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DNA methylation is an important regulator of gene expression and is usually associated with gene repression. DNA Methylation is a mechanism which can suppress gene expression. It can be inherited through cell divisions in development, and is involved with cell memory. Changes in methylation occur due to mutated or deregulated chromatin regulators.
DNA methylation appears absolutely required in differentiated cells, as knockout of any of the three competent DNA methyltransferase results in embryonic or post-partum lethality. By contrast, DNA methylation is dispensable in undifferentiated cell types, such as the inner cell mass of the blastocyst, primordial germ cells or embryonic stem cells.
DNA methylation can be stable during cell division, allowing for methylation states to be passed to other orthologous genes in a genome. DNA methylation can be reversed via enzymes known as DNA de-methylases, while histone modifications can be reversed by removing histone acetyl groups with deacetylases. The process of DNA methylation reversal ...
The first epigenetic modification to be characterized in depth was DNA methylation. As its name implies, DNA methylation is the process by which a methyl group is added to DNA. The enzymes responsible for catalyzing this reaction are the DNA methyltransferases (DNMTs). While DNA methylation is stable and heritable, it can be reversed by an ...
Epigenetic mechanisms. In biology, epigenetics is the study of heritable traits, or a stable change of cell function, that happen without changes to the DNA sequence. [1] The Greek prefix epi-(ἐπι-"over, outside of, around") in epigenetics implies features that are "on top of" or "in addition to" the traditional (DNA sequence based) genetic mechanism of inheritance. [2]
However, some epigenetic marks, particularly maternal DNA methylation, can escape this reprogramming; leading to parental imprinting. [citation needed] In the primordial germ cells (PGC) there is a more extensive erasure of epigenetic information. However, some rare sites can also evade erasure of DNA methylation. [29]
The human epigenome, including DNA methylation and histone modification, is maintained through cell division (both mitosis and meiosis). [2] The epigenome is essential for normal development and cellular differentiation , enabling cells with the same genetic code to perform different functions.
DNA (cytosine-5)-methyltransferase 3A (DNMT3A) is an enzyme that catalyzes the transfer of methyl groups to specific CpG structures in DNA, a process called DNA methylation. The enzyme is encoded in humans by the DNMT3A gene. [5] [6] This enzyme is responsible for de novo DNA methylation. Such function is to be distinguished from maintenance ...