The hemagglutinin of recent measles virus isolates induces cell fusion in a marmoset cell line, but not in other CD46-positive human and monkey cell lines, when expressed together with the F protein

1998 ◽  
Vol 143 (2) ◽  
pp. 213-225 ◽  
Author(s):  
K. Tanaka ◽  
M. Xie ◽  
Y. Yanagi
Keyword(s):  
Cell Line ◽  
Cell Fusion ◽  
Cell Lines ◽  
Measles Virus ◽  
F Protein ◽  
Monkey Cell ◽  
Virus Isolates

Quantitative cell fusion: the fusion sensitivity (FS) potential

1981 ◽  
Vol 49 (1) ◽  
pp. 87-97
Author(s):  
D. Rohme
Keyword(s):  
Cell Line ◽  
Cell Fusion ◽  
Cell Lines ◽  
Dose Response ◽  
Sendai Virus ◽  
Biological Significance ◽  
Diploid Cell ◽  
Mammalian Cell Lines ◽  
Virus Dose ◽  
A Cell

The dose response of Sendai virus-induced cell fusion was studied in 10 mammalian cell lines, comprising 5 continuous and 5 diploid cell lines originating from 5 species. The extent of fusion was calculated using a parameter directly proportional to the number of fusion events (t-parameter). At lower levels of fusion the dose response was found to be based on the same simple kinetic rules in all cell lines and was defined by the formula: t = FS. FAU/(I + FS. FAU), where FS (fusion sensitivity) is a cell-specific constant of the fusion rate and FAU (fusion activity units) is the virus dose. The FS potential of a cell line was determined as the linear regression coefficient of the fusion index (t/(I - t)) on the virus dose. At higher levels of fusion, when the fusion extent reached cell-line-specific maximal levels, the dose response was not as uniform. In general, and particularly in the cases of the diploid cell lines, these maximal levels were directly proportional to the FS potentials. Thus, it was concluded that the FS potential is the basic quantitative feature, which expresses the cellular fusion efficiency. The fact that FS varied extensively between cell lines, but at the same time apparently followed certain patterns (being higher in continuous compared to diploid cell lines and being related to the species of origin of the cells), emphasizes it biological significance as well as its possible usefulness in studies of the efficiency of various molecular interactions in the cell membrane/cytoskeleton system.

scholarly journals Previously Unrecognized Amino Acid Substitutions in the Hemagglutinin and Fusion Proteins of Measles Virus Modulate Cell-Cell Fusion, Hemadsorption, Virus Growth, and Penetration Rate

2009 ◽  
Vol 83 (17) ◽  
pp. 8713-8721 ◽  
Author(s):  
Hiromi Okada ◽  
Masae Itoh ◽  
Kyosuke Nagata ◽  
Kaoru Takeuchi
Keyword(s):  
Amino Acid ◽  
Cell Fusion ◽  
Measles Virus ◽  
Vero Cells ◽  
Amino Acid Substitutions ◽  
Wild Type ◽  
Virus Growth ◽  
F Protein ◽  
H Protein ◽  
Cell Cell

ABSTRACT Wild-type measles virus (MV) isolated in B95a cells could be adapted to Vero cells after several blind passages. In this study, we have determined the complete nucleotide sequences of the genomes of the wild type (T11wild) and its Vero cell-adapted (T11Ve-23) MV strain and identified amino acid substitutions R516G, E271K, D439E and G464W (D439E/G464W), N481Y/H495R, and Y187H/L204F in the nucleocapsid, V, fusion (F), hemagglutinin (H), and large proteins, respectively. Expression of mutated H and F proteins from cDNA revealed that the H495R substitution, in addition to N481Y, in the H protein was necessary for the wild-type H protein to use CD46 efficiently as a receptor and that the G464W substitution in the F protein was important for enhanced cell-cell fusion. Recombinant wild-type MV strains harboring the F protein with the mutations D439E/G464W [F(D439E/G464W)] and/or H(N481Y/H495R) protein revealed that both mutated F and H proteins were required for efficient syncytium formation and virus growth in Vero cells. Interestingly, a recombinant wild-type MV strain harboring the H(N481Y/H495R) protein penetrated slowly into Vero cells, while a recombinant wild-type MV strain harboring both the F(D439E/G464W) and H(N481Y/H495R) proteins penetrated efficiently into Vero cells, indicating that the F(D439E/G464W) protein compensates for the inefficient penetration of a wild-type MV strain harboring the H(N481Y/H495R) protein. Thus, the F and H proteins synergistically function to ensure efficient wild-type MV growth in Vero cells.

scholarly journals Characterisation of the NES2Y cell line and its use in the production of human glucose-responsive insulin producing (hGRIP) cell lines by cell-cell fusion

Islets ◽  
2009 ◽  
Vol 1 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Gary G. Adams ◽  
A Uddin ◽  
M Vives-Pi ◽  
R Pujol-Borrell
Keyword(s):  
Cell Line ◽  
Cell Fusion ◽  
Cell Lines ◽  
Cell Cell

scholarly journals Leucine at position 278 of the AIK-C measles virus vaccine strain fusion protein is responsible for reduced syncytium formation

2001 ◽  
Vol 82 (9) ◽  
pp. 2143-2150 ◽  
Author(s):  
Tetsuo Nakayama ◽  
Katsuhiro Komase ◽  
Rina Uzuka ◽  
Akiyoshi Hoshi ◽  
Takao Okafuji
Keyword(s):  
Cell Fusion ◽  
Vaccine Strain ◽  
Measles Virus ◽  
Direct Sequencing ◽  
Infectious Clone ◽  
Syncytium Formation ◽  
Vero Cells ◽  
F Protein ◽  
Extensive Cell ◽  
Plaque Purification

The live measles virus (MV) vaccine strain AIK-C was attenuated from the wild-type strain Edmonston by plaque purification at 33 °C. Strain AIK-C grew well at 33 °C with a mixture of small-and medium-sized plaques in Vero cells, but did not grow well at 40 °C. To investigate fusion inducibility, expression plasmids for the fusion (F) and haemagglutinin (H) protein regions of MV strains AIK-C (pAIK-F01 and pAIK-H) and Edmonston (pEdm-F and pEdm-H) were constructed. pEdm-F induced extensive cell fusion in B95a and Vero cells under the control of T7 RNA polymerase, whereas a sharp reduction in syncytium formation was observed when pAIK-F01 was used. Six amino acid differences were determined between pAIK-F01 and pEdm-F. Direct sequencing showed that the seed strain AIK-C contained either Leu or Phe at position 278 of the F protein. Experiments using recombinant F protein plasmids demonstrated that those with Leu at position 278 induced poor syncytium formation, while those with Phe at position 278 (Edmonston type) induced extensive cell fusion. Replacement of Phe with Leu at position 278 of pEdm-F reduced fusion-inducing capability. A full-length infectious clone of AIK-C with Leu at position 278 of the F protein was constructed. The rescued virus produced small plaques in Vero cells. However, the same rescued virus with Phe at position 278 produced large plaques. It was concluded that Leu at position 278 of the F protein of the MV vaccine strain AIK-C is responsible for the formation of small plaques.

scholarly journals Measles Virus Glycoprotein Complexes Preassemble Intracellularly and Relax during Transport to the Cell Surface in Preparation for Fusion

2014 ◽  
Vol 89 (2) ◽  
pp. 1230-1241 ◽  
Author(s):  
Melinda A. Brindley ◽  
Sukanya Chaudhury ◽  
Richard K. Plemper
Keyword(s):  
Cell Surface ◽  
Cell Fusion ◽  
Receptor Binding ◽  
Measles Virus ◽  
Envelope Glycoproteins ◽  
Fusion Activity ◽  
Protein Interface ◽  
High Cell ◽  
Attachment Protein ◽  
F Protein

ABSTRACTMeasles virus (MeV), a morbillivirus within the paramyxovirus family, expresses two envelope glycoproteins. The attachment (H) protein mediates receptor binding, followed by triggering of the fusion (F) protein, which leads to merger of the viral envelope with target cell membranes. Receptor binding by members of related paramyxovirus genera rearranges the head domains of the attachment proteins, liberating an F-contact domain within the attachment protein helical stalk. However, morbillivirus glycoproteins first assemble intracellularly prior to receptor binding, raising the question of whether alternative protein-protein interfaces are involved or whether an entirely distinct triggering principle is employed. To test these possibilities, we generated headless H stem mutants of progressively shorter length. Conformationally restricted H stems remained capable of intracellular assembly with a standard F protein and a soluble MeV F mutant. Proteolytic maturation of F, but not the altered biochemical conditions at the cell surface, reduces the strength of glycoprotein interaction, readying the complexes for triggering. F mutants stabilized in the prefusion conformation interact with H intracellularly and at the cell surface, while destabilized F mutants interact only intracellularly, prior to F maturation. These results showcase an MeV entry machinery that functionally varies conserved motifs of the proposed paramyxovirus infection pathway. Intracellular and plasma membrane-resident MeV glycoprotein complexes employ the same protein-protein interface. F maturation prepares for complex separation after triggering, and the H head domains in prereceptor-bound conformation prevent premature stalk rearrangements and F activation. Intracellular preassembly affects MeV fusion profiles and may contribute to the high cell-to-cell fusion activity characteristic of the morbillivirus genus.IMPORTANCEParamyxoviruses of the morbillivirus genus, such as measles, are highly contagious, major human and animal pathogens. MeV envelope glycoproteins preassemble intracellularly into tightly associated hetero-oligomers. To address whether preassembly reflects a unique measles virus entry strategy, we characterized the protein-protein interface of intracellular and surface-exposed fusion complexes and investigated the effect of the attachment protein head domains, glycoprotein maturation, and altered biochemical conditions at the cell surface on measles virus fusion complexes. Our results demonstrate that measles virus functionally varies conserved elements of the paramyxovirus entry pathway, providing a possible explanation for the high cell-to-cell fusion activity of morbilliviruses. Insight gained from these data affects the design of effective broad-spectrum paramyxovirus entry inhibitors.

scholarly journals Measles Virus Fusion Protein Is Palmitoylated on Transmembrane-Intracytoplasmic Cysteine Residues Which Participate in Cell Fusion

1998 ◽  
Vol 72 (10) ◽  
pp. 8198-8204 ◽  
Author(s):  
Monserrat Caballero ◽  
Juan Carabaña ◽  
Javier Ortego ◽  
Rafael Fernández-Muñoz ◽  
María L. Celma
Keyword(s):  
Fusion Protein ◽  
Palmitic Acid ◽  
Cell Fusion ◽  
Measles Virus ◽  
Transmembrane Domain ◽  
Gene Transfection ◽  
F Protein ◽  
F Gene ◽  
Extracellular Virus ◽  
Viral Fusion Protein

ABSTRACT [3H]palmitic acid was metabolically incorporated into the viral fusion protein (F) of Edmonston or freshly isolated measles virus (MV) during infection of human lymphoid or Vero cells. The uncleaved precursor F0 and the F1 subunit from infected cells and extracellular virus were both labeled, indicating that palmitoylation can take place prior to F0 cleavage and that palmitoylated F protein was incorporated into virus particles. [3H]palmitic acid was released from F protein upon hydroxylamine or dithiothreitol treatment, indicating a thioester linkage. In cells transfected with the cloned MV F gene, in which the cysteines located in the intracytoplasmic and transmembrane domains (Cys 506, 518, 519, 520, and 524) were replaced by serine, a major reduction of [3H]palmitic acid incorporation was observed for F mutated at Cys 506 and, to a lesser extent, at Cys 518 and Cys 524. We also observed incorporation of [3H]palmitic acid in the F1 subunit of canine distemper virus F protein. Cell fusion induced by cotransfection of cells with MV F and H (hemagglutinin) genes was significantly reduced after replacement of Cys 506 or Cys 519 with serine in the MV F gene. Transfection with the F gene with a mutation for Cys 518 abolished cell fusion, although less mutant protein was detected on the cell surface. These results suggest that the F protein transmembrane domain cysteines 506 and 518 participate in structures involved in cell fusion, possibly mediated by palmitoylation.

scholarly journals M protein of subacute sclerosing panencephalitis virus, synergistically with the F protein, plays a crucial role in viral neuropathogenicity

2021 ◽  
Vol 102 (10) ◽  
Author(s):  
Yuto Satoh ◽  
Kurara Higuchi ◽  
Daichi Nishikawa ◽  
Hiroshi Wakimoto ◽  
Miho Konami ◽  
...  
Keyword(s):  
Cell Fusion ◽  
Persistent Infection ◽  
High Frequency ◽  
Measles Virus ◽  
Subacute Sclerosing Panencephalitis ◽  
M Protein ◽  
Fusion Activity ◽  
F Protein ◽  
Sspe Virus ◽  
Cell Cell

Subacute sclerosing panencephalitis (SSPE) is a rare fatal neurodegenerative disease caused by a measles virus (MV) variant, SSPE virus, that accumulates mutations during long-term persistent infection of the central nervous system (CNS). Clusters of mutations identified around the matrix (M) protein in many SSPE viruses suppress productive infectious particle release and accelerate cell–cell fusion, which are features of SSPE viruses. It was reported, however, that these defects of M protein function might not be correlated directly with promotion of neurovirulence, although they might enable establishment of persistent infection. Neuropathogenicity is closely related to the character of the viral fusion (F) protein, and amino acid substitution(s) in the F protein of some SSPE viruses confers F protein hyperfusogenicity, facilitating viral propagation in the CNS through cell–cell fusion and leading to neurovirulence. The F protein of an SSPE virus Kobe-1 strain, however, displayed only moderately enhanced fusion activity and required additional mutations in the M protein for neuropathogenicity in mice. We demonstrated here the mechanism for the M protein of the Kobe-1 strain supporting the fusion activity of the F protein and cooperatively inducing neurovirulence, even though each protein, independently, has no effect on virulence. The occurrence of SSPE has been estimated recently as one in several thousand in children who acquired measles under the age of 5 years, markedly higher than reported previously. The probability of a specific mutation (or mutations) occurring in the F protein conferring hyperfusogenicity and neuropathogenicity might not be sufficient to explain the high frequency of SSPE. The induction of neurovirulence by M protein synergistically with moderately fusogenic F protein could account for the high frequency of SSPE.

scholarly journals CD9-dependent regulation of Canine distemper virus-induced cell–cell fusion segregates with the extracellular domain of the haemagglutinin

2006 ◽  
Vol 87 (6) ◽  
pp. 1635-1642 ◽  
Author(s):  
K. Singethan ◽  
E. Topfstedt ◽  
S. Schubert ◽  
W. P. Duprex ◽  
B. K. Rima ◽  
...  
Keyword(s):  
Cell Fusion ◽  
Measles Virus ◽  
Canine Distemper Virus ◽  
Transmembrane Protein ◽  
Extracellular Domain ◽  
Canine Distemper ◽  
Viral Glycoprotein ◽  
F Protein ◽  
H Protein ◽  
Cell Cell

Antibodies to CD9, a member of the tetraspan transmembrane-protein family, selectively inhibit Canine distemper virus (CDV)-induced cell–cell fusion. Neither CDV-induced virus–cell fusion nor cell–cell fusion induced by the closely related morbillivirus Measles virus (MV) is affected by anti-CD9 antibodies. As CDV does not bind CD9, an unknown, indirect mechanism is responsible for the observed inhibition of cell–cell fusion. It was investigated whether this effect was restricted to only one viral glycoprotein, either the haemagglutinin (H) or the fusion (F) protein, which form a fusion complex on the surface of virions and infected cells, or whether it is dependent on both in transient co-transfection assays. The susceptibility to CD9 antibodies segregates with the H protein of CDV. By exchanging portions of the H proteins of CDV and MV, it was determined that the complete extracellular domain, including the predicted stem structure (stem 1, barrel strand 1 and stem 2) and globular head domain, of the CDV-H protein mediates the effect. This suggests that interaction of the CDV-H protein with an unknown cellular receptor(s) is regulated by CD9, rather than F protein-mediated membrane fusion.

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