title: GSM7030706: Acinar cells, p53 wild-type, biol.rep3; Mus musculus; ATAC-seq
library_construction_protocol: The pancreata from mice were resected and dissociated. Briefly, dissociation was done through consecutive steps, starting with collagenase (2.5 mg/mL of collagenase D + 0.1 mg/mL DNAse I in HBSS) for 10 min at 37°C, warm Trypsin-EDTA solution (0.05%) for 5 min at 37°C, DNAse I (0.1 mg/mL in PBS) and warm dispase solution (2 U/mL of dispase + 0.1 mg/mL DNAse I in PBS). After dissociation, acinar cells were sorted using a surface marker for acinar cell identity (CD49F), as well as markers to exclude ductal-like cells (CD133), erythroid (TER-119) and immune cells (CD45). 50,000 acinar cells from single cell suspensions were washed in PBS and resuspended in lysis buffer (10mM Tris-HCl, pH 7.5, 10mM NaCl, 3mM MgCl2, an 0.1% IGEPAL CA-630), followed by centrifugation and removal of supernatant. Transposition mix (1x TD from Illumina and 2.5 ul of Tn5 transposase in 50ul total) was added to the cell pellet and transposition proceeded at 37˚C for 30 minutes. At the end of the transposition reaction, DNA was purified with a Qiagen minElute column. To create sequencing libraries, transposed DNA was amplified and indexed with Illumina Nextera sequencing primers as previously described (Buenrostro et. al., Nat Meth 10, 1213-1218 (2013)).