Fig. 4.

The irreversible G₁ arrest after centrosome loss occurs via an unidentified mechanism. (A) Western blot for p53 phosphoepitopes associated with DNA damage in RPE1 cells treated with centrinone or doxorubicin as a positive control. (B) Quantification of g-H2A.X foci in RPE1 nuclei. Data are means T SD (N = 3). (C) Western blot of activated p38 in RPE1 cells. (D) Passaging assay of RPE1 cells expressing LATS1/2 microRNA, after addition of centrinone. (E) Daughter cell fate in RPE1 cells coexpressing centrin-GFP and H2B-RFP. Vertical bars represent measurements from individual daughter cells. Bar height is the time their mother spent in mitosis, and color indicates arrest (red) or division (gray). Asterisks indicate chromosome missegregation in the mother cell. Daughter cell fate after nocodazole treatment of mother cells with a normal two-centrosome complement (left) confirms the existence of a mitotic duration sensor that arrests daughter cells if the mother cell spends more than ∼84 min (black dashed lines on all plots) in mitosis. (F) Western blot of RPE1 cells treated with centrinone or R7112. (G) Passaging assay of RPE1 cells after addition (day 0) and washout (day 8) of centrinone or R7112. Data in (D) and (G) are means T SD (N = 2).