Preferential binding of DNA methyltransferase and increased de novo methylation of deoxyinosine containing DNA.
Mammalian DNA-cytosine 5-methyltransferases methylate cytosines in deoxyinosine containing DNA polymers more rapidly than in other synthetic or naturally occurring DNAs. The initial methylation rate of poly(dI-dC) X poly(dI-dC) is about 10-times higher than that of poly-(dG-dC) X poly(dG-dC) or of the native Micrococcus luteus DNA. In competitive binding experiments, DNA methyltransferase has about 10-fold higher affinity for the dI-containing alternating DNA polymer than for poly(dG-dC) X poly(dG-dC). The observed high methyl accepting capacity of poly(dI-dC) X poly(dI-dC) may be a useful methodological advance to determine de novo DNA methyltransferase activity in extracts of mammalian cells.
D000818:Animals; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008745:Methylation; D051379:Mice; D009690:Nucleic Acid Conformation; D011089:Polydeoxyribonucleotides / Q000378:metabolism*
D011089:Polydeoxyribonucleotides; C031156:poly d(I-C); C019530:poly(dC-dG); D004248:DNA (Cytosine-5-)-Methyltransferases