scholarly journals THE INDUCTION OF CELLULAR DNA SYNTHESIS BY SIMIAN VIRUS 40 IN CONTACT-INHIBITED AND IN X-IRRADIATED CELLS

1966 ◽  
Vol 56 (3) ◽  
pp. 918-925 ◽  
Author(s):  
D. Gershon ◽  
L. Sachs ◽  
E. Winocour
Keyword(s):  
Dna Synthesis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Cellular 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 Induction of cellular DNA synthesis by a simian virus 40 mutant defective in nuclear transport of T antigen.

1985 ◽  
Vol 5 (6) ◽  
pp. 1531-1533 ◽  
Author(s):  
R E Lanford ◽  
J K Hyland ◽  
R Baserga ◽  
J S Butel
Keyword(s):  
Dna Synthesis ◽  
Limit Of Detection ◽  
Nuclear Transport ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Quiescent Cells ◽  
Cellular Dna

The simian virus 40 (SV40) (cT)-3 mutant [SV40(cT)-3], which is defective in nuclear transport of T antigen, was utilized to determine whether cellular DNA synthesis can be stimulated by SV40 in the absence of detectable nuclear T antigen. Cellular DNA synthesis was examined in the temperature-sensitive cell cycle mutants, BHK ts13 and BHK tsAF8, after microinjection of quiescent cells with plasmid DNA containing cloned copies of wild-type SV40 or SV40(cT)-3. The efficiency of induction of cellular DNA synthesis was identical for both wild-type SV40 and SV40(cT)-3 in both cell lines. The results suggest that cell surface-associated T antigen, either alone or possibly in combination with minimal amounts of nuclear T antigen below our limit of detection, is able to stimulate cellular DNA synthesis.

scholarly journals Induction of Cellular DNA Synthesis by the Nondefective Adenovirus 2-Simian Virus 40 Hybrid Viruses

1973 ◽  
Vol 12 (4) ◽  
pp. 940-943 ◽  
Author(s):  
Lowell E. Schnipper ◽  
Andrew M. Lewis ◽  
Arthur S. Levine
Keyword(s):  
Dna Synthesis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Cellular Dna

scholarly journals Genetic evidence that acute morphologic transformation, induction of cellular DNA synthesis, and focus formation are mediated by a single activity of the bovine papillomavirus E5 protein.

1989 ◽  
Vol 9 (12) ◽  
pp. 5563-5572 ◽  
Author(s):  
J Settleman ◽  
A Fazeli ◽  
J Malicki ◽  
B H Horwitz ◽  
D DiMaio
Keyword(s):  
Dna Synthesis ◽  
Mutational Analysis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Serum Starvation ◽  
Bovine Papillomavirus ◽  
Focus Formation ◽  
E5 Protein ◽  
Cellular Dna

The bovine papillomavirus (BPV) type 1 E5 gene encodes a 44-amino-acid protein that can stably transform cultured rodent cells when expressed in the absence of all other viral genes. We have previously constructed a BPV-simian virus 40 recombinant virus (Pava-1) which efficiently expresses the BPV type 1 E5 gene in infected cells (J. Settleman and D. DiMaio, Proc. Natl. Acad. Sci. USA 85:9007-9011, 1988). Within 48 h of Pava-1 infection, the vast majority of mouse C127 cells underwent a dramatic morphologic transformation which was accompanied by cell proliferation. Infection of C127 cells made quiescent by contact inhibition and serum starvation caused a great induction of cellular DNA synthesis. These morphologic and mitogenic responses were proportional to the virus multiplicity of infection. Mutational analysis indicated that the E5 gene is both necessary and sufficient for these activities. Analysis of a variety of E5 missense mutants revealed a strong correlation between their phenotypes in the acute transformation assays following infection and in the stable focus-forming assay following transfection. Most of the defective mutants expressed normal levels of E5 protein following infection, indicating that their defective phenotypes are not due to the synthesis of an unstable protein. The failure to genetically resolve these E5 activities suggests that the ability of the E5 protein to cause acute morphologic transformation and reentry into the cell cycle may be intimately related to its ability to cause stable cell transformation and that these functions are probably mediated by a single biochemical activity of the E5 protein.

Induction of cellular DNA synthesis by a simian virus 40 mutant defective in nuclear transport of T antigen

1985 ◽  
Vol 5 (6) ◽  
pp. 1531-1533
Author(s):  
R E Lanford ◽  
J K Hyland ◽  
R Baserga ◽  
J S Butel
Keyword(s):  
Dna Synthesis ◽  
Limit Of Detection ◽  
Nuclear Transport ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Quiescent Cells ◽  
Cellular Dna

The simian virus 40 (SV40) (cT)-3 mutant [SV40(cT)-3], which is defective in nuclear transport of T antigen, was utilized to determine whether cellular DNA synthesis can be stimulated by SV40 in the absence of detectable nuclear T antigen. Cellular DNA synthesis was examined in the temperature-sensitive cell cycle mutants, BHK ts13 and BHK tsAF8, after microinjection of quiescent cells with plasmid DNA containing cloned copies of wild-type SV40 or SV40(cT)-3. The efficiency of induction of cellular DNA synthesis was identical for both wild-type SV40 and SV40(cT)-3 in both cell lines. The results suggest that cell surface-associated T antigen, either alone or possibly in combination with minimal amounts of nuclear T antigen below our limit of detection, is able to stimulate cellular DNA synthesis.

Mutational analysis of simian virus 40 T antigen: stimulation of cellular DNA synthesis and activation of rRNA genes by mutants with deletions in the T-antigen gene

1983 ◽  
Vol 3 (2) ◽  
pp. 214-219
Author(s):  
K J Soprano ◽  
N Galanti ◽  
G J Jonak ◽  
S McKercher ◽  
J M Pipas ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Mutational Analysis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Rrna Genes ◽  
Hybrid Cells ◽  
The Common ◽  
Cellular Dna ◽  
Stimulation Of

The biological activity of several deletion mutants of simian virus 40, cloned in pBR322, was determined. Three functions of the simian virus 40 A gene were studied: (i) the ability to express T antigen; (ii) the ability to induce cell DNA replication; and (iii) the ability to reactivate silent rRNA genes in hybrid cells. Recombinant plasmid DNA was introduced into cells by manual microinjection or by transfection. The results (together with previous reports) indicate that the critical sequences for these three functions are located separately on the simian virus 40 A gene, as follows: (i) the sequences necessary for the detection of the common antigenic determinant of T antigen extend from nucleotide 4147 to nucleotide 4001 (map units 0.45 to 0.42); (ii) the sequences critical for the stimulation of cell DNA synthesis extend from nucleotide 4327 to nucleotide 4001 (map units 0.49 to 0.42); and (iii) those critical for the reactivation of rRNA genes extend approximately from nucleotide 3827 to nucleotide 3526 (map units 0.39 to 0.33).

scholarly journals 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.

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