The endothelial-specific Tie2 (Tek) promoter/enhancer drives expression of the mouse Par1 (F2r) gene. The construct consists of the Tek promoter (endothelial-specific) wuth F2r cDNA and SV40 polyA sequence, followed by the Tek endothelial-specific enhancer. Selective expression of transgenic F2r can be detected by E8.0 in the endothelium and endocardium by RT-PCR. Two independent founders were generated and displayed similar results when crossed onto the F2rtm1.1Cgh background. Line 1 was chosen to designate this line.