What is DNA Methylation?

"Everyone is a writer" program aims to promote the sharing of knowledge and learning together. We encourage scientists, researchers, and students to answer the questions with their expertise and help  others learn from the answers. There are some answers about the DNA methylation from this campaign.

Q: What is DNA methylation?

A: Lihua Zhang: When I was doing my Ph.d, I took a course "Molecular Biology of The Cell". DNA methylation is stated as one of the epigenetic mechanisms that cells use to regulate gene expression. Typically, it is caused by adding a methyl (CH3) group to DNA and commonly observed in eukaryotic organisms like plants and animals. Based on the previous studies, DNA methylation is highly associated with several human diseases. Learn More

(DNA methylation pathways, refer to Moore et. al Neuropsychopharmacology. 2013 Jan; 38(1): 23–38. doi: 10.1038/npp.2012.112)

Aspen Lin: DNA methylation refers to a biological process by which methyl groups are added to the DNA molecule (Evans, Helen H., 1970). Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription. Learn More

Anh Nguyen: DNA methylation is the process in which a methyl group is attached to a DNA molecule. This is done to repress that part of the DNA as a form of epigenetics. Methlylation can only occur on Adenine and Cytosine bases. Even though DNA methylation is epigenetic it, it can be passed down through replication. There are several factors that makes this possible in Mammals. First, methylation almost exclusively occurs at CpG dinucleotide (this is a C followed by a G when reading in the 5' -> 3' direction). Learn More

Jiale Yang: DNA methylation is the process of selectively adding methyl groups to cytosine to form 5-cytosine under the action of DNA methyltransferase (Dnmt). It was defined as the fifth base when it was first discovered. In fact, it is an important epigenetic marker and plays an important role in the biological processes of regulating gene expression, maintaining chromatin structure, genetic imprinting, X chromosome inactivation and embryo development. It is like the most magical "hat" of DNA, bringing endless surprises to the world. Learn More

Bo Wang: DNA methylation refers to the covalent bonding of a methyl group at the 5 'carbon position of the cytosine of the CpG dinucleotide in the genome under the action of DNA methylation transferase. It can cause changes in chromatin structure, DNA conformation, DNA stability, and the interaction between DNA and protein. It can control gene expression and change genetic performance without changing the DNA sequence. DNA methylation enzymes are divided into 2 categories, namely maintaining DNA methyltransferase (Dnmtl or maintaining methylase) and de novo methylase. Learn More

Manini Penikalapati: DNA methylation occurs when a methyl group (CH3) is added to DNA, most often the 5-carbon of the cytosine ring. These methyl groups inhibit transcription because the shape of the nucleotide is changed, which modifies the function of the genes and affects expression. DNA methylation is epigenetic, meaning that the addition of the methyl group does not affect the sequence of the DNA. It only changes the expression of the gene (phenotype) and is inherited by offspring. In our cells, methylation almost only occurs in a CpG site (cytosine nucleotide next to a guanine nucleotide), and when a methylated CpG site is in a promoter region, the gene is turned off (repressed). Three enzymes called DNA methyltransferases (DNMTs) control the addition and maintenance of methylation levels in cells. Learn More

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