Cocaine- and nicotine-induced nucleosome repositioning comparisons.

(A) Changes in nucleosome repositioning that were unique to nicotine or cocaine, and common to both the drugs. (B-E) Nucleosome repositioning in response to nicotine or cocaine exposure is shown. (B) Nucleosome repositioning upstream of TSS, at the TSS and at the beginning of the coding sequence in the CDNK1C gene around the TSS was induced by nicotine and not by cocaine (nicotine-specific). Nicotine exposure positioned nucleosomes upstream of the TSS, depleted the nucleosomes at the TSS, and positioned nucleosomes at the start of the coding sequence. On the other hand, cocaine exposure for 20 min, did not produce changes in nucleosome position compared to the drug naïve state. (C) Nicotine and cocaine both induced nucleosome repositioning upstream of TSS, at the TSS and at the beginning of the coding sequence in the ANGPT2 gene. However, 60 min cocaine-specific changes were detected at the +1 nucleosome (asterisk), just downstream of the ANGPT2 TSS. The 60 min nicotine-induced nucleosome repositioning at ANGPT2 is similar to the 20 min time point and therefore is not shown. (D) Changes common to nicotine (10 min) and cocaine (20 min) just upstream and downstream of the TSS of FNB2 gene. (E) Neither nicotine (10 min) nor cocaine (20 min) produced nucleosome repositioning across the promoter and 5’ region of BMP3. Nucleosome positions relative to the TSS and coding sequence of each gene in the drug naïve (black) and drug exposed (red) states are further illustrated pictorially at the bottom of the figure. Each sphere (black or red) represents a nucleosome.