A neomycin cassette replaced the entire coding region (exon 2 through the stop codon in exon 10). RT-PCR analaysis of kidney and liver tissue showed an absence of transcript in homozygous mutant mice. Western blot analyses of unactivated and activated plasma confirmed a lack of encoded protein in homozygous mice. Complex formation was undetectable by blotting analysis of plasma incubated with purified plasmin. (J:43244, J:54047)