5-Hydroxymethyl-deoxycytidine (hmdC) is an oxidized form of 5-methyldC.
Modified 2’-deoxycytosine is available as a 5', internal or 3’ modification to modify oligonucleotide cytosine residues with an hydroxymethyl group. This modification has a great interest in epigenetic studies and gene expression research.
Epigenetic events occur on nucleotide sequences. DNA methylation (5-Me-dC) is one of the most studied events. This modification mediated by the DNA methyltransferase enzymes occurs on the cytosine amino acid of CpG dinucleotide sites with a strong presence in GC-rich promoters.
Oxidations of 5-Me-dC by the TET (ten eleven translocation) oxygenases generate 5-hydroxymethyl-cytosine (5hmC), which can be oxidized into 5-formyl-cytosine (5fC). An additional oxidation step generates the 5-carboxycytosine (5caC).
5-Me-dC has been shown to be involved in the gene expression regulation. The misregulation of the DNA methylation has been identified as a marker for cancers. Studying DNA methylation pattern and detecting aberrant methylation amount could open new paths in cancer research and diagnostic.