Maternal cocaine administration in rats increased methylation at a CpG site in the promoter of the protein kinase Cε (PKCε) gene in fetal heart, and decreased PKCε mRNA and protein levels, presumably through a decrease in Ap1 transcription factor binding (Zhang et al, 2007). DNA methylation of the glucocorticoid receptor promoter in rats was shown to be altered in offspring by maternal behavior (Weaver et al, 2004). In humans, the RELN promoter was found to be hypermethylated, with reduced expression in the brains of schizophrenic patients (Abdolmaleky et al, 2005; Grayson et al, 2005). Mutations in the transcriptional repressor MeCP2, which binds methylated CpG dinucleotides, cause neuropsychiatric abnormalities including Rett syndrome (Chahrour and Zoghbi, 2007).
