What is 5mC in DNA?

Unless you’ve been living under a rock, or maybe under a CpG island, then you’ve heard of 5-methylcytosine (5mC). 5mC is the normal cytosine nucleotide in DNA that has been modified by the addition of a methyl group to its 5 th carbon. The role of this mark is so distinct that many consider 5mC to be the “5 th base” of DNA.

Where is 5mC found?

Almost all 5mC is found in CpG dinucleotides, where it has a crucial role in a number of physiological processes such as genomic imprinting, X-chromosome inactivation and transposon repression. Mammalian DNA methyltransferases, which convert C to 5mC, were first identified in 1982.

What is the difference between 5mC and 5hmC?

In most other tissues, the levels of 5hmC range from about 005% to 0.2% of all cytosines, which is about 20–80 times lower than the levels of 5mC. Predominantly, 5hmC occurs at CpG dinucleotides. Like 5mC, which is a product of DNA methyltransferase activity, 5hmC is produced enzymatically.

What is 5-methylcytosine (5mC)?

5-Methylcytosine (5mC) is an enzymatically produced modified cytosine base that has been known to exist in mammalian DNA for about 70 years. These decades of research have provided important clues as to its presumed functional role but there is no complete understanding yet.