A bacterial artificial chromosome (BAC) clone (RP21-11805) containing the mouse Pou5f1 gene is modified to insert an optimized form of the reverse tetracycline-controlled transactivator (rtTA*M2) protein led by a KOZAK translation initiation sequence and followed by a bGHpA polyadenylation sequence and an FRT site into the initiating ATG codon of the first coding exon of Pou5f1. (J:94077)