Figure 4.

Purification of aptamer D8 from a complex mixture of human cellular RNA using Sephadex G-100. Radiolabeled aptamer D8 RNA and the control RNA (5 × 10⁴ c.p.m. or 30 ng each) were added to 10 µg unlabeled cellular RNA. The sample was incubated with 200 µl of Sephadex beads in 500 µl total volume, washed and eluted as detailed in Materials and Methods. (A) Samples from each fraction, i.e. input, unbound, wash and eluate, were analyzed for total cellular RNA by electrophoresis on a native 2% agarose gel and stained with ethidium bromide. (B) The radiolabeled RNA in the same fractions was analyzed by electrophoresis in a 10% denaturing polyacrylamide gel and visualized with a PhosphorImager system. The ratios of aptamer D8 to the control RNA were calculated to show the enrichment of purification and are shown below each lane.