FIGURE 5.

The conserved LKEX₄E motif of CtIP is important for MMEJ-mediated DSB repair. A, schematic of the MMEJ repair assay substrate. B, U2OS EGFP-MMEJ cells stably expressing HA-CtIP 1–897 or indicated mutants, with endogenous CtIP silenced by shRNA and siRNA, were transfected with I-SceI-IRES-dsRedNLS, and 72 h after transfection, the cells were trypsinized, and FACS analysis was performed. The data shown represent the means of three independent experiments; error bars indicate the S.D. Western blot shows expression of HA-CtIP 1–897 and mutants, with Ku70 used as a loading control.