Tetracycline inducible expression, lowest background.
The PTRE3G promoter results in significantly reduced basal expression. HEK 293 cells were transiently cotranstected with both the response vectors (containing luciferase) and regulator vectors from each of the Tet-On 3G and Tet-On Advanced Inducible Expression Systems. The cells were cultured in the presence and absence of Dox, and after 24 hr, luciferase expression was measured. Although both systems provided strong expression in the presence of Dox, the Tet-On 3G System produces far lower background expression in the absence of Dox (inset).