FIG. 7.

(A) EZH2 promotes cell cycle progression. Serum-starved MCF-7 cells were transfected with an empty vector or the wild-type (wt) or SET domain-deleted (ΔSET) EZH2 expression construct or an EZH2 siRNA construct, plus c-Myc, cyclin D1, or cyclin D2 expression constructs. Twenty-four hours after transfection, cells were treated with estrogen for another 16 h and collected for cell cycle profile analysis by cell flow cytometry. The percentages of cells in G₁, S, and G₂/M phases are shown. (B) EZH2 promoted the G₁/S transition of MCF-7 cells. MCF-7 cells were transfected with an EZH2 expression construct or an EZH2 siRNA construct. Twenty-four hours after transfection, cells were switched to normal medium (serum) or treated with 1 mM ICI 182 780 (arrested) for 24 h before adding E2 for the indicated times. The cells were then collected for cell cycle profile analysis by cell flow cytometry. The percentages of cells in G₁, S, and G₂/M phases under different experimental conditions are shown. (C) Western blotting analysis of protein expression under the indicated experimental conditions. (D) Model for EZH2 involvement in transactivation. See the text for details.