Sequence encoding cre recombinase was adjoined to Kdr promoter/enhancer sequence to drive expression of cre in the endothelial cells of the embyronic vascular system. The construct consisted of 939 bp of Kdr promoter sequence fused to cre sequence followed by a polyA signal and 2.3 kb of the first intron of Kdr. Cre-mediated recombination of a reporter transgene was observed in the embryonic vasculature at E11.5. Lines 15962 and 15964 were generated. The pound symbol (#) is used when no line is specified and/or lines are pooled.