Figure 1.

Knockdown and knockout of APTX in U2OS cells. (A) Western blot analysis to determine APTX knockdown (KD) efficiency in U2OS cells using a lentiviral-delivered shRNA system. (B) Repair analysis of 5′-AMP DNA in extracts from APTX KD cells and control cells. (C) Western blot analysis showing complete absence of APTX in CRISPR-mediated APTX knockout (KO) U2OS cells (lane 2) and in cells prepared from AOA1 patients. (D) APTX deficient cells are devoid of 5′-AMP removal activity confirming the specificity of our DNA substrate for APTX activity.