Figure 1.

(A) Predicted anti-NF-κB RNA aptamer secondary structures. Full-length R1, full-length anti-p50, and 31-nt version of anti-p50 (bracket) are depicted with 5′ terminal nt circled and nt of the non-randomized regions of R1 shaded. The trinucleotide G_67–69 feature of R1 is underlined. (B) Screening RNA libraries using the Y3H. Transcription of lacZ and HIS3 reporter genes (filled arrow at right) depends on a tri-molecular interaction between integrated hybrid protein 1 (LexA/MS2 coat protein fusion, top), a hybrid protein 2 (GAL4AD/NF-κB family member, middle), and a hybrid RNA composed of the MS2 recognition sequence and an early round or degenerate R1 library sequence cloned into the MS2 plasmid by homologous recombination (bottom).