mRNA processing (e.g., heterogeneous nuclear ribonucleoprotein H1 [Hnrph1], PRP18 pre-mRNA processing factor 18 homolog [Prpf18], and RNA-binding motif protein 16 [Rbm16]) were upregulated. Whereas a number of transcription regulators such as forkhead box A1 (Foxa1), mortality factor 4 like 1 (Morf4l1), and melanocyte-specific gene-related gene 1 (Mrg1) were upregulated, melanoma antigen family D member 1 (Maged1) was suppressed by nicotine. Despite the relative diversity of genes differentially regulated by nicotine in each brain region, it is clear that one or more genes related to the mitochondrial electron transport system were significantly regulated in all these regions.
