FIGURE 3.

The inhibitors affect different aspects of the editing reaction. The radiolabeled RNA reporter for these reactions corresponds to the intermediate formed by endonuclease cleavage at an editing site. Since the reporter for the full-reaction is normally circular in order to prevent U-additions to the 3′ end, the intermediate resulting from endonuclease cleavage at the editing site is the indicated full-length linear molecule (input). In the absence of inhibitor, two guided U's are added to the linear molecule, and ligated circular product containing two U-insertions is formed. The percent inhibition for the formation of the edited circular product is relative to the DMSO-only control (n = 3). GW5074 and protoporphyrin IX only weakly inhibit the editing of the post-cleavage substrate as compared to the corresponding full reaction indicated in Figure 1C.