scholarly journals Pseudotyping Autographa californica Multicapsid Nucleopolyhedrovirus (AcMNPV): F Proteins from Group II NPVs Are Functionally Analogous to AcMNPV GP64

2002 ◽  
Vol 76 (11) ◽  
pp. 5729-5736 ◽  
Author(s):  
Oliver Lung ◽  
Marcel Westenberg ◽  
Just M. Vlak ◽  
Douwe Zuidema ◽  
Gary W. Blissard
Keyword(s):  
Membrane Fusion ◽  
Envelope Protein ◽  
Protein Gene ◽  
Autographa Californica ◽  
Viral Envelope ◽  
Viral Attachment ◽  
F Protein ◽  
Viral Propagation ◽  
The Family ◽  
Vesicular Stomatitis

ABSTRACT GP64, the major envelope glycoprotein of budded virions of the baculovirus Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), is involved in viral attachment, mediates membrane fusion during virus entry, and is required for efficient virion budding. Thus, GP64 is essential for viral propagation in cell culture and in animals. Recent genome sequences from a number of baculoviruses show that only a subset of closely related baculoviruses have gp64 genes, while other baculoviruses have a recently discovered unrelated envelope protein named F. F proteins from Lymantria dispar MNPV (LdMNPV) and Spodoptera exigua MNPV (SeMNPV) mediate membrane fusion and are therefore thought to serve roles similar to that of GP64. To determine whether F proteins are functionally analogous to GP64 proteins, we deleted the gp64 gene from an AcMNPV bacmid and inserted F protein genes from three different baculoviruses. In addition, we also inserted envelope protein genes from vesicular stomatitis virus (VSV) and Thogoto virus. Transfection of the gp64-null bacmid DNA into Sf9 cells does not generate infectious particles, but this defect was rescued by introducing either the F protein gene from LdMNPV or SeMNPV or the G protein gene from VSV. These results demonstrate that baculovirus F proteins are functionally analogous to GP64. Because baculovirus F proteins appear to be more widespread within the family and are much more divergent than GP64 proteins, gp64 may represent the acquisition of an envelope protein gene by an ancestral baculovirus. The AcMNPV pseudotyping system provides an efficient and powerful method for examining the functions and compatibilities of analogous or orthologous viral envelope proteins, and it could have important biotechnological applications.

scholarly journals GP64 of group I nucleopolyhedroviruses cannot readily rescue infectivity of group II f-null nucleopolyhedroviruses

2008 ◽  
Vol 89 (2) ◽  
pp. 424-431 ◽  
Author(s):  
Marcel Westenberg ◽  
Just M. Vlak
Keyword(s):  
Fusion Protein ◽  
Selective Advantage ◽  
Autographa Californica ◽  
Viral Attachment ◽  
F Protein ◽  
Group I ◽  
The Family ◽  
Protein Group ◽  
Group Ii ◽  
Budded Virus

The genus Nucleopolyhedrovirus (NPV) of the family Baculoviridae can be subdivided phylogenetically into two groups. The same division can be made on the basis of their budded virus (BV) envelope fusion protein. Group I NPVs are characterized by the presence of a GP64-like major envelope fusion protein, which is involved in viral attachment and the fusion of virus and cell membrane, and is required for budding of progeny nucleocapsids. Group II NPVs have an envelope fusion protein unrelated to GP64, named F. In contrast to GP64, F proteins are found in all baculoviruses, but they are not functional as envelope fusion proteins in group I NPVs. Autographa californica multiple NPV (AcMNPV) lacking GP64 can be pseudotyped by the F protein of Spodoptera exigua multiple NPV (SeMNPV), suggesting that F proteins are functionally analogous to GP64. GP64 homologues are thought to have been acquired by group I NPVs during evolution, thereby giving these viruses a selective advantage and obviating the need for a functional F protein. To address this supposition experimentally, attempts were made to pseudotype a group II NPV, SeMNPV, with GP64. Transfection of an f-null SeMNPV bacmid into Se301 cells did not result in the production of infectious BVs. This defect was rescued by insertion of SeMNPV f, but not by insertion of AcMNPV gp64. This suggests that the functional analogy between GP64 and F is not readily reciprocal and that F proteins from group II NPVs may provide additional functions in BV formation that are lacking in the GP64 type of fusion protein.

scholarly journals A Functional F Analogue of Autographa californica Nucleopolyhedrovirus GP64 from the Agrotis segetum Granulovirus

2008 ◽  
Vol 82 (17) ◽  
pp. 8922-8926 ◽  
Author(s):  
Feifei Yin ◽  
Manli Wang ◽  
Ying Tan ◽  
Fei Deng ◽  
Just M. Vlak ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Membrane Fusion ◽  
Plutella Xylostella ◽  
Syncytium Formation ◽  
Low Ph ◽  
Autographa Californica ◽  
Agrotis Segetum ◽  
Induced Membrane ◽  
F Protein ◽  
Autographa Californica Nucleopolyhedrovirus

ABSTRACT The envelope fusion protein F of Plutella xylostella granulovirus is a computational analogue of the GP64 envelope fusion protein of Autographa californica nucleopolyhedrovirus (AcMNPV). Granulovirus (GV) F proteins were thought to be unable to functionally replace GP64 in the AcMNPV pseudotyping system. In the present study the F protein of Agrotis segetum GV (AgseGV) was identified experimentally as the first functional GP64 analogue from GVs. AgseF can rescue virion propagation and infectivity of gp64-null AcMNPV. The AgseF-pseudotyped AcMNPV also induced syncytium formation as a consequence of low-pH-induced membrane fusion.

scholarly journals Characterization of Vesicular Stomatitis Virus Pseudotypes Bearing Essential Entry Glycoproteins gB, gD, gH, and gL of Herpes Simplex Virus 1

2016 ◽  
Vol 90 (22) ◽  
pp. 10321-10328 ◽  
Author(s):  
Henry B. Rogalin ◽  
Ekaterina E. Heldwein
Keyword(s):  
Herpes Simplex ◽  
Membrane Fusion ◽  
Viral Envelope ◽  
Herpes Simplex Virus 1 ◽  
Herpes Simplex Viruses ◽  
Systematic Exploration ◽  
Vesicular Stomatitis ◽  
Simplex Virus ◽  
First Time ◽  
Hsv 1

ABSTRACTHerpes simplex viruses (HSVs) are unusual in that unlike most enveloped viruses, they require at least four entry glycoproteins, gB, gD, gH, and gL, for entry into target cells in addition to a cellular receptor for gD. The dissection of the herpes simplex virus 1 (HSV-1) entry mechanism is complicated by the presence of more than a dozen proteins on the viral envelope. To investigate HSV-1 entry requirements in a simplified system, we generated vesicular stomatitis virus (VSV) virions pseudotyped with HSV-1 essential entry glycoproteins gB, gD, gH, and gL but lacking the native VSV fusogen G. These virions, referred to here as VSVΔG-BHLD virions, infected a cell line expressing a gD receptor, demonstrating for the first time that the four essential entry glycoproteins of HSV-1 are not only required but also sufficient for cell entry. To our knowledge, this is the first time the VSV pseudotyping system has been successfully extended beyond two proteins. Entry of pseudotyped virions required a gD receptor and was inhibited by HSV-1 specific anti-gB or anti-gH/gL neutralizing antibodies, which suggests that membrane fusion during the entry of the pseudotyped virions shares common requirements with the membrane fusion involved in HSV-1 entry and HSV-1-mediated syncytium formation. The HSV pseudotyping system established in this study presents a novel tool for systematic exploration of the HSV entry and membrane fusion mechanisms.IMPORTANCEHerpes simplex viruses (HSVs) are human pathogens that can cause cold sores, genital herpes, and blindness. No vaccines or preventatives are available. HSV entry into cells—a prerequisite for a successful infection—is a complex process that involves multiple viral and host proteins and occurs by different routes. Detailed mechanistic knowledge of the HSV entry is important for understanding its pathogenesis and would benefit antiviral and vaccine development, yet the presence of more than a dozen proteins on the viral envelope complicates the dissection of the HSV entry mechanisms. In this study, we generated heterologous virions displaying the four essential entry proteins of HSV-1 and showed that they are capable of cell entry and, like HSV-1, require all four entry glycoproteins along with a gD receptor. This HSV pseudotyping system pioneered in this work opens doors for future systematic exploration of the herpesvirus entry mechanisms.

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 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.

A Dissection of Steps Leading to Viral Envelope Protein-Mediated Membrane Fusion

1991 ◽  
Vol 635 (1 Calcium Entry) ◽  
pp. 285-296 ◽  
Author(s):  
ROBERT BLUMENTHAL ◽  
CHRISTIAN SCHOCH ◽  
ANU PURI ◽  
MICHAEL J. CLAGUE
Keyword(s):  
Membrane Fusion ◽  
Envelope Protein ◽  
Viral Envelope ◽  
Viral Envelope Protein

scholarly journals Disruption of the Dimer-Dimer Interaction of the Mumps Virus Attachment Protein Head Domain, Aided by an Anion Located at the Interface, Compromises Membrane Fusion Triggering

2019 ◽  
Vol 94 (2) ◽  
Author(s):  
Marie Kubota ◽  
Iori Okabe ◽  
Shin-ichi Nakakita ◽  
Ayako Ueo ◽  
Yuta Shirogane ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Membrane Fusion ◽  
Host Cell ◽  
Receptor Binding ◽  
Mumps Virus ◽  
Viral Envelope ◽  
Attachment Protein ◽  
F Protein ◽  
Virus Attachment ◽  
Head Domain

ABSTRACT Mumps virus (MuV), an enveloped negative-strand RNA virus belonging to the family Paramyxoviridae, enters the host cell through membrane fusion mediated by two viral envelope proteins, an attachment protein hemagglutinin-neuraminidase (MuV-HN) and a fusion (F) protein. However, how the binding of MuV-HN to glycan receptors triggers membrane fusion is not well understood. The crystal structure of the MuV-HN head domain forms a tetramer (dimer of dimers) like other paramyxovirus attachment proteins. In the structure, a sulfate ion (SO42−) was found at the interface between two dimers, which may be replaced by a hydrogen phosphate ion (HPO42−) under physiological conditions. The anion is captured by the side chain of a positively charged arginine residue at position 139 of one monomer each from both dimers. Substitution of alanine or lysine for arginine at this position compromised the fusion support activity of MuV-HN without affecting its cell surface expression, glycan-receptor binding, and interaction with the F protein. Furthermore, the substitution appeared to affect the tetramer formation of the head domain as revealed by blue native-PAGE analysis. These results, together with our previous similar findings with the measles virus attachment protein head domain, suggest that the dimer-dimer interaction within the tetramer may play an important role in triggering membrane fusion during paramyxovirus entry. IMPORTANCE Despite the use of effective live vaccines, mumps outbreaks still occur worldwide. Mumps virus (MuV) infection typically causes flu-like symptoms and parotid gland swelling but sometimes leads to orchitis, oophoritis, and neurological complications, such as meningitis, encephalitis, and deafness. MuV enters the host cell through membrane fusion mediated by two viral proteins, a receptor-binding attachment protein, and a fusion protein, but its detailed mechanism is not fully understood. In this study, we show that the tetramer (dimer of dimers) formation of the MuV attachment protein head domain is supported by an anion located at the interface between two dimers and that the dimer-dimer interaction plays an important role in triggering the activation of the fusion protein and causing membrane fusion. These results not only further our understanding of MuV entry but provide useful information about a possible target for antiviral drugs.

scholarly journals TMPRSS12 Is an Activating Protease for Subtype B Avian Metapneumovirus

2016 ◽  
Vol 90 (24) ◽  
pp. 11231-11246 ◽  
Author(s):  
Bingling Yun ◽  
Yao Zhang ◽  
Yongzhen Liu ◽  
Xiaolu Guan ◽  
Yongqiang Wang ◽  
...  
Keyword(s):  
Viral Replication ◽  
Membrane Fusion ◽  
Serine Protease ◽  
Viral Envelope ◽  
Host Cells ◽  
Protein Cleavage ◽  
Avian Metapneumovirus ◽  
F Protein ◽  
Subtype B ◽  
Transmembrane Serine Protease

ABSTRACTThe entry of avian metapneumovirus (aMPV) into host cells initially requires the fusion of viral and cell membranes, which is exclusively mediated by fusion (F) protein. Proteolysis of aMPV F protein by endogenous proteases of host cells allows F protein to induce membrane fusion; however, these proteases have not been identified. Here, we provide the first evidence that the transmembrane serine protease TMPRSS12 facilitates the cleavage of subtype B aMPV (aMPV/B) F protein. We found that overexpression of TMPRSS12 enhanced aMPV/B F protein cleavage, F protein fusogenicity, and viral replication. Subsequently, knockdown of TMPRSS12 with specific small interfering RNAs (siRNAs) reduced aMPV/B F protein cleavage, F protein fusogenicity, and viral replication. We also found a cleavage motif in the aMPV/B F protein (amino acids 100 and 101) that was recognized by TMPRSS12. The histidine, aspartic acid, and serine residue (HDS) triad of TMPRSS12 was shown to be essential for the proteolysis of aMPV/B F protein via mutation analysis. Notably, we observed TMPRSS12 mRNA expression in target organs of aMPV/B in chickens. Overall, our results indicate that TMPRSS12 is crucial for aMPV/B F protein proteolysis and aMPV/B infectivity and that TMPRSS12 may serve as a target for novel therapeutics and prophylactics for aMPV.IMPORTANCEProteolysis of the aMPV F protein is a prerequisite for F protein-mediated membrane fusion of virus and cell and for aMPV infection; however, the proteases usedin vitroandvivoare not clear. A combination of analyses, including overexpression, knockdown, and mutation methods, demonstrated that the transmembrane serine protease TMPRSS12 facilitated cleavage of subtype B aMPV (aMPV/B) F protein. Importantly, we located the motif in the aMPV/B F protein recognized by TMPRSS12 and the catalytic triad in TMPRSS12 that facilitated proteolysis of the aMPV/B F protein. This is the first report on TMPRSS12 as a protease for proteolysis of viral envelope glycoproteins. Our study will shed light on the mechanism of proteolysis of aMPV F protein and pathogenesis of aMPV.

The variations of virus shape and size in different preparations

1990 ◽  
Vol 48 (3) ◽  
pp. 580-581
Author(s):  
Ding Mingxiao ◽  
Jiao Renjie ◽  
Liang Fengxia ◽  
Zhai Zhonghe
Keyword(s):  
Sindbis Virus ◽  
Viral Envelope ◽  
Host Cells ◽  
Enveloped Viruses ◽  
Viral Attachment ◽  
Cytopathic Effects ◽  
Surface Replica ◽  
Freeze Etching ◽  
Vesicular Stomatitis ◽  
Important Structure

Envelope is a very important structure for viral attachment and entry into the host cell, but it is also a morphologically variable portion of enveloped viruses. Studying the fine structure of enveloped viruses, we noticed that different sample preparations of viruses resulted in the change of viral size and shape to some extent, which we believe was caused by the variation of the viral envelope. Four typical enveloped viruses: IBRV (Infectious Bovine Rhinotracheitis Virus), GPV (Goat Pox Virus), SbV (Sindbis Virus) and VSV (Vesicular Stomatitis Virus) were investigated in our experiments.Host cells infected with IBRV, GPV, SbV and VSV respectively were fixed with 1-5% glutaraldehyde in Hank's buffer when the cytopathic effects appeared in 50-70% of the cells, then the specimens were treated respectively with different conventional methods of EM sample preparation: 1) ultrathin sectioning, 2) negative staining,3) freeze etching, 4) surface replica, 5) whole mount or SEM observations. All the samples were examined under JEM-200CX TEM or JSM-35CF SEM.

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