Atm^tm1.1Mmpl

Two loxP sites were inserted into the introns surrounding to exon 4. Flp-mediated recombination removed the FRT-flanked neomycin resistance cassette inserted into intron 3. Cre-mediated recombination removed exon 4. This allele is predicted to cause a frameshift mutation through the splicing of exon 3 to exon 5. Western blot analysis confirmed the absence of protein expression in fibroblasts. (J:226414)