scholarly journals Monomer molecular weight of T antigen from simian virus 40-infected and transformed cells.

1976 ◽  
Vol 73 (7) ◽  
pp. 2254-2258 ◽  
Author(s):  
R. B. Carroll ◽  
A. E. Smith
Keyword(s):  
Molecular Weight ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells

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 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.

Relationship between T-antigen and tumor-specific transplantation antigen in simian virus 40-transformed cells.

1979 ◽  
Vol 29 (1) ◽  
pp. 69-75 ◽  
Author(s):  
C Chang ◽  
R G Martin ◽  
D M Livingston ◽  
S W Luborsky ◽  
C P Hu ◽  
...  
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Transplantation Antigen

The regulation of cellular transcription by Simian virus 40 large T-antigen

1985 ◽  
Vol 226 (1242) ◽  
pp. 15-23 ◽  
Keyword(s):  
Rna Polymerase Iii ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Productive Infection ◽  
Transformed Cells ◽  
Large T Antigen ◽  
Sv40 Large T Antigen ◽  
Cellular Genes ◽  
Cellular Transcription

The transforming protein of Simian virus 40 (SV40), large T-antigen, regulates transcription both positively and negatively during the productive infection cycle. We have isolated a number of cellular genes which are expressed at elevated levels in SV40-transformed cells and have used these to study the mechanism or mechanisms by which the viral transforming protein regulates cellular gene expression. Small RNAs homologous to the mouse B2 repetitive sequence family are found at higher levels in transformed cells than in normal cells and we have shown that pure large T-antigen stimulates transcription of such repeats by RNA polymerase III. A class I major histocompatibility complex (MHC) gene is also activated as a result of SV40 transformation and we have used DNA-mediated gene transfer to study how this gene is regulated by large T-antigen.

Reacquisition of a functional early region by a mouse transformant containing only defective simian virus 40 DNA

1984 ◽  
Vol 4 (4) ◽  
pp. 666-670
Author(s):  
S Chen ◽  
G Blanck ◽  
R Pollack
Keyword(s):  
Molecular Weight ◽  
Viral Protein ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
T Antigens ◽  
Viral Dna ◽  
Molecular Weights ◽  
Early Region ◽  
Mouse Cells

Viral DNA in simian virus 40-transformed mouse cells is capable of rearranging with passage. In this report, we show that such rearrangement can include an alteration in viral protein expression. SVT2, a simian virus 40-transformed mouse BALB/c 3T3 cell line, synthesizes only a super T antigen of molecular weight 100,000 without synthesizing the lytic-size large T or small t antigens with molecular weights of 94,000 and 17,000, respectively. Analyses of the integrated viral DNA revealed an early region of 4.4 kilobases instead of the lytic-size 2.7 kilobases. However, upon subcloning in either plastic or agarose or after being in culture for several passages, the appearance of lytic-size large T and small t antigens was detected. Concurrently, an early region of 2.7 kilobases, in addition to one of 4.4 kilobases, was observed.

Surface T-antigen expression in simian virus 40-transformed mouse cells: correlation with cell growth rate

1985 ◽  
Vol 5 (5) ◽  
pp. 1051-1057
Author(s):  
M Santos ◽  
J S Butel
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Growth Control ◽  
Simian Virus 40 ◽  
Antigen Expression ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Seeding Density ◽  
Cell Growth Rate

Cell growth control appears to be drastically altered as a consequence of transformation. Because the cell surface appears to have a role in modulating cell growth and simian virus 40 (SV40)-transformed cells express large T antigen (T-Ag) in the plasma membrane, we investigated whether surface T-Ag expression varies according to cell growth rate. Different growth states were obtained by various combinations of seeding density, serum concentration, and temperature, and cell cycle distributions were determined by flow microcytofluorometry. Actively dividing SV40-transformed mouse cell cultures were consistently found to express higher levels of surface T-Ag and T-Ag/p53 complex than cultures in which cells were mostly resting. In addition, the T-Ag/p53 complex disappeared from the surface of tsA7-transformed cells cultured under restrictive conditions known to induce complete growth arrest (39.5 degrees C), although the surface complex did not disappear from other tsA transformants able to keep cycling at 39.5 degrees C. These results suggest that surface SV40 T-Ag or surface T-Ag/p53 complex, or both, are involved in determining the growth characteristics of SV40-transformed cells.

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