Table 1.
ARF dependence of p53-mediated stress responses
| MEFs | % S γ/% S untreated
|
% BrdUrd-positive
|
Polyploidy T48 Noc | |||||
|---|---|---|---|---|---|---|---|---|
| 5 Gy | 6 Gy | 7 Gy | 20 Gy | Untreated | T72 PALA | T24 Act-D | ||
| p53+/− | 39.6 ± 0.5 | 36.9 ± 1.8 | 34.4 ± 5.2 | 25.9 ± 4.5 | 22.8 ± 2.4 | 12.0 ± 3.1 | 5.1 ± 0.1 | 6.5 ± 3.4 |
| p53−/− | 101.0 ± 1.4 | 100.8 ± 3.2 | 105.2 ± 8.3 | 83.5 ± 0.7 | 24.4 ± 3.8 | 27.7 ± 3.3 | 20.8 ± 5.4 | 60.1 ± 2.2 |
| p19ARF−/− | 75.0 ± 9.9 | 85.0 ± 2.8 | 81.5 ± 0.7 | 64.5 ± 0.7 | 19.7 ± 1.2 | 6.9 ± 2.6 | 4.6 ± 0.5 | 26.1 ± 4.9 |
Asynchronous populations of p53+/−, p53−/−, and p19ARF−/− MEFs were irradiated with 5, 6, 7, or 20 Gy, pulse-labeled with BrdUrd, and fixed 24 h later. The values represent the percentage of BrdUrd-positive cells in γ-irradiated cultures (% S γ) relative to untreated. Cells were also untreated or treated with 100 μM PALA for 72 h or 5 nM actinomycin D for 24 h, and the percentage of BrdUrd-positive cells is shown. The polyploid fraction was assessed by treating cells with 0.05 μg/ml nocodazole for 48 h and quantitating the percentage of cells with >4N DNA content. The values represent the mean of at least two independent experiments and standard deviations are shown.