title: GSM5510270: Adult Brain, OmniATAC R16A06 Mef2 RNAi; Drosophila melanogaster; ATAC-seq
library_construction_protocol: 100 GFP-expressing and 15 GFP negative fly brains were dissected in PBS on ice. The brains were then centrifuged at 800 xg for 5 min, after which the supernatant was replaced by 50 μL of dispase (3 mg/mL, Sigma-Aldrich_D4818-2mg), 75 μl collagenase I (100 mg/mL, Invitrogen_17100-017), and 125 μL trypsin-EDTA (0.05%, Invitrogen_25300054). Brains were dissociated at 25°C in a Thermoshaker (Grant Bio PCMT) for 15 min at 25°C at 1,000 rpm and the solution was mixed by pipette every 5 min. After, cell suspensions were passed through a 10 μM pluriStrainer (ImTec Diagnostics_435001050) and viability was assessed by the LUNA-FL Dual Fluorescence Cell Counter. Next, 4 aliquots were made containing GFP-brains cells with/without PI (10%) and GFP-positive brains with/without PI (10%). The GFP-negative brains were used to set the gates on the machine for cell size and viability (PI), the GFP-positive brains for the GFP fluorescence, after which the GFP positive cells with PI were sorted. Between 2.6 and 11k GFP positive cells were sorted and 50k cells per negative control. After sorting, regular omni-ATAC-seq was performed as described by Corces et al. (Corces et al., 2017). omniATAC-seq