Transgenic mice for Cre-inducible overexpression of the oncogenes c-MYC and Pim-1 in multiple tissues.

The transcription factor c-MYC and the serine-threonine kinase Pim-1 have multiple roles in development and cancer, including in lymphomagenesis and prostate tumorigenesis. In some cancers, MYC and Pim-1 oncogenes are co-expressed and show marked cooperativity. To facilitate the analysis of the pathological roles of MYC and Pim-1 in specific cell types and developmental stages, we generated mice carrying Cre-inducible MYC/Pim-1 transgenes. The mice carry a constitutively expressed lacZ marker and silent MYC/Pim-1 genes. Cre-mediated recombination results in deletion of the lacZ marker and concurrent activation of the MYC/Pim-1 transgene. In addition, the Pim-1 mice harbor an alkaline phosphatase gene as a positive marker for recombination. Mouse lines for each gene were established, which show distinct patterns of expression in multiple tissues. In vivo recombination was confirmed for all lines by breeding to Cre transgenic mice. These mice provide a valuable resource for investigating the significance of MYC and Pim-1 overexpression in various tissues.