These transgenic mice express the Cre recombinase under the control of the mouse Tek, endothelial-specific receptor tyrosine kinase (also known as Tie2), promoter. Cre recombinase expression is detected in most endothelial cells and blood islands of the extraembryonic mesoderm by embryonic day (ED)7.5 and in the dorsal aorta by ED8.5. Especially high levels of expression are seen in head vasculature by ED9. When crossed with reporter strains (expressing beta-galactosidase or alkaline phosphatase), recombination is detected in all blood vessels and some blood cells examined at ED11.5, which indicates that Cre activity occurs in early vascular progenitor cells, endothelial cells and some hematopoietic cells. Mice homozygous for the transgene are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. This strain represents an effective tool for generating endothelial cell specific-targeted conditional mutations.
In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.
