FIGURE 6.

Levels of C/EBPα p42 and p30 in PMA-treated THP-1 cells as well as C/EBPβ^WT and C/EBPβ^KO macrophage-like cells. A, premonocytic THP-1 cells were incubated with 100 nm PMA up to 72 h. Nuclear levels of C/EBPα p42 and p30 isoforms were determined by Western blot analysis (loading control, TBP). B, the nuclear p42/p30 ratio in three experiments performed as described in A was determined by densitometry in which the respective ratio in unstimulated cells at 0 h was defined as 1 (mean ± S.D. (error bars), n = 3). C, cells were incubated as described in A, and cytoplasmic levels of C/EBPα-p42 and LAP*/LAP were measured by Western blot analysis (loading control, actin). D, C/EBPβ^WT and C/EBPβ^KO macrophage-like cells were incubated with 100 nm PMA up to 24 h. The cytoplasmic/nuclear levels of C/EBPα proteins (p42 and p30) were determined and are indicated by arrows. TBP (nucleus) and actin (cytoplasm) were used as loading controls. n.s., nonspecific bands.