MicroRNAs (miRNAs) are non-coding RNAs that impact almost every aspect of biology. In recent years, they have been strongly implicated in stem cell biology, tissue and organism development, as well as human conditions ranging from mental disorders to cancer. For the most part, miRNAs control gene expression of messenger RNA (mRNA) targets. Unlike mRNAs, which are translated into proteins, miRNAs function as short, untranslated molecules that regulate specific mRNAs through base-pairing interactions. Since miRNAs bind limited stretches of consecutive bases in mRNAs, identifying which mRNAs are targets of individual miRNAs has been a bottleneck of biomedical research, as researchers have had to rely largely on computational predictions.
Now, researchers at the University of California, San Diego have identified the binding sites of these miRNAs in one of the foremost model organisms, C. elegans, using biochemical means to capture targeted mRNA sequences in vivo.