Reconstitution of Active Tobacco Mosaic Virus From Its Inactive Protein and Nucleic Acid Components

Fraenkel‐Conrat, H.; Williams, Robley C.

doi:10.1073/pnas.41.10.690

Cited by 567 publications

(234 citation statements)

References 6 publications

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“…That intact nucleic acids have a high degree of specificity in biological systems is evident both from the role of DNA in bacterial transformation (21), and of RNA in tobacco mosaic virus infection (22)(23)(24). In the amino acid incorporation system which we have described there is, as yet, no inkling of such specificity.…”

Section: Protein Syntkesis In Isolated Cell Nucleimentioning

confidence: 90%

Protein Synthesis in Isolated Cell Nuclei

Allfrey

Mirsky

Osawa

1957

The Journal of General Physiology

391

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The present communication deals with the ability of isolated nuclei to incorporate isotopically labelled amino acids into their proteins. It will be shown that the deoxyribonucleic acid of the nucleus plays a role in this incorporation; that protein synthesis virtually ceases when the DNA is removed from the nucleus, and that the uptake of amino acids resumes when the DNA is restored.This report also deals with the conditions necessary for amino acid incorporation, with the effects of various inhibitors, and with the role of nucleic acid components in this aspect of protein synthesis. Preliminary accounts of some of these experiments have been published elsewhere (1, 2). Sore, Properties of Isolated Thymus Nuclei.--Most of the experiments tobe described were performed on nuclei isolated from calf thymus tissue in 0.25 M sucrose solution containing a small amount of calcium chloride. The procedure is rapid and simple, and it provides nuclei of high purity in good yield.Since some form of standardization is essential for all work on isolated cell components, thymus nuclei isolated in sucrose have been compared with those isolated in non-aqueous media (3, 4). The purpose of this comparison is to test whether the aqueous isolation procedure extracts water-soluble nuclear components, or whether it leads to excessive contamination with the watersoluble proteins of the cytoplasm. Many such comparisons have shown that thymus "sucrose" nuclei are the equivalent of the standard "non-aqueous" nuclei in many respects. Their DNA content is the same (2.5 per cent DNA-P), as is their over-all protein composition and enzymic constitution (4).When preparations of thymus nuclei isolated in sucrose solution are examined under the light microscope, either stained or unstained, they seem to be a beautiful preparation. One observes great numbers of free nuclei, a few whole cells, and occasional red cells. Staining reveals occasional strands of cytoplasm attached to some of the nuclei. The over-aU extent of this cytoplasmic contamination can be estimated chemically [e.g. by nucleic acid analyses] and the conclusion was reached that these nuclei are better than 90 per cent pure.

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Section: Protein Syntkesis In Isolated Cell Nucleimentioning

confidence: 90%

Protein Synthesis in Isolated Cell Nuclei

Allfrey

Mirsky

Osawa

1957

The Journal of General Physiology

391

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“…However, several examples have been found at lower organizational levels. The tobacco mosaic virus is a well-known example of static self-assembly in biological systems [8]. Other examples at the cellular or intracellular level have been described, including the formation of filopodia and protein folding [9,10].…”

Section: Introductionmentioning

confidence: 99%

Capillary-based static self-assembly in higher organisms

Voise

Schindler

Casas

et al. 2011

J. R. Soc. Interface.

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Organized structures produced by dynamic self-assembly are often observed in animal groups. Static self-assembly, however, has to date only been observed at the cellular and sub-cellular levels. The aim of this study was to analyse organized structures in immobile whirligig beetle groups on the water surface. We used theoretical and computational approaches to model the meniscus around whirligig beetles and to calculate the surface energy for configurations involving two beetles. Theoretical predictions were then tested using live insects and resin casts. Observations were also made for three and more casts. The meniscus of whirligig beetles had a bipolar shape with two concave parts. For two beetles, predicted configurations based on energy minima corresponded to beetles in contact by their extremities, forming lines and arrows, and agreed well with observations. Experimental results for three and more beetle casts revealed new geometrical arrangements similar to those obtained with colloids at interfaces. This study provides the first example of static self-assembly at the inter-organism level and shows the importance of capillary interactions in such formations. We identify the ecological context in which our findings are of relevance.

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“…The RNA-protein affinity has in general both a non-specific, electrostatic component and a specific component with binding of particular RNA motifs such as "hairpins" to capsid proteins. Following the early work of Fraenkel-Conrat and Williams [10], it was found that many small RNA viruses can assemble spontaneously under in-vitro conditions in solutions containing the capsid proteins and the RNA genome molecules. The self-assembly of empty capsids has been shown to have the character of a first-order, activated process [11].…”

Section: Introductionmentioning

confidence: 99%

Orientational phase transitions and the assembly of viral capsids

et al. 2017

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We present a generalized Landau-Brazovskii free energy for the solidification of chiral molecules on a spherical surface in the context of the assembly of viral shells. We encounter two types of icosahedral solidification transitions. The first type is a conventional first-order phase transition from the uniform to the icosahedral state. It can be described by a single icosahedral spherical harmonic of even l. The chiral pseudo-scalar term in the free energy creates secondary terms with chiral character but it does not affect the thermodynamics of the transition. The second type, associated with icosahedral spherical harmonics with odd l, is anomalous. Pure odd l icosahedral states are unstable but stability is recovered if admixture with the neighboring l + 1 icosahedral spherical harmonic is included, generated by the non-linear terms. This is in conflict with the principle of Landau theory that symmetry-breaking transitions are characterized by only a single irreducible representation of the symmetry group of the uniform phase and we argue that this principle should be removed from Landau theory. The chiral term now directly affects the transition because it lifts the degeneracy between two isomeric mixed-l icosahedral states. A direct transition is possible only over a limited range of parameters. Outside this range, non-icosahedral states intervene. For the important case of capsid assembly dominated by l = 15, the intervening states are found to be based on octahedral symmetry.

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Reconstitution of Active Tobacco Mosaic Virus From Its Inactive Protein and Nucleic Acid Components

Cited by 567 publications

References 6 publications

Protein Synthesis in Isolated Cell Nuclei

Protein Synthesis in Isolated Cell Nuclei

Capillary-based static self-assembly in higher organisms

Orientational phase transitions and the assembly of viral capsids

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