Cellular mutation mediates T-antigen-positive revertant cells resistant to simian virus 40 transformation but not to retransformation by polyomavirus and adenovirus type 2

Bauer, Michael; Guhl, Eva; Graessmann, M.; Graessmann, A.

doi:10.1128/jvi.61.6.1821-1827.1987

Cited by 27 publications

(17 citation statements)

References 29 publications

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“…This is shown in Fig. 8, representing an analysis of the MDM2 content in normal rat F111 (lane 1) and REF52 (lane 2) fibroblasts, as well as in SV52 cells (lane 3), a derivative of REF52 cells (6). For comparison, the MDM2 content of Swiss 3T3 cells is shown in lane 4.…”

Section: Mdm2 Becomes Metabolically Stabilized During Sv40 Transformamentioning

confidence: 99%

“…The cells used in this study were normal Fisher rat fibroblasts REF52 (6) and F111 (25), SV40-transformed REF52 rat fibroblasts (SV52) (6), Swiss 3T3 (75) and SV40-transformed Swiss SV3T3 mouse fibroblasts, and an African green monkey kidney cell line (CV1) (36). All cells were grown at 37°C in Dulbecco modified Eagle medium (DMEM) supplemented with 10% fetal calf serum (FCS).…”

Section: Cells and Virus Infectionmentioning

confidence: 99%

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MDM2 is a target of simian virus 40 in cellular transformation and during lytic infection

Henning

Rohaly

Kolzau

et al. 1997

J Virol

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Phosphopeptide analyses of the simian virus 40 (SV40) large tumor antigen (LT) in SV40-transformed rat cells, as well as in SV40 lytically infected monkey cells, showed that gel-purified LT that was not complexed to p53 (free LT) and p53-complexed LT differed substantially in their phosphorylation patterns. Most significantly, p53-complexed LT contained phosphopeptides not found in free LT. We show that these additional phosphopeptides were derived from MDM2, a cellular antagonist of p53, which coprecipitated with the p53-LT complexes, probably in a trimeric LT-p53-MDM2 complex. MDM2 also quantitatively bound the free p53 in SV40-transformed cells. Free LT, in contrast, was not found in complex with MDM2, indicating a specific targeting of the MDM2 protein by SV40. This specificity is underscored by significantly different phosphorylation patterns of the MDM2 proteins in normal and SV40-transformed cells. Furthermore, the MDM2 protein, like p53, becomes metabolically stabilized in SV40-transformed cells. This suggests the possibility that the specific targeting of MDM2 by SV40 is aimed at preventing MDM2-directed proteasomal degradation of p53 in SV40-infected and -transformed cells, thereby leading to metabolic stabilization of p53 in these cells.

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Section: Mdm2 Becomes Metabolically Stabilized During Sv40 Transformamentioning

confidence: 99%

Section: Cells and Virus Infectionmentioning

confidence: 99%

MDM2 is a target of simian virus 40 in cellular transformation and during lytic infection

Henning

Rohaly

Kolzau

et al. 1997

J Virol

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“…Spodopteru frugiperda (Sf21) cells (kindly provided by S. Tija, KO1n) were grown as monolayer cultures in TCIOO medium supplemented with 10% fetal calf serum. Normal (F111) or SV40 LT-transformed rat fibroblasts SV52 (Bauer et al, 1987) and C8 (Kalderon and Smith, 1984) were used for comparison. Rat cells were grown as monolayers in Dulbecco's minimal essential medium supplemented with 5 % or 10% fetal calf serum.…”

Section: Cell Lines and Virusmentioning

confidence: 99%

Phosphorylation Studies on Rat p53 Using the Baculovirus Expression System

Fuchs

Hecker

Scheidtmann

1995

European Journal of Biochemistry

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To elucidate the role of phosphorylation of p53 we used the baculovims expression system to obtain high yields of protein eventually in distinct phosphorylation states. Initially, we obtained only marginal phosphorylation, despite high levels of expression. Two-dimensional phosphopeptide maps exhibited the same pattern as known from rat cells although some sites were underrepresented. Coexpression of simian virus 40 (SV40) large T antigen or cyclin-dependent kinases, cdc2 or cdk2, had only marginal effects on the phosphorylation state of p53. However, when we employed the phosphatase inhibitor okadaic acid, overall phosphorylation of p53 was drastically enhanced in a dose-dependent manner and resembled that of p53 from SV40-transformed rat cells. This hyperphosphorylation resulted in enhanced binding of a consensus oligonucleotide as revealed by electrophoretic mobility shift assays. To assess the role of individual phosphorylation sites, we generated a set of mutants at putative or identified sites. All mutants retained the ability to bind wild-type conformation-specific antibody Pab1620, to complex with SV40 large T antigen, and to bind to the consensus oligonucleotide. Moreover, most mutants exhibited enhanced DNA binding upon okadaic acid treatment, except for a mutant at the cdk site which failed to do so. These data show that: (a) insect cells contain all the protein kinases necessary for phosphorylation of a mammalian protein, p53 ; (b) in insect cells the ratio of kinase/phosphatase activities differs from that in mammalian cells so that underphosphorylation of recombinant proteins in this system may result from high phosphatase activities rather than saturation of kinases with recombinant substrate ; (c) the system can be manipulated to obtain subpopulations of recombinant protein in a desired phosphorylation state, and (d) phosphorylation may regulate the DNA-binding activity of p53.

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“…As can be seen in Figure 2, the parental cell line Ad5112-7C3Tl and the chromosome 3 MCH 429.8 did not significantly survive the selection. The (Bauer et al, 1987). Cells (loh) were seeded on a 9-cm dish and cultured in medium lacking both serum and methionine.…”

Section: Growth Properties In Vitromentioning

confidence: 99%

Human chromosome 11 suppresses the tumorigenicity of adenovirus transformed baby rat kidney cells: Involvement of the wilms' tumor 1 gene

Menke

Ham

Sonneveld

et al. 1995

Intl Journal of Cancer

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Human chromosome 11 was introduced into adenovirus-transformed baby rat kidney (BRK) cells by microcell-mediated chromosome transfer. The resulting microcell hybrids (MCHs) showed a reduced ability to form tumors upon s.c. injection into athymic mice. Further analysis, with the use of defined deletion chromosomes of 11p, indicated that the presence of region 11p13-p12 is necessary for the suppression of tumorigenicity. In contrast, the presence of region 11p15-14.1 appeared to increase the rate of tumor growth. Expression studies on the human Wilms' tumor I (WTI) and the insulin-like growth factor II (IGF-II) genes, which lie in regions 11p13 and 11p15, respectively, suggested the involvement of both genes in determining the degree of suppression of tumorigenicity. Finally, stable expression of a murine WTI protein in the adenovirus-transformed cells resulted in almost complete suppression of tumorigenicity, establishing the WTI protein as a tumor suppressor in this cell system.

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Cellular mutation mediates T-antigen-positive revertant cells resistant to simian virus 40 transformation but not to retransformation by polyomavirus and adenovirus type 2

Cited by 27 publications

References 29 publications

MDM2 is a target of simian virus 40 in cellular transformation and during lytic infection

MDM2 is a target of simian virus 40 in cellular transformation and during lytic infection

Phosphorylation Studies on Rat p53 Using the Baculovirus Expression System

Human chromosome 11 suppresses the tumorigenicity of adenovirus transformed baby rat kidney cells: Involvement of the wilms' tumor 1 gene

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