Expression of <i>GFP</i> and <i>IL2</i> Variants in Stably Transfected Flp-In T-Rex-293 Cells

<p>The <i>GFP</i> or <i>IL2</i> variants under the control of tetracycline-inducible CMV promoters were integrated into the single FRT site of Flp-In T-Rex-293 cells. Protein and mRNA was quantified in three to five individual clones for each transgene. (A) Flow cytometry measurements of GFP and EGFP protein levels 24 h post-induction. (B) Real-time RT-PCR measurements of GFP and EGFP mRNA levels 12 h post-induction. (C) ELISA measurements of the IL2 protein levels 24 h post-induction. (D) Real-time RT-PCR measurements of IL2 mRNA levels 24 h post-induction. GFP and IL2 mRNA levels were normalized to GAPDH mRNA. The controls represent CAT- transfected cells (A) or the parental Flp-In T-Rex-293 cell line (B and D). The vertical axis in each graph represents arbitrary units.