Effects of polyoma virus oncogenes in transgenic mice

The effects of polyoma (Py) oncogenes in transgenic mice are reviewed, with emphasis on an analysis of mice carrying individual Py early region genes linked to either the Py early region promoter or to the rat insulin II promoter. The perturbations documented in this series of animals varied with both the Py gene and the promoter. Py promoter-driven transgenes led to the development of pituitary tumors and vascular tumors in a gene-dependent manner, suggesting that the Py T antigens have different tissue specificities of transforming activity. The only pathology found in insulin promoter-driven transgenic mice was a beta cell tumor seen in insulin-promoted Py large T antigen-carrying mice. These results also suggest that the Py oncogenes have different tropisms relative to a specific cell type. Analysis of the Py oncogene-induced perturbations may provide both insights into the molecular events controlling tumorigenesis and access to rare or dispersed cell types for further analysis.