Isolation of Total RNA Using Monophasic Lysis Reagents

A typical mammalian cell contains ∼10^-5 µg of RNA, 80%-85% of which is ribosomal RNA (rRNA; chiefly the 28S, 18S, 5.8S, and 5S species). Most of the remaining 15%-20% consists of a variety of low-molecular-weight species (e.g., transfer RNAs [tRNAs] and small nuclear RNAs). These abundant RNAs are of defined size and sequence. In contrast, messenger RNA (mRNA), which makes up between 1% and 5% of the total cellular RNA, is heterogeneous in both size-from a few hundred bases to many kilobases in length-and sequence. In this introduction, the development and use of monophasic lysis reagents for the isolation of total RNA from eukaryotic cells is discussed.