Murine polyomavirus provides an important model for neoplastic transformation. The virus causes a broad spectrum of tumors. Conclusions reached in the laboratory can be readily tested in animals. Studies on polyoma have repeatedly provided insight into basic mechanisms of cellular growth regulation. Tyrosine kinase and phosphatidylinositol 3-kinase (PI3K) signaling are two fundamental mechanisms uncovered from studies on polyoma. Transformation results from the action of three viral gene products: large T (LT), middle T (MT) and small T (ST) antigens. There are four specific aims that will provide new insight into how they work: 1) the first specific aim concerns large T. Patterns of host cellular RNA expression that result from different large T pathways will be determined. The mechanism will be established by which LT regulates genes containing CREB/ATF sites. Because acetylation has been connected to transcriptional regulation, the sites of acetylation on LT will be established and their function tested by site-directed mutagenesis. Recent results show that LT causes G2/M arrest. Experiments will be carried out to determine the mechanism by which LT causes this arrest. We have identified two new LT-binding partners, Pinl and Bubl, which are known regulators of G2/M. Their role in LT function will be probed. 2) The second specific aim concerns small T. Important differences in function have been detected between polyoma and SV40 small T. Expression profiling will be used to identify the extent of, and the basis for, the differences between them. New polyoma small T partners will be sought by tandem affinity purification and mass spec. Protein phosphatase 2A is a critical small T target. Experiments will be performed to distinguish between different mechanisms by which small T targets PP2A. 3) Human mammary epithelial cells provide a useful model of human cancer. The third specific aim will use the model to probe the function of middle T and small T. The MT signaling pathways required for transformation will be determined. Small T mutant in binding novel partners will be tested in these cells. 4) Our fourth specific aim involves structural studies using NMR. The structure of the N-terminal domain (NT) of LT will be determined. This domain is sufficient to promote cell growth, to cause apoptosis and to regulate cellular RNA transcription. We will also initiate studies to carry out structure determination of polyoma small T.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
2R01CA034722-22A1
Application #
6870688
Study Section
Virology Study Section (VR)
Program Officer
Read-Connole, Elizabeth Lee
Project Start
1983-04-03
Project End
2009-07-31
Budget Start
2004-09-30
Budget End
2005-07-31
Support Year
22
Fiscal Year
2004
Total Cost
$449,826
Indirect Cost
Name
Tufts University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
039318308
City
Boston
State
MA
Country
United States
Zip Code
02111
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Hwang, Justin H; Jiang, Tao; Kulkarni, Shreya et al. (2013) Protein phosphatase 2A isoforms utilizing A? scaffolds regulate differentiation through control of Akt protein. J Biol Chem 288:32064-73
Banerjee, Pubali; DeJesus, Rowena; Gjoerup, Ole et al. (2013) Viral interference with DNA repair by targeting of the single-stranded DNA binding protein RPA. PLoS Pathog 9:e1003725
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Lee, Sang Hyun; Jia, Shidong; Zhu, Yanni et al. (2011) Transgenic expression of polyomavirus middle T antigen in the mouse prostate gives rise to carcinoma. J Virol 85:5581-92

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