Abstract
Contrary to a previous report, electron microscopic studies on the Fny strain of cucumber mosaic virus (CMV)-infected tobacco tissues revealed that plasmodesmata were not structurally modified during CMV infection, nor were virions ever observed in plasmodesmata connecting infected cells. To further explore the basis of CMV infection, experiments were performed on the CMV 3a ORF. The 3a protein of CMV was expressed in and purified from Escherichia coli. The purified protein was labeled with fluorescein isothiocyanate (FITC) and subsequently microinjected into mesophyll cells of mature leaves of Nicotiana tabacum cv. Turkish Samsun NN. Within a brief period (as little as 1 sec), the microinjected FITC-labeled CMV 3a protein moved into neighboring cells. Co-injection of unlabeled CMV 3a protein with 9.4-kDa fluorescein-conjugated dextran (F-dextran) resulted in extensive cell-to-cell movement (diffusion) of the F-dextran, indicating that the 3a protein can interact with and dilate plasmodesmata. Furthermore, co-injection of unlabeled 3a protein with fluorescently labeled infectious CMV RNA molecules resulted in rapid and extensive cell-to-cell transport. In contrast, a mutant form of the 3a protein was unable to traffic from cell to cell, to increase the size exclusion limit of plasmodesmata, or to potentiate cell-to-cell trafficking of CMV RNA molecules. Microinjection studies performed on transgenic tobacco plants expressing the CMV 3a protein indicated that fluorescently labeled CMV RNA moved out of the target cell into the surrounding mesophyll tissue. In addition, expression of the CMV 3a protein also potentiated the cell-to-cell movement of 9.4-kDa F-dextran. Collectively, these results provide direct experimental evidence that the CMV 3a protein functions as the movement protein of CMV. These findings are consistent with the hypothesis that CMV moves from cell-to-cell in the form of a ribonucleoprotein complex.
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Claims 8
Claim · model-written summary
CMV infection did not structurally modify tobacco plasmodesmata.
- Taxon
- tobacco
Nicotiana tabacumt0 - Interactor
- CMV
cucumber mosaic cucumoviruse0pathogen - Outcome
- plasmodesmata were not structurally modifiede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“plasmodesmata were not structurally modified during CMV infection”
t0“Tobacco Plants”
Claim · model-written summary
Virions were not observed in plasmodesmata between infected tobacco cells.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- CMVcucumber mosaic cucumovirust0pathogen
- Outcome
- virions ever observed in plasmodesmata connecting infected cellse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nor were virions ever observed in plasmodesmata connecting infected cells”
t0“CMV RNA in Tobacco Plants”
Claim · model-written summary
Microinjected CMV 3a protein moved into adjacent tobacco cells within as little as one second.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- CMVcucumber mosaic cucumoviruse0pathogen
- Gene
- CMV 3a proteine0
- Outcome
- moved into neighboring cellse0
- Value
- 1 sece0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Within a brief period (as little as 1 sec), the microinjected FITC-labeled CMV 3a protein moved into neighboring cells.”
t0“Tobacco Plants”
Claim · model-written summary
CMV 3a protein enabled extensive movement of F-dextran between tobacco cells.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- Co-injection of unlabeled CMV 3a protein with 9.4-kDa fluorescein-conjugated dextran (F-dextran)e0
- Interactor
- CMVcucumber mosaic cucumoviruse0pathogen
- Gene
- CMV 3a proteine0
- Outcome
- cell-to-cell movement (diffusion) of the F-dextrane0
- Direction
- extensivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Co-injection of unlabeled CMV 3a protein with 9.4-kDa fluorescein-conjugated dextran (F-dextran) resulted in extensive cell-to-cell movement (diffusion) of the F-dextran”
t0“Tobacco Plants”
Claim · model-written summary
Co-injected CMV 3a protein enabled rapid and extensive cell-to-cell transport of CMV RNA.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- co-injection of unlabeled 3a protein with fluorescently labeled infectious CMV RNA moleculese0
- Interactor
- CMVcucumber mosaic cucumoviruse0pathogen
- Gene
- 3a proteine0
- Outcome
- cell-to-cell transporte0
- Direction
- rapid and extensivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“co-injection of unlabeled 3a protein with fluorescently labeled infectious CMV RNA molecules resulted in rapid and extensive cell-to-cell transport”
t0“CMV RNA in Tobacco Plants”
Claim · model-written summary
Mutant CMV 3a protein failed to move between tobacco cells, dilate plasmodesmata, or promote CMV RNA trafficking.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- CMVcucumber mosaic cucumoviruse0pathogen
- Gene
- 3a proteine0
- Outcome
- unable to traffic from cell to cell, to increase the size exclusion limit of plasmodesmata, or to potentiate cell-to-cell trafficking of CMV RNA moleculese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a mutant form of the 3a protein was unable to traffic from cell to cell, to increase the size exclusion limit of plasmodesmata, or to potentiate cell-to-cell trafficking of CMV RNA molecules”
t0“Tobacco Plants”
Claim · model-written summary
In transgenic tobacco expressing CMV 3a, labeled CMV RNA moved into surrounding mesophyll tissue.
- Taxon
- tobaccoNicotiana tabacumt0
- Organ / stage
- mesophyll tissuee0
- Interactor
- CMVcucumber mosaic cucumoviruse0pathogen
- Outcome
- fluorescently labeled CMV RNA moved out of the target cell into the surrounding mesophyll tissuee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fluorescently labeled CMV RNA moved out of the target cell into the surrounding mesophyll tissue”
t0“Tobacco Plants”
Claim · model-written summary
CMV 3a expression promoted movement of F-dextran between tobacco cells.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- CMVcucumber mosaic cucumoviruse0pathogen
- Gene
- CMV 3a proteine0
- Outcome
- cell-to-cell movement of 9.4-kDa F-dextrane0
- Direction
- potentiatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“expression of the CMV 3a protein also potentiated the cell-to-cell movement of 9.4-kDa F-dextran”
t0“Tobacco Plants”
The same questions in other papers
Cucumis sativus · cucumber mosaic cucumovirus · Nicotiana tabacum (tobacco)Positive and negative results
5 papers in the same direction as this paper · 8 in the opposite direction
- negative
- negative
- negative
10 papers more in this group
See all 14 papers →infection · cucumber mosaic cucumovirus · Nicotiana tabacum (tobacco)Positive and negative results
1 paper in the same direction as this paper · 2 in the opposite direction
- negative
- negative
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.