Cell cycle analysis

Before analysis, the cells are usually permeabilised and treated with a fluorescent dye that stains DNA quantitatively, such as propidium iodide (PI) or 4,6-diamidino-2-phenylindole (DAPI).

An arrest of cells in G0 or G1 is often seen as a result of lack of nutrients (growth factors), for example after serum deprivation.

Cell cycle analysis was first described in 1969 at Los Alamos Scientific Laboratory by a group from the University of California using the Feulgen staining technique.

[1] The first protocol for cell cycle analysis using propidium iodide staining was presented in 1975 by Awtar Krishan from Harvard Medical School and is still widely cited today.

The concurrent measurement of cellular DNA and RNA content, or DNA susceptibility to denaturation at low pH using the metachromatic dye acridine orange, reveals the G1Q, G1A, and G1B cell cycle compartments and also makes it possible to discriminate between S, G2 and mitotic cells.

Aside from propidium iodide and acridine orange, quantifiable dyes that are frequently used include (but are not limited to) DRAQ5, 7-Aminoactinomycin D, DAPI and Hoechst 33342.