Selective precipitation of RNA with linear polyacrylamide

Selective precipitation of RNA is often used in molecular biology as one of the methods for separation of nucleic acids to obtain samples enriched with DNA or RNA molecules alone or for purification of RNA samples. In the present study a simple and fast approach for selective precipitation of RNA with linear polyacrylamide is proposed for the first time. The method is based on the different predispositions of the DNA and RNA molecules to bind with the polyacrylamide. In this process, the linear polyacrylamide is used as the flocculant, collecting RNA particles to form aggregate, which then precipitated at low alcohol concentration. During and after precipitation the temperature is adjusted to maintain high solubility of DNA and other contaminates at given pH, salt and alcohol concentrations on the one hand, and globular state of polyacrylamide, preventing solubility of the RNA-LPA aggregate, on the other hand. The precipitated RNA can be used directly for RT-qPCR assay. The principal advantage of the present approach is the fast and quantitative precipitation of most RNA species from very dilute solutions. This makes it possible to obtain both almost DNA-free RNA and RNA-free DNA samples in one process.