scholarly journals Inducible and coupled expression of the polyomavirus middle T antigen and Cre recombinase in transgenic mice: an in vivo model for synthetic viability in mammary tumour progression

2014 ◽  
Vol 16 (1) ◽  
Author(s):  
Trisha Rao ◽  
Jill J Ranger ◽  
Harvey W Smith ◽  
Sonya H Lam ◽  
Lewis Chodosh ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Tumour Progression ◽  
Cre Recombinase ◽  
T Antigen ◽  
Mammary Tumour ◽  
In Vivo Model ◽  
Polyomavirus Middle T Antigen ◽  
Middle T Antigen

scholarly journals Induction of mammary tumors by expression of polyomavirus middle T oncogene: a transgenic mouse model for metastatic disease.

1992 ◽  
Vol 12 (3) ◽  
pp. 954-961 ◽  
Author(s):  
C T Guy ◽  
R D Cardiff ◽  
W J Muller
Keyword(s):  
Transgenic Mice ◽  
Transcriptional Control ◽  
Mammary Epithelium ◽  
Metastatic Potential ◽  
T Antigen ◽  
Specific Expression ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Polyomavirus Middle T Antigen ◽  
Middle T Antigen

The effect of mammary gland-specific expression of the polyomavirus middle T antigen was examined by establishing lines of transgenic mice that carry the middle T oncogene under the transcriptional control of the mouse mammary tumor virus promoter/enhancer. By contrast to most transgenic strains carrying activated oncogenes, expression of polyomavirus middle T antigen resulted in the widespread transformation of the mammary epithelium and the rapid production of multifocal mammary adenocarcinomas. Interestingly, the majority of the tumor-bearing transgenic mice developed secondary metastatic tumors in the lung. Taken together, these results suggest that middle T antigen acts as a potent oncogene in the mammary epithelium and that cells that express it possess an enhanced metastatic potential.

scholarly journals Retrovirus shuttle vector for study of kinase activities of pp60c-src synthesized in vitro and overproduced in vivo.

1986 ◽  
Vol 6 (6) ◽  
pp. 2033-2040 ◽  
Author(s):  
H Piwnica-Worms ◽  
D R Kaplan ◽  
M Whitman ◽  
T M Roberts
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Shuttle Vector ◽  
T Antigen ◽  
Protein Kinase Activity ◽  
Polyomavirus Middle T Antigen ◽  
Nih 3T3 ◽  
Middle T Antigen

We have constructed a recombinant murine retrovirus which efficiently transduces avian pp60c-src into murine cells and which is easily rescued from infected cells in plasmid form. To characterize the virus, several randomly selected NIH 3T3 lines were isolated after infection with recombinant retroviral stocks. All lines overproduced avian pp60c-src and appeared morphologically normal. Immunoprecipitates made from these lines with antisera specific for pp60c-src were tested for their kinase activities in vitro. We find that both autokinase and enolase kinase activities increase proportionately with the level of pp60c-src in the immunoprecipitates. To further test the authenticity of the pp60c-src encoded by the retroviral vector, these analyses were repeated in the presence of polyomavirus middle T antigen. Avian pp60c-src was activated as a protein kinase, indicating that the virally encoded pp60c-src interacts normally with middle T antigen. Interestingly, by increasing the intracellular levels of pp60c-src 15-fold over normal endogenous levels, we were unable to obtain a proportionate increase in the amount of middle-T-antigen-pp60c-src complex. Finally, using the shuttle features designed into the vector, we have isolated the first fully processed cDNA encoding functional avian pp60c-src X pp60c-src synthesized in vitro with this cDNA had intrinsic protein kinase activity and no detectable phosphatidylinositol kinase activity.

Induction of mammary tumors by expression of polyomavirus middle T oncogene: a transgenic mouse model for metastatic disease

1992 ◽  
Vol 12 (3) ◽  
pp. 954-961
Author(s):  
C T Guy ◽  
R D Cardiff ◽  
W J Muller
Keyword(s):  
Transgenic Mice ◽  
Transcriptional Control ◽  
Mammary Epithelium ◽  
Metastatic Potential ◽  
T Antigen ◽  
Specific Expression ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
Polyomavirus Middle T Antigen ◽  
Middle T Antigen

The effect of mammary gland-specific expression of the polyomavirus middle T antigen was examined by establishing lines of transgenic mice that carry the middle T oncogene under the transcriptional control of the mouse mammary tumor virus promoter/enhancer. By contrast to most transgenic strains carrying activated oncogenes, expression of polyomavirus middle T antigen resulted in the widespread transformation of the mammary epithelium and the rapid production of multifocal mammary adenocarcinomas. Interestingly, the majority of the tumor-bearing transgenic mice developed secondary metastatic tumors in the lung. Taken together, these results suggest that middle T antigen acts as a potent oncogene in the mammary epithelium and that cells that express it possess an enhanced metastatic potential.

scholarly journals Activation of Akt (Protein Kinase B) in Mammary Epithelium Provides a Critical Cell Survival Signal Required for Tumor Progression

2001 ◽  
Vol 21 (6) ◽  
pp. 2203-2212 ◽  
Author(s):  
John Hutchinson ◽  
Jing Jin ◽  
Robert D. Cardiff ◽  
Jim R. Woodgett ◽  
William J. Muller
Keyword(s):  
Mammary Gland ◽  
Transgenic Mice ◽  
Tumor Progression ◽  
Cell Survival ◽  
Mammary Epithelium ◽  
T Antigen ◽  
Survival Signal ◽  
Polyomavirus Middle T Antigen ◽  
Middle T Antigen ◽  
Phosphatidylinositol 3

ABSTRACT Activation of Akt by the phosphatidylinositol 3′-OH kinase (PI3K) results in the inhibition of proapoptotic signals and the promotion of survival signals (L. P. Kane et al., Curr. Biol. 9:601–604, 1999; G. J. Kops et al., Nature 398:630–634, 1999). Evidence supporting the importance of the PI3K/Akt signaling pathway in tumorigenesis stems from experiments with transgenic mice bearing polyomavirus middle T antigen under the control of the mouse mammary tumor virus long terminal repeat promoter. Mammary epithelium-specific expression of polyomavirus middle T antigen results in the rapid development of multifocal metastatic mammary tumors, whereas transgenic mice expressing a mutant middle T antigen decoupled from the phosphatidylinositol 3′-OH kinase (MTY315/322F) develop extensive mammary gland hyperplasias that are highly apoptotic. To directly assess the role of Akt in mammary epithelial development and tumorigenesis, we generated transgenic mice expressing constitutively active Akt (HAPKB308D473D or Akt-DD). Although expression of Akt-DD interferes with normal mammary gland involution, tumors were not observed in these strains. However, coexpression of Akt-DD with MTY315/322F resulted in a dramatic acceleration of mammary tumorigenesis correlated with reduced apoptotic cell death. Furthermore, coexpression of Akt-DD with MTY315/322F resulted in phosphorylation of the FKHR forkhead transcription factor and translational upregulation of cyclin D1 levels. Importantly, we did not observe an associated restoration of wild-type metastasis levels in the bitransgenic strain. Taken together these observations indicate that activation of Akt can contribute to tumor progression by providing an important cell survival signal but does not promote metastatic progression.

Retrovirus shuttle vector for study of kinase activities of pp60c-src synthesized in vitro and overproduced in vivo

1986 ◽  
Vol 6 (6) ◽  
pp. 2033-2040
Author(s):  
H Piwnica-Worms ◽  
D R Kaplan ◽  
M Whitman ◽  
T M Roberts
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Shuttle Vector ◽  
T Antigen ◽  
Protein Kinase Activity ◽  
Polyomavirus Middle T Antigen ◽  
Nih 3T3 ◽  
Middle T Antigen

We have constructed a recombinant murine retrovirus which efficiently transduces avian pp60c-src into murine cells and which is easily rescued from infected cells in plasmid form. To characterize the virus, several randomly selected NIH 3T3 lines were isolated after infection with recombinant retroviral stocks. All lines overproduced avian pp60c-src and appeared morphologically normal. Immunoprecipitates made from these lines with antisera specific for pp60c-src were tested for their kinase activities in vitro. We find that both autokinase and enolase kinase activities increase proportionately with the level of pp60c-src in the immunoprecipitates. To further test the authenticity of the pp60c-src encoded by the retroviral vector, these analyses were repeated in the presence of polyomavirus middle T antigen. Avian pp60c-src was activated as a protein kinase, indicating that the virally encoded pp60c-src interacts normally with middle T antigen. Interestingly, by increasing the intracellular levels of pp60c-src 15-fold over normal endogenous levels, we were unable to obtain a proportionate increase in the amount of middle-T-antigen-pp60c-src complex. Finally, using the shuttle features designed into the vector, we have isolated the first fully processed cDNA encoding functional avian pp60c-src X pp60c-src synthesized in vitro with this cDNA had intrinsic protein kinase activity and no detectable phosphatidylinositol kinase activity.

scholarly journals Natural Biology of Polyomavirus Middle T Antigen

2001 ◽  
Vol 65 (2) ◽  
pp. 288-318 ◽  
Author(s):  
Keith A. Gottlieb ◽  
Luis P. Villarreal
Keyword(s):  
T Antigen ◽  
Wild Type Virus ◽  
Wild Type ◽  
Natural Function ◽  
In Vivo Analysis ◽  
Polyomavirus Middle T Antigen ◽  
And Function ◽  
Middle T Antigen ◽  
Transforming Genes

SUMMARY “It has been commented by someone that ‘polyoma’ is an adjective composed of a prefix and suffix, with no root between—a meatless linguistic sandwich” (C. J. Dawe). The very name “polyomavirus” is a vague mantel: a name given before our understanding of these viral agents was clear but implying a clear tumor life-style, as noted by the late C. J. Dawe. However, polyomavirus are not by nature tumor-inducing agents. Since it is the purpose of this review to consider the natural function of middle T antigen (MT), encoded by one of the seemingly crucial transforming genes of polyomavirus, we will reconsider and redefine the virus and its MT gene in the context of its natural biology and function. This review was motivated by our recent in vivo analysis of MT function. Using intranasal inoculation of adult SCID mice, we have shown that polyomavirus can replicate with an MT lacking all functions associated with transformation to similar levels to wild-type virus. These observations, along with an almost indistinguishable replication of all MT mutants with respect to wild-type viruses in adult competent mice, illustrate that MT can have a play subtle role in acute replication and persistence. The most notable effect of MT mutants was in infections of newborns, indicating that polyomavirus may be highly adapted to replication in newborn lungs. It is from this context that our current understanding of this well-studied virus and gene is presented.

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