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. Author manuscript; available in PMC: 2012 Oct 21.
Published in final edited form as: ACS Chem Biol. 2011 Aug 18;6(10):1107–1116. doi: 10.1021/cb200168y

Figure 4. proTeOff system phenotype analysis by flow cytometry.

Figure 4

Mean GFP expression and expression distribution were analyzed by flow cytometry 1, 2, 5, 10, and 20 hours post-treatment for both experimental set-ups as described. Induction experiments were repeated for all inducer concentrations and time points, and the reported trends were observed across replicates.

a. With 0 ng/ml, proTeOff upregulates GFP expression. With 10 and 200 ng/ml aTc, expression is reduced to half that of untreated samples by one hour. Steady state expression is reached by 5 hours and maintained through 20 hours post-treatment. Minimum expression is one-half and one-fifth that of untreated samples with low and high aTc respectively.

b. PROTEOFF was expressed in cells pre-cultured with 0, 10 and 200 ng/ml aTc. In 0 ng/ml aTc, proTeOff activity is observed (via GFP upregulation) one hour after PROTEOFF expression is induced. In low and high aTc, reduced proTeOff activity is observed across all times and steady state activity is achieved by 5 hours after initial PROTEOFF expression. High aTc levels maintain the reduced device activity, thus basal GFP expression. Low concentrations permit GFP levels to rise to one-third that of untreated cultures. Both of these behaviors are observed through 20 hours.