Figure 4.

SON deficiency results in defective cytokinesis and induces cell death. (A) SON depletion is accompanied by aberrant chromosome segregation. Representative images showing SON-depleted cells with defective cytokinesis and quantification of the number of internuclear bridges indicative of chromosome missegregation. (B) SON deficiency is associated with abnormal nuclear morphology. Quantification and representative images showing cells with abnormal nuclei in the absence of SON protein. siRNA-treated cells were fixed, permeabilised and immunostained with indicated antibodies. (C) SON depletion results in cell death. Following siRNA transfection, cells were harvested at different time points (24–60 hr post-transfection). Representative cell cycle profiles of control (siCTR) or SON-specific siRNA (siSON-mix)-treated cells. Cells were fixed in 70% ethanol, stained with propidium iodide and subjected to flow cytometry analysis. Percentages of sub-G₁ cell populations (M1) are shown.