Radioimmunoassay of 5-methyl-2'-deoxycytidine. A method for the quantitation of DNA methylation

5-Methyl-2'-deoxycytidine (5MedCyd) is a minor constituent of mammalian cell DNA. We report the production and characterization of highly specific rabbit anti-5MedCyd antiserum. The antiserum was suitable for the radioimmunological measurement of 5MedCyd. This simple radioimmunoassay was capable of quantitating calf thymus DNA methylation at nanomolar levels of total DNA.