p21 and p53 expression after chromosome missegregation. (A) HCT116 cells that have properly segregated (top) or missegregated (bottom) the marked chromosome 24 h after no treatment (top) or monastrol washout (bottom) were stained for p21, p53, and DAPI and with LacIGFP as indicated. (B) Percentage of nuclei staining positive for p21 and p53 24 h after control and monastrol washout in populations of HCT116 (left) and RPE1 (right) cells. Bars represent mean ± SEM of at least three experiments (>300 nuclei counted per condition per experiment). (C) Percentage of nuclei staining positive for p21 and p53 in chromosomally marked HCT116 cell line after control or monastrol washout in pairs of daughter cells that have either properly segregated or missegregated (mis-seg) the marked chromosome. Bars represent mean ± SEM of >180 cells in at least three experiments. (D) Immunoblots of untreated (ctrl) cells or cells after monastrol washout (mon) probed for p21, p53, and tubulin (loading control) in HCT116 and RPE1 cells. Bar, 10 µm.