Mammalian DNA methyltransferases prefer poly(dI-dC) as substrate.
The synthetic duplex DNA, poly(dI-dC).poly(dI-dC), is methylated in vitro by human or murine DNA methyltransferases at 20-100 times the rate of other nonmethylated DNAs. Preparation of the hemimethylated derivative, poly(dI-dMeC).poly(dI-dC), of this polymer increases its effectiveness as a substrate by 2-fold, making it 4-10 times more effective as a substrate for mammalian DNA methyltransferases than any other hemimethylated DNA so far reported. However, the apparent slower rate of de novo methylation of poly(dI-dC).poly(dI-dC) as compared to the hemimethylated derivative is due to substrate inhibition, unique to the unmethylated polymer, as the rates of de novo and maintenance methylation are identical at low substrate concentrations.
G
G
Pedrali-Noy
A
A
Weissbach
D000818:Animals; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D004256:DNA Polymerase I / Q000378:metabolism; D006367:HeLa Cells / Q000201:enzymology; D006801:Humans; D007700:Kinetics; D051379:Mice; D011070:Poly I-C / Q000378:metabolism*; D011089:Polydeoxyribonucleotides / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism; D013379:Substrate Specificity; D014316:Tritium
D011089:Polydeoxyribonucleotides; D014316:Tritium; D012436:S-Adenosylmethionine; D004248:DNA (Cytosine-5-)-Methyltransferases; D004256:DNA Polymerase I; D011070:Poly I-C