Pik3r1^tm1Lca

A targeting vector was designed such that exon 7 is flanked by loxP sequences. Upon cre-mediated deletion of the exon, splicing of upstream exons 6, 1b or 1c directly into exon 8 results in a frameshift mutation producing an immediate stop codon. As a result the p85alpha isoform is truncated and p55alpha and p50alpha are essentially abolished. Flp mediated recombination removed the neo cassette. Western blot demonstrates the floxed allele is expressed just like the wild-type. (J:102176)