Chromatin immunoprecipitations were performed as described previously, with adaptations (Schmidt et al., 2009). In short, cells were crosslinked in solution A (pH 7.4, 50mM Hepes, 100mM NaCl, 1mM EDTA, 0.5M EGTA) containing 2mM DSG for 35 minutes, then formaldehyde was added to a final concentration of 1% and incubated for another 10 minutes. After addition of Glycine to a final concentration of 125mM to quench the crosslinking reaction and washing with PBS, cells were collected. The Bioruptor Pico (Diagenode) was used for sonication. For ChIP, antibodies were used to detect the HA-tag (25mg, 05-904, Millipore) and GATA3 (10 mg, sc-268, Santa Cruz) with 100 ml Protein A magnetic beads (Thermo Scientific). Immunoprecipitated DNA was processed for library preparation (Part# 0801-0303, KAPA biosystems kit).