1
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Wang X, Yue F. Hijacked enhancer-promoter and silencer-promoter loops in cancer. Curr Opin Genet Dev 2024; 86:102199. [PMID: 38669773 DOI: 10.1016/j.gde.2024.102199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 03/19/2024] [Accepted: 04/07/2024] [Indexed: 04/28/2024]
Abstract
Recent work has shown that besides inducing fusion genes, structural variations (SVs) can also contribute to oncogenesis by disrupting the three-dimensional genome organization and dysregulating gene expression. At the chromatin-loop level, SVs can relocate enhancers or silencers from their original genomic loci to activate oncogenes or repress tumor suppressor genes. On a larger scale, different types of alterations in topologically associating domains (TADs) have been reported in cancer, such as TAD expansion, shuffling, and SV-induced neo-TADs. Furthermore, the transformation from normal cells to cancerous cells is usually coupled with active or repressive compartmental switches, and cancer-specific compartments have been proposed. This review discusses the sites, and the other latest advances in studying how SVs disrupt higher-order genome structure in cancer, which in turn leads to oncogene dysregulation. We also highlight the clinical implications of these changes and the challenges ahead in this field.
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Affiliation(s)
- Xiaotao Wang
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China; Shanghai Key Laboratory of Reproduction and Development, Shanghai, China.
| | - Feng Yue
- Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine Northwestern University, Chicago, Illinois, USA; Robert H. Lurie Comprehensive Cancer Center of Northwestern University, Chicago, Illinois, USA.
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2
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Câmara AS, Kubalová I, Schubert V. Helical chromonema coiling is conserved in eukaryotes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1284-1300. [PMID: 37840457 DOI: 10.1111/tpj.16484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 09/07/2023] [Accepted: 09/13/2023] [Indexed: 10/17/2023]
Abstract
Efficient chromatin condensation is required to transport chromosomes during mitosis and meiosis, forming daughter cells. While it is well accepted that these processes follow fundamental rules, there has been a controversial debate for more than 140 years on whether the higher-order chromatin organization in chromosomes is evolutionarily conserved. Here, we summarize historical and recent investigations based on classical and modern methods. In particular, classical light microscopy observations based on living, fixed, and treated chromosomes covering a wide range of plant and animal species, and even in single-cell eukaryotes suggest that the chromatids of large chromosomes are formed by a coiled chromatin thread, named the chromonema. More recently, these findings were confirmed by electron and super-resolution microscopy, oligo-FISH, molecular interaction data, and polymer simulation. Altogether, we describe common and divergent features of coiled chromonemata in different species. We hypothesize that chromonema coiling in large chromosomes is a fundamental feature established early during the evolution of eukaryotes to handle increasing genome sizes.
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Affiliation(s)
- Amanda Souza Câmara
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| | - Ivona Kubalová
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, D-06466, Seeland, Germany
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3
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Klutstein M, Gonen N. Epigenetic aging of mammalian gametes. Mol Reprod Dev 2023; 90:785-803. [PMID: 37997675 DOI: 10.1002/mrd.23717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 11/09/2023] [Accepted: 11/12/2023] [Indexed: 11/25/2023]
Abstract
The process of aging refers to physiological changes that occur to an organism as time progresses and involves changes to DNA, proteins, metabolism, cells, and organs. Like the rest of the cells in the body, gametes age, and it is well established that there is a decline in reproductive capabilities in females and males with aging. One of the major pathways known to be involved in aging is epigenetic changes. The epigenome is the multitude of chemical modifications performed on DNA and chromatin that affect the ability of chromatin to be transcribed. In this review, we explore the effects of aging on female and male gametes with a focus on the epigenetic changes that occur in gametes throughout aging. Quality decline in oocytes occurs at a relatively early age. Epigenetic changes constitute an important part of oocyte aging. DNA methylation is reduced with age, along with reduced expression of DNA methyltransferases (DNMTs). Histone deacetylases (HDAC) expression is also reduced, and a loss of heterochromatin marks occurs with age. As a consequence of heterochromatin loss, retrotransposon expression is elevated, and aged oocytes suffer from DNA damage. In sperm, aging affects sperm number, motility and fecundity, and epigenetic changes may constitute a part of this process. 5 methyl-cytosine (5mC) methylation is elevated in sperm from aged men, but methylation on Long interspersed nuclear elements (LINE) elements is reduced. Di and trimethylation of histone 3 lysine 9 (H3K9me2/3) is reduced in sperm from aged men and trimethylation of histone 3 lysine 27 (H3K27me3) is elevated. The protamine makeup of sperm from aged men is also changed, with reduced protamine expression and a misbalanced ratio between protamine proteins protamine P1 and protamine P2. The study of epigenetic reproductive aging is recently gaining interest. The current status of the field suggests that many aspects of gamete epigenetic aging are still open for investigation. The clinical applications of these investigations have far-reaching consequences for fertility and sociological human behavior.
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Affiliation(s)
- Michael Klutstein
- Institute of Biomedical and Oral Research, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nitzan Gonen
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
- Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
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4
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Soujanya M, Bihani A, Hajirnis N, Pathak RU, Mishra RK. Nuclear architecture and the structural basis of mitotic memory. CHROMOSOME RESEARCH : AN INTERNATIONAL JOURNAL ON THE MOLECULAR, SUPRAMOLECULAR AND EVOLUTIONARY ASPECTS OF CHROMOSOME BIOLOGY 2023; 31:8. [PMID: 36725757 DOI: 10.1007/s10577-023-09714-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/13/2022] [Accepted: 12/19/2022] [Indexed: 02/03/2023]
Abstract
The nucleus is a complex organelle that hosts the genome and is essential for vital processes like DNA replication, DNA repair, transcription, and splicing. The genome is non-randomly organized in the three-dimensional space of the nucleus. This functional sub-compartmentalization was thought to be organized on the framework of nuclear matrix (NuMat), a non-chromatin scaffold that functions as a substratum for various molecular processes of the nucleus. More recently, nuclear bodies or membrane-less subcompartments of the nucleus are thought to arise due to phase separation of chromatin, RNA, and proteins. The nuclear architecture is an amalgamation of the relative organization of chromatin, epigenetic landscape, the nuclear bodies, and the nucleoskeleton in the three-dimensional space of the nucleus. During mitosis, the nucleus undergoes drastic changes in morphology to the degree that it ceases to exist as such; various nuclear components, including the envelope that defines the nucleus, disintegrate, and the chromatin acquires mitosis-specific epigenetic marks and condenses to form chromosome. Upon mitotic exit, chromosomes are decondensed, re-establish hierarchical genome organization, and regain epigenetic and transcriptional status similar to that of the mother cell. How this mitotic memory is inherited during cell division remains a puzzle. NuMat components that are a part of the mitotic chromosome in the form of mitotic chromosome scaffold (MiCS) could potentially be the seeds that guide the relative re-establishment of the epigenome, chromosome territories, and the nuclear bodies. Here, we synthesize the advances towards understanding cellular memory of nuclear architecture across mitosis and propose a hypothesis that a subset of NuMat proteome essential for nucleation of various nuclear bodies are retained in MiCS to serve as seeds of mitotic memory, thus ensuring the daughter cells re-establish the complex status of nuclear architecture similar to that of the mother cells, thereby maintaining the pre-mitotic transcriptional status.
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Affiliation(s)
- Mamilla Soujanya
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
- AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Ashish Bihani
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
| | - Nikhil Hajirnis
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
- Department of Anatomy and Neurobiology, University of Maryland, Baltimore, USA
| | - Rashmi U Pathak
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India
| | - Rakesh K Mishra
- CSIR - Centre for Cellular & Molecular Biology, Hyderabad, India.
- AcSIR - Academy of Scientific and Innovative Research, Ghaziabad, India.
- TIGS - Tata Institute for Genetics and Society, Bangalore, India.
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5
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Abstract
Dramatic nuclear reorganization occurs during early development to convert terminally differentiated gametes to a totipotent zygote, which then gives rise to an embryo. Aberrant epigenome resetting severely impairs embryo development and even leads to lethality. How the epigenomes are inherited, reprogrammed, and reestablished in this critical developmental period has gradually been unveiled through the rapid development of technologies including ultrasensitive chromatin analysis methods. In this review, we summarize the latest findings on epigenetic reprogramming in gametogenesis and embryogenesis, and how it contributes to gamete maturation and parental-to-zygotic transition. Finally, we highlight the key questions that remain to be answered to fully understand chromatin regulation and nuclear reprogramming in early development.
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Affiliation(s)
- Zhenhai Du
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Ke Zhang
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Wei Xie
- Center for Stem Cell Biology and Regenerative Medicine, MOE Key Laboratory of Bioinformatics, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
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6
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Hill SL, Rogan PK, Wang YX, Knoll JHM. Differentially accessible, single copy sequences form contiguous domains along metaphase chromosomes that are conserved among multiple tissues. Mol Cytogenet 2021; 14:49. [PMID: 34670606 PMCID: PMC8527651 DOI: 10.1186/s13039-021-00567-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/08/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND During mitosis, chromatin engages in a dynamic cycle of condensation and decondensation. Condensation into distinct units to ensure high fidelity segregation is followed by rapid and reproducible decondensation to produce functional daughter cells. Factors contributing to the reproducibility of chromatin structure between cell generations are not well understood. We investigated local metaphase chromosome condensation along mitotic chromosomes within genomic intervals showing differential accessibility (DA) between homologs. DA was originally identified using short sequence-defined single copy (sc) DNA probes of < 5 kb in length by fluorescence in situ hybridization (scFISH) in peripheral lymphocytes. These structural differences between metaphase homologs are non-random, stable, and heritable epigenetic marks which have led to the proposed function of DA as a marker of chromatin memory. Here, we characterize the organization of DA intervals into chromosomal domains by identifying multiple DA loci in close proximity to each other and examine the conservation of DA between tissues. RESULTS We evaluated multiple adjacent scFISH probes at 6 different DA loci from chromosomal regions 2p23, 3p24, 12p12, 15q22, 15q24 and 20q13 within peripheral blood T-lymphocytes. DA was organized within domains that extend beyond the defined boundaries of individual scFISH probes. Based on hybridizations of 2 to 4 scFISH probes per domain, domains ranged in length from 16.0 kb to 129.6 kb. Transcriptionally inert chromosomal DA regions in T-lymphocytes also demonstrated conservation of DA in bone marrow and fibroblast cells. CONCLUSIONS We identified novel chromosomal regions with allelic differences in metaphase chromosome accessibility and demonstrated that these accessibility differences appear to be aggregated into contiguous domains extending beyond individual scFISH probes. These domains are encompassed by previously established topologically associated domain (TAD) boundaries. DA appears to be a conserved feature of human metaphase chromosomes across different stages of lymphocyte differentiation and germ cell origin, consistent with its proposed role in maintenance of intergenerational cellular chromosome memory.
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Affiliation(s)
- Seana L Hill
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - Peter K Rogan
- Departments of Biochemistry and Oncology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
- Cytognomix Inc., London, ON, Canada
| | - Yi Xuan Wang
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - Joan H M Knoll
- Department of Pathology & Laboratory Medicine, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.
- Cytognomix Inc., London, ON, Canada.
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7
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Abstract
Dehydration of cells by acute hyperosmotic stress has profound effects upon cell structure and function. Interphase chromatin and mitotic chromosomes collapse ("congelation"). HL-60/S4 cells remain ~100% viable for, at least, 1 hour, exhibiting shrinkage to ~2/3 their original volume, when placed in 300mM sucrose in tissue culture medium. Fixed cells were imaged by immunostaining confocal and STED microscopy. At a "global" structural level (μm), mitotic chromosomes congeal into a residual gel with apparent (phase) separations of Ki67, CTCF, SMC2, RAD21, H1 histones and HMG proteins. At an "intermediate" level (sub-μm), radial distribution analysis of STED images revealed a most probable peak DNA density separation of ~0.16 μm, essentially unchanged by hyperosmotic stress. At a "local" structural level (~1-2 nm), in vivo crosslinking revealed essentially unchanged crosslinked products between H1, HMG and inner histones. Hyperosmotic cellular stress is discussed in terms of concepts of mitotic chromosome structure and liquid-liquid phase separation.
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Affiliation(s)
- Ada L Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, Portland, ME, USA
| | - Travis J Gould
- Department of Physics & Astronomy, Bates College, Lewiston, ME,USA
| | - Logan Boyd
- Department of Physics & Astronomy, Bates College, Lewiston, ME,USA
| | - Bettina Sarg
- Division of Clinical Biochemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Donald E Olins
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New England, Portland, ME, USA
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8
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Pelham-Webb B, Murphy D, Apostolou E. Dynamic 3D Chromatin Reorganization during Establishment and Maintenance of Pluripotency. Stem Cell Reports 2020; 15:1176-1195. [PMID: 33242398 PMCID: PMC7724465 DOI: 10.1016/j.stemcr.2020.10.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/25/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Higher-order chromatin structure is tightly linked to gene expression and therefore cell identity. In recent years, the chromatin landscape of pluripotent stem cells has become better characterized, and unique features at various architectural levels have been revealed. However, the mechanisms that govern establishment and maintenance of these topological characteristics and the temporal and functional relationships with transcriptional or epigenetic features are still areas of intense study. Here, we will discuss progress and limitations of our current understanding regarding how the 3D chromatin topology of pluripotent stem cells is established during somatic cell reprogramming and maintained during cell division. We will also discuss evidence and theories about the driving forces of topological reorganization and the functional links with key features and properties of pluripotent stem cell identity.
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Affiliation(s)
- Bobbie Pelham-Webb
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA
| | - Dylan Murphy
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Effie Apostolou
- Sanford I. Weill Department of Medicine, Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA.
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9
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Wang A, Kolhe JA, Gioacchini N, Baade I, Brieher WM, Peterson CL, Freeman BC. Mechanism of Long-Range Chromosome Motion Triggered by Gene Activation. Dev Cell 2020; 52:309-320.e5. [PMID: 31902656 PMCID: PMC7108666 DOI: 10.1016/j.devcel.2019.12.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 11/18/2019] [Accepted: 12/12/2019] [Indexed: 12/18/2022]
Abstract
Movement of chromosome sites within interphase cells is critical for numerous pathways including RNA transcription and genome organization. Yet, a mechanism for reorganizing chromatin in response to these events had not been reported. Here, we delineate a molecular chaperone-dependent pathway for relocating activated gene loci in yeast. Our presented data support a model in which a two-authentication system mobilizes a gene promoter through a dynamic network of polymeric nuclear actin. Transcription factor-dependent nucleation of a myosin motor propels the gene locus through the actin matrix, and fidelity of the actin association was ensured by ARP-containing chromatin remodelers. Motor activity of nuclear myosin was dependent on the Hsp90 chaperone. Hsp90 further contributed by biasing the remodeler-actin interaction toward nucleosomes with the non-canonical histone H2A.Z, thereby focusing the pathway on select sites such as transcriptionally active genes. Together, the system provides a rapid and effective means to broadly yet selectively mobilize chromatin sites.
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Affiliation(s)
- Anqi Wang
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Janhavi A Kolhe
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Nate Gioacchini
- Program of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Imke Baade
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Craig L Peterson
- Program of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Brian C Freeman
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA.
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10
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Erenpreisa J, Giuliani A. Resolution of Complex Issues in Genome Regulation and Cancer Requires Non-Linear and Network-Based Thermodynamics. Int J Mol Sci 2019; 21:E240. [PMID: 31905791 PMCID: PMC6981914 DOI: 10.3390/ijms21010240] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/22/2019] [Accepted: 12/27/2019] [Indexed: 02/06/2023] Open
Abstract
The apparent lack of success in curing cancer that was evidenced in the last four decades of molecular medicine indicates the need for a global re-thinking both its nature and the biological approaches that we are taking in its solution. The reductionist, one gene/one protein method that has served us well until now, and that still dominates in biomedicine, requires complementation with a more systemic/holistic approach, to address the huge problem of cross-talk between more than 20,000 protein-coding genes, about 100,000 protein types, and the multiple layers of biological organization. In this perspective, the relationship between the chromatin network organization and gene expression regulation plays a fundamental role. The elucidation of such a relationship requires a non-linear thermodynamics approach to these biological systems. This change of perspective is a necessary step for developing successful 'tumour-reversion' therapeutic strategies.
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Affiliation(s)
- Jekaterina Erenpreisa
- Cancer Research Division, Latvian Biomedicine Research and Study Centre, LV1067 Riga, Latvia
| | - Alessandro Giuliani
- Environmental and Health Department, Istituto Superiore di Sanità, 00161 Rome, Italy;
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11
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Wu Y, Cheng Z, Bai Y, Ma X. Epigenetic Mechanisms of Maternal Dietary Protein and Amino Acids Affecting Growth and Development of Offspring. Curr Protein Pept Sci 2019; 20:727-735. [PMID: 30678627 DOI: 10.2174/1389203720666190125110150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 12/30/2018] [Accepted: 01/10/2019] [Indexed: 12/16/2022]
Abstract
Nutrients can regulate metabolic activities of living organisms through epigenetic mechanisms, including DNA methylation, histone modification, and RNA regulation. Since the nutrients required for early embryos and postpartum lactation are derived in whole or in part from maternal and lactating nutrition, the maternal nutritional level affects the growth and development of fetus and creates a profound relationship between disease development and early environmental exposure in the offspring's later life. Protein is one of the most important biological macromolecules, involved in almost every process of life, such as information transmission, energy processing and material metabolism. Maternal protein intake levels may affect the integrity of the fetal genome and alter DNA methylation and gene expression. Most amino acids are supplied to the fetus from the maternal circulation through active transport of placenta. Some amino acids, such as methionine, as dietary methyl donor, play an important role in DNA methylation and body's one-carbon metabolism. The purpose of this review is to describe effects of maternal dietary protein and amino acid intake on fetal and neonatal growth and development through epigenetic mechanisms, with examples in humans and animals.
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Affiliation(s)
- Yi Wu
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Zhibin Cheng
- College of Animal Science and Technology, Yunnan Agricultural University, Kunming, Yunan 650201, China
| | - Yueyu Bai
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.,Animal Health Supervision of Henan province, Breeding Animal Genetic Performance Measurement Center of Henan Province, Zhengzhou, Henan 450008, China.,Henan Institute of Science and Technology, Xinxiang, Henan 453003, China
| | - Xi Ma
- State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.,Department of Internal Medicine, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75230, United States
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12
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Poleshko A, Smith CL, Nguyen SC, Sivaramakrishnan P, Wong KG, Murray JI, Lakadamyali M, Joyce EF, Jain R, Epstein JA. H3K9me2 orchestrates inheritance of spatial positioning of peripheral heterochromatin through mitosis. eLife 2019; 8:49278. [PMID: 31573510 PMCID: PMC6795522 DOI: 10.7554/elife.49278] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/30/2019] [Indexed: 12/16/2022] Open
Abstract
Cell-type-specific 3D organization of the genome is unrecognizable during mitosis. It remains unclear how essential positional information is transmitted through cell division such that a daughter cell recapitulates the spatial genome organization of the parent. Lamina-associated domains (LADs) are regions of repressive heterochromatin positioned at the nuclear periphery that vary by cell type and contribute to cell-specific gene expression and identity. Here we show that histone 3 lysine 9 dimethylation (H3K9me2) is an evolutionarily conserved, specific mark of nuclear peripheral heterochromatin and that it is retained through mitosis. During mitosis, phosphorylation of histone 3 serine 10 temporarily shields the H3K9me2 mark allowing for dissociation of chromatin from the nuclear lamina. Using high-resolution 3D immuno-oligoFISH, we demonstrate that H3K9me2-enriched genomic regions, which are positioned at the nuclear lamina in interphase cells prior to mitosis, re-associate with the forming nuclear lamina before mitotic exit. The H3K9me2 modification of peripheral heterochromatin ensures that positional information is safeguarded through cell division such that individual LADs are re-established at the nuclear periphery in daughter nuclei. Thus, H3K9me2 acts as a 3D architectural mitotic guidepost. Our data establish a mechanism for epigenetic memory and inheritance of spatial organization of the genome.
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Affiliation(s)
- Andrey Poleshko
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Cheryl L Smith
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Son C Nguyen
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Priya Sivaramakrishnan
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Karen G Wong
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - John Isaac Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Eric F Joyce
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Rajan Jain
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Penn Cardiovascular Institute and Institute of Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Jonathan A Epstein
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States.,Penn Cardiovascular Institute and Institute of Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
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13
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Parker MW, Bell M, Mir M, Kao JA, Darzacq X, Botchan MR, Berger JM. A new class of disordered elements controls DNA replication through initiator self-assembly. eLife 2019; 8:e48562. [PMID: 31560342 PMCID: PMC6764820 DOI: 10.7554/elife.48562] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 08/14/2019] [Indexed: 12/11/2022] Open
Abstract
The initiation of DNA replication in metazoans occurs at thousands of chromosomal sites known as origins. At each origin, the Origin Recognition Complex (ORC), Cdc6, and Cdt1 co-assemble to load the Mcm2-7 replicative helicase onto chromatin. Current replication models envisage a linear arrangement of isolated origins functioning autonomously; the extent of inter-origin organization and communication is unknown. Here, we report that the replication initiation machinery of D. melanogaster unexpectedly undergoes liquid-liquid phase separation (LLPS) upon binding DNA in vitro. We find that ORC, Cdc6, and Cdt1 contain intrinsically disordered regions (IDRs) that drive LLPS and constitute a new class of phase separating elements. Initiator IDRs are shown to regulate multiple functions, including chromosome recruitment, initiator-specific co-assembly, and Mcm2-7 loading. These data help explain how CDK activity controls replication initiation and suggest that replication programs are subject to higher-order levels of inter-origin organization.
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Affiliation(s)
- Matthew W Parker
- Department of Biophysics and Biophysical ChemistryJohns Hopkins School of MedicineBaltimoreUnited States
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Maren Bell
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Mustafa Mir
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Jonchee A Kao
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Xavier Darzacq
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - Michael R Botchan
- Department of Molecular and Cell BiologyUniversity of California, BerkeleyBerkeleyUnited States
| | - James M Berger
- Department of Biophysics and Biophysical ChemistryJohns Hopkins School of MedicineBaltimoreUnited States
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14
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Kim JE. Bookmarking by histone methylation ensures chromosomal integrity during mitosis. Arch Pharm Res 2019; 42:466-480. [PMID: 31020544 DOI: 10.1007/s12272-019-01156-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/19/2019] [Indexed: 12/22/2022]
Abstract
The cell cycle is an orchestrated process that replicates DNA and transmits genetic information to daughter cells. Cell cycle progression is governed by diverse histone modifications that control gene transcription in a timely fashion. Histone modifications also regulate cell cycle progression by marking specific chromatic regions. While many reviews have covered histone phosphorylation and acetylation as regulators of the cell cycle, little attention has been paid to the roles of histone methylation in the faithful progression of mitosis. Indeed, specific histone methylations occurring before, during, or after mitosis affect kinetochore assembly and chromosome condensation and segregation. In addition to timing, histone methylations specify the chromatin regions such as chromosome arms, pericentromere, and centromere. Therefore, spatiotemporal programming of histone methylations ensures epigenetic inheritance through mitosis. This review mainly discusses histone methylations and their relevance to mitotic progression.
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Affiliation(s)
- Ja-Eun Kim
- Department of Pharmacology, School of Medicine, Kyung Hee University, Seoul, 02447, Republic of Korea.
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15
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Fritz AJ, Gillis NE, Gerrard DL, Rodriguez PD, Hong D, Rose JT, Ghule PN, Bolf EL, Gordon JA, Tye CE, Boyd JR, Tracy KM, Nickerson JA, van Wijnen AJ, Imbalzano AN, Heath JL, Frietze SE, Zaidi SK, Carr FE, Lian JB, Stein JL, Stein GS. Higher order genomic organization and epigenetic control maintain cellular identity and prevent breast cancer. Genes Chromosomes Cancer 2019; 58:484-499. [PMID: 30873710 DOI: 10.1002/gcc.22731] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 12/24/2022] Open
Abstract
Cells establish and sustain structural and functional integrity of the genome to support cellular identity and prevent malignant transformation. In this review, we present a strategic overview of epigenetic regulatory mechanisms including histone modifications and higher order chromatin organization (HCO) that are perturbed in breast cancer onset and progression. Implications for dysfunctions that occur in hormone regulation, cell cycle control, and mitotic bookmarking in breast cancer are considered, with an emphasis on epithelial-to-mesenchymal transition and cancer stem cell activities. The architectural organization of regulatory machinery is addressed within the contexts of translating cancer-compromised genomic organization to advances in breast cancer risk assessment, diagnosis, prognosis, and identification of novel therapeutic targets with high specificity and minimal off target effects.
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Affiliation(s)
- A J Fritz
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - N E Gillis
- University of Vermont Cancer Center, Burlington, Vermont.,Department of Pharmacology, Larner college of Medicine, University of Vermont, Burlington, Vermont
| | - D L Gerrard
- Cellular Molecular Biomedical Sciences Program, University of Vermont, Burlington, Vermont.,Department of Biomedical and Health Sciences, University of Vermont, Burlington, Vermont
| | - P D Rodriguez
- Cellular Molecular Biomedical Sciences Program, University of Vermont, Burlington, Vermont.,Department of Biomedical and Health Sciences, University of Vermont, Burlington, Vermont
| | - D Hong
- Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts
| | - J T Rose
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - P N Ghule
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - E L Bolf
- University of Vermont Cancer Center, Burlington, Vermont.,Department of Pharmacology, Larner college of Medicine, University of Vermont, Burlington, Vermont
| | - J A Gordon
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - C E Tye
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - J R Boyd
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - K M Tracy
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - J A Nickerson
- Division of Genes and Development of the Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts
| | - A J van Wijnen
- Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic Minnesota, Rochester, Minnesota
| | - A N Imbalzano
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - J L Heath
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont.,Department of Pediatrics, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - S E Frietze
- Cellular Molecular Biomedical Sciences Program, University of Vermont, Burlington, Vermont.,Department of Biomedical and Health Sciences, University of Vermont, Burlington, Vermont
| | - S K Zaidi
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - F E Carr
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont.,Department of Pharmacology, Larner college of Medicine, University of Vermont, Burlington, Vermont
| | - J B Lian
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - J L Stein
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
| | - G S Stein
- Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont.,University of Vermont Cancer Center, Burlington, Vermont
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16
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Oomen ME, Hansen AS, Liu Y, Darzacq X, Dekker J. CTCF sites display cell cycle-dependent dynamics in factor binding and nucleosome positioning. Genome Res 2019; 29:236-249. [PMID: 30655336 PMCID: PMC6360813 DOI: 10.1101/gr.241547.118] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/15/2018] [Indexed: 12/28/2022]
Abstract
CCCTC-binding factor (CTCF) plays a key role in the formation of topologically associating domains (TADs) and loops in interphase. During mitosis TADs are absent, but how TAD formation is dynamically controlled during the cell cycle is not known. Several contradicting observations have been made regarding CTCF binding to mitotic chromatin using both genomics- and microscopy-based techniques. Here, we have used four different assays to address this debate. First, using 5C, we confirmed that TADs and CTCF loops are readily detected in interphase, but absent during prometaphase. Second, ATAC-seq analysis showed that CTCF sites display greatly reduced accessibility and lose the CTCF footprint in prometaphase, suggesting loss of CTCF binding and rearrangement of the nucleosomal array around the binding motif. In contrast, transcription start sites remain accessible in prometaphase, although adjacent nucleosomes can also become repositioned and occupy at least a subset of start sites during mitosis. Third, loss of site-specific CTCF binding was directly demonstrated using CUT&RUN. Histone modifications and histone variants are maintained in mitosis, suggesting a role in bookmarking of active CTCF sites. Finally, live-cell imaging, fluorescence recovery after photobleaching, and single molecule tracking showed that almost all CTCF chromatin binding is lost in prometaphase. Combined, our results demonstrate loss of CTCF binding to CTCF sites during prometaphase and rearrangement of the chromatin landscape around CTCF motifs. This, combined with loss of cohesin, would contribute to the observed loss of TADs and CTCF loops during mitosis and reveals that CTCF sites, key architectural cis-elements, display cell cycle stage–dependent dynamics in factor binding and nucleosome positioning.
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Affiliation(s)
- Marlies E Oomen
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Anders S Hansen
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, California 94720, USA
| | - Yu Liu
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, Li Ka Shing Center for Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley, California 94720, USA
| | - Job Dekker
- Program in Systems Biology, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
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17
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Biggs R, Liu PZ, Stephens AD, Marko JF. Effects of altering histone posttranslational modifications on mitotic chromosome structure and mechanics. Mol Biol Cell 2019; 30:820-827. [PMID: 30625026 PMCID: PMC6589789 DOI: 10.1091/mbc.e18-09-0592] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
During cell division, chromatin is compacted into mitotic chromosomes to aid faithful segregation of the genome between two daughter cells. Posttranslational modifications (PTMs) of histones alter compaction of interphase chromatin, but it remains poorly understood how these modifications affect mitotic chromosome stiffness and structure. Using micropipette-based force measurements and epigenetic drugs, we probed the influence of canonical histone PTMs that dictate interphase euchromatin (acetylation) and heterochromatin (methylation) on mitotic chromosome stiffness. By measuring chromosome doubling force (the force required to double chromosome length), we find that histone methylation, but not acetylation, contributes to mitotic structure and stiffness. We discuss our findings in the context of chromatin gel modeling of the large-scale organization of mitotic chromosomes.
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Affiliation(s)
- Ronald Biggs
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Patrick Z Liu
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - Andrew D Stephens
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208
| | - John F Marko
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208.,Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
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18
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Bellec M, Radulescu O, Lagha M. Remembering the past: Mitotic bookmarking in a developing embryo. ACTA ACUST UNITED AC 2018; 11:41-49. [PMID: 30417158 PMCID: PMC6218673 DOI: 10.1016/j.coisb.2018.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During development, transcriptional properties of progenitor cells are stably propagated across multiple cellular divisions. Yet, at each division, chromatin faces structural constraints imposed by the important nuclear re-organization operating during mitosis. It is now clear that not all transcriptional regulators are ejected during mitosis, but rather that a subset of transcription factors, chromatin regulators and epigenetic histone marks are able to ‘bookmark’ specific loci, thereby providing a mitotic memory. Here we review mechanisms of mitotic bookmarking and discuss their impact on transcriptional dynamics in the context of multicellular developing embryos. We document recent discoveries and technological advances, and present current mathematical models of short-term transcriptional memory. Mitotically retained factors are able to ‘bookmark’ specific loci during embryogenesis. Mitotic bookmarking can elicit rapid post-mitotic transcriptional re-activation. Mathematical models relating transcriptional memory predict that efficient memory requires slow dynamics. Mitotic memory leads to a spectrum of consequences: stability, flexibility or plasticity.
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Affiliation(s)
- Maelle Bellec
- Institut de Genetique Moleculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
| | - Ovidiu Radulescu
- DIMNP, UMR CNRS 5235, University of Montpellier, Montpellier, France
| | - Mounia Lagha
- Institut de Genetique Moleculaire de Montpellier, University of Montpellier, CNRS, Montpellier, France
- Corresponding author: Lagha, Mounia
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19
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Yang S, Zhao N, Yang Y, Hu Y, Dong H, Zhao R. Mitotically Stable Modification of DNA Methylation in IGF2/H19 Imprinting Control Region Is Associated with Activated Hepatic IGF2 Expression in Offspring Rats from Betaine-Supplemented Dams. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:2704-2713. [PMID: 29376352 DOI: 10.1021/acs.jafc.7b05418] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The growth-promoting action of betaine involves activation of GH/IGF-1 signaling, yet it remains unclear whether insulin-like growth factor 2 (IGF2), an imprinting gene, is affected by maternal dietary betaine supplementation. In this study, F1 offspring rats derived from dams fed basal or betaine-supplemented diet were examined at D21 and D63. Maternal betaine significantly upregulated the hepatic expression of IGF2 mRNA and protein in offspring rats at both D21 and D63, which was accompanied by enhanced hepatic IGF2 immunoreactivity and elevated serum IGF-2 level. Higher protein expression of betaine-homocysteine methyltransferase and DNA methyltransferase 1 was detected in the betaine group at D21, but not D63. However, hypermethylation of the imprinting control region of the IGF2/H19 locus at D21 was maintained at D63. These results indicate that maternal betaine modifies DNA methylation of IGF2/H19 imprinting control region in a mitotically stable fasion, which was associated with the activation hepatic IGF2 expression in offspring rats.
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Affiliation(s)
- Shu Yang
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing 210095 , P. R. China
- Key Laboratory of Animal Physiology & Biochemistry , Nanjing Agricultural University , Nanjing 210095 , P. R. China
| | - Nannan Zhao
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing 210095 , P. R. China
- Key Laboratory of Animal Physiology & Biochemistry , Nanjing Agricultural University , Nanjing 210095 , P. R. China
| | - Yang Yang
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing 210095 , P. R. China
- Key Laboratory of Animal Physiology & Biochemistry , Nanjing Agricultural University , Nanjing 210095 , P. R. China
| | - Yun Hu
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing 210095 , P. R. China
- Key Laboratory of Animal Physiology & Biochemistry , Nanjing Agricultural University , Nanjing 210095 , P. R. China
| | - Haibo Dong
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing 210095 , P. R. China
- Key Laboratory of Animal Physiology & Biochemistry , Nanjing Agricultural University , Nanjing 210095 , P. R. China
| | - Ruqian Zhao
- MOE Joint International Research Laboratory of Animal Health & Food Safety , Nanjing Agricultural University , Nanjing 210095 , P. R. China
- Key Laboratory of Animal Physiology & Biochemistry , Nanjing Agricultural University , Nanjing 210095 , P. R. China
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20
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Modes of Interaction of KMT2 Histone H3 Lysine 4 Methyltransferase/COMPASS Complexes with Chromatin. Cells 2018; 7:cells7030017. [PMID: 29498679 PMCID: PMC5870349 DOI: 10.3390/cells7030017] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/22/2018] [Accepted: 02/27/2018] [Indexed: 02/07/2023] Open
Abstract
Regulation of gene expression is achieved by sequence-specific transcriptional regulators, which convey the information that is contained in the sequence of DNA into RNA polymerase activity. This is achieved by the recruitment of transcriptional co-factors. One of the consequences of co-factor recruitment is the control of specific properties of nucleosomes, the basic units of chromatin, and their protein components, the core histones. The main principles are to regulate the position and the characteristics of nucleosomes. The latter includes modulating the composition of core histones and their variants that are integrated into nucleosomes, and the post-translational modification of these histones referred to as histone marks. One of these marks is the methylation of lysine 4 of the core histone H3 (H3K4). While mono-methylation of H3K4 (H3K4me1) is located preferentially at active enhancers, tri-methylation (H3K4me3) is a mark found at open and potentially active promoters. Thus, H3K4 methylation is typically associated with gene transcription. The class 2 lysine methyltransferases (KMTs) are the main enzymes that methylate H3K4. KMT2 enzymes function in complexes that contain a necessary core complex composed of WDR5, RBBP5, ASH2L, and DPY30, the so-called WRAD complex. Here we discuss recent findings that try to elucidate the important question of how KMT2 complexes are recruited to specific sites on chromatin. This is embedded into short overviews of the biological functions of KMT2 complexes and the consequences of H3K4 methylation.
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21
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Maizels Y, Elbaz A, Hernandez-Vicens R, Sandrusy O, Rosenberg A, Gerlitz G. Increased chromatin plasticity supports enhanced metastatic potential of mouse melanoma cells. Exp Cell Res 2017; 357:282-290. [PMID: 28551377 DOI: 10.1016/j.yexcr.2017.05.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 12/17/2022]
Abstract
Metastasis formation is strongly dependent on the migration capabilities of tumor cells. Recently it has become apparent that nuclear structure and morphology affect the cellular ability to migrate. Previously we found that migration of melanoma cells is both associated with and dependent on global chromatin condensation. Therefore, we anticipated that tumor progression would be associated with increased chromatin condensation. Interestingly, the opposite has been reported for melanoma. In trying to resolve this contradiction, we show that during growth conditions, tumor progression is associated with global chromatin de-condensation that is beneficial for faster proliferation. However, upon induction of migration, in both low- and high-metastatic mouse melanoma cells chromatin undergoes condensation to support cell migration. Our results reveal that throughout tumor progression induction of chromatin condensation by migration signals is maintained, whereas the organization of chromatin during growth conditions is altered. Thus, tumor progression is associated with an increase in chromatin dynamics.
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Affiliation(s)
- Yael Maizels
- Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Israel
| | - Adi Elbaz
- Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Israel
| | | | - Oshrat Sandrusy
- Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Israel
| | - Anna Rosenberg
- Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Israel
| | - Gabi Gerlitz
- Department of Molecular Biology, Faculty of Life Sciences, Ariel University, Israel.
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