FIG. 3.

Progression through the cell cycle of Srf^−/− ES cells. Shown is the distribution within the cell cycle of different ES cell lines. ES cells of the indicated genotypes were cultivated under three different conditions (A to C). (A) Cell cultivation under continuous, normal growth conditions for 3 days. (B) Cells after serum starvation for 38 h. (C) Cells after serum starvation for 38 h and subsequent readdition of serum for 24 h. (A to C) Cells were stained with PI for determinations of DNA content and cell cycle distribution. The percentages of cells found in the G₁, S, and G₂ phases are shown.