Electrophoretic mobility shift assay of RNA-RNA complexes.

A simple, rapid, and sensitive electrophoretic mobility shift assay (EMSA) can be successfully used to analyze RNA-RNA interactions. The EMSA of RNA-RNA complexes can be further used to evaluate the specificity of interactions using competitor RNAs in combination with their mutated versions or nonspecific RNAs, such as yeast tRNA. RNA is simply prepared by in vitro transcription from PCR product templates. Detailed experimental descriptions for EMSA-based analysis of specific RNA-RNA interactions between Sib RNAs and ibs mRNAs as a representative example are presented.