An electrophoretic analysis of tobacco mosaic virus biosynthesis

Commoner, Barry; Newmark, Philip; Rodenberg, Sidney D.

doi:10.1016/0003-9861(52)90158-6

Cited by 28 publications

(8 citation statements)

References 6 publications

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“…Equivalent samples (about 8 gm. each) of infected and uninfected leaf blade tissue were prepared as described previously and cultured in nutrient solution under constant illumination at 24 ° C. (11).…”

Section: G Rdations Between Tke Biosyntkesis Of Tmv and Tke Non-virumentioning

confidence: 99%

Relationships Between Tobacco Mosaic Virus and the Non-Virus Proteins

Commoner¹,

Rodenberg²

1955

The Journal of General Physiology

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1. The non-virus proteins, A4, B3, and B6, characteristically found in tobacco leaf infected with TMV exhibit specific immunochemical cross-reactions with serum prepared against the virus. The close immunochemical relations which occur among these proteins do not extend to any normal tobacco leaf proteins. 2. The rate of appearance of the non-virus proteins in newly infected cultured leaf tissue at various times after inoculation has been determined by immunochemical techniques and by direct isolation of the proteins. Both methods give comparable results. The non-virus proteins appear abruptly at about 220 hours after inoculation, when the TMV content is about one-third its final value. The amount of A4 rises rapidly and then levels off. The B6 content rises rapidly and continuously over the course of the experiment. B3 appears last, and increases in amount considerably more slowly than A4 and B6. 3. The isotope contents of TMV, B3, and B6 which appear in given intervals after inoculation in newly infected leaf cultured in nutrient containing N15H4 have been compared. The isotope levels of concurrent TMV, B3, and B6 are identical within the experimental error. The isotope conditions employed in this experiment lead to the conclusion that this coincidence of N15 levels means that the virus and non-virus proteins are probably synthesized at about the same time from the same non-protein source of nitrogen. 4. Possible interpretations of the available data on the non-virus proteins are discussed. It is likely that one or more of these proteins represents small protein units which occur in the TMV nucleoprotein.As they exist in the infected leaf, the non-virus proteins are probably no longer available to the biochemical processes which lead to TMV synthesis. They are probably not precursors of TMV protein in a temporal sense.

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Section: G Rdations Between Tke Biosyntkesis Of Tmv and Tke Non-virumentioning

confidence: 99%

Relationships Between Tobacco Mosaic Virus and the Non-Virus Proteins

Commoner¹,

Rodenberg²

1955

The Journal of General Physiology

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“…In previous investigations it was shown that TMV synthesis withdraws nitrogen from the host's pool of non-protein nitrogen components (1,2), significantly alters host protein metabolism, and results in the appearance of at least one other abnormal protein in addition to TMV itself (3). The experiments reported in the present paper were designed to specify the non-protein source of TMV nitrogen and to elucidate the relationships between TMV biosynthesis and the protein metabolism of the host.…”

Section: Introductionmentioning

confidence: 99%

Relationships Between Tobacco Mosaic Virus Biosynthesis and the Nitrogen Metabolism of the Host

Commoner¹,

Schieber²,

Dietz³

1953

Journal of General Physiology

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1. Comparisons of the nitrogen content of TMV-infected and uninfected tobacco leaf discs at various times after inoculation show that virus synthesis is associated with a net increase in protein content. This excess protein is due to: (a) TMV, (b) an excess in insoluble protein which develops soon after inoculation and ends about 100 hours before cessation of TMV synthesis, and (c) an excess in soluble non-virus protein, which is variable in size and which only occurs during the time of virus synthesis. A deficiency in non-protein nitrogen occurs during the time when virus appears. 2. Isotope experiments with N15-labelled nutrient show that: (a) The bulk of TMV nitrogen is derived from the free ammonia of the host tissue. (b) Amino acid residues of TMV protein are not derived from the corresponding free amino acids in the host. (c) The appearance of TMV is preceded by the synthesis of an insoluble precursor of the virus which is then converted into TMV or some soluble intermediate protein. This effect is associated with a cell particulate which represents a small fraction of the total insoluble protein. (d) Infected tissue synthesizes de novo small amounts of soluble non-virus protein, which may represent intermediates in TMV synthesis. (e) Infected tissue fails to synthesize a rapidly turned-over soluble protein which is synthesized in comparable uninfected tissue. (f) TMV synthesis is preceded by a temporary enhancement of the metabolic stability of an insoluble protein component. 3. The results lead to the conclusion that TMV formation is due to diversion of some part of the host's protein-synthesizing apparatus from its normal course.

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“…Bawden and N . W. Pirie (Takahashi & Ishii, 1952;Commoner et al 1952;Jeener & Lemoine, 1953) were unanimous that their unsedimented antigen was not a nucleoprotein and contained no phosphorus. Repeated precipitation at pH 3.3 or from neutral solutions with ammonium sulphate, or sedimentation in the ultracentrifuge, did not alter the P content of preparations, and when sedimented in conditions which gave a compacted pellet and an uncompacted sediment, the P content of the two fractions did not differ by an amount exceeding the experimental error of determinations on small amounts of material containing so little P (Holden & Pirie , 1!355b).…”

Section: Puri$cation Of the Unsedimented Antigenmentioning

confidence: 99%

“…Little attention was given to non-infective material, and the emphasis laid on the homogeneity of purified preparations served only to strengthen the general assumption that viruses multiply by the replication of an infecting particle to give a result that is uniform except for occasional variants regarded as equivalent to mutations. When we (Bawden & Pirie, 1945a, b ) found that plants infected with the Rothamsted tobacco necrosis virus or with tobacco mosaic virus (TMV) contained more than one type of anomalous protein, we questioned the validity of this assumption, and have since argued (Bawden & Pirie, 1950a, b, 1952, 1953 that infection is more usefully regarded as a change in the protein metabolism of the host cells that leads to a variety of related though not identical particles. This idea a t first received little support but is now becoming more widely accepted, and other workers (Takahashi & Ishii, 1952, 1953Commoner, Newmark & Rodenberg, 1952;Jeener & Lemoine, 1953) have found that plants infected with TMV contain more than one type of specific particle.…”

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confidence: 99%

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Observations on the Anomalous Proteins Occurring in Extracts from Plants Infected with Strains of Tobacco Mosaic Virus

Bawden

Pirie

1956

Journal of General Microbiology

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SUMMARY: When extracts from plants infected with various strains of tobacco mosaic virus were ultracentrifuged, the non-infective supernatant fluids still contained 0.5-5 yo of the protein serologically related to the viruses. The small, mostly spherical, particles aggregated to form short rods as the antigen was progressively purified by precipitation with acid or salts. It formed long rods when heated in pH 5-5 buffer or when incubated with trypsin. *4s the particles increased in length, their serological behaviour in precipitation tests changed from ' somatic' to 'flagellar' type.Purified preparations of the unsedimented antigen from plants infected with either of two virus strains contained 0.1-0.2~0 phosphorus, seemingly in the form of a ribose nucleic acid. No evidence was obtained that the preparations were mixtures containing some particles with the 0-5 yo phosphorus characteristic of infective virus and some particles of protein free from nucleic acid.One virus strain produced a higher ratio than the others of unsedimented to sedirnented antigen. The amount of unsedimented antigen was correlated with the total content of anomalous protein when the protein was increasing rapidly, but later it fluctuated unpredictably. No conditions were found that consistently favoured its accumulation, but when plants systemically infected with the type strain were kept a t 36", the total amount of antigen decreased, while the amount unsedimented sometimes increased.The proportion of the total antigen now obtained as poorly infective nucleoprotein is much less than 10 years ago, when a third of it sedimented in the ultracentrifuge but failed to compact into a pellet. Now the uncompacted sediment, with all the host plants and virus strains used, contains only a trivial part of the total antigen.The virus released into sap when leaves are minced is, weight for weight, more infective than the virus that remains in the leaf residues until it is released by fine grinding.The early work on the anomalous protein contained in virus-infected plants was done primarily to identify material that could be related to the viruses themselves, and its main aim was to make preparations with the maximum infectivity and the minimum of different components. Little attention was given to non-infective material, and the emphasis laid on the homogeneity of purified preparations served only to strengthen the general assumption that viruses multiply by the replication of an infecting particle to give a result that is uniform except for occasional variants regarded as equivalent to mutations. When we (Bawden & Pirie, 1945a, b ) found that plants infected with the Rothamsted tobacco necrosis virus or with tobacco mosaic virus (TMV) contained more than one type of anomalous protein, we questioned the validity of this assumption, and have since argued (Bawden & Pirie, 1950a, b, 1952, 1953 that infection is more usefully regarded as a change in the protein metabolism

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An electrophoretic analysis of tobacco mosaic virus biosynthesis

Cited by 28 publications

References 6 publications

Relationships Between Tobacco Mosaic Virus and the Non-Virus Proteins

Relationships Between Tobacco Mosaic Virus and the Non-Virus Proteins

Relationships Between Tobacco Mosaic Virus Biosynthesis and the Nitrogen Metabolism of the Host

Observations on the Anomalous Proteins Occurring in Extracts from Plants Infected with Strains of Tobacco Mosaic Virus

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