Epigenetic regulation and chromatin remodeling in learning and memory

Understanding the underlying mechanisms of memory formation and maintenance has been a major goal in the field of neuroscience. Memory formation and maintenance are tightly controlled complex processes. Among the various processes occurring at different levels, gene expression regulation is especially crucial for proper memory processing, as some genes need to be activated while some genes must be suppressed. Epigenetic regulation of the genome involves processes such as DNA methylation and histone post-translational modifications. These processes edit genomic properties or the interactions between the genome and histone cores. They then induce structural changes in the chromatin and lead to transcriptional changes of different genes. Recent studies have focused on the concept of chromatin remodeling, which consists of 3D structural changes in chromatin in relation to gene regulation, and is an important process in learning and memory. In this review, we will introduce three major epigenetic processes involved in memory regulation: DNA methylation, histone methylation and histone acetylation. We will also discuss general mechanisms of long-term memory storage and relate the epigenetic control of learning and memory to chromatin remodeling. Finally, we will discuss how epigenetic mechanisms can contribute to the pathologies of neurological disorders and cause memory-related symptoms. Epigenetic changes help control learning and memory, and contribute to memory-related brain disorders. In a review article, Somi Kim and Bong-Kiun Kaang from Seoul National University, South Korea, discuss how epigenetic changes (the addition of chemical tags to DNA or to the histone proteins that act as spools around which DNA winds) can influence gene regulation to affect memory formation and storage. The researchers describe three main epigenetic processes - DNA methylation, histone methylation and histone acetylation - all of which can drive or repress the expression of genes involved in memory promotion or suppression. These epigenetic mechanisms also collectively affect the physical structure of the DNA-protein complexes in ways that influence memory formation and consolidation. A better understanding of this epigenetic regulation could lead to new therapies for neurological conditions such as Huntington's disease.