Arima H3K27Ac HiChIP (Arima: A101020) was performed according to the manufacturers provided instructions using unspecified proprietary buffers, solutions, enzymes, and reagents. Briefly, cells were fixed as in promoter capture Hi-C above and the amount of fixed cell suspension equal to 15g of cell DNA was used for the HiC reactions as in promoter capture Hi-C above. The samples were then sonicated 25 cycles (30s on/ 30s off) using a Diagenode Bioruptor Plus bath sonicator. Chromatin immunoprecipitation of the sonicated HiC samples was performed by first incubating the samples with 0.2ug of H3K27 antibody (Active Motif 91194) per 1ug of sample overnight. The next day antibody bound chromatin was collected using protein A beads included in the kit. The beads were washed three times with buffer R1, twice with buffer R3, once with buffer LC and then twice with LTE (buffers specified in Arima kit). Samples were eluted before undergoing decrosslinking. Libraries were prepared using Swift Biosciences Accel-NGS 2S Plus DNA Library Kit (Cat # or 21096) following instructions provided by Arima Genomics. The paired-end libraries were sequenced on the Illumina Novaseq to generate >200M 150bp reads. The provided FitHiChIP pipeline was used for analysis to call 5kb resolution loops in relaxed background mode (https://github.com/ay-lab/FitHiChIP)