Antibodies against analogous heptad repeat peptide HR212 of Newcastle Disease Virus inhibit virus-cell membrane fusion

2007 ◽  
Vol 17 (2) ◽  
pp. 150-155 ◽  
Author(s):  
Li Ying ◽  
Tien Po
Keyword(s):  
Cell Membrane ◽  
Newcastle Disease Virus ◽  
Membrane Fusion ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Heptad Repeat

Electron Microscopic Study of Penetration of Newcastle Disease Virus into Cells Leading to Formation of Polykaryocytes

1967 ◽  
Vol 2 (1) ◽  
pp. 71-76
Author(s):  
N. MEISELMAN ◽  
A. KOHN ◽  
D. DANON
Keyword(s):  
Epithelial Cells ◽  
Cell Membrane ◽  
Newcastle Disease Virus ◽  
Microscopic Study ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Cell Membranes ◽  
Viral Envelope ◽  
Electron Microscopic ◽  
Input Multiplicity

Treatment of FL or Lu 106 epithelial cells with Newcastle disease virus (NDV) at an input multiplicity of 500 EID50 per cell induces in these cells the formation of polykaryocytes at the end of 2-3 h of contact. Electron micrographs of such NDV-treated monolayers after 2-10 min of incubation show the presence of virions adsorbed to the cell membranes, in vacuoles and with the viral envelope partly fused with the cell membrane. In polykaryocytes induced by NDV, remnants of cell membranes showing numerous breaks may still be present after 3 h.

scholarly journals Six-helix bundle assembly and characterization of heptad repeat regions from the F protein of Newcastle disease virus

2002 ◽  
Vol 83 (3) ◽  
pp. 623-629 ◽  
Author(s):  
Ming Yu ◽  
Enxiu Wang ◽  
Youfang Liu ◽  
Dianjun Cao ◽  
Ningyi Jin ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Large Scale ◽  
Heptad Repeat ◽  
Scale Production ◽  
F Protein ◽  
Helix Bundle ◽  
Fusion Inhibitors

Paramyxoviruses may adopt a similar fusion mechanism to other enveloped viruses, in which an anti-parallel six-helix bundle structure is formed post-fusion in the heptad repeat (HR) regions of the envelope fusion protein. In order to understand the fusion mechanism and identify fusion inhibitors of Newcastle disease virus (NDV), a member of the Paramyxoviridae family, we have developed an E. coli system that separately expresses the F protein HR1 and HR2 regions as GST fusion proteins. The purified cleaved HR1 and HR2 have subsequently been assembled into a stable six-helix bundle heterotrimer complex. Furthermore, both the GST fusion protein and the cleaved HR2 show virus–cell fusion inhibition activity (IC50 of 1·07–2·93 μM). The solubility of the GST–HR2 fusion protein is much higher than that of the corresponding peptide. Hence this provides a plausible method for large-scale production of HR peptides as virus fusion inhibitors.

scholarly journals Mutations in the Ectodomain of Newcastle Disease Virus Fusion Protein Confer a Hemagglutinin-Neuraminidase-Independent Phenotype

2009 ◽  
Vol 84 (2) ◽  
pp. 1066-1075 ◽  
Author(s):  
Juan Ayllón ◽  
Enrique Villar ◽  
Isabel Muñoz-Barroso
Keyword(s):  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Host Cells ◽  
Heptad Repeat ◽  
Wild Type ◽  
Dye Transfer ◽  
F Protein ◽  
C Terminus ◽  
The Stability

ABSTRACT The entry of enveloped viruses into host cells is preceded by membrane fusion, which in paramyxoviruses is triggered by the fusion (F) protein. Refolding of the F protein from a metastable conformation to a highly stable postfusion form is critical for the promotion of fusion, although the mechanism is still not well understood. Here we examined the effects of mutations of individual residues of the F protein of Newcastle disease virus, located at critical regions of the protein, such as the C terminus of the N-terminal heptad repeat (HRA) and the N terminus of the C-terminal heptad repeat (HRB). Seven of the mutants were expressed at the cell surface, showing differences in antibody reactivity in comparison with the F wild type. The N211A, L461A, I463A, and I463F mutants showed a hyperfusogenic phenotype both in syncytium and in dye transfer assays. The four mutants promoted fusion more efficiently at lower temperatures than the wild type did, meaning they probably had lower energy requirements for activation. Moreover, the N211A, I463A, and I463F mutants exhibited hemagglutinin-neuraminidase (HN)-independent activity when influenza virus hemagglutinin (HA) was coexpressed as an attachment protein. The data are discussed in terms of alterations of the refolding pathway and/or the stability of the prefusion and fusion conformations.

scholarly journals Overexpression of Thiol/Disulfide Isomerases Enhances Membrane Fusion Directed by the Newcastle Disease Virus Fusion Protein

2008 ◽  
Vol 82 (24) ◽  
pp. 12039-12048 ◽  
Author(s):  
Surbhi Jain ◽  
Lori W. McGinnes ◽  
Trudy G. Morrison
Keyword(s):  
Newcastle Disease Virus ◽  
Membrane Fusion ◽  
Disease Virus ◽  
Cell Fusion ◽  
Newcastle Disease ◽  
Syncytium Formation ◽  
F Protein ◽  
Disulfide Exchange ◽  
Disulfide Isomerases ◽  
Cell Cell

ABSTRACT Newcastle disease virus (NDV) fusion (F) protein directs membrane fusion, which is required for virus entry and cell-cell fusion. We have previously shown that free thiols are present in cell surface-expressed NDV F protein and that blocking the production of free thiols by thiol-disulfide exchange inhibitors inhibited the membrane fusion mediated by F protein (J Virol. 81:2328-2339, 2007). Extending these observations, we evaluated the role of the overexpression of two disulfide bond isomerases, protein disulfide isomerase (PDI) and ERdj5, in cell-cell fusion mediated by NDV glycoproteins. The overexpression of these isomerases resulted in significantly increased membrane fusion, as measured by syncytium formation and content mixing. The overexpression of these isomerases enhanced the production of free thiols in F protein when expressed without hemagglutination-neuraminidase (HN) protein but decreased free thiols in F protein expressed with HN protein. By evaluating the binding of conformation-sensitive antibodies, we found that the overexpression of these isomerases favored a postfusion conformation of surface-expressed F protein in the presence of HN protein. These results suggest that isomerases belonging to the PDI family catalyze the production of free thiols in F protein, and free thiols in F protein facilitate membrane fusion mediated by F protein.

scholarly journals Mutational Analysis of Heptad Repeats in the Membrane-Proximal Region of Newcastle Disease Virus HN Protein

1999 ◽  
Vol 73 (5) ◽  
pp. 3630-3637 ◽  
Author(s):  
Judith Stone-Hulslander ◽  
Trudy G. Morrison
Keyword(s):  
Amino Acids ◽  
Newcastle Disease Virus ◽  
Disease Virus ◽  
Newcastle Disease ◽  
Specific Interaction ◽  
Heptad Repeat ◽  
Sequence Motif ◽  
F Protein ◽  
Promotion Activity ◽  
Heptad Repeats

ABSTRACT For most paramyxoviruses, syncytium formation requires the expression of both surface glycoproteins (HN and F) in the same cell, and evidence suggests that fusion involves a specific interaction between the HN and F proteins (X. Hu et al., J. Virol. 66:1528–1534, 1992). The stalk region of the Newcastle disease virus (NDV) HN protein has been implicated in both fusion promotion and virus specificity of that activity. The NDV F protein contains two heptad repeat motifs which have been shown by site-directed mutagenesis to be critical for fusion (R. Buckland et al., J. Gen. Virol. 73:1703–1707, 1992; T. Sergel-Germano et al., J. Virol. 68:7654–7658, 1994; J. Reitter et al., J. Virol. 69:5995–6004, 1995). Heptad repeat motifs mediate protein-protein interactions by enabling the formation of coiled coils. Upon analysis of the stalk region of the NDV HN protein, we identified two heptad repeats. Secondary structure analysis of these repeats suggested the potential for these regions to form alpha helices. To investigate the importance of this sequence motif for fusion promotion, we mutated the hydrophobic a-position amino acids of each heptad repeat to alanine or methionine. In addition, hydrophobic amino acids in other positions were also changed to alanine. Every mutant protein retained levels of attachment activity that was greater than or equal to the wild-type protein activity and bound to conformation-specific monoclonal as well as polyclonal antisera. Neuraminidase activity was variably affected. Every mutation, however, showed a dramatic decrease in fusion promotion activity. The phenotypes of these mutant proteins indicate that individual amino acids within the heptad repeat region of the stalk domain of the HN protein are important for the fusion promotion activity of the protein. These data are consistent with the idea that the HN protein associates with the F protein via specific interactions between the heptad repeat regions of both proteins.

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