Recovery of RNA from flow-sorted fixed cells.

We describe a method for the preparation of RNA from ethanol-fixed cells, allowing analysis of the RNA from cells "frozen" in a given physiological state. This technique may have important applications in experiments which require prolonged cell manipulations before RNA preparation, such as investigations of cell-cycle-regulated gene expression, which require the preparation of cells for cell-cycle flow analysis, and even for long-term cell sorting. It eliminates all the inconveniences associated with the use of fresh cells, and allows cell-cycle biologists to couple flow cytometry methodology with the advancing techniques of molecular biology.