Chromosomal instability in 3MC-fibrosarcoma cell lines.

aThe functional status of p53 in the fibrosarcoma cell lines was determined by examining the levels of p53 and p21 upon γIR, both by immunohistochemistry (Fig. 5A) and immunoblotting (Fig. 5B), as well as, by their susceptibility to cell cycle arrest upon treatment with nutlin (Supplementary Fig. S5 and S6).
bThese Atm-null lines with functional p53 correspond to a minority of the 3MC-fibrosarcomas produced in Atm-null mice, which by large have mutant p53 (see Table 1 and Fig. 5B). Only two lines were obtained that retained functional p53 (Supplementary Fig. S6): one derived from an Atm-null;p53-super mouse and the other one from an Atm-null;p53-wt mouse.
cAneuploidies correspond to metaphasases with chromosome numbers different from 40±1 or 80±2.
dStatistical comparison (t-test) between Atm-null(p53-functional) and Arf-null(p53-functional): metaphases with fusions, p = 0.04; aneuploid cell lines, p = 0.06.