In mammalian genomes, 5-mC can be enzymatically oxidized to 5-hmC (5-hydroxymethylcytosine). There is intense scientific curiosity on identifying the epigenetic mechanisms and functions of the 5-hmC. This modification is suggested to be an intermediate between methylation and demethylation of the genome. Occupancy of 5-hmC correlates with inactive or non-productive promoters (1). 5-hmC pattern is different from 5-methylcytosine (5-mC) in many instances (2). Recently, a few analytical methods like chromatography coupled to mass spectroscopy and 5-hmC DNA immunoprecipitation have been developed to quantitate and analyze 5-hmC. However, all the methods fall short of acheiving quantitative site specific resolution.
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