A PGK-driven neomycin resistance gene flanked by FRT sites and followed by a loxP site were inserted 200 bp before exon 8 and another loxP site was inserted 200 bp after exon 9. Germline Cre-mediated recombination removed exons 8 and 9 and this is predicted to cause a frame shift resulting in a protein truncated at amino acid 405. (J:237108)