The 4.5 kb region containing Pdx1 regulatory sequences was used to drive expression of a cre recombinase constructed modified with a nuclear localization signal upstream of a human hGH minigene. The Pdx1 promoter drives expression in the pancreas. Mosaic cre expression is first observed in the pancreatic epithelium at E11.5. Expression continues to be mosaic at E12.5. (J:78865, J:108521)