Single-step technique, cells are homogenized in guanidnium thiocyanate and the RNA is purified from the lysate by extraction with phenol:chloroform at reduced pH. Many samples can be processed simultaneously and speedily. The yield of total RNA depends on the tissue or cell source and is generally in the range of 4-7 µg/ml starting tissue or 5-10 µg/106 cells. IMPORTANT: Prepare all reagents used in this protocol with Diethyl pyrocarbonate (DEPC)-treated H2O. - [Read Purification of RNA from Cells and Tissues by Acid Phenol-Guanidinium Thiocyanate-Chloroform Extract]