each region in a separate set of experiments (Table S1; see below). Tubes containing digested tissue were transferred onto ice and the “Dissociation Buffer + Enzyme” replaced with 10 ml of “Dissociation Buffer + Stop Solution” containing “Dissociation Buffer” and 1 mg/ml Trypsin Inhibitor (Sigma-Aldrich, T6522), 2 mg/ml BSA (Sigma-Aldrich, A2153) and 1 mg/ml Ovomucoid Protease Inhibitor (Worthington, LK003153). Tissue chunks were then carefully titrated with a series of n=4 fire-polished, Pasteur pipets with successively smaller bores. Bubbles were avoided. Falcon tubes containing 10 ml of titurated cells were then centrifuged at 300 g for 10 minutes. The supernatant was removed and discarded, taking care not to disturb the cell pellet. The pellet was then resuspended in 5 ml of “Dissociation Buffer + Stop Solution” and centrifuged again using the same conditions. The supernatant was again removed. The cleaned cell pellet was resuspended in “Dissociation Buffer” containing 0.01% BSA (w/v; “Dissociation Buffer + BSA”). The volume of resuspension depended on the region (Table S1). Suspensions were then passed through a pre-wet 40 μm filter into a new tube on ice. N=2 10 μl samples were then drawn from the tube and mixed 1:1 with 10 μl of 2× dye mix
