摘要
Epigenetic mechanisms regulate the chromatin structure and gene expression levels without changing the primary DNA sequence,and include DNA methylation and hydroxymethylation,post-translational modifications of histone tails and nucleosome positioning,as well as mechanisms mediated by long and short non-coding RNA molecules.These mechanisms are required for human development and cell differentiation,and are pivotal in differentiated cells for cellular functions,allowing a tight regulation of gene expression levels in response to environmental stimuli and cellular metabolic demands(Coppedè,2021b).Particularly,the neuronal epigenome is highly sensitive to external stimuli and its function is required for learning and memory processes(Creighton et al.,2020).Several enzymes,collectively referred to as the“epigenetic machinery”,add,remove and read epigenetic marks,allowing chromatin remodeling to promote or repress gene transcription.The activity of these enzymes allows the reversibility of epigenetic marks,which is pivotal in neurons for memory formation and consolidation(Creighton et al.,2020).
