Electrophoretic analysis of cleavage of radiolabeled pri-miRNA substrates by the microprocessor. The concentration of 12 is indicated above each lane containing microprocessor. Size standards (215 nt, 149 nt, and pre-miR-16, generated as described in Materials and Methods) correspond to the products of cleavage of pre-miR-16 from the pri-miR-16 substrate without degradation of the flanking sequences. Arrows indicate the positions on the gel of the pre-miRNA products. Products smaller than the pre-miRNA are labeled with an asterisk. (A) Comparison of effects of 12 on microprocessor cleavage of pri-miR-16 and pri-miR-21. (B) Effect on microprocessor cleavage of a derivative of 12 in which the guanidinium side chain is replaced with a methyl group. (C) Comparison of the effects of 12 on microprocessor cleavage of pri-miR-16 and pri-miR-16 with the apical loop of pri-miR-21. The loop regions are shown above the gel, with the loop sequences that distinguish the two substrates shaded. (D) Comparison of the effects of 12 on microprocessor cleavage of pri-miR-21 and pri-miR-21 with the apical loop of pri-miR-16. The loop regions are shown above the gel, with the loop sequences that distinguish the two substrates shaded.
