title: GSM8027490: MUSIC_H1_E14_mix_species; Homo sapiens; Mus musculus; OTHER
library_construction_protocol: Cells were crosslinked with 2 mM disuccinimidyl glutarate (DSG) and 3% formaldehyde (FA). The crosslinking reaction was quenching by adding 3 mL of 2.5 M glycine per 10 mL of 3% formaldehyde. Five million cells were lysed in 1.4 mL of cell lysis buffer A (50 mM HEPES pH 7.4, 1 mM EDTA pH 8.0, 1 mM EGTA pH 8.0, 140 mM NaCl, 0.25% Triton X-100, 0.5% IGEPAL CA-630, 10% glycerol, 1X proteinase inhibitor cocktail (PIC)) followed by a 10-min incubation in lysis buffer B (10 mM Tris-HCl pH 8, 1.5 mM EDTA, 1.5 mM EGTA, 200 mM NaCl, 1X PIC) for 10 min. Isolated nuclei were further permeabilized in 0.25% SDS solution at 62°C for 10 min, and the reaction was quenched with 10% Triton X-100 (wt/vol) at 37°C for 15 min. After the RNA and DNA linker ligations, three rounds of cell barcode ligations, dA-tailling, 10X barcode addition, and library amplification with multiple indexed i7, the molarity of the sequencing library was measured by Qubit 4.0 Fluorometer (Invitrogen, Q33238) using Qubit dsDNA HS assay kit (Invitrogen, Q33231). Fragment size distribution was assessed by Agilent bioanalyzer with High sensitivity DNA ChIP. The library was sequenced by UC San Diego IGM Genomics Center utilizing an Illumina NovaSeq 6000. The sequencer is set to read a 28 bp sequence next to the Universal Adapter as the Read1, a 8 bp index sequence from the I7 region inside the Index Adapter, and a 150 bp sequence next to the Index Adapter as the Read2.