Nucleic acid profile of the EMT6 cell cycle in vitro.

Simultaneous RNA and DNA estimations were carried out during the cell cycle of EMT6/M/CC cells growing in vitro following synchronization by mitotic selection. The determinations were performed with a flow cytofluorimeter on individual cells stained with acridine orange. It was found that the RNA content increased during G1 then remained virtually constant between early and mid S phase, but a second increase occurred during late S. The rate of uptake of tritiated uridine paralleled these changes in RNA levels, and it was also found that the rate of uptake in metaphase and anaphase was virtually zero, but a rapid increase occurred in telophase. The increase in DNA during S was approximately linear, and the intermitotic phase and cycle durations were very similar to previously reported results.