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Hepatitis B Virus Core Protein Domains Essential for Viral Capsid Assembly in a Cellular Context. J Mol Biol 2020; 432:3802-3819. [PMID: 32371046 DOI: 10.1016/j.jmb.2020.04.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/25/2020] [Accepted: 04/28/2020] [Indexed: 02/07/2023]
Abstract
Hepatitis B virus (HBV) core protein (HBc) is essential to the formation of the HBV capsid. HBc contains two domains: the N-terminal domain corresponding to residues 1-140 essential to form the icosahedral shell and the C-terminal domain corresponding to a basic and phosphorylated peptide, and required for DNA replication. The role of these two domains for HBV capsid assembly was essentially studied in vitro with HBc purified from mammalian or non-mammalian cell lysates, but their respective role in living cells remains to be clarified. We therefore investigated the assembly of the HBV capsid in Huh7 cells by combining fluorescence lifetime imaging microscopy/Förster's resonance energy transfer, fluorescence correlation spectroscopy and transmission electron microscopy approaches. We found that wild-type HBc forms oligomers early after transfection and at a sub-micromolar concentration. These oligomers are homogeneously diffused throughout the cell. We quantified a stoichiometry ranging from ~170 to ~230 HBc proteins per oligomer, consistent with the visualization of eGFP-containingHBV capsid shaped as native capsid particles by transmission electron microscopy. In contrast, no assembly was observed when HBc-N-terminal domain was expressed. This highlights the essential role of the C-terminal domain to form capsid in mammalian cells. Deletion of either the third helix or of the 124-135 residues of HBc had a dramatic impact on the assembly of the HBV capsid, inducing the formation of mis-assembled oligomers and monomers, respectively. This study shows that our approach using fluorescent derivatives of HBc is an innovative method to investigate HBV capsid formation.
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Sizaire F, Le Marchand G, Pécréaux J, Bouchareb O, Tramier M. Automated screening of AURKA activity based on a genetically encoded FRET biosensor using fluorescence lifetime imaging microscopy. Methods Appl Fluoresc 2020; 8:024006. [PMID: 32032967 DOI: 10.1088/2050-6120/ab73f5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Fluorescence Lifetime Imaging Microscopy (FLIM) is a robust tool to measure Förster Resonance Energy Transfer (FRET) between two fluorescent proteins, mainly when using genetically-encoded FRET biosensors. It is then possible to monitor biological processes such as kinase activity with a good spatiotemporal resolution and accuracy. Therefore, it is of interest to improve this methodology for future high content screening purposes. We here implement a time-gated FLIM microscope that can image and quantify fluorescence lifetime with a higher speed than conventional techniques such as Time-Correlated Single Photon Counting (TCSPC). We then improve our system to perform automatic screen analysis in a 96-well plate format. Moreover, we use a FRET biosensor of AURKA activity, a mitotic kinase involved in several epithelial cancers. Our results show that our system is suitable to measure FRET within our biosensor paving the way to the screening of novel compounds, potentially allowing to find new inhibitors of AURKA activity.
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Affiliation(s)
- Florian Sizaire
- Univ Rennes, CNRS, IGDR (Genetics and Development Institute of Rennes), UMR 6290, F-35000 Rennes, France
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Godet J, Mély Y. Exploring protein-protein interactions with large differences in protein expression levels using FLIM-FRET. Methods Appl Fluoresc 2019; 8:014007. [PMID: 31791032 DOI: 10.1088/2050-6120/ab5dd2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Many molecular processes within a cell are carried out by molecular machines built from a large number of proteins organized by their protein-protein interactions (PPIs). Exploring PPIs in their cellular context is critical to better understand the proteins functions. Förster resonance energy transfer measured by fluorescence lifetime imaging (FLIM-FRET) enables to monitor PPIs and to map their spatial organization in a living cell with high spatial and temporal specificity. But both the accurate measurement and the interpretation of multi-exponential FLIM-FRET data associated to mixtures of interacting and non-interacting proteins are difficult. Here we show that a simple diagram plot can find interesting visualization properties by clustering pixels with similar decay signatures. FLIM diagram plot can be used to provide valuable information about stoichiometry and binding mode in PPIs, even in the presence of large differences in protein expression levels of the different interacting partners. The proposed FLIM diagram plot is a useful visual approach for a more straightforward interpretation of complex lifetime data. This approach was applied for revealing critical features of PPIs in live Pseudomonas aeruginosa.
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Affiliation(s)
- Julien Godet
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, Faculté de pharmacie, Illkirch, France. Groupe Méthode Recherche Clinique, Pôle de Santé Publique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
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El Meshri SE, Boutant E, Mouhand A, Thomas A, Larue V, Richert L, Vivet-Boudou V, Mély Y, Tisné C, Muriaux D, de Rocquigny H. The NC domain of HIV-1 Gag contributes to the interaction of Gag with TSG101. Biochim Biophys Acta Gen Subj 2018; 1862:1421-1431. [PMID: 29571744 DOI: 10.1016/j.bbagen.2018.03.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 02/20/2018] [Accepted: 03/19/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND HIV-1 Gag polyprotein orchestrates the assembly of viral particles. Its C-terminus consists of the nucleocapsid (NC) domain that interacts with RNA, and the p6 domain containing the PTAP motif that binds the cellular ESCRT factor TSG101 and ALIX. Deletion of the NC domain of Gag (GagNC) results in defective Gag assembly, a decrease in virus production and, thus probably affects recruitment of the ESCRT machinery. To investigate the role of GagNC in this recruitment, we analysed its impact on TSG101 and ALIX localisations and interactions in cells expressing Gag. METHODS Cells expressing mCherry-Gag or derivatives, alone or together with eGFP-TSG101 or eGFP-ALIX, were analysed by confocal microscopy and FLIM-FRET. Chemical shift mapping between TSG101-UEV motif and Gag C-terminus was performed by NMR. RESULTS We show that deletion of NC or of its two zinc fingers decreases the amount of Gag-TSG101 interacting complexes in cells. These findings are supported by NMR data showing chemical shift perturbations in the NC domain in- and outside - of the zinc finger elements upon TSG101 binding. The NMR data further identify a large stretch of amino acids within the p6 domain directly interacting with TSG101. CONCLUSION The NC zinc fingers and p6 domain of Gag participate in the formation of the Gag-TSG101 complex and in its cellular localisation. GENERAL SIGNIFICANCE This study illustrates that the NC and p6 domains cooperate in the interaction with TSG101 during HIV-1 budding. In addition, details on the Gag-TSG101 complex were obtained by combining two high resolution biophysical techniques.
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Affiliation(s)
- Salah Edin El Meshri
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74, Route du Rhin, 67401 Illkirch Cedex, France
| | - Emmanuel Boutant
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74, Route du Rhin, 67401 Illkirch Cedex, France
| | - Assia Mouhand
- Laboratoire de Cristallographie et RMN biologiques, UMR 8015, CNRS, Université Paris Descartes, 4 avenue de l'Observatoire, 75006 Paris, France; Laboratoire d'Expression génétique microbienne, IBPC, UMR 8261, CNRS, Université Paris Diderot, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Audrey Thomas
- Membrane Domains and Viral Assembly, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS, UMR9004, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Valéry Larue
- Laboratoire de Cristallographie et RMN biologiques, UMR 8015, CNRS, Université Paris Descartes, 4 avenue de l'Observatoire, 75006 Paris, France
| | - Ludovic Richert
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74, Route du Rhin, 67401 Illkirch Cedex, France
| | - Valérie Vivet-Boudou
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 Rue R. Descartes, 67084 Strasbourg Cedex, France
| | - Yves Mély
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74, Route du Rhin, 67401 Illkirch Cedex, France
| | - Carine Tisné
- Laboratoire de Cristallographie et RMN biologiques, UMR 8015, CNRS, Université Paris Descartes, 4 avenue de l'Observatoire, 75006 Paris, France; Laboratoire d'Expression génétique microbienne, IBPC, UMR 8261, CNRS, Université Paris Diderot, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Delphine Muriaux
- Membrane Domains and Viral Assembly, Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS, UMR9004, 1919 route de Mende, 34293 Montpellier cedex 5, France.
| | - Hugues de Rocquigny
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, 74, Route du Rhin, 67401 Illkirch Cedex, France; Morphogenèse et Antigénicité du VIH et des Virus des Hépatites, Inserm - U1259 MAVIVH, 10 boulevard Tonnellé - BP 3223, 37032 Tours Cedex 1 -, France.
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Shi J, Zhou M, Gong A, Li Q, Wu Q, Cheng GJ, Yang M, Sun Y. Fluorescence Lifetime Imaging of Nanoflares for mRNA Detection in Living Cells. Anal Chem 2016; 88:1979-83. [PMID: 26813157 DOI: 10.1021/acs.analchem.5b03689] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The expression level of tumor-related mRNA can reveal significant information about tumor progression and prognosis, so specific mRNA in cells provides an important approach for biological and disease studies. Here, fluorescence lifetime imaging of nanoflares in living cells was first employed to detect specific intracellular mRNA. We characterized the lifetime changes of the prepared nanoflares before and after the treatment of target mRNA and also compared the results with those of fluorescence intensity-based measurements both intracellularly and extracellularly. The nanoflares released the cy5-modified oligonucleotides and bound to the targets, resulting in a fluorescence lifetime lengthening. This work puts forward another dimension of detecting specific mRNA in cells and can also open new ways for detection of many other biomolecules.
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Affiliation(s)
- Jing Shi
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, People's Republic of China
| | - Ming Zhou
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, People's Republic of China.,Department of Industrial Engineering, Purdue University , 225 South University Street, West Lafayette, Indiana 47907, United States
| | - Aihua Gong
- School of Medicine, Jiangsu University , Zhenjiang, Jiangsu 212013, People's Republic of China
| | - Qijun Li
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, People's Republic of China
| | - Qian Wu
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, People's Republic of China
| | - Gary J Cheng
- Department of Industrial Engineering, Purdue University , 225 South University Street, West Lafayette, Indiana 47907, United States
| | - Mingyang Yang
- State Key Laboratory of Tribology, Tsinghua University , Beijing 100084, People's Republic of China
| | - Yaocheng Sun
- School of Medicine, Jiangsu University , Zhenjiang, Jiangsu 212013, People's Republic of China
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