A floxed neo cassette was inserted into intron 10 and a G to A mutation, resulting in a premature stop codon at position 516 (W516X), was inserted into exon 11 via homologous recombination. Cre mediated recombination removed the neo cassette. RT-PCR indicates a significant reduction in expression in kidneys in homozygous and heterozygous mice. Immunofluorescence analysis failed to detect protein expression in kidneys from homozygous mice.