Figure 3. Observation of γ-H2AX in anti-microRNA 21 (miR-21)-treated U373 cells.
A positive γ-H2AX signal was observed at 1 hour after γ-irradiation in both groups (A; top and bottom of middle panels), whereas its signal persisted up to 24 hours in anti-miR-21-transfected cells (A; bottom of right panel) unlike the negative control transfected cells (A; top of right panel). A quantitative comparison of DNA foci revealed that miR-21 silencing significantly inhibited the repair of DNA damage in U373 cells (p<0.001) (B). DNA foci were counted in up to 300 cells. γ-H2AX and nucleus were labeled with Alexa 488 (FITC; green) and DAPI (blue).