title: GSM2264513: C3_H3R2Me2A; Mus musculus; ChIP-Seq
library_construction_protocol: 3 fully independent biological replicates for saline and for cocaine treatment were obtained for H3R2me2a. For each ChIP-seq replicate, bilateral 14-gauge NAc punches were pooled from 10 mice. Tissue was lightly fixed to cross-link DNA with associated proteins, and the material was further sheared (Bioruptor to obtain mostly 100-300 bps fragments) and immunoprecipitated using sheep anti-rabbit magnetic beads (Invitrogen) conjugated to an antibody that specifically recognizes H3R2me2a (Millipore 04-808) and which we validated extensively. Immunoprecipitated DNA were prepared for ChIP-seq using an Illumina kit according to the manufacturer’s instructions. Each sample underwent end repair followed by addition of an A base to the 3′ end. Proprietary adapters were then ligated to the ends, followed by size selection on a 2% agarose gel. The range of excision was 200–300 bp. After DNA clean up, samples were amplified with 21 cycles of PCR. Amplification and size selection were confirmed with a BioAnalyzer. The resulting libraries were sequenced on an Illumina HiSeq 2500 with 100 bp read length.