A targeting vector was designed to insert a loxP site upstream of exon 3 followed by a neomycin resistance (neo) cassette flanked by frt sites and loxP sites downstream of exon 3 of the angiotensin II receptor, type 1a (Agtr1a) gene. Flp-mediated recombination removed the neo cassette and left exon 3 floxed. (J:192945)