FORMALDEHYDE EFFECT ON DNA METHYLATION AND DEMETHYLATION

摘要

Genomic DNA methylation is one of the most important epigenetic mechanisms. Existing data of indoor air formaldehyde effect on DNA methylation patterns is limited. S-adenosylmethionine, the sole methyl donor in this reaction, is generally connected to the tetrahydrofolate and the methionine-homocysteine cycle and one carbon metabolism. In mammalian systems, as a normal intermediary metabolite, endogenous formaldehyde remains in equilibrium in blood and tissues. There are two ways that endogenous FA can be involved in one carbon pool. One is the production of 5, 10-methlene-THF formed by FA and THF. The second way is through the formation of 10-formyl-THF. Experiments indicate that the oxidation of 10-formyl-THF to 10-formyl-dihydrofolate takes place and 10-formyl- dihydrofolate is subsequently converted to dihydrofolate. Therefore, in light of those circles, we hypothesize that endogenous FA can act as one carbon group to participate in the process of DNA methylation or may cause demethylation through free radical injures.