Tg(Tph2-cre/ERT2)1.38Zi

A 177 kb PAC (P1-derived artificial chromosome; pPAC4) containing the full-length murine Tph2 gene and flanking sequences were modified by recombineering methods in EL250 bacteria prior to use for transgene construction. First, a chloramphenicol resistance gene replaced the kanamycin gene in the PAC backbone. Then a cassette encoding cre fused to a mutated human estrogen receptor (ER) ligand-binding domain (LBD; creERT2) and an FRT-flanked kanamycin resistance gene was integrated into the ATG start codon. A 23 bp sequence downstream of the ATG codon was deleted as it contained other in-frame ATG start sites in exon 1 of Tph2. Arabinose-induced FLP expression deleted the kanamycin cassette. The modified Tph2 sequence was excised from the PAC backbone and purified for injection into C57BL/6N oocytes. Five founder lines were obtained (1.21, 1.23, 1.27, 1.35, and 1.38). Lines 1.21 and 1.38 produced the highest recombination efficiency in serotonergic neurons with tamoxifen induction (91 and 90% respectively). Line 1.38 was investigated most extensively. (J:164111)