LoxP sites were inserted to flank exon 3 of the Shoc2 (Sur-8) gene. The targeting vector also contained an frt-flanked neomycin resistance cassette. The vector was electroporated into W4 ES cells. Mutant mice were crossed to Actin-FLPe transgenic mice to remove the neo cassette, leaving the floxed allele. (J:161211)