Detecting differences in 5-methylcytosine using restriction enzyme isoschizomers: an endogenous control for complete digestion

Growing research effort inrecent years hasfocused ontherole of 5-methylcytosine (5-MeC) ingeneexpression. 5-MeChasbeen implicated insuch phenomena asgenomic imprinting, maintenance ofheterochromatin, andthedirect control ofgeneexpression through proteins which bindmethylated DNA(1). Asinterest in 5-MeC hasintensified, several newtechniques have beendeveloped tofind andstudy genes under theinfluence of5-MeC(2-4). Despite these newtechniques, Southern blot analysis ofgenomic DNAcut withmethylation-sensitive