CUT&RUN Profiling of Transcription Factors and Histone Modifications

CUT&RUN was performed as previously described [10 (link)]. Briefly, cells were washed with Wash Buffer (20 mM HEPES pH 7.5, 150 mM NaCl, 0.5 mM spermidine and one Roche Complete protein inhibitor tablet per 50 mL), bound to Concanavalin A-coated magnetic beads and incubated with primary antibody diluted in wash buffer containing 0.05% digitonin (Dig Wash) overnight at 4 °C. Cells were then washed and incubated with protein A-MNase (pA-MN) for 1 h at 4 °C. Slurry was washed again and placed on an ice-cold block and incubated with Dig Wash containing 2 mM CaCl₂ to activate pA-MN digestion. After digestion for 30 min, one volume of 2× stop buffer (340 mM NaCl, 20 mM EDTA, 4 mM EGTA, 0.05% Digitonin, 0.05 mg/mL glycogen, 5 µg/mL RNase A, 2 pg/mL heterologous spike-in DNA) was added to stop the reaction, and fragments were released by 30-min incubation at 37 °C. Samples were centrifuged 5 min at 16,000×g, and supernatant was recovered and DNA extracted via phenol–chloroform extraction and ethanol precipitation. Resulting DNA was used as input for library preparation as previously described [10 (link)]. Antibodies used for CUT&RUN in this study were as follows: rabbit anti-Sox2 (Abcam ab92494); rabbit anti-FoxA2 (Millipore 07-633); Guinea-Pig anti-rabbit IgG (antibodies online ABIN101961); rabbit anti-H3K4me2 (Millipore 07-030); rabbit anti-H3K4me3 (Active Motif 39159); rabbit anti-H3K27me3 (Cell Signaling Technologies CST9733); and rabbit anti-CTCF (Millipore 07-729).