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 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.

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 Isolation of cellular genes differentially expressed in mouse NIH 3T3 cells and a simian virus 40-transformed derivative: growth-specific expression of VL30 genes.

1985 ◽  
Vol 5 (10) ◽  
pp. 2590-2598 ◽  
Author(s):  
K Singh ◽  
S Saragosti ◽  
M Botchan
Keyword(s):  
Cell Lines ◽  
Simian Virus 40 ◽  
Mouse Cell ◽  
Simian Virus ◽  
Differentially Expressed ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Transformed Cell ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

We constructed and screened a cDNA library made from simian virus 40 (SV40)-transformed NIH 3T3 cells, and we isolated cDNAs representing genes that are differentially expressed between the parental cell and its SV40-transformed derivative. We found only a small number of cDNAs representing such genes. Two isolated cDNA clones represented RNAs expressed at elevated levels in the transformed cell line in a manner relatively independent of growth conditions. The expression of two other cDNAs was growth specific because transformed cells and nonconfluent parental cells contained higher levels of the homologous RNAs than did confluent, contact-inhibited parental cells. Another cDNA was well expressed in confluent parental and confluent transformed cells, but not in nonconfluent cells. The expression of some of these cDNAs varied strikingly in different mouse cell lines. Thus the genotype or histories of different cell lines can also affect the expression of certain genes. Interestingly, the only cDNA isolated that was expressed exclusively in the transformed cell was from an SV40 message. We focused on a growth-specific cDNA which we show is derived from a mouse endogenous retrovirus-like family called VL30. We sequenced the 3' long terminal repeat (LTR) of this transcriptionally active VL30 gene. This LTR has good homology with other VL30 LTR sequences, but differences occur, particularly upstream of the VL30 promoter. We found that VL30 gene expression varied in different mouse cell lines such that C3H cell lines had very low levels of VL30 transcripts relative to NIH 3T3 cell lines. However, Southern analysis showed that both cell lines had about the same number of VL30 genes homologous to our probe and that the position of the majority of these genes was conserved. We discuss possible explanations for this difference in VL30 expression.

scholarly journals Suppression of in vivo tumor formation induced by simian virus 40-transformed cells in mice receiving antiidiotypic antibodies.

1985 ◽  
Vol 161 (6) ◽  
pp. 1432-1449 ◽  
Author(s):  
R C Kennedy ◽  
G R Dreesman ◽  
J S Butel ◽  
R E Lanford
Keyword(s):  
Potential Role ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Cellular Protein ◽  
Tumor Formation ◽  
Transformed Cells ◽  
Antiidiotypic Antibodies ◽  
Carboxyl Terminal

This study characterizes four private idiotypes (Id) associated with monoclonal antibodies (mAb) to simian virus 40 (SV40) tumor antigen (T-Ag), and to a cellular protein, p53. Anti-Id recognized Id determinants associated with the antibody-combining site. BALB/c mice receiving a pool of anti-Id directed against mAb recognizing distinct amino and carboxyl terminal epitopes of T-Ag before receiving a tumorigenic dose of SV40-transformed cells showed suppression of tumor formation. Serum obtained from these mice before tumor challenge contained anti-anti-Id that failed to bind T-Ag. These data support the potential role of regulatory idiotopes in tumor immunity.

scholarly journals Phosphorylation of p53 in normal and simian virus 40-transformed NIH 3T3 cells

1988 ◽  
Vol 8 (1) ◽  
pp. 461-465
Author(s):  
D W Meek ◽  
W Eckhart
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

We observed six major tryptic phosphopeptides in p53 from simian virus 40-transformed and normal NIH 3T3 cells. Analyses of the phosphopeptides indicated that serines 37, 310 and/or 312, 389 and one or more of serines 7, 9, 12, 18, and 23 were phosphorylated. Phosphorylation of serines 310 and/or 312 was twofold higher in the simian virus 40-transformed cells as compared with that in normal NIH 3T3 cells.

Isolation of cellular genes differentially expressed in mouse NIH 3T3 cells and a simian virus 40-transformed derivative: growth-specific expression of VL30 genes

1985 ◽  
Vol 5 (10) ◽  
pp. 2590-2598
Author(s):  
K Singh ◽  
S Saragosti ◽  
M Botchan
Keyword(s):  
Cell Lines ◽  
Simian Virus 40 ◽  
Mouse Cell ◽  
Simian Virus ◽  
Differentially Expressed ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Transformed Cell ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

We constructed and screened a cDNA library made from simian virus 40 (SV40)-transformed NIH 3T3 cells, and we isolated cDNAs representing genes that are differentially expressed between the parental cell and its SV40-transformed derivative. We found only a small number of cDNAs representing such genes. Two isolated cDNA clones represented RNAs expressed at elevated levels in the transformed cell line in a manner relatively independent of growth conditions. The expression of two other cDNAs was growth specific because transformed cells and nonconfluent parental cells contained higher levels of the homologous RNAs than did confluent, contact-inhibited parental cells. Another cDNA was well expressed in confluent parental and confluent transformed cells, but not in nonconfluent cells. The expression of some of these cDNAs varied strikingly in different mouse cell lines. Thus the genotype or histories of different cell lines can also affect the expression of certain genes. Interestingly, the only cDNA isolated that was expressed exclusively in the transformed cell was from an SV40 message. We focused on a growth-specific cDNA which we show is derived from a mouse endogenous retrovirus-like family called VL30. We sequenced the 3' long terminal repeat (LTR) of this transcriptionally active VL30 gene. This LTR has good homology with other VL30 LTR sequences, but differences occur, particularly upstream of the VL30 promoter. We found that VL30 gene expression varied in different mouse cell lines such that C3H cell lines had very low levels of VL30 transcripts relative to NIH 3T3 cell lines. However, Southern analysis showed that both cell lines had about the same number of VL30 genes homologous to our probe and that the position of the majority of these genes was conserved. We discuss possible explanations for this difference in VL30 expression.

scholarly journals Phosphorylation of p53 in normal and simian virus 40-transformed NIH 3T3 cells.

1988 ◽  
Vol 8 (1) ◽  
pp. 461-465 ◽  
Author(s):  
D W Meek ◽  
W Eckhart
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

We observed six major tryptic phosphopeptides in p53 from simian virus 40-transformed and normal NIH 3T3 cells. Analyses of the phosphopeptides indicated that serines 37, 310 and/or 312, 389 and one or more of serines 7, 9, 12, 18, and 23 were phosphorylated. Phosphorylation of serines 310 and/or 312 was twofold higher in the simian virus 40-transformed cells as compared with that in normal NIH 3T3 cells.

Sign in / Sign up

Export Citation Format

Share Document