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Figure 3 | BMC Biotechnology

Figure 3

From: Improved Tet-responsive promoters with minimized background expression

Figure 3

Retroviral transfer of the new Ptet promoters. (A) The different regulatory units were inserted into the γ-retroviral self-inactivating (SIN) vector „ES.1". The U3-enhancer elements (ΔU3) were deleted from the provirus, while the enlarged packaging region (ψ,ψ+) as well as the native splice acceptor (SA) located in the pol/env region of the virus were retained. In order to enhance viral titers and translational efficiency, a woodchuck posttranscriptional regulatory element (WPRE) was integrated 3'-to the reporter gene. (B) The lmg* dual reporter was used throughout all experiments with the viral vectors. The corresponding gene consists of the firefly luciferase open reading frame (orf), with deleted stop codon, the 3'-half of the troponin C α-helix5 and the eGFP orf with the deleted start codon. (C) Left panel: Determination of specific luciferase activity (relative light units, rlu) that were obtained from transduced, FACS enriched HtTA-1 cell populations. Statistical comparison was done as described in figure 2. Right panel: Regulation factors for the individual Ptet promoters from the analysis shown left. The results shown are derived from at least two cell populations generated independently. Each population was analyzed two to three times; the error bars represent the SEM.

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