Figure 5.

The expression of TEL1 has no effect on basic p53 protein levels and IR-induced p53 accumulation in A-T cells. Nuclear extracts were prepared following 10-Gy IR and p53 protein was detected in Western analyses (A). Normal GM637 cells showed a time-dependent p53 accumulation upon IR, while TEL1-transfected A-T cells failed to accumulate p53. This typical A-T deficiency also was confirmed in A-T control cells (not shown). (B) p53 protein was shifted with oligonucleotides containing the p53 consensus sequence from GADD45, again showing the clear accumulation of active, DNA-binding p53 protein upon IR in normal GM637 cells. Neither A-T cell line showed an accumulation of DNA-bound p53 upon IR. Supershift analyses using anti-p53 antibody pAb421 confirmed the specificity of the shifted p53 bands (C).