Figure 1.

Inhibition of polβ polymerase activity by RNA aptamers. (A) Primer extension reactions containing 4 nM polβ and 300 nM 5′-³²P-labeled primer-template were performed as described in Materials and Methods in the absence (lane 2) or presence of 48 nM (lanes 4, 6, 8, 10, 12, 14, and 16) aptamer or 480 nM (Lanes 3, 5, 7, 9, 11, 13, 15) as labeled. Reactions were then quenched and products were analyzed by denaturing PAGE. Lane 1 represents a control reaction carried out in the absence of polβ. (B) Bar graph showing quantification of the polymerase activity in each reaction calculated by summing the product of the band intensity and the number of nucleotides that had been added to the primer under the assumption of completely distributive addition. This value for lane 2, polβ activity in the absence of aptamer was set to 100% and the other lanes normalized to this value. For each aptamer, the black bars, 48 nM and gray bars, 480 nM.