FIG. 7.

Us11 RNA binding domain directly binds double-stranded RNA. (A) Labeled poly(I · C) was incubated with increasing amounts of purified GST Δ1-87, and the amount of radioactivity retained on a nitrocellulose filter for each sample was determined. (B) Ten nanograms of GST Δ1-87 was incubated in the presence of labeled poly(I · C) in the absence of competitor or with increasing amounts of an unlabeled RNA selected to bind Us11 (L12-5 [▴]), an unlabeled RNA from the initial unselected population (▪), or unlabeled poly(I · C) (♦). The amount of radioactivity retained on a nitrocellulose filter for each sample was determined. RNA binding in the absence of competitor was normalized to 1.0. (C) Binding to labeled poly(I · C) was as described for panel B with the modification that the reaction mixtures contained increasing amounts of either unlabeled poly(A) (▪), poly(C) (•), poly(U) (▴), or poly(I · C) (♦).