Figure 2. Absence of BRE causes impaired cell proliferation and cell cycle.

(a) Proliferation curves of WT and BRE^−/− fibroblasts expressed in fold change from day 1 when the cultures were initiated. Cell numbers were determined by proliferation assay at the indicated days. Asterisk denotes statistical significance. (b) Cumulative population doubling levels (PDL) of WT and BRE^−/− fibroblasts passaged every 3 days. (c) Cell cycle profiles of WT and BRE^−/− fibroblasts at indicated passage numbers. Cells were stained with PI and analyzed by flow cytometry. (d) The distribution of cells in G2/M and S phase shown in c is quantified as percentage values. Data shown represent the mean ± SD of three independent experiments. *denotes P-value < 0.05, **P-value < 0.01 and ***P-value < 0.001 for the difference between the WT and BRE^−/− fibroblasts.