Figure 1.

Impaired DNA damage response in the absence of nuclear PTEN. PTEN-deficient U87MG glioblastoma cells were stably reconstituted with either empty vector (control), wild-type (WT) PTEN or PTEN K254R mutant. The resulting cell pools were exposed to 5 Gy of γ irradiation and monitored at 30 minutes and 24 hours for PTEN expression (green) and 53BP1 foci (red) indicative of damaged DNA ends. Note the abundance of 53BP1 foci at 24 hours postirradiation in the control and PTEN K254R-reconstituted cells. (Inset) DAPI staining of nuclei.