A loxP site was inserted into the BsaHI site in intron 1, and a loxP site and a FRT-flanked neomycin cassette was inserted into the XcmI site in intron 6. Mice carrying this allele were crossed with cre deleter mice to remove exons 2-6. Gene inactivation was confirmed by RT-PCR analysis of homozygous kidney extracts. (J:148648)