GSM5550797: U2OS cells, control_crosslink_rep1; Homo sapiens; OTHER
Mnase activity was induced by addition of 3mM CaCl2 for 30 min on ice. Chromatin fragments were released by incubating the samples for 20 minutes at 37°C and centrifugation at 16.000×g for 10 minutes at 4°C. Supernatants were incubated at 70°C in the presence of 0.1% SDS and 5 µg proteinase K. DNA was cleaned-up using phenol/chloroform extraction Libraries were prepared according to the Accel-NGS 1S Plus DNA Library Kit (Swift Bioscience) using the manufactures' protocol suggested for the retention of small fragments ( 40 bp). Libraries were dual indexed and amplified by 14 cycles of PCR with Illumina primers, quantified and analyzed on a Tapestation device (Agilent), pooled in equimolar ratios and purified away from primer and adaptor dimers on a 2% agarose gel.