ABSTRACT
Few studies of gene expression can proceed far without analysis of the messenger RNA intermediate between gene and protein product. In some respects, RNA is simpler to work with than either proteins or DNA. RNA is tolerant of varied solvent, salt, and temperature conditions. so inactivation by denaturation-except in the rare case of double-stranded RNAs -is not a problem. It is highly resistant to shear. and can be pipeted or vortex-mixed without detriment. The overriding concern is for the activity of ribonucleases. ubiquitous in natural environments and difficult to inactivate or eliminate. We therefore include detailed descriptions of means for controlling ribonucleases.
