UC San Diego

We intercrossed transgenic mouse lines to combine the mT/mG (“mTmG”) dual-fluorescent reporter construct with PDX1-Cre (“C”). Successful inheritance of both transgenes resulted in offspring exhibiting bright, ubiquitous tdTomato expression in all tissues except in those with PDX-1 activity, which exhibited bright green fluorescence. This new “PDX1-Cre/mTmG” line permits study of the pancreatic microenvironment and other tissues by color-coding epithelial and non-epithelial structures therein, yielding exceptionally bright and crisp images. PDX1-Cre/mTmG mice showed no apparent defects from these transgenes. The PDX1-Cre/mTmG line was then further developed to include Cre-activated pancreatic ductal adenocarcino-ma-inducing transgenes LSL-Trp53R172H (“P”) and LSL - KrasG12D (“K”). The new CKPmTmG mouse line produced color-coded, spontaneously generated pancreatic tumors. As with the PDX1-Cre/mTmG model, the CKPmTmG model enables bright and crisp microscopy and imag-ing. Further studies examined the effects of the activated KrasG12D allele on cell motility.