CRISPR-Cas9 mediated genome editing of PARP1 (as confirmed by next generation sequencing) was achieved by using LentiArray™ Lentiviral sgRNA (Product # A32042, Assay ID CRISPR978664_LV) and LentiArray Cas9 Lentivirus (Product # A32064). Western blot analysis of PARP1 was performed by loading 30 µg of HeLa Wild Type (Lane 1), Treated HeLa Wild Type (Lane 2), HeLa Cas9 (Lane 3), Treated HeLa Cas9 (Lane 4), HeLa Cas9 cells transduced with PARP1 Lentiviral sgRNA (Lane 5) and Treated HeLa Cas9 cells transduced with PARP1 Lentiviral sgRNA (Lane 6) whole cell extracts. The samples were electrophoresed using NuPAGE™ Novex™ 4-12% Bis-Tris Protein Gel (Product # NP0322BOX). Resolved proteins were then transferred onto a nitrocellulose membrane (Product # IB23001) by iBlot® 2 Dry Blotting System (Product # IB21001). The blot was probed with Anti-PARP1 Polyclonal Antibody (Product # PA3-951) using 1:500 dilution and Goat anti-Rabbit IgG (H+L) Superclonal™ Recombinant Secondary Antibody, HRP (Product # A27036 1:4,000 dilution). Chemiluminescent detection was performed using Novex® ECL Chemiluminescent Substrate Reagent Kit (Product # WP20005). Even though NGS analysis determine the clone as partial KO, there was complete loss of signal in sgRNA transduced cells using the LentiArray™ CRISPR product line confirming that the antibody is specific to PARP1. An uncharacterized band was observed at 55 kDa in all the samples. Treatment used is 1 µ