Functional Analysis of a Conserved Region of the Baculovirus Envelope Fusion Protein, LD130

Pearson, Margot; Russell, Rebecca L. Q.; Rohrmann, George F.

doi:10.1006/viro.2002.1654

Cited by 22 publications

(21 citation statements)

References 24 publications

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“…The L 151 and M 166 residues are the first and the last hydrophobic amino acids of the putative fusion peptide, and this suggests that the F protein can properly function with a smaller hydrophobic face. However, this does not imply that the borders of the putative fusion peptide of SeMNPV F are well defined, because the two conserved aspartic acid residues D 167 and D 170 also appeared to be important for the fusogenic activity of the LdMNPV F protein (33).…”

Section: Discussionmentioning

confidence: 94%

“…2A). The role in the fusion process of the three conserved charged amino acids in the putative fusion peptide, immediately downstream of the proprotein convertase cleavage site, of the Lymantria dispar MNPV (LdMNPV) F protein has already been studied by site-directed mutagenesis (33). In this study, site-directed mutagenesis was used to investigate the role in viral propagation and infectivity of the conserved glycines and lysine as well as the hydrophobic amino acids in the putative fusion peptide of the SeMNPV F protein.…”

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confidence: 99%

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

Westenberg

Veenman

Roode

et al. 2004

J Virol

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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 F 1 . 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.

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Section: Discussionmentioning

confidence: 94%

mentioning

confidence: 99%

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

Westenberg

Veenman

Roode

et al. 2004

J Virol

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“…BVs enter the insect cells through adsorptive endocytosis dependent on endosomal low-pH activation (Volkman & Goldsmith, 1985). The main envelope protein, GP64 of group I (Hefferon et al, 1999) or F protein of group II (IJkel et al, 2000;Pearson et al, 2002), is responsible for BVs entry (Volkman & Goldsmith, 1985). In contrast to BV, ODV is more specialized.…”

Section: Discussionmentioning

confidence: 99%

Functional studies of per os infectivity factors of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus

Song

Wang

Deng

et al. 2008

Journal of General Virology

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A combined functional investigation on the four per os infectivity factors (PIFs) of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearNPV) was conducted in this study. HearNPV bacmids with deletions of p74 (Ha20), pif1 (Ha111), pif2 (Ha132) and pif3 (Ha98) were constructed individually by homologous recombination in Escherichia coli cells. Repaired bacmids with respective pifs were also constructed. Western blot analyses revealed that all four PIFs were structural components of the envelope of HearNPV occlusion-derived virus (ODV). Electron microscopy showed that deletion of the pifs did not have any obvious effects on the morphology of the occlusion bodies (OBs). Bioassay analyses indicated that deletion of any of the above pifs resulted in loss of oral infectivity of OBs. The mixtures of the four pif-deletion mutants also resulted in deficiency of oral infectivity, implying that the four PIFs must be structural components of the same ODV to accomplish their function. Repairing of the respective genes into the pif-deletion bacmids could rescue the oral infectivity of the pif-deletion viruses. Calcofluor, which can damage the peritrophic membrane (PM), could not rescue the defects of the oral infectivity of the pif-deletion viruses, indicating that the PM is not likely to be the functional target of the PIFs.

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“…Mutational analyses of these two F proteins suggest that both the furin cleavage site and a fusion peptide are necessary for membrane fusion activity (40,42,48,49). However, F proteins from group I NPVs, AcMNPV and OpMNPV (viruses with both GP64 and F), do not contain a predicted furin cleavage site, and low pH-triggered membrane fusion activity was not observed when these F proteins were examined in standard syncytium formation assays (reference 41 and unpublished observations).…”

mentioning

confidence: 97%

“…F proteins from the group II NPVs, LdMNPV and SeMNPV, are processed by cleavage at a consensus furin cleavage site (22,42,49). Mutational analyses of these two F proteins suggest that both the furin cleavage site and a fusion peptide are necessary for membrane fusion activity (40,42,48,49).…”

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confidence: 99%

A Cellular Drosophila melanogaster Protein with Similarity to Baculovirus F Envelope Fusion Proteins

Lung

Blissard

2005

J Virol

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Baculovirus F (fusion) proteins are found in the envelopes of budded virions. Recently a Drosophila melanogaster gene (CG4715) that encodes a protein with sequence similarity to baculovirus F proteins was discovered. To examine similarities and differences with baculovirus F proteins, we cloned the D. melanogaster cellular F (Dm-cF) protein gene and analyzed Dm-cF expression and localization. The predicted Dm-cF protein sequence lacks a furin cleavage site, and transiently expressed Dm-cF showed no protein cleavage and no detectable membrane fusion activity. In cell localization studies, transiently expressed Dm-cF was localized to intracellular organelles in D. melanogaster S2 cells, unlike baculovirus F proteins, which localize to cellular plasma membranes. Using reverse transcriptase PCR and Western blot analysis to examine Dm-cF expression in animals, we detected Dm-cF expression in both larval and adult D. melanogaster cells. However, Dm-cF expression was detected only in third instar larvae and adults, suggesting that Dm-cF expression may be developmentally regulated. We also identified genes related to Dm-cF in the genomes of two other Drosophila species, Drosophila yakuba and Drosophila pseudoobscura, and the mosquito Anopheles gambiae. These observations suggest that f genes may be present in the genomes of many insects. Conservation within and between 22 baculovirus and 4 insect F proteins was examined in detail. These studies demonstrate that Dm-cF is expressed in D. melanogaster and suggest that if baculovirus f genes are derived from a host cellular f gene, the function appears to have changed substantially upon adaptation to the baculovirus infection cycle.

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Functional Analysis of a Conserved Region of the Baculovirus Envelope Fusion Protein, LD130

Cited by 22 publications

References 24 publications

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

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

Functional studies of per os infectivity factors of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus

A Cellular Drosophila melanogaster Protein with Similarity to Baculovirus F Envelope Fusion Proteins

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