Figure 4. MiR-138 affects genomic stability and homologous recombination repair.
(A–B) U2OS cells were transfected with miRNA mimics or H2AX siRNA, irradiated with 2 Gy IR, allowed to recover for 15 hours and then arrested at metaphase. Cells were harvested for metaphase spreading and analysis of chromosome abnormalities. (A) A representative metaphase spread image of U2OS cells overexpressing miR-138. Arrows point out the chromosome abnormalities as indicated. (B) Statistical analysis of chromosome abnormalities (mean ± SD, n=3). Other abnormalities included radial-, dicentric and rejoining chromosomes. (C–F) U2OS DR-GFP cells were sequentially transfected with miRNA mimics or siRNAs and the pBASceI plasmid. Cells were incubated for 48 h, fixed and stained for HA-I-SceI expression and analyzed by FACS of GFP-positive cells in the HA-positive population (C, D) (mean ± SD, n=4), for western blot analysis of BRCA2 and H2AX levels (E), and for cell cycle analysis (F). * P < 0.05, *** P < 0.001