151
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Abstract
The replication cycle of HIV proceeds within an infected cell and imaging techniques allow us to focus on the pathogen in this cellular environment. During recent years, both electron microscopy and fluorescence microscopy have evolved from methods providing two-dimensional still images to techniques that can resolve native, three-dimensional structures at resolutions down to approximately 20 Å, or allow direct real-time observation of dynamic intracellular events, respectively, thereby yielding numerous novel insights into HIV biology. Future technological developments are expected to narrow the gap between electron microscopy (high spatial and structural resolution, but no information about dynamics) and fluorescence microscopy (high temporal resolution and high throughput, but low spatial resolution), providing detailed views that will deepen our understanding of HIV–cell interactions.
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Affiliation(s)
- Barbara Müller
- Department of Infectious Diseases, Virology, University Hospital of Heidelberg, Im Neuenheimer Feld 324, D-69120 Heidelberg, Germany
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152
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Pomorski A, Krężel A. Exploration of biarsenical chemistry--challenges in protein research. Chembiochem 2011; 12:1152-67. [PMID: 21538762 DOI: 10.1002/cbic.201100114] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Indexed: 11/07/2022]
Abstract
The fluorescent modification of proteins (with genetically encoded low-molecular-mass fluorophores, affinity probes, or other chemically active species) is extraordinarily useful for monitoring and controlling protein functions in vitro, as well as in cell cultures and tissues. The large sizes of some fluorescent tags, such as fluorescent proteins, often perturb normal activity and localization of the protein of interest, as well as other effects. Of the many fluorescent-labeling strategies applied to in vitro and in vivo studies, one is very promising. This requires a very short (6- to 12-residue), appropriately spaced, tetracysteine sequence (-CCXXCC-); this is either placed at a protein terminus, within flexible loops, or incorporated into secondary structure elements. Proteins that contain the tetracysteine motif become highly fluorescent upon labeling with a nonluminescent biarsenical probe, and form very stable covalent complexes. We focus on the development, growth, and multiple applications of this protein research methodology, both in vitro and in vivo. Its application is not limited to intact-cell protein visualization; it has tremendous potential in other protein research disciplines, such as protein purification and activity control, electron microscopy imaging of cells or tissue, protein-protein interaction studies, protein stability, and aggregation studies.
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Affiliation(s)
- Adam Pomorski
- Department of Protein Engineering, Faculty of Biotechnology, University of Wrocław, Wrocław, Poland
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153
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Abstract
Viral infection converts the normal functions of a cell to optimize viral replication and virion production. One striking observation of this conversion is the reconfiguration and reorganization of cellular actin, affecting every stage of the viral life cycle, from entry through assembly to egress. The extent and degree of cytoskeletal reorganization varies among different viral infections, suggesting the evolution of myriad viral strategies. In this Review, we describe how the interaction of viral proteins with the cell modulates the structure and function of the actin cytoskeleton to initiate, sustain and spread infections. The molecular biology of such interactions continues to engage virologists in their quest to understand viral replication and informs cell biologists about the role of the cytoskeleton in the uninfected cell.
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154
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Stolp B, Fackler OT. How HIV takes advantage of the cytoskeleton in entry and replication. Viruses 2011; 3:293-311. [PMID: 21994733 PMCID: PMC3185699 DOI: 10.3390/v3040293] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/11/2011] [Accepted: 03/19/2011] [Indexed: 01/08/2023] Open
Abstract
The host cell cytoskeleton plays a key role in the life cycle of viral pathogens whose propagation depends on mandatory intracellular steps. Accordingly, also the human immunodeficiency virus type 1 (HIV-1) has evolved strategies to exploit and modulate in particular the actin cytoskeleton for its purposes. This review will recapitulate recent findings on how HIV-1 hijacks the cytoskeleton to facilitate entry into, transport within and egress from host cells as well as to commandeer communication of infected with uninfected bystander cells.
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Affiliation(s)
- Bettina Stolp
- Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany.
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155
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Jones KL, Smyth RP, Pereira CF, Cameron PU, Lewin SR, Jaworowski A, Mak J. Early events of HIV-1 infection: can signaling be the next therapeutic target? J Neuroimmune Pharmacol 2011; 6:269-83. [PMID: 21373988 DOI: 10.1007/s11481-011-9268-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 02/23/2011] [Indexed: 01/08/2023]
Abstract
Intracellular signaling events are signposts of biological processes, which govern the direction and action of biological activities. Through millions of years of evolution, pathogens, such as viruses, have evolved to hijack host cell machinery to infect their targets and are therefore dependent on host cell signaling for replication. This review will detail our current understanding of the signaling events that are important for the early steps of HIV-1 replication. More specifically, the therapeutic potential of signaling events associated with chemokine coreceptors, virus entry, viral synapses, and post-entry processes will be discussed. We argue that these pathways may represent novel targets for antiviral therapy.
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Affiliation(s)
- Kate L Jones
- Centre for Virology, Burnet Institute, 85 Commercial Road, Melbourne, VIC 3004, Australia
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156
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Pereira CF, Ellenberg PC, Jones KL, Fernandez TL, Smyth RP, Hawkes DJ, Hijnen M, Vivet-Boudou V, Marquet R, Johnson I, Mak J. Labeling of multiple HIV-1 proteins with the biarsenical-tetracysteine system. PLoS One 2011; 6:e17016. [PMID: 21347302 PMCID: PMC3037950 DOI: 10.1371/journal.pone.0017016] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 01/19/2011] [Indexed: 12/01/2022] Open
Abstract
Due to its small size and versatility, the biarsenical-tetracysteine system is an attractive way to label viral proteins for live cell imaging. This study describes the genetic labeling of the human immunodeficiency virus type 1 (HIV-1) structural proteins (matrix, capsid and nucleocapsid), enzymes (protease, reverse transcriptase, RNAse H and integrase) and envelope glycoprotein 120 with a tetracysteine tag in the context of a full-length virus. We measure the impact of these modifications on the natural virus infection and, most importantly, present the first infectious HIV-1 construct containing a fluorescently-labeled nucleocapsid protein. Furthermore, due to the high background levels normally associated with the labeling of tetracysteine-tagged proteins we have also optimized a metabolic labeling system that produces infectious virus containing the natural envelope glycoproteins and specifically labeled tetracysteine-tagged proteins that can easily be detected after virus infection of T-lymphocytes. This approach can be adapted to other viral systems for the visualization of the interplay between virus and host cell during infection.
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Affiliation(s)
- Cândida F. Pereira
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
- Monash Micro Imaging, Monash University, Clayton, Victoria, Australia
- Department of Medicine, Monash University, Clayton, Victoria, Australia
| | - Paula C. Ellenberg
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
- Department of Medicine, Monash University, Clayton, Victoria, Australia
| | - Kate L. Jones
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
| | - Tara L. Fernandez
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
| | - Redmond P. Smyth
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France
| | - David J. Hawkes
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
| | - Marcel Hijnen
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Valérie Vivet-Boudou
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France
| | - Roland Marquet
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France
| | - Iain Johnson
- Life Technologies Corporation, Eugene, Oregon, United States of America
| | - Johnson Mak
- Centre for Virology, Burnet Institute, Melbourne, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- * E-mail:
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157
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Szymanski CJ, Humphries WH, Payne CK. Single particle tracking as a method to resolve differences in highly colocalized proteins. Analyst 2011; 136:3527-33. [PMID: 21283889 DOI: 10.1039/c0an00855a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single particle tracking fluorescence microscopy was used to study two late endosomal proteins, Rab7 and LAMP1, that appear to be highly colocalized in static fluorescence microscopy images. Imaging these proteins simultaneously reveals that Rab7 and LAMP1 undergo periods of separation within the cell. Single particle tracking carried out during these periods of separation shows that Rab7-vesicles have greater velocities, but undergo less efficient transport than LAMP1-vesicles. This research demonstrates the use of single particle tracking as a tool to resolve functional differences in highly colocalized proteins in intact live cells.
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Affiliation(s)
- Craig J Szymanski
- School of Chemistry and Biochemistry and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, Georgia 30332, USA
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158
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Effects of microtubule modulators on HIV-1 infection of transformed and resting CD4 T cells. J Virol 2011; 85:3020-4. [PMID: 21209111 DOI: 10.1128/jvi.02462-10] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have observed fluorescently labeled HIV particles tracking along microtubule networks for nuclear localization. To provide direct evidence for the involvement of microtubules in early steps of HIV infection of human CD4 T cells, we used multiple microtubule modulators such as paclitaxel (originally called taxol; 1 μM), vinblastine (1 and 10 μM), colchicine (10 and 100 μM), and nocodazole (10 and 100 μM) to disturb microtubule networks in transformed and resting CD4 T cells. Although these drugs disrupted microtubule integrity, almost no inhibition of HIV-1 infection was observed. Our results do not appear to support an essential role for microtubules in the initiation of HIV infection of CD4 T cells.
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159
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Khiati A, Chaloin O, Muller S, Tardieu M, Horellou P. Induction of monocyte chemoattractant protein-1 (MCP-1/CCL2) gene expression by human immunodeficiency virus-1 Tat in human astrocytes is CDK9 dependent. J Neurovirol 2010; 16:150-67. [PMID: 20370601 DOI: 10.3109/13550281003735691] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Human immunodeficiency virus-1 (HIV-1) invades the brain early in infection and may cause HIV-associated dementia (HAD), which is characterized by reactive astrocytes, and macrophage and T-cell infiltrates. HIV-1 Tat protein is thought to contribute to HAD by transactivating host genes, such as that encoding monocyte chemoattractant protein-1 (MCP-1/CCL2), although its mechanisms of action are not fully understood. We investigated the molecular pathways involved in Tat-induced MCP-1/CCL2 gene expression in human astrocytes. We found that Tat induced MCP-1/CCL2 synthesis in human astrocytes infected with a lentivirus carrying the gene encoding Tat or treated with a biologically active synthetic Tat protein. The induction of MCP-1/CCL2 was independent of the nuclear factor kappaB (NF-kappaB) classical pathway, but was significantly inhibited by specific cyclin-dependent kinase 9 (cdk9) inhibitors, such as a dominant-negative mutant or siRNA. By contrast, broader-spectrum cdk inhibitors, such as roscovitine, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole (DRB), and flavopiridol, inhibited MCP-1/CCL2 induction by Tat. We also analyzed the effects of roscovitine, DRB, and flavopiridol on Tat-induced HIV-1 long terminal repeat (LTR) expression following the infection of astrocytes and HeLa cells. Astrocytes showed no inhibition by roscovitine, 59% inhibition by DRB, and 80% inhibition by flavopiridol. In control HeLa cells, high levels of inhibition were observed with roscovitine, DRB, and flavopiridol. We have ascertained the direct implication of cdk9 in Tat-induced MCP-1 expression by performing ChIP assay. These results demonstrate that cdk9 is involved in Tat-induced HIV-1 LTR, MCP-1/CCL2 gene expression.
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Affiliation(s)
- Abdelkader Khiati
- INSERM U802 and Université Paris-Sud 11, Faculté de médecine Paris-Sud, Le Kremlin-Bicêtre, France
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160
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Levin JG, Mitra M, Mascarenhas A, Musier-Forsyth K. Role of HIV-1 nucleocapsid protein in HIV-1 reverse transcription. RNA Biol 2010; 7:754-74. [PMID: 21160280 DOI: 10.4161/rna.7.6.14115] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The HIV-1 nucleocapsid protein (NC) is a nucleic acid chaperone, which remodels nucleic acid structures so that the most thermodynamically stable conformations are formed. This activity is essential for virus replication and has a critical role in mediating highly specific and efficient reverse transcription. NC's function in this process depends upon three properties: (1) ability to aggregate nucleic acids; (2) moderate duplex destabilization activity; and (3) rapid on-off binding kinetics. Here, we present a detailed molecular analysis of the individual events that occur during viral DNA synthesis and show how NC's properties are important for almost every step in the pathway. Finally, we also review biological aspects of reverse transcription during infection and the interplay between NC, reverse transcriptase, and human APOBEC3G, an HIV-1 restriction factor that inhibits reverse transcription and virus replication in the absence of the HIV-1 Vif protein.
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Affiliation(s)
- Judith G Levin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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161
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Rohr K, Godinez WJ, Harder N, Wörz S, Mattes J, Tvaruskó W, Eils R. Tracking and quantitative analysis of dynamic movements of cells and particles. Cold Spring Harb Protoc 2010; 2010:pdb.top80. [PMID: 20516188 DOI: 10.1101/pdb.top80] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Understanding complex cellular processes requires investigating the underlying mechanisms within a spatiotemporal context. Although cellular processes are dynamic in nature, most studies in molecular cell biology are based on fixed specimens, for example, using immunocytochemistry or fluorescence in situ hybridization (FISH). However, breakthroughs in fluorescence microscopy imaging techniques, in particular, the discovery of green fluorescent protein (GFP) and its spectral variants, have facilitated the study of a wide range of dynamic processes by allowing nondestructive labeling of target structures in living cells. In addition, the tremendous improvements in spatial and temporal resolution of light microscopes now allow cellular processes to be analyzed in unprecedented detail. These state-of-the-art imaging technologies, however, provide a huge amount of digital image data. To cope with the enormous amount of image data and to extract reproducible as well as quantitative information, computer-based image analysis is required. In this article, we describe methods for computer-based analysis of multidimensional live cell microscopy images and their application to study the dynamics of cells and particles. First, we sketch a general workflow for quantitative analysis of live cell images. Then, we detail computational methods for automatic image analysis comprising image preprocessing, segmentation, registration, tracking, and classification. We conclude with a discussion of quantitative analysis and systems biology.
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162
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Selectivity mechanism of the nuclear pore complex characterized by single cargo tracking. Nature 2010; 467:600-3. [PMID: 20811366 PMCID: PMC2948059 DOI: 10.1038/nature09285] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Accepted: 06/10/2010] [Indexed: 01/10/2023]
Abstract
The nuclear pore complex (NPC) mediates all exchange between the cytoplasm and the nucleus. Small molecules can passively diffuse through the NPC, whereas larger cargos require transport receptors to translocate. How the NPC facilitates the translocation of transport receptor/cargo complexes remains unclear. To investigate this process, we tracked single protein-functionalized quantum dot cargos as they moved through human NPCs. Here we show that import proceeds by successive substeps comprising cargo capture, filtering and translocation, and release into the nucleus. Most quantum dots are rejected at one of these steps and return to the cytoplasm, including very large cargos that abort at a size-selective barrier. Cargo movement in the central channel is subdiffusive and cargos that can bind more transport receptors diffuse more freely. Without Ran GTPase, a critical regulator of transport directionality, cargos still explore the entire NPC, but have a markedly reduced probability of exit into the nucleus, suggesting that NPC entry and exit steps are not equivalent and that the pore is functionally asymmetric to importing cargos. The overall selectivity of the NPC seems to arise from the cumulative action of multiple reversible substeps and a final irreversible exit step.
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163
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Schenkwein D, Turkki V, Kärkkäinen HR, Airenne K, Ylä-Herttuala S. Production of HIV-1 integrase fusion protein-carrying lentiviral vectors for gene therapy and protein transduction. Hum Gene Ther 2010; 21:589-602. [PMID: 20039782 DOI: 10.1089/hum.2009.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lentiviral vectors have broad target cell tropism and efficient machinery to integrate transgenes into the host genome. Modification of these vectors by incorporating heterologous proteins into virions has relied mostly on the fusion of proteins into the HIV-1 accessory protein Vpr. Vpr expression can be harmful for cells and its gene has been deleted from third-generation vector production plasmids. We therefore developed a direct integrase fusion protein strategy as an alternative way to package heterologous proteins into vectors. The method was tested by creating two different integrase fusion proteins, IN-p53 and IN-mCherry, cloned into the 3' end of pol in the packaging plasmid. Lentiviral vectors were produced by conventional methods, using the modified packaging plasmids. Vector-incorporated fusion proteins were correctly processed from Gag-Pol, retained the ability to catalyze transgene integration, and showed fusion protein-specific activity by being fluorescent or inducing apoptosis. Functional third-generation lentiviral vectors containing IN-fusion proteins can thus be produced by standard production protocols independent of Vpr expression. Our results suggest that this packaging method is useful for lentiviral vector-mediated protein transduction, such as intranuclear meganuclease, transposon, or zinc finger protein delivery, intracellular imaging of vector particles, and generation of modified lentiviral vectors that contain both toxic and nontoxic IN-fusion proteins.
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Affiliation(s)
- Diana Schenkwein
- Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Kuopio, FIN-70211 Kuopio, Finland
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164
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Genetically engineered, biarsenically labeled influenza virus allows visualization of viral NS1 protein in living cells. J Virol 2010; 84:7204-13. [PMID: 20463066 DOI: 10.1128/jvi.00203-10] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Real-time fluorescence imaging of viral proteins in living cells provides a valuable means to study virus-host interactions. The challenge of generating replication-competent fluorescent influenza A virus is that the segmented genome does not allow fusion of a fluorescent protein gene to any viral gene. Here, we introduced the tetracysteine (TC) biarsenical labeling system into influenza virus in order to fluorescently label viral protein in the virus life cycle. We generated infectious influenza A viruses bearing a small TC tag (CCPGCC) in the loop/linker regions of the NS1 proteins. In the background of A/Puerto Rico/8/34 (H1N1) (PR8) virus, the TC tag can be inserted into NS1 after amino acid 52 (AA52) (PR8-410), AA79 (PR8-412), or AA102 (PR8-413) or the TC tag can be inserted and replace amino acids 79 to 84 (AA79-84) (PR8-411). Although PR8-410, PR8-411, and PR8-412 viruses are attenuated than the wild-type (WT) virus to some extent in multiple-cycle infection, their growth potential is similar to that of the WT virus during a single cycle of infection, and their NS1 subcellular localization and viral protein synthesis rate are quite similar to those of the WT virus. Furthermore, labeling with membrane-permeable biarsenical dye resulted in fluorescent NS1 protein in the context of virus infection. We could exploit this strategy on NS1 protein of A/Texas/36/91 (H1N1) (Tx91) by successfully rescuing a TC-tagged virus, Tx91-445, which carries the TC tag replacement of AA79-84. The infectivity of Tx91-445 virus was similar to that of WT Tx91 during multiple cycles of replication and a single cycle of replication. The NS1 protein derived from Tx91-445 can be fluorescently labeled in living cells. Finally, with biarsenical labeling, the engineered replication-competent virus allowed us to visualize NS1 protein nuclear import in virus-infected cells in real time.
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165
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Benkhelifa-Ziyyat S, Bucher S, Zanta-Boussif MA, Pasquet J, Danos O. Changes in the accessibility of the HIV-1 Integrase C-terminus in the presence of cellular proteins. Retrovirology 2010; 7:27. [PMID: 20367881 PMCID: PMC2859751 DOI: 10.1186/1742-4690-7-27] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 04/05/2010] [Indexed: 11/10/2022] Open
Abstract
Background Following entry, uncoating, and reverse transcription, a number of cellular proteins become associated with the Human Immunodeficiency Virus type 1 (HIV-1) pre-integration complex (PIC). With the goal of obtaining reagents for the analysis of the HIV-1 PIC composition and localisation, we have constructed functional integrase (IN) and matrix (MA) proteins that can be biotinylated during virus production and captured using streptavidin-coated beads. Results Although the labelled C-terminus allows for the sensitive detection of virion-associated IN, it becomes inaccessible in the presence of cellular proteins. This masking is not dependent on the nature of the tag and does not occur with the tagged MA. It was not observed either with an IN mutant unable to interact with LEDGF/p75, or when LEDGF/p75 was depleted from cells. Conclusion Our observation suggests that a structural rearrangement or oligomerization of the IN protein occurs during the early steps of infection and that this process is related to the presence of LEDGF/p75.
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166
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Li C, Henry E, Mani NK, Tang J, Brochon JC, Deprez E, Xie J. Click Chemistry to Fluorescent Amino Esters: Synthesis and Spectroscopic Studies. European J Org Chem 2010. [DOI: 10.1002/ejoc.201000042] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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167
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Warrilow D, Tachedjian G, Harrich D. Maturation of the HIV reverse transcription complex: putting the jigsaw together. Rev Med Virol 2010; 19:324-37. [PMID: 19750561 DOI: 10.1002/rmv.627] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Upon HIV attachment, fusion and entry into the host cell cytoplasm, the viral core undergoes rearrangement to become the mature reverse transcription complex (RTC). Reduced infectivity of viral deletion mutants of the core proteins, capsid and negative factor (Nef), can be complemented by vesicular stomatitis virus (VSV) pseudotyping suggesting a role for these viral proteins in a common event immediately post-entry. This event may be necessary for correct trafficking of the early complex. Enzymatic activation of the complex occurs either before or during RTC maturation, and may be dependent on the presence of deoxynucleotides in the host cell. The RTC initially becomes enlarged immediately after entry, which is followed by a decrease in its sedimentation rate consistent with core uncoating. Several HIV proteins associated with the RTC and recently identified host-cell proteins are important for reverse transcription while genome-wide siRNA knockdown studies have identified additional host cell factors that may be required for reverse transcription. Determining precisely how these proteins assist the RTC function needs to be addressed.
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Affiliation(s)
- David Warrilow
- Division of Infectious Diseases, Queensland Institute of Medical Research, Brisbane, Queensland 4006, Australia.
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168
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Abstract
For many viruses, the ability to infect eukaryotic cells depends on their transport through the cytoplasm and across the nuclear membrane of the host cell. During this journey, viral contents are biochemically processed into complexes capable of both nuclear penetration and genomic integration. We develop a stochastic model of viral entry that incorporates all relevant aspects of transport, including convection along microtubules, biochemical conversion, degradation, and nuclear entry. Analysis of the nuclear infection probabilities in terms of the transport velocity, degradation, and biochemical conversion rates shows how certain values of key parameters can maximize the nuclear entry probability of the viral material. The existence of such "optimal" infection scenarios depends on the details of the biochemical conversion process and implies potentially counterintuitive effects in viral infection, suggesting new avenues for antiviral treatment. Such optimal parameter values provide a plausible transport-based explanation of the action of restriction factors and of experimentally observed optimal capsid stability. Finally, we propose a new interpretation of how genetic mutations unrelated to the mechanism of drug action may nonetheless confer novel types of overall drug resistance.
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Affiliation(s)
- Maria R. D'Orsogna
- Department of Mathematics, California State University Northridge, Los Angeles, California, United States of America
| | - Tom Chou
- Department of Biomathematics and Department of Mathematics, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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169
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Ingestion of the malaria pigment hemozoin renders human macrophages less permissive to HIV-1 infection. Virology 2009; 395:56-66. [DOI: 10.1016/j.virol.2009.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 07/02/2009] [Accepted: 09/05/2009] [Indexed: 11/18/2022]
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170
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Burckhardt CJ, Greber UF. Virus movements on the plasma membrane support infection and transmission between cells. PLoS Pathog 2009; 5:e1000621. [PMID: 19956678 PMCID: PMC2777510 DOI: 10.1371/journal.ppat.1000621] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
How viruses are transmitted across the mucosal epithelia of the respiratory, digestive, or excretory tracts, and how they spread from cell to cell and cause systemic infections, is incompletely understood. Recent advances from single virus tracking experiments have revealed conserved patterns of virus movements on the plasma membrane, including diffusive motions, drifting motions depending on retrograde flow of actin filaments or actin tail formation by polymerization, and confinement to submicrometer areas. Here, we discuss how viruses take advantage of cellular mechanisms that normally drive the movements of proteins and lipids on the cell surface. A concept emerges where short periods of fast diffusive motions allow viruses to rapidly move over several micrometers. Coupling to actin flow supports directional transport of virus particles during entry and cell-cell transmission, and local confinement coincides with either nonproductive stalling or infectious endocytic uptake. These conserved features of virus-host interactions upstream of infectious entry offer new perspectives for anti-viral interference.
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Affiliation(s)
| | - Urs F. Greber
- Institute of Zoology, University of Zürich, Zürich, Switzerland
- * E-mail:
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171
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Glycoprotein-dependent acidification of vesicular stomatitis virus enhances release of matrix protein. J Virol 2009; 83:12139-50. [PMID: 19776119 DOI: 10.1128/jvi.00955-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To study vesicular stomatitis virus (VSV) entry and uncoating, we generated a recombinant VSV encoding a matrix (M) protein containing a C-terminal tetracysteine Lumio tag (rVSV-ML) that could be fluorescently labeled using biarsenical compounds. Quantitative confocal microscopy showed that there is a transient loss of fluorescence at early times after the initiation of endocytosis of rVSV-ML-Green (rVSV-MLG) virions, which did not occur when cells were treated with bafilomycin A1. The reduction in fluorescence occurred 5 to 10 min postentry, followed by a steady increase in fluorescence intensity from 15 to 60 min postentry. A similar loss of fluorescence was observed in vitro when virions were exposed to acidic pH. The reduction in fluorescence required G protein since "bald" DeltaG-MLG particles did not show a similar loss of fluorescence at low pH. Based on the pH-dependent fluorescence properties of Lumio Green, we hypothesize that the loss of fluorescence of rVSV-MLG virions during virus entry is due to a G ectodomain-dependent acidification of the virion interior. Biochemical analysis indicated that low pH also resulted in an enhancement of M protein dissociation from partially permeabilized, but otherwise intact, wild-type virions. From these data we propose that low-pH conformational changes in G protein promote acidification of the virus interior, which facilitates the release of M from ribonucleoprotein particles during uncoating.
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172
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Abstract
Understanding subcellular dynamic processes governing pathogenic mechanisms is a necessary step towards the development of new drugs and strategies against infectious diseases. Subcellular pathogenic mechanisms, such as viral invasion processes involve highly dynamic nanometric-scale objects and rapid molecular interactions that require the study of individual particle paths. Single-particle tracking methods allow visualizing and characterizing the dynamics of biological objects, and provide a straightforward and accurate means to understand subcellular processes. This review describes a number of particle-tracking methods in time-lapse microscopy sequences and provides examples of using such techniques to investigate mechanisms of host-pathogen interactions.
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Affiliation(s)
- Nicolas Chenouard
- Institut Pasteur, Unité d'Analyse d'Images Quantitative, CNRS URA 2582, Paris, France
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173
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Sletten E, Bertozzi C. Bioorthogonale Chemie - oder: in einem Meer aus Funktionalität nach Selektivität fischen. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200900942] [Citation(s) in RCA: 522] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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174
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Meijering E, Dzyubachyk O, Smal I, van Cappellen WA. Tracking in cell and developmental biology. Semin Cell Dev Biol 2009; 20:894-902. [PMID: 19660567 DOI: 10.1016/j.semcdb.2009.07.004] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 07/10/2009] [Accepted: 07/28/2009] [Indexed: 11/30/2022]
Abstract
The past decade has seen an unprecedented data explosion in biology. It has become evident that in order to take full advantage of the potential wealth of information hidden in the data produced by even a single experiment, visual inspection and manual analysis are no longer adequate. To ensure efficiency, consistency, and completeness in data processing and analysis, computational tools are essential. Of particular importance to many modern live-cell imaging experiments is the ability to automatically track and analyze the motion of objects in time-lapse microscopy images. This article surveys the recent literature in this area. Covering all scales of microscopic observation, from cells, down to molecules, and up to entire organisms, it discusses the latest trends and successes in the development and application of computerized tracking methods in cell and developmental biology.
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Affiliation(s)
- Erik Meijering
- Biomedical Imaging Group Rotterdam, Erasmus MC - University Medical Center Rotterdam, Department of Medical Informatics, P. O. Box 2040, 3000 CA Rotterdam, The Netherlands.
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175
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Physical principles and models describing intracellular virus particle dynamics. Curr Opin Microbiol 2009; 12:439-45. [PMID: 19608455 DOI: 10.1016/j.mib.2009.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 06/15/2009] [Accepted: 06/15/2009] [Indexed: 11/17/2022]
Abstract
Modeling in cellular biology benefits greatly from quantitative analysis that arise from the theory of diffusion and chemical reactions. Recent progress in single particle imaging enables the visualization of viral trajectories evolving in the cytoplasm. Biophysical models and mathematical analysis have been developed to unravel the complexity of single viral trajectories. We review here models of active motion of viruses along the cytoskeleton as well as their diffusion. We present resent efforts to estimate global trafficking properties, such as the probability and the mean time for a viral particle to reach a small nuclear pore. However, most signaling pathways involved in controlling viral motion remain undescribed and should be the goal of future modeling efforts.
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176
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Characterization of the behavior of functional viral genomes during the early steps of human immunodeficiency virus type 1 infection. J Virol 2009; 83:7524-35. [PMID: 19457995 DOI: 10.1128/jvi.00429-09] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Infectious viral DNA constitutes only a small fraction of the total viral DNA produced during retroviral infection, and as such its exact behavior is largely unknown. In the present study, we characterized in detail functional viral DNA produced during the early steps of human immunodeficiency virus type 1 infection by analyzing systematically their kinetics of synthesis and integration in different target cells. In addition, we have compared the functional stability of viral nucleoprotein complexes arrested at their pre-reverse transcription state, and we have attempted to measure the kinetics of loss of capsid proteins from viral complexes through the susceptibility of the early phases of infection to cyclosporine, a known inhibitor of the interaction between viral capsid and cyclophilin A. Overall, our data suggest a model in which loss of capsid proteins from viral complexes and reverse transcription occur concomitantly and in which the susceptibility of target cells to infection results from a competition between the ability of the cellular environment to quickly destabilize viral nucleoprotein complexes and the capability of the virus to escape such targeting by engaging the reverse transcription reaction.
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177
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Affiliation(s)
- Simone Lepper
- Department of Parasitology, Hygiene Institute, University of Heidelberg Medical School, 69120 Heidelberg, Germany
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178
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Thys W, Busschots K, McNeely M, Voet A, Christ F, Debyser Z. LEDGF/p75 and transportin-SR2 are cellular cofactors of HIV integrase and novel targets for antiviral therapy. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/17584310.3.2.171] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The HIV replication cycle is an elaborate interplay between the viral machinery and cellular proteins. In this review we propose that protein–protein interactions between cellular proteins and HIV integrase are new targets for future antiviral therapy. We focus on the early steps of HIV replication, namely viral entry, uncoating, reverse transcription, trafficking, nuclear import and integration, and the host cell proteins involved herein. We then discuss the feasibility of developing small-molecule protein–protein interaction inhibitors as antiviral agents. Next, we review the HIV integrase cofactors described in the literature highlighting two validated cofactors, lens epithelium-derived growth factor/p75 and transportin-SR2, which are discussed in detail. Finally, a speculative viewpoint is given on small-molecule protein–protein interaction inhibitors as future HIV inhibitors.
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Affiliation(s)
- Wannes Thys
- Molecular Medicine, KU Leuven Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
| | - Katrien Busschots
- Molecular Medicine, KU Leuven Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
| | - Melissa McNeely
- Molecular Medicine, KU Leuven Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
| | - Arnout Voet
- Molecular Medicine, KU Leuven Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
| | - Frauke Christ
- Molecular Medicine, KU Leuven Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
| | - Zeger Debyser
- Molecular Medicine, KU Leuven Kapucijnenvoer 33 3000 Leuven, Flanders, Belgium
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179
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Desfarges S, Salin B, Calmels C, Andreola ML, Parissi V, Fournier M. HIV-1 integrase trafficking in S. cerevisiae: a useful model to dissect the microtubule network involvement of viral protein nuclear import. Yeast 2009; 26:39-54. [PMID: 19180639 DOI: 10.1002/yea.1651] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Intracellular transport of karyophilic cargos comprises translocation to the nuclear envelope and subsequent nuclear import. Small cargos such as isolated proteins can reach the nuclear envelope by diffusion but movement of larger structures depends on active translocation, typically using microtubules. Centripetal transport ends at the perinuclear microtubule organizing centre called the spindle pole body (SPB) in yeast. Previously, we found by two hybrids that the karyophilic lentiviral-encoded integrase (IN) interacts with two yeast microtubule-associated proteins, Dyn2p (dynein light chain protein) and Stu2p, a centrosomal protein (de Soultrait et al., 2002). Thus, to investigate the hinge between cytoplasmic retrograde transport and nuclear import, we decided to analyse HIV-1 IN trafficking in yeast as the model, since each of these biological mechanisms is evolutionarily conserved in eukaryotic cells. Here, we found an accumulation of IN at the SPB in yeast via Stu2p colocalization. Disruption of the microtubule network by nocodazole or IN expression in a dynein 2-deficient yeast strain prevented IN accumulation in the nuclear periphery and additionally inhibited IN transport into the nucleus. By mutagenesis, we showed that trafficking of IN towards the SPB requires the C-terminus of the molecule. Taking our findings together, we proposed a model in which IN nuclear import seems to depend on an essential intermediate step in the SPB. We found that Dyn2p and Stu2p play an important role in driving IN toward MTOC and could optimize nuclear entry of the retroviral enzyme. Our results suggest a new hypothesis in keeping with the current HIV-1 intracellular trafficking model.
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Affiliation(s)
- S Desfarges
- Laboratoire Microbiologie Cellulaire et Moléculaire et Pathogénicité, Département 1, UMR 5234-CNRS, Bordeaux, France
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180
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Deterministic and probabilistic approaches for tracking virus particles in time-lapse fluorescence microscopy image sequences. Med Image Anal 2009; 13:325-42. [PMID: 19223219 DOI: 10.1016/j.media.2008.12.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 09/16/2008] [Accepted: 12/04/2008] [Indexed: 11/21/2022]
Abstract
Modern developments in time-lapse fluorescence microscopy enable the observation of a variety of processes exhibited by viruses. The dynamic nature of these processes requires the tracking of viruses over time to explore spatial-temporal relationships. In this work, we developed deterministic and probabilistic approaches for multiple virus tracking in multi-channel fluorescence microscopy images. The deterministic approaches follow a traditional two-step paradigm comprising particle localization based on either the spot-enhancing filter or 2D Gaussian fitting, as well as motion correspondence based on a global nearest neighbor scheme. Our probabilistic approaches are based on particle filters. We describe approaches based on a mixture of particle filters and based on independent particle filters. For the latter, we have developed a penalization strategy that prevents the problem of filter coalescence (merging) in cases where objects lie in close proximity. A quantitative comparison based on synthetic image sequences is carried out to evaluate the performance of our approaches. In total, eight different tracking approaches have been evaluated. We have also applied these approaches to real microscopy images of HIV-1 particles and have compared the tracking results with ground truth obtained from manual tracking. It turns out that the probabilistic approaches based on independent particle filters are superior to the deterministic schemes as well as to the approaches based on a mixture of particle filters.
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181
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Taguchi Y, Shi ZD, Ruddy B, Dorward DW, Greene L, Baron GS. Specific biarsenical labeling of cell surface proteins allows fluorescent- and biotin-tagging of amyloid precursor protein and prion proteins. Mol Biol Cell 2009; 20:233-44. [PMID: 18987338 PMCID: PMC2613110 DOI: 10.1091/mbc.e08-06-0635] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 10/03/2008] [Accepted: 10/29/2008] [Indexed: 01/14/2023] Open
Abstract
Fluorescent tagging is a powerful tool for imaging proteins in living cells. However, the steric effects imposed by fluorescent tags impair the behavior of many proteins. Here, we report a novel technique, Instant with DTT, EDT, And Low temperature (IDEAL)-labeling, for rapid and specific FlAsH-labeling of tetracysteine-tagged cell surface proteins by using prion protein (PrP) and amyloid precursor protein (APP) as models. In prion-infected cells, FlAsH-labeled tetracysteine-tagged PrP converted from the normal isoform (PrPsen) to the disease-associated isoform (PrPres), suggesting minimal steric effects of the tag. Pulse-chase analysis of PrP and APP by fluorescent gel imaging demonstrated the utility of IDEAL labeling in investigating protein metabolism by identifying an as-yet-unrecognized C-terminal fragment (C3) of PrPsen and by characterizing the kinetics of PrPres and APP metabolism. C3 generation and N-terminal truncation of PrPres were inhibited by the anti-prion compound E64, a cysteine protease inhibitor. Surprisingly, E64 did not inhibit the synthesis of new PrPres, providing insight into the mechanism by which E64 reduces steady-state PrPres levels in prion-infected cells. To expand the versatility of tetracysteine tagging, we created new Alexa Fluor- and biotin-conjugated tetracysteine-binding molecules that were applied to imaging PrP endocytosis and ultrastructural localization. IDEAL-labeling extends the use of biarsenical derivatives to extracellular proteins and beyond microscopic imaging.
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Affiliation(s)
| | - Zhen-Dan Shi
- Imaging Probe Development Center, National Heart Lung and Blood Institute, National Institutes of Health, Rockville, MD 20892-3372; and
| | - Brian Ruddy
- Imaging Probe Development Center, National Heart Lung and Blood Institute, National Institutes of Health, Rockville, MD 20892-3372; and
| | - David W. Dorward
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840
| | - Lois Greene
- Laboratory of Cell Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-8017
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182
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Sletten EM, Bertozzi CR. Bioorthogonal chemistry: fishing for selectivity in a sea of functionality. Angew Chem Int Ed Engl 2009; 48:6974-98. [PMID: 19714693 PMCID: PMC2864149 DOI: 10.1002/anie.200900942] [Citation(s) in RCA: 2333] [Impact Index Per Article: 155.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The study of biomolecules in their native environments is a challenging task because of the vast complexity of cellular systems. Technologies developed in the last few years for the selective modification of biological species in living systems have yielded new insights into cellular processes. Key to these new techniques are bioorthogonal chemical reactions, whose components must react rapidly and selectively with each other under physiological conditions in the presence of the plethora of functionality necessary to sustain life. Herein we describe the bioorthogonal chemical reactions developed to date and how they can be used to study biomolecules.
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Affiliation(s)
- Ellen M. Sletten
- Department of Chemistry, University of California, Berkeley, CA 94720 (USA)
| | - Carolyn R. Bertozzi
- Departments of Chemistry and Molecular and Cell Biology and Howard Hughes Medical Institute, University of California and The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (USA), Fax: (+1)510-643-2628
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183
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Lagache T, Dauty E, Holcman D. Quantitative analysis of virus and plasmid trafficking in cells. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:011921. [PMID: 19257083 DOI: 10.1103/physreve.79.011921] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 09/22/2008] [Indexed: 05/27/2023]
Abstract
Intracellular transport of DNA carriers is a fundamental step of gene delivery. By combining both theoretical and numerical approaches we study here single and several viruses and DNA particles trafficking in the cell cytoplasm to a small nuclear pore. We present a physical model to account for certain aspects of cellular organization, starting with the observation that a viral trajectory consists of epochs of pure diffusion and epochs of active transport along microtubules. We define a general degradation rate to describe the limitations of the delivery of plasmid or viral particles to a nuclear pore imposed by various types of direct and indirect hydrolysis activity inside the cytoplasm. By replacing the switching dynamics by a single steady state stochastic description, we obtain estimates for the probability and the mean time for the first one of many particles to go from the cell membrane to a small nuclear pore. Computational simulations confirm that our model can be used to analyze and interpret viral trajectories and estimate quantitatively the success of nuclear delivery.
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Affiliation(s)
- Thibault Lagache
- Département de Mathématiques et de Biologie, Ecole Normale Supérieure, 46 rue d'Ulm 75005 Paris, France
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184
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Abstract
HIV-1 relies on a myriad of interactions with host cell proteins to carry out its life cycle. Traditional biochemical approaches to probe protein-protein interactions are limited in their ability to study the spatial and dynamic interactions that take place in the context of an intact cell. However, issues such as localization and dynamics of interactions between viral and host proteins can be well addressed utilizing fluorescent imaging methods. The past decade has brought about the development of many novel fluorescent imaging techniques which have proved useful to describe the interaction of HIV-1 proteins with the host cell.
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Affiliation(s)
- Cindy M Danielson
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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185
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Integrase and integration: biochemical activities of HIV-1 integrase. Retrovirology 2008; 5:114. [PMID: 19091057 PMCID: PMC2615046 DOI: 10.1186/1742-4690-5-114] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 12/17/2008] [Indexed: 01/12/2023] Open
Abstract
Integration of retroviral DNA is an obligatory step of retrovirus replication because proviral DNA is the template for productive infection. Integrase, a retroviral enzyme, catalyses integration. The process of integration can be divided into two sequential reactions. The first one, named 3'-processing, corresponds to a specific endonucleolytic reaction which prepares the viral DNA extremities to be competent for the subsequent covalent insertion, named strand transfer, into the host cell genome by a trans-esterification reaction. Recently, a novel specific activity of the full length integrase was reported, in vitro, by our group for two retroviral integrases (HIV-1 and PFV-1). This activity of internal cleavage occurs at a specific palindromic sequence mimicking the LTR-LTR junction described into the 2-LTR circles which are peculiar viral DNA forms found during viral infection. Moreover, recent studies demonstrated the existence of a weak palindromic consensus found at the integration sites. Taken together, these data underline the propensity of retroviral integrases for binding symmetrical sequences and give perspectives for targeting specific sequences used for gene therapy.
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186
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Bruce JW, Ahlquist P, Young JAT. The host cell sulfonation pathway contributes to retroviral infection at a step coincident with provirus establishment. PLoS Pathog 2008; 4:e1000207. [PMID: 19008949 PMCID: PMC2576444 DOI: 10.1371/journal.ppat.1000207] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Accepted: 10/15/2008] [Indexed: 11/23/2022] Open
Abstract
The early steps of retrovirus replication leading up to provirus establishment are highly dependent on cellular processes and represent a time when the virus is particularly vulnerable to antivirals and host defense mechanisms. However, the roles played by cellular factors are only partially understood. To identify cellular processes that participate in these critical steps, we employed a high volume screening of insertionally mutagenized somatic cells using a murine leukemia virus (MLV) vector. This approach identified a role for 3′-phosphoadenosine 5′-phosphosulfate synthase 1 (PAPSS1), one of two enzymes that synthesize PAPS, the high energy sulfate donor used in all sulfonation reactions catalyzed by cellular sulfotransferases. The role of the cellular sulfonation pathway was confirmed using chemical inhibitors of PAPS synthases and cellular sulfotransferases. The requirement for sulfonation was mapped to a stage during or shortly after MLV provirus establishment and influenced subsequent gene expression from the viral long terminal repeat (LTR) promoter. Infection of cells by an HIV vector was also shown to be highly dependent on the cellular sulfonation pathway. These studies have uncovered a heretofore unknown regulatory step of retroviral replication, have defined a new biological function for sulfonation in nuclear gene expression, and provide a potentially valuable new target for HIV/AIDS therapy. A genetic screen was used to identify host cell functions important for the replication of retroviruses, including human immunodeficiency viruses. These studies have uncovered a heretofore unexpected role for the cellular sulfonation pathway in an intracellular step of retroviral replication. Through the addition of sulfate groups, this pathway is responsible for modifying and regulating different types of cellular factors including proteins, lipids, carbohydrates and hormones. The role of this pathway was further confirmed by using specific chemical inhibitors. The sulfonation requirement was mapped to a step during viral DNA integration into the host genome that has a subsequent effect upon the level of expression of viral genes. These studies have uncovered a new regulatory mechanism of retroviral replication and suggest that components of the host cell sulfonation pathway might represent attractive targets for antiviral development.
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Affiliation(s)
- James W. Bruce
- Institute for Molecular Virology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Paul Ahlquist
- Institute for Molecular Virology, University of Wisconsin, Madison, Wisconsin, United States of America
- Howard Hughes Medical Institute University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail: (PA); (JATY)
| | - John A. T. Young
- Infectious Disease Laboratory, The Salk Institute for Biological Studies, La Jolla, California, United States of America
- * E-mail: (PA); (JATY)
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187
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König R, Zhou Y, Elleder D, Diamond TL, Bonamy GMC, Irelan JT, Chiang CY, Tu BP, De Jesus PD, Lilley CE, Seidel S, Opaluch AM, Caldwell JS, Weitzman MD, Kuhen KL, Bandyopadhyay S, Ideker T, Orth AP, Miraglia LJ, Bushman FD, Young JA, Chanda SK. Global analysis of host-pathogen interactions that regulate early-stage HIV-1 replication. Cell 2008; 135:49-60. [PMID: 18854154 DOI: 10.1016/j.cell.2008.07.032] [Citation(s) in RCA: 757] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 06/12/2008] [Accepted: 07/18/2008] [Indexed: 12/24/2022]
Abstract
Human Immunodeficiency Viruses (HIV-1 and HIV-2) rely upon host-encoded proteins to facilitate their replication. Here, we combined genome-wide siRNA analyses with interrogation of human interactome databases to assemble a host-pathogen biochemical network containing 213 confirmed host cellular factors and 11 HIV-1-encoded proteins. Protein complexes that regulate ubiquitin conjugation, proteolysis, DNA-damage response, and RNA splicing were identified as important modulators of early-stage HIV-1 infection. Additionally, over 40 new factors were shown to specifically influence the initiation and/or kinetics of HIV-1 DNA synthesis, including cytoskeletal regulatory proteins, modulators of posttranslational modification, and nucleic acid-binding proteins. Finally, 15 proteins with diverse functional roles, including nuclear transport, prostaglandin synthesis, ubiquitination, and transcription, were found to influence nuclear import or viral DNA integration. Taken together, the multiscale approach described here has uncovered multiprotein virus-host interactions that likely act in concert to facilitate the early steps of HIV-1 infection.
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Affiliation(s)
- Renate König
- Infectious & Inflammatory Disease Center, Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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188
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Live cell imaging of the HIV-1 life cycle. Trends Microbiol 2008; 16:580-7. [PMID: 18977142 DOI: 10.1016/j.tim.2008.09.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 09/09/2008] [Accepted: 09/23/2008] [Indexed: 10/21/2022]
Abstract
Technology developed in the past 10 years has dramatically increased the ability of researchers to directly visualize and measure various stages of the HIV type 1 (HIV-1) life cycle. In many cases, imaging-based approaches have filled critical gaps in our understanding of how certain aspects of viral replication occur in cells. Specifically, live cell imaging has allowed a better understanding of dynamic, transient events that occur during HIV-1 replication, including the steps involved in viral fusion, trafficking of the viral nucleoprotein complex in the cytoplasm and even the nucleus during infection and the formation of new virions from an infected cell. In this review, we discuss how researchers have exploited fluorescent microscopy methodologies to observe and quantify these events occurring during the replication of HIV-1 in living cells.
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189
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Abstract
Factors necessary for HIV-1 nuclear import have been sought for many years. Recent reports suggest that TNPO3/Transportin-SR2 binds to HIV-1 integrase and is required for HIV-1 infection of interphase cells.
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Affiliation(s)
- Jeremy Luban
- Department of Microbiology and Molecular Medicine, University of Geneva, CH-1211 Geneva 4, Switzerland.
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190
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High accuracy 3D quantum dot tracking with multifocal plane microscopy for the study of fast intracellular dynamics in live cells. Biophys J 2008; 95:6025-43. [PMID: 18835896 DOI: 10.1529/biophysj.108.140392] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single particle tracking in three dimensions in a live cell environment holds the promise of revealing important new biological insights. However, conventional microscopy-based imaging techniques are not well suited for fast three-dimensional (3D) tracking of single particles in cells. Previously we developed an imaging modality multifocal plane microscopy (MUM) to image fast intracellular dynamics in three dimensions in live cells. Here, we introduce an algorithm, the MUM localization algorithm (MUMLA), to determine the 3D position of a point source that is imaged using MUM. We validate MUMLA through simulated and experimental data and show that the 3D position of quantum dots can be determined over a wide spatial range. We demonstrate that MUMLA indeed provides the best possible accuracy with which the 3D position can be determined. Our analysis shows that MUM overcomes the poor depth discrimination of the conventional microscope, and thereby paves the way for high accuracy tracking of nanoparticles in a live cell environment. Here, using MUM and MUMLA we report for the first time the full 3D trajectories of QD-labeled antibody molecules undergoing endocytosis in live cells from the plasma membrane to the sorting endosome deep inside the cell.
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191
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Brun S, Solignat M, Gay B, Bernard E, Chaloin L, Fenard D, Devaux C, Chazal N, Briant L. VSV-G pseudotyping rescues HIV-1 CA mutations that impair core assembly or stability. Retrovirology 2008; 5:57. [PMID: 18605989 PMCID: PMC2474847 DOI: 10.1186/1742-4690-5-57] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Accepted: 07/07/2008] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The machinery of early HIV-1 replication still remains to be elucidated. Recently the viral core was reported to persist in the infected cell cytoplasm as an assembled particle, giving rise to the reverse transcription complex responsible for the synthesis of proviral DNA and its transport to the nucleus. Numerous studies have demonstrated that reverse transcription of the HIV-1 genome into proviral DNA is tightly dependent upon proper assembly of the capsid (CA) protein into mature cores that display appropriate stability. The functional impact of structural properties of the core in early replicative steps has yet to be determined. RESULTS Here, we show that infectivity of HIV-1 mutants bearing S149A and S178A mutations in CA can be efficiently restored when pseudotyped with vesicular stomatitis virus envelope glycoprotein, that addresses the mutant cores through the endocytic pathway rather than by fusion at the plasma membrane. The mechanisms by which these mutations disrupt virus infectivity were investigated. S149A and S178A mutants were unable to complete reverse transcription and/or produce 2-LTR DNA. Morphological analysis of viral particles and in vitro uncoating assays of isolated cores demonstrated that infectivity defects resulted from disruption of the viral core assembly and stability for S149A and S178A mutants, respectively. Consistent with these results, both mutants failed to saturate TRIM-antiviral restriction activity. CONCLUSION Defects generated at the level of core assembly and stability by S149A and S178A mutations are sensitive to the way of delivery of viral nucleoprotein complexes into the target cell. Addressing CA mutants through the endocytic pathway may compensate for defects generated at the reverse transcription/nuclear import level subsequent to impairment of core assembly or stability.
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Affiliation(s)
- Sonia Brun
- Université Montpellier 1, Centre d'études d'agents Pathogènes et Biotechnologies pour Santé, France.
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192
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Albanese A, Arosio D, Terreni M, Cereseto A. HIV-1 pre-integration complexes selectively target decondensed chromatin in the nuclear periphery. PLoS One 2008; 3:e2413. [PMID: 18545681 PMCID: PMC2398779 DOI: 10.1371/journal.pone.0002413] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 04/15/2008] [Indexed: 12/18/2022] Open
Abstract
Integration of the double-stranded DNA copy of the HIV-1 genome into host chromosomal DNA is a requirement for efficient viral replication. Integration preferentially occurs within active transcription units, however chromosomal site specificity does not correlate with any strong primary sequence. To investigate whether the nuclear architecture may affect viral integration we have developed an experimental system where HIV-1 viral particles can be visualized within the nuclear compartment. Fluorescently labeled HIV-1 virions were engineered by fusing integrase, the viral protein that catalyzes the integration reaction, to fluorescent proteins. Viral tests demonstrate that the infectivity of fluorescent virions, including the integration step, is not altered as compared to wild-type virus. 3-D confocal microscopy allowed a detailed analysis of the spatial and temporal distribution of the pre-integration complexes (PICs) within the nucleus at different moments following infection; the fluorescently labeled PICs preferentially distribute in decondensed areas of the chromatin with a striking positioning in the nuclear periphery, while heterochromatin regions are largely disfavored. These observations provide a first indication of how the nuclear architecture may initially orient the selection of retroviral integration sites.
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Affiliation(s)
- Alberto Albanese
- Laboratory of Molecular Biology Scuola Normale Superiore, Pisa, Italy
- NEST, CNR-INFM and Scuola Normale Superiore, Pisa, Italy
| | - Daniele Arosio
- NEST, CNR-INFM and Scuola Normale Superiore, Pisa, Italy
- * E-mail: (AC); (DA)
| | - Mariaelena Terreni
- Laboratory of Molecular Biology Scuola Normale Superiore, Pisa, Italy
- NEST, CNR-INFM and Scuola Normale Superiore, Pisa, Italy
| | - Anna Cereseto
- Laboratory of Molecular Biology Scuola Normale Superiore, Pisa, Italy
- NEST, CNR-INFM and Scuola Normale Superiore, Pisa, Italy
- * E-mail: (AC); (DA)
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193
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Rajan SS, Liu HY, Vu TQ. Ligand-bound quantum dot probes for studying the molecular scale dynamics of receptor endocytic trafficking in live cells. ACS NANO 2008; 2:1153-1166. [PMID: 19206333 DOI: 10.1021/nn700399e] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Endocytic receptor trafficking is a complex, dynamic process underlying fundamental cell function. An integrated understanding of endocytosis at the level of single or small numbers of ligand bound-receptor complexes inside live cells is currently hampered by technical limitations. Here, we develop and test ligand nerve growth factor-bound quantum dot (NGF-QD) bioconjugates for imaging discrete receptor endocytic events inside live NGF-responsive PC12 cells. Using single particle tracking, QD hybrid gel coimmunoprecipitation, and immuno-colocalization, we illustrate and validate the use of QD-receptor complexes for imaging receptor trafficking at synchronized time points after QD-ligand-receptor binding and internalization (t = 15-150 min). The unique value of these probes is illustrated by new dynamic observations: (1) that endocytosis proceeds at strikingly regulated fashion, and (2) that diffusive and active forms of transport inside cells are rapid and efficient. QDs are powerful intracellular probes that can provide biologists with new capabilities and fresh insight for studying endocytic receptor signaling events, in real time, and at the resolution of single or small numbers of receptors in live cells.
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Affiliation(s)
- Sujata Sundara Rajan
- Department of Biomedical Engineering, Oregon Health & Science University, 3303 SW Bond Avenue, 13B, Portland, Oregon 97239, USA
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194
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Lagache T, Holcman D. Quantifying intermittent transport in cell cytoplasm. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2008; 77:030901. [PMID: 18517320 DOI: 10.1103/physreve.77.030901] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Indexed: 05/26/2023]
Abstract
Active cellular transport is a fundamental mechanism for protein and vesicle delivery, cell cycle, and molecular degradation. Viruses can hijack the transport system and use it to reach the nucleus. Most transport processes consist of intermittent dynamics, where the motion of a particle, such as a virus, alternates between pure Brownian and directed movement along microtubules. In this Rapid Communication, we estimate the mean time for a particle to attach to a microtubule network. This computation leads to a coarse grained equation of the intermittent motion in radial and cylindrical geometries. Finally, by using the degradation activity inside the cytoplasm, we obtain refined asymptotic estimations for the probability and the mean time a virus reaches a small nuclear pore.
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Affiliation(s)
- Thibault Lagache
- Department of Biology, Ecole Normale Supérieure, 46 rue d'Ulm 75005 Paris, France
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195
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Renaud O, Viña J, Yu Y, Machu C, Trouvé A, Van der Voort H, Chalmond B, Shorte SL. High-resolution 3-D imaging of living cells in suspension using confocal axial tomography. Biotechnol J 2008; 3:53-62. [PMID: 18022857 DOI: 10.1002/biot.200700188] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Conventional flow cytometry (FC) methods report optical signals integrated from individual cells at throughput rates as high as thousands of cells per second. This is further combined with the powerful utility to subsequently sort and/or recover the cells of interest. However, these methods cannot extract spatial information. This limitation has prompted efforts by some commercial manufacturers to produce state-of-the-art commercial flow cytometry systems allowing fluorescence images to be recorded by an imaging detector. Nonetheless, there remains an immediate and growing need for technologies facilitating spatial analysis of fluorescent signals from cells maintained in flow suspension. Here, we report a novel methodological approach to this problem that combines micro-fluidic flow, and microelectrode dielectric-field control to manipulate, immobilize and image individual cells in suspension. The method also offers unique possibilities for imaging studies on cells in suspension. In particular, we report the system's immediate utility for confocal "axial tomography" using micro-rotation imaging and show that it greatly enhances 3-D optical resolution compared with conventional light reconstruction (deconvolution) image data treatment. That the method we present here is relatively rapid and lends itself to full automation suggests its eventual utility for 3-D imaging cytometry.
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Affiliation(s)
- Olivier Renaud
- Institut Pasteur, Plate-forme d'Imagerie Dynamique, Imagopole, Paris, France
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196
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Arhel NJ, Charneau P. Bisarsenical labeling of HIV-1 for real-time fluorescence microscopy. Methods Mol Biol 2008; 485:151-9. [PMID: 19020824 DOI: 10.1007/978-1-59745-170-3_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Imaging studies have benefited from the development of a novel technique for non-destructive labeling of proteins within living cells, based on the use of a reagent called FlAsH-EDT2, a bisarsenical derivative of fluorescein capable of binding with high affinity and specificity to a tetracysteine motif in the protein of interest. This technique has been adapted for the stable, sensitive and specific molecular tagging of HIV-1 IN enabling the tracking of incoming viral particles inside infected living cells. Here we present the experimental steps required for the efficient labeling of HIV-1 IN, namely, molecular insertion of a tetracysteine tag, production of viruses, labeling in vitro of tagged viruses, infection of target cells and visualization of particles by fluorescence microscopy.
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Affiliation(s)
- Nathalie J Arhel
- Virology Department, Institut Pasteur, Molecular Virology and Vectorology Group, Paris, France
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197
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Turville SG, Aravantinou M, Stössel H, Romani N, Robbiani M. Resolution of de novo HIV production and trafficking in immature dendritic cells. Nat Methods 2007; 5:75-85. [PMID: 18059278 DOI: 10.1038/nmeth1137] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 10/25/2007] [Indexed: 11/09/2022]
Abstract
The challenge in observing de novo virus production in human immunodeficiency virus (HIV)-infected dendritic cells (DCs) is the lack of resolution between cytosolic immature and endocytic mature HIV gag protein. To track HIV production, we developed an infectious HIV construct bearing a diothiol-resistant tetracysteine motif (dTCM) at the C terminus of HIV p17 matrix within the HIV gag protein. Using this construct in combination with biarsenical dyes, we observed restricted staining of the dTCM to de novo-synthesized uncleaved gag in the DC cytosol. Co-staining with HIV gag antibodies, reactive to either p17 matrix or p24 capsid, preferentially stained mature virions and thus allowed us to track the virus at distinct stages of its life cycle within DCs and upon transfer to neighboring DCs or T cells. Thus, in staining HIV gag with biarsenical dye system in situ, we characterized a replication-competent virus capable of being tracked preferentially within infected leukocytes and observed in detail the dynamic nature of the HIV production and transfer in primary DCs.
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Affiliation(s)
- Stuart G Turville
- Center for Biomedical Research, Population Council, 1230 York Avenue, New York, New York 10065, USA.
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198
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Arhel N, Charneau P. [Observation of the HIV-1 virus in infected cells using microscopy approaches]. ACTA ACUST UNITED AC 2007; 56:1-3. [PMID: 17897788 DOI: 10.1016/j.patbio.2007.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Accepted: 06/15/2007] [Indexed: 11/30/2022]
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199
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Mirambeau G, Lyonnais S, Coulaud D, Hameau L, Lafosse S, Jeusset J, Borde I, Reboud-Ravaux M, Restle T, Gorelick RJ, Le Cam E. HIV-1 protease and reverse transcriptase control the architecture of their nucleocapsid partner. PLoS One 2007; 2:e669. [PMID: 17712401 PMCID: PMC1940317 DOI: 10.1371/journal.pone.0000669] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Accepted: 06/18/2007] [Indexed: 11/18/2022] Open
Abstract
The HIV-1 nucleocapsid is formed during protease (PR)-directed viral maturation, and is transformed into pre-integration complexes following reverse transcription in the cytoplasm of the infected cell. Here, we report a detailed transmission electron microscopy analysis of the impact of HIV-1 PR and reverse transcriptase (RT) on nucleocapsid plasticity, using in vitro reconstitutions. After binding to nucleic acids, NCp15, a proteolytic intermediate of nucleocapsid protein (NC), was processed at its C-terminus by PR, yielding premature NC (NCp9) followed by mature NC (NCp7), through the consecutive removal of p6 and p1. This allowed NC co-aggregation with its single-stranded nucleic-acid substrate. Examination of these co-aggregates for the ability of RT to catalyse reverse transcription showed an effective synthesis of double-stranded DNA that, remarkably, escaped from the aggregates more efficiently with NCp7 than with NCp9. These data offer a compelling explanation for results from previous virological studies that focused on i) Gag processing leading to nucleocapsid condensation, and ii) the disappearance of NCp7 from the HIV-1 pre-integration complexes. We propose that HIV-1 PR and RT, by controlling the nucleocapsid architecture during the steps of condensation and dismantling, engage in a successive nucleoprotein-remodelling process that spatiotemporally coordinates the pre-integration steps of HIV-1. Finally we suggest that nucleoprotein remodelling mechanisms are common features developed by mobile genetic elements to ensure successful replication.
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Affiliation(s)
- Gilles Mirambeau
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
- Division de Biochimie, UFR des Sciences de la Vie, Université Pierre et Marie Curie-Paris, Paris, France
- * To whom correspondence should be addressed. E-mail: (GM); (ELC)
| | - Sébastien Lyonnais
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Dominique Coulaud
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Laurence Hameau
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Sophie Lafosse
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Josette Jeusset
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Isabelle Borde
- Laboratoire Biologie et Multimedia, Université Pierre et Marie Curie-Paris, Paris, France
| | - Michèle Reboud-Ravaux
- Laboratoire d'Enzymologie Moléculaire et Fonctionnelle, CNRS FRE 2852, Institut Jacques Monod, CNRS-Université Pierre et Marie Curie-Paris, Paris, France
| | - Tobias Restle
- Institut für Molekulare Medizin, Universitätsklinikum Schleswig-Holstein and ZMSB, Lübeck, Germany
| | - Robert J. Gorelick
- AIDS Vaccine Program, Basic Research Program, Science Applications International Corporation at Frederick, The National Cancer Institute at Frederick, Frederick, Maryland, United States of America
| | - Eric Le Cam
- Laboratoire de Microscopie Moléculaire, UMR 8126: Interactions moléculaires et cancer, CNRS, Université Paris Sud-Institut de Cancérologie Gustave Roussy, Villejuif, France
- * To whom correspondence should be addressed. E-mail: (GM); (ELC)
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200
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Lu PJ, Sims PA, Oki H, Macarthur JB, Weitz DA. Target-locking acquisition with real-time confocal (TARC) microscopy. OPTICS EXPRESS 2007; 15:8702-12. [PMID: 19547205 DOI: 10.1364/oe.15.008702] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We present a real-time target-locking confocal microscope that follows an object moving along an arbitrary path, even as it simultaneously changes its shape, size and orientation. This Target-locking Acquisition with Realtime Confocal (TARC) microscopy system integrates fast image processing and rapid image acquisition using a Nipkow spinning-disk confocal microscope. The system acquires a 3D stack of images, performs a full structural analysis to locate a feature of interest, moves the sample in response, and then collects the next 3D image stack. In this way, data collection is dynamically adjusted to keep a moving object centered in the field of view. We demonstrate the system's capabilities by target-locking freely-diffusing clusters of attractive colloidal particles, and activelytransported quantum dots (QDs) endocytosed into live cells free to move in three dimensions, for several hours. During this time, both the colloidal clusters and live cells move distances several times the length of the imaging volume.
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