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Bhattacharya M, Lyda SF, Lei EP. Chromatin insulator mechanisms ensure accurate gene expression by controlling overall 3D genome organization. Curr Opin Genet Dev 2024; 87:102208. [PMID: 38810546 DOI: 10.1016/j.gde.2024.102208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/24/2024] [Accepted: 05/13/2024] [Indexed: 05/31/2024]
Abstract
Chromatin insulators are DNA-protein complexes that promote specificity of enhancer-promoter interactions and maintain distinct transcriptional states through control of 3D genome organization. In this review, we highlight recent work visualizing how mammalian CCCTC-binding factor acts as a boundary to dynamic DNA loop extrusion mediated by cohesin. We also discuss new studies in both mammals and Drosophila that elucidate biological redundancy of chromatin insulator function and interplay with transcription with respect to topologically associating domain formation. Finally, we present novel concepts in spatiotemporal regulation of chromatin insulator function during differentiation and development and possible consequences of disrupted insulator activity on cellular proliferation.
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Affiliation(s)
- Mallika Bhattacharya
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Savanna F Lyda
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, USA; Biological Sciences Graduate Program, University of Maryland, College Park, USA
| | - Elissa P Lei
- Nuclear Organization and Gene Expression Section, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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Sokolov V, Kyrchanova O, Klimenko N, Fedotova A, Ibragimov A, Maksimenko O, Georgiev P. New Drosophila promoter-associated architectural protein Mzfp1 interacts with CP190 and is required for housekeeping gene expression and insulator activity. Nucleic Acids Res 2024; 52:6886-6905. [PMID: 38769058 PMCID: PMC11229372 DOI: 10.1093/nar/gkae393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 04/20/2024] [Accepted: 05/10/2024] [Indexed: 05/22/2024] Open
Abstract
In Drosophila, a group of zinc finger architectural proteins recruits the CP190 protein to the chromatin, an interaction that is essential for the functional activity of promoters and insulators. In this study, we describe a new architectural C2H2 protein called Madf and Zinc-Finger Protein 1 (Mzfp1) that interacts with CP190. Mzfp1 has an unusual structure that includes six C2H2 domains organized in a C-terminal cluster and two tandem MADF domains. Mzfp1 predominantly binds to housekeeping gene promoters located in both euchromatin and heterochromatin genome regions. In vivo mutagenesis studies showed that Mzfp1 is an essential protein, and both MADF domains and the CP190 interaction region are required for its functional activity. The C2H2 cluster is sufficient for the specific binding of Mzfp1 to regulatory elements, while the second MADF domain is required for Mzfp1 recruitment to heterochromatin. Mzfp1 binds to the proximal part of the Fub boundary that separates regulatory domains of the Ubx and abd-A genes in the Bithorax complex. Mzfp1 participates in Fub functions in cooperation with the architectural proteins Pita and Su(Hw). Thus, Mzfp1 is a new architectural C2H2 protein involved in the organization of active promoters and insulators in Drosophila.
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Affiliation(s)
- Vladimir Sokolov
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Natalia Klimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Anna Fedotova
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Airat Ibragimov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Oksana Maksimenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
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Gelléri M, Chen SY, Hübner B, Neumann J, Kröger O, Sadlo F, Imhoff J, Hendzel MJ, Cremer M, Cremer T, Strickfaden H, Cremer C. True-to-scale DNA-density maps correlate with major accessibility differences between active and inactive chromatin. Cell Rep 2023; 42:112567. [PMID: 37243597 DOI: 10.1016/j.celrep.2023.112567] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 03/02/2023] [Accepted: 05/10/2023] [Indexed: 05/29/2023] Open
Abstract
Chromatin compaction differences may have a strong impact on accessibility of individual macromolecules and macromolecular assemblies to their DNA target sites. Estimates based on fluorescence microscopy with conventional resolution, however, suggest only modest compaction differences (∼2-10×) between the active nuclear compartment (ANC) and inactive nuclear compartment (INC). Here, we present maps of nuclear landscapes with true-to-scale DNA densities, ranging from <5 to >300 Mbp/μm3. Maps are generated from individual human and mouse cell nuclei with single-molecule localization microscopy at ∼20 nm lateral and ∼100 nm axial optical resolution and are supplemented by electron spectroscopic imaging. Microinjection of fluorescent nanobeads with sizes corresponding to macromolecular assemblies for transcription into nuclei of living cells demonstrates their localization and movements within the ANC and exclusion from the INC.
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Affiliation(s)
- Márton Gelléri
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany.
| | - Shih-Ya Chen
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Barbara Hübner
- Biocenter, Department Biology II, Ludwig Maximilian University (LMU), 82152 Martinsried, Germany
| | - Jan Neumann
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany; Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Ole Kröger
- Interdisciplinary Center for Scientific Computing (IWR), University Heidelberg, 69120 Heidelberg, Germany
| | - Filip Sadlo
- Interdisciplinary Center for Scientific Computing (IWR), University Heidelberg, 69120 Heidelberg, Germany
| | - Jorg Imhoff
- Neuroconsult GmbH, 69120 Heidelberg, Germany
| | - Michael J Hendzel
- Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 1Z2, Canada
| | - Marion Cremer
- Biocenter, Department Biology II, Ludwig Maximilian University (LMU), 82152 Martinsried, Germany
| | - Thomas Cremer
- Biocenter, Department Biology II, Ludwig Maximilian University (LMU), 82152 Martinsried, Germany
| | - Hilmar Strickfaden
- Departments of Cell Biology and Oncology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 1Z2, Canada.
| | - Christoph Cremer
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany; Max Planck Institute for Chemistry, 55128 Mainz, Germany; Interdisciplinary Center for Scientific Computing (IWR), University Heidelberg, 69120 Heidelberg, Germany; Kirchhoff Institute for Physics, University Heidelberg, 69120 Heidelberg, Germany.
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A Tremendous Reorganization Journey for the 3D Chromatin Structure from Gametes to Embryos. Genes (Basel) 2022; 13:genes13101864. [PMID: 36292750 PMCID: PMC9602195 DOI: 10.3390/genes13101864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/02/2022] [Accepted: 10/12/2022] [Indexed: 11/04/2022] Open
Abstract
The 3D chromatin structure within the nucleus is important for gene expression regulation and correct developmental programs. Recently, the rapid development of low-input chromatin conformation capture technologies has made it possible to study 3D chromatin structures in gametes, zygotes and early embryos in a variety of species, including flies, vertebrates and mammals. There are distinct 3D chromatin structures within the male and female gametes. Following the fertilization of male and female gametes, fertilized eggs undergo drastic epigenetic reprogramming at multi levels, including the 3D chromatin structure, to convert the terminally differentiated gamete state into the totipotent state, which can give rise to an individual. However, to what extent the 3D chromatin structure reorganization is evolutionarily conserved and what the underlying mechanisms are for the tremendous reorganization in early embryos remain elusive. Here, we review the latest findings on the 3D chromatin structure reorganization during embryogenesis, and discuss the convergent and divergent reprogramming patterns and key molecular mechanisms for the 3D chromatin structure reorganization from gametes to embryos in different species. These findings shed light on how the 3D chromatin structure reorganization contribute to embryo development in different species. The findings also indicate the role of the 3D chromatin structure on the acquisition of totipotent developmental potential.
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Asymmetric chromatin retention and nuclear envelopes separate chromosomes in fused cells in vivo. Commun Biol 2022; 5:953. [PMID: 36123528 PMCID: PMC9485224 DOI: 10.1038/s42003-022-03874-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 08/23/2022] [Indexed: 11/23/2022] Open
Abstract
Hybrid cells derived through fertilization or somatic cell fusion recognize and separate chromosomes of different origins. The underlying mechanisms are unknown but could prevent aneuploidy and tumor formation. Here, we acutely induce fusion between Drosophila neural stem cells (neuroblasts; NBs) and differentiating ganglion mother cells (GMCs) in vivo to define how epigenetically distinct chromatin is recognized and segregated. We find that NB-GMC hybrid cells align both endogenous (neuroblast-origin) and ectopic (GMC-origin) chromosomes at the metaphase plate through centrosome derived dual-spindles. Physical separation of endogenous and ectopic chromatin is achieved through asymmetric, microtubule-dependent chromatin retention in interphase and physical boundaries imposed by nuclear envelopes. The chromatin separation mechanisms described here could apply to the first zygotic division in insects, arthropods, and vertebrates or potentially inform biased chromatid segregation in stem cells. A hybrid fly cell model to test the separation of chromosomes of different origin. Neural stem cell (NB) - ganglion mother cell (GMC) hybrids align the respective chromosomes independently, supported by NB- or GMC-derived centrosomes and their spindles.
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Emerging mechanisms and dynamics of three-dimensional genome organisation at zygotic genome activation. Curr Opin Cell Biol 2022; 74:37-46. [DOI: 10.1016/j.ceb.2021.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 02/07/2023]
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Kurbidaeva A, Purugganan M. Insulators in Plants: Progress and Open Questions. Genes (Basel) 2021; 12:genes12091422. [PMID: 34573404 PMCID: PMC8470105 DOI: 10.3390/genes12091422] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 11/16/2022] Open
Abstract
The genomes of higher eukaryotes are partitioned into topologically associated domains or TADs, and insulators (also known as boundary elements) are the key elements responsible for their formation and maintenance. Insulators were first identified and extensively studied in Drosophila as well as mammalian genomes, and have also been described in yeast and plants. In addition, many insulator proteins are known in Drosophila, and some have been investigated in mammals. However, much less is known about this important class of non-coding DNA elements in plant genomes. In this review, we take a detailed look at known plant insulators across different species and provide an overview of potential determinants of plant insulator functions, including cis-elements and boundary proteins. We also discuss methods previously used in attempts to identify plant insulators, provide a perspective on their importance for research and biotechnology, and discuss areas of potential future research.
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Independence of chromatin conformation and gene regulation during Drosophila dorsoventral patterning. Nat Genet 2021; 53:487-499. [PMID: 33795866 PMCID: PMC8035076 DOI: 10.1038/s41588-021-00799-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 01/21/2021] [Indexed: 02/01/2023]
Abstract
The relationship between chromatin organization and gene regulation remains unclear. While disruption of chromatin domains and domain boundaries can lead to misexpression of developmental genes, acute depletion of regulators of genome organization has a relatively small effect on gene expression. It is therefore uncertain whether gene expression and chromatin state drive chromatin organization or whether changes in chromatin organization facilitate cell-type-specific activation of gene expression. Here, using the dorsoventral patterning of the Drosophila melanogaster embryo as a model system, we provide evidence for the independence of chromatin organization and dorsoventral gene expression. We define tissue-specific enhancers and link them to expression patterns using single-cell RNA-seq. Surprisingly, despite tissue-specific chromatin states and gene expression, chromatin organization is largely maintained across tissues. Our results indicate that tissue-specific chromatin conformation is not necessary for tissue-specific gene expression but rather acts as a scaffold facilitating gene expression when enhancers become active.
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Lezcano ÓM, Sánchez-Polo M, Ruiz JL, Gómez-Díaz E. Chromatin Structure and Function in Mosquitoes. Front Genet 2020; 11:602949. [PMID: 33365050 PMCID: PMC7750206 DOI: 10.3389/fgene.2020.602949] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/29/2020] [Indexed: 12/27/2022] Open
Abstract
The principles and function of chromatin and nuclear architecture have been extensively studied in model organisms, such as Drosophila melanogaster. However, little is known about the role of these epigenetic processes in transcriptional regulation in other insects including mosquitoes, which are major disease vectors and a worldwide threat for human health. Some of these life-threatening diseases are malaria, which is caused by protozoan parasites of the genus Plasmodium and transmitted by Anopheles mosquitoes; dengue fever, which is caused by an arbovirus mainly transmitted by Aedes aegypti; and West Nile fever, which is caused by an arbovirus transmitted by Culex spp. In this contribution, we review what is known about chromatin-associated mechanisms and the 3D genome structure in various mosquito vectors, including Anopheles, Aedes, and Culex spp. We also discuss the similarities between epigenetic mechanisms in mosquitoes and the model organism Drosophila melanogaster, and advocate that the field could benefit from the cross-application of state-of-the-art functional genomic technologies that are well-developed in the fruit fly. Uncovering the mosquito regulatory genome can lead to the discovery of unique regulatory networks associated with the parasitic life-style of these insects. It is also critical to understand the molecular interactions between the vectors and the pathogens that they transmit, which could hold the key to major breakthroughs on the fight against mosquito-borne diseases. Finally, it is clear that epigenetic mechanisms controlling mosquito environmental plasticity and evolvability are also of utmost importance, particularly in the current context of globalization and climate change.
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Affiliation(s)
| | | | - José L. Ruiz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN), Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Elena Gómez-Díaz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN), Consejo Superior de Investigaciones Científicas, Granada, Spain
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Noordermeer D. 3D genome organization: setting the stage and introducing its players. Brief Funct Genomics 2020; 19:69-70. [PMID: 32239212 DOI: 10.1093/bfgp/elaa006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daan Noordermeer
- Chromatin Dynamics Group, Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
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