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Melkus G, Sizovs A, Rucevskis P, Silina S. Transcriptional Hubs Within Cliques in Ensemble Hi-C Chromatin Interaction Networks. J Comput Biol 2024; 31:589-596. [PMID: 38768423 DOI: 10.1089/cmb.2024.0515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024] Open
Abstract
Chromatin conformation capture technologies permit the study of chromatin spatial organization on a genome-wide scale at a variety of resolutions. Despite the increasing precision and resolution of high-throughput chromatin conformation capture (Hi-C) methods, it remains challenging to conclusively link transcriptional activity to spatial organizational phenomena. We have developed a clique-based approach for analyzing Hi-C data that helps identify chromosomal hotspots that feature considerable enrichment of chromatin annotations for transcriptional start sites and, building on previously published work, show that these chromosomal hotspots are not only significantly enriched in RNA polymerase II binding sites as identified by the ENCODE project, but also identify a noticeable increase in FANTOM5 and GTEx transcription within our identified cliques across a variety of tissue types. From the obtained data, we surmise that our cliques are a suitable method for identifying transcription factories in Hi-C data, and outline further extensions to the method that may make it useful for locating regions of increased transcriptional activity in datasets where in-depth expression or polymerase data may not be available.
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Affiliation(s)
- Gatis Melkus
- Institute of Mathematics and Computer Science, University of Latvia, Riga, Latvia
| | - Andrejs Sizovs
- Institute of Mathematics and Computer Science, University of Latvia, Riga, Latvia
| | - Peteris Rucevskis
- Institute of Mathematics and Computer Science, University of Latvia, Riga, Latvia
| | - Sandra Silina
- Institute of Mathematics and Computer Science, University of Latvia, Riga, Latvia
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2
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Camerino M, Chang W, Cvekl A. Analysis of long-range chromatin contacts, compartments and looping between mouse embryonic stem cells, lens epithelium and lens fibers. Epigenetics Chromatin 2024; 17:10. [PMID: 38643244 PMCID: PMC11031936 DOI: 10.1186/s13072-024-00533-x] [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: 11/15/2023] [Accepted: 03/08/2024] [Indexed: 04/22/2024] Open
Abstract
BACKGROUND Nuclear organization of interphase chromosomes involves individual chromosome territories, "open" and "closed" chromatin compartments, topologically associated domains (TADs) and chromatin loops. The DNA- and RNA-binding transcription factor CTCF together with the cohesin complex serve as major organizers of chromatin architecture. Cellular differentiation is driven by temporally and spatially coordinated gene expression that requires chromatin changes of individual loci of various complexities. Lens differentiation represents an advantageous system to probe transcriptional mechanisms underlying tissue-specific gene expression including high transcriptional outputs of individual crystallin genes until the mature lens fiber cells degrade their nuclei. RESULTS Chromatin organization between mouse embryonic stem (ES) cells, newborn (P0.5) lens epithelium and fiber cells were analyzed using Hi-C. Localization of CTCF in both lens chromatins was determined by ChIP-seq and compared with ES cells. Quantitative analyses show major differences between number and size of TADs and chromatin loop size between these three cell types. In depth analyses show similarities between lens samples exemplified by overlaps between compartments A and B. Lens epithelium-specific CTCF peaks are found in mostly methylated genomic regions while lens fiber-specific and shared peaks occur mostly within unmethylated DNA regions. Major differences in TADs and loops are illustrated at the ~ 500 kb Pax6 locus, encoding the critical lens regulatory transcription factor and within a larger ~ 15 Mb WAGR locus, containing Pax6 and other loci linked to human congenital diseases. Lens and ES cell Hi-C data (TADs and loops) together with ATAC-seq, CTCF, H3K27ac, H3K27me3 and ENCODE cis-regulatory sites are shown in detail for the Pax6, Sox1 and Hif1a loci, multiple crystallin genes and other important loci required for lens morphogenesis. The majority of crystallin loci are marked by unexpectedly high CTCF-binding across their transcribed regions. CONCLUSIONS Our study has generated the first data on 3-dimensional (3D) nuclear organization in lens epithelium and lens fibers and directly compared these data with ES cells. These findings generate novel insights into lens-specific transcriptional gene control, open new research avenues to study transcriptional condensates in lens fiber cells, and enable studies of non-coding genetic variants linked to cataract and other lens and ocular abnormalities.
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Affiliation(s)
- Michael Camerino
- The Departments Genetics, Albert Einstein College of Medicine, NY10461, Bronx, USA
| | - William Chang
- Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY10461, Bronx, USA
| | - Ales Cvekl
- The Departments Genetics, Albert Einstein College of Medicine, NY10461, Bronx, USA.
- Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY10461, Bronx, USA.
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3
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Mañes-García J, Marco-Ferreres R, Beccari L. Shaping gene expression and its evolution by chromatin architecture and enhancer activity. Curr Top Dev Biol 2024; 159:406-437. [PMID: 38729683 DOI: 10.1016/bs.ctdb.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Transcriptional regulation plays a pivotal role in orchestrating the intricate genetic programs governing embryonic development. The expression of developmental genes relies on the combined activity of several cis-regulatory elements (CREs), such as enhancers and silencers, which can be located at long linear distances from the genes that they regulate and that interact with them through establishment of chromatin loops. Mutations affecting their activity or interaction with their target genes can lead to developmental disorders and are thought to have importantly contributed to the evolution of the animal body plan. The income of next-generation-sequencing approaches has allowed identifying over a million of sequences with putative regulatory potential in the human genome. Characterizing their function and establishing gene-CREs maps is essential to decode the logic governing developmental gene expression and is one of the major challenges of the post-genomic era. Chromatin 3D organization plays an essential role in determining how CREs specifically contact their target genes while avoiding deleterious off-target interactions. Our understanding of these aspects has greatly advanced with the income of chromatin conformation capture techniques and fluorescence microscopy approaches to visualize the organization of DNA elements in the nucleus. Here we will summarize relevant aspects of how the interplay between CRE activity and chromatin 3D organization regulates developmental gene expression and how it relates to pathological conditions and the evolution of animal body plan.
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Affiliation(s)
| | | | - Leonardo Beccari
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain.
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Qu Z, Batz Z, Singh N, Marchal C, Swaroop A. Stage-specific dynamic reorganization of genome topology shapes transcriptional neighborhoods in developing human retinal organoids. Cell Rep 2023; 42:113543. [PMID: 38048222 PMCID: PMC10790351 DOI: 10.1016/j.celrep.2023.113543] [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: 05/12/2023] [Revised: 09/21/2023] [Accepted: 11/17/2023] [Indexed: 12/06/2023] Open
Abstract
We have generated a high-resolution Hi-C map of developing human retinal organoids to elucidate spatiotemporal dynamics of genomic architecture and its relationship with gene expression patterns. We demonstrate progressive stage-specific alterations in DNA topology and correlate these changes with transcription of cell-type-restricted gene markers during retinal differentiation. Temporal Hi-C reveals a shift toward A compartment for protein-coding genes and B compartment for non-coding RNAs, displaying high and low expression, respectively. Notably, retina-enriched genes are clustered near lost boundaries of topologically associated domains (TADs), and higher-order assemblages (i.e., TAD cliques) localize in active chromatin regions with binding sites for eye-field transcription factors. These genes gain chromatin contacts at their transcription start site as organoid differentiation proceeds. Our study provides a global view of chromatin architecture dynamics associated with diversification of cell types during retinal development and serves as a foundational resource for in-depth functional investigations of retinal developmental traits.
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Affiliation(s)
- Zepeng Qu
- Neurobiology, Neurodegeneration, and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Zachary Batz
- Neurobiology, Neurodegeneration, and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Nivedita Singh
- Neurobiology, Neurodegeneration, and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA
| | - Claire Marchal
- Neurobiology, Neurodegeneration, and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA; In silichrom Ltd, 15 Digby Road, Newbury RG14 1TS, UK
| | - Anand Swaroop
- Neurobiology, Neurodegeneration, and Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892, USA.
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5
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Tolokh IS, Kinney NA, Sharakhov IV, Onufriev AV. Strong interactions between highly dynamic lamina-associated domains and the nuclear envelope stabilize the 3D architecture of Drosophila interphase chromatin. Epigenetics Chromatin 2023; 16:21. [PMID: 37254161 PMCID: PMC10228000 DOI: 10.1186/s13072-023-00492-9] [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: 01/19/2023] [Accepted: 05/04/2023] [Indexed: 06/01/2023] Open
Abstract
BACKGROUND Interactions among topologically associating domains (TADs), and between the nuclear envelope (NE) and lamina-associated domains (LADs) are expected to shape various aspects of three-dimensional (3D) chromatin structure and dynamics; however, relevant genome-wide experiments that may provide statistically significant conclusions remain difficult. RESULTS We have developed a coarse-grained dynamical model of D. melanogaster nuclei at TAD resolution that explicitly accounts for four distinct epigenetic classes of TADs and LAD-NE interactions. The model is parameterized to reproduce the experimental Hi-C map of the wild type (WT) nuclei; it describes time evolution of the chromatin over the G1 phase of the interphase. The simulations include an ensemble of nuclei, corresponding to the experimentally observed set of several possible mutual arrangements of chromosomal arms. The model is validated against multiple structural features of chromatin from several different experiments not used in model development. Predicted positioning of all LADs at the NE is highly dynamic-the same LAD can attach, detach and move far away from the NE multiple times during interphase. The probabilities of LADs to be in contact with the NE vary by an order of magnitude, despite all having the same affinity to the NE in the model. These probabilities are mostly determined by a highly variable local linear density of LADs along the genome, which also has the same strong effect on the predicted positioning of individual TADs -- higher probability of a TAD to be near NE is largely determined by a higher linear density of LADs surrounding this TAD. The distribution of LADs along the chromosome chains plays a notable role in maintaining a non-random average global structure of chromatin. Relatively high affinity of LADs to the NE in the WT nuclei substantially reduces sensitivity of the global radial chromatin distribution to variations in the strength of TAD-TAD interactions compared to the lamin depleted nuclei, where a small (0.5 kT) increase of cross-type TAD-TAD interactions doubles the chromatin density in the central nucleus region. CONCLUSIONS A dynamical model of the entire fruit fly genome makes multiple genome-wide predictions of biological interest. The distribution of LADs along the chromatin chains affects their probabilities to be in contact with the NE and radial positioning of highly mobile TADs, playing a notable role in creating a non-random average global structure of the chromatin. We conjecture that an important role of attractive LAD-NE interactions is to stabilize global chromatin structure against inevitable cell-to-cell variations in TAD-TAD interactions.
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Affiliation(s)
- Igor S. Tolokh
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061 USA
| | - Nicholas Allen Kinney
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061 USA
- Department of Entomology, Virginia Tech, Blacksburg, VA 24061 USA
- Edward Via College of Osteopathic Medicine, 2265 Kraft Drive, Blacksburg, VA 24060 USA
| | | | - Alexey V. Onufriev
- Department of Computer Science, Virginia Tech, Blacksburg, VA 24061 USA
- Department of Physics, Virginia Tech, Blacksburg, VA 24061 USA
- Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA 24061 USA
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6
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Dhall JK, Kasturacharya N, Pandit A, Cp L. Optimized protocol for assay for transposase-accessible chromatin by sequencing (ATAC-seq) from Drosophila melanogaster brain tissue. STAR Protoc 2023; 4:102153. [PMID: 37074906 PMCID: PMC10148076 DOI: 10.1016/j.xpro.2023.102153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/11/2023] [Accepted: 02/13/2023] [Indexed: 04/20/2023] Open
Abstract
Transposase-accessible chromatin by sequencing (ATAC-seq) has emerged as an advantageous technique to assess chromatin accessibility owing to the robustness of "tagmentation" process and a relatively faster library preparation. A comprehensive ATAC-seq protocol from Drosophila brain tissue is currently unavailable. Here, we have provided a detailed protocol of ATAC-seq assay from Drosophila brain tissue. Starting from dissection and transposition to amplification of libraries has been elaborated. Furthermore, a robust ATAC-seq analysis pipeline has been presented. The protocol can be easily adapted for other soft tissues.
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Affiliation(s)
- Jasmine Kaur Dhall
- National Centre for Biological Sciences, TIFR, Bellary Road, Bengaluru 560065, India.
| | - Nandashree Kasturacharya
- National Centre for Biological Sciences, TIFR, Bellary Road, Bengaluru 560065, India; The University of Trans-Disciplinary Health Sciences and Technology (TDU), Bengaluru 560064, India
| | - Awadhesh Pandit
- National Centre for Biological Sciences, TIFR, Bellary Road, Bengaluru 560065, India.
| | - Lakshminarayanan Cp
- National Centre for Biological Sciences, TIFR, Bellary Road, Bengaluru 560065, India
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Song Y, Soto J, Chen B, Hoffman T, Zhao W, Zhu N, Peng Q, Liu L, Ly C, Wong PK, Wang Y, Rowat AC, Kurdistani SK, Li S. Transient nuclear deformation primes epigenetic state and promotes cell reprogramming. NATURE MATERIALS 2022; 21:1191-1199. [PMID: 35927431 PMCID: PMC9529815 DOI: 10.1038/s41563-022-01312-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 06/14/2022] [Indexed: 05/22/2023]
Abstract
Cell reprogramming has wide applications in tissue regeneration, disease modelling and personalized medicine. In addition to biochemical cues, mechanical forces also contribute to the modulation of the epigenetic state and a variety of cell functions through distinct mechanisms that are not fully understood. Here we show that millisecond deformation of the cell nucleus caused by confinement into microfluidic channels results in wrinkling and transient disassembly of the nuclear lamina, local detachment of lamina-associated domains in chromatin and a decrease of histone methylation (histone H3 lysine 9 trimethylation) and DNA methylation. These global changes in chromatin at the early stage of cell reprogramming boost the conversion of fibroblasts into neurons and can be partially reproduced by inhibition of histone H3 lysine 9 and DNA methylation. This mechanopriming approach also triggers macrophage reprogramming into neurons and fibroblast conversion into induced pluripotent stem cells, being thus a promising mechanically based epigenetic state modulation method for cell engineering.
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Affiliation(s)
- Yang Song
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Jennifer Soto
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Binru Chen
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Tyler Hoffman
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Weikang Zhao
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Ninghao Zhu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Qin Peng
- Department of Bioengineering, University of California San Diego, San Diego, CA, USA
| | - Longwei Liu
- Department of Bioengineering, University of California San Diego, San Diego, CA, USA
| | - Chau Ly
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Pak Kin Wong
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Yingxiao Wang
- Department of Bioengineering, University of California San Diego, San Diego, CA, USA
| | - Amy C Rowat
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
- Department of Integrative Biology & Physiology, University of California Los Angeles, Los Angeles, CA, USA
| | - Siavash K Kurdistani
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA
| | - Song Li
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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8
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Maslova A, Krasikova A. FISH Going Meso-Scale: A Microscopic Search for Chromatin Domains. Front Cell Dev Biol 2021; 9:753097. [PMID: 34805161 PMCID: PMC8597843 DOI: 10.3389/fcell.2021.753097] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/08/2021] [Indexed: 12/14/2022] Open
Abstract
The intimate relationships between genome structure and function direct efforts toward deciphering three-dimensional chromatin organization within the interphase nuclei at different genomic length scales. For decades, major insights into chromatin structure at the level of large-scale euchromatin and heterochromatin compartments, chromosome territories, and subchromosomal regions resulted from the evolution of light microscopy and fluorescence in situ hybridization. Studies of nanoscale nucleosomal chromatin organization benefited from a variety of electron microscopy techniques. Recent breakthroughs in the investigation of mesoscale chromatin structures have emerged from chromatin conformation capture methods (C-methods). Chromatin has been found to form hierarchical domains with high frequency of local interactions from loop domains to topologically associating domains and compartments. During the last decade, advances in super-resolution light microscopy made these levels of chromatin folding amenable for microscopic examination. Here we are reviewing recent developments in FISH-based approaches for detection, quantitative measurements, and validation of contact chromatin domains deduced from C-based data. We specifically focus on the design and application of Oligopaint probes, which marked the latest progress in the imaging of chromatin domains. Vivid examples of chromatin domain FISH-visualization by means of conventional, super-resolution light and electron microscopy in different model organisms are provided.
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Affiliation(s)
| | - Alla Krasikova
- Laboratory of Nuclear Structure and Dynamics, Cytology and Histology Department, Saint Petersburg State University, Saint Petersburg, Russia
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Trigiante G, Blanes Ruiz N, Cerase A. Emerging Roles of Repetitive and Repeat-Containing RNA in Nuclear and Chromatin Organization and Gene Expression. Front Cell Dev Biol 2021; 9:735527. [PMID: 34722514 PMCID: PMC8552494 DOI: 10.3389/fcell.2021.735527] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/09/2021] [Indexed: 12/14/2022] Open
Abstract
Genomic repeats have been intensely studied as regulatory elements controlling gene transcription, splicing and genome architecture. Our understanding of the role of the repetitive RNA such as the RNA coming from genomic repeats, or repetitive sequences embedded in mRNA/lncRNAs, in nuclear and cellular functions is instead still limited. In this review we discuss evidence supporting the multifaceted roles of repetitive RNA and RNA binding proteins in nuclear organization, gene regulation, and in the formation of dynamic membrane-less aggregates. We hope that our review will further stimulate research in the consolidating field of repetitive RNA biology.
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Affiliation(s)
| | | | - Andrea Cerase
- Centre for Genomics and Child Health, Barts and The London School of Medicine and Dentistry, Blizard Institute, Queen Mary University of London, London, United Kingdom
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10
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Strickfaden H. Reflections on the organization and the physical state of chromatin in eukaryotic cells. Genome 2020; 64:311-325. [PMID: 33306433 DOI: 10.1139/gen-2020-0132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In recent years, our perception of chromatin structure and organization in the cell nucleus has changed in fundamental ways. The 30 nm chromatin fiber has lost its status as an essential in vivo structure. Hi-C and related biochemical methods, advanced electron and super-resolved fluorescence microscopy, together with concepts from soft matter physics, have revolutionized the field. A comprehensive understanding of the structural and functional interactions that regulate cell cycle and cell type specific nuclear functions appears within reach, but it requires the integration of top-down and bottom-up approachs. In this review, I present an update on nuclear architecture studies with an emphasis on organization and the controversy regarding the physical state of chromatin in cells.
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Affiliation(s)
- Hilmar Strickfaden
- Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
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Peng AYT, Kolhe JA, Behrens LD, Freeman BC. Genome organization: Tag it, move it, place it. Curr Opin Cell Biol 2020; 68:90-97. [PMID: 33166737 DOI: 10.1016/j.ceb.2020.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/28/2020] [Accepted: 10/08/2020] [Indexed: 12/14/2022]
Abstract
Chromosomes are selectively organized within the nuclei of interphase cells reflecting the current fate of each cell and are reorganized in response to various physiological cues to maintain homeostasis. Although substantial progress is being made to establish the various patterns of genome architecture, less is understood on how chromosome folding/positioning is achieved. Here, we discuss recent insights into the cellular mechanisms dictating chromatin movements including the use of epigenetic modifications and allosterically regulated transcription factors, as well as a nucleoskeleton system comprised of actin, myosin, and actin-binding proteins. Together, these nuclear factors help coordinate the positioning of both general and cell-specific genomic architectural features.
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Affiliation(s)
- Audrey Yi Tyan Peng
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA
| | - Janhavi A Kolhe
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA
| | - Lindsey D Behrens
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA
| | - Brian C Freeman
- University of Illinois, Urbana-Champaign, Department of Cell and Developmental Biology, Urbana, IL, 61801, USA.
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12
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van Schaik T, Vos M, Peric-Hupkes D, Hn Celie P, van Steensel B. Cell cycle dynamics of lamina-associated DNA. EMBO Rep 2020; 21:e50636. [PMID: 32893442 PMCID: PMC7645246 DOI: 10.15252/embr.202050636] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
In mammalian interphase nuclei, more than one thousand large genomic regions are positioned at the nuclear lamina (NL). These lamina‐associated domains (LADs) are involved in gene regulation and may provide a backbone for the folding of interphase chromosomes. Little is known about the dynamics of LADs during interphase, in particular at the onset of G1 phase and during DNA replication. We developed an antibody‐based variant of the DamID technology (named pA‐DamID) that allows us to map and visualize genome–NL interactions with high temporal resolution. Application of pA‐DamID combined with synchronization and cell sorting experiments reveals that LAD–NL contacts are generally rapidly established early in G1 phase. However, LADs on the distal ~25 Mb of most chromosomes tend to contact the NL first and then gradually detach, while centromere‐proximal LADs accumulate gradually at the NL. Furthermore, our data indicate that S‐phase chromatin shows transiently increased lamin interactions. These findings highlight a dynamic choreography of LAD–NL contacts during interphase progression and illustrate the usefulness of pA‐DamID to study the dynamics of genome compartmentalization.
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Affiliation(s)
- Tom van Schaik
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Mabel Vos
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Daan Peric-Hupkes
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Patrick Hn Celie
- Protein Facility, Oncode Institute, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, The Netherlands.,Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
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Konkova MS, Ershova ES, Savinova EA, Malinovskaya EM, Shmarina GV, Martynov AV, Veiko RV, Zakharova NV, Umriukhin P, Kostyuk GP, Izhevskaya VL, Kutsev SI, Veiko NN, Kostyuk SV. 1Q12 Loci Movement in the Interphase Nucleus Under the Action of ROS Is an Important Component of the Mechanism That Determines Copy Number Variation of Satellite III (1q12) in Health and Schizophrenia. Front Cell Dev Biol 2020; 8:386. [PMID: 32714923 PMCID: PMC7346584 DOI: 10.3389/fcell.2020.00386] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022] Open
Abstract
Introduction: Genome repeat cluster sizes can affect the chromatin spatial configuration and function. Low-dose ionizing radiation (IR) induces an adaptive response (AR) in human cells. AR includes the change in chromatin spatial configuration that is necessary to change the expression profile of the genome in response to stress. The 1q12 heterochromatin loci movement from the periphery to the center of the nucleus is a marker of the chromatin configuration change. We hypothesized that a large 1q12 domain could affect chromatin movement, thereby inhibiting the AR. Materials and Methods: 2D fluorescent in situ hybridization (FISH) method was used for the satellite III fragment from the 1q12 region (f-SatIII) localization analysis in the interphase nuclei of healthy control (HC) lymphocytes, schizophrenia (SZ) patients, and in cultured mesenchymal stem cells (MSCs). The localization of the nucleolus was analyzed by the nucleolus Ag staining. The non-radioactive quantitative hybridization (NQH) technique was used for the f-SatIII fragment content in DNA analysis. Satellite III fragments transcription was analyzed by reverse transcriptase quantitative PCR (RT-qPCR). Results: Low-dose IR induces the small-area 1q12 domains movement from the periphery to the central regions of the nucleus in HC lymphocytes and MSCs. Simultaneously, nucleolus moves from the nucleus center toward the nuclear envelope. The nucleolus in that period increases. The distance between the 1q12 domain and the nucleolus in irradiated cells is significantly reduced. The large-area 1q12 domains do not move in response to stress. During prolonged cultivation, the irradiated cells with a large f-SatIII amount die, and the population is enriched with the cells with low f-SatIII content. IR induces satellite III transcription in HC lymphocytes. Intact SZ patients' lymphocytes have the same signs of nuclei activation as irradiated HC cells. Conclusion: When a cell population responds to stress, cells are selected according to the size of the 1q12 domain (the f-SatIII content). The low content of the f-SatIII repeat in SZ patients may be a consequence of the chronic oxidative stress and of a large copies number of the ribosomal repeats.
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Affiliation(s)
- Marina Sergeevna Konkova
- Federal State Budgetary Scientific Institution, Research Centre for Medical Genetics, Moscow, Russia
| | | | | | | | | | | | - Roman Vladimirovich Veiko
- Federal State Budgetary Scientific Institution, Research Centre for Medical Genetics, Moscow, Russia
| | | | - Pavel Umriukhin
- Federal State Budgetary Scientific Institution, Research Centre for Medical Genetics, Moscow, Russia
- I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation, Moscow, Russia
- P.K. Anokhin Institute of Normal Physiology, Moscow, Russia
| | | | | | - Sergey Ivanovich Kutsev
- Federal State Budgetary Scientific Institution, Research Centre for Medical Genetics, Moscow, Russia
| | - Natalia Nikolaevna Veiko
- Federal State Budgetary Scientific Institution, Research Centre for Medical Genetics, Moscow, Russia
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Metformin: Sentinel of the Epigenetic Landscapes That Underlie Cell Fate and Identity. Biomolecules 2020; 10:biom10050780. [PMID: 32443566 PMCID: PMC7277648 DOI: 10.3390/biom10050780] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/08/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022] Open
Abstract
The biguanide metformin is the first drug to be tested as a gerotherapeutic in the clinical trial TAME (Targeting Aging with Metformin). The current consensus is that metformin exerts indirect pleiotropy on core metabolic hallmarks of aging, such as the insulin/insulin-like growth factor 1 and AMP-activated protein kinase/mammalian Target Of Rapamycin signaling pathways, downstream of its primary inhibitory effect on mitochondrial respiratory complex I. Alternatively, but not mutually exclusive, metformin can exert regulatory effects on components of the biologic machinery of aging itself such as chromatin-modifying enzymes. An integrative metabolo-epigenetic outlook supports a new model whereby metformin operates as a guardian of cell identity, capable of retarding cellular aging by preventing the loss of the information-theoretic nature of the epigenome. The ultimate anti-aging mechanism of metformin might involve the global preservation of the epigenome architecture, thereby ensuring cell fate commitment and phenotypic outcomes despite the challenging effects of aging noise. Metformin might therefore inspire the development of new gerotherapeutics capable of preserving the epigenome architecture for cell identity. Such gerotherapeutics should replicate the ability of metformin to halt the erosion of the epigenetic landscape, mitigate the loss of cell fate commitment, delay stochastic/environmental DNA methylation drifts, and alleviate cellular senescence. Yet, it remains a challenge to confirm if regulatory changes in higher-order genomic organizers can connect the capacity of metformin to dynamically regulate the three-dimensional nature of epigenetic landscapes with the 4th dimension, the aging time.
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