Figure 1

Centrosome amplification in MEFs after pRb acute loss. (A) Western blot analysis showing the level of pRb expression after 3 and 30 days from the adenoviral infection: Rb^LoxP/LoxP MEF uninfected (lane 1), infected with the empty adenoviral vector (lane 2) and with the Ad-Cre at 3 (lane 3) and 30 days (lane 4). (B) Control MEFs (Rb^+/+) showed 1 or 2 centrosomes, on the contrary MEFs acutely depleted of pRb (Rb^-/-) showed the presence of supernumerary centrosomes (arrowheads). The number of centrosomes per cell was scored by microscope. Centrosomes were revealed by $\tilde{\gamma }$ tubulin and centrin detection (green) and nuclei were stained with DAPI (blue). (C) Presence of coalescent centrosomes forming pseudo-bipolar spindles in pRb deficient MEFs as shown by β- and γ-tubulin detection. (D) Time course analysis showing a decrease of cells with amplified centrosomes at 40 days from adenoviral infection. Histograms show the percentage of cells with 1, 2 or more than two centrosomes. An average of 100 cells were analyzed for each time point. Each bar indicates mean + s.e. of at least three independent experiments. (E) Representative FACScan profiles of cell cycle distribution after 30 days from the adenoviral infection in primary murine fibroblasts.