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Naor T, Nogin Y, Nehme E, Ferdman B, Weiss LE, Alalouf O, Shechtman Y. Quantifying cell-cycle-dependent chromatin dynamics during interphase by live 3D tracking. iScience 2022; 25:104197. [PMID: 35494233 PMCID: PMC9051635 DOI: 10.1016/j.isci.2022.104197] [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: 10/10/2021] [Revised: 02/02/2022] [Accepted: 03/31/2022] [Indexed: 11/30/2022] Open
Abstract
The study of cell cycle progression and regulation is important to our understanding of fundamental biophysics, aging, and disease mechanisms. Local chromatin movements are generally considered to be constrained and relatively consistent during all interphase stages, although recent advances in our understanding of genome organization challenge this claim. Here, we use high spatiotemporal resolution, 4D (x, y, z and time) localization microscopy by point-spread-function (PSF) engineering and deep learning-based image analysis, for live imaging of mouse embryonic fibroblast (MEF 3T3) and MEF 3T3 double Lamin A Knockout (LmnaKO) cell lines, to characterize telomere diffusion during the interphase. We detected varying constraint levels imposed on chromatin, which are prominently decreased during G0/G1. Our 4D measurements of telomere diffusion offer an effective method to investigate chromatin dynamics and reveal cell-cycle-dependent motion constraints, which may be caused by various cellular processes. PSF engineering allows scan-free, high spatiotemporal live 3D telomere tracking During the G0/G1 phase, telomere motion is less constrained than in other phases There is observable difference between lateral (xy) and axial (z) chromatin motion In Lamin A-depleted cells, motion constraint was reduced
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2
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Delker RK, Munce RH, Hu M, Mann RS. Fluorescent labeling of genomic loci in Drosophila imaginal discs with heterologous DNA-binding proteins. CELL REPORTS METHODS 2022; 2:100175. [PMID: 35475221 PMCID: PMC9017127 DOI: 10.1016/j.crmeth.2022.100175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/02/2021] [Accepted: 02/11/2022] [Indexed: 11/25/2022]
Abstract
Using the Drosophila melanogaster Hox gene Ultrabithorax (Ubx) as an example, we demonstrate the use of three heterologous DNA-binding protein systems-LacI/LacO, ParB1/ParS1, and ParB2/ParS2-to label genomic loci in imaginal discs with the insertion of a small DNA tag. We compare each system, considering the impact of labeling in genomic regions (1) inside versus outside of a transcribed gene body and (2) with varying chromatin accessibility. We demonstrate the value of this system by interrogating the relationship between gene expression level and enhancer-promoter distance, as well as inter-allelic distance at the Ubx locus. We find that the distance between an essential intronic cis-regulatory element, anterobithorax (abx), and the promoter does not vary with expression level. In contrast, inter-allelic distance correlates with Ubx expression level.
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Affiliation(s)
- Rebecca K. Delker
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Ross H. Munce
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Michelle Hu
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
| | - Richard S. Mann
- Department of Biochemistry and Molecular Biophysics, Columbia University Irving Medical Center, New York, NY, USA
- Department of Neuroscience, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
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3
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Lorber D, Volk T. Evaluation of chromatin mesoscale organization. APL Bioeng 2022; 6:010902. [PMID: 35071965 PMCID: PMC8758204 DOI: 10.1063/5.0069286] [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: 08/30/2021] [Accepted: 11/29/2021] [Indexed: 11/21/2022] Open
Abstract
Chromatin organization in the nucleus represents an important aspect of transcription regulation. Most of the studies so far focused on the chromatin structure in cultured cells or in fixed tissue preparations. Here, we discuss the various approaches for deciphering chromatin 3D organization with an emphasis on the advantages of live imaging approaches.
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Affiliation(s)
- Dana Lorber
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Talila Volk
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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4
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Johanson TM, Keenan CR, Allan RS. Shedding Structured Light on Molecular Immunity: The Past, Present and Future of Immune Cell Super Resolution Microscopy. Front Immunol 2021; 12:754200. [PMID: 34975842 PMCID: PMC8715013 DOI: 10.3389/fimmu.2021.754200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022] Open
Abstract
In the two decades since the invention of laser-based super resolution microscopy this family of technologies has revolutionised the way life is viewed and understood. Its unparalleled resolution, speed, and accessibility makes super resolution imaging particularly useful in examining the highly complex and dynamic immune system. Here we introduce the super resolution technologies and studies that have already fundamentally changed our understanding of a number of central immunological processes and highlight other immunological puzzles only addressable in super resolution.
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Affiliation(s)
- Timothy M. Johanson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Christine R. Keenan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Rhys S. Allan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
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5
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Nehme E, Ferdman B, Weiss LE, Naor T, Freedman D, Michaeli T, Shechtman Y. Learning Optimal Wavefront Shaping for Multi-Channel Imaging. IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 2021; 43:2179-2192. [PMID: 34029185 DOI: 10.1109/tpami.2021.3076873] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fast acquisition of depth information is crucial for accurate 3D tracking of moving objects. Snapshot depth sensing can be achieved by wavefront coding, in which the point-spread function (PSF) is engineered to vary distinctively with scene depth by altering the detection optics. In low-light applications, such as 3D localization microscopy, the prevailing approach is to condense signal photons into a single imaging channel with phase-only wavefront modulation to achieve a high pixel-wise signal to noise ratio. Here we show that this paradigm is generally suboptimal and can be significantly improved upon by employing multi-channel wavefront coding, even in low-light applications. We demonstrate our multi-channel optimization scheme on 3D localization microscopy in densely labelled live cells where detectability is limited by overlap of modulated PSFs. At extreme densities, we show that a split-signal system, with end-to-end learned phase masks, doubles the detection rate and reaches improved precision compared to the current state-of-the-art, single-channel design. We implement our method using a bifurcated optical system, experimentally validating our approach by snapshot volumetric imaging and 3D tracking of fluorescently labelled subcellular elements in dense environments.
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6
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Chin MY, Espinosa JA, Pohan G, Markossian S, Arkin MR. Reimagining dots and dashes: Visualizing structure and function of organelles for high-content imaging analysis. Cell Chem Biol 2021; 28:320-337. [PMID: 33600764 PMCID: PMC7995685 DOI: 10.1016/j.chembiol.2021.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/18/2020] [Accepted: 01/20/2021] [Indexed: 12/16/2022]
Abstract
Organelles are responsible for biochemical and cellular processes that sustain life and their dysfunction causes diseases from cancer to neurodegeneration. While researchers are continuing to appreciate new roles of organelles in disease, the rapid development of specifically targeted fluorescent probes that report on the structure and function of organelles will be critical to accelerate drug discovery. Here, we highlight four organelles that collectively exemplify the progression of phenotypic discovery, starting with mitochondria, where many functional probes have been described, then continuing with lysosomes and Golgi and concluding with nascently described membraneless organelles. We introduce emerging probe designs to explore organelle-specific morphology and dynamics and highlight recent case studies using high-content analysis to stimulate further development of probes and approaches for organellar high-throughput screening.
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Affiliation(s)
- Marcus Y Chin
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Jether Amos Espinosa
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Grace Pohan
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Sarine Markossian
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Michelle R Arkin
- Small Molecule Discovery Center and Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA.
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7
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Schreier VN, Loehr MO, Deng T, Lattmann E, Hajnal A, Neuhauss SC, Luedtke NW. Fluorescent dATP for DNA Synthesis In Vivo. ACS Chem Biol 2020; 15:2996-3003. [PMID: 33108866 DOI: 10.1021/acschembio.0c00654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Fluorescent nucleoside triphosphates are powerful probes of DNA synthesis, but their potential use in living animals has been previously underexplored. Here, we report the synthesis and characterization of 7-deaza-(1,2,3-triazole)-2'-deoxyadenosine-5'-triphosphate (dATP) derivatives of tetramethyl rhodamine ("TAMRA-dATP"), cyanine ("Cy3-dATP"), and boron-dipyrromethene ("BODIPY-dATP"). Upon microinjection into live zebrafish embryos, all three compounds were incorporated into the DNA of dividing cells; however, their impact on embryonic toxicity was highly variable, depending on the exact structure of the dye. TAMRA-EdATP exhibited superior characteristics in terms of its high brightness, low toxicity, and rapid incorporation and depletion kinetics in both a vertebrate (zebrafish) and a nematode (Caenorhabditis elegans). TAMRA-EdATP allows for unprecedented, real-time visualization of DNA replication and chromosome segregation in vivo.
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Affiliation(s)
- Verena N. Schreier
- Department of Chemistry, University of Zurich, Zurich CH-8006, Switzerland
| | - Morten O. Loehr
- Department of Chemistry, University of Zurich, Zurich CH-8006, Switzerland
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0G4, Canada
| | - Ting Deng
- Department of Molecular Life Sciences, University of Zurich, Zurich CH-8006, Switzerland
| | - Evelyn Lattmann
- Department of Molecular Life Sciences, University of Zurich, Zurich CH-8006, Switzerland
| | - Alex Hajnal
- Department of Molecular Life Sciences, University of Zurich, Zurich CH-8006, Switzerland
| | - Stephan C.F. Neuhauss
- Department of Molecular Life Sciences, University of Zurich, Zurich CH-8006, Switzerland
| | - Nathan W. Luedtke
- Department of Chemistry, University of Zurich, Zurich CH-8006, Switzerland
- Department of Chemistry, McGill University, Montreal, Quebec H3A 0G4, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec H3A 0G4, Canada
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Lämmle CA, Varady A, Müller TG, Sturtzel C, Riepl M, Mathes B, Eichhorst J, Sporbert A, Lehmann M, Kräusslich HG, Distel M, Broichhagen J. Photocaged Hoechst Enables Subnuclear Visualization and Cell Selective Staining of DNA in vivo. Chembiochem 2020; 22:548-556. [PMID: 32974998 PMCID: PMC7894298 DOI: 10.1002/cbic.202000465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/17/2020] [Indexed: 12/19/2022]
Abstract
Selective targeting of DNA by means of fluorescent labeling has become a mainstay in the life sciences. While genetic engineering serves as a powerful technique and allows the visualization of nucleic acid by using DNA‐targeting fluorescent fusion proteins in a cell‐type‐ and subcellular‐specific manner, it relies on the introduction of foreign genes. On the other hand, DNA‐binding small fluorescent molecules can be used without genetic engineering, but they are not spatially restricted. Herein, we report a photocaged version of the DNA dye Hoechst33342 (pcHoechst), which can be uncaged by using UV to blue light for the selective staining of chromosomal DNA in subnuclear regions of live cells. Expanding its application to a vertebrate model organism, we demonstrate uncaging in epithelial cells and short‐term cell tracking in vivo in zebrafish. We envision pcHoechst as a valuable tool for targeting and interrogating DNA with precise spatiotemporal resolution in living cells and wild‐type organisms.
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Affiliation(s)
- Carina A Lämmle
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - Adam Varady
- St. Anna Children's Cancer Research Institute, Innovative Cancer Models, Zimmermannplatz 10, 1090, Vienna, Austria
| | - Thorsten G Müller
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany
| | - Caterina Sturtzel
- St. Anna Children's Cancer Research Institute, Innovative Cancer Models, Zimmermannplatz 10, 1090, Vienna, Austria.,Zebrafish Platform Austria for preclinical drug screening (ZANDR), Zimmermannplatz 10, 1090, Vienna, Austria
| | - Michael Riepl
- St. Anna Children's Cancer Research Institute, Innovative Cancer Models, Zimmermannplatz 10, 1090, Vienna, Austria
| | - Bettina Mathes
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - Jenny Eichhorst
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Anje Sporbert
- Advanced Light Microscopy, Max Delbrück Centrum for Molecular Medicine Berlin in the Helmholtz Association, Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Martin Lehmann
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125, Berlin, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 344, 69120, Heidelberg, Germany
| | - Martin Distel
- St. Anna Children's Cancer Research Institute, Innovative Cancer Models, Zimmermannplatz 10, 1090, Vienna, Austria.,Zebrafish Platform Austria for preclinical drug screening (ZANDR), Zimmermannplatz 10, 1090, Vienna, Austria
| | - Johannes Broichhagen
- Department of Chemical Biology, Max Planck Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany.,Department of Chemical Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Straße 10, 13125, Berlin, Germany
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9
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Chromatin Architectural Factors as Safeguards against Excessive Supercoiling during DNA Replication. Int J Mol Sci 2020; 21:ijms21124504. [PMID: 32599919 PMCID: PMC7349988 DOI: 10.3390/ijms21124504] [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: 06/06/2020] [Revised: 06/17/2020] [Accepted: 06/23/2020] [Indexed: 12/21/2022] Open
Abstract
Key DNA transactions, such as genome replication and transcription, rely on the speedy translocation of specialized protein complexes along a double-stranded, right-handed helical template. Physical tethering of these molecular machines during translocation, in conjunction with their internal architectural features, generates DNA topological strain in the form of template supercoiling. It is known that the build-up of transient excessive supercoiling poses severe threats to genome function and stability and that highly specialized enzymes—the topoisomerases (TOP)—have evolved to mitigate these threats. Furthermore, due to their intracellular abundance and fast supercoil relaxation rates, it is generally assumed that these enzymes are sufficient in coping with genome-wide bursts of excessive supercoiling. However, the recent discoveries of chromatin architectural factors that play important accessory functions have cast reasonable doubts on this concept. Here, we reviewed the background of these new findings and described emerging models of how these accessory factors contribute to supercoil homeostasis. We focused on DNA replication and the generation of positive (+) supercoiling in front of replisomes, where two accessory factors—GapR and HMGA2—from pro- and eukaryotic cells, respectively, appear to play important roles as sinks for excessive (+) supercoiling by employing a combination of supercoil constrainment and activation of topoisomerases. Looking forward, we expect that additional factors will be identified in the future as part of an expanding cellular repertoire to cope with bursts of topological strain. Furthermore, identifying antagonists that target these accessory factors and work synergistically with clinically relevant topoisomerase inhibitors could become an interesting novel strategy, leading to improved treatment outcomes.
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10
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Birk UJ. Super-Resolution Microscopy of Chromatin. Genes (Basel) 2019; 10:E493. [PMID: 31261775 PMCID: PMC6678334 DOI: 10.3390/genes10070493] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 06/17/2019] [Accepted: 06/26/2019] [Indexed: 01/05/2023] Open
Abstract
Since the advent of super-resolution microscopy, countless approaches and studies have been published contributing significantly to our understanding of cellular processes. With the aid of chromatin-specific fluorescence labeling techniques, we are gaining increasing insight into gene regulation and chromatin organization. Combined with super-resolution imaging and data analysis, these labeling techniques enable direct assessment not only of chromatin interactions but also of the function of specific chromatin conformational states.
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Affiliation(s)
- Udo J Birk
- University of Applied Sciences HTW Chur, Pulvermühlestrasse 57, 7004 Chur, Switzerland.
- Institut für Physik, Universität Mainz, 55122 Mainz, Germany.
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11
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Matzke AJ, Lin WD, Matzke M. Evidence That Ion-Based Signaling Initiating at the Cell Surface Can Potentially Influence Chromatin Dynamics and Chromatin-Bound Proteins in the Nucleus. FRONTIERS IN PLANT SCIENCE 2019; 10:1267. [PMID: 31681370 PMCID: PMC6811650 DOI: 10.3389/fpls.2019.01267] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/11/2019] [Indexed: 05/18/2023]
Abstract
We have developed tools and performed pilot experiments to test the hypothesis that an intracellular ion-based signaling pathway, provoked by an extracellular stimulus acting at the cell surface, can influence interphase chromosome dynamics and chromatin-bound proteins in the nucleus. The experimental system employs chromosome-specific fluorescent tags and the genome-encoded fluorescent pH sensor SEpHluorinA227D, which has been targeted to various intracellular membranes and soluble compartments in root cells of Arabidopsis thaliana. We are using this system and three-dimensional live cell imaging to visualize whether fluorescent-tagged interphase chromosome sites undergo changes in constrained motion concurrently with reductions in membrane-associated pH elicited by extracellular ATP, which is known to trigger a cascade of events in plant cells including changes in calcium ion concentrations, pH, and membrane potential. To examine possible effects of the proposed ion-based signaling pathway directly at the chromatin level, we generated a pH-sensitive fluorescent DNA-binding protein that allows pH changes to be monitored at specific genomic sites. Results obtained using these tools support the existence of a rapid, ion-based signaling pathway that initiates at the cell surface and reaches the nucleus to induce alterations in interphase chromatin mobility and the surrounding pH of chromatin-bound proteins. Such a pathway could conceivably act under natural circumstances to allow external stimuli to swiftly influence gene expression by affecting interphase chromosome movement and the structures and/or activities of chromatin-associated proteins.
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Affiliation(s)
| | | | - Marjori Matzke
- *Correspondence: Antonius J.M. Matzke, ; Marjori Matzke,
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12
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Szydlowski NA, Go JS, Hu YS. Chromatin imaging and new technologies for imaging the nucleome. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2018; 11:e1442. [PMID: 30456928 DOI: 10.1002/wsbm.1442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 10/03/2018] [Accepted: 10/16/2018] [Indexed: 12/15/2022]
Abstract
Synergistic developments in advanced fluorescent imaging and labeling techniques enable direct visualization of the chromatin structure and dynamics at the nanoscale level and in live cells. Super-resolution imaging encompasses a class of constantly evolving techniques that break the diffraction limit of fluorescence microscopy. Structured illumination microscopy provides a twofold resolution improvement and can readily achieve live multicolor imaging using conventional fluorophores. Single-molecule localization microscopy increases the spatial resolution by approximately 10-fold at the expense of slower acquisition speed. Stimulated emission-depletion microscopy generates a roughly fivefold resolution improvement with an imaging speed proportional to the scanning area. In parallel, advanced labeling strategies have been developed to "light up" global and sequence-specific DNA regions. DNA binding dyes have been exploited to achieve high labeling densities in single-molecule localization microscopy and enhance contrast in correlated light and electron microscopy. New-generation Oligopaint utilizes bioinformatics analyses to optimize the design of fluorescence in situ hybridization probes. Through sequential and combinatorial labeling, direct characterization of the DNA domain volume and length as well as the spatial organization of distinct topologically associated domains has been reported. In live cells, locus-specific labeling has been achieved by either inserting artificial loci next to the gene of interest, such as the repressor-operator array systems, or utilizing genome editing tools, including zinc finer proteins, transcription activator-like effectors, and the clustered regularly interspaced short palindromic repeats systems. Combined with single-molecule tracking, these labeling techniques enable direct visualization of intra- and inter-chromatin interactions. This article is categorized under: Laboratory Methods and Technologies > Imaging.
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Affiliation(s)
- Nicole A Szydlowski
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois
| | - Jane S Go
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois
| | - Ying S Hu
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois
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