Figure 2.

Inhibition of homologous recombination but not nonhomologous end joining by OA-NO₂. A and B, U2OS cells containing the HR reporter construct DR-GFP were transfected with an I-SceI plasmid and treated with vehicle (gray), 5 μm OA (green), or 5 μm OA-NO₂ (red). Negative control cells did not have I-SceI present. Values indicate average, and error bars represent S.E.; n ≥ 3. A, the number of GFP-positive cells was detected by flow cytometry at 48 h. B, emergence of GFP-positive cells over 68 h was quantified using live-cell fluorescence microscopy. GFP-positive cell counts were normalized to cell confluence and compared. C and D, U2OS cells containing the NHEJ reporter construct EJ5-GFP were transfected with an I-SceI plasmid and treated with vehicle (gray), 5 μm OA (green), or 5 μm OA-NO₂ (red). Negative control cells did not have I-SceI present. Values indicate average, and error bars represent S.E.; n = 3. C, the number of GFP-positive cells were detected by flow cytometry at 48 h. D, emergence of GFP-positive cells over 68 h was quantified using live-cell fluorescence microscopy. GFP-positive cell counts were normalized to cell confluence and compared.