Induced Enzyme Formed on Bacterial Polyribosomes

Kiho, Yukio; Rich, Alexander

doi:10.1073/pnas.51.1.111

Cited by 126 publications

(38 citation statements)

References 16 publications

(4 reference statements)

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“…Polyribosomal distribution in tobacco leaves is very similar to that which is seen in other organisms [8,14,16]. Upon infection of TMV, a new polyribosome is observed which has an S value of around 360-380.…”

Section: Discussionsupporting

confidence: 54%

“…Upon infection of TMV, a new polyribosome is observed which has an S value of around 360-380. Deducing from the extensive works on the size of mammalian [11,15] and E. coli [8] polyribosomes and judging by the sedimentation constant of 360-380 S, this TMV-specific polyribosome would contain 60-80 ribosomes. The penta-ribosomal polyribosome found in the reticulocyte contains about 450 nucleotides to hold the structural information required to synthesize the hemoglobin polypeptide chain [22].…”

Section: Discussionmentioning

confidence: 99%

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Isolation of Polyribosome from Tobacco Plants Infected with Tobacco Mosaic Virus

Kiho

1968

Japanese Journal of Microbiology

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Isolation of Polyribosome from Tobacco Plants Infected with Tobacco Mosaic Virus

Kiho

1968

Japanese Journal of Microbiology

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“…A previous method [5] was modified as follows: 1 gram of lamina tissue obtained from young leaves was ground with a mortar and pestle in 1 ml of TrisMg-KC1 buffer (0.005 M Tris, pH 7.4, 0.001 M MgC12 and 0.06 M KC1) containing yeast RNA, 1 mg/ml. After grinding, another 1 ml of the above buffer containing Triton X-100, 5% [14] and Brij 58, 1% [7] was added. The mixture was stirred gently and sodium deoxycholate (DOC) was added to a final concentration of 2%.…”

Section: And Methodsmentioning

confidence: 99%

Polysomes Containing Infecting Viral Genome in Tobacco Leaves Infected with Tobacco Mosaic Virus

Kiho

1970

Japanese Journal of Microbiology

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This study concerns the interaction between parental virus RNA and host cell components in tobacco leaves infected with tobacco mosaic virus (TMV). By using a gentle method for disruption, extracts were obtained from tobacco leaves infected with 32P-labelled TMV and the fate of infecting parental 32P-TMV-RNA was studied. Sucrose gradient centrifugation analysis showed that the parental "P-RNA distributed into four regions: free RNA, partially uncoated TMV, TMV and a structure heavier than TMV. The heavier structure was considered to be polysomes carrying the parental TMV-RNA as messenger RNA based on its size, sensitivity to RNase, dependence of its formation on protein synthesis and the kinetics of its appearance after infection. Control experiments were done to exclude the possibility that the structure is not an artifact aggregate produced by an interaction between partially uncoated virus or its RNA and host cell components. Polysomes containing TMV-RNA were found as membrane bound forms. Based on these data, it is suggested that uncoating of TMV and formation of polysomes are closely related and evidence has been obtained which suggests that uncovering of the viral genome and its translation takes place hand-in-hand on a single virion.As the efficiency of infection of tobacco mosaic virus (TMV) is extremely low, usually one local lesion per 105-106 virus particles inoculated [13], it has been thought that only limited biochemical studies might be performed on the fate of infecting TMV after inoculation of tobacco leaves. However, some recent works have shown that almost all TMV particles retained by the leaves after inoculation are at least partially uncoated [4,8,10,11]. These reports stimulated us to study the fate of infecting TMV. This paper is concerned with the interaction of infecting parental viral RNA with host cell components as studied by density gradient centrifugation analysis of the extracts obtained from infected leaves.The method for the preparation of cell extracts plays a critical role in this type of investigation. In the present study several methods for preparing extracts of tobacco leaves were examined by monitoring the yield of polysomes. A polysome, the site of protein synthesis, is an aggregate of ribosomes which are linked together by messenger RNA and is hence destroyed easily by shearing force or by action of RNase [18]. This structure seems, therefore, to be particularly suitable as a criterion to study the appropriateness of the method for iso-291

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“…One of the basic differences between biosynthetic protein folding and protein renaturation is cotranslational folding, folding that occurs during synthesis. The elegant idea that the process of protein folding is concomitant with synthesis was articulated, and experimental testing was begun in the early 1960s (1,2). Today there is substantial experimental support for the cotranslational folding hypothesis.…”

mentioning

confidence: 99%