library_construction_protocol: For ATAC-seq, nuclei from 100,000 input BMMs were isolated and ATAC-seq was performed as described (Buenrostro, 2015) except nuclei were spun at 1000 xg. For ATAC-seq, libraries were generated as described (Buenrostro 2015), with additional purification with Ampure XP beads to remove contaminating adaptor dimers.