scholarly journals Functional Analysis of the Human Cytomegalovirus US28 Gene by Insertion Mutagenesis with the Green Fluorescent Protein Gene

1998 ◽  
Vol 72 (10) ◽  
pp. 8158-8165 ◽  
Author(s):  
Jeffrey Vieira ◽  
Thomas J. Schall ◽  
Lawrence Corey ◽  
Adam P. Geballe
Keyword(s):  
Green Fluorescent Protein ◽  
Intracellular Calcium ◽  
Human Cytomegalovirus ◽  
Fluorescent Protein ◽  
Early Gene ◽  
Calcium Flux ◽  
Northern Analysis ◽  
Insertion Mutagenesis ◽  
Infected Cells ◽  
Green Fluorescent

ABSTRACT The protein encoded by the US28 gene of human cytomegalovirus (HCMV) has homology to G protein-coupled receptors (GCR). Previous studies demonstrated that recombinant US28 protein can bind the β class of chemokines (K. Neote, D. DiGregorio, J. Y. Mak, R. Horuk, and T. J. Schall, Cell 72:415–425, 1993) and induce a rise in intracellular calcium after the binding of chemokines (J. L. Gao and P. M. Murphy, J. Biol. Chem. 269:28539–28542, 1994). In order to investigate the function of the US28 protein in virus-infected cells, a recombinant HCMV (HV5.8) was constructed, with the US28 open reading frame disrupted by the insertion of the Escherichia coli gpt gene and the gene for the green fluorescent protein. The US28 gene is not required for growth in human fibroblasts (HF). HF infected with wild-type HCMV bound RANTES at 24 h postinfection and demonstrated an intracellular calcium flux induced by RANTES. In cells infected with HV5.8, RANTES did not bind or induce a calcium flux, demonstrating that US28 is responsible for the β-chemokine binding and induced calcium signaling in HCMV-infected cells. The ability of the US28 gene to bind chemokines was shown to cause a significant reduction in the concentration of RANTES in the medium of infected cells. Northern analysis of RNA from infected cells showed that US28 is an early gene, while US27 (another GCR) is a late gene.

scholarly journals Novel Real-Time Monitoring System for Human Cytomegalovirus- Infected Cells In Vitro That Uses a Green Fluorescent Protein-PML-Expressing Cell Line

2006 ◽  
Vol 50 (8) ◽  
pp. 2806-2813 ◽  
Author(s):  
T. Ueno ◽  
Y. Eizuru ◽  
H. Katano ◽  
T. Kurata ◽  
T. Sata ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Cell Line ◽  
Real Time ◽  
Human Cytomegalovirus ◽  
Hcmv Infection ◽  
Fluorescent Protein ◽  
Clinical Isolates ◽  
Pml Bodies ◽  
Infected Cells ◽  
Green Fluorescent

ABSTRACT Promyelocytic leukemia (PML) bodies are discrete nuclear foci that are intimately associated with many DNA viruses. In human cytomegalovirus (HCMV) infection, the IE1 (for “immediate-early 1”) protein has a marked effect on PML bodies via de-SUMOylation of PML protein. Here, we report a novel real-time monitoring system for HCMV-infected cells using a newly established cell line (SE/15) that stably expresses green fluorescent protein (GFP)-PML protein. In SE/15 cells, HCMV infection causes specific and efficient dispersion of GFP-PML bodies in an IE1-dependent manner, allowing the infected cells to be monitored by fluorescence microscopy without immunostaining. Since a specific change in the detergent solubility of GFP-PML occurs upon infection, the infected cells can be quantified by GFP fluorescence measurement after extraction. With this assay, the inhibitory effects of heparin and neutralizing antibodies were determined in small-scale cultures, indicating its usefulness for screening inhibitory reagents for laboratory virus strains. Furthermore, we established a sensitive imaging assay by counting the number of nuclei containing dispersed GFP-PML, which is applicable for titration of slow-growing clinical isolates. In all strains tested, the virus titers estimated by the GFP-PML imaging assay were well correlated with the plaque-forming cell numbers determined in human embryonic lung cells. Coculture of SE/15 cells and HCMV-infected fibroblasts permitted a rapid and reliable method for estimating the 50% inhibitory concentration values of drugs for clinical isolates in susceptibility testing. Taken together, these results demonstrate the development of a rapid, sensitive, quantitative, and specific detection system for HCMV-infected cells involving a simple procedure that can be used for titration of low-titer clinical isolates.

scholarly journals Human Cytomegalovirus Labeled with Green Fluorescent Protein for Live Analysis of Intracellular Particle Movements

2005 ◽  
Vol 79 (5) ◽  
pp. 2754-2767 ◽  
Author(s):  
Kerstin Laib Sampaio ◽  
Yolaine Cavignac ◽  
York-Dieter Stierhof ◽  
Christian Sinzger
Keyword(s):  
Green Fluorescent Protein ◽  
Human Cytomegalovirus ◽  
Fluorescent Protein ◽  
Rare Event ◽  
Single Step ◽  
Wild Type Virus ◽  
Cell Cortex ◽  
Long Distance ◽  
Infected Cells ◽  
Green Fluorescent

ABSTRACT Human cytomegalovirus (HCMV) replicates in the nuclei of infected cells. Successful replication therefore depends on particle movements between the cell cortex and nucleus during entry and egress. To visualize HCMV particles in living cells, we have generated a recombinant HCMV expressing enhanced green fluorescent protein (EGFP) fused to the C terminus of the capsid-associated tegument protein pUL32 (pp150). The resulting UL32-EGFP-HCMV was analyzed by immunofluorescence, electron microscopy, immunoblotting, confocal microscopy, and time-lapse microscopy to evaluate the growth properties of this virus and the dynamics of particle movements. UL32-EGFP-HCMV replicated similarly to wild-type virus in fibroblast cultures. Green fluorescent virus particles were released from infected cells. The fluorescence stayed associated with particles during viral entry, and fluorescent progeny particles appeared in the nucleus at 44 h after infection. Surprisingly, strict colocalization of pUL32 and the major capsid protein pUL86 within nuclear inclusions indicated that incorporation of pUL32 into nascent HCMV particles occurred simultaneously with or immediately after assembly of the capsid. A slow transport of nuclear particles towards the nuclear margin was demonstrated. Within the cytoplasm, most particles performed irregular short-distance movements, while a smaller fraction of particles performed centripetal and centrifugal long-distance movements. Although numerous particles accumulated in the cytoplasm, release of particles from infected cells was a rare event, consistent with a release rate of about 1 infectious unit per h per cell in HCMV-infected fibroblasts as calculated from single-step growth curves. UL32-EGFP-HCMV will be useful for further investigations into the entry, maturation, and release of this virus.

scholarly journals Recombinant Green Fluorescent Protein-Expressing Human Cytomegalovirus as a Tool for Screening Antiviral Agents

2000 ◽  
Vol 44 (6) ◽  
pp. 1588-1597 ◽  
Author(s):  
Manfred Marschall ◽  
Martina Freitag ◽  
Sigrid Weiler ◽  
Gabriele Sorg ◽  
Thomas Stamminger
Keyword(s):  
Green Fluorescent Protein ◽  
Human Cytomegalovirus ◽  
Fluorescent Protein ◽  
Antiviral Agents ◽  
Inhibitory Effects ◽  
Plaque Reduction Assay ◽  
Human Fibroblast Cultures ◽  
Antiviral Activities ◽  
Green Fluorescent

ABSTRACT A recombinant human cytomegalovirus (AD169-GFP) expressing green fluorescent protein was generated by homologous recombination. Infection of human fibroblast cultures with AD169-GFP virus produced stable and readily detectable amounts of GFP signals which were quantitated by automated fluorometry. Hereby, high levels of sensitivity and reproducibility could be achieved, compared to those with the conventional plaque reduction assay. Antiviral activities were determined for four reference compounds as well as a set of putative novel cytomegalovirus inhibitors. The results obtained were exactly in line with the known characteristics of reference compounds and furthermore revealed distinct antiviral activities of novel in vitro inhibitors. The fluorometric data could be confirmed by GFP-based flow cytometry and fluorescence microscopy. In addition, laboratory virus variants derived from the recombinant AD169-GFP virus provided further possibilities for study of the characteristics of drug resistance. The GFP-based antiviral assay appeared to be very reliable for measuring virus-inhibitory effects in concentration- and time-dependent fashions and might also be adaptable for high-throughput screenings of cytomegalovirus-specific antiviral agents.

scholarly journals Retrovirus-mediated in vitro gene transfer into chicken male germ line cells

Reproduction ◽  
2007 ◽  
Vol 134 (3) ◽  
pp. 445-453 ◽  
Author(s):  
Jiří Kalina ◽  
Filip Šenigl ◽  
Alena Mičáková ◽  
Jitka Mucksová ◽  
Jana Blažková ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Reporter Gene ◽  
Fluorescent Protein ◽  
Germ Line ◽  
Retroviral Vector ◽  
Male Germ Line ◽  
Testicular Cells ◽  
Infected Cells ◽  
Green Fluorescent ◽  
Transgenic Chickens

Chicken testicular cells, including spermatogonia, transplanted into the testes of recipient cockerels sterilized by repeated γ-irradiation repopulate the seminiferous epithelium and resume the exogenous spermatogenesis. This procedure could be used to introduce genetic modifications into the male germ line and generate transgenic chickens. In this study, we present a successful retroviral infection of chicken testicular cells and consequent transduction of the retroviral vector into the sperm of recipient cockerels. A vesicular stomatitis virus glycoprotein G-pseudotyped recombinant retroviral vector, carrying the enhanced green fluorescent protein reporter gene was applied to the short-term culture of dispersed testicular cells. The efficiency of infection and the viability of infected cells were analyzed by flow cytometry. No significant CpG methylation was detected in the infected testicular cells, suggesting that epigenetic silencing events do not play a role at this stage of germ line development. After transplantation into sterilized recipient cockerels, these retrovirus-infected testicular cells restored exogenous spermatogenesis within 9 weeks with approximately the same efficiency as non-infected cells. Transduction of the reporter gene encoding the green fluorescent protein was detected in the sperms of recipient cockerels with restored spermatogenesis. Our data demonstrate that, similarly as in mouse and rat, the transplantation of retrovirus-infected spermatogonia provides an efficient system to introduce genes into the chicken male germ line.

scholarly journals Green Fluorescent Protein-Tagged Retroviral Envelope Protein for Analysis of Virus-Cell Interactions

2003 ◽  
Vol 77 (10) ◽  
pp. 6070-6075 ◽  
Author(s):  
Dirk Spitzer ◽  
Kurt E. J. Dittmar ◽  
Manfred Rohde ◽  
Hansjörg Hauser ◽  
Dagmar Wirth
Keyword(s):  
Green Fluorescent Protein ◽  
Envelope Protein ◽  
Fluorescent Protein ◽  
Inverse Correlation ◽  
Cell Interactions ◽  
Virus Particles ◽  
Viral Particles ◽  
Infected Cells ◽  
Env Protein ◽  
Green Fluorescent

ABSTRACT Fluorescent retroviral envelope (Env) proteins were developed for direct visualization of viral particles. By fusing the enhanced green fluorescent protein (eGFP) to the N terminus of the amphotropic 4070A envelope protein, extracellular presentation of eGFP was achieved. Viruses incorporated the modified Env protein and efficiently infected cells. We used the GFP-tagged viruses for staining retrovirus receptor-positive cells, thereby circumventing indirect labeling techniques. By generating cells which conditionally expressed the GFP-tagged Env protein, we could confirm an inverse correlation between retroviral Env expression and infectivity (superinfection). eGFP-tagged virus particles are suitable for monitoring the dynamics of virus-cell interactions.

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