[Destiny of 5-methylcystosine of newly synthesized DNA fraction in bone marrow cells].
Methylation kinetics of newly formed DNA in bone marrow cell culture of animals and healthy humans was studied in order to investigate the role of DNA methylation in proliferation and differentiation of hematopoietic cells. Synthesis of a DNA fraction with extremely high cytosine methylation level was observed under the incubation of cells with 14C-orotic acid for 0.5-1 hour. Long-term incubation (3 and more hours) with 14C-orotic acid resulted in a rapid decrease of 5-methylcytosine radioactivity and in an increase of thymine radioactivity. Elimination of 14C-orotate from the medium and inhibition of DNA synthesis with hydroxyurea did not change kinetics of the radioactivity content in 5-methylcytosine and thymine in newly synthesized DNA. No synthesis of hypermethylated DNA fraction was observed under incubation of cells with preformed pyrimidine precursors.
D000818:Animals; D001853:Bone Marrow / Q000187:drug effects / Q000378:metabolism*; D001854:Bone Marrow Cells; D003596:Cytosine / Q000031:analogs & derivatives* / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis*; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology; D007700:Kinetics; D008745:Methylation; D009963:Orotic Acid / Q000494:pharmacology; D051381:Rats
D009963:Orotic Acid; D003596:Cytosine; D004247:DNA; D006918:Hydroxyurea
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