Cells were fixed in 1% formaldehyde for 8 minutes at room temperature, sonicated on a Bioruptor Pico, incubated for an hour with pre-blocked protein A seppharose beads before being incubated with 1ug of antibody overnight at 4 degrees. The lysate was allowed to incubate with protein A beads before being washed and subejcted to proteinase K digestion Libraries were constructed using NEBnext Ultra DNA library prep kit according to manufactures instructions