title: Methylated DNA labels for marking objects.
abstract: We recently described a method for digitally labelling objects with DNA. Here we show that, using DNA methyltransferases to create polymorphic DNA templates, it is possible to significantly increase the number of labels that can be generated by this method. Nine double-stranded DNA templates of different length were methylated with either M.HaeIII or M.AluI methyltransferase, or both. Different mixtures of methylated and unmethylated versions of this template set were used to 'invisibly' label paper. The mixtures were eluted from the paper and the methylated status of the templates in each mixture successfully determined, and the labels read, by digestion with the complementary restriction endonuclease, followed by a polymerase chain reaction and agarose gel electrophoresis. One methylated DNA label was read after it had been left on paper for two months.
authors.affiliation: Department of Chemistry, University of Bath, Bath BA2 7AY UK.
authors.forename: Lindsey J
authors.initials: LJ
authors.lastname: Cook
authors.forename: Jonathan P L
authors.initials: JP
authors.lastname: Cox
mesh_terms: D019843:Archaeal Proteins; D001483:Base Sequence; D004247:DNA / Q000032:analysis* / Q000138:chemical synthesis / Q000737:chemistry*; D019175:DNA Methylation; D008780:Methyltransferases / Q000737:chemistry*; D008969:Molecular Sequence Data; D010209:Paper; D016133:Polymerase Chain Reaction / Q000379:methods; D011356:Product Labeling / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016415:Sequence Alignment / Q000379:methods; D013698:Templates, Genetic
chemical_list: D019843:Archaeal Proteins; D004247:DNA; D008780:Methyltransferases; C023894:methylcobalamin-coenzyme M methyltransferase