The TAG stop codon was replaced with the "P2A-CreERT2" cassette. CreERT2 recombinase is expressed under the regulatory control of Prox1 gene elements. This model is a Tamoxifen-inducible Cre mouse, and when crossed with mice containing loxP sites, the offspring mice are expected to undergo sequence recombination between loxP sites mediated by Cre recombinase in lymphatic endothelial cells following Tamoxifen induction.