Separation of simian virus 40 large-T-antigen-transforming and origin-binding functions from the ability to block differentiation

1988 ◽  
Vol 8 (3) ◽  
pp. 1380-1384 ◽  
Author(s):  
V Cherington ◽  
M Brown ◽  
E Paucha ◽  
J St Louis ◽  
B M Spiegelman ◽  
...  
Keyword(s):  
Dehydrogenase Activity ◽  
Adipocyte Differentiation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Lipid Binding ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Glycerophosphate Dehydrogenase ◽  
Triglyceride Accumulation

Wild-type simian virus 40 large T antigen is very effective at blocking adipocyte differentiation in 3T3-F442A cells as assayed by triglyceride accumulation, induction of glycerophosphate dehydrogenase activity, and expression of mRNAs for glycerophosphate dehydrogenase, the adipocyte serine protease adipsin, and the putative lipid-binding protein adipocyte P2. Point mutants defective for either origin-specific DNA binding or transformation blocked differentiation as completely as wild type.

scholarly journals Separation of simian virus 40 large-T-antigen-transforming and origin-binding functions from the ability to block differentiation.

1988 ◽  
Vol 8 (3) ◽  
pp. 1380-1384 ◽  
Author(s):  
V Cherington ◽  
M Brown ◽  
E Paucha ◽  
J St Louis ◽  
B M Spiegelman ◽  
...  
Keyword(s):  
Dehydrogenase Activity ◽  
Adipocyte Differentiation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Lipid Binding ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Glycerophosphate Dehydrogenase ◽  
Triglyceride Accumulation

Wild-type simian virus 40 large T antigen is very effective at blocking adipocyte differentiation in 3T3-F442A cells as assayed by triglyceride accumulation, induction of glycerophosphate dehydrogenase activity, and expression of mRNAs for glycerophosphate dehydrogenase, the adipocyte serine protease adipsin, and the putative lipid-binding protein adipocyte P2. Point mutants defective for either origin-specific DNA binding or transformation blocked differentiation as completely as wild type.

scholarly journals Excess wild-type p53 blocks initiation and maintenance of simian virus 40 transformation.

1991 ◽  
Vol 11 (7) ◽  
pp. 3472-3483 ◽  
Author(s):  
K Fukasawa ◽  
G Sakoulas ◽  
R E Pollack ◽  
S Chen
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Sv40 Large T Antigen ◽  
Sv40 Transformation ◽  
Mouse Cells ◽  
Wild Type P53

Wild-type (wt) murine p53 has been tested for its ability to block and reverse the transforming effects of simian virus 40 (SV40) large T antigen. Established and precrisis mouse cells overexpressing exogenously introduced wt p53 became resistant to SV40 transformation. The introduction of excess wt p53 into SV40-transformed precrisis cells reverted their transformed phenotype. However, the phenotype of SV40-transformed established cells was not reverted by excess wt p53. We conclude that an antioncogenic action of wt p53 is exerted during SV40 transformation and that in precrisis cells, the antitransforming action of wt p53 can be exerted both at initiation and during the maintenance of transformation.

Less than 40% of the simian virus 40 large T-antigen-coding sequence is required for transformation

1984 ◽  
Vol 4 (8) ◽  
pp. 1661-1663
Author(s):  
L Sompayrac ◽  
K J Danna
Keyword(s):  
Dna Sequences ◽  
Deletion Mutant ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Large Deletion ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Coding Sequence ◽  
Mouse Cells

F8dl is a simian virus 40 early-region deletion mutant that lacks the simian virus 40 DNA sequences between 0.168 and 0.424 map units. Despite this large deletion, cloned F8dl DNA transforms Fisher rat F111 cells and BALB/3T3 clone A31 mouse cells as efficiently as does cloned simian virus 40 wild-type DNA. These results indicate that less than 40% of the large T-antigen-coding sequence is required for efficient transformation.

Excess wild-type p53 blocks initiation and maintenance of simian virus 40 transformation

1991 ◽  
Vol 11 (7) ◽  
pp. 3472-3483
Author(s):  
K Fukasawa ◽  
G Sakoulas ◽  
R E Pollack ◽  
S Chen
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Sv40 Large T Antigen ◽  
Sv40 Transformation ◽  
Mouse Cells ◽  
Wild Type P53

Wild-type (wt) murine p53 has been tested for its ability to block and reverse the transforming effects of simian virus 40 (SV40) large T antigen. Established and precrisis mouse cells overexpressing exogenously introduced wt p53 became resistant to SV40 transformation. The introduction of excess wt p53 into SV40-transformed precrisis cells reverted their transformed phenotype. However, the phenotype of SV40-transformed established cells was not reverted by excess wt p53. We conclude that an antioncogenic action of wt p53 is exerted during SV40 transformation and that in precrisis cells, the antitransforming action of wt p53 can be exerted both at initiation and during the maintenance of transformation.

scholarly journals Signal-dependent translocation of simian virus 40 large-T antigen into rat liver nuclei in a cell-free system.

1987 ◽  
Vol 7 (12) ◽  
pp. 4255-4265 ◽  
Author(s):  
W Markland ◽  
A E Smith ◽  
B L Roberts
Keyword(s):  
Rat Liver ◽  
Nuclear Translocation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Rat Liver Nuclei ◽  
Liver Nuclei

An in vitro nuclear translocation system is described in which isolated rat liver nuclei were incubated in a defined buffered medium containing radiolabeled or fluorescently labeled exogenous proteins. The nuclei were rapidly recovered, extracted, and analyzed for the presence of associated radiolabeled or fluorescently labeled proteins. The isolated nuclei exhibited the same specificity for protein uptake as seen previously in vivo, accumulating simian virus 40 wild-type large-T antigen and p53 while excluding a cytoplasmic variant of large-T antigen (d10) and bovine serum albumin. The rapid nuclear accumulation of wild-type large-T antigen was shown to be selective and dependent upon the recognition of a wild-type nuclear location signal, ATP and temperature dependent, and unidirectional. Taken together, the data suggest that in our in vitro system the nuclear translocation of wild-type large-T antigen exhibits some of the characteristics of an active transport process.

Definition of the minimal simian virus 40 large T antigen- and adenovirus E1A-binding domain in the retinoblastoma gene product

1990 ◽  
Vol 10 (7) ◽  
pp. 3761-3769
Author(s):  
W G Kaelin ◽  
M E Ewen ◽  
D M Livingston
Keyword(s):  
Gene Product ◽  
Structural Information ◽  
Susceptibility Gene ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Adenovirus E1a

It has previously been demonstrated that the simian virus 40 large T antigen and adenovirus E1A proteins can form complexes with the retinoblastoma susceptibility gene product (RB). We studied the ability of these proteins to bind to mutant RB proteins in vitro. A region of RB spanning residues 379 to 792 was found to be both necessary and sufficient for binding to T or E1A. Furthermore, this region of RB contains sufficient structural information to mimic wild-type RB in its ability to distinguish between wild-type T and the transformation-defective T mutant K1. The results of competition experiments with peptide analogs of the RB-binding sequence in T suggest that this region of RB makes direct contact with a short colinear region of T, i.e., residues 102 to 115, previously implicated in both transformation and RB binding.

scholarly journals Less than 40% of the simian virus 40 large T-antigen-coding sequence is required for transformation.

1984 ◽  
Vol 4 (8) ◽  
pp. 1661-1663 ◽  
Author(s):  
L Sompayrac ◽  
K J Danna
Keyword(s):  
Dna Sequences ◽  
Deletion Mutant ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Large Deletion ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
Coding Sequence ◽  
Mouse Cells

F8dl is a simian virus 40 early-region deletion mutant that lacks the simian virus 40 DNA sequences between 0.168 and 0.424 map units. Despite this large deletion, cloned F8dl DNA transforms Fisher rat F111 cells and BALB/3T3 clone A31 mouse cells as efficiently as does cloned simian virus 40 wild-type DNA. These results indicate that less than 40% of the large T-antigen-coding sequence is required for efficient transformation.

scholarly journals Wild-Type p53 Enhances Efficiency of Simian Virus 40 Large-T-Antigen-Induced Cellular Transformation

2009 ◽  
Vol 83 (19) ◽  
pp. 10106-10118 ◽  
Author(s):  
Andrea Hermannstädter ◽  
Christine Ziegler ◽  
Marion Kühl ◽  
Wolfgang Deppert ◽  
Genrich V. Tolstonog
Keyword(s):  
Transformation Efficiency ◽  
Simian Virus 40 ◽  
Transcriptional Regulators ◽  
Cellular Transformation ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Wild Type ◽  
3T3 Cells ◽  
Sv40 Transformation

ABSTRACT Abortive infection of BALB/c mouse embryo fibroblasts differing in p53 gene status (p53+/+ versus p53−/ −) with simian virus 40 (SV40) revealed a quantitatively and qualitatively decreased transformation efficiency in p53−/− cells compared to p53+/+ cells, suggesting a supportive effect of wild-type (wt) p53 in the SV40 transformation process. SV40 transformation efficiency also was low in immortalized p53−/− BALB/c 10-1 cells but could be restored to approximately the level in immortalized p53+/+ BALB/c 3T3 cells by reconstituting wt p53, but not mutant p53 (mutp53), expression. Stable expression of large T antigen (LT) in p53+/+ 3T3 cells resulted in full transformation, while LT expression in p53−/− 10-1 cells could not promote growth in suspension or in soft agar to a significant extent. The helper effect of wt p53 is mediated by its cooperation with LT and resides in the p53 N terminus, as an N-terminally truncated p53 (ΔNp53) could not rescue the p53-null phenotype. The p53 N terminus serves as a scaffold for recruiting transcriptional regulators like p300/CBP and Mdm2 into the LT-p53 complex. Consequently, LT affected global and specific gene expression in p53+/+ cells significantly more than in p53−/− cells. Our data suggest that recruitment of transcriptional regulators into the LT-p53 complex may help to modify cellular gene expression in response to the needs of cellular transformation.

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