Fig 8.

Effects of FANCJ and MRE11 depletion on chromosomal instability and DNA repair. (A) The specified control siRNA-, FANCJ siRNA-, and/or MRE11 siRNA-transfected cells were either left untreated or exposed to IR (3 Gy). At the indicated time after IR exposure, cells were fixed and stained with the DNA-PKcs pS2056 antibody. Cells with the noted numbers of pDNA-PKcs foci were counted and expressed as percentages. The graph shows the averages for three independent experiments. More than 100 cells were counted for each sample in each experiment with a P value of <0.001. (B) Metaphase spreads of HeLa cells treated with siRNAs against FANCJ and MRE11 or with control siRNA were treated with IR (2 Gy) in the presence or absence of 10 μM NU-7441 (DNA-PKcs inhibitor) and then analyzed for radial chromosomes. Radial chromosomes are circled. (C) Quantitation of three independent experiments performed as described in panel B. (D and E) I-SceI-induced HR in U2OS cells (D) or NHEJ in MCF7 cells (E) depleted of FANCJ, MRE11, or FANCJ plus MRE11 by siRNA. Percentages of I-SceI-induced GFP⁺ cells were measured. Graphs show the mean values for at least three independent experiments. Error bars indicate SD values.