FIG. 5.

The arginine-rich motif of Rex interacts specifically with aptamer 8-5. (A) The Rex protein interacts specifically with aptamer 8-5. Increasing concentrations of Rex or Rev were individually mixed with end-labeled clone 8-5, and complexes were separated on an 8% native polyacrylamide gel (19:1, 1× TBE, 5 W, ambient temperature). (B) The Rex ARM interacts specifically with a minimal version of aptamer 8-5. Peptides spanning the ARMs of Rex or Rev were titrated against a constant amount of an end-labeled, minimal version of aptamer 8-5. The minimal version of aptamer 8-5 was used in order to allow a larger electrophoretic separation between free and complexed RNA molecules. Complexes were separated on a 10% native polyacrylamide gel (59:1, 0.5× TBE, 350 V, 4°C).