Wt1^tm1Hst

A nonsense mutation was introduced into exon 1, 12 codons downstream of the CUG start codon and upstream of the AUG start codon. A floxed hygro cassette was excised in vitro, leaving a single loxP site in a nonconserved region within in intron 1. Western blot analysis of homozygous mutant fetal kidney and testis tissue showed that while the CUG-initiated isoforms were undetected, normal levels of AUG-initiated isoforms were present. (J:82515)