scholarly journals Two different genes coding for processable and nonprocessable forms of a viral envelope protein can account for the apparent hormonal stimulation of protein processing in W7MG1 lymphoma cells.

1992 ◽  
Vol 6 (3) ◽  
pp. 459-467
Author(s):  
R M Bedgood ◽  
I Bahner ◽  
D B Kohn ◽  
M R Stallcup
Keyword(s):  
Envelope Protein ◽  
Protein Processing ◽  
Viral Envelope ◽  
Viral Envelope Protein ◽  
Lymphoma Cells ◽  
Hormonal Stimulation ◽  
Stimulation Of

scholarly journals The YXXL Sequences of a Transmembrane Protein of Bovine Leukemia Virus Are Required for Viral Entry and Incorporation of Viral Envelope Protein into Virions

1999 ◽  
Vol 73 (2) ◽  
pp. 1293-1301 ◽  
Author(s):  
Kazunori Inabe ◽  
Masako Nishizawa ◽  
Shigeru Tajima ◽  
Kazuyoshi Ikuta ◽  
Yoko Aida
Keyword(s):  
Viral Entry ◽  
Envelope Protein ◽  
Bovine Leukemia Virus ◽  
Leukemia Virus ◽  
Transient Transfection ◽  
Viral Envelope ◽  
Tyrosine Residue ◽  
Wild Type ◽  
Viral Envelope Protein

ABSTRACT The cytoplasmic domain of an envelope transmembrane glycoprotein (gp30) of bovine leukemia virus (BLV) has two overlapping copies of the (YXXL)2 motif. The N-terminal motif has been implicated in in vitro signal transduction pathways from the external to the intracellular compartment and is also involved in infection and maintenance of high viral loads in sheep that have been experimentally infected with BLV. To determine the role of YXXL sequences in the replication of BLV in vitro, we changed the tyrosine or leucine residues of the N-terminal motif in an infectious molecular clone of BLV, pBLV-IF, to alanine to produce mutated proviruses designated Y487A, L490A, Y498A, L501A, and Y487/498A. Transient transfection of African green monkey kidney COS-1 cells with proviral DNAs that encoded wild-type and mutant sequences revealed that all of the mutated proviral DNAs synthesized mature envelope proteins and released virus particles into the growth medium. However, serial passages of fetal lamb kidney (FLK) cells, which are sensitive to infection with BLV, after transient transfection revealed that mutation of a second tyrosine residue in the N-terminal motif completely prevented the propagation of the virus. Similarly, Y498A and Y487/498A mutant BLV that was produced by the stably transfected COS-1 cells exhibited significantly reduced levels of cell-free virion-mediated transmission. Analysis of the protein compositions of mutant viruses demonstrated that lower levels of envelope protein were incorporated by two of the mutant virions than by wild-type and other mutant virions. Furthermore, a mutation of a second tyrosine residue decreased the specific binding of BLV particles to FLK cells and the capacity for viral penetration. Our data indicate that the YXXL sequences play critical roles in both viral entry and the incorporation of viral envelope protein into the virion during the life cycle of BLV.

scholarly journals West Nile Virus Mosquito Vectors (Diptera: Culicidae) in Germany

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 493 ◽  
Author(s):  
Helge Kampen ◽  
Cora M. Holicki ◽  
Ute Ziegler ◽  
Martin H. Groschup ◽  
Birke Andrea Tews ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Strain ◽  
Envelope Protein ◽  
Protein Gene ◽  
Viral Envelope ◽  
Mosquito Vectors ◽  
Viral Envelope Protein ◽  
West Nile ◽  
Qrt Pcr ◽  
First Time

In 2018, West Nile virus (WNV) broke out for the first time in Germany, with continuation of the epidemic in 2019, involving birds, horses and humans. To identify vectors and characterize the virus, mosquitoes were collected in both years in zoological gardens and on a horse meadow immediately following the diagnosis of disease cases in birds and horses. Mosquitoes were identified and screened for WNV by qRT-PCR, with virus-positive samples being sequenced for the viral envelope protein gene. While no positive mosquitoes were found in 2018, seven mosquito pools tested positive for WNV in 2019 in the Tierpark (Wildlife Park) Berlin. The pools consisted of Cx. pipiens biotype pipiens (n = 5), and a mixture of Cx. p. biotype pipiens and Cx. p. biotype molestus (n = 2), or hybrids of these, and were collected between 13 August and 24 September 2019. The virus strain turned out to be nearly identical to two WNV strains isolated from birds diseased in 2018 in eastern Germany. The findings represent the first demonstration of WNV in mosquitoes in Germany and include the possibility of local overwintering of the virus.

scholarly journals Identification and characterization of a novel envelope protein in Rana grylio virus

2008 ◽  
Vol 89 (8) ◽  
pp. 1866-1872 ◽  
Author(s):  
Zhe Zhao ◽  
Fei Ke ◽  
You-Hua Huang ◽  
Jiu-Gang Zhao ◽  
Jian-Fang Gui ◽  
...  
Keyword(s):  
Western Blot ◽  
Envelope Protein ◽  
Virus Assembly ◽  
Structural Features ◽  
Envelope Proteins ◽  
Current Data ◽  
Viral Envelope ◽  
Viral Envelope Protein ◽  
Infected Cells

Viral envelope proteins have been proposed to play significant roles in virus infection and assembly. In this study, an envelope protein gene, 53R, was cloned and characterized from Rana grylio virus (RGV), a member of the family Iridoviridae. Database searches found its homologues in all sequenced iridoviruses, and sequence alignment revealed several conserved structural features shared by virus capsid or envelope proteins: a myristoylation site, two predicted transmembrane domains and two invariant cysteine residues. Subsequently, RT-PCR and Western blot detection revealed that the transcripts encoding RGV 53R and the protein itself appeared late during infection of fathead minnow cells and that their appearance was blocked by viral DNA replication inhibitor, indicating that RGV 53R is a late expression gene. Moreover, immunofluorescence localization found an association of 53R with virus factories in RGV-infected cells, and this association was further confirmed by expressing a 53R–GFP fusion protein in pEGFP-N3/53R-transfected cells. Furthermore, detergent extraction and Western blot detection confirmed that RGV 53R was associated with virion membrane. Therefore, the current data suggest that RGV 53R is a novel viral envelope protein and that it may play an important role in virus assembly. This is thought to be the first report on a viral envelope protein that is conserved in all sequenced iridoviruses.

scholarly journals Characterization of the VP39 envelope protein from Singapore grouper iridovirus

2015 ◽  
Vol 61 (12) ◽  
pp. 924-937 ◽  
Author(s):  
Honglian Zhang ◽  
Sheng Zhou ◽  
Liqun Xia ◽  
Xiaohong Huang ◽  
Youhua Huang ◽  
...  
Keyword(s):  
Envelope Protein ◽  
Core Gene ◽  
Immunofluorescence Assay ◽  
Current Data ◽  
Viral Envelope ◽  
Economic Losses ◽  
Immunogold Electron Microscopy ◽  
Viral Envelope Protein ◽  
Drug Inhibition

Singapore grouper iridovirus (SGIV) is a major pathogen that causes heavy economic losses to the grouper aquaculture industry in China and Southeast Asian countries. In the present study, a viral envelope protein, VP39, encoded by SGIV ORF39L, was identified and characterized. SGIV ORF39L was found in all sequenced iridoviruses and is now considered to be a core gene of the family Iridoviridae. ORF39L was classified as a late gene during in vitro infection using reverse transcription–polymerase chain reaction, western blotting, and a drug inhibition analysis. An indirect immunofluorescence assay revealed that the VP39 protein was confined to the cytoplasm, especially at viral assembly sites. Western blot and matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry analyses suggested that VP39 is an envelope protein. Immunogold electron microscopy further confirmed that VP39 is a viral envelope protein. Furthermore, a mouse anti-VP39 polyclonal antibody exhibited SGIV-neutralizing activity in vitro, suggesting that VP39 is involved in SGIV infection. Taken together, the current data suggest that VP39 represents a conserved envelope protein of iridoviruses that contributes to viral infection.

scholarly journals Molecular Changes in Dengue Envelope Protein Domain III upon Interaction with Glycosaminoglycans

Pathogens ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 935
Author(s):  
James G. Hyatt ◽  
Sylvain Prévost ◽  
Juliette M. Devos ◽  
Courtney J. Mycroft-West ◽  
Mark A. Skidmore ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Envelope Protein ◽  
Quaternary Structure ◽  
Chondroitin Sulphate ◽  
Viral Envelope ◽  
Protein Domain ◽  
Viral Envelope Protein ◽  
Oligomeric State ◽  
Molecular Changes ◽  
Viral Attachment

Dengue fever is a rapidly emerging vector-borne viral disease with a growing global burden of approximately 390 million new infections per annum. The Dengue virus (DENV) is a flavivirus spread by female mosquitos of the aedes genus, but the mechanism of viral endocytosis is poorly understood at a molecular level, preventing the development of effective transmission blocking vaccines (TBVs). Recently, glycosaminoglycans (GAGs) have been identified as playing a role during initial viral attachment through interaction with the third domain of the viral envelope protein (EDIII). Here, we report a systematic study investigating the effect of a range of biologically relevant GAGs on the structure and oligomeric state of recombinantly generated EDIII. We provide novel in situ biophysical evidence that heparin and chondroitin sulphate C induce conformational changes in EDIII at the secondary structure level. Furthermore, we report the ability of chondroitin sulphate C to bind EDIII and induce higher-order dynamic molecular changes at the tertiary and quaternary structure levels which are dependent on pH, GAG species, and the GAG sulphation state. Lastly, we conducted ab initio modelling of Small Angle Neutron Scattering (SANS) data to visualise the induced oligomeric state of EDIII caused by interaction with chondroitin sulphate C, which may aid in TBV development.

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