Quantitative RT-PCR Specific for Precursor and Mature miRNAs

Quantification of microRNAs (miRNAs) in cells or primary tissues is one of the most important steps in elucidating their biological functions. However, miRNAs are challenging molecules for PCR amplification due to the stable hairpin of the precursor form and the small size of the mature miRNA, which is roughly the same length as the primers used in standard PCR. To date, different assays were introduced for the specific and sensitive quantification of the mature form of miRNAs. In this chapter we describe the extraction of RNA from microdissected tissue and the quantification of miRNAs using two different methods (stem–loop qRT-PCR and polyT adaptor qRT-PCR).