GSM5739623: S22, TP1, RF1, 5; Mus musculus; ATAC-seq
with slight modifications. In brief, the ventral hippocampus was dissected from one side of the brain at -20C°, cut into small pieces and stored in Eppendorf DNA LoBind 2mL tubes at -80°C until nuclei preparation. Nuclei preparation and sorting was performed in 5 batches per each time point, with each batch having exactly one samples from each facility in random order. Total nuclei were then extracted using sucrose gradient centrifugation. Neuronal (NeuN+) nuclei were isolated from non-neuronal nuclei (NeuN-) with fluorescence-activated nuclei sorting  using an anti-NeuN antibody conjugated to AlexaFluor-488 on a FACSAria instrument. For a detailed protocol for nuclei isolation and purification of neuronal nuclei, see the methods section. ATAC-seq libraries were prepared according to Buenrostro et al. 2013 (PMID:24097267) with some modifications. Illumina Tagment DNA TDE1 Enzyme and Buffer Kits (2003419) and IDT for Illumina Nextera DNA UD Indexes (20026930) were used to prepare the libraries.