RNA libraries and RNA recognition

Specific Inhibition of MicroRNA Processing Using L-RNA Aptamers

In vitro selection was used to obtain l-RNA aptamers that bind the distal stem-loop of various precursor microRNAs (pre-miRs). These l-aptamers, termed "aptamiRs", bind their corresponding pre-miR target through highly specific tertiary interactions rather than Watson-Crick pairing. Formation of a pre-miR-aptamiR complex inhibits Dicer-mediated processing of the pre-miR, which is required to form the mature functional microRNA. One of the aptamiRs, which was selected to bind oncogenic pre-miR-155, inhibits Dicer processing under simulated physiological conditions, with an IC50 of 87 nM. Given that l-RNAs are intrinsically resistant to nuclease degradation, these results suggest that aptamiRs might be pursued as a new class of miR inhibitors.

RNA-RNA SELEX

Systematic evolution of ligands by exponential enrichment (SELEX) protocol is a valuable technique to identify RNA aptamers interacting with RNA structural motifs. RNA aptamers are mainly resolved with affinity column chromatography and electrophoretic mobility shift assay (EMSA). Here, we describe the separation of the RNA aptamers binding to an RNA stem-loop target with affinity chromatography using the column attached the target RNA and nondenaturing polyacrylamide gel electrophoresis to obtain a single predominant RNA aptamer family.