Immuno slot blots were performed on whole cell lysates with 6,4 and CPD antibodies via standard methods11 (link). Genomic was isolated using the DNEasy Qiagen Kit per manufacturer’s instructions. DNA concentration was determined by Nanovue nanodrop (GE Healthcare) reading. Equal loading of DNA was confirmed by 4',6-Diamidino-2-Phenylindole, Dihydrochloride (DAPI, 1mg/ml; Thermo Fisher) staining. DNA was denatured at 95°C for 10 minutes, and 0.1 µg was loaded per well on a slot blot apparatus (BioRad) on a nitrocellulose membrane (BioRad). Wells were washed with TE and suction was applied until dry. Membranes were baked (80°C, 1h), blocked in 5% milk (20°C, 1h, TBS buffer, 0.5% Tween), incubated with anti-CPD (Cosmo Biosciences, 1:1,000 dilution, 4°C, overnight), washed, incubated in secondary antibody (HRP-anti-mouse, Abcam, 1:10,000, 20°C, 1h) prior to visualization by ECL using the STORM system.