Figure 2: Numerical centrosome aberrations associated with cellular senescence. (a) Upper left panel shows a representative mitotic cell with normal morphology in a diploid subpopulation from early passage, and upper middle and upper right panels show abnormal mitotic cells with supernumerary centrosomes in a polyploid subpopulation from late passage and the 4th day after exposure to H2O2. Small red arrows indicate localization of centrosomes. Chromosomes, centrosomes, and mitotic spindles are labelled with DAPI (blue), anticentrin2 antibody (red), and anti-α-tubulin antibody (green), respectively. Lower panels show corresponding LSC data. (b) Histograms showing frequencies of mitotic cells with different centrosome numbers in a diploid subpopulation (4C) and a polyploid subpopulation (≥8C).