FIGURE 4.

Inhibition of proliferation and reduced cycling index in C/EBPβ^WT macrophage-like cells. A, C/EBPβ^WT and C/EBPβ^KO macrophage-like cells were cultivated as described (see “Experimental Procedures”) up to 72 h, and ATP proliferation assays were performed. The respective proliferation value at 0 h was defined as 1, and relative proliferation values were calculated (mean ± S.D. (error bars), n = 3). B, the cell cycle was arrested by contact inhibition, and propidium iodide staining was analyzed by FACS analysis following further incubation for 24 and 48 h (mean ± S.D., n = 3). The percentage of total cells in the G₀G₁, S, or G₂M phase, respectively, was calculated. C, for the experiments shown in B, the cycling index (S + G₂M)/G₀G₁ was calculated (mean ± S.D., n = 3). The asterisks indicate statistical significance with p ≤ 0.05.