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Virus Glycoprotein (virus + glycoprotein)
Kinds of Virus Glycoprotein Selected AbstractsPhenotypic analysis of the sensitivity of HIV-1 to inhibitors of the reverse transcriptase, protease, and integrase using a self-inactivating virus vector systemJOURNAL OF MEDICAL VIROLOGY, Issue 3 2001Gergely Jįrmy Abstract Conventional phenotypic analysis of resistance of the human immunodeficiency virus (HIV) to antiviral therapy is time-consuming and requires culture of infectious virus. Although phenotypic analyses may be desirable, rapid generation of test results and decentralized availability of the test system will be important to achieve utility in the clinical practice. This study describes the design of an alternative phenotypic resistance test using replication incompetent viral vectors. Chimeric HIV vectors containing a marker gene were generated. The env and most of the regulatory and accessory genes of HIV were removed. In addition, the 3,U3 region was deleted to obtain a self-inactivating construct. Cotransfection of the plasmid with a plasmid that provided the vesicular stomatitis virus glycoprotein resulted in the production of replication-incompetent virus vectors. Infection of susceptible cells with the vectors led to marker gene expression. Vector production in the presence of protease (PR) inhibitors, or infection in the presence of reverse transcriptase (RT) or integrase (IN) inhibitors reduced marker gene expression in a dose-dependent manner. Marker gene activity was preserved at higher drug levels if vectors contained RT and PR genes from resistant virus isolates. Sensitivity to nucleoside and non-nucleoside RT inhibitors, protease and integrase inhibitors could be determined in 10 working days. The phenotypic drug resistance test using replication-incompetent HIV vectors significantly speeds up drug resistance measurements and allows testing at reduced biosafety levels. This will make clinical use of phenotypic assessment of antiviral resistance more feasible. J. Med. Virol. 64:223,231, 2001. © 2001 Wiley-Liss, Inc. [source] A minor ,-structured conformation is the active state of a fusion peptide of vesicular stomatitis virus glycoprotein,JOURNAL OF PEPTIDE SCIENCE, Issue 4 2008Carolina G. Sarzedas Abstract Entry of enveloped animal viruses into their host cells always depends on a step of membrane fusion triggered by conformational changes in viral envelope glycoproteins. Vesicular stomatitis virus (VSV) infection is mediated by virus spike glycoprotein G, which induces membrane fusion at the acidic environment of the endosomal compartment. In a previous work, we identified a specific sequence in the VSV G protein, comprising the residues 145,164, directly involved in membrane interaction and fusion. In the present work we studied the interaction of pep[145,164] with membranes using NMR to solve the structure of the peptide in two membrane-mimetic systems: SDS micelles and liposomes composed of phosphatidylcholine and phosphatidylserine (PC:PS vesicles). The presence of medium-range NOEs showed that the peptide has a tendency to form N - and C -terminal helical segments in the presence of SDS micelles. Analysis of the chemical shift index indicated helix,coil equilibrium for the C -terminal helix under all conditions studied. At pH 7.0, the N -terminal helix also displayed a helix,coil equilibrium when pep[145-164] was free in solution or in the presence of PC:PS. Remarkably, at the fusogenic pH, the region of the N -terminal helix in the presence of SDS or PC:PS presented a third conformational species that was in equilibrium with the helix and random coil. The N -terminal helix content decreases pH and the minor ,-structured conformation becomes more prevalent at the fusogenic pH. These data point to a ,-conformation as the fusogenic active structure-which is in agreement with the X-ray structure, which shows a ,-hairpin for the region corresponding to pep[145-164]. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] Lentivirus vector-mediated gene transfer to the developing bronchiolar airway epithelium in the fetal lambTHE JOURNAL OF GENE MEDICINE, Issue 6 2007Ze-Yan Yu Abstract Background Development of effective and durable gene therapy for treatment of the respiratory manifestations of cystic fibrosis remains a formidable challenge. Obstacles include difficulty in achieving efficient gene transfer to mature airway epithelium and the need to stably transduce self-renewing epithelial progenitor cells in order to avoid loss of transgene expression through epithelial turnover. Targeting the developing airway epithelium during fetal life offers the prospect of circumventing these challenges. Methods In the current study we investigated vesicular stomatitis virus glycoprotein (VSVg)-pseudotyped HIV-1-derived lentivirus vector-mediated gene transfer to the airway epithelium of mid-gestation fetal lambs, both in vitro and in vivo. In the in vitro studies epithelial sheet explants and lung organ culture were used to examine transduction of the proximal and more distal airway epithelium, respectively. For the in vivo studies, vector was delivered directly into the proximal airway. Results We found that even during the early pseudoglandular and canalicular phases of lung development, occurring through mid-gestation, the proximal bronchial airway epithelium was relatively mature and highly resistant to lentivirus-mediated transduction. In contrast, the more distal bronchiolar airway epithelium was relatively permissive for transduction although the absolute levels achieved remained low. Conclusion This result is promising as the bronchiolar airway epithelium is a major site of pathology in the cystic fibrosis airway, and much higher levels of transduction are likely to be achieved by developing strategies that increase the amount of vector reaching the more distal airway after intratracheal delivery. Copyright © 2007 John Wiley & Sons, Ltd. [source] Rabies virus glycoprotein expression in Drosophila S2 cells: Influence of re-selection on protein expressionBIOTECHNOLOGY JOURNAL, Issue 11 2009Alexandra Souza dos Santos Abstract The aim of this study was to achieve expression of recombinant rabies virus glycoprotein (rRVGP) in Drosophila S2 cells. For this, a cDNA coding for the selection hygromycin antibiotic and the cDNA encoding the RVGP protein under the control of the constitutive actin promoter (Ac) were cloned in an expression plasmid, which was transfected into S2 cells. S2 cell populations (S2AcRVGPHy) showed rRVGP expression in cell lysates, attaining concentrations up to 1.5 ,g/107 cells (705 ,g/L). Of the transfected cells, 20% were shown to express the rRVGP. Cell subpopulations selected by limiting dilution expressed higher rRVGP yields and 90% of the cells were shown to express the rRVGP. Cell populations re-selected by addition of hygromycin were shown to express 10 times higher rRVGP yields. The data presented here show that Drosophila S2 cells can be efficiently transfected with an expression/selection plasmid for rRVGP expression, allowing its synthesis with a high degree of physical and biological integrity. The importance of subpopulation selection was indicated by the increasing rRVGP yields during these procedures. [source] Cytoplasmic tail motifs mediate endoplasmic reticulum localization and export of transmembrane reporters in the protozoan parasite Toxoplasma gondiiCELLULAR MICROBIOLOGY, Issue 6 2000Heinrich C. Hoppe In mammalian cells and yeasts, amino acid motifs in the cytoplasmic tails of transmembrane proteins play a prominent role in protein targeting in the early secretory pathway by mediating localization to or rapid export from the endoplasmic reticulum (ER). However, early sorting events are poorly characterized in protozoan parasites. Here, we show that a C-terminal QKTT sequence mediates the ER localization of chimeric reporter constructs consisting of bacterial alkaline phosphatase (BAP) fused to the transmembrane domain (TMD) and truncated cytoplasmic tail of the human low-density lipoprotein receptor (LDL) receptor or of murine lysosome-associated membrane protein (lamp-1) in Toxoplasma gondii. The cytoplasmic tail of human TGN46 also determines ER localization of BAP chimeras in the parasite, but this can be overcome by the addition at the C-terminus of the tail of an acidic patch, which functions as an ER export signal in conjunction with an upstream tyrosine motif. These results suggest that COPI-dependent ER retrieval and COPII-dependent export mechanisms mediated by KKXX and DXE motifs of mammalian cells are generally conserved in T. gondii. In contrast, the failure of the QKTT motif and TGN46 cytoplasmic tail to induce steady-state ER localization of vesicular stomatitis virus glycoprotein (VSVG) chimeras in HeLa and NRK cells indicates that significant differences in early secretory trafficking also exist. [source] Association of antibodies to hepatitis C virus glycoproteins 1 and 2 (anti-E1E2) with HCV diseaseJOURNAL OF VIRAL HEPATITIS, Issue 5 2008M. R. B. Hamed Summary., Hepatitis C virus (HCV) causes acute and chronic liver diseases in humans. Its two envelope glycoproteins, E1 and E2, provide a target for host immune recognition. HCV genotypes are classified into six genetic groups. To study the role of anti-HCV E1 and E2 (anti-E1E2) in HCV disease, the correlation between antibody level and viral load, genotype, disease severity and response to treatment was investigated. The levels of antibodies to HCV glycoproteins E1 and E2 antibodies were evaluated in 230 sera of patients with chronic hepatitis C by enzyme-linked immunosorbent assay. The antigens used were recombinant HCV glycoproteins derived from genotype 1 (H77c) and genotype 3 (UKN3A1.28). Seroreactivity was greater when sera were tested against antigen derived from their homologous genotype than against heterologous antigen. Reactivity against UKN3A1.28 in sera from patients infected with genotype 3 was significantly higher than corresponding reactivity between patients infected with genotype 1 and H77c. The seroreactivity was inversely proportional to the viral load and to the degree of liver fibrosis. The pre-treatment level of anti-E1E2 was higher in sustained responders to combination therapy. These results demonstrate that seroreactivity against E1E2 depends upon the genotypic origin of the E1E2 antigens and the infecting genotype, and suggest a possible protective effect of anti-E1E2 against disease progression. [source] | ||||||||||