DNA methylation occurs mainly at the 5’-position of cytosine rings (5-methylcytosine) and occurs almost exclusively in CpG islands. Another epigenetic modification in DNA has been recently identified that involves hydroxymethylation of this same base (5-hydroxymethylcytosine), which potentially offers another level of transcriptional control. 5-(Hydroxymethyl)-2’-deoxycytidine is a modified pyrimidine that is capable of producing interstrand cross-links in double-stranded DNA and has been used to quantify DNA hydroxymethylation levels in biological samples.
5-(Hydroxymethyl)-2’-deoxycytidine is a modified pyrimidine that is capable of producing interstrand cross-links in double-stranded DNA and has been used to quantify DNA hydroxymethylation levels in biological samples.[Cayman Chemical]
5-(hydroxymethyl)-2'-deoxycytidine (5-hmdC), the oxidative product from 5- (methyl)-2'-deoxycytidine (5-mdC) by TET protein, plays critical roles in a variety of physiological processes such as DNA demethylation, cellular differentiation, and epigenetic regulation, etc. In addition, 5-hmdC has also been demonstrated as a potential biomarker reflecting the diagnosis and prognosis of multiple diseases. Some studies have reported that the level of 5-hmdC significantly decreases in diversified cancers, which suggests its important role in tumor formation and development. In 2009, breakthrough studies found that the 5-hmdC is not the unique oxidative product of 5-mdC. 5-(hydroxymethyl)-2'-deoxycytidine is a crucial intermediate product of the DNA demethylation pathway, which can act as potential biomarkers reflecting the diagnosis and prognosis in multiple tumors. 5-hmdC in human urine is in the form of single deoxynucleosides produced by DNA degradation or metabolism, which can avoid digestion. 5-hmdC has been identified in human urine[1].
[1] Mengzhe Guo. “Enrichment and Quantitative Determination of 5-(Hydroxymethyl)-2′-deoxycytidine, 5-(Formyl)-2′-deoxycytidine, and 5-(Carboxyl)-2′-deoxycytidine in Human Urine of Breast Cancer Patients by Magnetic Hyper-Cross-Linked Microporous Polymers Based on Polyionic Liquid.” Analytical Chemistry 90 6 (2018): 3906–3913.
