title: Formation of O2-methylthymine in poly(dA-dT) on methylation with N-methyl-N-nitrosourea and dimethyl sulphate. Evidence that O2-methylthymine does not miscode during DNA synthesis.
abstract: The alternating co-polymer has been methylated with either N methyl-N-nitrosourea (MNU) or dimethyl sulphate (DMS) and the levels of the various methylated thymidines (O2-methylthymidine, 3-methylthymidine and O4-methylthymidine) measured. MNU produced all three compounds whereas DMS only produced 3-methylthymidine and O2-methylthymidine at detectable levels. These results have been combined with our earlier results concerning the misincorporation of dGMP with E. coli DNA polymerase using MNU-methylated poly(dA-dT). These results indicate that O2-methylthymidine does not miscode during DNA synthesis.
mesh_terms: D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005815:Genetic Code; D008745:Methylation; D008770:Methylnitrosourea; D009607:Nitrosourea Compounds; D011067:Poly dA-dT; D011089:Polydeoxyribonucleotides; D013329:Structure-Activity Relationship; D013941:Thymine / Q000031:analogs & derivatives*
chemical_list: D009607:Nitrosourea Compounds; D011089:Polydeoxyribonucleotides; D011067:Poly dA-dT; D008770:Methylnitrosourea; D004259:DNA-Directed DNA Polymerase; D013941:Thymine