Figure 6.

Systematic optimization of an aptamer variant that improves maximal expression levels and demonstration of robust regulation when an aptamer is placed in different 5′-UTR contexts. (a) Several aptamer variants generated by introducing a point mutation within Motif 1 and reducing the stem length of 5-1.2 were tested for their ability to regulate vYFP. These modifications allowed for expression level maximization while preserving regulatory range. (b) Aptamer 5-1.31 was placed within the context of several endogenous 5′-UTRs and used to control FLuc expression. In (a) and (b), numbers above the bars indicate the percent repression observed in the − Dox condition relative to the + Dox condition. In all cases, cells expressed TetR. These data show that regulation is achieved in all contexts tested.