Generation of cortactin-deficient mice. (A) Domain organization of the cortactin protein and gene targeting strategy showing the partial genomic organization of the Cttn locus in WT, targeted, loxP-flanked (floxed), and deleted alleles. The vector carrying a neomycin resistance cassette (described previously in Lai et al. [2009]) to target the WT cortactin allele by homologous recombination in murine ES cells is depicted. Targeted ES cells were injected into blastocysts as described in Materials and methods. (B) PCR genotyping of mice carrying the WT and deleted (KO) alleles after consecutive crosses with mice expressing Flp and Cre recombinase. The top and bottom bands indicate the presence of WT Cttn allele (WT) and the deleted allele (KO), respectively. (C) Western blot analysis of different organ lysates derived from WT or cortactin-deficient mice (KO).