Classification of Rhabdovirus Proteins: a Proposal

Vesicular stomatitis virus (VSV) particles formed at early times after infection contain only one-third the amount of viral glycoprotein (G protein), relative to the major internal structural proteins M and N, as is found in particles released later. These "early" particles also have a lower density in equilibrium sucrose gradients than do those formed later; however, the sedimentation velocity and specific infectivity of these two classes of particles are the same. VSV-infected cells also release virus-like particles which sediment considerably faster than authentic virions and contain a higher-than-normal proportion of the VSV G protein relative to internal VSV proteins. These particles have a reduced specific infectivity but a normal density in sucrose gradients. All classes of VSV virions contain a constant proportion of M and N polypeptides. The ratio of G protein to M or N protein, in contrast, can vary over a sixfold range; this implies that an interaction between a precise number of surface G proteins with either of the underlying M and N proteins is not a prerequisite for budding of infectious viral particles from the cell surface.A vesicular stomatitis virus (VSV) particle, like those of most lipid-containing animal viruses, is formed by budding from the plasma membrane of an infected cell (reviewed in references 3, 11, 12, 18, and 21). This complex process is not well understood, but must reflect the structural organization of the viral proteins in the infected cell and in the virion. The transmembrane (5,6,13,16,20) viral glycoprotein (G protein) is imbedded in the plasma membrane; it becomes, by far, the major protein exposed on the surfaces of infected cells and on the surface of the virion (2,3,7,21). The M protein is apparently localized in the inner surface of the virus membrane and may serve as a "bridge" between the C; protein and the viral nucleocapsid, which consists of one molecule of viral RNA and the other three virus-encoded proteins, N, NS, and L (11,12,17,21,22).The VSV budding process is not totally spe-

mentioning

confidence: 99%

Heterogeneity of vesicular stomatitis virus particles: implications for virion assembly

Lodish¹,

Porter²

1980

“…bCoding potential of each mRNA species was calculated as one-ninth the corresponding singlestranded (ss) RNA molecular weight. c The molecular weights of VSV proteins are from Wagner et al (25). the 10 points fall very close to a straight line (data not shown).…”

Section: Separation Of 12smentioning

confidence: 82%

Characterization of vesicular stomatitis virus mRNA species synthesized in vitro

Rhodes¹,

Abraham²,

Colonno³

et al. 1977

The smallest size class of mRNA (12S) synthesized in vitro by the virionassociated RNA polymerase of vesicular stomatitis virus contains two mRNA species of similar molecular weight that code for the viral M and NS proteins. The resolution of these mRNA species was achieved by converting them to duplexes by annealing with the genome RNA, followed by RNase T2 treatment and separation in a polyacrylamide gel. Using this separation technique, the mRNA's were identified by comparing the relative resistance of their syntheses to UV irradiation of the virus. The molecular weights of these two mRNA species calculated as duplex RNAs were smaller than expected. The possible reasons for this discrepancy are discussed.

“…Polyacrylamide gel electrophoresis of sodium dodecyl sulfate-dissociated VS virions labeled with [4,5-3H]leucine (5 jiCi/ml) and [f4C]glycerol (0.5 juCi/ml). The designations of viralpolypeptides (L, G, N, NS, M) are according to Wagner et al (37). with dimethylformamide showed no inactivation.…”

Section: Figmentioning

confidence: 99%

Effects of Filipin on the Structure and Biological Activity of Enveloped Viruses

Majuk

Bittman

Landsberger

et al. 1977

The interaction of the polyene antibiotic filipin with membrane-bound cholesterol in vesicular stomatitis (VS), influenza, and Rauscher leukemia virions was studied. Exposure of virions to filipin resulted in a series of depressions and ridges in the envelope of VS virions, with a periodicity of 15 to 20 nm perpendicular to the long axis of the particle; similar morphological alterations were observed in negatively stained preparations, in thin-sectioned virions, and in protease-treated virions that lack surface glycoproteins. This morphological effect was specific for filipin, since the envelopes of VS virions that had been treated with another polyene antibiotic, amphotericin B, exhibited markedly different morphology. Morphological alterations induced by filipin in influenza and Rauscher leukemia virions differed from those seen in VS virions. The infectivity of filipin-treated VS virions was reduced up to 500-fold, whereas influenza virions were resistant to filipin treatment. Incorporation of filipin into the virions was demonstrated, and no release of either lipids or proteins from virions was detected after filipin treatment. A stoichiometry of approximately 1 mol of bound filipin per mol of cholesterol was found in both intact and protease-treated VS virions. The equilibrium dissociation constant for filipin-cholesterol interaction was approximately 74-fold larger in intact than in protease-treated VS virions. The initial rate of association of filipin with cholesterol in intact virions was slower than that in protease-treated particles. The fluidity of lipids in VS viral membranes, as probed by a stearic acid derivative spin label, was markedly reduced when either intact or protease-treated virions were treated with filipin.