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 The F-Like Protein Ac23 Enhances the Infectivity of the Budded Virus of gp64-Null Autographa californica Multinucleocapsid Nucleopolyhedrovirus Pseudotyped with Baculovirus Envelope Fusion Protein F

2008 ◽  
Vol 82 (19) ◽  
pp. 9800-9804 ◽  
Author(s):  
Manli Wang ◽  
Ying Tan ◽  
Feifei Yin ◽  
Fei Deng ◽  
Just M. Vlak ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Fusion Proteins ◽  
Spodoptera Exigua ◽  
Autographa Californica ◽  
Pseudotyped Virus ◽  
F Protein ◽  
Group I ◽  
Protein F ◽  
Budded Virus ◽  
Functional Envelope

ABSTRACT The GP64 and F proteins were previously identified as the sole functional envelope fusion proteins in Baculoviridae. F-like proteins, present only in group I nucleopolyhedroviruses (NPVs), are remnant, nonfunctional F proteins. In this report, we describe the effect of the presence or absence of the F-like protein Ac23 in a gp64-null Autographa californica multinucleocapsid NPV pseudotyped with the F protein from Spodoptera exigua multicapsid NPV (SeF). We found that the presence of Ac23 elevates the infectivity of the pseudotyped virus. This is in contrast to the results of Lung et al. (J. Virol. 76:5729-5736, 2002), who found no such effect. The possible reasons for the differing results are discussed.

scholarly journals Partial Functional Rescue of Helicoverpa armigera Single Nucleocapsid Nucleopolyhedrovirus Infectivity by Replacement of F Protein with GP64 from Autographa californica Multicapsid Nucleopolyhedrovirus

2010 ◽  
Vol 84 (21) ◽  
pp. 11505-11514 ◽  
Author(s):  
Manli Wang ◽  
Feifei Yin ◽  
Shu Shen ◽  
Ying Tan ◽  
Fei Deng ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Culture Supernatant ◽  
Selective Advantage ◽  
Autographa Californica ◽  
Cell Culture Supernatant ◽  
F Protein ◽  
Group I ◽  
Control Virus ◽  
Helicoverpa Armígera ◽  
Group Ii

ABSTRACT Two distinct envelope fusion proteins (EFPs) (GP64 and F) have been identified in members of the Baculoviridae family of viruses. F proteins are found in group II nucleopolyhedroviruses (NPVs) of alphabaculoviruses and in beta- and deltabaculoviruses, while GP64 occurs only in group I NPVs of alphabaculoviruses. It was proposed that an ancestral baculovirus acquired the gp64 gene that conferred a selective advantage and allowed it to evolve into group I NPVs. The F protein is a functional analogue of GP64, as evidenced from the rescue of gp64-null Autographa californica multicapsid nucleopolyhedrovirus (MNPV) (AcMNPV) by F proteins from group II NPVs or from betabaculoviruses. However, GP64 failed to rescue an F-null Spodoptera exigua MNPV (SeMNPV) (group II NPV). Here, we report the successful generation of an infectious gp64-rescued group II NPV of Helicoverpa armigera (vHaBacΔF-gp64). Viral growth curve assays and quantitative real-time PCR (Q-PCR), however, showed substantially decreased infectivity of vHaBacΔF-gp64 compared to the HaF rescue control virus vHaBacΔF-HaF. Electron microscopy further showed that most vHaBacΔF-gp64 budded viruses (BV) in the cell culture supernatant lacked envelope components and contained morphologically aberrant nucleocapsids, suggesting the improper BV envelopment or budding of vHaBacΔF-gp64. Bioassays using pseudotyped viruses with a reintroduced polyhedrin gene showed that GP64-pseudotyped Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearNPV) significantly delayed the mortality of infected H. armigera larvae.

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 Function, oligomerization and N-linked glycosylation of the Helicoverpa armigera single nucleopolyhedrovirus envelope fusion protein

2006 ◽  
Vol 87 (4) ◽  
pp. 839-846 ◽  
Author(s):  
Gang Long ◽  
Marcel Westenberg ◽  
Hualin Wang ◽  
Just M. Vlak ◽  
Zhihong Hu
Keyword(s):  
Fusion Protein ◽  
Helicoverpa Armigera ◽  
Disulfide Bonds ◽  
Attractive Alternative ◽  
Present Observation ◽  
Reading Frame ◽  
Group I ◽  
The Family ◽  
Helicoverpa Armígera ◽  
Group Ii

In the family Baculoviridae, two distinct envelope fusion proteins are identified in budded virions (BVs). GP64 is the major envelope fusion protein of group I nucleopolyhedrovirus (NPV) BVs. An unrelated type of envelope fusion protein, named F, is encoded by group II NPVs. The genome of Helicoverpa armigera (Hear) NPV, a group II NPV of the single nucleocapsid or S type, also encodes an F-like protein: open reading frame 133 (Ha133). It was demonstrated by N-terminal sequencing of the major 59 kDa protein present in HearNPV BV that this protein is one of the two F subunits: F1 (transmembrane subunit of 59 kDa) and F2 (surface subunit of 20 kDa), both the result of cleavage by a proprotein convertase and disulfide-linked. The HearNPV F protein proved to be a functional analogue of GP64, as the infectivity of an AcMNPV gp64-deletion mutant was rescued by the introduction of the HearNPV F gene. It was also demonstrated by chemical cross-linking that HearNPV F is present in BVs as an oligomer whereby, unlike GP64, disulfide bonds are not involved. Deglycosylation assays indicated that both F1 and F2 possess N-linked glycans. However, when F was made in Hz2E5 cells, these glycans did not have an α-1-3 core fucose modification that usually occurs in insect cells. As α-1-3 core fucose is a major inducer of an allergic response in humans, the present observation makes the HearNPV–Hz2E5 system an attractive alternative for the production of recombinant glycoproteins for therapeutic use in humans.

scholarly journals Ac23, an Envelope Fusion Protein Homolog in the Baculovirus Autographa californica Multicapsid Nucleopolyhedrovirus, Is a Viral Pathogenicity Factor

2003 ◽  
Vol 77 (1) ◽  
pp. 328-339 ◽  
Author(s):  
Oliver Y. Lung ◽  
Marilyn Cruz-Alvarez ◽  
Gary W. Blissard
Keyword(s):  
Fusion Protein ◽  
Viral Entry ◽  
Fusion Proteins ◽  
Autographa Californica ◽  
Viral Envelope ◽  
Evolutionary Divergence ◽  
Pathogenicity Factor ◽  
Group I ◽  
Group Ii ◽  
Contrast Group

ABSTRACT Viral envelope fusion proteins are important structural proteins that mediate viral entry and may affect or determine the host range of a virus. The acquisition, exchange, and evolution of such envelope proteins may dramatically affect the success and evolutionary divergence of viruses. In the family Baculoviridae, two very different envelope fusion proteins have been identified. Budded virions of group I nucleopolyhedroviruses (NPVs) such as the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), contain the essential GP64 envelope fusion protein. In contrast group II NPVs and granuloviruses have no gp64 gene but instead encode a different envelope protein called F. F proteins from group II NPVs can functionally substitute for GP64 in gp64null AcMNPV viruses, indicating that GP64 and these F proteins serve a similar functional role. Interestingly, AcMNPV (and other gp64-containing group I NPVs) also contain an F gene homolog (Ac23) but the AcMNPV F homolog cannot compensate for the loss of gp64. In the present study, we show that Ac23 is expressed and is found in budded virions. To examine the function of F protein homologs from the gp64-containing baculoviruses, we generated an Ac23null AcMNPV genome by homologous recombination in E. coli. We found that Ac23 was not required for viral replication or pathogenesis in cell culture or infected animals. However, Ac23 accelerated the mortality of infected insect hosts by approximately 28% or 26 h. Thus, Ac23 represents an important viral pathogenicity factor in larvae infected with AcMNPV.

scholarly journals Sequence and organization of the Spodoptera exigua multicapsid nucleopolyhedrovirus genome

1999 ◽  
Vol 80 (12) ◽  
pp. 3289-3304 ◽  
Author(s):  
Wilfred F. J. IJkel ◽  
Elisabeth A. van Strien ◽  
Jacobus G. M. Heldens ◽  
René Broer ◽  
Douwe Zuidema ◽  
...  
Keyword(s):  
Spodoptera Exigua ◽  
Autographa Californica ◽  
Recent Common Ancestor ◽  
Computer Assisted ◽  
Glycoprotein Gene ◽  
Orgyia Pseudotsugata ◽  
Group I ◽  
Group Ii ◽  
Budded Virus ◽  
Assisted Analysis

The nucleotide sequence of the DNA genome of Spodoptera exigua multicapsid nucleopolyhedrovirus (SeMNPV), a group II NPV, was determined and analysed. The genome contains 135611 bp and has a G+C content of 44 mol%. Computer-assisted analysis revealed 139 ORFs of 150 nucleotides or larger; 103 have homologues in Autographa californica MNPV (AcMNPV) and a further 16 have homologues in other baculoviruses. Twenty ORFs are unique to SeMNPV. Major differences in SeMNPV gene content and arrangement were found compared with the group I NPVs AcMNPV, Bombyx mori (Bm) NPV and Orgyia pseudotsugata (Op) MNPV and the group II NPV Lymantria dispar (Ld) MNPV. Eighty-five ORFs were conserved among all five baculoviruses and are considered as candidate core baculovirus genes. Two putative p26 and odv-e66 homologues were identified in SeMNPV, each of which appeared to have been acquired independently and not by gene duplication. The SeMNPV genome lacks homologues of the major budded virus glycoprotein gene gp64, the immediate-early transactivator ie-2 and bro (baculovirus repeat ORF) genes that are found in AcMNPV, BmNPV, OpMNPV and LdMNPV. Gene parity analysis of baculovirus genomes suggests that SeMNPV and LdMNPV have a recent common ancestor and that they are more distantly related to the group I baculoviruses AcMNPV, BmNPV and OpMNPV. The orientation of the SeMNPV genome is reversed compared with the genomes of AcMNPV, BmNPV, OpMNPV and LdMNPV. However, the gene order in the ‘central’ part of baculovirus genomes is highly conserved and appears to be a key feature in the alignment of baculovirus genomes.

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 Functional Analysis of the Putative Fusion Domain of the Baculovirus Envelope Fusion Protein F

2004 ◽  
Vol 78 (13) ◽  
pp. 6946-6954 ◽  
Author(s):  
Marcel Westenberg ◽  
Frank Veenman ◽  
Els C. Roode ◽  
Rob W. Goldbach ◽  
Just M. Vlak ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Conformational Changes ◽  
Cellular Membrane ◽  
Fusion Peptide ◽  
Single Amino Acid ◽  
Viral Infectivity ◽  
Viral Fusion ◽  
F Protein ◽  
Group I ◽  
N Terminus

ABSTRACT Group II nucleopolyhedroviruses (NPVs), e.g., Spodoptera exigua MNPV, lack a GP64-like protein that is present in group I NPVs but have an unrelated envelope fusion protein named F. In contrast to GP64, the F protein has to be activated by a posttranslational cleavage mechanism to become fusogenic. In several vertebrate viral fusion proteins, the cleavage activation generates a new N terminus which forms the so-called fusion peptide. This fusion peptide inserts in the cellular membrane, thereby facilitating apposition of the viral and cellular membrane upon sequential conformational changes of the fusion protein. A similar peptide has been identified in NPV F proteins at the N terminus of the large membrane-anchored subunit F1. The role of individual amino acids in this putative fusion peptide on viral infectivity and propagation was studied by mutagenesis. Mutant F proteins with single amino acid changes as well as an F protein with a deleted putative fusion peptide were introduced in gp64-null Autographa californica MNPV budded viruses (BVs). None of the mutations analyzed had an major effect on the processing and incorporation of F proteins in the envelope of BVs. Only two mutants, one with a substitution for a hydrophobic residue (F152R) and one with a deleted putative fusion peptide, were completely unable to rescue the gp64-null mutant. Several nonconservative substitutions for other hydrophobic residues and the conserved lysine residue had only an effect on viral infectivity. In contrast to what was expected from vertebrate virus fusion peptides, alanine substitutions for glycines did not show any effect.

scholarly journals The F protein of Helicoverpa armigera single nucleopolyhedrovirus can be substituted functionally with its homologue from Spodoptera exigua multiple nucleopolyhedrovirus

2008 ◽  
Vol 89 (3) ◽  
pp. 791-798 ◽  
Author(s):  
Manli Wang ◽  
Ying Tan ◽  
Feifei Yin ◽  
Fei Deng ◽  
Just M. Vlak ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Spodoptera Exigua ◽  
Late Phase ◽  
Positive Control ◽  
Host Proteins ◽  
F Protein ◽  
Helicoverpa Armígera ◽  
Group Ii ◽  
Budded Virus ◽  
Species Specific

F proteins of group II nucleopolyhedroviruses (NPVs) are envelope fusion proteins essential for virus entry and egress. An F-null Helicoverpa armigera single nucleocapsid NPV (HearNPV) bacmid, HaBacΔF, was constructed. This bacmid could not produce infectious budded virus (BV) when transfected into HzAM1 cells, showing that F protein is essential for cell-to-cell transmission of BVs. When HaBacΔF was pseudotyped with the homologous F protein (HaBacΔF-HaF, positive control) or with the heterologous F protein from Spodoptera exigua multinucleocapsid NPV (SeMNPV) (HaBacΔF-SeF), infectious BVs were produced with similar kinetics. In the late phase of infection, the BV titre of HaBacΔF-SeF virus was about ten times lower than that of HaBacΔF-HaF virus. Both pseudotyped viruses were able to fuse HzAM1 cells in a similar fashion. The F proteins of both HearNPV and SeMNPV were completely cleaved into F1 and F2 in the BVs of vHaBacΔF-HaF and vHaBacΔF-SeF, respectively, but the cleavage of SeF in vHaBacΔF-SeF-infected HzAM1 cells was incomplete, explaining the lower BV titre of vHaBacΔF-SeF. Polyclonal antisera against HaF1 and SeF1 specifically neutralized the infection of vHaBacΔF-HaF and vHaBacΔF-SeF, respectively. HaF1 antiserum showed some cross-neutralization with vHaBacΔF-SeF. These results demonstrate that group II NPV F proteins can be functionally replaced with a homologue of other group II NPVs, suggesting that the interaction of F with other viral or host proteins is not absolutely species-specific.

scholarly journals CLINICAL EFFICACY OF RECOMBINANT FACTOR VIII FC FUSION PROTEIN IN HAEMOPHILIA A PATIENT RECEIVING ON DEMAND TREATMENT ONLY

2021 ◽  
Vol 71 (1) ◽  
pp. 62-66
Author(s):  
Saima Zahir ◽  
Tahira Zafar ◽  
Altaf Hussain ◽  
Hamid Saeed Malik ◽  
Pervez Ahmed ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Factor Viii ◽  
Armed Forces ◽  
Recombinant Factor Viii ◽  
Haemophilia A ◽  
On Demand ◽  
Group I ◽  
Fc Fusion Protein ◽  
Male Patients ◽  
Group Ii

Objective: To evaluate the efficacy of recombinant factor VIII FC fusion protein in haemophilia A patientreceiving on demand treatment only. Study Design: Comparative cross sectional study. Place and Duration of Study: Department of Hematology, Armed Forces Institute of Pathology and PakistanHemophilia Welfare Society, Rawalpindi, from Jun to Dec 2017. Methodology: Eighty-nine male patients of Hemophilia A already receiving recombinant factor VIII (20-30 Units/kg) on demand, with no history of inhibitors were included in study. Patients were divided as per age into paediatric and adult group and also on the basis of their basal factor VIII levels into severe, moderate and mild groups. Same patients were switched to recombinant factor VIII FC fusion protein (20-30 Units/kg) and its efficacy was measured and compared with recombinant Factor VIII in terms of dose requirement, injections, bleeds in six month period, presence of inhibitors and side effects. Results: Eighty nine male patients were studied. There was significant reduction in dose from median value of5750 units for group I to 4000 units for group II. Number of bleed in six month period were reduced from 5.3 ingroup I to 4.5 in group II. Number of injections were reduced on average to 1-2 injection per bleed in group II. No inhibitors were detected in group II. Conclusion: rFVIII Fc fusion protein has prolong activity and results in reduction of total dose, number of bleed,dose per bleed and has reduced antigenecity.

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