FEN1 incises 5’ RNA flap differently from the DNA counterpart.

<p>(<b>A</b>) FEN1 endonuclease assays were performed with increasing amounts of FEN1 (0.25, 0.5, 1, 2, 4, 8 nM) with both the 15-nt DNA and RNA 5’ flaps (2 nM). Diagrams of the 5’ flap substrates were shown on top of each set of reactions. Reaction products (indicated by an arrow) were resolved in 10% denaturing polyacrylamide gel. (<b>B</b>) Quantitation of FEN1 endonuclease assays in A by incision rate. Error bars represent standard deviations of three independent experiments. *, p<0.05 when compared the RNA and DNA flap reactions within the same FEN1 concentration.