Experimental evidence that polyoma-specific tumour antigen is a virus-coded protein

An isolation procedure for rat brain aldolase C has been developed which also permits the isolation of aldolase C from experimental hepatomas.Certain enzymatic properties (specific activity and Michaelis constant towards the two specific substrates : fructose 1,6-bisphosphate and fructose 1 -phosphate) and physico-chemical properties (molecular weight, N-terminal amino-acid) of the two enzymes have been studied and compared. Moreover, an amino-acid analysis has been carried out for rat brain aldolase C.Within experimental errors, the two enzymes appear to be identical.

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“…They are not the product of new genes, as are tumor neoantigens [36] which are probably coded by the virus integrated into the cell genome [37].…”

Section: Discussionmentioning

confidence: 99%

Purification of Aldolase C from Rat Brain and Hepatoma

Hatzfeld¹,

Élion²,

Mennecier³

et al. 1977

European Journal of Biochemistry

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“…The rise in activity of the DNA polymerases upon infection with SV40 appears to originate from modifications in cellular metabolism (1,4,5), such as the regulation of mRNA transcription, control of translation at the ribosomal level (28), modifications in the cellular membrane with the appearance of a viral-coded tumor antigen (29) and a change in the glyeotipid composition to resemble that found in cancerous tissue (30,31). Modifications in the cell membrane could readily effect the calcium ion balance which plays a pivotal role in.…”

Section: Diseussionmentioning

confidence: 99%

Fluctuation in activity of the molecular forms of cellular DNA polymerase during infection by SV40

Lazarus

Kitron

1976

Archives of Virology

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Infection of BSC-1 cells by SV40 brings about an increase of 7--11-fold in DNA polymerase activity, found in the nuclei and cytoplasm, respectively. The overall ratio between activites of DNA polymerase beta (3.1S) and DNA polymerase alpha (5.5S) remains fairly constant throughout infection. However,there is a large increase in DNA polymerase alpha2 (7.1S) in the cytoplasm, and its appearance in the nuclei late in infection. The addition of 1 M NaCl to infected cytoplasm,causes an aggregation of DNA polymerase alpha into a higher sedimenting form (9.8S), termed DNA polymerase alpha3. DNA polymerase alpha1, alpha2 and alpha3 are different molecular forms of the same enzyme, as can be seen by their similar inhibition by N-ethyl-maleimide, heparin and NaCl. However, this new activity, alpha3, is stimulated by dithiothreitol to a greater extent at pH 9.30 than at pH 7.94. The conformational changes induced in DNA polymerase and its increase in activity during infection with SV40 are discussed.

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“…For many biological studies, it has been valuable to introduce cloned DNAs into cells cultured from higher organisms where a wide range of biological activities may be examined against the background of cellular regulation. Physical (5,8,29) as well as biological (9,18,30) techniques have proven effective in placing purified macromolecules into cultured cells. In this study, we demonstrate that the immediate fate of DNAs within recipient cells depends upon the technique used for their introduction.…”

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confidence: 99%

Differences in Intracellular DNA Ligation After Microinjection and Transfection

Kopchick

Stacey

1984

Molecular and Cellular Biology

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An uninterrupted avian sarcoma viral genome terminated by viral long terminal repeat sequences was cloned into a pBR322 plasmid. After introduction into a cultured avian cell, transcription of either the circular plasmid molecule or one linearized within the pBR322 sequences could initiate and terminate at long terminal repeat sequences, yielding full-sized viral RNA. A plasmid DNA molecule linearized by cleavage within the viral pol gene, on the other hand, would have to undergo ligation to yield full-sized viral RNA. Microinjection of each of these three types of DNA into the nuclei of quail cells promoted the release of similar virus titers, indicating that the plasmid DNA cleaved within the viral pol gene had been efficiently and accurately ligated. When plasmid DNA was transfected into quail cells, circular and pBR322-cleaved molecules directed the synthesis of similar virus titers, indicating that they were similarly taken up and utilized by the cells. Compared with these results, plasmid DNA cleaved within the pol gene was reduced in activity over 95% after transfection. This reduction did not result from inefficient ligation but from the generation of mutations (of limited size) during ligation of the transfected molecules. Mutations were not observed after microinjection even into the cytoplasm. Consistent with these findings, transfected DNA termini were found to be joined regardless of their structure, whereas ligation after microinjection required that single-stranded protruding DNA termini be complementary.

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Experimental evidence that polyoma-specific tumour antigen is a virus-coded protein

Cited by 20 publications

References 7 publications

Purification of Aldolase C from Rat Brain and Hepatoma

Purification of Aldolase C from Rat Brain and Hepatoma

Fluctuation in activity of the molecular forms of cellular DNA polymerase during infection by SV40

Differences in Intracellular DNA Ligation After Microinjection and Transfection

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