The gene was disrupted by replacement of part of exon 1 (just upstream of the translation initiation codon) to part of exon 2 (after the conserved VIRAK codons) with a neomycin resistance cassette in the reverse orientation. Northern blot of lung, kidney, and heart RNA and RT-PCR analysis did not detect gene expression in homozygous mutants. Reverse zymographic analysis of kidney extracts did not detect protein activity in homozygous animals. (J:71609)