An FRT-flanked neomycin resistance cassette with a 5' loxP site was inserted upstream of exon 2. An additional loxP site was inserted downstream of exon 7. Flp-mediated recombination removed the selection cassette. Cre-mediated recombination removed exons 2 through 7. Western blot analysis confirmed the absence of protein expression in lung microvascular endothelial cells. (J:222474)