The Effect of Urea on Tobacco Mosaic Virus: Polarity of Disassembly

Blowers, L. E.; Wilson, Theresa

doi:10.1099/0022-1317-61-1-137

Cited by 17 publications

(9 citation statements)

References 12 publications

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“…In vitro it has been shown that many agents (alkali, urea, DMSO and SDS) cause 300 nm TMV particles to disassemble progressively from the 5' end of the RNA Wilson et al, 1976Wilson et al, , 1981Blowers & Wilson, 1982), implying that protein-RNA interactions are intrinsically relatively weak at this end. Until now, only fairly extensive uncoating of TMV RNA (for 2 kb or more) has been detected.…”

Section: Introductionmentioning

confidence: 99%

Complete uncoating of the 5' leader sequence of tobacco mosaic virus RNA occurs rapidly and is required to initiate cotranslational virus disassembly in vitro

Mundry

Watkins²,

Ashfield³

et al. 1991

Journal of General Virology

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Destabilizing events required for subsequent cotranslational disassembly of tobacco mosaic virus (TMV) particles in vitro were studied. Brief treatment of U32p-labelled TMV (strain vulgate or U2) with 1% SDS exposed only 2.5 % of the RNA (160 5' nucleotides) in a susceptible subpopulation of virions. Limited uncoating occurred almost immediately and appeared to be synchronous because the amount of 5' oligonucleotide marker (t2) recovered remained constant throughout a 15 min period in SDS. Additional RNase Tl-sensitive oligonucleotides were exposed only after 1 to 2 min in SDS. Coat protein (CP) subunits released from virions 'destabilized' by ultracentrifugation at between pH 7-2 and 9.2 were quantified using L-[35S]methioninelabelled particles of TMV strain U2. CP recovery and virus particle translation results were consistent with increasing numbers of virions uncoating for approximately 200 nucleotides. In the presence of sparsomycin (SPN), the TMV strain vulgare 5' leader and the first AUG codon can bind two 80S ribosomes. Electron microscopy of pH 7-5-treated TMV particles incubated in SPN-treated wheatgerm extract or rabbit reticulocyte lysate, showed that approximately 10 % of virions complexed with one ribosome and approximately 10 % with two bound ribosomes, confirming that f2 at least had been uncoated. Nucleocapsids in these complexes were shorter than untreated TMV by 9 to 10 nm (i.e. equivalent to 192 to 217 nucleotides exposed). The template activities of virions pretreated at pH 7-2 to 9-2 were destroyed by RNase H when short cDNAs were hybridized to sequences at, or immediately 3' to, the first AUG codon. We propose that the complete 5' leader ofTMV RNA interacts weakly with CP subunits and that this micro-instability is due to the absence of G residues and is essential for initiation of cotranslational virus disassembly.

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Section: Introductionmentioning

confidence: 99%

Complete uncoating of the 5' leader sequence of tobacco mosaic virus RNA occurs rapidly and is required to initiate cotranslational virus disassembly in vitro

Mundry

Watkins²,

Ashfield³

et al. 1991

Journal of General Virology

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“…It has been shown that the stripping of TMV CP subunits from the 5′ end of RNA is induced by urea, DMSO (dimethyl sulfoxide), alkali, and detergent [28, 29]. Polar stripping results in the production of rods with a tail of RNA protruding from one end.…”

Section: Resultsmentioning

confidence: 99%

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

Drygin

Кондакова

Atabekov

2013

Advances in Virology

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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 of in vitro assembled 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.

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“…These data highlight the relevance of axial interactions in disassembly, as proposed in classical studies of TMV particle disassembly. Disassembly proceeds in an orderly manner, mainly from the end of the rod corresponding to the 5= end of the virus RNA (59)(60)(61), suggesting that it is due primarily to the destabilization of axial interactions among CP subunits. The most stable mutant, MG-(T43KϩD50G), is able to establish more ionic pairs, more H bonds, and more contacts with its neighbor subunits than MG-WT.…”

Section: Discussionmentioning

confidence: 99%

“…Virus particles were purified simultaneously for all genotypes from N. clevelandii-infected plants, and particle stability was analyzed by incubating 200 g of particles under different conditions. For stability at basic pH, particles were incubated in 0.1 M Tris-HCl (pH 8.75) on ice for different times (5,10,15,30,45,60,90, and 120 min), and the process of disassembly was stopped by addition of MgCl 2 to a final concentration of 50 mM (59). For analysis of stability at high ionic strength, particles were incubated in 6 M urea (pH 7.4) in phosphate buffer on ice for 5, 10, 15, 30, 45, 60, and 90 min, with disassembly being stopped by adding two volumes of 20 mM phosphate buffer, pH 6.9 (60).…”

Section: Methodsmentioning

confidence: 99%

Pleiotropic Effects of Resistance-Breaking Mutations on Particle Stability Provide Insight into Life History Evolution of a Plant RNA Virus

Bera

Moreno‐Pérez

García-Figuera

et al. 2017

J Virol

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In gene-for-gene host-virus interactions, virus evolution to infect and multiply in previously resistant host genotypes, i.e., resistance breaking, is a case of host range expansion, which is predicted to be associated with fitness penalties. Negative effects of resistance-breaking mutations on within-host virus multiplication have been documented for several plant viruses. However, understanding virus evolution requires analyses of potential trade-offs between different fitness components. Here we analyzed whether coat protein (CP) mutations in Pepper mild mottle virus that break L-gene resistance in pepper affect particle stability and, thus, survival in the environment. For this purpose, CP mutations determining the overcoming of L 3 and L 4 resistance alleles were introduced in biologically active cDNA clones. The kinetics of the in vitro disassembly of parental and mutant particles were compared under different conditions. Resistance-breaking mutations variously affected particle stability. Structural analyses identified the number and type of axial and side interactions of adjacent CP subunits in virions, which explained differences in particle stability and contribute to understanding of tobamovirus disassembly. Resistance-breaking mutations also affected virus multiplication and virulence in the susceptible host, as well as infectivity. The sense and magnitude of the effects of resistance-breaking mutations on particle stability, multiplication, virulence, or infectivity depended on the specific mutation rather than on the ability to overcome the different resistance alleles, and effects on different traits were not correlated. Thus, the results do not provide evidence of links or trade-offs between particle stability, i.e., survival, and other components of virus fitness or virulence.IMPORTANCE The effect of survival on virus evolution remains underexplored, despite the fact that life history trade-offs may constrain virus evolution. We approached this topic by analyzing whether breaking of L-gene resistance in pepper by Pepper mild mottle virus, determined by coat protein (CP) mutations, is associated with reduced particle stability and survival. Resistance-breaking mutations affected particle stability by altering the interactions between CP subunits. However, the sense and magnitude of these effects were unrelated to the capacity to overcome different resistance alleles. Thus, resistance breaking was not traded with survival. Resistance-breaking mutations also affected virus fitness within the infected host, virulence, and infectivity in a mutation-specific manner. Comparison of the effects of CP mutations on these various traits indicates that there are neither trade-offs nor positive links between survival and other life history traits. These results demonstrate that trade-offs between life history traits may not be a general constraint in virus evolution.

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The Effect of Urea on Tobacco Mosaic Virus: Polarity of Disassembly

Cited by 17 publications

References 12 publications

Complete uncoating of the 5' leader sequence of tobacco mosaic virus RNA occurs rapidly and is required to initiate cotranslational virus disassembly in vitro

Complete uncoating of the 5' leader sequence of tobacco mosaic virus RNA occurs rapidly and is required to initiate cotranslational virus disassembly in vitro

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

Pleiotropic Effects of Resistance-Breaking Mutations on Particle Stability Provide Insight into Life History Evolution of a Plant RNA Virus

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