Fig. 4

Elp1 deficiency impairs homology-directed DNA repair. A Schematics to the HR and NHEJ reporters. B, C Determination of relative HR and NHEJ efficiency using the DR-GFP (B) or EJ5-GFP (C) reporter assay, respectively. U2OS cells were infected with Ctrl or ELP1 shRNAs for 48 h prior to I-SceI transfection. One day after I-SceI expression, GFP-positive cells were analyzed using flow cytometry. Relative HR or NHEJ frequencies were normalized to the percentage of GFP-positive cells in the Ctrl group. The frequency in the Ctrl group with I-SecI expression was set as 100%. Data are presented as mean ± SEM. D, E Expression levels of I-SceI, ELP1 and β-actin were examined in DR-GFP (D) and EJ5-GFP (E) reporter cell lines by immunoblotting. Bars present mean ± SEM. ***p < 0.001 compared to Ctrl cells using Student’s t-test. NS, not-significant