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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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2
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Abstract
Multichannel imaging is used as a readout of relative localization of two or more components and is often the first step in investigating functional ensembles in cells. However, the localization volume of diffraction-limited light microscopy (approx. 200 nm by 500 nm) can accommodate hundred of proteins, calling for increased resolution for these types of analyses. Here, we present a protocol for 4-channel imaging using structured illumination microscopy (SIM), which increases resolution by a factor of two. We use adherent, fixed cells to identify the localization of adhesion proteins using immunofluorescence and fluorescent proteins. We discuss how labeling with the necessary brightness is achieved and how data has to be processed for colocalization analysis.
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Initial high-resolution microscopic mapping of active and inactive regulatory sequences proves non-random 3D arrangements in chromatin domain clusters. Epigenetics Chromatin 2017; 10:39. [PMID: 28784182 PMCID: PMC5547466 DOI: 10.1186/s13072-017-0146-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/31/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The association of active transcription regulatory elements (TREs) with DNAse I hypersensitivity (DHS[+]) and an 'open' local chromatin configuration has long been known. However, the 3D topography of TREs within the nuclear landscape of individual cells in relation to their active or inactive status has remained elusive. Here, we explored the 3D nuclear topography of active and inactive TREs in the context of a recently proposed model for a functionally defined nuclear architecture, where an active and an inactive nuclear compartment (ANC-INC) form two spatially co-aligned and functionally interacting networks. RESULTS Using 3D structured illumination microscopy, we performed 3D FISH with differently labeled DNA probe sets targeting either sites with DHS[+], apparently active TREs, or DHS[-] sites harboring inactive TREs. Using an in-house image analysis tool, DNA targets were quantitatively mapped on chromatin compaction shaped 3D nuclear landscapes. Our analyses present evidence for a radial 3D organization of chromatin domain clusters (CDCs) with layers of increasing chromatin compaction from the periphery to the CDC core. Segments harboring active TREs are significantly enriched at the decondensed periphery of CDCs with loops penetrating into interchromatin compartment channels, constituting the ANC. In contrast, segments lacking active TREs (DHS[-]) are enriched toward the compacted interior of CDCs (INC). CONCLUSIONS Our results add further evidence in support of the ANC-INC network model. The different 3D topographies of DHS[+] and DHS[-] sites suggest positional changes of TREs between the ANC and INC depending on their functional state, which might provide additional protection against an inappropriate activation. Our finding of a structural organization of CDCs based on radially arranged layers of different chromatin compaction levels indicates a complex higher-order chromatin organization beyond a dichotomic classification of chromatin into an 'open,' active and 'closed,' inactive state.
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Janel S, Werkmeister E, Bongiovanni A, Lafont F, Barois N. CLAFEM: Correlative light atomic force electron microscopy. Methods Cell Biol 2017; 140:165-185. [PMID: 28528632 DOI: 10.1016/bs.mcb.2017.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Atomic force microscopy (AFM) is becoming increasingly used in the biology field. It can give highly accurate topography and biomechanical quantitative data, such as adhesion, elasticity, and viscosity, on living samples. Nowadays, correlative light electron microscopy is a must-have tool in the biology field that combines different microscopy techniques to spatially and temporally analyze the structure and function of a single sample. Here, we describe the combination of AFM with superresolution light microscopy and electron microscopy. We named this technique correlative light atomic force electron microscopy (CLAFEM) in which AFM can be used on fixed and living cells in association with superresolution light microscopy and further processed for transmission or scanning electron microscopy. We herein illustrate this approach to observe cellular bacterial infection and cytoskeleton. We show that CLAFEM brings complementary information at the cellular level, from on the one hand protein distribution and topography at the nanometer scale and on the other hand elasticity at the piconewton scales to fine ultrastructural details.
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Affiliation(s)
- Sébastien Janel
- Univ. Lille, CNRS UMR 8204, Inserm U1019, CHU Lille, Institut Pasteur de Lille - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Elisabeth Werkmeister
- Univ. Lille, CNRS UMR 8204, Inserm U1019, CHU Lille, Institut Pasteur de Lille - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Antonino Bongiovanni
- Univ. Lille, CNRS UMR 8204, Inserm U1019, CHU Lille, Institut Pasteur de Lille - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Frank Lafont
- Univ. Lille, CNRS UMR 8204, Inserm U1019, CHU Lille, Institut Pasteur de Lille - CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Nicolas Barois
- Univ. Lille, CNRS UMR 8204, Inserm U1019, CHU Lille, Institut Pasteur de Lille - CIIL - Center for Infection and Immunity of Lille, Lille, France
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Gunkel M, Erfle H, Starkuviene V. High-Content Analysis of the Golgi Complex by Correlative Screening Microscopy. Methods Mol Biol 2016; 1496:111-21. [PMID: 27632005 DOI: 10.1007/978-1-4939-6463-5_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Golgi complex plays a central role in a number of diverse cellular processes, and numerous regulators that control these functions and/or morphology of the Golgi complex are known by now. Many of them were identified by large-scale experiments, such as RNAi-based screening. However, high-throughput experiments frequently provide only initial information that a particular protein might play a role in regulating structure and function of the Golgi complex. Multiple follow-up experiments are necessary to functionally characterize the selected hits. In order to speed up the discovery, we have established a system for correlative screening microscopy that combines rapid data collection and high-resolution imaging in one experiment. We describe here a combination of wide-field microscopy and dual-color direct stochastical optical reconstruction microscopy (dSTORM). We apply the technique to simultaneously capture and differentiate alterations of the cis- and trans-Golgi network when depleting several proteins in a singular and combinatorial manner.
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Affiliation(s)
- Manuel Gunkel
- BioQuant, University of Heidelberg, 69120, Heidelberg, Germany
| | - Holger Erfle
- BioQuant, University of Heidelberg, 69120, Heidelberg, Germany.
| | - Vytaute Starkuviene
- BioQuant, University of Heidelberg, 69120, Heidelberg, Germany
- Department of Biochemistry and Molecular Biology, Faculty of Natural Sciences, Joint Life Sciences Center, University of Vilnius, Vilnius, Lithuania
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Politz JCR, Scalzo D, Groudine M. The redundancy of the mammalian heterochromatic compartment. Curr Opin Genet Dev 2015; 37:1-8. [PMID: 26706451 DOI: 10.1016/j.gde.2015.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/26/2015] [Accepted: 10/28/2015] [Indexed: 01/05/2023]
Abstract
Two chromatin compartments are present in most mammalian cells; the first contains primarily euchromatic, early replicating chromatin and the second, primarily late-replicating heterochromatin, which is the subject of this review. Heterochromatin is concentrated in three intranuclear regions: the nuclear periphery, the perinucleolar space and in pericentromeric bodies. We review recent evidence demonstrating that the heterochromatic compartment is critically involved in global nuclear organization and the maintenance of genome stability, and discuss models regarding how this compartment is formed and maintained. We also evaluate our understanding of how heterochromatic sequences (herein named heterochromatic associated regions (HADs)) might be tethered within these regions and review experiments that reveal the stochastic nature of individual HAD positioning within the compartment. These investigations suggest a substantial level of functional redundancy within the heterochromatic compartment.
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Affiliation(s)
| | - David Scalzo
- Fred Hutchinson Cancer Research Center, Seattle, WA, United States
| | - Mark Groudine
- Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
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Popken J, Dahlhoff M, Guengoer T, Wolf E, Zakhartchenko V. 3D structured illumination microscopy of mammalian embryos and spermatozoa. BMC DEVELOPMENTAL BIOLOGY 2015; 15:46. [PMID: 26610350 PMCID: PMC4661982 DOI: 10.1186/s12861-015-0092-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 10/31/2015] [Indexed: 11/10/2022]
Abstract
Background Super-resolution fluorescence microscopy performed via 3D structured illumination microscopy (3D-SIM) is well established on flat, adherent cells. However, blastomeres of mammalian embryos are non-adherent, round and large. Scanning whole mount mammalian embryos with 3D-SIM is prone to failure due to the movement during scanning and the large distance to the cover glass. Results Here we present a highly detailed protocol that allows performing 3D-SIM on blastomeres of mammalian embryos with an image quality comparable to scans in adherent cells. This protocol was successfully tested on mouse, rabbit and cattle embryos and on rabbit spermatozoa. Conclusions Our protocol provides detailed instructions on embryo staining, blastomere isolation, blastomere attachment, embedding, correct oil predictions, scanning conditions, and oil correction choices after the first scan. Finally, the most common problems are documented and solutions are suggested. To our knowledge, this protocol presents for the first time a highly detailed and practical way to perform 3D-SIM on mammalian embryos and spermatozoa.
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Affiliation(s)
- Jens Popken
- Division of Anthropology and Human Genetics, Biocenter, LMU Munich, Grosshaderner Str. 2, D-82152, Planegg-Martinsried, Germany. .,Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377, Munich, Germany.
| | - Maik Dahlhoff
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377, Munich, Germany.
| | - Tuna Guengoer
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377, Munich, Germany.
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377, Munich, Germany.
| | - Valeri Zakhartchenko
- Chair for Molecular Animal Breeding and Biotechnology, and Laboratory for Functional Genome Analysis (LAFUGA), Gene Center, LMU Munich, Feodor-Lynen-Str. 25, D-81377, Munich, Germany. .,Chair for Molecular Animal Breeding and Biotechnology, LMU Munich, Hackerstr. 27, D-85764, Oberschleissheim, Germany.
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Hübner B, Lomiento M, Mammoli F, Illner D, Markaki Y, Ferrari S, Cremer M, Cremer T. Remodeling of nuclear landscapes during human myelopoietic cell differentiation maintains co-aligned active and inactive nuclear compartments. Epigenetics Chromatin 2015; 8:47. [PMID: 26579212 PMCID: PMC4647504 DOI: 10.1186/s13072-015-0038-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 10/26/2015] [Indexed: 01/08/2023] Open
Abstract
Background Previous studies of higher order chromatin organization in nuclei of mammalian species revealed both structural consistency and species-specific differences between cell lines and during early embryonic development. Here, we extended our studies to nuclear landscapes in the human myelopoietic lineage representing a somatic cell differentiation system. Our longterm goal is a search for structural features of nuclei, which are restricted to certain cell types/species, as compared to features, which are evolutionary highly conserved, arguing for their basic functional roles in nuclear organization. Results Common human hematopoietic progenitors, myeloid precursor cells, differentiated monocytes and granulocytes analyzed by super-resolution fluorescence microscopy and electron microscopy revealed profound differences with respect to global chromatin arrangements, the nuclear space occupied by the interchromatin compartment and the distribution of nuclear pores. In contrast, we noted a consistent organization in all cell types with regard to two co-aligned networks, an active (ANC) and an inactive (INC) nuclear compartment delineated by functionally relevant hallmarks. The ANC is enriched in active RNA polymerase II, splicing speckles and histone signatures for transcriptionally competent chromatin (H3K4me3), whereas the INC carries marks for repressed chromatin (H3K9me3). Conclusions Our findings substantiate the conservation of the recently published ANC-INC network model of mammalian nuclear organization during human myelopoiesis irrespective of profound changes of the global nuclear architecture observed during this differentiation process. According to this model, two spatially co-aligned and functionally interacting active and inactive nuclear compartments (ANC and INC) pervade the nuclear space. Electronic supplementary material The online version of this article (doi:10.1186/s13072-015-0038-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Barbara Hübner
- Department Biology II, Biocenter, Ludwig Maximilians University (LMU), Grosshadernerstr. 2, 82152 Martinsried, Germany ; School of Biological Sciences (SBS), Nanyang Technological University (NTU), Singapore, Singapore
| | - Mariana Lomiento
- Department of Life Sciences, University of Modena (Unimore), Modena, Italy
| | - Fabiana Mammoli
- Department of Life Sciences, University of Modena (Unimore), Modena, Italy
| | - Doris Illner
- Department Biology II, Biocenter, Ludwig Maximilians University (LMU), Grosshadernerstr. 2, 82152 Martinsried, Germany ; Bundeswehr Institute of Radiobiology, Munich, Germany
| | - Yolanda Markaki
- Department Biology II, Biocenter, Ludwig Maximilians University (LMU), Grosshadernerstr. 2, 82152 Martinsried, Germany
| | - Sergio Ferrari
- Department of Life Sciences, University of Modena (Unimore), Modena, Italy
| | - Marion Cremer
- Department Biology II, Biocenter, Ludwig Maximilians University (LMU), Grosshadernerstr. 2, 82152 Martinsried, Germany
| | - Thomas Cremer
- Department Biology II, Biocenter, Ludwig Maximilians University (LMU), Grosshadernerstr. 2, 82152 Martinsried, Germany
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9
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Popken J, Brero A, Koehler D, Schmid VJ, Strauss A, Wuensch A, Guengoer T, Graf A, Krebs S, Blum H, Zakhartchenko V, Wolf E, Cremer T. Reprogramming of fibroblast nuclei in cloned bovine embryos involves major structural remodeling with both striking similarities and differences to nuclear phenotypes of in vitro fertilized embryos. Nucleus 2015; 5:555-89. [PMID: 25482066 PMCID: PMC4615760 DOI: 10.4161/19491034.2014.979712] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Nuclear landscapes were studied during preimplantation development of bovine embryos, generated either by in vitro fertilization (IVF), or generated as cloned embryos by somatic cell nuclear transfer (SCNT) of bovine fetal fibroblasts, using 3-dimensional confocal laser scanning microscopy (3D-CLSM) and structured illumination microscopy (3D-SIM). Nuclear landscapes of IVF and SCNT embryonic nuclei were compared with each other and with fibroblast nuclei. We demonstrate that reprogramming of fibroblast nuclei in cloned embryos requires changes of their landscapes similar to nuclei of IVF embryos. On the way toward the 8-cell stage, where major genome activation occurs, a major lacuna, enriched with splicing factors, was formed in the nuclear interior and chromosome territories (CTs) were shifted toward the nuclear periphery. During further development the major lacuna disappeared and CTs were redistributed throughout the nuclear interior forming a contiguous higher order chromatin network. At all stages of development CTs of IVF and SCNT embryonic nuclei were built up from chromatin domain clusters (CDCs) pervaded by interchromatin compartment (IC) channels. Quantitative analyses revealed a highly significant enrichment of RNA polymerase II and H3K4me3, a marker for transcriptionally competent chromatin, at the periphery of CDCs. In contrast, H3K9me3, a marker for silent chromatin, was enriched in the more compacted interior of CDCs. Despite these striking similarities, we also detected major differences between nuclear landscapes of IVF and cloned embryos. Possible implications of these differences for the developmental potential of cloned animals remain to be investigated. We present a model, which integrates generally applicable structural and functional features of the nuclear landscape.
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Key Words
- 3D-CLSM, 3-dimensional confocal laser scanning microscopy
- 3D-SIM, 3-dimensional structured illumination microscopy
- B23, nucleophosmin B23
- BTA, Bos taurus
- CDC, chromatin domain cluster
- CT, chromosome territory
- EM, electron microscopy
- ENC, embryonic nuclei with conventional nuclear architecture
- ENP, embryonic nuclei with peripheral CT distribution
- H3K4me3
- H3K4me3, histone H3 with tri-methylated lysine 4
- H3K9me3
- H3K9me3, histone H3 with tri-methylated lysine 9
- H3S10p, histone H3 with phosphorylated serine 10
- IC, interchromatin compartment
- IVF, in vitro fertilization
- MCB, major chromatin body
- PR, perichromatin region
- RNA polymerase II
- RNA polymerase II-S2p, RNA polymerase II with phosphorylated serine 2 of its CTD domain
- RNA polymerase II-S5p, RNA polymerase II with phosphorylated serine 5 of its CTD domain
- SC-35, splicing factor SC-35
- SCNT, somatic cell nuclear transfer.
- bovine preimplantation development
- chromatin domain
- chromosome territory
- embryonic genome activation
- in vitro fertilization (IVF)
- interchromatin compartment
- major EGA, major embryonic genome activation
- somatic cell nuclear transfer (SCNT)
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Affiliation(s)
- Jens Popken
- a Division of Anthropology and Human Genetics ; Biocenter; LMU Munich ; Munich , Germany
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Sherman S, Nachmias D, Elia N. A simple, straightforward correlative live-cell-imaging-structured-illumination-microscopy approach for studying organelle dynamics. Microsc Res Tech 2015; 78:777-83. [PMID: 26178911 DOI: 10.1002/jemt.22540] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/08/2015] [Accepted: 06/14/2015] [Indexed: 11/08/2022]
Abstract
Most cellular organelles are highly dynamic and continuously undergo membrane fission and fusion to mediate their function. Documenting organelle dynamics under physiological conditions, therefore, requires high temporal resolution of the recording system. Concurrently, these structures are relatively small and determining their substructural organization is often impossible using conventional microscopy. Structured Illumination Microscopy (SIM) is a super resolution technique providing a two-fold increase in resolution. Importantly, SIM is versatile because it allows the use of any fluorescent dye or protein and, hence, is highly applicable for cell biology. However, similar to other SR techniques, the applicability of SIM to high-speed live cell imaging is limited. Here we present an easy, straightforward methodology for coupling of high-speed live cell recordings, using spinning disk (SD) microscopy, with SIM. Using this simple methodology, we are able to track individual mitochondrial membrane fission and fusion events in real time and to determine the network connectivity and substructural organization of the membrane at high resolution. Applying this methodology to other cellular organelles such as, ER, golgi, and cilia will no doubt contribute to our understanding of membrane dynamics in cells.
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Affiliation(s)
- Shachar Sherman
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben Gurion University of the Negev, Beer, Sheva, 84105, Israel
| | - Dikla Nachmias
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben Gurion University of the Negev, Beer, Sheva, 84105, Israel
| | - Natalie Elia
- Department of Life Sciences and the National Institute for Biotechnology in the Negev (NIBN), Ben Gurion University of the Negev, Beer, Sheva, 84105, Israel
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Cremer T, Cremer M, Hübner B, Strickfaden H, Smeets D, Popken J, Sterr M, Markaki Y, Rippe K, Cremer C. The 4D nucleome: Evidence for a dynamic nuclear landscape based on co-aligned active and inactive nuclear compartments. FEBS Lett 2015; 589:2931-43. [PMID: 26028501 DOI: 10.1016/j.febslet.2015.05.037] [Citation(s) in RCA: 152] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 02/04/2023]
Abstract
Recent methodological advancements in microscopy and DNA sequencing-based methods provide unprecedented new insights into the spatio-temporal relationships between chromatin and nuclear machineries. We discuss a model of the underlying functional nuclear organization derived mostly from electron and super-resolved fluorescence microscopy studies. It is based on two spatially co-aligned, active and inactive nuclear compartments (ANC and INC). The INC comprises the compact, transcriptionally inactive core of chromatin domain clusters (CDCs). The ANC is formed by the transcriptionally active periphery of CDCs, called the perichromatin region (PR), and the interchromatin compartment (IC). The IC is connected to nuclear pores and serves nuclear import and export functions. The ANC is the major site of RNA synthesis. It is highly enriched in epigenetic marks for transcriptionally competent chromatin and RNA Polymerase II. Marks for silent chromatin are enriched in the INC. Multi-scale cross-correlation spectroscopy suggests that nuclear architecture resembles a random obstacle network for diffusing proteins. An increased dwell time of proteins and protein complexes within the ANC may help to limit genome scanning by factors or factor complexes to DNA exposed within the ANC.
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Affiliation(s)
- Thomas Cremer
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany.
| | - Marion Cremer
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Barbara Hübner
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Hilmar Strickfaden
- University of Alberta, Cross Cancer Institute Dept. of Oncology, Edmonton, AB, Canada
| | - Daniel Smeets
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Jens Popken
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Michael Sterr
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Yolanda Markaki
- Biocenter, Department Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Karsten Rippe
- German Cancer Research Center (DKFZ) & BioQuant Center, Research Group Genome Organization & Function, Heidelberg, Germany.
| | - Christoph Cremer
- Institute of Molecular Biology (IMB), Mainz and Institute of Pharmacy and Molecular Biotechnology (IPMB), University of Heidelberg, Germany.
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Smeets D, Markaki Y, Schmid VJ, Kraus F, Tattermusch A, Cerase A, Sterr M, Fiedler S, Demmerle J, Popken J, Leonhardt H, Brockdorff N, Cremer T, Schermelleh L, Cremer M. Three-dimensional super-resolution microscopy of the inactive X chromosome territory reveals a collapse of its active nuclear compartment harboring distinct Xist RNA foci. Epigenetics Chromatin 2014; 7:8. [PMID: 25057298 PMCID: PMC4108088 DOI: 10.1186/1756-8935-7-8] [Citation(s) in RCA: 121] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 04/11/2014] [Indexed: 12/31/2022] Open
Abstract
Background A Xist RNA decorated Barr body is the structural hallmark of the compacted inactive X territory in female mammals. Using super-resolution three-dimensional structured illumination microscopy (3D-SIM) and quantitative image analysis, we compared its ultrastructure with active chromosome territories (CTs) in human and mouse somatic cells, and explored the spatio-temporal process of Barr body formation at onset of inactivation in early differentiating mouse embryonic stem cells (ESCs). Results We demonstrate that all CTs are composed of structurally linked chromatin domain clusters (CDCs). In active CTs the periphery of CDCs harbors low-density chromatin enriched with transcriptionally competent markers, called the perichromatin region (PR). The PR borders on a contiguous channel system, the interchromatin compartment (IC), which starts at nuclear pores and pervades CTs. We propose that the PR and macromolecular complexes in IC channels together form the transcriptionally permissive active nuclear compartment (ANC). The Barr body differs from active CTs by a partially collapsed ANC with CDCs coming significantly closer together, although a rudimentary IC channel system connected to nuclear pores is maintained. Distinct Xist RNA foci, closely adjacent to the nuclear matrix scaffold attachment factor-A (SAF-A) localize throughout Xi along the rudimentary ANC. In early differentiating ESCs initial Xist RNA spreading precedes Barr body formation, which occurs concurrent with the subsequent exclusion of RNA polymerase II (RNAP II). Induction of a transgenic autosomal Xist RNA in a male ESC triggers the formation of an ‘autosomal Barr body’ with less compacted chromatin and incomplete RNAP II exclusion. Conclusions 3D-SIM provides experimental evidence for profound differences between the functional architecture of transcriptionally active CTs and the Barr body. Basic structural features of CT organization such as CDCs and IC channels are however still recognized, arguing against a uniform compaction of the Barr body at the nucleosome level. The localization of distinct Xist RNA foci at boundaries of the rudimentary ANC may be considered as snap-shots of a dynamic interaction with silenced genes. Enrichment of SAF-A within Xi territories and its close spatial association with Xist RNA suggests their cooperative function for structural organization of Xi.
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Affiliation(s)
- Daniel Smeets
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany ; Department of Biochemistry, University of Oxford, Oxford, UK
| | - Yolanda Markaki
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Volker J Schmid
- Institute of Statistics, Ludwig Maximilians University (LMU), Munich, Germany
| | - Felix Kraus
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany ; Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Andrea Cerase
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Michael Sterr
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Susanne Fiedler
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Justin Demmerle
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Jens Popken
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Heinrich Leonhardt
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Neil Brockdorff
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Thomas Cremer
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
| | - Lothar Schermelleh
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany ; Department of Biochemistry, University of Oxford, Oxford, UK
| | - Marion Cremer
- Biocenter, Department of Biology II, Ludwig Maximilians University (LMU), Martinsried, Germany
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Cremer T, Cremer C, Lichter P. Recollections of a scientific journey published in human genetics: from chromosome territories to interphase cytogenetics and comparative genome hybridization. Hum Genet 2014; 133:403-16. [PMID: 24504674 DOI: 10.1007/s00439-014-1425-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 01/19/2014] [Indexed: 10/25/2022]
Abstract
In line with the intentions of an issue celebrating the 50th anniversary of Human Genetics, we focus on a series of frequently cited studies published in this journal during the 1980s and 1990s. These studies have contributed to the rise of molecular cytogenetics. They yielded evidence that chromosomes occupy distinct territories in the mammalian cell nucleus, first obtained with laser-UV-microbeam experiments and thereafter with chromosome painting, and contributed to the development of interphase cytogenetics and comparative genome hybridization. We provide a personal account of experimental concepts, which were developed by us and others, and describe some of the unforeseeable turns and obstacles, which we had to overcome on the way towards an experimental realization. We conclude with a perspective on current developments and goals of molecular cytogenetics.
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Affiliation(s)
- Thomas Cremer
- LMU Biozentrum, Grosshadernerstr. 2, Martinsried, Germany,
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Abstract
Structured illumination microscopy (SIM) with a 3-dimensional illumination pattern allows to double image resolution laterally and axially. For cell biologists, SIM may become an attractive tool for refined colocalization studies and to investigate the assembly of components at higher resolution. In this chapter, we focus on the use of a commercial available SIM setup and provide guidance on sample preparation and image acquisition. We present superresolution images of the cytoskeleton in fixed cells and discuss the potential and limitations for SIM in live imaging.
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Affiliation(s)
- Ulrike Engel
- Center for Organismal Studies and Nikon Imaging Center, Bioquant, University of Heidelberg, Heidelberg, Germany
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