FIG. 4.

Knockout scheme and genotyping strategy. (A) The last eight exons of the Flnc gene, ∼4.1 kb, are replaced by the neomycin resistance gene flanked by loxP sites. The targeting vector was linearized and electroporated into the 129SvJ ES cell line. ES cells that had successfully recombined out the last 8 exons of the Flnc gene were screened using three different Southern probes. (B) The 5′ probe when hybridized to SpeI-digested genomic DNA was expected to show an 18-kb fragment for the wild-type allele and a 14.4-kb allele for the targeted allele. The successfully targeted cell line shows both alleles, whereas the wild-type cells show only the 18-kb wild-type allele. (C) The mice generated were genotyped using PCR. The primers used to genotype the knockout allele amplified an 800-bp product; the primers for the wild-type (WT) allele gave rise to a 490-bp product.