Figure 1.

The pRetro-off vector with the IL-10 gene insert. The tetracycline (Tc)-controlled transactivator (tTA) is expressed from the integrated retroviral constructs tetR and VP16. In this vector, tTA binds the tet-responsive element (TRE), activating transcription only in the absence of Tc or its derivative doxycycline (Dox). P_CMV is the promoter for cytomegalovirus. In addition, the vector includes genes for puromycin-resistance and ψ⁺, the packing signal for retrovirus particle formation. IL-10 was inserted in either the sense or antisense direction to produce Ret-off-IL-10 sense and Ret-off-IL-10 antisense, respectively. (Figure modified from Clontech retroviral Tet vector user manual PT30001-1, page 6.)