MicroRNAs (miRNAs) are an important class of non-coding regulatory RNAs, which interfere with the translation of protein-coding mRNA transcripts. By incorporation into the RNA induced silencing complex (RISC), miRNAs can inhibit translation, promote sequestration of mRNAs to P-bodies, and/or destabilize and degrade target mRNAs. The small size of mature miRNAs (typically only 20 to 24 nucleotides) makes them ideal for characterization using short-tag RNA-sequencing (RNA-seq) technologies as you can capture the entire molecule in a single read. Unlike hybridization approaches such as microarray profiling or Northern blotting, massive-scale sequencing provides a way to discriminate discrete but closely related RNA molecules, and profile miRNAs without a priori knowledge of expression.

MicroRNAs perform their biological roles by binding to mRNAs through Watson-Crick base-pairing. The attractive simplicity of using nucleotide complementarity to identify mRNA targets has given rise to many bioinformatics tools. These are based (to differing extents) on complementarity to the seed, evolutionary conservation, and free energy of binding.

So with great technology and plenty of well researched and well respected bioinformatics tools, miRNAs should be easy, right? This talk will systematically crush this rosy view of miRNAs as a field of study, and lay before you the desolate wasteland to navigate on your path to publication. Those towards the end of their PhD study on miRNAs may wish to avoid this talk.