The Pax8-rtTA construct contains an optimized rtTA variant (rtTA2s-M2) cDNA and SV40 polyA sequence replaced at the endogenous ATG translational start site of a murine Pax8 sequence. The rtTA2S*M2 variant contains 5 amino acid changes in the TetR moiety (S12G, E19G, A56P, D148E, and H179R) and a synthetic optimized transactivating domain, resulting in reduced basal activity and enhanced doxycycline sensitivity compared to wild-type rtTA. (J:140925)