Penk^{tm1.1(cre/ERT2)Hze}

A targeting vector contained a partial Penk intron 1 sequence containing an frt3 site, a partial Penk exon 2 sequence up to (but not including) the endogenous stop codon, a self-cleaving T2A sequence in-frame with the Nxph4 coding sequence, a cre/ERT2 fusion gene, a bovine growth hormone polyA signal, an AttB site, a PGK-Neo-polyA cassette, an frt5 site, an mRNA splice acceptor, the 3' portion of the hygromycin gene with SV40 polyA signal, an AttP site and genomic sequence from the Penk locus starting 509 bp downstream of the endogenous stop codon (to create a 511 bp deletion including, the stop codon). This targeting vector was electroporated into G4 ES cells. Correctly targeted ES cells were injected into recipient blastocysts. The resulting chimeric animals were bred to PhiC31-expressing mice to delete the AttB/AttP-flanked sequences and replace it with the recombined AttB/AttP site (AttL). (J:199217, J:220523)