The targeting vector is designed to insert a loxP site, a a wild-type Npr2 minigene with 200 bp of intron 8 and cDNA from exons 8-22 (from BAC vector, RP24-306K11 and full length Npr2 cDNA), an IRES/EGFP reporter, an FRT-flanked PGK neomycin cassette and a loxP site into intron 7 and insert the 7E point mutations into exons 8 and 9. The 7E point mutations consist of 7 glutamate substitutions: S489E, S513E, T516E, S518E, S523E, S526E, T529E. Flp-mediated recombination removed the neo cassette. (J:228790)