Lysates were clarified from sonicated nuclei and protein-DNA complexes were isolated with the respective antibody. We sheared chromatin using Bioruptor until reaching a fragment size of 200-500bp. 10-15μg of chromatin was then used for each replicate H3K27ac ChIP and 30μg for CTCF ChIP. Antibodies: H3K27ac (Diagenode, C15410174) and CTCF (Active motif: 613111) was then performed as in Ibrahim et al. 2013. Libraries were prepared using the Nextera adaptors and sequenced