Figure 4.
Expression of N5 death domain mutants interferes with the response of SAOS-2 cells to ionizing radiation. The indicated N5 death domain mutants were transfected into SAOS-2 cells, and successfully transfected cells were treated with 0 or 20 Gy of γ-radiation. The relative number of viable cells remaining 2 d later was determined by XTT assay. The results are expressed as the ratio of the OD490 of irradiated cells divided by the OD490 of untreated cells. The results for each sample are the mean ± SD of two independent transfections performed in triplicate.