MiR159a variants with up to two central mismatches can direct target cleavage at the canonical miR159 cleavage site.

<p>(A) Schematic representation of <i>MYB33</i> PCR products after a modified 5′-RACE procedure to determine the proportion of degraded <i>MYB33</i> mRNA that corresponds to miR159-guided cleavage products. Red box: RNA Oligo adaptor; Yellow box: <i>MYB33</i> sequences; Red arrow: canonical miR159 cleavage site; Green arrow: <i>MYB33</i> sequencing primer. (B–E) Sequencing chromatographs of the cDNA-adaptor region from 5′-RACE recovered 3′ <i>MYB33</i> transcripts in: (B) Col-0, (C) <i>mir159ab</i>, (D) <i>MIR159a1</i> and (E) <i>MIR159a2</i> plants. Peaks from <i>MYB33</i> sequence downstream of the miR159 cleavage sites are highlighted in yellow, while those from the adaptor are left white. Three independent transgenic lines were checked for each construct and the results were identical.