A streamlined protocol for extracting RNA and genomic DNA from archived human blood and muscle

We combined the TRIzol method of nucleic acid extraction with QIAamp columns to achieve coextraction of RNA and genomic DNA from peripheral blood mononuclear cells (PBMCs) and biopsied skeletal muscle, both stored at -80 °C for many months. Total RNA was recovered from the upper aqueous phase of TRIzol. The interphase and organic phases were precipitated with ethanol, digested with proteinase K, and filtered through QIAamp MinElute columns to recover DNA. The combined protocol yielded excellent quality and quantity of nucleic acids from archived human PBMCs and muscle and may be easily adapted for other tissues.