scholarly journals Expression of the mouse p53 cellular tumor antigen in monkey cells.

1984 ◽  
Vol 4 (10) ◽  
pp. 2180-2186 ◽  
Author(s):  
O Pinhasi ◽  
M Oren
Keyword(s):  
Tumor Antigen ◽  
Recombinant Dna ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Reading Frame ◽  
Recombinant Plasmids ◽  
Cos Cells ◽  
In Cells

DNA specific for the murine p53 cellular tumor antigen was linked to the early simian virus 40 promoter and introduced into monkey COS cells either by transfection with recombinant plasmids or by infection with virus. Recipient cells made substantial amounts of a protein apparently identical to mouse p53. Severalfold-larger quantities were detected when cells were transfected with an intron-containing p53-specific segment, as compared with transfection with intronless cDNA. The p53 encoded by the recombinant DNA was capable of complexing with the simian virus 40 T antigen. Transfected p53 was also probably associated with a cellular 68-kilodalton protein, which may be related to a protein coprecipitating with p53 in some transformed cells. These findings confirm the predicted reading frame and protein boundaries and demonstrate that apparently functional p53 can be produced in cells via experimentally introduced recombinant DNA.

Expression of the mouse p53 cellular tumor antigen in monkey cells

1984 ◽  
Vol 4 (10) ◽  
pp. 2180-2186
Author(s):  
O Pinhasi ◽  
M Oren
Keyword(s):  
Tumor Antigen ◽  
Recombinant Dna ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Reading Frame ◽  
Recombinant Plasmids ◽  
Cos Cells ◽  
In Cells

DNA specific for the murine p53 cellular tumor antigen was linked to the early simian virus 40 promoter and introduced into monkey COS cells either by transfection with recombinant plasmids or by infection with virus. Recipient cells made substantial amounts of a protein apparently identical to mouse p53. Severalfold-larger quantities were detected when cells were transfected with an intron-containing p53-specific segment, as compared with transfection with intronless cDNA. The p53 encoded by the recombinant DNA was capable of complexing with the simian virus 40 T antigen. Transfected p53 was also probably associated with a cellular 68-kilodalton protein, which may be related to a protein coprecipitating with p53 in some transformed cells. These findings confirm the predicted reading frame and protein boundaries and demonstrate that apparently functional p53 can be produced in cells via experimentally introduced recombinant DNA.

Functional simian virus 40 T antigen is expressed in hybrid cells having finite proliferative potential

1987 ◽  
Vol 7 (4) ◽  
pp. 1541-1544
Author(s):  
O M Pereira-Smith ◽  
J R Smith
Keyword(s):  
Dna Synthesis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Proliferative Potential ◽  
Hybrid Cells ◽  
Ras Oncogenes ◽  
Immortal Cells ◽  
Cellular Dna

Simian virus 40-transformed human cells fused with other independently derived simian virus 40-transformed cells and tumor-derived cells containing activated H-ras and N-ras oncogenes yielded hybrids capable of indefinite division. Fusions with various other immortal cells yielded hybrids that had limited division potential. T antigen expressed in limited-division hybrids was functional for the induction of cellular DNA synthesis.

scholarly journals New Insights into the Mechanism of Inhibition of p53 by Simian Virus 40 Large T Antigen

1999 ◽  
Vol 19 (4) ◽  
pp. 2746-2753 ◽  
Author(s):  
Hilary M. Sheppard ◽  
Siska I. Corneillie ◽  
Christine Espiritu ◽  
Andrea Gatti ◽  
Xuan Liu
Keyword(s):  
Tumor Antigen ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Human Cells ◽  
Transactivation Domain ◽  
Large T Antigen ◽  
Large Tumor ◽  
Mechanism Of Inhibition ◽  
Mouse Cells

ABSTRACT Simian virus 40 (SV40) large tumor antigen (T antigen) has been shown to inhibit p53-dependent transcription by preventing p53 from binding to its cognate cis element. Data presented in this report provide the first direct functional evidence that T antigen, under certain conditions, may also repress p53-dependent transcription by a mechanism in which the transactivation domain of p53 is abrogated while DNA binding is unaffected. Specifically, p53 purified as a complex with T antigen from mouse cells was found to bind DNA as a transcriptionally inactive intact complex, while that purified from human cells was found to bind DNA independently of T antigen and could activate p53-dependent transcription. This difference in activity may be dependent on a different interaction of T antigen with mouse and human p53 and, in addition, on the presence of super T, which is found only in transformed rodent cells. These results suggest that subtle yet important differences exist between the inhibition of p53 by T antigen in mouse and human cells. The implications of this finding with respect to SV40-associated malignancies are discussed.

scholarly journals Neoplastic transformation of rat 3Y1 cells by a transcriptionally activated human c-myc gene and stabilization of p53 cellular tumor antigen in the transformed cells.

1986 ◽  
Vol 6 (12) ◽  
pp. 4379-4386 ◽  
Author(s):  
K Shiroki ◽  
K Segawa ◽  
Y Koita ◽  
M Shibuya
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Tumor Antigen ◽  
Simian Virus 40 ◽  
Soft Agar ◽  
Simian Virus ◽  
Transformed Cells ◽  
Agar Culture ◽  
Myc Gene ◽  
Tumorigenic Cell Line

Transformed foci were obtained in rat 3Y1 fibroblasts cotransfected with pRmyc 27 (transcriptionally activated c-myc) and pSV2neo DNA. RmycY cell lines (1 to 7) were established from these foci. RmycY cells were small and round and contained enlarged nucleoli in the nucleus. The myc gene was expressed in these cell lines at a much higher level than in 3Y1 cells and at a level similar to that in HL-60 cells. These cell lines formed colonies in soft-agar culture and tumors in syngeneic rats transplanted with RmycY cells. Expression of the gene and colony formation in soft-agar culture were analyzed in subclones from RmycY cell line 1. A correlation between myc gene expression and the ability to form colonies in soft-agar culture was observed in these cells. Antibody against p53 cellular tumor antigen was detected in some sera from tumor-bearing rats. p53 cellular tumor antigen stabilized and accumulated in RmycY cells to the same extent as in simian virus 40-transformed cells. The results suggest that elevated c-myc expression and an increased amount of p53 cause 3Y1 cells to become a more tumorigenic cell line.

scholarly journals Establishment of rat pancreatic endocrine cell lines by infection with simian virus 40

1979 ◽  
Vol 178 (3) ◽  
pp. 559-568 ◽  
Author(s):  
E J Niesor ◽  
C B Wollheim ◽  
D H Mintz ◽  
B Blondel ◽  
A E Renold ◽  
...  
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Culture Conditions ◽  
T Antigen ◽  
Insulin Biosynthesis ◽  
Transformed Cells ◽  
Immunoreactive Insulin ◽  
Gel Chromatography ◽  
Pancreatic Cells

The feasibility of infection and transformation by SV40 (simian virus 40) of primary cell cultures derived from newborn-rat pancreas was investigated. As judged by the presence of intranuclear SV40 T-antigen, exposure to the virus resulted specifically in infection and transformation of epithelioid (predominantly endocrine) cells. The transformed cells were subcultured (more than 64 passages) and cloned. Culture medium and acid/ethanol extracts of the cells did not contain detectable amounts of immunoreactive insulin after the third subculture. However, inoculation of such SV40-transformed pancreatic cells into immunodeficient rats results in tumours in which insulin production was partially restored through the passage in vivo, since the tumour cells contained and synthesized small amounts of immunoreactive insulin which co-migrated with an insulin marker on gel chromatography. Interestingly, the transformed cells maintained under tissue-culture conditions produced a protein immunologically related to insulin, soluble in aqueous buffer but insoluble in acid/ethanol. This 3000-dalton protein is too large to be a translation product of the rat preproinsulin 9S mRNA. SV40-transformed pancreatic cells might prove useful in the investigation of the factors controlling and maintaining insulin biosynthesis.

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