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Schirripa Spagnolo C, Moscardini A, Amodeo R, Beltram F, Luin S. Quantitative determination of fluorescence labeling implemented in cell cultures. BMC Biol 2023; 21:190. [PMID: 37697318 PMCID: PMC10496409 DOI: 10.1186/s12915-023-01685-0] [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: 11/29/2022] [Accepted: 08/18/2023] [Indexed: 09/13/2023] Open
Abstract
BACKGROUND Labeling efficiency is a crucial parameter in fluorescence applications, especially when studying biomolecular interactions. Current approaches for estimating the yield of fluorescent labeling have critical drawbacks that usually lead them to be inaccurate or not quantitative. RESULTS We present a method to quantify fluorescent-labeling efficiency that addresses the critical issues marring existing approaches. The method operates in the same conditions of the target experiments by exploiting a ratiometric evaluation with two fluorophores used in sequential reactions. We show the ability of the protocol to extract reliable quantification for different fluorescent probes, reagents concentrations, and reaction timing and to optimize labeling performance. As paradigm, we consider the labeling of the membrane-receptor TrkA through 4'-phosphopantetheinyl transferase Sfp in living cells, visualizing the results by TIRF microscopy. This investigation allows us to find conditions for demanding single and multi-color single-molecule studies requiring high degrees of labeling. CONCLUSIONS The developed method allows the quantitative determination and the optimization of staining efficiency in any labeling strategy based on stable reactions.
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Affiliation(s)
| | - Aldo Moscardini
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Rosy Amodeo
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
- Present address: Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, Pieve Emanuele, 20072, Milan, Italy
| | - Fabio Beltram
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy
- NEST Laboratory, Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127, Pisa, Italy
| | - Stefano Luin
- NEST Laboratory, Scuola Normale Superiore, Piazza San Silvestro 12, 56127, Pisa, Italy.
- NEST Laboratory, Istituto Nanoscienze-CNR, Piazza San Silvestro 12, 56127, Pisa, Italy.
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2
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Ng WS, Sielaff H, Zhao ZW. Phase Separation-Mediated Chromatin Organization and Dynamics: From Imaging-Based Quantitative Characterizations to Functional Implications. Int J Mol Sci 2022; 23:ijms23148039. [PMID: 35887384 PMCID: PMC9316379 DOI: 10.3390/ijms23148039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 12/14/2022] Open
Abstract
As an effective and versatile strategy to compartmentalize cellular components without the need for lipid membranes, phase separation has been found to underpin a wide range of intranuclear processes, particularly those involving chromatin. Many of the unique physico-chemical properties of chromatin-based phase condensates are harnessed by the cell to accomplish complex regulatory functions in a spatially and temporally controlled manner. Here, we survey key recent findings on the mechanistic roles of phase separation in regulating the organization and dynamics of chromatin-based molecular processes across length scales, packing states and intranuclear functions, with a particular emphasis on quantitative characterizations of these condensates enabled by advanced imaging-based approaches. By illuminating the complex interplay between chromatin and various chromatin-interacting molecular species mediated by phase separation, this review sheds light on an emerging multi-scale, multi-modal and multi-faceted landscape that hierarchically regulates the genome within the highly crowded and dynamic nuclear space. Moreover, deficiencies in existing studies also highlight the need for mechanism-specific criteria and multi-parametric approaches for the characterization of chromatin-based phase separation using complementary techniques and call for greater efforts to correlate the quantitative features of these condensates with their functional consequences in close-to-native cellular contexts.
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Affiliation(s)
- Woei Shyuan Ng
- Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119543, Singapore; (W.S.N.); (H.S.)
- Centre for BioImaging Sciences (CBIS), Faculty of Science, National University of Singapore, Singapore 117557, Singapore
| | - Hendrik Sielaff
- Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119543, Singapore; (W.S.N.); (H.S.)
- Centre for BioImaging Sciences (CBIS), Faculty of Science, National University of Singapore, Singapore 117557, Singapore
| | - Ziqing Winston Zhao
- Department of Chemistry, Faculty of Science, National University of Singapore, Singapore 119543, Singapore; (W.S.N.); (H.S.)
- Centre for BioImaging Sciences (CBIS), Faculty of Science, National University of Singapore, Singapore 117557, Singapore
- Mechanobiology Institute (MBI), National University of Singapore, Singapore 117411, Singapore
- Correspondence:
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3
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Machado M, Steinke S, Ganter M. Plasmodium Reproduction, Cell Size, and Transcription: How to Cope With Increasing DNA Content? Front Cell Infect Microbiol 2021; 11:660679. [PMID: 33898332 PMCID: PMC8062723 DOI: 10.3389/fcimb.2021.660679] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/19/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmodium, the unicellular parasite that causes malaria, evolved a highly unusual mode of reproduction. During its complex life cycle, invasive or transmissive stages alternate with proliferating stages, where a single parasite can produce tens of thousands of progeny. In the clinically relevant blood stage of infection, the parasite replicates its genome up to thirty times and forms a multinucleated cell before daughter cells are assembled. Thus, within a single cell cycle, Plasmodium develops from a haploid to a polypoid cell, harboring multiple copies of its genome. Polyploidy creates several biological challenges, such as imbalances in genome output, and cells can respond to this by changing their size and/or alter the production of RNA species and protein to achieve expression homeostasis. However, the effects and possible adaptations of Plasmodium to the massively increasing DNA content are unknown. Here, we revisit and embed current Plasmodium literature in the context of polyploidy and propose potential mechanisms of the parasite to cope with the increasing gene dosage.
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Affiliation(s)
- Marta Machado
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany.,Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Salome Steinke
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Markus Ganter
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, Heidelberg, Germany
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4
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Shaban HA, Barth R, Bystricky K. Navigating the crowd: visualizing coordination between genome dynamics, structure, and transcription. Genome Biol 2020; 21:278. [PMID: 33203432 PMCID: PMC7670612 DOI: 10.1186/s13059-020-02185-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 10/19/2020] [Indexed: 12/12/2022] Open
Abstract
The eukaryotic genome is hierarchically structured yet highly dynamic. Regulating transcription in this environment demands a high level of coordination to permit many proteins to interact with chromatin fiber at appropriate sites in a timely manner. We describe how recent advances in quantitative imaging techniques overcome caveats of sequencing-based methods (Hi-C and related) by enabling direct visualization of transcription factors and chromatin at high resolution, from single genes to the whole nucleus. We discuss the contribution of fluorescence imaging to deciphering the principles underlying this coordination within the crowded nuclear space in living cells and discuss challenges ahead.
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Affiliation(s)
- Haitham A Shaban
- Spectroscopy Department, Physics Division, National Research Centre, Dokki, Cairo, 12622, Egypt.
- Current Address: Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
| | - Roman Barth
- Department of Bionanoscience, Delft University of Technology, 2628 CJ, Delft, The Netherlands
| | - Kerstin Bystricky
- Laboratoire de Biologie Moléculaire Eucaryote (LBME), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, 31062, Toulouse, France.
- Institut Universitaire de France (IUF), Paris, France.
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5
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Li Y, Yi J, Liu W, Liu Y, Liu J. Gaining insight into cellular cardiac physiology using single particle tracking. J Mol Cell Cardiol 2020; 148:63-77. [PMID: 32871158 DOI: 10.1016/j.yjmcc.2020.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 11/29/2022]
Abstract
Single particle tracking (SPT) is a robust technique to monitor single-molecule behaviors in living cells directly. By this approach, we can uncover the potential biological significance of particle dynamics by statistically characterizing individual molecular behaviors. SPT provides valuable information at the single-molecule level, that could be obscured by simple averaging that is inherent to conventional ensemble measurements. Here, we give a brief introduction to SPT including the commonly used optical implementations, fluorescence labeling strategies, and data analysis methods. We then focus on how SPT has been harnessed to decipher myocardial function. In this context, SPT has provided novel insight into the lateral diffusion of signal receptors and ion channels, the dynamic organization of cardiac nanodomains, subunit composition and stoichiometry of cardiac ion channels, myosin movement along actin filaments, the kinetic features of transcription factors involved in cardiac remodeling, and the intercellular communication by nanotubes. Finally, we speculate on the prospects and challenges of applying SPT to future questions regarding cellular cardiac physiology using SPT.
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Affiliation(s)
- Ying Li
- School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen, 518060, China.
| | - Jing Yi
- School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen, 518060, China.
| | - Wenjuan Liu
- School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen, 518060, China.
| | - Yun Liu
- The Seventh Affiliated Hospital, Sun Yat-sen University, Guangdong Province, China.
| | - Jie Liu
- School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen, 518060, China.
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6
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Verneri P, Vazquez Echegaray C, Oses C, Stortz M, Guberman A, Levi V. Dynamical reorganization of the pluripotency transcription factors Oct4 and Sox2 during early differentiation of embryonic stem cells. Sci Rep 2020; 10:5195. [PMID: 32251342 PMCID: PMC7089971 DOI: 10.1038/s41598-020-62235-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 03/11/2020] [Indexed: 01/29/2023] Open
Abstract
Pluripotency maintenance requires transcription factors (TFs) that induce genes necessary to preserve the undifferentiated state and repress others involved in differentiation. Recent observations support that the heterogeneous distribution of TFs in the nucleus impacts on gene expression. Thus, it is essential to explore how TFs dynamically organize to fully understand their role in transcription regulation. Here, we examine the distribution of pluripotency TFs Oct4 and Sox2 in the nucleus of embryonic stem (ES) cells and inquire whether their organization changes during early differentiation stages preceding their downregulation. Using ES cells expressing Oct4-YPet or Sox2-YPet, we show that Oct4 and Sox2 partition between nucleoplasm and a few chromatin-dense foci which restructure after inducing differentiation by 2i/LIF withdrawal. Fluorescence correlation spectroscopy showed distinct changes in Oct4 and Sox2 dynamics after differentiation induction. Specifically, we detected an impairment of Oct4-chromatin interactions whereas Sox2 only showed slight variations in its short-lived, and probably more unspecific, interactions with chromatin. Our results reveal that differentiation cues trigger early changes of Oct4 and Sox2 nuclear distributions that also include modifications in TF-chromatin interactions. This dynamical reorganization precedes Oct4 and Sox2 downregulation and may contribute to modulate their function at early differentiation stages.
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Affiliation(s)
- Paula Verneri
- CONICET - Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina
| | - Camila Vazquez Echegaray
- CONICET - Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina
| | - Camila Oses
- CONICET - Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina
| | - Martin Stortz
- CONICET - Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina.,Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Buenos Aires, Argentina
| | - Alejandra Guberman
- CONICET - Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina. .,Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología y Biología Molecular y Celular, Buenos Aires, Argentina.
| | - Valeria Levi
- CONICET - Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Instituto de Química Biológica (IQUIBICEN), Buenos Aires, Argentina.
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7
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White MD, Zenker J, Bissiere S, Plachta N. Instructions for Assembling the Early Mammalian Embryo. Dev Cell 2018; 45:667-679. [DOI: 10.1016/j.devcel.2018.05.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 01/23/2018] [Accepted: 05/10/2018] [Indexed: 12/15/2022]
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White MD, Zhao ZW, Plachta N. In Vivo Imaging of Single Mammalian Cells in Development and Disease. Trends Mol Med 2018; 24:278-293. [PMID: 29439932 DOI: 10.1016/j.molmed.2018.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/05/2018] [Accepted: 01/14/2018] [Indexed: 12/14/2022]
Abstract
Live imaging has transformed biomedical sciences by enabling visualization and analysis of dynamic cellular processes as they occur in their native contexts. Here, we review key recent efforts applying in vivo optical imaging with single-cell resolution to mammalian systems ranging from embryos to adult tissues and organs. We highlight insights into active processes regulating cell fate and morphogenesis during embryonic development, how neuronal circuitry and non-neuronal cell types contribute to neurological functions, and how novel imaging-based approaches enable the dissection of neurological disorders and cancer with high spatio-temporal resolution. The convergence of technical advancements in accessing, visualizing, and manipulating individual cells provides an unprecedented lens to probe mammalian cellular dynamics in vivo in both physiological and pathological states.
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Affiliation(s)
- Melanie D White
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore; These authors contributed equally to this work
| | - Ziqing W Zhao
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore; These authors contributed equally to this work
| | - Nicolas Plachta
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore.
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9
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Bissiere S, Gasnier M, Alvarez YD, Plachta N. Cell Fate Decisions During Preimplantation Mammalian Development. Curr Top Dev Biol 2017; 128:37-58. [PMID: 29477170 DOI: 10.1016/bs.ctdb.2017.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The early mouse embryo offers a phenomenal system to dissect how changes in the mechanisms controlling cell fate are integrated with morphogenetic events at the single-cell level. New technologies based on live imaging have enabled the discovery of dynamic changes in the regulation of single genes, transcription factors, and epigenetic mechanisms directing early cell fate decision in the early embryo. Here, we review recent progress in linking molecular dynamic events occurring at the level of the single cell in vivo, to some of the key morphogenetic changes regulating early mouse development.
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Affiliation(s)
| | - Maxime Gasnier
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore
| | - Yanina D Alvarez
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore; Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Conicet, Buenos Aires, Argentina
| | - Nicolas Plachta
- Institute of Molecular and Cell Biology, A*STAR, Singapore, Singapore; National University of Singapore, Singapore, Singapore.
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10
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Bentovim L, Harden TT, DePace AH. Transcriptional precision and accuracy in development: from measurements to models and mechanisms. Development 2017; 144:3855-3866. [PMID: 29089359 PMCID: PMC5702068 DOI: 10.1242/dev.146563] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
During development, genes are transcribed at specific times, locations and levels. In recent years, the emergence of quantitative tools has significantly advanced our ability to measure transcription with high spatiotemporal resolution in vivo. Here, we highlight recent studies that have used these tools to characterize transcription during development, and discuss the mechanisms that contribute to the precision and accuracy of the timing, location and level of transcription. We attempt to disentangle the discrepancies in how physicists and biologists use the term ‘precision' to facilitate interactions using a common language. We also highlight selected examples in which the coupling of mathematical modeling with experimental approaches has provided important mechanistic insights, and call for a more expansive use of mathematical modeling to exploit the wealth of quantitative data and advance our understanding of animal transcription. Summary: This Review highlights how high-resolution quantitative tools and theoretical models have formed our current view of the mechanisms determining precision and accuracy in the timing, location and level of transcription in the Drosophila embryo.
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Affiliation(s)
- Lital Bentovim
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Timothy T Harden
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Angela H DePace
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
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11
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Quantifying transcription factor–DNA binding in single cells in vivo with photoactivatable fluorescence correlation spectroscopy. Nat Protoc 2017; 12:1458-1471. [DOI: 10.1038/nprot.2017.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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