scholarly journals Tobacco mosaic virus and the study of early events in virus infections

1999 ◽  
Vol 354 (1383) ◽  
pp. 603-611 ◽  
Author(s):  
John G. Shaw
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Host Cells ◽  
Progeny Virus ◽  
Virus Infections ◽  
Relevant Research ◽  
Protein Subunits ◽  
Virus Particles ◽  
Initial Interaction ◽  
Positive Strand Rna

In order to establish infections, viruses must be delivered to the cells of potential hosts and must then engage in activities that enable their genomes to be expressed and replicated. With most viruses, the events that precede the onset of production of progeny virus particles are referred to as the early events and, in the case of positive–strand RNA viruses, they include the initial interaction with, and the entry of, host cells and the release (uncoating) of the genome from the virus particles. Though the early events remain one of the more poorly understood areas of plant virology, the virus with which most of the relevant research has been performed is tobacco mosaic virus (TMV). In spite of this effort, there remains much uncertainty about the form or constituent of the virus that actually enters the initially invaded cell in a plant and about the mechanism(s) that trigger the subsequent uncoating (virion disassembly) reactions. A variety of approaches have been used in attempts to determine the fate of TMV particles that are involved in the establishment of an infection and these are briefly described in this review. In some recent work, it has been proposed that the uncoating process involves the bidirectional release of coat protein subunits from the viral RNA and that these activities may be mediated by cotranslational and coreplicational disassembly mechanisms.

scholarly journals RELATION OF TOBACCO MOSAIC VIRUS TO THE HOST CELLS

1967 ◽  
Vol 33 (3) ◽  
pp. 665-678 ◽  
Author(s):  
Katherine Esau ◽  
James Cronshaw
Keyword(s):  
Electron Microscope ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Host Cells ◽  
Vascular Bundles ◽  
Mesophyll Cells ◽  
Virus Particles ◽  
Nicotiana Tabacum L ◽  
Parenchyma Cells ◽  
Particle Aggregates

The relation of tobacco mosaic virus (TMV) to host cells was studied in leaves of Nicotiana tabacum L. systemically infected with the virus. The typical TMV inclusions, striate or crystalline material and ameboid or X-bodies, which are discernible with the light microscope, and/or particles of virus, which are identifiable with the electron microscope, were observed in epidermal cells, mesophyll cells, parenchyma cells of the vascular bundles, differentiating and mature tracheary elements, and immature and mature sieve elements. Virus particles were observed in the nuclei and the chloroplasts of parenchyma cells as well as in the ground cytoplasm, the vacuole, and between the plasma membrane and the cell wall. The nature of the conformations of the particle aggregates in the chloroplasts was compatible with the concept that some virus particles may be assembled in these organelles. The virus particles in the nuclei appeared to be complete particles. Under the electron microscope the X-body constitutes a membraneless assemblage of endoplasmic reticulum, ribosomes, virus particles, and of virus-related material in the form of wide filaments indistinctly resolvable as bundles of tubules. Some parenchyma cells contained aggregates of discrete tubules in parallel arrangement. These groups of tubules were relatively free from components of host protoplasts.

Tobacco mosaic virus particles contain ubiquitinated coat protein subunits

Virology ◽  
1988 ◽  
Vol 165 (1) ◽  
pp. 310-312 ◽  
Author(s):  
David D. Dunigan ◽  
Ralf G. Dietzgen ◽  
James E. Schoelz ◽  
Milton Zaitlin
Keyword(s):  
Coat Protein ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Protein Subunits ◽  
Virus Particles

scholarly journals Production of Platinum Atom Nanoclusters at One End of Helical Plant Viruses

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yuri Drygin ◽  
Olga Kondakova ◽  
Joseph Atabekov
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Pt Nanoparticles ◽  
Potato Virus X ◽  
Plant Viruses ◽  
Platinum Atom ◽  
Protein Subunits ◽  
Virus Particles ◽  
Atom Clusters

Platinum atom clusters (Pt nanoparticles, Pt-NPs) were produced selectively at one end of helical plant viruses, tobacco mosaic virus (TMV) and potato virus X (PVX), when platinum coordinate compounds were reduced chemically by borohydrides. Size of the platinum NPs depends on conditions of the electroless deposition of platinum atoms on the virus. Results suggest that the Pt-NPs are bound concurrently to the terminal protein subunits and the 5′ end of encapsidated TMV RNA. Thus, a special structure of tobacco mosaic virus and potato X virus particles with nanoparticles of platinum, which looks like a push-pin with platinum head and virus needle, was obtained. Similar results were obtained with ultrasonically fragmented TMV particles. By contrast, the Pt-NPs fully filled the central axial hole ofin vitroassembled RNA-free TMV-like particles. We believe that the results presented here will be valuable in the fundamental understanding of interaction of viral platforms with ionic metals and in a mechanism of nanoparticles formation.

scholarly journals THE STRUCTURE OF CELLS DURING TOBACCO MOSAIC VIRUS REPRODUCTION

1965 ◽  
Vol 25 (3) ◽  
pp. 77-97 ◽  
Author(s):  
L. Kolehmainen ◽  
H. Zech ◽  
D. von Wettstein
Keyword(s):  
Endoplasmic Reticulum ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Electron Scattering ◽  
Osmium Tetroxide ◽  
Crystal Formation ◽  
Mesophyll Cells ◽  
Virus Particles ◽  
Flexible Rods ◽  
Late Stages

The submicroscopic organization of mesophyll cells from tobacco leaves systemically infected with tobacco mosaic virus (TMV) is described. After fixation with glutaraldehyde and osmium tetroxide the arrangement of the TMV particles within the crystalline inclusions is well preserved. Only the ribonucleic acid-containing core of the virus particles is visible in the micrographs. Besides the hexagonal virus crystals, several characteristic types of "inclusion bodies" are definable in the cytoplasm: The so-called fluid crystals seem to correspond to single layers of oriented TMV particles between a network of the endoplasmic reticulum and ribosomes. Unordered groups or well oriented masses of tubes with the diameter of the TMV capsid are found in certain areas of the cytoplasm. A complicated inclusion body is characterized by an extensively branched and folded part of the endoplasmic reticulum, containing in its folds long aggregates of flexible rods. Certain parts of the cytoplasm are filled with large, strongly electron-scattering globules, probably of lipid composition. These various cytoplasmic differentiations and the different forms of presumed virus material are discussed in relation to late stages of TMV reproduction and virus crystal formation.

Three-dimensional reconstruction of the stacked-disk aggregate of tobacco mosaic virus protein from electron micrographs

1971 ◽  
Vol 261 (837) ◽  
pp. 211-219 ◽  
Keyword(s):  
Electron Microscope ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Virus Protein ◽  
Protein Subunits ◽  
Microscope Images ◽  
Dimensional Reconstruction ◽  
Inner Parts

The three-dimensional structure of the stacked-disk rod of tobacco mosaic virus protein has been reconstructed to a resolution of about 2 nm from electron microscope images. Closed rings of seventeen protein subunits (compared with 16 ⅓ in one turn of the virus helix) are stacked in polar fashion, the stacking being accompanied by an axial perturbation of periodicity 5.3 nm connecting successive pairs of rings into disks. The axial perturbation consists of a movement towards each other of the outer parts of the subunits in the two rings comprising a disk, together with a movement of the inner parts in the opposite direction. This could be explained either by a bending of parts of the subunits in the appropriate directions or by a bodily tilting of the subunits in the two rings in opposite directions.

scholarly journals Tobacco mosaic virus: a pioneer to cell–to–cell movement

1999 ◽  
Vol 354 (1383) ◽  
pp. 637-643 ◽  
Author(s):  
Vitaly Citovsky
Keyword(s):  
Cell Wall ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Movement ◽  
Host Cells ◽  
Specific Cell ◽  
Viral Movement Protein ◽  
Rna Molecules ◽  
Rna Complexes

Cell–to–cell movement of tobacco mosaic virus (TMV) is used to illustrate macromolecular traffic through plant intercellular connections, the plasmodesmata. This transport process is mediated by a specialized viral movement protein, P30. In the initially infected cell, P30 is produced by transcription of a subgenomic RNA derived from the invading virus. Presumably, P30 then associates with a certain proportion of the viral RNA molecules, sequestering them from replication and mediating their transport into neighbouring uninfected host cells. This nucleoprotein complex is targeted to plasmodesmata, possibly via interaction with the host cell cytoskeleton. Prior to passage through a plasmodesma, the plasmodesmal channel is dilated by the movement protein. It is proposed that targeting of P30–TMV RNA complexes to plasmodesmata involves binding to a specific cell wall–associated receptor molecule. In addition, a cell wall–associated protein kinase, phosphorylates P30 at its carboxy–terminus and minimizes P30–induced interference with plasmodesmatal permeability during viral infection.

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