Modulation of p53 protein expression during cellular transformation with simian virus 40

1987 ◽  
Vol 7 (12) ◽  
pp. 4453-4463 ◽  
Author(s):  
W Deppert ◽  
M Haug ◽  
T Steinmayer
Keyword(s):  
Tumor Antigen ◽  
P53 Protein ◽  
Simian Virus 40 ◽  
Cellular Transformation ◽  
Simian Virus ◽  
Transformed Cells ◽  
Nonpermissive Temperature ◽  
3T3 Cells ◽  
Large Tumor ◽  
P53 Protein Expression

We analyzed the relation of metabolic stabilization of the p53 protein during cellular transformation by simian virus 40 (SV40) to (i) expression of the transformed phenotype and (ii) expression of the large tumor antigen (large T). Analysis of SV40-tsA28-mutant-transformed rat cells (tsA28.3 cells) showed that both p53 complexed to large T and free p53 (W. Deppert and M. Haug, Mol. Cell. Biol. 6:2233-2240, 1986) were metabolically stable when the cells were cultured at 32 degrees C and expressed large T and the transformed phenotype. At the nonpermissive temperature (39 degrees C), large-T expression is shut off in these cells and they revert to the normal phenotype. In such cells, p53 was metabolically unstable, like p53 in untransformed cells. To determine whether metabolic stabilization of p53 is directly controlled by large T, we next analyzed the metabolic stability of complexed and free p53 in SV40 abortively infected normal BALB/c mouse 3T3 cells. We found that neither p53 in complex with large T nor free p53 was metabolically stable. However, both forms of p53 were stabilized in SV40-transformed cells which had been developed in parallel from SV40 abortively infected cultures. Our results indicate that neither formation of a complex of p53 with large T nor large-T expression as such is sufficient for a significant metabolic stabilization of p53. Therefore, we suggest that metabolic stabilization of p53 during cellular transformation with SV40 is mediated by a cellular process and probably is the consequence of the large-T-induced transformed phenotype.

scholarly journals Modulation of p53 protein expression during cellular transformation with simian virus 40.

1987 ◽  
Vol 7 (12) ◽  
pp. 4453-4463 ◽  
Author(s):  
W Deppert ◽  
M Haug ◽  
T Steinmayer
Keyword(s):  
Tumor Antigen ◽  
P53 Protein ◽  
Simian Virus 40 ◽  
Cellular Transformation ◽  
Simian Virus ◽  
Transformed Cells ◽  
Nonpermissive Temperature ◽  
3T3 Cells ◽  
Large Tumor ◽  
P53 Protein Expression

We analyzed the relation of metabolic stabilization of the p53 protein during cellular transformation by simian virus 40 (SV40) to (i) expression of the transformed phenotype and (ii) expression of the large tumor antigen (large T). Analysis of SV40-tsA28-mutant-transformed rat cells (tsA28.3 cells) showed that both p53 complexed to large T and free p53 (W. Deppert and M. Haug, Mol. Cell. Biol. 6:2233-2240, 1986) were metabolically stable when the cells were cultured at 32 degrees C and expressed large T and the transformed phenotype. At the nonpermissive temperature (39 degrees C), large-T expression is shut off in these cells and they revert to the normal phenotype. In such cells, p53 was metabolically unstable, like p53 in untransformed cells. To determine whether metabolic stabilization of p53 is directly controlled by large T, we next analyzed the metabolic stability of complexed and free p53 in SV40 abortively infected normal BALB/c mouse 3T3 cells. We found that neither p53 in complex with large T nor free p53 was metabolically stable. However, both forms of p53 were stabilized in SV40-transformed cells which had been developed in parallel from SV40 abortively infected cultures. Our results indicate that neither formation of a complex of p53 with large T nor large-T expression as such is sufficient for a significant metabolic stabilization of p53. Therefore, we suggest that metabolic stabilization of p53 during cellular transformation with SV40 is mediated by a cellular process and probably is the consequence of the large-T-induced transformed phenotype.

scholarly journals Evidence for free and metabolically stable p53 protein in nuclear subfractions of simian virus 40-transformed cells.

1986 ◽  
Vol 6 (6) ◽  
pp. 2233-2240 ◽  
Author(s):  
W Deppert ◽  
M Haug
Keyword(s):  
Nuclear Matrix ◽  
P53 Protein ◽  
Simian Virus 40 ◽  
Cellular Transformation ◽  
Simian Virus ◽  
Cellular Protein ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Large Tumor ◽  
Nucleoplasmic Chromatin

To determine functional subcellular loci of p53, a cellular protein associated with cellular transformation, we analyzed the nucleoplasmic, chromatin, and nuclear matrix fractions from normal mouse 3T3 cells, from methylcholanthren-transformed mouse (MethA) cells, and from various simian virus 40 (SV40)-transformed cells for the presence of p53. In 3T3 and MethA cells, p53 was present in all nuclear subfractions, suggesting an association of p53 with different structural components of the nucleus. In 3T3 cells, p53 was rapidly turned over, whereas in MethA cells, p53 was metabolically stable. In SV40-transformed cells, p53 complexed to large tumor antigen (large T) was found in the nucleoplasmic and nuclear matrix fractions, as described previously (M. Staufenbiel and W. Deppert, Cell 33:173-181, 1983). In addition, however, metabolically stable p53 not complexed to large T (free p53) was also found in the chromatin and nuclear matrix fractions of these cells. This free p53 did not arise by dissociation of large T-p53 complexes, suggesting that stabilization of p53 in SV40-transformed cells can also occur by means other than formation of a complex with large T.

Evidence for free and metabolically stable p53 protein in nuclear subfractions of simian virus 40-transformed cells

1986 ◽  
Vol 6 (6) ◽  
pp. 2233-2240
Author(s):  
W Deppert ◽  
M Haug
Keyword(s):  
Nuclear Matrix ◽  
P53 Protein ◽  
Simian Virus 40 ◽  
Cellular Transformation ◽  
Simian Virus ◽  
Cellular Protein ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Large Tumor ◽  
Nucleoplasmic Chromatin

To determine functional subcellular loci of p53, a cellular protein associated with cellular transformation, we analyzed the nucleoplasmic, chromatin, and nuclear matrix fractions from normal mouse 3T3 cells, from methylcholanthren-transformed mouse (MethA) cells, and from various simian virus 40 (SV40)-transformed cells for the presence of p53. In 3T3 and MethA cells, p53 was present in all nuclear subfractions, suggesting an association of p53 with different structural components of the nucleus. In 3T3 cells, p53 was rapidly turned over, whereas in MethA cells, p53 was metabolically stable. In SV40-transformed cells, p53 complexed to large tumor antigen (large T) was found in the nucleoplasmic and nuclear matrix fractions, as described previously (M. Staufenbiel and W. Deppert, Cell 33:173-181, 1983). In addition, however, metabolically stable p53 not complexed to large T (free p53) was also found in the chromatin and nuclear matrix fractions of these cells. This free p53 did not arise by dissociation of large T-p53 complexes, suggesting that stabilization of p53 in SV40-transformed cells can also occur by means other than formation of a complex with large T.

scholarly journals Nonselective expression of simian virus 40 large tumor antigen fragments in mouse cells.

1982 ◽  
Vol 79 (6) ◽  
pp. 2064-2067 ◽  
Author(s):  
V. B. Reddy ◽  
S. S. Tevethia ◽  
M. J. Tevethia ◽  
S. M. Weissman
Keyword(s):  
Tumor Antigen ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Large Tumor ◽  
Large Tumor Antigen ◽  
Mouse Cells

Differential roles of heat shock protein 70 in the in vitro nuclear import of glucocorticoid receptor and simian virus 40 large tumor antigen

1994 ◽  
Vol 14 (8) ◽  
pp. 5088-5098
Author(s):  
J Yang ◽  
D B DeFranco
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Tumor Antigen ◽  
Nuclear Import ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Large Tumor ◽  
Large Tumor Antigen ◽  
Cell Cytosol

Nuclear import of glucocorticoid receptors (GRs) was analyzed in vitro with digitonin-permeabilized cells (S. A. Adam, R. Sterne-Marr, and L. Gerace, J. Cell Biol. 111:807-816, 1990). Indirect immunofluorescence methods were used to monitor the transport of GRs from rat hepatoma and fibroblast cell cytosol into HeLa nuclei. In vitro nuclear import of GRs was shown to be hormone dependent and to require ATP and incubation at ambient temperatures (i.e., 30 degrees C). Hormone-dependent dissociation of GR-bound proteins, such as the 90-kDa heat shock protein, hsp90, is part of an activation process that is obligatory for the expression of the receptor's DNA-binding activity. Inhibition of in vitro GR activation by Na2MoO4 blocked hormone-dependent nuclear import, demonstrating that receptor activation is required for nuclear import. The addition to GR-containing cytosol of antiserum directed against the cytosolic 70-kDa heat shock protein, hsp70, while effective in blocking the nuclear import of simian virus 40 large tumor antigen (SV40 TAg), did not affect hormone-dependent nuclear import of endogenous, full-length GRs or an exogenously added truncated GR protein (i.e., XGR556) that lacks a hormone-binding domain but possesses a constitutively active nuclear localization signal sequence (NLS). Depletion of hsp70 from HeLa cell cytosol did not affect the nuclear import of exogenously added XGR556 but led to inhibition of SV40 TAg nuclear import. Thus, two closely related NLSs, one contained within GRs and the other contained within SV40 TAg, are distinguished by their differential requirements for hsp70 in vitro.

scholarly journals Simian Virus 40 Large Tumor Antigen Modulates the Raf Signaling Pathway

2001 ◽  
Vol 276 (30) ◽  
pp. 27840-27845 ◽  
Author(s):  
Nicholas Grammatikakis ◽  
Katarzyna Jaronczyk ◽  
Aliki Siganou ◽  
Adina Vultur ◽  
Heather Lee Brownell ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Tumor Antigen ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Large Tumor ◽  
Large Tumor Antigen
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