causes transcriptional repression (Allis et al., 2007). Histone covalent modifications are dynamically regulated by the actions of deacetylases, serine-threonine phosphatases, lysine demethylases, deiminases and ubiquitin proteases that act to reverse the corresponding modifications. Thus, the epigenetic regulation of gene expression becomes a very complex phenomenon that warrants a greater understanding of how these histone modifications interact with each other. This has been likened to a functional ‘code’ that presumably may lead to specific functional outcomes when specific combinations of modifications are present (Strahl & Allis, 2000). We will first describe histone acetylation and deacetylation mechanisms in the brain and their implications in alcoholism and other brain disorders.
