Cell cycle dependent transcription of SV40 [Simian virus 40] DNA in SV40-transformed cells

Biochemistry ◽  
1974 ◽  
Vol 13 (20) ◽  
pp. 4122-4126 ◽  
Author(s):  
Peter Swetly ◽  
Yasushi Watanabe
Keyword(s):  
Cell Cycle ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformed Cells ◽  
Cycle Dependent

scholarly journals Hyperphosphorylation of the retinoblastoma gene product is determined by domains outside the simian virus 40 large-T-antigen-binding regions.

1990 ◽  
Vol 10 (12) ◽  
pp. 6586-6595 ◽  
Author(s):  
P A Hamel ◽  
B L Cohen ◽  
L M Sorce ◽  
B L Gallie ◽  
R A Phillips
Keyword(s):  
Cell Cycle ◽  
Complex Formation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Phosphorylation Sites ◽  
Dependent Manner ◽  
Large T Antigen ◽  
T Complex ◽  
Cycle Dependent

With the murine retinoblastoma (RB) cDNA, a series of RB mutants were expressed in COS-1 cells and the pRB products were assessed for their ability (i) to bind to large T antigen (large T), (ii) to become modified by phosphorylation, and (iii) to localize in the nucleus. All point mutations and deletions introduced into regions previously defined as contributing to binding to large T abolished pRB-large T complex formation and prevented hyperphosphorylation of the RB protein. In contrast, a series of deletions 5' to these sites did not interfere with binding to large T. While some of the 5' deletion mutants were clearly phosphorylated in a cell cycle-dependent manner, one, delta Pvu, failed to be phosphorylated depsite binding to large T. pRB with mutations created at three putative p34cdc2 phosphorylation sites in the N-terminal region behaved similarly to wild-type pRB, whereas the construct delta P5-6-7-8, mutated at four serine residues C terminal to the large T-binding site, failed to become hyperphosphorylated despite retaining the ability to bind large T. All of the mutants described were also found to localize in the nucleus. These results demonstrate that the domains in pRB responsible for binding to large T are distinct from those recognized by the relevant pRB-specific kinase(s) and/or those which contain cell cycle-dependent phosphorylation sites. Furthermore, these data are consistent with a model in which cell cycle-dependent phosphorylation of pRB requires complex formation with other cellular proteins.

scholarly journals Enhancement of DNA-mediated gene transfer by high-Mr carrier DNA in synchronized CV-1 cells

1985 ◽  
Vol 225 (2) ◽  
pp. 529-533 ◽  
Author(s):  
A J Strain ◽  
W A H Wallace ◽  
A H Wyllie
Keyword(s):  
Cell Cycle ◽  
Gene Transfer ◽  
Transfection Efficiency ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
S Phase ◽  
Sv40 Virus ◽  
G2 Phase ◽  
Cycle Dependent ◽  
Sv40 Dna

Synchronized CV-1 cells were transfected with SV40 (simian virus 40) DNA-calcium phosphate co-precipitates. In the presence of carrier DNA, the transfection efficiency of SV40 DNA was decreased 5-fold in S-phase cells and was increased 4-fold in preparations of mitotically enriched cells as compared with asynchronous controls. No difference was observed when carrier DNA was omitted, when cells had progressed through S-phase and into G2-phase, or when the infectivity of cells to intact SV40 virus was tested. These results highlight the importance of cell-cycle-dependent factors on DNA-mediated gene transfer.

Cell cycle-dependent expression of early viral genes in one group of simian virus 40-transformed rat cells.

1984 ◽  
Vol 3 (11) ◽  
pp. 2587-2591 ◽  
Author(s):  
J. Imbert ◽  
J.J. Lawrence ◽  
F. Coulier ◽  
E. Jeunet ◽  
V. Billotey ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Viral Genes ◽  
Cycle Dependent

scholarly journals Permanent expression of p53 in FR 3T3 rat cells but cell cycle-dependent association with large-T antigen in simian virus 40 transformants.

1985 ◽  
Vol 4 (13A) ◽  
pp. 3413-3418 ◽  
Author(s):  
F. Coulier ◽  
J. Imbert ◽  
J. Albert ◽  
E. Jeunet ◽  
J.J. Lawrence ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large T Antigen ◽  
Cycle Dependent

scholarly journals Human fibroblast commitment to a senescence-like state in response to histone deacetylase inhibitors is cell cycle dependent.

1996 ◽  
Vol 16 (9) ◽  
pp. 5210-5218 ◽  
Author(s):  
V V Ogryzko ◽  
T H Hirai ◽  
V R Russanova ◽  
D A Barbie ◽  
B H Howard
Keyword(s):  
Cell Cycle ◽  
Histone Deacetylase ◽  
Histone Deacetylase Inhibitors ◽  
Replicative Senescence ◽  
Trichostatin A ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Human Diploid Fibroblasts ◽  
Cycle Dependent

Human diploid fibroblasts (HDF) complete a limited number of cell divisions before entering a growth arrest state that is termed replicative senescence. Two histone deacetylase inhibitors, sodium butyrate and trichostatin A, dramatically reduce the HDF proliferative life span in a manner that is dependent on one or more cell doublings in the presence of these agents. Cells arrested and subsequently released from histone deacetylase inhibitors display markers of senescence and exhibit a persistent G1 block but remain competent to initiate a round of DNA synthesis in response to simian virus 40 T antigen. Average telomere length in prematurely arrested cells is greater than in senescent cells, reflecting a lower number of population doublings completed by the former. Taken together, these results support the view that one component of HDF senescence mimics a cell cycle-dependent drift in differentiation state and that propagation of HDF in histone deacetylase inhibitors accentuates this component.

scholarly journals Phosphorylation of Simian Virus 40 T Antigen on Thr 124 Selectively Promotes Double-Hexamer Formation on Subfragments of the Viral Core Origin

2000 ◽  
Vol 74 (18) ◽  
pp. 8601-8613 ◽  
Author(s):  
Brett A. Barbaro ◽  
K. R. Sreekumar ◽  
Danielle R. Winters ◽  
Andrea E. Prack ◽  
Peter A. Bullock
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Control ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Large Tumor ◽  
Sv40 Origin ◽  
Cycle Dependent ◽  
Sv40 Dna

ABSTRACT Cell cycle-dependent phosphorylation of simian virus 40 (SV40) large tumor antigen (T-ag) on threonine 124 is essential for the initiation of viral DNA replication. A T-ag molecule containing a Thr→Ala substitution at this position (T124A) was previously shown to bind to the SV40 core origin but to be defective in DNA unwinding and initiation of DNA replication. However, exactly what step in the initiation process is defective as a result of the T124A mutation has not been established. Therefore, to better understand the control of SV40 replication, we have reinvestigated the assembly of T124A molecules on the SV40 origin. Herein it is demonstrated that hexamer formation is unaffected by the phosphorylation state of Thr 124. In contrast, T124A molecules are defective in double-hexamer assembly on subfragments of the core origin containing single assembly units. We also report that T124A molecules are inhibitors of T-ag double hexamer formation. These and related studies indicate that phosphorylation of T-ag on Thr 124 is a necessary step for completing the assembly of functional double hexamers on the SV40 origin. The implications of these studies for the cell cycle control of SV40 DNA replication are discussed.

Hyperphosphorylation of the retinoblastoma gene product is determined by domains outside the simian virus 40 large-T-antigen-binding regions

1990 ◽  
Vol 10 (12) ◽  
pp. 6586-6595
Author(s):  
P A Hamel ◽  
B L Cohen ◽  
L M Sorce ◽  
B L Gallie ◽  
R A Phillips
Keyword(s):  
Cell Cycle ◽  
Complex Formation ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Phosphorylation Sites ◽  
Dependent Manner ◽  
Large T Antigen ◽  
T Complex ◽  
Cycle Dependent

With the murine retinoblastoma (RB) cDNA, a series of RB mutants were expressed in COS-1 cells and the pRB products were assessed for their ability (i) to bind to large T antigen (large T), (ii) to become modified by phosphorylation, and (iii) to localize in the nucleus. All point mutations and deletions introduced into regions previously defined as contributing to binding to large T abolished pRB-large T complex formation and prevented hyperphosphorylation of the RB protein. In contrast, a series of deletions 5' to these sites did not interfere with binding to large T. While some of the 5' deletion mutants were clearly phosphorylated in a cell cycle-dependent manner, one, delta Pvu, failed to be phosphorylated depsite binding to large T. pRB with mutations created at three putative p34cdc2 phosphorylation sites in the N-terminal region behaved similarly to wild-type pRB, whereas the construct delta P5-6-7-8, mutated at four serine residues C terminal to the large T-binding site, failed to become hyperphosphorylated despite retaining the ability to bind large T. All of the mutants described were also found to localize in the nucleus. These results demonstrate that the domains in pRB responsible for binding to large T are distinct from those recognized by the relevant pRB-specific kinase(s) and/or those which contain cell cycle-dependent phosphorylation sites. Furthermore, these data are consistent with a model in which cell cycle-dependent phosphorylation of pRB requires complex formation with other cellular proteins.

Relationship Among Tau Antigens Isolated from Various Lines of Simian Virus 40-Transformed Cells

1980 ◽  
Vol 34 (3) ◽  
pp. 650-657 ◽  
Author(s):  
Daniel T. Simmons ◽  
Malcolm A. Martin ◽  
Peter T. Mora ◽  
Chungming Chang
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformed Cells

E1A induces phosphorylation of the retinoblastoma protein independently of direct physical association between the E1A and retinoblastoma products

1991 ◽  
Vol 11 (8) ◽  
pp. 4253-4265
Author(s):  
H G Wang ◽  
G Draetta ◽  
E Moran
Keyword(s):  
Cell Cycle ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Binding Activity ◽  
T Antigen ◽  
Physical Interaction ◽  
Resting Cells ◽  
Wild Type ◽  
Quiescent Cells ◽  
Kinase Expression

We have studied the initial effects of adenovirus E1A expression on the retinoblastoma (RB) gene product in normal quiescent cells. Although binding of the E1A products to pRB could, in theory, make pRB phosphorylation unnecessary for cell cycle progression, we have found that the 12S wild-type E1A product is capable of inducing phosphorylation of pRB in normal quiescent cells. The induction of pRB phosphorylation correlates with E1A-mediated induction of p34cdc2 expression and kinase activity, consistent with the possibility that p34cdc2 is a pRB kinase. Expression of simian virus 40 T antigen induces similar effects. Induction of pRB phosphorylation is independent of the pRB binding activity of the E1A products; E1A domain 2 mutants do not bind detectable levels of pRB but remain competent to induce pRB phosphorylation and to activate cdc2 protein kinase expression and activity. Although the kinetics of induction are slower, domain 2 mutants induce wild-type levels of pRB phosphorylation and host cell DNA synthesis and yet fail to induce cell proliferation. These results imply that direct physical interaction between the RB and E1A products does not play a required role in the early stages of E1A-mediated cell cycle induction and that pRB phosphorylation is not, of itself, sufficient to allow quiescent cells to divide. These results suggest that the E1A products do not need to bind pRB in order to stimulate resting cells to enter the cell cycle. Indeed, a more important role of the RB binding activity of the E1A products may be to prevent dividing cells from returning to G0.

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