The effect of tobacco mosaic virus infection on host and virus-specific protein synthesis in protoplasts

Siegel, Albert; Hari, V.; Kolacz, Kathryn

doi:10.1016/0042-6822(78)90456-7

Cited by 71 publications

(30 citation statements)

References 21 publications

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“…Additionally, even though the 30-kDa protein is stably associated with the cell wall (9,10), it accumulates to relatively low levels, ==1% of total plant protein. In contrast, coat protein gene expression reaches a maximum 24-72 hr after infection and constitutes up to 70% of total plant protein synthesis (11). The 30-kDa and coat protein genes have several notable differences.…”

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confidence: 98%

Genomic position affects the expression of tobacco mosaic virus movement and coat protein genes.

Culver

Lehto

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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Alterations in the genomic position of the tobacco mosaic virus (TMV) genes encoding the 30-kDa cellto-cell movement protein or the coat protein greatly affected their expression. Higher production of 30-kDa protein was correlated with increased proximity of the gene to the viral 3' terminus. A mutant placing the 30-kDa open reading frame 207 nucleotides nearer the 3' terminus produced at least 4 times the wild-type TMV 30-kDa protein level, while a mutant placing the 30-kDa open reading frame 470 nucleotides doser to the 3' terminus produced at least 8 times the wild-type TMV 30-kDa protein level. Increases in 30-kDa protein production were not correlated with the subgenomic mRNA promoter (SGP) controlling the 30-kDa gene, since mutants with either the native 30-kDa SGP or the coat protein SGP in front of the 30-kDa gene produced similar levels of 30-kDa protein. Lack of coat protein did not affect 30-kDa protein expression, since a mutant with the coat protein start codon removed did not produce increased amounts of 30-kDa protein. Effects of gene positioning on coat protein expression were examined by using a mutant containing two different tandemly positioned tobamovirus (TMV and Odontoglossum ringspot virus) coat protein genes. Only coat protein expressed from the gene positioned nearest the 3' viral terminus was detected. Analysis of 30-kDa and coat protein subgenomic mRNAs revealed no proportional increase in the levels of mRNA relative to the observed levels of 30-kDa and coat proteins. This suggests that a translational mechanism is primarily responsible for the observed effect of genomic position on expression of 30-kDa movement and coat protein genes.Positive-sense RNA viruses have evolved numerous strategies for gene regulation. One common strategy is the use of subgenomic mRNAs, transcribed from genomic RNA, for the expression of internal open reading frames (ORFs). In this manner the expression of multiple genes residing on a common genomic RNA can be independently regulated. One such virus that utilizes this strategy is the type member of the tobamovirus group, tobacco mosaic virus (TMV).The genome of TMV resides on a single strand of positivesense RNA, 6395 nucleotides (nt) in length, and encodes at least four proteins (1). The TMV genome is organized such that two 5'-coterminal ORFs encoding 126-kDa and 18&-kDa replicase proteins are translated from the genomic RNA, while an internal ORF encoding the 30-kDa cell-to-cellmovement protein and a 3'-proximal ORF encoding the coat protein (structural) are translated from respective subgenomic mRNAs (2-5). A third subgenomic mRNA has been detected for an additional internal ORF, within the 183-kDa ORF, encoding a putative 54-kDa protein that has not yet been detected in infected plants (6). The TMV subgenomic mRNAs are transcribed from negative-sense genomic RNA and share a common 3' terminus.Of particular interest is that genes of TMV expressed via subgenomic mRNAs are independently regulated, both quantitatively and temporally. The 30-kDa pro...

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confidence: 98%

Genomic position affects the expression of tobacco mosaic virus movement and coat protein genes.

Culver

Lehto

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

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“…The MP also has the capacity to bind single-stranded nucleic acids in vitro (Citovsky et al, 1990), and since complexes of MP and viral RNA (vRNA) were isolated from TMV-infected plants (Dorokhov et al, 1983(Dorokhov et al, , 1984, vRNA movement likely occurs in the form of a ribonucleoprotein complex. Indeed, the viral capsid protein is dispensable for cell-to-cell movement (Siegel et al, 1978;Dawson et al, 1988;Saito et al, 1990;Hilf and Dawson, 1993), indicating that the virus moves between cells in a nonencapsidated form. During infection, the protein interacts with endoplasmic reticulum (ER) membranes and microtubules, suggesting a role of these cellular components in vRNA movement (Heinlein et al, 1995(Heinlein et al, , 1998.…”

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confidence: 99%

Inhibition of Tobacco Mosaic Virus Movement by Expression of an Actin-Binding Protein

et al. 2009

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The tobacco mosaic virus (TMV) movement protein (MP) required for the cell-to-cell spread of viral RNA interacts with the endoplasmic reticulum (ER) as well as with the cytoskeleton during infection. Whereas associations of MP with ER and microtubules have been intensely investigated, research on the role of actin has been rather scarce. We demonstrate that Nicotiana benthamiana plants transgenic for the actin-binding domain 2 of Arabidopsis (Arabidopsis thaliana) fimbrin (AtFIM1) fused to green fluorescent protein (ABD2:GFP) exhibit a dynamic ABD2:GFP-labeled actin cytoskeleton and myosin-dependent Golgi trafficking. These plants also support the movement of TMV. In contrast, both myosin-dependent Golgi trafficking and TMV movement are dominantly inhibited when ABD2:GFP is expressed transiently. Inhibition is mediated through binding of ABD2:GFP to actin filaments, since TMV movement is restored upon disruption of the ABD2:GFP-labeled actin network with latrunculin B. Latrunculin B shows no significant effect on the spread of TMV infection in either wild-type plants or ABD2:GFP transgenic plants under our treatment conditions. We did not observe any binding of MP along the length of actin filaments.Collectively, these observations demonstrate that TMV movement does not require an intact actomyosin system. Nevertheless, actin-binding proteins appear to have the potential to exert control over TMV movement through the inhibition of myosinassociated protein trafficking along the ER membrane.The mechanism by which plant viruses move from cell to cell and systemically to cause systemic infection has been the subject of intense studies (for review, see

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“…1A). The 126-kDa protein is translated from the first open reading frame (ORF) within the genomic RNA, and the 183-kDa protein is expressed via occasional readthrough of an amber stop codon (33). The 126-kDa protein is produced at levels 10 to 20 times higher than those at which the 183-kDa protein is produced.…”

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confidence: 99%

Conundrum of the Lack of Defective RNAs (dRNAs) Associated with Tobamovirus Infections: dRNAs That Can Move Are Not Replicated by the Wild-Type Virus; dRNAs That Are Replicated by the Wild-Type Virus Do Not Move

Knapp

Dawson

Lewandowski

2001

J Virol

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Two classes of artificially constructed defective RNAs (dRNAs) of Tobacco mosaic virus (TMV) were examined in planta with helper viruses that expressed one (183 kDa) or both (126 and 183 kDa) of the replicaseassociated proteins. The first class of artificially constructed dRNAs had the helicase and polymerase (POL) domains deleted; the second had an intact 126-kDa protein open reading frame (ORF). Despite extremely high levels of replication in protoplasts, the first class of dRNAs did not accumulate in plants. The dRNAs with an intact 126-kDa protein ORF were replicated at moderate levels in protoplasts and in planta when supported by a TMV mutant that expressed the 183-kDa protein but not the 126-kDa protein (183F). These dRNAs were not supported by helper viruses expressing both replicase-associated proteins. De novo dRNAs were generated in plants infected by 183F but not in plants infected with virus with the wild-type replicase. These novel dRNAs each contained a new stop codon near the location of the wild-type stop codon for the 126-kDa protein and had most of the POL domain deleted. The fact that only dRNAs that contained a complete 126-kDa protein ORF moved systemically suggests that expression of a functional 126-kDa protein or the presence of certain sequences and/or structures within this ORF is required for movement of dRNAs. At least two factors may contribute to the lack of naturally occurring dRNAs in association with wild-type TMV infections: an inability of TMV to support dRNAs that can move in plants and the inability of dRNAs that can be replicated by TMV to move in plants.

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The effect of tobacco mosaic virus infection on host and virus-specific protein synthesis in protoplasts

Cited by 71 publications

References 21 publications

Genomic position affects the expression of tobacco mosaic virus movement and coat protein genes.

Genomic position affects the expression of tobacco mosaic virus movement and coat protein genes.

Inhibition of Tobacco Mosaic Virus Movement by Expression of an Actin-Binding Protein

Conundrum of the Lack of Defective RNAs (dRNAs) Associated with Tobamovirus Infections: dRNAs That Can Move Are Not Replicated by the Wild-Type Virus; dRNAs That Are Replicated by the Wild-Type Virus Do Not Move

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