Partial cleavage and misprocessing of plant precursors. (A,B) Processing intermediates of MIR393b (A) and MIR166b (B) detected by the SPARE library. Cuts generating intermediates with single-strand cuts are indicated with an asterisk, and the scheme of these precursors are indicated on the right. (C) Scheme illustrating the cycle RT-PCR method used to map processing intermediates and the expected results for a precursor processed in a base-to-loop direction. Scheme showing the MIR172a precursor and the primers used (D), and the processing intermediates detected for MIR172a (E). The miRNAs are indicated in red and the miRNAs* in blue.