Detection of potato mop-top virus capsid readthrough protein in virus particles.

The Potato mop-top virus (PMTV) genome encodes replicase, movement, and capsid proteins on three different RNA species that are encapsidated within tubular rod-shaped particles. Previously, we showed that the protein produced on translational readthrough (RT) of the coat protein (CP) gene, CP-RT, is associated with one extremity of the virus particles, and that the two RNAs encoding replicase and movement proteins can move long distance in the absence of the third RNA (RNA-CP) that encodes the capsid proteins, CP and CP-RT. Here, we examined the roles of the CP and CP-RT proteins on RNA movement using infectious clones carrying mutations in the CP and CP-RT coding domains. The results showed that, in infections established with mutant RNA-CP expressing CP together with truncated CP-RT, systemic movement of the mutant RNA-CP was inhibited but not the movement of the other two RNAs. Furthermore, RNA-CP long-distance movement was inhibited in a mutant clone expressing only CP in the absence of the CP-RT polypeptide. CP-RT was not necessary for particle assembly because virions were observed in leaf extracts infected with the CP-RT deletion mutants. RNA-CP moved long distance when protein expression was suppressed completely or when CP expression was suppressed so that only CP-RT or truncated CP-RT was expressed. CP-RT but not CP interacted with the movement protein TGB1 in the yeast two-hybrid system. CP-RT and TGB1 were detected by enzyme-linked immunosorbent assay in virus particles and the long-distance movement of RNA-CP was correlated with expression of CP-RT that interacted with TGB1; mutant RNA-CP expressing truncated CP-RT proteins that did not interact with TGB1 formed virions but did not move to upper noninoculated leaves. The results indicate that PMTV RNA-CP can move long distance in two distinct forms: either as a viral ribonucleoprotein complex or as particles that are most likely associated with CP-RT and TGB1.

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Nucleolin Interacts with the Dengue Virus Capsid Protein and Plays a Role in Formation of Infectious Virus Particles

Journal of Virology ◽

10.1128/jvi.00704-13 ◽

2013 ◽

Vol 87 (24) ◽

pp. 13094-13106 ◽

Cited By ~ 47

Author(s):

C. A. Balinsky ◽

H. Schmeisser ◽

S. Ganesan ◽

K. Singh ◽

T. C. Pierson ◽

...

Keyword(s):

Dengue Virus ◽

Capsid Protein ◽

Infectious Virus ◽

Virus Capsid ◽

Virus Particles ◽

Virus Capsid Protein

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Detection by immunogold labelling of P75 readthrough protein near an extremity of beet necrotic yellow vein virus particles

Archives of Virology ◽

10.1007/bf01379118 ◽

1994 ◽

Vol 134 (1-2) ◽

pp. 195-203 ◽

Cited By ~ 32

Author(s):

Anne-Marie Haeberl� ◽

Christiane Stussi-Garaud ◽

Corinne Schmitt ◽

J. -C. Garaud ◽

K. E. Richards ◽

...

Keyword(s):

Immunogold Labelling ◽

Yellow Vein ◽

Virus Particles ◽

Readthrough Protein

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Analysis of SAT1 type foot-and-mouth disease virus capsid proteins: Influence of receptor usage on the properties of virus particles

Virus Research ◽

10.1016/j.virusres.2010.12.002 ◽

2011 ◽

Vol 155 (2) ◽

pp. 462-472 ◽

Cited By ~ 16

Author(s):

Francois F. Maree ◽

Belinda Blignaut ◽

Lisa Aschenbrenner ◽

Tom Burrage ◽

Elizabeth Rieder

Keyword(s):

Disease Virus ◽

Foot And Mouth Disease ◽

Mouth Disease ◽

Capsid Proteins ◽

Virus Capsid ◽

Virus Particles ◽

Receptor Usage ◽

Mouth Disease Virus ◽

Foot And Mouth

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Complete sequence of RNA 1 and the presence of tRNA-like structures in all RNAs of Potato mop-top virus, genus Pomovirus

Journal of General Virology ◽

10.1099/0022-1317-80-10-2779 ◽

1999 ◽

Vol 80 (10) ◽

pp. 2779-2784 ◽

Cited By ~ 38

Author(s):

Eugene I. Savenkov ◽

Maria Sandgren ◽

Jari P. T. Valkonen

Keyword(s):

Broad Bean ◽

Stop Codon ◽

Phylogenetic Analyses ◽

Complete Sequence ◽

Open Reading Frame ◽

Untranslated Regions ◽

Necrosis Virus ◽

Reading Frame ◽

Potato Mop Top Virus ◽

Readthrough Protein

The complete nucleotide sequence (6043 nt) of RNA 1 from Potato mop-top virus (PMTV-Sw), the type member of the genus Pomovirus, was determined. The first (5′-terminal) open reading frame (ORF 1) encodes a predicted protein of 148 kDa. ORF 2 extends through the opal stop codon of ORF 1 producing a predicted readthrough protein of 206 kDa which resembles the RNA-dependent RNA polymerases (RdRp) of other fungal-transmitted viruses. It includes a methyltransferase, a helicase and a GDD RdRp motif, respectively. Phylogenetic analyses of RdRps indicated that PMTV is most closely related to Beet soil-borne virus (genusPomovirus), Broad bean necrosis virus (genus Pomovirus) and Soil-borne wheat mosaic virus (genus Furovirus), and is more distantly related to the other viruses of the former furovirus group. The 5′ and 3′ termini of RNA 1 in PMTV contained untranslated regions (UTR) of 114 nt and 489 nt, respectively. The 3′-UTR of RNA 1 contained a tRNA-like structure, which has previously been reported in the 3′-UTR of RNA 2 but not RNA 3. However, in this study, the tRNA-like structure was also found in the 3′-UTR of RNA 3, which confirms its presence in the 3′-UTRs of all three RNAs of PMTV.

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Potato mop-top virus RNA Can Move Long Distance in the Absence of Coat Protein: Evidence from Resistant, Transgenic Plants

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2000.13.1.125 ◽

2000 ◽

Vol 13 (1) ◽

pp. 125-128 ◽

Cited By ~ 26

Author(s):

Kara D. McGeachy ◽

Hugh Barker

Keyword(s):

Coat Protein ◽

Transgenic Plants ◽

Triple Gene Block ◽

Leaf Extracts ◽

Long Distance ◽

Transgenic Expression ◽

Gene Block ◽

Virus Particles ◽

Virus Rna ◽

Potato Mop Top Virus

Transgenic expression of a translatable version of the Potato mop-top virus (PMTV) coat protein (CP) gene (encoded by RNA 3) in Nicotiana benthamiana prevented production of symptoms and infective virus particles. RNAs 1 and 2 accumulated in inoculated and systemic leaves but, apart from small amounts of CP transgene RNA transcript, no genomic-length RNA 3 was found. Crude leaf extracts from inoculated plants were not infective. However, when RNA extracts from such transgenic plants were inoculated to nontransgenic N. benthamiana and N. clevelandii, RNA 1 and RNA 2 replicated in systemic leaves of both species in the absence of RNA 3 and virus particles, but symptoms did not develop. We suggest that the triple-gene block proteins of PMTV (encoded by RNA 2) represent a class of long-distance RNA movement factors.

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Reduced redox potential of the cytosol is important for African swine fever virus capsid assembly and maturation

Journal of General Virology ◽

10.1099/vir.0.82257-0 ◽

2007 ◽

Vol 88 (1) ◽

pp. 77-85 ◽

Cited By ~ 7

Author(s):

Christian Cobbold ◽

Miriam Windsor ◽

James Parsley ◽

Ben Baldwin ◽

Thomas Wileman

Keyword(s):

African Swine Fever Virus ◽

African Swine Fever ◽

Fever Virus ◽

Oxidized Glutathione ◽

Virus Capsid ◽

Virus Particles ◽

Cytoplasmic Face ◽

Reducing Environment ◽

High Concentrations

Assembly of African swine fever virus (ASFV) involves the transfer of the major capsid protein, p73, from the cytosol onto the cytoplasmic face of endoplasmic reticulum-derived membranes. During this process, the folding of p73 is dependent upon transient association with a specific viral chaperone, CAP80. The cell cytoplasm maintains high concentrations of reduced glutathione, leading to a reducing environment. Here, the effects of redox environment on the assembly of ASFV have been studied. Diamide, which oxidizes the cell cytosol, slowed the folding of p73 and prevented release from CAP80 and subsequent binding of p73 to membranes. Similarly, cell oxidation slowed the assembly of p73 molecules already bound to membranes into virus capsid precursors. Interestingly, addition of oxidized glutathione to newly assembled virus capsid precursors in vitro led to disassembly; however, virus particles released from cells were resistant to oxidized glutathione. These data show that assembly of ASFV requires the reducing environment that prevails in the cytosol, but as the virus matures, it becomes resistant to oxidation, possibly indicating preparation for release from the cell.

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Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070199 ◽

1978 ◽

Vol 36 (3) ◽

pp. 470-482 ◽

Cited By ~ 1

Author(s):

R.W. Horne

Keyword(s):

Electron Microscopy ◽

Image Processing ◽

Analytical Techniques ◽

Staining Technique ◽

High Resolution Electron Microscopy ◽

Optical Diffraction ◽

Full Potential ◽

Virus Particles ◽

Resolution Electron ◽

Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

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Biological and Surface Properties of C-Type Virus Particles Produced by Novikoff Ascites Hepatoma Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079395 ◽

1977 ◽

Vol 35 ◽

pp. 388-389

Author(s):

D.C. Hixson ◽

J.C. Chan ◽

J.M. Bowen ◽

E.F. Walborg

Keyword(s):

Surface Properties ◽

Ricinus Communis ◽

Rat Kidney ◽

Leukemia Virus ◽

Viral Envelope ◽

Virus Particles ◽

Chemically Induced ◽

Sarcoma Virus ◽

Hepatocarcinoma Cells ◽

Type C

Several years ago Karasaki (1) reported the production of type C virus particles by Novikoff ascites hepatocarcinoma cells. More recently, Weinstein (2) has reported the presence of type C virus particles in cell cultures derived from transplantable and primary hepatocellular carcinomas. To date, the biological function of these virus and their significance in chemically induced hepatocarcinogenesis are unknown. The present studies were initiated to determine a possible role for type C virus particles in chemically induced hepatocarcinogenesis. This communication describes results of studies on the biological and surface properties of type C virus associated with Novikoff hepatocarcinoma cells.Ecotropic and xenotropic murine leukemia virus (MuLV) activity in ascitic fluid of Novikoff tumor-bearing rats was assayed in murine sarcoma virus transformed S+L- mouse cells and S+L- mink cells, respectively. The presence of sarcoma virus activity was assayed in non-virus-producing normal rat kidney (NRK) cells. Ferritin conjugates of concanavalin A (Fer-Con wheat germ agglutinin (Fer-WGA), and Ricinus communis agglutinins I and II (Fer-RCAI and Fer-RCAII) were used to probe the structure and topography of saccharide determinants present on the viral envelope.

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Further Observations on the Virus of Epizootic Diarrhea of Infant Mice. An Electron Microscopic Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100060568 ◽

1967 ◽

Vol 25 ◽

pp. 110-111

Author(s):

W. G. Banfield ◽

G. Kasnic ◽

J. H. Blackwell

Keyword(s):

Electron Microscope ◽

Infected Cell ◽

Microscopic Study ◽

Intestinal Epithelium ◽

Ultrastructural Study ◽

Osmium Tetroxide ◽

Lead Citrate ◽

Electron Microscopic ◽

Virus Particles ◽

Infected Cells

An ultrastructural study of the intestinal epithelium of mice infected with the agent of epizootic diarrhea of infant mice (EDIM virus) was first performed by Adams and Kraft. We have extended their observations and have found developmental forms of the virus and associated structures not reported by them.Three-day-old NLM strain mice were infected with EDIM virus and killed 48 to 168 hours later. Specimens of bowel were fixed in glutaraldehyde, post fixed in osmium tetroxide and embedded in epon. Sections were stained with uranyl magnesium acetate followed by lead citrate and examined in an updated RCA EMU-3F electron microscope.The cells containing virus particles (infected) are at the tips of the villi and occur throughout the intestine from duodenum through colon. All developmental forms of the virus are present from 48 to 168 hours after infection. Figure 1 is of cells without virus particles and figure 2 is of an infected cell. The nucleus and cytoplasm of the infected cells appear clearer than the cells without virus particles.

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