Western blot was performed using Anti-53BP1 Polyclonal Antibody (Product # PA1-46147) and a ~270kDa band corresponding to TP53-binding protein 1 was observed across cell lines tested . Nuclear enriched extracts (30 µg lysate) of HeLa (Lane 1), A549 (Lane 2), MCF7 (Lane 3), U-2 OS (Lane 4), K-562 (Lane 5), U-87 MG (Lane 6) were electrophoresed using NuPAGE™ 3-8% Tris-Acetate Protein Gel (Product # EA0378BOX). Resolved proteins were then transferred onto a Nitrocellulose membrane (Product # LC2001) by iBlot® 2 Dry Blotting System (Product # IB21001). The blot was probed with the primary antibody (1:5000) and detected by chemiluminescence with Goat anti-Rabbit IgG (Heavy Chain) Superclonal™ Recombinant Secondary Antibody, HRP (Product # A27036, 1:4000) using the iBright FL 1000 (Product # A32752). Chemiluminescent detection was performed using Novex® ECL Chemiluminescent Substrate Reagent Kit (Product # WP20005).A streak like pattern was observed in the positive cell lines as expected of 53BP1 target.