An IRES-FlpO-loxP2272-ACE-Cre POII NeoR-loxp2272 cassette was inserted after the TAA stop codon of Slc6a4/Sert via homologous recombination in embryonic stem (ES) cells. The loxP2272-ACE-Cre POII NeoR-loxp2272 portion of the mutation is self-excised. (J:101977)