The murine EPCR transgene, consisting of 750 bp murine Procr cDNA and 400 bp SV40 polyA signal sequence was ligated to the murine 2.1 kb Tek promoter. The murine Tek enhancer fragment, extending from a Nae I site of exon 1 approximately 10 kb into the first intron was ligated downstream of the SV40 polyA sequence.