Differential staining of DNA and RNA.

Cell cycle analysis by means of differential staining of RNA and DNA permits determination of RNA content, which in turn allows one to discriminate G(0) versus G(1) cells and to detect cell differentiation. This unit presents two protocols for differential staining, one using the metachromatic dye acridine orange (AO) and the other a combination of pyronin Y (PY) and Hoechst 33342. Each method has its advantages and limitations, and the Hoechst-PY method is not applicable to single-laser instruments. A third protocol describes staining of viable cells to identify/sort hematopoietic stem cells, with an alternative that includes simultaneous immunostaining.