An 852 bp fragment of intron 1 of the mouse Cdx2 gene containing a neural specific enhancer was cloned upstream of a cre recombinase expression cassette. The cre cassette contains an Hsp68 minimal promoter, the cre recombinase open reading frame and the SV40 polyadenylation sequences. This construct was injected into (C57BL/6 x C3H) oocytes. Thirteen F0 founders were obtained with 8 testing positive for cre activity. A single male, R337, was bred to a wild type B6 female.