The entire open reading frame of the gene, encoded by a single exon, was replaced with a tTA-IRES-hPLAP-ACN targeting cassette. Tetracycline transactivator (Tta), an internal ribosome entry site (IRES), and human placental alkaline phosphatase (hPLAP) are fused with a self-excising loxP-flanked pol-II promoter-neomycin resistance cassette (ACN). Cre-mediated recombination removed the neo cassette. (J:101977)