its functional repertoire towards a 'conductor of the splicing orchestra'.
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Affiliation(s)
- Adel B Alharbi
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Department of Laboratory Medicine, Faculty of Applied Medical Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
- Cancer & Gene Regulation Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
| | - Ulf Schmitz
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Computational BioMedicine Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
| | - Charles G Bailey
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
- Cancer & Gene Regulation Laboratory Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
| | - John E J Rasko
- Gene & Stem Cell Therapy Program Centenary Institute, The University of Sydney, Camperdown, NSW 2050, Australia
- Faculty of Medicine & Health, The University of Sydney, NSW 2006, Australia
- Cell & Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
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9
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Tiwari V, Kulikowicz T, Wilson DM, Bohr VA. LEO1 is a partner for Cockayne syndrome protein B (CSB) in response to transcription-blocking DNA damage. Nucleic Acids Res 2021; 49:6331-6346. [PMID: 34096589 DOI: 10.1093/nar/gkab458] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/04/2021] [Accepted: 06/03/2021] [Indexed: 12/25/2022] Open
Abstract
Cockayne syndrome (CS) is an autosomal recessive genetic disorder characterized by photosensitivity, developmental defects, neurological abnormalities, and premature aging. Mutations in CSA (ERCC8), CSB (ERCC6), XPB, XPD, XPG, XPF (ERCC4) and ERCC1 can give rise to clinical phenotypes resembling classic CS. Using a yeast two-hybrid (Y2H) screening approach, we identified LEO1 (Phe381-Ser568 region) as an interacting protein partner of full-length and C-terminal (Pro1010-Cys1493) CSB in two independent screens. LEO1 is a member of the RNA polymerase associated factor 1 complex (PAF1C) with roles in transcription elongation and chromatin modification. Supportive of the Y2H results, purified, recombinant LEO1 and CSB directly interact in vitro, and the two proteins exist in a common complex within human cells. In addition, fluorescently tagged LEO1 and CSB are both recruited to localized DNA damage sites in human cells. Cell fractionation experiments revealed a transcription-dependent, coordinated association of LEO1 and CSB to chromatin following either UVC irradiation or cisplatin treatment of HEK293T cells, whereas the response to menadione was distinct, suggesting that this collaboration occurs mainly in the context of bulky transcription-blocking lesions. Consistent with a coordinated interaction in DNA repair, LEO1 knockdown or knockout resulted in reduced CSB recruitment to chromatin, increased sensitivity to UVC light and cisplatin damage, and reduced RNA synthesis recovery and slower excision of cyclobutane pyrimidine dimers following UVC irradiation; the absence of CSB resulted in diminished LEO1 recruitment. Our data indicate a reciprocal communication between CSB and LEO1 in the context of transcription-associated DNA repair and RNA transcription recovery.
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Affiliation(s)
- Vinod Tiwari
- Section on DNA repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Tomasz Kulikowicz
- Section on DNA repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - David M Wilson
- Hasselt University, Biomedical Research Institute, 3590 Diepenbeek, Belgium
| | - Vilhelm A Bohr
- Section on DNA repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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Davenport KM, Massa AT, Bhattarai S, McKay SD, Mousel MR, Herndon MK, White SN, Cockett NE, Smith TPL, Murdoch BM. Characterizing Genetic Regulatory Elements in Ovine Tissues. Front Genet 2021; 12:628849. [PMID: 34093640 PMCID: PMC8173140 DOI: 10.3389/fgene.2021.628849] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/25/2021] [Indexed: 12/11/2022] Open
Abstract
The Ovine Functional Annotation of Animal Genomes (FAANG) project, part of the broader livestock species FAANG initiative, aims to identify and characterize gene regulatory elements in domestic sheep. Regulatory element annotation is essential for identifying genetic variants that affect health and production traits in this important agricultural species, as greater than 90% of variants underlying genetic effects are estimated to lie outside of transcribed regions. Histone modifications that distinguish active or repressed chromatin states, CTCF binding, and DNA methylation were used to characterize regulatory elements in liver, spleen, and cerebellum tissues from four yearling sheep. Chromatin immunoprecipitation with sequencing (ChIP-seq) was performed for H3K4me3, H3K27ac, H3K4me1, H3K27me3, and CTCF. Nine chromatin states including active promoters, active enhancers, poised enhancers, repressed enhancers, and insulators were characterized in each tissue using ChromHMM. Whole-genome bisulfite sequencing (WGBS) was performed to determine the complement of whole-genome DNA methylation with the ChIP-seq data. Hypermethylated and hypomethylated regions were identified across tissues, and these locations were compared with chromatin states to better distinguish and validate regulatory elements in these tissues. Interestingly, chromatin states with the poised enhancer mark H3K4me1 in the spleen and cerebellum and CTCF in the liver displayed the greatest number of hypermethylated sites. Not surprisingly, active enhancers in the liver and spleen, and promoters in the cerebellum, displayed the greatest number of hypomethylated sites. Overall, chromatin states defined by histone marks and CTCF occupied approximately 22% of the genome in all three tissues. Furthermore, the liver and spleen displayed in common the greatest percent of active promoter (65%) and active enhancer (81%) states, and the liver and cerebellum displayed in common the greatest percent of poised enhancer (53%), repressed enhancer (68%), hypermethylated sites (75%), and hypomethylated sites (73%). In addition, both known and de novo CTCF-binding motifs were identified in all three tissues, with the highest number of unique motifs identified in the cerebellum. In summary, this study has identified the regulatory regions of genes in three tissues that play key roles in defining health and economically important traits and has set the precedent for the characterization of regulatory elements in ovine tissues using the Rambouillet reference genome.
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Affiliation(s)
- Kimberly M. Davenport
- Department of Animal, Veterinary, and Food Science, University of Idaho, Moscow, ID, United States
| | - Alisha T. Massa
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
| | | | | | - Michelle R. Mousel
- USDA, ARS, Animal Disease Research Unit, Pullman, WA, United States
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, United States
| | - Maria K. Herndon
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
| | - Stephen N. White
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, United States
- USDA, ARS, Animal Disease Research Unit, Pullman, WA, United States
- Center for Reproductive Biology, Washington State University, Pullman, WA, United States
| | | | - Timothy P. L. Smith
- USDA, ARS, U.S. Meat Animal Research Center (USMARC), Clay Center, NE, United States
| | - Brenda M. Murdoch
- Department of Animal, Veterinary, and Food Science, University of Idaho, Moscow, ID, United States
- Center for Reproductive Biology, Washington State University, Pullman, WA, United States
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11
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Han C, Gao X, Li Y, Zhang J, Yang E, Zhang L, Yu L. Characteristics of Cohesin Mutation in Acute Myeloid Leukemia and Its Clinical Significance. Front Oncol 2021; 11:579881. [PMID: 33928020 PMCID: PMC8076553 DOI: 10.3389/fonc.2021.579881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 03/18/2021] [Indexed: 12/18/2022] Open
Abstract
The occurrence of gene mutation is a major contributor to the initiation and propagation of acute myeloid leukemia (AML). Accumulating evidence suggests that genes encoding cohesin subunits have a high prevalence of mutations in AML, especially in the t(8;21) subtype. Therefore, it is important to understand how cohesin mutations contribute to leukemogenesis. However, the fundamental understanding of cohesin mutation in clonal expansion and myeloid transformation in hematopoietic cells remains ambiguous. Previous studies briefly introduced the cohesin mutation in AML; however, an in-depth summary of mutations in AML was not provided, and the correlation between cohesin and AML1-ETO in t (8;21) AML was also not analyzed. By summarizing the major findings regarding the cohesin mutation in AML, this review aims to define the characteristics of the cohesin complex mutation, identify its relationships with co-occurring gene mutations, assess its roles in clonal evolution, and discuss its potential for the prognosis of AML. In particular, we focus on the function of cohesin mutations in RUNX1-RUNX1T1 fusion.
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Affiliation(s)
- Caixia Han
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
| | - Xuefeng Gao
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
| | - Yonghui Li
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
| | - Juan Zhang
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
| | - Erna Yang
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
| | - Li Zhang
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
| | - Li Yu
- Department of Hematology and Oncology, International Cancer Center, Shenzhen Key Laboratory of Precision Medicine for Hematological Malignancies, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University Health Science Center, Shenzhen, China
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12
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Tiwari V, Baptiste BA, Okur MN, Bohr VA. Current and emerging roles of Cockayne syndrome group B (CSB) protein. Nucleic Acids Res 2021; 49:2418-2434. [PMID: 33590097 DOI: 10.1093/nar/gkab085] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/11/2022] Open
Abstract
Cockayne syndrome (CS) is a segmental premature aging syndrome caused primarily by defects in the CSA or CSB genes. In addition to premature aging, CS patients typically exhibit microcephaly, progressive mental and sensorial retardation and cutaneous photosensitivity. Defects in the CSB gene were initially thought to primarily impair transcription-coupled nucleotide excision repair (TC-NER), predicting a relatively consistent phenotype among CS patients. In contrast, the phenotypes of CS patients are pleiotropic and variable. The latter is consistent with recent work that implicates CSB in multiple cellular systems and pathways, including DNA base excision repair, interstrand cross-link repair, transcription, chromatin remodeling, RNAPII processing, nucleolin regulation, rDNA transcription, redox homeostasis, and mitochondrial function. The discovery of additional functions for CSB could potentially explain the many clinical phenotypes of CSB patients. This review focuses on the diverse roles played by CSB in cellular pathways that enhance genome stability, providing insight into the molecular features of this complex premature aging disease.
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Affiliation(s)
- Vinod Tiwari
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Beverly A Baptiste
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Mustafa N Okur
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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13
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Abstract
Mutations of the cohesin complex in human cancer were first discovered ~10 years ago. Since then, researchers worldwide have demonstrated that cohesin is among the most commonly mutated protein complexes in cancer. Inactivating mutations in genes encoding cohesin subunits are common in bladder cancers, paediatric sarcomas, leukaemias, brain tumours and other cancer types. Also in those 10 years, the prevailing view of the functions of cohesin in cell biology has undergone a revolutionary transformation. Initially, the predominant view of cohesin was as a ring that encircled and cohered replicated chromosomes until its cleavage triggered the metaphase-to-anaphase transition. As such, early studies focused on the role of tumour-derived cohesin mutations in the fidelity of chromosome segregation and aneuploidy. However, over the past 5 years the cohesin field has shifted dramatically, and research now focuses on the primary role of cohesin in generating, maintaining and regulating the intra-chromosomal DNA looping events that modulate 3D genome organization and gene expression. This Review focuses on recent discoveries in the cohesin field that provide insight into the role of cohesin inactivation in cancer pathogenesis, and opportunities for exploiting these findings for the clinical benefit of patients with cohesin-mutant cancers.
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Affiliation(s)
- Todd Waldman
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University School of Medicine, Washington, DC, USA.
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14
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Li F, Wang D, Song R, Cao C, Zhang Z, Wang Y, Li X, Huang J, Liu Q, Hou N, Xu B, Li X, Gao X, Jia Y, Zhao J, Wang Y. The asynchronous establishment of chromatin 3D architecture between in vitro fertilized and uniparental preimplantation pig embryos. Genome Biol 2020; 21:203. [PMID: 32778155 PMCID: PMC7418210 DOI: 10.1186/s13059-020-02095-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Pigs are important animals for agricultural and biomedical research, and improvement is needed for use of the assisted reproductive technologies. Determining underlying mechanisms of epigenetic reprogramming in the early stage of preimplantation embryos derived from in vitro fertilization (IVF), parthenogenesis, and androgenesis will not only contribute to assisted reproductive technologies of pigs but also will shed light into early human development. However, the reprogramming of three-dimensional architecture of chromatin in this process in pigs is poorly understood. RESULTS We generate three-dimensional chromatin profiles for pig somatic cells, IVF, parthenogenesis, and androgenesis preimplantation embryos. We find that the chromosomes in the pig preimplantation embryos are enriched for superdomains, which are more rare in mice. However, p(s) curves, compartments, and topologically associated domains (TADs) are largely conserved in somatic cells and are gradually established during preimplantation embryogenesis in both mammals. In the uniparental pig embryos, the establishment of chromatin architecture is highly asynchronized at all levels from IVF embryos, and a remarkably strong decompartmentalization is observed during zygotic genome activation (ZGA). Finally, chromosomes originating from oocytes always establish TADs faster than chromosomes originating from sperm, both before and during ZGA. CONCLUSIONS Our data highlight a potential unique 3D chromatin pattern of enriched superdomains in pig preimplantation embryos, an unusual decompartmentalization process during ZGA in the uniparental embryos, and an asynchronized TAD reprogramming between maternal and paternal genomes, implying a severe dysregulation of ZGA in the uniparental embryos in pigs.
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Affiliation(s)
- Feifei Li
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
| | - Danyang Wang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Ruigao Song
- University of Chinese Academy of Sciences, Beijing, 100049 China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Chunwei Cao
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120 China
| | - Zhihua Zhang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yu Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Xiaoli Li
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jiaojiao Huang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qiang Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Naipeng Hou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
| | - Bingxiang Xu
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xiao Li
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xiaomeng Gao
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yan Jia
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, and China National Center for Bioinformation, Beijing, 100101 China
| | - Jianguo Zhao
- University of Chinese Academy of Sciences, Beijing, 100049 China
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Yanfang Wang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 China
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15
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Reina C, Cavalieri V. Epigenetic Modulation of Chromatin States and Gene Expression by G-Quadruplex Structures. Int J Mol Sci 2020; 21:E4172. [PMID: 32545267 PMCID: PMC7312119 DOI: 10.3390/ijms21114172] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/07/2020] [Accepted: 06/10/2020] [Indexed: 02/07/2023] Open
Abstract
G-quadruplexes are four-stranded helical nucleic acid structures formed by guanine-rich sequences. A considerable number of studies have revealed that these noncanonical structural motifs are widespread throughout the genome and transcriptome of numerous organisms, including humans. In particular, G-quadruplexes occupy strategic locations in genomic DNA and both coding and noncoding RNA molecules, being involved in many essential cellular and organismal functions. In this review, we first outline the fundamental structural features of G-quadruplexes and then focus on the concept that these DNA and RNA structures convey a distinctive layer of epigenetic information that is critical for the complex regulation, either positive or negative, of biological activities in different contexts. In this framework, we summarize and discuss the proposed mechanisms underlying the functions of G-quadruplexes and their interacting factors. Furthermore, we give special emphasis to the interplay between G-quadruplex formation/disruption and other epigenetic marks, including biochemical modifications of DNA bases and histones, nucleosome positioning, and three-dimensional organization of chromatin. Finally, epigenetic roles of RNA G-quadruplexes in post-transcriptional regulation of gene expression are also discussed. Undoubtedly, the issues addressed in this review take on particular importance in the field of comparative epigenetics, as well as in translational research.
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Affiliation(s)
- Chiara Reina
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, 90127 Palermo, Italy;
| | - Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy
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16
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Wu E, Vastenhouw NL. From mother to embryo: A molecular perspective on zygotic genome activation. Curr Top Dev Biol 2020; 140:209-254. [PMID: 32591075 DOI: 10.1016/bs.ctdb.2020.02.002] [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] [Indexed: 12/23/2022]
Abstract
In animals, the early embryo is mostly transcriptionally silent and development is fueled by maternally supplied mRNAs and proteins. These maternal products are important not only for survival, but also to gear up the zygote's genome for activation. Over the last three decades, research with different model organisms and experimental approaches has identified molecular factors and proposed mechanisms for how the embryo transitions from being transcriptionally silent to transcriptionally competent. In this chapter, we discuss the molecular players that shape the molecular landscape of ZGA and provide insights into their mode of action in activating the transcription program in the developing embryo.
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Affiliation(s)
- Edlyn Wu
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Nadine L Vastenhouw
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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17
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In silico analysis of human renin gene-gene interactions and neighborhood topologically associated domains suggests breakdown of insulators contribute to ageing-associated diseases. Biogerontology 2019; 20:857-869. [PMID: 31520345 DOI: 10.1007/s10522-019-09834-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/09/2019] [Indexed: 12/28/2022]
Abstract
Three-dimensional chromatin architecture and gene-gene interactions impact gene expression. We assembled this information, in silico, for the human renin gene (REN). We searched for chromatin contacts and boundaries and the locations of super-enhancers that are involved in cell specific differentiation. The REN promoter was connected via RNA polymerase II binding to promoters of 12 neighboring genes on chromosome 1q32.1 over a distance of 762,497 bp. This constitutes a regulatory archipelago. The genes formed 3 topologically associated domains (TADs), as follows: TAD1: ZC3H11A, SNRPE, LINC00303; SOX13; TAD2: ETNK2, REN, KISS1, GOLT1A; TAD3: PLEKHA6, LINC00628, PPP1R15B, PIK3C2B, MDM4. REN in TAD2, was isolated from its neighboring genes in TAD1 and TAD3 by CTCF-binding sites that serve as insulators. TAD1 and TAD3 genes SOX13 and LINC00628 overlapped super-enhancers, known to reside near nodes regulating cell identity, and were co-expressed in various tissues, suggesting co-regulation. REN was also connected with 62 distant genes genome-wide, including the angiotensin II type 1 receptor gene. The findings lead us to invoke the following novel hypothesis. While the REN promoter is isolated from neighboring super-enhancers in most cells by insulators, these insulators break down with cell age to permit the inappropriate expression of REN in non-kidney cells by using the neighboring super-enhancers, resulting in expression in a wider spectrum of tissues, contributing to aging-related immune system dysregulation, cardiovascular diseases and cancers. Research is needed to confirm this hypothesis experimentally.
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18
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Liang J, Liu H, Li G, Qian J, Gao R, Zhou Y, Wang X. Global changes in chromatin accessibility and transcription following ATRX inactivation in human cancer cells. FEBS Lett 2019; 594:67-78. [PMID: 31329278 DOI: 10.1002/1873-3468.13549] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 07/13/2019] [Accepted: 07/18/2019] [Indexed: 12/22/2022]
Abstract
α-Tthalassemia mental retardation X-linked (ATRX) is a chromatin remodeler frequently mutated in many cancers. Despite the binding pattern of ATRX in heterochromatin, ATRX-mediated epigenomic changes in cancer cells have not been profiled, especially for the heterochromatin regions. Here, we profiled genome-wide maps of chromatin accessibility in ATRX-intact and ATRX-null human cancer cells. We found extensive changes in chromatin accessibility in both repetitive DNA regions and non-repetitive regulatory regions following ATRX loss. These changes are highly correlated with changes in transcription, which lead to alterations in cancer-related signalling pathways, such as upregulation of the TGF-β pathway and downregulation of the cadherin family of proteins. These findings indicate that ATRX deficiency induces epigenomic changes and promotes tumorigenesis through both genome instability and shifts in transcription.
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Affiliation(s)
- Junbo Liang
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Hongchao Liu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Guangyu Li
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Jun Qian
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Ran Gao
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Yanchi Zhou
- National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
| | - Xiaoyue Wang
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
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19
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Beck S, Rhee C, Song J, Lee BK, LeBlanc L, Cannon L, Kim J. Implications of CpG islands on chromosomal architectures and modes of global gene regulation. Nucleic Acids Res 2019. [PMID: 29529258 PMCID: PMC5961348 DOI: 10.1093/nar/gky147] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
CpG islands (CGIs) have long been implicated in the regulation of vertebrate gene expression. However, the involvement of CGIs in chromosomal architectures and associated gene expression regulations has not yet been thoroughly explored. By combining large-scale integrative data analyses and experimental validations, we show that CGIs clearly reconcile two competing models explaining nuclear gene localizations. We first identify CGI-containing (CGI+) and CGI-less (CGI-) genes are non-randomly clustered within the genome, which reflects CGI-dependent spatial gene segregation in the nucleus and corresponding gene regulatory modes. Regardless of their transcriptional activities, CGI+ genes are mainly located at the nuclear center and encounter frequent long-range chromosomal interactions. Meanwhile, nuclear peripheral CGI- genes forming heterochromatin are activated and internalized into the nuclear center by local enhancer-promoter interactions. Our findings demonstrate the crucial implications of CGIs on chromosomal architectures and gene positioning, linking the critical importance of CGIs in determining distinct mechanisms of global gene regulation in three-dimensional space in the nucleus.
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Affiliation(s)
- Samuel Beck
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Kathryn W. Davis Center for Regenerative Biology and Medicine, MDI Biological Laboratory, Bar Harbor, Maine 04609, USA
| | - Catherine Rhee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jawon Song
- Texas Advanced Computing Center, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Bum-Kyu Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Lucy LeBlanc
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Laurie Cannon
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Jonghwan Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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20
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Boetefuer EL, Lake RJ, Fan HY. Mechanistic insights into the regulation of transcription and transcription-coupled DNA repair by Cockayne syndrome protein B. Nucleic Acids Res 2019; 46:7471-7479. [PMID: 30032309 PMCID: PMC6125617 DOI: 10.1093/nar/gky660] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/10/2018] [Indexed: 12/24/2022] Open
Abstract
Cockayne syndrome protein B (CSB) is a member of the SNF2/SWI2 ATPase family and is essential for transcription-coupled nucleotide excision DNA repair (TC-NER). CSB also plays critical roles in transcription regulation. CSB can hydrolyze ATP in a DNA-dependent manner, alter protein-DNA contacts and anneal DNA strands. How the different biochemical activities of CSB are utilized in these cellular processes have only begun to become clear in recent years. Mutations in the gene encoding CSB account for majority of the Cockayne syndrome cases, which result in extreme sun sensitivity, premature aging features and/or abnormalities in neurology and development. Here, we summarize and integrate recent biochemical, structural, single-molecule and somatic cell genetic studies that have advanced our understanding of CSB. First, we review studies on the mechanisms that regulate the different biochemical activities of CSB. Next, we summarize how CSB is targeted to regulate transcription under different growth conditions. We then discuss recent advances in our understanding of how CSB regulates transcription mechanistically. Lastly, we summarize the various roles that CSB plays in the different steps of TC-NER, integrating the results of different studies and proposing a model as to how CSB facilitates TC-NER.
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Affiliation(s)
- Erica L Boetefuer
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert J Lake
- Department of Internal Medicine, Division of Molecular Medicine, Program in Cancer Genetics, Epigenetics and Genomics, University of New Mexico Comprehensive Cancer Center, Albuquerque, NM 87131, USA
| | - Hua-Ying Fan
- Department of Internal Medicine, Division of Molecular Medicine, Program in Cancer Genetics, Epigenetics and Genomics, University of New Mexico Comprehensive Cancer Center, Albuquerque, NM 87131, USA
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21
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Zehnder T, Benner P, Vingron M. Predicting enhancers in mammalian genomes using supervised hidden Markov models. BMC Bioinformatics 2019; 20:157. [PMID: 30917778 PMCID: PMC6437899 DOI: 10.1186/s12859-019-2708-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/27/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Eukaryotic gene regulation is a complex process comprising the dynamic interaction of enhancers and promoters in order to activate gene expression. In recent years, research in regulatory genomics has contributed to a better understanding of the characteristics of promoter elements and for most sequenced model organism genomes there exist comprehensive and reliable promoter annotations. For enhancers, however, a reliable description of their characteristics and location has so far proven to be elusive. With the development of high-throughput methods such as ChIP-seq, large amounts of data about epigenetic conditions have become available, and many existing methods use the information on chromatin accessibility or histone modifications to train classifiers in order to segment the genome into functional groups such as enhancers and promoters. However, these methods often do not consider prior biological knowledge about enhancers such as their diverse lengths or molecular structure. RESULTS We developed enhancer HMM (eHMM), a supervised hidden Markov model designed to learn the molecular structure of promoters and enhancers. Both consist of a central stretch of accessible DNA flanked by nucleosomes with distinct histone modification patterns. We evaluated the performance of eHMM within and across cell types and developmental stages and found that eHMM successfully predicts enhancers with high precision and recall comparable to state-of-the-art methods, and consistently outperforms those in terms of accuracy and resolution. CONCLUSIONS eHMM predicts active enhancers based on data from chromatin accessibility assays and a minimal set of histone modification ChIP-seq experiments. In comparison to other 'black box' methods its parameters are easy to interpret. eHMM can be used as a stand-alone tool for enhancer prediction without the need for additional training or a tuning of parameters. The high spatial precision of enhancer predictions gives valuable targets for potential knockout experiments or downstream analyses such as motif search.
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Affiliation(s)
- Tobias Zehnder
- Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, Berlin, 14195 Germany
| | - Philipp Benner
- Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, Berlin, 14195 Germany
| | - Martin Vingron
- Max Planck Institute for Molecular Genetics, Ihnestraße 63-73, Berlin, 14195 Germany
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22
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Perez S, Gevor M, Davidovich A, Kaspi A, Yamin K, Domovich T, Meirson T, Matityahu A, Brody Y, Stemmer SM, El-Osta A, Haviv I, Onn I, Gal-Tanamy M. Dysregulation of the cohesin subunit RAD21 by Hepatitis C virus mediates host-virus interactions. Nucleic Acids Res 2019; 47:2455-2471. [PMID: 30698808 PMCID: PMC6412124 DOI: 10.1093/nar/gkz052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 12/30/2018] [Accepted: 01/24/2019] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) infection is the leading cause of chronic hepatitis, which often results in liver fibrosis, cirrhosis and hepatocellular carcinoma (HCC). HCV possesses an RNA genome and its replication is confined to the cytoplasm. Yet, infection with HCV leads to global changes in gene expression, and chromosomal instability (CIN) in the host cell. The mechanisms by which the cytoplasmic virus affects these nuclear processes are elusive. Here, we show that HCV modulates the function of the Structural Maintenance of Chromosome (SMC) protein complex, cohesin, which tethers remote regions of chromatin. We demonstrate that infection of hepatoma cells with HCV leads to up regulation of the expression of the RAD21 cohesin subunit and changes cohesin residency on the chromatin. These changes regulate the expression of genes associated with virus-induced pathways. Furthermore, siRNA downregulation of viral-induced RAD21 reduces HCV infection. During mitosis, HCV infection induces hypercondensation of chromosomes and the appearance of multi-centrosomes. We provide evidence that the underlying mechanism involves the viral NS3/4 protease and the cohesin regulator, WAPL. Altogether, our results provide the first evidence that HCV induces changes in gene expression and chromosome structure of infected cells by modulating cohesin.
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Affiliation(s)
- Shira Perez
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
- Cancer Personalized Medicine and Diagnostic Genomics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Michael Gevor
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ateret Davidovich
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Antony Kaspi
- Epigenetics in Human Health and Disease Laboratory, Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia
| | - Katreena Yamin
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Tom Domovich
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Tomer Meirson
- Cell Migration and Invasion Laboratory, Azrieli Faculty of Medicine in the Galilee, Bar-Ilan University, Safed, Israel
| | - Avi Matityahu
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Yehuda Brody
- The Broad institute of Harvard and MIT, Cambridge, MA, USA
| | - Salomon M Stemmer
- Davidoff Center, Rabin Medical Center, Beilinson Campus, Petach Tikva, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Assam El-Osta
- Epigenetics in Human Health and Disease Laboratory, Department of Diabetes, Central Clinical School, Monash University, Melbourne, Australia
- Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR
| | - Izhak Haviv
- Cancer Personalized Medicine and Diagnostic Genomics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Meital Gal-Tanamy
- Molecular Virology Lab, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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23
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Davis L, Onn I, Elliott E. The emerging roles for the chromatin structure regulators CTCF and cohesin in neurodevelopment and behavior. Cell Mol Life Sci 2018; 75:1205-1214. [PMID: 29110030 PMCID: PMC11105208 DOI: 10.1007/s00018-017-2706-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 10/09/2017] [Accepted: 10/31/2017] [Indexed: 12/19/2022]
Abstract
Recent genetic and technological advances have determined a role for chromatin structure in neurodevelopment. In particular, compounding evidence has established roles for CTCF and cohesin, two elements that are central in the establishment of chromatin structure, in proper neurodevelopment and in regulation of behavior. Genetic aberrations in CTCF, and in subunits of the cohesin complex, have been associated with neurodevelopmental disorders in human genetic studies, and subsequent animal studies have established definitive, although sometime opposing roles, for these factors in neurodevelopment and behavior. Considering the centrality of these factors in cellular processes in general, the mechanisms through which dysregulation of CTCF and cohesin leads specifically to neurological phenotypes is intriguing, although poorly understood. The connection between CTCF, cohesin, chromatin structure, and behavior is likely to be one of the next frontiers in our understanding of the development of behavior in general, and neurodevelopmental disorders in particular.
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Affiliation(s)
- Liron Davis
- Molecular and Behavioral Neurosciences Laboratory, Faculty of Medicine in the Galilee, Bar-Ilan University, Hanrietta Sold 8, 1311502, Safed, Israel
| | - Itay Onn
- Chromosome Instability and Dynamics Laboratory, Faculty of Medicine in the Galilee, Bar-Ilan University, 1311502, Safed, Israel
| | - Evan Elliott
- Molecular and Behavioral Neurosciences Laboratory, Faculty of Medicine in the Galilee, Bar-Ilan University, Hanrietta Sold 8, 1311502, Safed, Israel.
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24
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Tang X, Srivastava A, Liu H, Machiraju R, Huang K, Leone G. annoPeak: a web application to annotate and visualize peaks from ChIP-seq/ChIP-exo-seq. Bioinformatics 2018; 33:1570-1571. [PMID: 28169395 DOI: 10.1093/bioinformatics/btx016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 01/27/2017] [Indexed: 11/12/2022] Open
Abstract
Summary We developed annoPeak, a web application to annotate, visualize and compare predicted protein-binding regions derived from ChIP-seq/ChIP-exo-seq experiments using human and mouse cells. Users can upload peak regions from multiple experiments onto the annoPeak server to annotate them with biological context, identify associated target genes and categorize binding sites with respect to gene structure. Users can also compare multiple binding profiles intuitively with the help of visualization tools and tables provided by annoPeak. In general, annoPeak will help users identify patterns of genome wide transcription factor binding profiles, assess binding profiles in different biological contexts and generate new hypotheses. Availability and Implementation The web service is freely accessible through URL: http://ccc-annopeak.osumc.edu/annoPeak . Source code is available at https://github.com/XingTang2014/annoPeak . Contact gustavo.leone@osumc.edu or kun.huang@osumc.edu. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Xing Tang
- Department of Molecular Virology, Immunology and Medical Genetics College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, College of Biological Sciences, The Ohio State University, Columbus, OH, USA.,Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Arunima Srivastava
- Department of Molecular Virology, Immunology and Medical Genetics College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, College of Biological Sciences, The Ohio State University, Columbus, OH, USA.,Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Huayang Liu
- Department of Molecular Virology, Immunology and Medical Genetics College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, College of Biological Sciences, The Ohio State University, Columbus, OH, USA.,Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Raghu Machiraju
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH, USA
| | - Kun Huang
- Computer Science and Engineering, The Ohio State University, Columbus, OH, USA
| | - Gustavo Leone
- Department of Molecular Virology, Immunology and Medical Genetics College of Medicine, The Ohio State University, Columbus, OH, USA.,Department of Molecular Genetics, College of Biological Sciences, The Ohio State University, Columbus, OH, USA.,Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
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25
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Tai PWL, Wu H, van Wijnen AJ, Stein GS, Stein JL, Lian JB. Genome-wide DNase hypersensitivity, and occupancy of RUNX2 and CTCF reveal a highly dynamic gene regulome during MC3T3 pre-osteoblast differentiation. PLoS One 2017; 12:e0188056. [PMID: 29176792 PMCID: PMC5703546 DOI: 10.1371/journal.pone.0188056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/31/2017] [Indexed: 12/15/2022] Open
Abstract
The ability to discover regulatory sequences that control bone-related genes during development has been greatly improved by massively parallel sequencing methodologies. To expand our understanding of cis-regulatory regions critical to the control of gene expression during osteoblastogenesis, we probed the presence of open chromatin states across the osteoblast genome using global DNase hypersensitivity (DHS) mapping. Our profiling of MC3T3 mouse pre-osteoblasts during differentiation has identified more than 224,000 unique DHS sites. Approximately 65% of these sites are dynamic during temporal stages of osteoblastogenesis, and a majority of them are located within non-promoter (intergenic and intronic) regions. Nearly half of all DHS sites (both constitutive and dynamic) overlap binding events of the bone-essential RUNX2 and/or the chromatin-related CTCF transcription factors. This finding reinforces the role of these regulatory proteins as essential components of the bone gene regulome. We observe a reduction in chromatin accessibility throughout the genome between pre-osteoblast and early osteoblasts. Our analysis also defined a class of differentially expressed genes that harbor DHS peaks centered within 1 kb downstream of transcriptional end sites (TES). These DHSs at the 3’-flanks of genes exhibit dynamic changes during differentiation that may impact regulation of the osteoblast genome. Taken together, the distribution of DHS regions within non-promoter locations harboring osteoblast and chromatin related transcription factor binding motifs, reflect novel cis-regulatory requirements to support temporal gene expression in differentiating osteoblasts.
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Affiliation(s)
- Phillip W. L. Tai
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Hai Wu
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | | | - Gary S. Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Janet L. Stein
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
- * E-mail: (JLS); (JBL)
| | - Jane B. Lian
- Department of Biochemistry, University of Vermont College of Medicine, Burlington, Vermont, United States of America
- * E-mail: (JLS); (JBL)
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26
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Gaiti F, Jindrich K, Fernandez-Valverde SL, Roper KE, Degnan BM, Tanurdžić M. Landscape of histone modifications in a sponge reveals the origin of animal cis-regulatory complexity. eLife 2017; 6:22194. [PMID: 28395144 PMCID: PMC5429095 DOI: 10.7554/elife.22194] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 03/27/2017] [Indexed: 01/24/2023] Open
Abstract
Combinatorial patterns of histone modifications regulate developmental and cell type-specific gene expression and underpin animal complexity, but it is unclear when this regulatory system evolved. By analysing histone modifications in a morphologically-simple, early branching animal, the sponge Amphimedonqueenslandica, we show that the regulatory landscape used by complex bilaterians was already in place at the dawn of animal multicellularity. This includes distal enhancers, repressive chromatin and transcriptional units marked by H3K4me3 that vary with levels of developmental regulation. Strikingly, Amphimedon enhancers are enriched in metazoan-specific microsyntenic units, suggesting that their genomic location is extremely ancient and likely to place constraints on the evolution of surrounding genes. These results suggest that the regulatory foundation for spatiotemporal gene expression evolved prior to the divergence of sponges and eumetazoans, and was necessary for the evolution of animal multicellularity.
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Affiliation(s)
- Federico Gaiti
- School of Biological Sciences, University of Queensland, Brisbane, Australia
| | - Katia Jindrich
- School of Biological Sciences, University of Queensland, Brisbane, Australia
| | | | - Kathrein E Roper
- School of Biological Sciences, University of Queensland, Brisbane, Australia
| | - Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, Australia
| | - Miloš Tanurdžić
- School of Biological Sciences, University of Queensland, Brisbane, Australia
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27
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Han D, Chen Q, Shi J, Zhang F, Yu X. CTCF participates in DNA damage response via poly(ADP-ribosyl)ation. Sci Rep 2017; 7:43530. [PMID: 28262757 PMCID: PMC5337984 DOI: 10.1038/srep43530] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/27/2017] [Indexed: 01/15/2023] Open
Abstract
CCCTC-binding factor (CTCF) plays an essential role in regulating the structure of chromatin by binding DNA strands for defining the boundary between active and heterochromatic DNA. However, the role of CTCF in DNA damage response remains elusive. Here, we show that CTCF is quickly recruited to the sites of DNA damage. The fast recruitment is mediated by the zinc finger domain and poly (ADP-ribose) (PAR). Further analyses show that only three zinc finger motifs are essential for PAR recognition. Moreover, CTCF-deficient cells are hypersensitive to genotoxic stress such as ionizing radiation (IR). Taken together, these results suggest that CTCF participate in DNA damage response via poly(ADP-ribosylation).
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Affiliation(s)
- Deqiang Han
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, California, 91010, USA.,Department of Biochemistry and Molecular Biology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100005, China
| | - Qian Chen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, California, 91010, USA
| | - Jiazhong Shi
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, California, 91010, USA.,Department of Cell Biology, Third Military Medical University, Chongqing, 400038, China
| | - Feng Zhang
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, California, 91010, USA
| | - Xiaochun Yu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, California, 91010, USA
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28
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Gaiti F, Calcino AD, Tanurdžić M, Degnan BM. Origin and evolution of the metazoan non-coding regulatory genome. Dev Biol 2016; 427:193-202. [PMID: 27880868 DOI: 10.1016/j.ydbio.2016.11.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 11/14/2016] [Accepted: 11/18/2016] [Indexed: 02/09/2023]
Abstract
Animals rely on genomic regulatory systems to direct the dynamic spatiotemporal and cell-type specific gene expression that is essential for the development and maintenance of a multicellular lifestyle. Although it is widely appreciated that these systems ultimately evolved from genomic regulatory mechanisms present in single-celled stem metazoans, it remains unclear how this occurred. Here, we focus on the contribution of the non-coding portion of the genome to the evolution of animal gene regulation, specifically on recent insights from non-bilaterian metazoan lineages, and unicellular and colonial holozoan sister taxa. High-throughput next-generation sequencing, largely in bilaterian model species, has led to the discovery of tens of thousands of non-coding RNA genes (ncRNAs), including short, long and circular forms, and uncovered the central roles they play in development. Based on the analysis of non-bilaterian metazoan, unicellular holozoan and fungal genomes, the evolution of some ncRNAs, such as Piwi-interacting RNAs, correlates with the emergence of metazoan multicellularity, while others, including microRNAs, long non-coding RNAs and circular RNAs, appear to be more ancient. Analysis of non-coding regulatory DNA and histone post-translational modifications have revealed that some cis-regulatory mechanisms, such as those associated with proximal promoters, are present in non-animal holozoans, while others appear to be metazoan innovations, most notably distal enhancers. In contrast, the cohesin-CTCF system for regulating higher-order chromatin structure and enhancer-promoter long-range interactions appears to be restricted to bilaterians. Taken together, most bilaterian non-coding regulatory mechanisms appear to have originated before the divergence of crown metazoans. However, differential expansion of non-coding RNA and cis-regulatory DNA repertoires in bilaterians may account for their increased regulatory and morphological complexity relative to non-bilaterians.
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Affiliation(s)
- Federico Gaiti
- School of Biological Sciences, University of Queensland, Brisbane, Australia.
| | - Andrew D Calcino
- Department of Integrative Zoology, University of Vienna, Vienna, Austria.
| | - Miloš Tanurdžić
- School of Biological Sciences, University of Queensland, Brisbane, Australia.
| | - Bernard M Degnan
- School of Biological Sciences, University of Queensland, Brisbane, Australia.
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29
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Crystal structure of the DNA binding domain of the transcription factor T-bet suggests simultaneous recognition of distant genome sites. Proc Natl Acad Sci U S A 2016; 113:E6572-E6581. [PMID: 27791029 DOI: 10.1073/pnas.1613914113] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The transcription factor T-bet (Tbox protein expressed in T cells) is one of the master regulators of both the innate and adaptive immune responses. It plays a central role in T-cell lineage commitment, where it controls the TH1 response, and in gene regulation in plasma B-cells and dendritic cells. T-bet is a member of the Tbox family of transcription factors; however, T-bet coordinately regulates the expression of many more genes than other Tbox proteins. A central unresolved question is how T-bet is able to simultaneously recognize distant Tbox binding sites, which may be located thousands of base pairs away. We have determined the crystal structure of the Tbox DNA binding domain (DBD) of T-bet in complex with a palindromic DNA. The structure shows a quaternary structure in which the T-bet dimer has its DNA binding regions splayed far apart, making it impossible for a single dimer to bind both sites of the DNA palindrome. In contrast to most other Tbox proteins, a single T-bet DBD dimer binds simultaneously to identical half-sites on two independent DNA. A fluorescence-based assay confirms that T-bet dimers are able to bring two independent DNA molecules into close juxtaposition. Furthermore, chromosome conformation capture assays confirm that T-bet functions in the direct formation of chromatin loops in vitro and in vivo. The data are consistent with a looping/synapsing model for transcriptional regulation by T-bet in which a single dimer of the transcription factor can recognize and coalesce distinct genetic elements, either a promoter plus a distant regulatory element, or promoters on two different genes.
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30
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Allele-specific DNA methylation reinforces PEAR1 enhancer activity. Blood 2016; 128:1003-12. [PMID: 27313330 DOI: 10.1182/blood-2015-11-682153] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 06/13/2016] [Indexed: 01/07/2023] Open
Abstract
Genetic variation in the PEAR1 locus is linked to platelet reactivity and cardiovascular disease. The major G allele of rs12041331, an intronic cytosine guanine dinucleotide-single-nucleotide polymorphism (CpG-SNP), is associated with higher PEAR1 expression in platelets and endothelial cells than the minor A allele. The molecular mechanism underlying this difference remains elusive. We have characterized the histone modification profiles of the intronic region surrounding rs12041331 and identified H3K4Me1 enhancer-specific enrichment for the region that covers the CpG-SNP. Interestingly, methylation studies revealed that the CpG site is fully methylated in leukocytes of GG carriers. Nuclear protein extracts from megakaryocytes, endothelial cells, vs control HEK-293 cells show a 3-fold higher affinity for the methylated G allele compared with nonmethylated G or A alleles in a gel electrophoretic mobility shift assay. To understand the positive relationship between methylation and gene expression, we studied DNA methylation at 4 different loci of PEAR1 during in vitro megakaryopoiesis. During differentiation, the CpG-SNP remained fully methylated, while we observed rapid methylation increases at the CpG-island overlapping the first 5'-untranslated region exon, paralleling the increased PEAR1 expression. In the same region, A-allele carriers of rs12041331 showed significantly lower DNA methylation at CGI1 compared with GG homozygote. This CpG-island contains binding sites for the methylation-sensitive transcription factor CTCF, whose binding is known to play a role in enhancer activation and/or repression. In conclusion, we report the molecular characterization of the first platelet function-related CpG-SNP, a genetic predisposition that reinforces PEAR1 enhancer activity through allele-specific DNA methylation.
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31
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Zhao M, Wang J, Liao W, Li D, Li M, Wu H, Zhang Y, Gershwin ME, Lu Q. Increased 5-hydroxymethylcytosine in CD4 + T cells in systemic lupus erythematosus. J Autoimmun 2016; 69:64-73. [DOI: 10.1016/j.jaut.2016.03.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 02/26/2016] [Accepted: 03/01/2016] [Indexed: 12/16/2022]
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32
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Boersma GJ, Liang NC, Lee RS, Albertz JD, Kastelein A, Moody LA, Aryal S, Moran TH, Tamashiro KL. Failure to upregulate Agrp and Orexin in response to activity based anorexia in weight loss vulnerable rats characterized by passive stress coping and prenatal stress experience. Psychoneuroendocrinology 2016; 67:171-81. [PMID: 26907996 PMCID: PMC4808341 DOI: 10.1016/j.psyneuen.2016.02.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/29/2016] [Accepted: 02/03/2016] [Indexed: 02/02/2023]
Abstract
We hypothesize that anorexia nervosa (AN) poses a physiological stress. Therefore, the way an individual copes with stress may affect AN vulnerability. Since prenatal stress (PNS) exposure alters stress responsivity in offspring this may increase their risk of developing AN. We tested this hypothesis using the activity based anorexia (ABA) rat model in control and PNS rats that were characterized by either proactive or passive stress-coping behavior. We found that PNS passively coping rats ate less and lost more weight during the ABA paradigm. Exposure to ABA resulted in higher baseline corticosterone and lower insulin levels in all groups. However, leptin levels were only decreased in rats with a proactive stress-coping style. Similarly, ghrelin levels were increased only in proactively coping ABA rats. Neuropeptide Y (Npy) expression was increased and proopiomelanocortin (Pomc) expression was decreased in all rats exposed to ABA. In contrast, agouti-related peptide (Agrp) and orexin (Hctr) expression were increased in all but the PNS passively coping ABA rats. Furthermore, DNA methylation of the orexin gene was increased after ABA in proactive coping rats and not in passive coping rats. Overall our study suggests that passive PNS rats have innate impairments in leptin and ghrelin in responses to starvation combined with prenatal stress associated impairments in Agrp and orexin expression in response to starvation. These impairments may underlie decreased food intake and associated heightened body weight loss during ABA in the passively coping PNS rats.
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33
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Sergeeva IA, Hooijkaas IB, Ruijter JM, van der Made I, de Groot NE, van de Werken HJG, Creemers EE, Christoffels VM. Identification of a regulatory domain controlling the Nppa-Nppb gene cluster during heart development and stress. Development 2016; 143:2135-46. [PMID: 27048739 DOI: 10.1242/dev.132019] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 03/29/2016] [Indexed: 12/28/2022]
Abstract
The paralogous genes Nppa and Nppb are organized in an evolutionarily conserved cluster and provide a valuable model for studying co-regulation and regulatory landscape organization during heart development and disease. Here, we analyzed the chromatin conformation, epigenetic status and enhancer potential of sequences of the Nppa-Nppb cluster in vivo Our data indicate that the regulatory landscape of the cluster is present within a 60-kb domain centered around Nppb Both promoters and several potential regulatory elements interact with each other in a similar manner in different tissues and developmental stages. The distribution of H3K27ac and the association of Pol2 across the locus changed during cardiac hypertrophy, revealing their potential involvement in stress-mediated gene regulation. Functional analysis of double-reporter transgenic mice revealed that Nppa and Nppb share developmental, but not stress-response, enhancers, responsible for their co-regulation. Moreover, the Nppb promoter was required, but not sufficient, for hypertrophy-induced Nppa expression. In summary, the developmental regulation and stress response of the Nppa-Nppb cluster involve the concerted action of multiple enhancers and epigenetic changes distributed across a structurally rigid regulatory domain.
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Affiliation(s)
- Irina A Sergeeva
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Ingeborg B Hooijkaas
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Jan M Ruijter
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Ingeborg van der Made
- Department of Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Nina E de Groot
- Department of Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Harmen J G van de Werken
- Cancer Computational Biology Center, Wytemaweg 80, Erasmus MC Cancer Institute, Erasmus MC, Rotterdam 3015 CN, The Netherlands
| | - Esther E Creemers
- Department of Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Vincent M Christoffels
- Department of Anatomy, Embryology and Physiology, Academic Medical Center, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
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Wiechens N, Singh V, Gkikopoulos T, Schofield P, Rocha S, Owen-Hughes T. The Chromatin Remodelling Enzymes SNF2H and SNF2L Position Nucleosomes adjacent to CTCF and Other Transcription Factors. PLoS Genet 2016; 12:e1005940. [PMID: 27019336 PMCID: PMC4809547 DOI: 10.1371/journal.pgen.1005940] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 02/25/2016] [Indexed: 12/22/2022] Open
Abstract
Within the genomes of metazoans, nucleosomes are highly organised adjacent to the binding sites for a subset of transcription factors. Here we have sought to investigate which chromatin remodelling enzymes are responsible for this. We find that the ATP-dependent chromatin remodelling enzyme SNF2H plays a major role organising arrays of nucleosomes adjacent to the binding sites for the architectural transcription factor CTCF sites and acts to promote CTCF binding. At many other factor binding sites SNF2H and the related enzyme SNF2L contribute to nucleosome organisation. The action of SNF2H at CTCF sites is functionally important as depletion of CTCF or SNF2H affects transcription of a common group of genes. This suggests that chromatin remodelling ATPase's most closely related to the Drosophila ISWI protein contribute to the function of many human gene regulatory elements.
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Affiliation(s)
- Nicola Wiechens
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Vijender Singh
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Triantaffyllos Gkikopoulos
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Pieta Schofield
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sonia Rocha
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Tom Owen-Hughes
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dundee, United Kingdom
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Satb1 Overexpression Drives Tumor-Promoting Activities in Cancer-Associated Dendritic Cells. Cell Rep 2016; 14:1774-1786. [PMID: 26876172 DOI: 10.1016/j.celrep.2016.01.056] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/14/2015] [Accepted: 01/14/2016] [Indexed: 02/07/2023] Open
Abstract
Special AT-rich sequence-binding protein 1 (Satb1) governs genome-wide transcriptional programs. Using a conditional knockout mouse, we find that Satb1 is required for normal differentiation of conventional dendritic cells (DCs). Furthermore, Satb1 governs the differentiation of inflammatory DCs by regulating major histocompatibility complex class II (MHC II) expression through Notch1 signaling. Mechanistically, Satb1 binds to the Notch1 promoter, activating Notch expression and driving RBPJ occupancy of the H2-Ab1 promoter, which activates MHC II transcription. However, tumor-driven, unremitting expression of Satb1 in activated Zbtb46(+) inflammatory DCs that infiltrate ovarian tumors results in an immunosuppressive phenotype characterized by increased secretion of tumor-promoting Galectin-1 and IL-6. In vivo silencing of Satb1 in tumor-associated DCs reverses their tumorigenic activity and boosts protective immunity. Therefore, dynamic fluctuations in Satb1 expression govern the generation and immunostimulatory activity of steady-state and inflammatory DCs, but continuous Satb1 overexpression in differentiated DCs converts them into tolerogenic/pro-inflammatory cells that contribute to malignant progression.
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Abstract
Splicing is a predominantly co-transcriptional process that has been shown to be tightly coupled to transcription. Chromatin structure is a key factor that mediates this functional coupling. In light of recent evidence that shows the importance of higher order chromatin organization in the coordination and regulation of gene expression, we discuss here the possible roles of long-range chromatin organization in splicing and alternative splicing regulation.
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Affiliation(s)
- Luciana I Gómez Acuña
- a Laboratorio de Fisiología y Biología Molecular, Departamento de Fisiología, Biología Molecular y Celular, IFIBYNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires; Buenos Aires, Argentina
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Long-Range Transcriptional Control of the Il2 Gene by an Intergenic Enhancer. Mol Cell Biol 2015; 35:3880-91. [PMID: 26351138 DOI: 10.1128/mcb.00592-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/28/2015] [Indexed: 02/08/2023] Open
Abstract
Interleukin-2 (IL-2) is a potent cytokine with roles in both immunity and tolerance. Genetic studies in humans and mice demonstrate a role for Il2 in autoimmune disease susceptibility, and for decades the proximal Il2 upstream regulatory region has served as a paradigm of tissue-specific, inducible gene regulation. In this study, we have identified a novel long-range enhancer of the Il2 gene located 83 kb upstream of the transcription start site. This element can potently enhance Il2 transcription in recombinant reporter assays in vitro, and the native region undergoes chromatin remodeling, transcribes a bidirectional enhancer RNA, and loops to physically interact with the Il2 gene in vivo in a CD28-dependent manner in CD4(+) T cells. This cis regulatory element is evolutionarily conserved and is situated near a human single-nucleotide polymorphism (SNP) associated with multiple autoimmune disorders. These results indicate that the regulatory architecture of the Il2 locus is more complex than previously appreciated and suggest a novel molecular basis for the genetic association of Il2 polymorphism with autoimmune disease.
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Maksimenko O, Gasanov NB, Georgiev P. Regulatory Elements in Vectors for Efficient Generation of Cell Lines Producing Target Proteins. Acta Naturae 2015; 7:15-26. [PMID: 26483956 PMCID: PMC4610161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To date, there has been an increasing number of drugs produced in mammalian cell cultures. In order to enhance the expression level and stability of target recombinant proteins in cell cultures, various regulatory elements with poorly studied mechanisms of action are used. In this review, we summarize and discuss the potential mechanisms of action of such regulatory elements.
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Affiliation(s)
- O. Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, 119334, Moscow, Russia
| | - N. B. Gasanov
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, 119334, Moscow, Russia
| | - P. Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, 119334, Moscow, Russia
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Long-range epigenetic regulation is conferred by genetic variation located at thousands of independent loci. Nat Commun 2015; 6:6326. [PMID: 25716334 PMCID: PMC4351585 DOI: 10.1038/ncomms7326] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/19/2015] [Indexed: 01/06/2023] Open
Abstract
The interplay between genetic and epigenetic variation is only partially understood. One form of epigenetic variation is methylation at CpG sites, which can be measured as methylation quantitative trait loci (meQTL). Here we report that in a panel of lymphocytes from 1,748 individuals, methylation levels at 1,919 CpG sites are correlated with at least one distal (trans) single-nucleotide polymorphism (SNP) (P<3.2 × 10(-13); FDR<5%). These trans-meQTLs include 1,657 SNP-CpG pairs from different chromosomes and 262 pairs from the same chromosome that are >1 Mb apart. Over 90% of these pairs are replicated (FDR<5%) in at least one of two independent data sets. Genomic loci harbouring trans-meQTLs are significantly enriched (P<0.001) for long non-coding transcripts (2.2-fold), known epigenetic regulators (2.3-fold), piwi-interacting RNA clusters (3.6-fold) and curated transcription factors (4.1-fold), including zinc-finger proteins (8.75-fold). Long-range epigenetic networks uncovered by this approach may be relevant to normal and disease states.
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40
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Grzeda KR, Royer-Bertrand B, Inaki K, Kim H, Hillmer AM, Liu ET, Chuang JH. Functional chromatin features are associated with structural mutations in cancer. BMC Genomics 2014; 15:1013. [PMID: 25417144 PMCID: PMC4253614 DOI: 10.1186/1471-2164-15-1013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/12/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Structural mutations (SMs) play a major role in cancer development. In some cancers, such as breast and ovarian, DNA double-strand breaks (DSBs) occur more frequently in transcribed regions, while in other cancer types such as prostate, there is a consistent depletion of breakpoints in transcribed regions. Despite such regularity, little is understood about the mechanisms driving these effects. A few works have suggested that protein binding may be relevant, e.g. in studies of androgen receptor binding and active chromatin in specific cell types. We hypothesized that this behavior might be general, i.e. that correlation between protein-DNA binding (and open chromatin) and breakpoint locations is common across divergent cancers. RESULTS We investigated this hypothesis by comprehensively analyzing the relationship among 457 ENCODE protein binding ChIP-seq experiments, 125 DnaseI and 24 FAIRE experiments, and 14,600 SMs from 8 diverse cancer datasets covering 147 samples. In most cancers, including breast and ovarian, we found enrichment of protein binding and open chromatin in the vicinity of SM breakpoints at distances up to 200 kb. Furthermore, for all cancer types we observed an enhanced enrichment in regions distant from genes when compared to regions proximal to genes, suggesting that the SM-induction mechanism is independent from the bias of DSBs to occur near transcribed regions. We also observed a stronger effect for sites with more than one protein bound. CONCLUSIONS Protein binding and open chromatin state are associated with nearby SM breakpoints in many cancer datasets. These observations suggest a consistent mechanism underlying SM locations across different cancers.
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Affiliation(s)
- Krzysztof R Grzeda
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
| | - Beryl Royer-Bertrand
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
- />Department of Medical Genetics, University of Lausanne, 1005 Lausanne, Switzerland
| | - Koichiro Inaki
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
| | - Hyunsoo Kim
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
| | - Axel M Hillmer
- />Genome Technology and Biology, Genome Institute of Singapore, Singapore, 138672 Singapore
| | - Edison T Liu
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
- />The Jackson Laboratory, Bar Harbor, ME 04609 USA
| | - Jeffrey H Chuang
- />The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06030 USA
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Quantitative genetics of CTCF binding reveal local sequence effects and different modes of X-chromosome association. PLoS Genet 2014; 10:e1004798. [PMID: 25411781 PMCID: PMC4238955 DOI: 10.1371/journal.pgen.1004798] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 10/02/2014] [Indexed: 11/19/2022] Open
Abstract
Associating genetic variation with quantitative measures of gene regulation offers a way to bridge the gap between genotype and complex phenotypes. In order to identify quantitative trait loci (QTLs) that influence the binding of a transcription factor in humans, we measured binding of the multifunctional transcription and chromatin factor CTCF in 51 HapMap cell lines. We identified thousands of QTLs in which genotype differences were associated with differences in CTCF binding strength, hundreds of them confirmed by directly observable allele-specific binding bias. The majority of QTLs were either within 1 kb of the CTCF binding motif, or in linkage disequilibrium with a variant within 1 kb of the motif. On the X chromosome we observed three classes of binding sites: a minority class bound only to the active copy of the X chromosome, the majority class bound to both the active and inactive X, and a small set of female-specific CTCF sites associated with two non-coding RNA genes. In sum, our data reveal extensive genetic effects on CTCF binding, both direct and indirect, and identify a diversity of patterns of CTCF binding on the X chromosome.
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42
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Schoborg T, Labrador M. Expanding the roles of chromatin insulators in nuclear architecture, chromatin organization and genome function. Cell Mol Life Sci 2014; 71:4089-113. [PMID: 25012699 PMCID: PMC11113341 DOI: 10.1007/s00018-014-1672-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 01/08/2023]
Abstract
Of the numerous classes of elements involved in modulating eukaryotic chromosome structure and function, chromatin insulators arguably remain the most poorly understood in their contribution to these processes in vivo. Indeed, our view of chromatin insulators has evolved dramatically since their chromatin boundary and enhancer blocking properties were elucidated roughly a quarter of a century ago as a result of recent genome-wide, high-throughput methods better suited to probing the role of these elements in their native genomic contexts. The overall theme that has emerged from these studies is that chromatin insulators function as general facilitators of higher-order chromatin loop structures that exert both physical and functional constraints on the genome. In this review, we summarize the result of recent work that supports this idea as well as a number of other studies linking these elements to a diverse array of nuclear processes, suggesting that chromatin insulators exert master control over genome organization and behavior.
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Affiliation(s)
- Todd Schoborg
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
- Present Address: Laboratory of Molecular Machines and Tissue Architecture, Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Dr Rm 2122, Bethesda, MD 20892 USA
| | - Mariano Labrador
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, M407 Walters Life Sciences, 1414 Cumberland Avenue, Knoxville, TN 37996 USA
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Franco MM, Prickett AR, Oakey RJ. The role of CCCTC-binding factor (CTCF) in genomic imprinting, development, and reproduction. Biol Reprod 2014; 91:125. [PMID: 25297545 DOI: 10.1095/biolreprod.114.122945] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
CCCTC-binding factor (CTCF) is the major protein involved in insulator activity in vertebrates, with widespread DNA binding sites in the genome. CTCF participates in many processes related to global chromatin organization and remodeling, contributing to the repression or activation of gene transcription. It is also involved in epigenetic reprogramming and is essential during gametogenesis and embryo development. Abnormal DNA methylation patterns at CTCF motifs may impair CTCF binding to DNA, and are related to fertility disorders in mammals. Therefore, CTCF and its binding sites are important candidate regions to be investigated as molecular markers for gamete and embryo quality. This article reviews the role of CTCF in genomic imprinting, gametogenesis, and early embryo development and, moreover, highlights potential opportunities for environmental influences associated with assisted reproductive techniques (ARTs) to affect CTCF-mediated processes. We discuss the potential use of CTCF as a molecular marker for assessing gamete and embryo quality in the context of improving the efficiency and safety of ARTs.
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Affiliation(s)
- Maurício M Franco
- Embrapa Genetic Resources & Biotechnology, Laboratory of Animal Reproduction, Parque Estação Biológica, Brasília, Brazil
| | - Adam R Prickett
- Department of Medical & Molecular Genetics, King's College London, Guy's Hospital, London, United Kingdom
| | - Rebecca J Oakey
- Department of Medical & Molecular Genetics, King's College London, Guy's Hospital, London, United Kingdom
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Pike JW, Meyer MB. Fundamentals of vitamin D hormone-regulated gene expression. J Steroid Biochem Mol Biol 2014; 144 Pt A:5-11. [PMID: 24239506 PMCID: PMC4144817 DOI: 10.1016/j.jsbmb.2013.11.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 10/24/2013] [Accepted: 11/05/2013] [Indexed: 12/20/2022]
Abstract
Initial research focused upon several known genetic targets provided early insight into the mechanism of action of the vitamin D hormone (1,25-dihydroxyvitamin D3 (1,25(OH)2D3)). Recently, however, a series of technical advances involving the coupling of chromatin immunoprecipitation (ChIP) to unbiased methodologies that initially involved tiled DNA microarrays (ChIP-chip analysis) and now Next Generation DNA Sequencing techniques (ChIP-seq analysis) has opened new avenues of research into the mechanisms through which 1,25(OH)2D3 regulates gene expression. In this review, we summarize briefly the results of this early work and then focus on more recent studies in which ChIP-chip and ChIP-seq analyses have been used to explore the mechanisms of 1,25(OH)2D3 action on a genome-wide scale providing specific target genes as examples. The results of this work have advanced our understanding of the mechanisms involved at both genetic and epigenetic levels and have revealed a series of new principles through which the vitamin D hormone functions to control the expression of genes. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.
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Affiliation(s)
- J Wesley Pike
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States.
| | - Mark B Meyer
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, United States
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Seuter S, Ryynänen J, Carlberg C. The ASAP2 gene is a primary target of 1,25-dihydroxyvitamin D3 in human monocytes and macrophages. J Steroid Biochem Mol Biol 2014; 144 Pt A:12-8. [PMID: 23999061 DOI: 10.1016/j.jsbmb.2013.08.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 08/05/2013] [Accepted: 08/19/2013] [Indexed: 10/26/2022]
Abstract
A genome-wide data set on vitamin D receptor (VDR) binding sites in human THP-1 cells (monocytes) led us to the genomic region around the ASAP2 (Arf-GAP with SH3 domain, ankyrin repeat and PH domain 2) gene, whose product is involved in the regulation of vesicular transport, cellular migration and autophagy. Using ENCODE data, we demonstrated that the ASAP2 gene is flanked by conserved binding sites of the insulating transcription factor CTCF. These sites define different chromosomal domains containing the ASAP2 gene, up to six additional genes and three VDR binding sites. In human monocytes (THP-1 cells) the ASAP2 gene is more weakly expressed but more and faster inducible by the biologically active form of vitamin D, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), than in M2-type macrophages (phorbol ester-differentiated THP-1 cells). Within the investigated genomic region, the basal mRNA expressions of the neighboring genes are comparably high in both monocytes and macrophages, but the ASAP2 gene is the only primary 1,25(OH)2D3 target. The three VDR binding sites located 54, 436 and 574kb downstream of the ASAP2 transcription start site each carry a sequence formed by a direct repeat with three intervening nucleotides (DR3). Ligand-inducible VDR binding was confirmed to all three genomic sites in monocytes and macrophages. Taken together, the region around the ASAP2 gene is genome-wide highlighted as a special attraction point for the VDR, but the presently sole known functional consequence of the binding of VDR to three sites within this chromosomal region is that ASAP2 is a primary 1,25(OH)2D3 target gene in monocytes and macrophages. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.
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Affiliation(s)
- Sabine Seuter
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Jussi Ryynänen
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Carsten Carlberg
- School of Medicine, Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland.
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46
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Wu M, Kwoh CK, Li X, Zheng J. Finding trans-regulatory genes and protein complexes modulating meiotic recombination hotspots of human, mouse and yeast. BMC SYSTEMS BIOLOGY 2014; 8:107. [PMID: 25208583 PMCID: PMC4236725 DOI: 10.1186/s12918-014-0107-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 07/11/2014] [Indexed: 11/18/2022]
Abstract
Background The regulatory mechanism of recombination is one of the most fundamental problems in genomics, with wide applications in genome wide association studies (GWAS), birth-defect diseases, molecular evolution, cancer research, etc. Recombination events cluster into short genomic regions called “recombination hotspots”. Recently, a zinc finger protein PRDM9 was reported to regulate recombination hotspots in human and mouse genomes. In addition, a 13-mer motif contained in the binding sites of PRDM9 is found to be enriched in human hotspots. However, this 13-mer motif only covers a fraction of hotspots, indicating that PRDM9 is not the only regulator of recombination hotspots. Therefore, the challenge of discovering other regulators of recombination hotspots becomes significant. Furthermore, recombination is a complex process. Hence, multiple proteins acting as machinery, rather than individual proteins, are more likely to carry out this process in a precise and stable manner. Therefore, the extension of the prediction of individual trans-regulators to protein complexes is also highly desired. Results In this paper, we introduce a pipeline to identify genes and protein complexes associated with recombination hotspots. First, we prioritize proteins associated with hotspots based on their preference of binding to hotspots and coldspots. Second, using the above identified genes as seeds, we apply the Random Walk with Restart algorithm (RWR) to propagate their influences to other proteins in protein-protein interaction (PPI) networks. Hence, many proteins without DNA-binding information will also be assigned a score to implicate their roles in recombination hotspots. Third, we construct sub-PPI networks induced by top genes ranked by RWR for various species (e.g., yeast, human and mouse) and detect protein complexes in those sub-PPI networks. Conclusions The GO term analysis show that our prioritizing methods and the RWR algorithm are capable of identifying novel genes associated with recombination hotspots. The trans-regulators predicted by our pipeline are enriched with epigenetic functions (e.g., histone modifications), demonstrating the epigenetic regulatory mechanisms of recombination hotspots. The identified protein complexes also provide us with candidates to further investigate the molecular machineries for recombination hotspots. Moreover, the experimental data and results are available on our web site http://www.ntu.edu.sg/home/zhengjie/data/RecombinationHotspot/NetPipe/.
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47
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Dubois-Chevalier J, Oger F, Dehondt H, Firmin FF, Gheeraert C, Staels B, Lefebvre P, Eeckhoute J. A dynamic CTCF chromatin binding landscape promotes DNA hydroxymethylation and transcriptional induction of adipocyte differentiation. Nucleic Acids Res 2014; 42:10943-59. [PMID: 25183525 PMCID: PMC4176165 DOI: 10.1093/nar/gku780] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
CCCTC-binding factor (CTCF) is a ubiquitously expressed multifunctional transcription factor characterized by chromatin binding patterns often described as largely invariant. In this context, how CTCF chromatin recruitment and functionalities are used to promote cell type-specific gene expression remains poorly defined. Here, we show that, in addition to constitutively bound CTCF binding sites (CTS), the CTCF cistrome comprises a large proportion of sites showing highly dynamic binding patterns during the course of adipogenesis. Interestingly, dynamic CTCF chromatin binding is positively linked with changes in expression of genes involved in biological functions defining the different stages of adipogenesis. Importantly, a subset of these dynamic CTS are gained at cell type-specific regulatory regions, in line with a requirement for CTCF in transcriptional induction of adipocyte differentiation. This relates to, at least in part, CTCF requirement for transcriptional activation of both the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARG) and its target genes. Functionally, we show that CTCF interacts with TET methylcytosine dioxygenase (TET) enzymes and promotes adipogenic transcriptional enhancer DNA hydroxymethylation. Our study reveals a dynamic CTCF chromatin binding landscape required for epigenomic remodeling of enhancers and transcriptional activation driving cell differentiation.
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Affiliation(s)
- Julie Dubois-Chevalier
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Frédérik Oger
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Hélène Dehondt
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - François F Firmin
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Céline Gheeraert
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Bart Staels
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Philippe Lefebvre
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
| | - Jérôme Eeckhoute
- Inserm UMR U1011, F-59000 Lille, France Université Lille 2, F-59000 Lille, France Institut Pasteur de Lille, F-59019 Lille, France European Genomic Institute for Diabetes (EGID), FR 3508, F-59000 Lille, France
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48
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Abstract
ENCODE projects exist for many eukaryotes, including humans, but as of yet no defined project exists for plants. A plant ENCODE would be invaluable to the research community and could be more readily produced than its metazoan equivalents by capitalizing on the preexisting infrastructure provided from similar projects. Collecting and normalizing plant epigenomic data for a range of species will facilitate hypothesis generation, cross-species comparisons, annotation of genomes, and an understanding of epigenomic functions throughout plant evolution. Here, we discuss the need for such a project, outline the challenges it faces, and suggest ways forward to build a plant ENCODE.
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Affiliation(s)
- Amanda K Lane
- Department of Genetics, University of Georgia, Athens, Georgia 30602;
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49
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Abstract
Advancements in sequencing techniques have led to the discovery of numerous genes not previously implicated in acute myeloid leukemia (AML) biology. Further in vivo studies are necessary to discern the biological impact of these mutations. Murine models, the most commonly used in vivo system, provide a physiologic context for the study of specific genes. These systems have provided deep insights into the role of genetic translocations, mutations, and dysregulated gene expression on leukemia pathogenesis. This review focuses on the phenotype of newly identified genes, including NPM1, IDH1/2, TET2, MLL, DNMT3A, EZH2, EED, and ASXL1, in mouse models and the implications on AML biology.
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Affiliation(s)
- Ashley M Perry
- Massachusetts General Hospital Cancer Center, Boston, MA
| | - Eyal C Attar
- Massachusetts General Hospital Cancer Center, Boston, MA.
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Transcriptional regulation and spatial interactions of head-to-head genes. BMC Genomics 2014; 15:519. [PMID: 24962804 PMCID: PMC4089025 DOI: 10.1186/1471-2164-15-519] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 06/19/2014] [Indexed: 11/10/2022] Open
Abstract
Background In eukaryotic genomes, about 10% of genes are arranged in a head-to-head (H2H) orientation, and the distance between the transcription start sites of each gene pair is closer than 1 kb. Two genes in an H2H pair are prone to co-express and co-function. There have been many studies on bidirectional promoters. However, the mechanism by which H2H genes are regulated at the transcriptional level still needs further clarification, especially with regard to the co-regulation of H2H pairs. In this study, we first used the Hi-C data of chromatin linkages to identify spatially interacting H2H pairs, and then integrated ChIP-seq data to compare H2H gene pairs with and without evidence of spatial interactions in terms of their binding transcription factors (TFs). Using ChIP-seq and DNase-seq data, histones and DNase associated with H2H pairs were identified. Furthermore, we looked into the connections between H2H genes in a human co-expression network. Results We found that i) Similar to the behaviour of two genes within an H2H pair (intra-H2H pair), a gene pair involving two distinct H2H pairs (inter-H2H pair) which interact with each other spatially, share common transcription factors (TFs); ii) TFs of intra- and inter-H2H pairs are distributed differently. Factors such as HEY1, GABP, Sin3Ak-20, POL2, E2F6, and c-MYC are essential for the bidirectional transcription of intra-H2H pairs; while factors like CTCF, BDP1, GATA2, RAD21, and POL3 play important roles in coherently regulating inter-H2H pairs; iii) H2H gene blocks are enriched with hypersensitive DNase and modified histones, which participate in active transcriptions; and iv) H2H genes tend to be highly connected compared with non-H2H genes in the human co-expression network. Conclusions Our findings shed new light on the mechanism of the transcriptional regulation of H2H genes through their linear and spatial interactions. For intra-H2H gene pairs, transcription factors regulate their transcriptions through bidirectional promoters, whereas for inter-H2H gene pairs, transcription factors are likely to regulate their activities depending on the spatial interaction of H2H gene pairs. In this way, two distinctive groups of transcription factors mediate intra- and inter-H2H gene transcriptions respectively, resulting in a highly compact gene regulatory network. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-519) contains supplementary material, which is available to authorized users.
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