Fig. 3.

A sliding-bulge structure caused alternative Dicer processing in miR-203. (A) The sliding-bulge structure is conserved across species. The box indicates the sliding bulge with the extended duplex that helps to maintain the bulge structure. (B) pre-miR-203 can have two different structures, depending on which A (at positions 1 or 2) pairs with the U nucleotide. The box indicates the sliding-bulge structure. (C) Dicer cleavage sites in miR-203 mutants with a fixed bulge. The A at position 1 was mutated to C so that the miR-203 A1→C mutant had the fixed bulge of structure 1, while the A at position 2 was mutated to U so that the miR-203 A2→U mutant had the fixed bulge of structure 2, as shown in (B). Dicer processing sites were determined as in Fig. 1A. (D) Northern blot to visualize the mature miR-203 derived from the indicated mutants. Please see Fig. 8S in the Supplementary Material for full blot images.