Wt1^tm2Asc

A GT to GG mutation at the first splice donor site of exon 9 and a floxed neo cassette in intron 9 were introduced via homologous recombination. The point mutation results in the absence of the alternative splice product with the short version of exon 9 skipping the codons at the end of the exon for the 3 amino acids KTS between zinc fingers 3 and 4 called the KTS region: only transcripts with the long version of exon 9, coding for KTS, was expressed. The neo cassette was removed by transient expression of cre recombinase in correctly targeted ES cells. RT-PCR analysis using primers to exons 9 and 10 demonstrated the presence of only +KTS transcripts in homozygous mutant animals. The -KTS transcript is completely absent. (J:71149)