Author(s): Hepburn PA, Margison GP, Tisdale MJ, Hepburn PA, Margison GP, Tisdale MJ
Abstract Share this page
Abstract The effect of O6-alkylation of guanine residues on the enzymic methylation of cytosine has been studied using synthetic oligonucleotides in which all guanines in cytosine-guanine sequences at potentially methylatable sites are replaced by O6-methylguanine. In contrast with the unmodified forms, which showed high acceptance activity for methyl-3H-labeled groups from S-adenosyl-L-[methyl-3H]methionine in the presence of DNA methylase, the modified oligonucleotides were not substrates for the enzyme either in the single-stranded or annealed forms. In view of the importance of cytosine methylation in the down-regulation of certain genes, the potential to affect gene expression by this mechanism may be a contributory factor in the toxic and carcinogenic effects of chemical methylating agents.
This article was published in J Biol Chem
and referenced in Rice Research: Open Access