FIGURE 1:

The induction of histone H4 expression was required for mitotic clonal expansion and terminal differentiation of 3T3-L1 preadipocytes. (A) Postconfluent 3T3-L1 preadipocytes were induced to differentiate as described, total RNA was isolated at different time points, and quantitative real-time RT-PCR was performed to detect histone H4 expression. (B–E) 3T3-L1 preadipocytes were transfected with histone H4 siRNA, and 24 h after reaching confluence, cells were induced to differentiate as described. Total RNA was isolated at 20 h after induction, the expression of total H4 was detected by real-time RT-PCR, and 18S rRNA was used as loading control (B). After 8 d of induction, fat droplet accumulation was detected by oil red O staining and photographed (C), and the expression of PPAR γ and 422/aP2 was detected by Western blotting; actin was used as loading control (D). DNA content was analyzed by fluorescence-activated cell sorting, and the percentage of cells in S phase or G0/G1 phase was calculated at 0- and 20-h time points (E).