The targeting vector contained, from 5' to 3', a partial Slc17a7 sequence spanning exon 1 through intron 9, an frt3 site within Slc17a7 intron 9, a partial Slc17a7 exon 10 sequence including the endogenous stop codon, an internal ribosome entry site 2 (IRES2) sequence , a Cre recombinase gene, a bovine growth hormone polyA sequence, an AttB site, a PGK promoter-Neomycin resistance gene-PGK polyA cassette, an frt5 site, an mRNA splice acceptor, the 3' portion of the hygromycin gene with SV40 late polyA signal, and an AttP site. This construct was electroporated into G4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts. Chimeric mice were bred to PhiC31-expressing mice to remove the AttB/AttP-flanked sequences (PGK-Neo-polyA::frt5::RNA splice acceptor::3'hygro-polyA) and replace it with the recombined AttB/AttP site (AttL). The resulting Slc17a7-IRES2-Cre-D mice were bred with C57BL/6J wildtype mice for several generations to remove PhiC31 transgene. (J:146821, J:220523)