![]() Eukaryotic gene expression begins with control of access to the DNA. Unlike prokaryotic cells, eukaryotic cells can regulate gene expression at many different levels. These different patterns of gene expression cause your various cell types to have different sets of proteins, making each cell type uniquely specialized to do its job.Įukaryotic gene expression is more complex than prokaryotic gene expression because the processes of transcription and translation are physically separated. Thanks to gene regulation, each cell type in your body has a different set of active genes – despite the fact that almost all the cells of your body contain the exact same DNA. Gene regulation is how a cell controls which genes, out of the many genes in its genome, are “turned on” (expressed). Almost all of your cells contain the same set of DNA instructions: so why do they look so different, and do such different jobs? The answer: different gene regulation! Your amazing body contains hundreds of different cell types, from immune cells to skin cells to neurons. What you’ll learn to do: Discuss different components and types of epigenetic gene regulation RNA splicing, the first stage of post-transcriptional control.Post-Transcriptional Control of Gene Expression.Turning Genes Off: Transcriptional Repressors.The Promoter and the Transcription Machinery.Eukaryotic Transcription Gene Regulation.What you’ll learn to do: Discuss different components and types of epigenetic gene regulation.In regions of DNA with activate transcription, Tet removes DNA methylation, and histone tails in this region often contain H3K4me 3 that inhibits Dnmt binding to unmethylated CpG sites and maintains a permissive environment for transcription.\) DNA methylation is recognized by methyl-binding proteins such as MBDs (yellow) that along with Dnmts recruit enzymes that modify the histone tails (orange) including histone deacetylases (HDACs), which remove acetylation (red), and histone methyltransferases (HMTs), which methylate histones (green) and in conjunction with DNA methylation serve to further repress gene expression. For some Dnmts, their catalytic activity is enhanced by association with histone tails and with Dnmt3L. To suppress gene expression, Dnmts target CpG sites and actively methylate DNA. Methylation is regulated by proteins such as Dnmt and Tet (purple) that are involved in the active addition or chemical modification (such as hydroxymethylation in red) of DNA methylation. Transcription is ultimately regulated by the interaction of multiple epigenetic mechanisms that cooperate to activate or silence gene expression. The investigation into DNA methylation continues to show a rich and complex picture about epigenetic gene regulation in the central nervous system and provides possible therapeutic targets for the treatment of neuropsychiatric disorders.Įpigenetic crosstalk. Indeed, when DNA methylation is altered as a result of developmental mutations or environmental risk factors, such as drug exposure and neural injury, mental impairment is a common side effect. The precise regulation of DNA methylation is essential for normal cognitive function. Moreover, neuronal activity can modulate their pattern of DNA methylation in response to physiological and environmental stimuli. ![]() ![]() Intriguingly, postmitotic neurons still express DNA methyltransferases and components involved in DNA demethylation. We will describe the DNA (de)methylation machinery and its association with other epigenetic mechanisms such as histone modifications and noncoding RNAs. In this chapter, we will review the process of DNA methylation and demethylation in the nervous system. As a consequence, differentiated cells develop a stable and unique DNA methylation pattern that regulates tissue-specific gene transcription. ![]() During development, the pattern of DNA methylation in the genome changes as a result of a dynamic process involving both de novo DNA methylation and demethylation. DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s) to DNA. In the mammalian genome, DNA methylation is an epigenetic mechanism involving the transfer of a methyl group onto the C5 position of the cytosine to form 5-methylcytosine.
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