DNA methylation is an epigenetic event in which DNA methyltransferases (DNMTs) catalyze the reaction of a methyl group to the fifth carbon of cytosine in a CpG dinucleotide. This modification helps to control gene expression and is also involved in genomic imprinting, while aberrant DNA methylation is often associated with disease. 5-methylcytosine is a modified base that is found in the DNA of plants and vertebrates.
A second type of DNA methylation exists, 5-hydroxymethylcytosine (5-hydroxy methylcytosine, 5-hmC). This results from the enzymatic conversion of 5-methylcytosine into 5-hydroxymethylcytosine by the TET family of cytosine oxygenases. Iterative activity of TET on 5-hydroxymethylcytosine results in the conversion of 5-hmC into 5-formylcytosine and 5-carboxylcytosine. An increase in levels of 5-formylcytosine and 5-carboxylcytosine are detected in the mouse male pronucleus following fertilization, which is gradually diluted by DNA replication.
DNA methylation is an epigenetic event in which DNA methyltransferases (DNMTs) catalyze the reaction of a methyl group to the fifth carbon of cytosine in a CpG dinucleotide. This modification helps to control gene expression and is also involved in genomic imprinting, while aberrant DNA methylation is often associated with disease. 5-methylcytosine is a modified base that is found in the DNA of plants and vertebrates.
A second type of DNA methylation exists, 5-hydroxymethylcytosine (5-hydroxy methylcytosine, 5-hmC). This results from the enzymatic conversion of 5-methylcytosine into 5-hydroxymethylcytosine by the TET family of cytosine oxygenases. Iterative activity of TET on 5-hydroxymethylcytosine results in the conversion of 5-hmC into 5-formylcytosine and 5-carboxylcytosine. An increase in levels of 5-formylcytosine and 5-carboxylcytosine are detected in the mouse male pronucleus following fertilization, which is gradually diluted by DNA replication.
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