Model of how binding of AtCyp59 to the transcript might influence transcription. When the RRM domain (dark blue) of AtCyp59 (light blue) is not engaged in RNA–protein interaction, activity of its PPIase domain is unaffected (green). However, upon binding of AtCyp59 to the binding motif (purple) on the RNA transcript, the PPIase activity of AtCyp59 decreases (yellow). These changes might serve as a signal to modulate RNA polymerase II activity.