Fig. 5

Diagram for Knock-in of Gly56Ala allele in toSlc6a4locus. The targeting vector with the Ala56 knock-in mutation contained a floxed positive selection Neomycin-resistance cassette and a negative selection thymidine kinase cassette. Recombination with 129S6 embryonic stem cell DNA resulted in an Slc6a4 gene containing the Ala56 knock-in mutation, as well as two loxP sites surrounding the Neomycin-resistance cassette in intron 4. Breeding with Protamine (Prm) Cre transgenic mice yielded excision of the floxed Neomycin-resistance cassette with retention of a residual loxP site in intron 4