FIG. 6.

Stability of various aptamers in cell culture media (RPMI+10% fetal bovine serum), shown in an autoradiogram of a gel with various 5′ end-labeled aptamers (as indicated above lanes) incubated in culture medium for increasing times. Each set has a control (C) time 0 sample, followed by a 30-minute incubation in cell media that included nuclease (N). Either DNase I (5 units) for the DNA aptamers or RNase (0.25 μgs) for the 1.1 RNA aptamer was used. This lane is followed by samples incubated for 15, 30, 60, and 120 minutes. *For the 1.1 RNA pseudoknot aptamer, an extra lane where 20 units of RNasin RNase inhibitor was added to the media and incubated for 15 minutes is shown. Note that 38 NT SELEX [38 nucleotides (nts)] runs faster on the gel than either PF1 (30 nts) or S4 (35 nts), despite being longer. This is likely do to it being highly structured.