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van Belle GJ, Zieseniss A, Heidenreich D, Olmos M, Zhuikova A, Möbius W, Paul MW, Katschinski DM. Cargo-specific effects of hypoxia on clathrin-mediated trafficking. Pflugers Arch 2024:10.1007/s00424-024-02911-6. [PMID: 38294517 DOI: 10.1007/s00424-024-02911-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 12/18/2023] [Accepted: 01/11/2024] [Indexed: 02/01/2024]
Abstract
Clathrin-associated trafficking is a major mechanism for intracellular communication, as well as for cells to communicate with the extracellular environment. A decreased oxygen availability termed hypoxia has been described to influence this mechanism in the past. Mostly biochemical studies were applied in these analyses, which miss spatiotemporal information. We have applied live cell microscopy and a newly developed analysis script in combination with a GFP-tagged clathrin-expressing cell line to obtain insight into the dynamics of the effect of hypoxia. Number, mobility and directionality of clathrin-coated vesicles were analysed in non-stimulated cells as well as after stimulation with epidermal growth factor (EGF) or transferrin in normoxic and hypoxic conditions. These data reveal cargo-specific effects, which would not be observable with biochemical methods or with fixed cells and add to the understanding of cell physiology in hypoxia. The stimulus-dependent consequences were also reflected in the final cellular output, i.e. decreased EGF signaling and in contrast increased iron uptake in hypoxia.
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Affiliation(s)
- Gijsbert J van Belle
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg-August University, 37073, Göttingen, Germany
| | - Anke Zieseniss
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg-August University, 37073, Göttingen, Germany
| | - Doris Heidenreich
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg-August University, 37073, Göttingen, Germany
| | - Maxime Olmos
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg-August University, 37073, Göttingen, Germany
| | - Asia Zhuikova
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg-August University, 37073, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Electron Microscopy, City Campus, Max-Planck-Institute for Multidisciplinary Sciences, 37075, Göttingen, Germany
| | - Maarten W Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Dörthe M Katschinski
- Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg-August University, 37073, Göttingen, Germany.
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2
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Heemskerk T, van de Kamp G, Essers J, Kanaar R, Paul MW. Multi-scale cellular imaging of DNA double strand break repair. DNA Repair (Amst) 2023; 131:103570. [PMID: 37734176 DOI: 10.1016/j.dnarep.2023.103570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/23/2023]
Abstract
Live-cell and high-resolution fluorescence microscopy are powerful tools to study the organization and dynamics of DNA double-strand break repair foci and specific repair proteins in single cells. This requires specific induction of DNA double-strand breaks and fluorescent markers to follow the DNA lesions in living cells. In this review, where we focused on mammalian cell studies, we discuss different methods to induce DNA double-strand breaks, how to visualize and quantify repair foci in living cells., We describe different (live-cell) imaging modalities that can reveal details of the DNA double-strand break repair process across multiple time and spatial scales. In addition, recent developments are discussed in super-resolution imaging and single-molecule tracking, and how these technologies can be applied to elucidate details on structural compositions or dynamics of DNA double-strand break repair.
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Affiliation(s)
- Tim Heemskerk
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Gerarda van de Kamp
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Jeroen Essers
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Vascular Surgery, Erasmus University Medical Center, Rotterdam, the Netherlands; Department of Radiotherapy, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Roland Kanaar
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Maarten W Paul
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, the Netherlands.
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3
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Lerner CA, Gerencser AA. Unbiased Millivolts Assay of Mitochondrial Membrane Potential in Intact Cells. Methods Mol Biol 2022; 2497:11-61. [PMID: 35771433 DOI: 10.1007/978-1-0716-2309-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The mitochondrial membrane potential (ΔψM) is the major component of the bioenergetic driving force responsible for most cellular ATP produced, and it controls a host of biological processes. In intact cells, assay readouts with commonly used fluorescence ΔψM probes are distorted by factors other than ΔψM. Here, we describe a protocol to calculate both ΔψM and plasma membrane potential (ΔψP) in absolute millivolts in intact single cells, or in populations of adherent, cultured cells. Our approach generates unbiased data that allows comparison of ΔψM between cell types with different geometry and ΔψP, and to follow ΔψM in time when ΔψP fluctuates. The experimental paradigm results in fluorescence microscopy time courses using a pair of cationic and anionic probes with internal calibration points that are subsequently computationally converted to millivolts on an absolute scale. The assay is compatible with wide field, confocal or two-photon microscopy. The method given here is optimized for a multiplexed, partial 96-well microplate format to record ΔψP and ΔψM responses for three consecutive treatment additions.
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4
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Mills E, Petersen E. Quantification of Microbial Fluorescent Sensors During Live Intracellular Infections. Methods Mol Biol 2022; 2427:119-131. [PMID: 35619030 DOI: 10.1007/978-1-0716-1971-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The interaction of pathogens with their eukaryotic hosts during intracellular growth is critical to many diseases. However, the relative scarcity of pathogen biomolecules versus the abundant host biomolecule concentration can make quantitative evaluation of pathogen intracellular responses difficult. Recent years have seen an explosion in utilization of fluorescent proteins to serve as transcriptional reporters and biosensors for quantification of pathogen responses. Here, we describe a method to establish a fluorescent assay quantifying pathogen behavior during intracellular infection and to quantify these results at a single cell level. The sensitivity of these fluorescent assays permits the live observation of changing pathogen responses, while the ability to measure at a single cell level uncovers subpopulations of pathogens whose existence may be missed during the population-level assays often required to accumulate sufficient pathogen biomolecules for analysis.
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Affiliation(s)
- Erez Mills
- Department of Animal Sciences, Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.
| | - Erik Petersen
- Department of Health Sciences, College of Public Health, East Tennessee State University, Johnson City, TN, USA.
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5
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Elgamal S, Colombo F, Cottini F, Byrd JC, Cocucci E. Imaging intercellular interaction and extracellular vesicle exchange in a co-culture model of chronic lymphocytic leukemia and stromal cells by lattice light-sheet fluorescence microscopy. Methods Enzymol 2020; 645:79-107. [PMID: 33565979 DOI: 10.1016/bs.mie.2020.06.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent advances in live cell imaging allow investigating processes that take place over the entire cell volume with unprecedented time and spatial resolution. Here we describe a protocol to study intercellular communication, including extracellular vesicle exchange, between cancer cells and their microenvironment, using lattice light sheet fluorescence microscopy. While the described protocol is intended to study the interactions between chronic lymphocytic leukemia cells and bone marrow stromal cells, many components of it can be applied to study other cancers of hematopoietic or solid tumor origin, as well as to characterize other modalities of intercellular communication.
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Affiliation(s)
- Sara Elgamal
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States; Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States
| | - Federico Colombo
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH, United States; Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States
| | - Francesca Cottini
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - John C Byrd
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States; Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH, United States; College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States; Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States
| | - Emanuele Cocucci
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH, United States; Comprehensive Cancer Center, The Ohio State University, Columbus, OH, United States.
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6
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Abstract
A key approach to investigating RNA species in live mammalian cells is the ability to label them with fluorescent tags and track their dynamics in the complex cellular environment. The growing appreciation for the diversity of RNAs in nature, especially the roles of small, non-coding RNAs for cell function, calls for development of orthogonal RNA tagging systems. We previously developed Riboglow, a new RNA tagging system that features modular elements and hence the possibility to customize features for each application of choice. Riboglow consists of an RNA tag that is genetically fused to the RNA of interest and a small molecule that binds the RNA tag and elicits a fluorescence light up signal. Here, we present an overview of the Riboglow platform and compare and contrast the system with existing RNA tagging systems. Two step by step protocols for implementation of RNA imaging with Riboglow in live mammalian cells are presented, with special emphasis on guidelines that drive choices for modular elements in the Riboglow platform. Such modular elements include the RNA tag sequence and size, the number of RNA tag repeats per tagged RNA, the fluorescent color of the probe, the identity of the chemical linker in the probe, and the concentration of the probe used in live cells. Together, Riboglow is a new RNA tagging platform that enables robust live cell imaging of RNA dynamics, and this detailed protocol and guidelines for implementation will enable broad usage of Riboglow.
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7
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Pavlou G, Tardieux I. Phenotyping Toxoplasma Invasive Skills by Fast Live Cell Imaging. Methods Mol Biol 2020; 2071:209-220. [PMID: 31758455 DOI: 10.1007/978-1-4939-9857-9_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Host cell invasion by Toxoplasma gondii/T. gondii tachyzoites is an obligate but complex multistep process occurring in second-scale. To capture the dynamic nature of the whole entry process requires fast and high-resolution live cell imaging. Recent advances in T. gondii/host cell genome editing and in quantitative live cell imaging-image acquisition and processing included-provide a systematic way to accurately phenotype T. gondii tachyzoite invasive behaviour and to highlight any variation or default from a standard scenario. Therefore, applying these combined strategies allows gaining deeper insights into the complex mechanisms underlying host cell invasion.
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Affiliation(s)
- Georgios Pavlou
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France
| | - Isabelle Tardieux
- Institute for Advanced Biosciences (IAB), Team Membrane Dynamics of Parasite-Host Cell Interactions, CNRS UMR5309, INSERM U1209, Université Grenoble Alpes, Grenoble, France.
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8
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Ferrada L, Barahona MJ, Salazar K, Vandenabeele P, Nualart F. Vitamin C controls neuronal necroptosis under oxidative stress. Redox Biol 2020; 29:101408. [PMID: 31926631 DOI: 10.1016/j.redox.2019.101408] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/09/2019] [Accepted: 12/11/2019] [Indexed: 12/31/2022] Open
Abstract
Under physiological conditions, vitamin C is the main antioxidant found in the central nervous system and is found in two states: reduced as ascorbic acid (AA) and oxidized as dehydroascorbic acid (DHA). However, under pathophysiological conditions, AA is oxidized to DHA. The oxidation of AA and subsequent production of DHA in neurons are associated with a decrease in GSH concentrations, alterations in glucose metabolism and neuronal death. To date, the endogenous molecules that act as intrinsic regulators of neuronal necroptosis under conditions of oxidative stress are unknown. Here, we show that treatment with AA regulates the expression of pro- and antiapoptotic genes. Vitamin C also regulates the expression of RIPK1/MLKL, whereas the oxidation of AA in neurons induces morphological alterations consistent with necroptosis and MLKL activation. The activation of necroptosis by AA oxidation in neurons results in bubble formation, loss of membrane integrity, and ultimately, cellular explosion. These data suggest that necroptosis is a target for cell death induced by vitamin C.
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9
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Okkelman IA, Foley T, Papkovsky DB, Dmitriev RI. Multi-Parametric Imaging of Hypoxia and Cell Cycle in Intestinal Organoid Culture. Adv Exp Med Biol 2018; 1035:85-103. [PMID: 29080132 DOI: 10.1007/978-3-319-67358-5_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dynamics of oxygenation of tissue and stem cell niches are important for understanding physiological function of the intestine in normal and diseased states. Only a few techniques allow live visualization of tissue hypoxia at cellular level and in three dimensions. We describe an optimized protocol, which uses cell-penetrating O2-sensitive probe, Pt-Glc and phosphorescence lifetime imaging microscopy (PLIM), to analyze O2 distribution in mouse intestinal organoids. Unlike the other indirect and end-point hypoxia stains, or point measurements with microelectrodes, this method provides high-resolution real-time visualization of O2 in organoids. Multiplexing with conventional fluorescent live cell imaging probes such as the Hoechst 33342-based FLIM assay of cell proliferation, and immunofluorescence staining of endogenous proteins, allows analysis of key physiologic parameters under O2 control in organoids. The protocol is useful for gastroenterology and physiology of intestinal tissue, hypoxia research, regenerative medicine, studying host-microbiota interactions and bioenergetics.
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Affiliation(s)
- Irina A Okkelman
- Laboratory of Biophysics and Bioanalysis, School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Tara Foley
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Dmitri B Papkovsky
- Laboratory of Biophysics and Bioanalysis, School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Ruslan I Dmitriev
- Metabolic Imaging Group, School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland.
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10
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Hodges C, Meiners JC. Fluorescence Correlation Spectroscopy on Genomic DNA in Living Cells. Methods Mol Biol 2018; 1814:415-424. [PMID: 29956247 DOI: 10.1007/978-1-4939-8591-3_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fluorescence correlation spectroscopy (FCS) is a powerful technique used to measure diffusion, fluctuations, and other transport processes in biomolecular systems. It is, however, prone to artifacts and subject to considerable experimental difficulties when applied to living cells. In this chapter, we provide protocols to conduct quantitative FCS measurements on DNA inside living eukaryotic and prokaryotic cells. We discuss sample preparation, dye selection and characterization, FCS data acquisition, and data analysis, including a method to com pensate for photobleaching to obtain quantitatively meaningful spectra.
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Affiliation(s)
- Cameron Hodges
- Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
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11
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Abstract
Even though the formation of compact cylindrical chromosomes early during mitosis or meiosis is a prerequisite for the successful segregation of eukaryotic genomes, little is known about the molecular basis of this chromosome condensation process. Here, we describe in detail the protocol for a quantitative chromosome condensation assay in fission yeast cells, which is based on precise time-resolved measurements of the distances between two fluorescently labeled positions on the same chromosome. In combination with an automated computational analysis pipeline, this assay enables the study of various candidate proteins for their roles in regulating genome topology during cell divisions.
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Affiliation(s)
- Christoph Schiklenk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Boryana Petrova
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Christian H Haering
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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12
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Abstract
To complete cell division and to exit from mitosis into the next G1 phase, eukaryotic cells need to inactivate the cyclin-dependent kinase (Cdk) and reverse Cdk-phosphorylation events. In budding yeast mitotic exit depends on the phosphatase Cdc14. During the majority of the cell cycle Cdc14 is sequestered and kept inactive in the nucleolus. Activation of Cdc14 at anaphase onset coincides with its release from the nucleolus into the nucleus and subsequently into the cytoplasm. Here we describe a microscopy method, originally developed in the laboratory of Frederick Cross (Lu and Cross, Cell 141:268-279, 2010), that allows quantifying Cdc14 release in live cells using the open source software FIJI. We adapted this method and show that it is able to distinguish between Cdc14 activation defects caused by mutations in the "cdcFourteen Early Anaphase Release"-(FEAR) and the mitotic exit network (MEN) using slk19∆ and cdc15-1 mutant strains.
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Affiliation(s)
- Gabriel Neurohr
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain.,Massachusetts Institute of Technology (MIT), 500 Main Street, Cambridge, MA, 02139, USA
| | - Manuel Mendoza
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, 08003, Spain. .,Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain.
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13
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Rajan M, Mortusewicz O, Rothbauer U, Hastert FD, Schmidthals K, Rapp A, Leonhardt H, Cardoso MC. Generation of an alpaca-derived nanobody recognizing γ-H2AX. FEBS Open Bio 2015; 5:779-88. [PMID: 26500838 PMCID: PMC4588710 DOI: 10.1016/j.fob.2015.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/09/2015] [Accepted: 09/16/2015] [Indexed: 12/31/2022] Open
Abstract
Post-translational modifications are difficult to visualize in living cells and are conveniently analyzed using antibodies. Single-chain antibody fragments derived from alpacas and called nanobodies can be expressed and bind to the target antigenic sites in living cells. As a proof of concept, we generated and characterized nanobodies against the commonly used biomarker for DNA double strand breaks γ-H2AX. In vitro and in vivo characterization showed the specificity of the γ-H2AX nanobody. Mammalian cells were transfected with fluorescent fusions called chromobodies and DNA breaks induced by laser microirradiation. We found that alternative epitope recognition and masking of the epitope in living cells compromised the chromobody function. These pitfalls should be considered in the future development and screening of intracellular antibody biomarkers.
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Key Words
- Alpaca heavy chain antibodies
- CKM, casein kinase 2 mutant
- Chromobodies
- DNA repair
- ELISA, enzyme linked immunosorbent assay
- FRAP, fluorescence recovery after photobleaching
- GFP, green fluorescent protein
- H2AX, histone H2AX
- HEK293, human embryonic kidney 293 cells
- KLH, keyhole limpet hemocyanin
- Laser microirradiation
- Live cell microscopy
- MDC1, mediator of DNA damage checkpoint-1
- MEF, mouse embryonic fibroblast
- Post-translational modifications
- RFP, red fluorescent protein
- VHH, variable domain of heavy-chain antibody
- XRCC1, X-ray repair cross-complementing protein 1
- siRNA, short interfering RNA
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Affiliation(s)
- Malini Rajan
- Department of Biology, Technische Universitaet Darmstadt, Germany
| | - Oliver Mortusewicz
- Biozentrum, Department of Biology II, Ludwig Maximilians Universitaet Munich, Germany
| | - Ulrich Rothbauer
- Pharmaceutical Biotechnology, Eberhard-Karls University Tuebingen, Germany
| | | | | | - Alexander Rapp
- Department of Biology, Technische Universitaet Darmstadt, Germany
| | - Heinrich Leonhardt
- Biozentrum, Department of Biology II, Ludwig Maximilians Universitaet Munich, Germany
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14
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Ross MW, Mitchell DJ, Cain JC, Blasier KR, Pfister KK. Live cell imaging of cytoplasmic dynein movement in transfected embryonic rat neurons. Methods Cell Biol 2015; 131:253-67. [PMID: 26794518 DOI: 10.1016/bs.mcb.2015.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Live cell imaging of the movement of various membrane-bounded organelle cargos has enhanced our understanding of their function. Eukaryotic cells utilize microtubules and two classes of microtubule-based motor proteins, cytoplasmic dynein and members of the kinesin family, to deliver a variety of membrane-bounded organelles and other cargos to their appropriate locations. In order to better understand the functions and regulation of cytoplasmic dynein, we developed a method to study its location and motility in living cells. The technique takes advantage of the long thin axons of cultured hippocampal neurons. We use calcium phosphate to transfect fluorescent-tagged dynein intermediate chain (IC) subunits (DYNC1I) into cultured neurons. When the ICs are expressed at low levels, they are effective probes for the location of the cytoplasmic dynein complex in axons when living cells are imaged with fluorescence microscopy. The fluorescent subunit probes can be used to identify specific cargos of dynein complexes with different IC isoforms as well as the kinetic properties of cytoplasmic dynein.
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Affiliation(s)
- Mitchell W Ross
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - David J Mitchell
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - John C Cain
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Kiev R Blasier
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - K Kevin Pfister
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
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15
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Abstract
Fluorescence microscopy of live cells has become an integral part of modern cell biology. Fluorescent protein (FP) tags, live cell dyes, and other methods to fluorescently label proteins of interest provide a range of tools to investigate virtually any cellular process under the microscope. The two main experimental challenges in collecting meaningful live cell microscopy data are to minimize photodamage while retaining a useful signal-to-noise ratio and to provide a suitable environment for cells or tissues to replicate physiological cell dynamics. This chapter aims to give a general overview on microscope design choices critical for fluorescence live cell imaging that apply to most fluorescence microscopy modalities and on environmental control with a focus on mammalian tissue culture cells. In addition, we provide guidance on how to design and evaluate FP constructs by spinning disk confocal microscopy.
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Affiliation(s)
- Andreas Ettinger
- Department of Cell and Tissue Biology, University of California, San Francisco, USA
| | - Torsten Wittmann
- Department of Cell and Tissue Biology, University of California, San Francisco, USA
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