Chromatin immuneprecipitation (ChIP) was performed as previously described (42) using the NAc from rats that underwent the self-administration paradigm. 30ug of purified chromatin per animal was immuneprecipitated with 1.25ug of ELK1 antibody (Epitomics, Burlingame, CA) or nonspecific rabbit IgG (Santa Cruz Biotechnology, Santa Cruz, CA). Chromatin was analyzed by QPCR at genomic regions of BAG1 and USE1. Primer sequences are listed in supplementary table 3. Statistical analyses as described above were performed using JMP software.
