A targeting vector was designed to replace the Stk33 locus between exon 6 and exon 8 with a cassette containing exon 7 of Stk33, a neomycin resistance gene flanked by FRT sites, and loxP sites surrounding exon 7 and the neomycin cassette. The neomycin cassette was removed through Flp-mediated recombination via crossing to ACTB:FLPe B6J mice to obtain the conditional strain that contains loxP recombination sites flanking exon 7 of Stk33. (J:253666)