GSM8634311: ChIP_Pol2_mm10_brain_Young3; Mus musculus; ChIP-Seq
Mouse brains were dissected from the euthanized mice under the Northwestern University protocol. Immediately after collection of these organs, they were snap frozen in liquid nitrogen for future use. Briefly, snap-frozen mice brain tissues were washed with PBS twice before mincing them. Next, the samples were washed again with PBS before low-speed centrifugation at 2,000xG for 3 minutes. Then the samples were homogenized in PBS and passed through a cell strainer (100 micron). Crosslinking was done by 1% formaldehyde at a density of for 15 minutes at 4C. Then glycine was used to quench formaldehyde to 0.125M concentration for 5 minutes at room temperature. Next, the cells were washed with PBS twice each time pelleted at 2,000xG, snap frozen in liquid nitrogen and stored at –80 for further processing. For ChIP, lysis buffer 1 was used to lyse the cells at a density of 1x107 cells per ml and incubation for 10 minutes on ice.  DNA was purified using a ChIP DNA Clean and Concentrator kit (Zymo, D5205). Further details can be found in the Methods section. Libraries were made using the KAPA HTP Biosystems Library Prep kit (Roche, KK8234) using Perkin Elmer Unique Dual Index Barcodes for Illumina system. Sequencing was done on an Illumina NextSeq 2000 instrument as paired-end 50b reads.