Activation of transcription readthrough by AICA derivatives in vitro. (a) Example single-round transcription termination assay for 8 (0, 1.0, 2.0, 3.9, 7.8, 15.6, 31.3, 62.5, 125, 250 μM, left to right). Readthrough (RT) and terminated (T) transcription products are labeled. (b) Transcription termination for 7 (blue), 8 (red), and 1 (black) (n = 3 independent experiments).