Fig. 2. RANBP1 depletion hinders mitotic entry and progression in synchronously cycling cells. (A) Cell cycle progression in synchronized cultures. Cells were arrested at the G1/S boundary by double thymidine (thym) block, treated with siRNA during the second block, then released to resume cell cycle progression. RANBP1-interfered [RANBP1(i)] and control samples were harvested at regular intervals after thymidine release (time 0) and analyzed by FACS. (B) Histogram representing the proportion of cells in different phases at each time. (C) Western blot analysis of the indicated proteins in RANBP1-interfered (+) and control (–, GL2-interfered) synchronized cultures. (D) Histograms represent the MI scored in RANBP1-interfered and control cultures. ^*Significant (P<0.01) and ^**highly significant (P<0.001) differences for each time-point were evaluated using the ² test.